id int64 39 79M | url stringlengths 31 227 | text stringlengths 6 334k | source stringlengths 1 150 ⌀ | categories listlengths 1 6 | token_count int64 3 71.8k | subcategories listlengths 0 30 |
|---|---|---|---|---|---|---|
64,784,389 | https://en.wikipedia.org/wiki/Pinch%20point%20hazard | A pinch point or pinch point hazard is a common class of mechanical hazard where injury or damage may be done by one or more objects moving towards each other, crushing or shearing whatever comes between them. A nip point is a type of pinch point involving rotating objects, such as gears and pulleys. Injuries can range from minor such as blisters to severe like amputations and fatalities. Examples of pinch point hazards include gaps in closing doors and objects swinging or being lowered near fixed objects.
Common causes of injuries
Poor situational awareness
Proximity to mobile equipment and fixed structures
Loose clothing, hair or jewelry getting caught in rotating parts or equipment
Inadequate safety barriers
Handling errors
Wrong work procedures or tools
Reaching into moving equipment
Safety controls
Pre-work hazard inspections can be performed to identify pinch point hazards. These hazards can be managed with control methods, listed below according to the hazard control hierarchy.
Engineering controls physically prevent objects from entering the pinch point.
Barriers and machine guards
Administrative controls inform worker behavior to avoid pinch points.
Area demarcation
Lockout–tagout
Situational awareness
Use of appropriate training, work procedures, instructions, and operating manuals
Personal protective equipment protects individuals exposed to the hazard by preventing objects from being pinched..
See also
Mechanical hazard- Hazard with a mechanical energy source
References
Technology hazards | Pinch point hazard | [
"Technology"
] | 261 | [
"nan"
] |
64,785,482 | https://en.wikipedia.org/wiki/Blanet | A blanet is a member of a hypothetical class of exoplanets that directly orbit black holes.
Blanets are fundamentally similar to other planets; they have enough mass to be rounded by their own gravity, but are not massive enough to start thermonuclear fusion and become stars. In 2019, a team of astronomers and exoplanetologists showed that there is a safe zone around a supermassive black hole that could harbor thousands of blanets in orbit around it.
Etymology
The team led by Keiichi Wada of Kagoshima University in Japan has given this name to black hole planets. The word is a portmanteau of black hole and planet.
Formation
Blanets are suspected to form in the accretion disk that orbits a sufficiently large black hole.
Possible candidates
The unconfirmed extragalactic planet M51-ULS-1b.
The unconfirmed planet or brown dwarf, IGR J12580+0134 b, being disrupted by a supermassive black hole.
In fiction
In the two episodes "The Impossible Planet" and "The Satan Pit" (both 2006) of the British television series Doctor Who, the plot of the episode takes place on the titular “impossible planet”, a barren blanet called Krop Tor orbiting a black hole called K37 Gem 5.
In Interstellar (2014), two of the 3 terrestrial planets orbiting supermassive black hole Gargantua are proper blanets. The other one orbits a main-sequence star named Pantagruel.
References
Exoplanetology
Hypothetical planet types
Black holes
2020 neologisms | Blanet | [
"Physics",
"Astronomy"
] | 333 | [
"Black holes",
"Physical phenomena",
"Physical quantities",
"Unsolved problems in physics",
"Astrophysics",
"Density",
"Stellar phenomena",
"Astronomical objects"
] |
64,786,644 | https://en.wikipedia.org/wiki/Huawei%20AppGallery | Huawei AppGallery is a package manager and application distribution platform, or marketplace 'app store', developed by Huawei Technologies Co., Ltd. It serves as the official app store for the devices running on Huawei HarmonyOS, and is also available for Huawei EMUI and Microsoft Windows via the Mobile Engine emulator.
As of 2022, AppGallery had 580 million monthly active users.
History
Huawei AppGallery was launched in 2011 in China and in 2018 internationally.
In May 2019, Huawei was added to the Entity List by the US Department of Commerce, effectively banning the company's software products from gaining access to Google Mobile Services (GMS), Google Play Store and other such applications. As a result, Huawei began releasing its new devices with its own AppGallery, in which the apps were programmed with its own proprietary Huawei Mobile Services (HMS).
On 9 August 2019, soon after the US ban, Huawei launched HarmonyOS, first on smart TVs for Honor Vision and Vision S. In 2019 there were 45,000 Android apps using HMS on AppGallery.
During the third quarter of 2020, AppGallery had reached 350 billion app downloads. In 2020, AppGallery had 490 million users in over 170 countries and regions, On 1 March 2021, AppGallery had over 530 million active users.
Then, on 2 June 2021, Huawei launched HarmonyOS 2.0 with AppGallery pre-installed on its own smartphones and tablets. About a week later, Huawei launched a separate HarmonyOS section on its AppGallery to recommend HarmonyOS apps and compatible Android apps. Apps specifically made for HarmonyOS carried a small "HMOS" badge in the right hand corner of the app icon.
On 27 July 2022, during the HarmonyOS 3 event, Huawei revealed that the HMS ecosystem had 5.4 million global developers, up from roughly 1.6 million developers in 2020. In October 2022, AppGallery had 580 million monthly active users.
On 18 January 2024, during HarmonyOS Ecosystem development event, Huawei's President of Device Cloud announced that the HarmonyOS NEXT software system marks the second stage of development for HarmonyOS. By the end of 2024, the company expects an additional 5,000 native apps to hit on HarmonyOS AppGallery and hopes to exceed 500,000 native apps for HarmonyOS in the near future.
On 7 March 2024, it was reported that more than 4,000 apps have joined the HarmonyOS ecosystem on native .APP format apps for pre-released HarmonyOS NEXT Galaxy Edition version system on the incoming HarmonyOS 5 version, since the end of the first quarter of 2024.
On 17 April 2024, it was reported more than 5,000 native HarmonyOS apps have been built for HarmonyOS NEXT at Huawei Analyst Summit 2024 after rotating chairman confirms HarmonyOS NEXT stable version release later in the year.
On 22 April 2024, it was reported that Huawei has 1,000 apps in negotiations, alongside its 5,000 apps in total that are scheduled to be updated by planned September launch announced at HarmonyOS Developer Day HDD 2024 on 17 May 2024.
On 21 June 2024, at HDC 2024 over 1,500 native apps have already completed the HarmonyOS NEXT-based version and are available on the AppGallery for China's initial market for developer beta testers and the native app development mark reached 5000 apps for the HarmonyOS platform.
On 19 September 2024, it has been reported by Huawei that more than 10,000 apps and meta-services launched on HarmonyOS Next before commercial release in Q4.
On 16 October 2024, it has been reported by Huawei that more than 13,000 apps and meta-services launched on HarmonyOS Next before commercial release on October 22nd 2024.
Number of apps
In 2020, AppGallery had more than 96,000 apps and over 50,000 HMS-enabled apps. During Huawei's "Apps Up" event in 2021 the company announced that 134,000 apps were building on the Harmony platform (using Huawei Mobile Services). By October 2022, AppGallery had established itself as one of the world’s top app markets, with over 220,000 HMS-based Android apps.
As of 22 October 2024, it has been reported by Huawei at its official HarmonyOS Next 5 launch event that more than 15,000 apps launched on HarmonyOS platform.
See also
Google Play Store
App Store (iOS/iPadOS)
EMUI
HarmonyOS
List of Android app stores
List of mobile app distribution platforms
References
External links
AppGallery Connect — official Huawei mobile app services portal, at Huawei Developer
2011 introductions
Android (operating system)
AppGallery
Mobile software distribution platforms | Huawei AppGallery | [
"Technology"
] | 980 | [
"Mobile content",
"Mobile software distribution platforms"
] |
69,149,793 | https://en.wikipedia.org/wiki/C/2021%20T4%20%28Lemmon%29 | C/2021 T4 (Lemmon) is a long period comet discovered by the Mount Lemmon Observatory on 7 October 2021. This passage through the planetary region of the Solar System will reduce the orbital period from millions of years to thousands of years.
It has been south of the celestial equator since October 2022. On 13 June it was 1.5 degrees from magnitude 2 Beta Ceti. Closest approach to Earth was on 20 July 2023 at a distance of . The next day it reached its southernmost declination, at -56 degrees. On 25 July it passed next to the globular cluster NGC 6397. It reached perihelion on 31 July 2023 at a solar distance of 1.48 AU. The comet brightened to around apparent magnitude 8.
References
External links
Non-periodic comets
Astronomical objects discovered in 2021
Oort cloud
Discoveries by MLS
Comets in 2021
Comets in 2023 | C/2021 T4 (Lemmon) | [
"Astronomy"
] | 184 | [
"Astronomical hypotheses",
"Oort cloud"
] |
69,150,068 | https://en.wikipedia.org/wiki/Vaccine%20equity | Vaccine equity means ensuring that everyone in the world has equal access to vaccines. The importance of vaccine equity has been emphasized by researchers and public health experts during the COVID-19 pandemic but is relevant to other illnesses and vaccines as well. Historically, world-wide immunization campaigns have led to the eradication of smallpox and significantly reduced polio, measles, tuberculosis, diphtheria, whooping cough, and tetanus.
There are important reasons to establish mechanisms for global vaccine equity. Multiple factors support the emergence and spread of pandemics, not least the ability of people to travel long distances and widely transmit viruses. A virus that remains in circulation somewhere in the world is likely to spread and recur in other areas. The more widespread a virus is, and the larger and more varied the population it affects, the more likely it is to evolve more transmissible, more virulent, and more vaccine resistant variants. Vaccine equity can be essential to stop both the spread and the evolution of a disease. Ensuring that all populations receive access to vaccines is a pragmatic means towards achieving global public health. Failing to do so increases the likelihood of further waves of a disease.
Infectious diseases are disproportionately likely to affect those in low and middle-income neighborhoods and countries (LMICs), making vaccine equity an issue for local and national public health and for foreign policy. Ethically and morally, access for all to essential medicines such as vaccines is fundamentally related to the human right to health, which is well founded in international law. Economically, vaccine inequity damages the global economy. Supply chains cross borders: areas with very high vaccination rates still depend on areas with lower vaccination rates for goods and services.
Achieving vaccine equity requires addressing inequalities and roadblocks in the production, trade, and health care delivery of vaccines. Challenges include scaling-up of technology transfer and production, costs of production, safety profiles of vaccines, and anti vaccine disinformation and aggression.
Patterns of vaccine inequality
The wealthy generally have better access to vaccines than the poor, both between and within countries. Within countries, there may be lower rates of vaccination in racial and ethnic minority groups, in older adults, and among those living with disabilities or chronic conditions. The distribution and accessibility of vaccines show significant disparities between urban and rural areas especially in low- and middle-income countries. Some countries have programs to redress this inequality. Political, economic, social, and diplomatic factors can limit vaccine availability in some countries.
Factors
Achieving control of a disease (such as COVID-19) requires not only developing and licensing vaccines but also producing them at scale, pricing them so that they are globally affordable, allocating them to be available where and when they are needed, and deploying them to local communities. An effective global approach to achieving vaccine equity must address challenges in the dimensions of vaccine production, allocation, affordability, and deployment.
Doctors Without Borders (MSF) lists five major obstacles to vaccine equity, taking into account that many of those to be vaccinated are children:
Vaccine prices; new vaccines are on-patent and expensive (affordability)
Getting vaccines to children; this is expensive and gets even more difficult in conflict zones and natural disasters (affordability, deployment)
Five clinic visits in the first year of life is often too many; for people in remote areas with many children, it can be much more costly and difficult to get to a clinic. (deployment)
Keeping vaccines cold; see cold chain. (deployment)
Age-out; children who don't get vaccinated on-schedule often have to pay for their shots. Disruption from natural disasters or conflict can mean that entire generations go unprotected.(affordability, deployment)
Achieving vaccine equity depends on having a sufficient supply of affordable vaccines available for global use.
Ideally, a vaccine that is suitable for global use will be based on established technology; will have multiple available suppliers of the materials and equipment needed for production; be appropriate to the regions where it is to be produced or deployed, in terms of scalability of production and storage conditions; and be supported by local infrastructure for its production, delivery and regulation.
Vaccine development
Developing a new drug and gaining regulatory approval for it is a long and expensive process that can involve a variety of stakeholders. The time to develop a new drug can be 10 to 15 years, or longer. The average cost of developing at least one successful epidemic infectious disease vaccine from preclinical to the launch phase, taking into account the cost of failed attempts, has been estimated at from 18.1 million to US$1 billion.
Decisions about what drugs to develop reflect the priorities of the companies and countries where drug development occurs. As of 2021, the United States was the country launching the highest number of new drugs, and the country with the largest expenditure overall on pharmaceutical discovery, approximately 40% of the research done globally. The United States is also the country with the highest profits for pharmaceutical companies, and the highest drug costs for patients.
Emerging and reemerging viruses substantially affect people in low and middle income countries (LMICs), a pattern that is likely to increase due to climate change. Pharmaceutical companies have few financial incentives to develop treatments for neglected tropical diseases in poor countries.
International organizations such as the World Health Organization, Unicef and the Developing Countries Vaccine Manufacturers Network support development of treatments for diseases such as West Nile virus, dengue fever; Chikungunya, Middle East respiratory syndrome (MERS), severe acute respiratory syndrome (SARS), Ebola, enterovirus D68 and Zika virus.
Vaccine affordability
A major factor in the economics of vaccines is intellectual property law. IP currently operates by granting pharmaceutical monopolies lasting decades. The economics of monopoly power give the monopolist a strong financial incentive to use value-based pricing and set prices that many, often most, potential customers can't afford (a pricing strategy that charges what the market will bear, unlike traditional cost-plus pricing charges the cost of production plus a markup). Price discrimination attempts to charge each person the maximum they would be willing to pay, and charges every purchaser more than they would be charged in a fully-competitive market. A vaccine monopolist has no incentive to let the rich actually subsidize the poor. Medical-product monopolists may claim that the high prices charged to the rich subsidize the lower prices charged to the poor when in fact both are being charged well over independent estimates of the cost of production (see, for instance, GeneXpert cartridges and pneumococcal vaccine).
Amnesty International, Oxfam International, and Médecins Sans Frontières (MSF; Doctors without Borders) have criticized government support of some vaccine monopolies, on the grounds that the monopolies dramatically increase prices and impair vaccine equity. During the COVID-19 pandemic, there were calls for COVID-related IP to be suspended, using the TRIPS Waiver. The waiver had support from most countries, but opposition from within the EU (especially Germany), UK, Norway, and Switzerland, among others.
Vaccine production
Low and middle income countries tend to lack technological expertise and manufacturing capacity for the production of drugs and medical products. This leaves them dependent on diagnostics, treatments and vaccines from manufacturers in other countries and on availability in the global market. There are some exceptions such as China, Cuba, and India, which are actively producing pharmaceuticals to internationally accepted standards.
The COVID-19 pandemic has led to recommendations to diversify pharmaceutical production and increase the productive ability of LMICs. This could allow those countries to better ensure that their own production needs are being met, which would help to achieve global vaccine equity. For example, the African Union Commission and Africa Centres for Disease Control and Prevention has called on countries and organizations to enable the production of at least 60% of the total vaccine doses required on the continent by 2040.
Potential problems to this can involve:
Availability of capital, technology and skills
Adherence to quality standards
Inconsistent or unsupportive national and international policy frameworks
Size of markets, purchasing power, and variable demand for vaccines
Lack of national or local infrastructure (e.g. reliable energy, electricity, transportation)
Even when organizations are willing to share their information, knowledge transfer can create serious delays for the production of vaccines. This may be particularly true in the case of novel technologies. LMICs may be better situated to produce vaccines that are based on more established technologies, if those are available.
Vaccine allocation
In the absence of well-organized systems to develop and distribute vaccines,
vaccine companies and high income nations may monopolize available resources.
Organizations such as GAVI,
the Coalition for Epidemic Preparedness Innovations,
and the World Health Organization have proposed multilateral initiatives such as Covax for the improvement of vaccine allocation. The intention with Covax was to collectively pool resources to ensure vaccine development and production. The resulting vaccine supplies could be fairly distributed to reach less wealthy countries and achieve vaccine equity. Foreign aid and resources from richer countries would cover the cost of distributing doses to lower-middle and low income countries.
As an allocation mechanism, Covax has succeeded in distributing COVID-19 vaccines, beginning with a shipment to Ghana on 24 February 2021. In the next year Covax delivered 1.2 billion vaccines to 144 countries. Covax was not able to acquire doses directly from manufacturers at the levels it had hoped. An estimated that 60% of the doses it distributed in 2021 (543 million out of 910 million) were donated doses from wealthy countries, beginning with the USA (41% of all donated doses).
Covax is an unprecedented initiative, but it has not met the goal of achieving vaccine equity. Higher income nations bypassed the proposed mechanism and negotiated directly with vaccine manufacturers, leaving Covax without the resources it needed to buy and distribute vaccines in a timely fashion. Smaller and poorer countries had to wait or negotiate for themselves, with varying success. Middle income countries with finances to cover the cost of vaccines still had considerable difficulty in obtaining them.
Ideally a global vaccine hub could have been developed by the international community before it was needed, rather than under the pressures of a pandemic. Improving it is important in preparation for future health crises. Analyses of Covax' institutional design and governance structures suggest that it lacked leverage to influence the behavior of donor states and pharmaceutical companies. It has been suggested that initiatives for vaccine allocation and vaccine equity could be improved by increasing the simplicity, transparency and accountability of their mechanisms. Others argue that such a body needs high-level leadership that is able to act at political and diplomatic levels to address issues of vaccine diplomacy as well as streamlining its mechanisms.
The allocation of vaccines and the issue of wastage are related. When high income countries buy more than they use, doses go to waste. If higher income countries donate near-expiration doses to lower income countries, those doses may expire before they can be effectively reallocated and used. This type of closed vial wastage could be reduced, through the improvement of supply chain management within countries, the internationally coordinated monitoring and tracking of vaccines, and well-organized systems for the timely donation and reallocation of surplus vaccines.
Open vial wastage, which occurs when only part of a vial of vaccine is used, could also be reduced. Strategies include making less doses available in a single vial, and organizing appointments to more effectively ensure that doses are used by overbooking (since some people will not appear) or not booking (so that only those who do appear receive doses).
Vaccine deployment
Barriers to deployment may be both physical and mental. In addition to supply and demand, barriers to immunization can include systems barriers related to organization of the health care system; health care provider barriers relating to availability and education of health care staff; and patient barriers around a parent or patient's fears or beliefs about immunization.
Cheap vaccines are often not administered due to a lack of infrastructure funding.
Logistical difficulties are an obstacle to achieving global vaccine equity. Hot climates, remote regions, and low-resource settings need cheap, transportable, easy-to-use vaccines.
To achieve vaccine equity, vaccine development needs to prioritize concerns about whether a vaccine can survive outside a fridge or be administered in a single shot.
To reach communities and successfully deploy a vaccine and achieve vaccine equity, it is important to take a “human-centered” public health approach that can address and respond to the concerns of local individuals and organizations. For example, vaccines could be made available by going to where people live, and partnering with houses of worship and other community centers, rather than relying on people to travel to hospitals or doctor's offices. In Laos, measures taken included repairing roads to remote areas, buying vans with modern refrigeration to transport vaccines, and visiting residences, temples, and schools to discuss the importance of vaccination.
As part of Laos' public health campaign, President Thongloun Sisoulith was publicly vaccinated, on television, to encourage others to follow his example. Working with leaders and trusted community members within communities who can present important information and publicly identify and counter misinformation can be very successful. This type of approach was used in India, which was certified as free of poliomyelitis in 2014. In that public health campaign, 98% of the “social mobilizers” involved were women, whose involvement was critical.
Vaccine messaging
Communicating about public health risks is more effective when a message involves three or four specific talking points, which are then backed up with evidence. An initial message may focus on what is happening, what to do, and how to do it, followed up by details and how to find more information.
Part of effective communication is to avoid confusing or overwhelming people. A simple message can be followed by more complex ones. Messages should be clear about the limits of what is known: explicitly identifying the boundaries of evolving knowledge rather than speculating and sending out conflicting and confusing messages.
Often, the most useful and effective communication comes from local officials and people with expertise who know their community and the issue involved well.
It is important to be aware of and address issues such as medical disparities, abuse, neglect, and disinformation that may affect communities. Disinformation tends to thrive under conditions of confusion, distrust and disenfranchisement. Countering disinformation is not just a matter of presenting facts and figures. People need to feel heard and their concerns need to be considered.
Geographical distributions
Migrant populations
Migrants and refugees arriving and living in Europe face various difficulties in getting vaccinated and many of them are not fully vaccinated. People arriving from Africa, Eastern Europe, the Eastern Mediterranean, and Asia are more likely to be under-vaccinated (partial or delayed vaccination). Also, recently arrived refugees, migrants and seekers of asylum were less likely to be fully vaccinated than other people from the same groups. Those with little contact to healthcare services, no citizenship and lower income are also more likely to be under-vaccinated.
Vaccination barriers to migrants include language/literacy barriers, lack of understanding of the need for or their entitlement to vaccines, concerns about the side-effects, health professionals lack of knowledge of vaccination guidelines for migrants, and practical/legal issues, for example, having no fixed address. Vaccines uptake of migrants can be increased by customised communications, clear policies, community-guided interventions (such as vaccine advocates), and vaccine offers in local accessible settings.
COVID-19
Priorly developed work for other coronaviruses allowed the COVID-19 vaccination development team to have a head start, speeding up development and trials. Specifically, COVID-19 vaccination development began in January 2020. On May 15, 2020, Operation Warp Speed was announced as a partnership between the United States Department of Health and Human Services and the Department of Defense. $18 Billion was contracted out to eight different companies to develop COVID-19 vaccinations intended for the US population; major companies included where Moderna, Pfizer, and Johnson & Johnson. These three companies received the earliest emergency use approval from the FDA, therefore being the most common vaccinations in the United States.
Vaccine inequality has been a major concern in the COVID-19 pandemic, with most vaccines being reserved by wealthy countries, including vaccines manufactured in developing countries. Globally, the problem has been distribution; supply is adequate. Not all countries have the ability to produce the vaccine.
In low-income countries, vaccination rates long remained almost zero. This has caused sickness and death.
Vaccine inequity during the COVID-19 pandemic showed the disparity between minority groups and countries. Based on income and rural or urban setting, vaccination rates were vastly disproportionate. As of 19 March 2022, 79% of people in high income countries had received one or more doses of a COVID-19 vaccine, compared with just 14% of people in low income countries. By April 25, 2022, 15.2% of people in low income countries had received at least one dose, while overall globally 65.1% of the global population had received at least one dose.
Throughout the data of COVID-19 vaccination records, rates have consistently been much lower for lower income groups than that of middle and higher income groups. COVID-19 vaccination rates are higher in urban settings, and lower in rural settings. In an underdeveloped country such as Nigeria, vaccination rates are under 11% nationally. Because of persistent vaccine inequity, many countries continue to not have access to free or affordable COVID-19 vaccinations.
Our World in Data provides up to date statistics of COVID-19 vaccine access between nations, socioeconomic groups, and more.
In September 2021, it was estimated that the world would have manufactured enough vaccines to vaccinate everyone on the planet by January 2022. Vaccine hoarding, booster shots, a lack of funding for vaccination infrastructure, and other forms of inequality mean that it is expected that many countries will still have inadequate vaccination.
On August 4, 2021, the United Nations called for a moratorium on booster doses in high-income countries, so that low-income countries can be vaccinated. The World Health Organization repeated these criticisms of booster shots on the 18th, saying "we're planning to hand out extra life-jackets to people who already have life-jackets while we're leaving other people to drown without a single life jacket". UNICEF supported a "Donate doses now" campaign.
On 29 January 2022, Pope Francis denounced the "distortion of reality based on fear" that has ripped across the world during the COVID-19 pandemic. He urged journalists to help those misled by coronavirus-related misinformation and fake news to better understand the scientific facts.
See also
Economics of vaccines
Vaccine resistance
GAVI
COVAX
CEPI
Developing Countries Vaccine Manufacturers Network
References
Vaccination
Public health
Health equity | Vaccine equity | [
"Biology"
] | 3,935 | [
"Vaccination"
] |
69,150,103 | https://en.wikipedia.org/wiki/Christa%20Muller-Sieburg | Christa Edith Muller-Sieburg (19 February 1952 – 12 January 2013) was a German-American immunologist and hematologist, whose work became central to the understanding of the clonal heterogeneity of hematopoietic stem cells (HSCs). Muller-Sieburg is known for her contributions to the purification of hematopoietic stem cells, the characterization of individual stem cell clones and her revision of the process of hematopoiesis.
Muller-Sieburg was a co-discoverer of the negative marker set of hematopoietic stem cells that led to the modern purification techniques widely used in hematopoietic stem cell research today. She was the first to demonstrate the biased differentiation behavior of individual stem cell clones, thereby sparking a novel and entirely original view of hematopoiesis.
Biography
Muller-Sieburg received her Abitur in 1972 in Bonn, West Germany. The same year, she moved to Köln to begin her studies in biology at the University of Cologne. She completed her studies under the guidance of Klaus Rajewsky in 1978 with a diploma thesis in immunology entitled "Investigations concerning the Class Specificity of the Fc-Receptor on Murine Lymphocytes Using Monoclonal Antibodies" at the Institut für Genetik. She received her doctorate in the natural sciences in 1983 with a dissertation entitled "Regulation of the Expression of Idiotopic Antibodies by Isotype Variants of Monoclonal Anti-Idiotopic Antibodies" (advisor: Klaus Rajewsky).
Muller-Sieburg married Hans B. Sieburg, a mathematician whom she had met in 1972 while studying at the University of Cologne.
Muller-Sieburg died on 12 January 2013 of a squamous cell carcinoma, after nine years of illness, during which time she was still actively working.
Academic career
In 1983, Muller-Sieburg and her husband, Hans B. Sieburg, moved to the United States of America, both as fellows of the Deutsche Forschungsgemeinschaft (German Research Foundation) at Stanford University. There, Muller-Sieburg began her research at the laboratory of Irving Weissman at the Stanford University Medical Center, while H. Sieburg worked and taught at the Stanford Mathematics Department.
Muller-Sieburg's research at Weissman's lab was focused on the identification of a common cell precursor for both T cells and B cells. She worked closely with Cheryl Ann Whitlock, who came to Weissman's lab from Owen Witte's lab also to work on the B cell precursor problem. The results of their collaboration were reported in a joint paper, describing for the first time the isolation of an early committed pre-pre-B cell along with the discovery of a hematopoietic stem cell population expressing low levels of Thy-1 antigen. The marker Thy-1(low) was crucial to establishing the exclusion criteria for the purification of HSCs.
In 1986, Muller-Sieburg and her husband moved to La Jolla, California, where she continued her work on the characterization and maintenance of hematopoietic stem cells at the Eli Lilly Research Institute led by Dr. Jacques M. Chiller, while Hans Sieburg initially joined the laboratory of Melvin Cohn at the Salk Institute for Biological Studies and later, became faculty at the University of California, San Diego.
In 1989, Muller-Sieburg became an independent group leader at the Medical Biology Institute in La Jolla, where she expanded her work on the purification and maintenance of hematopoietic stem cells via long-term bone marrow cultures – a technique she had developed in collaboration with Cheryl Whitlock, George F Tidmarsh and Irving Weissman at Stanford. By using this technique, Muller Sieburg and Elena Deryugina identified the growth factor, namely macrophage-colony stimulating factor (M-CSF) as a cytokine critical for the maintenance of stromal cell support for hematopoietic stem cells.
Muller-Sieburg's recognition as a leading scientist in the field of experimental hematology, led to her appointment as a professor and head of the stem cell program at the Sidney Kimmel Cancer Center, La Jolla in 1998, and, subsequently, as a professor at the Sanford Burnham Medical Research Institute (later: Sanford Burnham Prebys), from 2009 until her death.
During her research career Muller-Sieburg published more than 50 articles in peer-reviewed journals, wrote several invited book chapters, and co-authored one book on hematopoietic stem cells.
Muller-Sieburg was frequently invited to national and international conferences and symposia. Muller-Sieburg gave her last invited lecture "The Life of a Hematopoietic Stem Cell" at the Keystone Symposium "The Life of a Stem Cell: From Birth to Death" in March 2012. In 2013, the Christa Muller-Sieburg award was named after her by the International Society of Experimental Hematology.
Research
Immunology
While working at the University of Cologne, Muller-Sieburg addressed a key element of idiotype network theory postulated by Niels Kaj Jerne, namely the enigmatic shift from one to another class of immunoglobulins produced by the same clone on B-lymphocytes. By making sequential sub-lines from an original hybridoma line, she discovered immunoglobulin class switch and described it in her 1983 paper published with Klaus Rajewsky. The following year, they co-authored an important paper on the regulation of the isotype switch by anti-idiotype antibodies. This ground-breaking paper was recognized and cited by Niels K. Jerne in his Nobel Prize acceptance lecture on 8 December 1984.
Hematology
Purification of hematopoietic stem cells
Muller-Sieburg accomplished separation of whole bone marrow into two fractions, the adherent and non-adherent fractions, and demonstrated that the latter fraction was the one that comprised B cell precursors. She found that it was not the B220-positive fraction that contained B-cell precursors as was expected, but the B220-negative fraction. She confirmed that B220+ cells were too late in the lineage to make B cells let alone T cells and myeloid cell types. Importantly, this B220-negative population was enriched for cells that were capable of reconstituting all types of blood cells for life when transplanted into lethally irradiated hosts ("complete repopulation capacity"). Complete repopulation capacity is the property which distinguishes hematopoietic stem cells from all other blood cell types. For their work on hematopoietic stem cell purification, Muller-Sieburg and collaborators were awarded a United States patent.
Genetic control of stem cell frequency
Muller-Sieburg was one of the first to recognize the need of maintaining HSC multi-lineage and self-renewal potentials while propagating HSCs in vitro. A sequence of publications in the 1990s established Muller-Sieburg as a pioneer of stromal-stem cell culture methodology. In the course of this work, Muller-Sieburg noticed that the frequency of HSCs - a measure of proliferative capacity - is under genetic control. In a 1996 landmark study, she and collaborators reported the discovery of the hematopoietic stem cell frequency gene on chromosome 1 in the murine system, which they named Scfr1 (stem cell frequency regulator 1). In a follow-up study in 2000, Muller-Sieburg and co-workers showed that the genetic control of HSC frequency is mostly cell-autonomous. By 2008, Scfr1 had become integrated into the group of genes and gene networks that specify "stemness" and cell fate decisions.
Heterogeneity of the hematopoietic stem cell population
The last 15 years of her life, Muller-Sieburg worked on the clonal fabric of hematopoiesis, making pioneering contributions to the foundations and practice of the science of blood. Based on her 1996 studies of the heterogeneity of the hematopoietic microenvironment, Muller-Sieburg increasingly doubted the then pervasive belief that "all stem cells are created equal", a view that, if true, would imply that blood is mono-clonal. To gain clarity, she followed the kinetics of individual HSCs and showed that blood generated by one individual hematopoietic stem cell differs significantly from the blood of another individual HSC by (a) the lifespan of the underlying stem cell population and (b) the composition by blood cell types relative to each other. Her discovery demonstrated that, in fact, the opposite of the dogmatic view of stem cell homogeneity is the case. Namely, she showed that whole blood is the poly-clonal mixture of the hematopoietic systems generated and maintained by individual stem cells actively functioning during any given period of time.
These results that whole blood is composed of many individual bloods were obtained by single-cell experiments using limiting dilution for cell sorting and serial transplantation. In this approach, an initial transplant containing one hematopoietic stem cell extracted from lineage negative (Lin-) blood cells is used to rescue a lethally irradiated host with mono-clonal blood. The results from these serial transplantation experiments, lasting from 7 months up to five years, led Muller-Sieburg to quantitatively analyze sets of stem cell kinetics with H. Sieburg. These analyses led to the discovery of quantitative determinants of clonal heterogeneity and the confirmation of Muller-Sieburg's conjecture that specific purification methods might restrict the repertoire of purified HSC, emphasizing that caution be taken in interpreting experimental results from a specific set of HSCs to be true for all HSCs This work laid the clonal foundations of modern hematology.
Quantitative determinants of clonal heterogeneity
Based on her experimental data, Muller-Sieburg suggested to replace the dogmatic view of the homogeneity of the stem cell population with the new concept of clonal diversity within the population of hematopoietic stem cells. She showed that the heterogeneity of the differentiation potential of adult hematopoietic stem cells is epigenetically fixed before birth and that no new heterogeneity of differentiation potential is introduced by self-renewal in postnatal hematopoiesis. Muller-Sieburg showed definitively that, therefore, an organism's blood is the mixture of blood cells contributed by distinct hematopoietic stem cell clones during the organism's lifetime. The process of blood formation (hematopoiesis) acts on the fixed repertoire of heterogeneous stem cell clones.
Clonal lifespan
According to the dogmatic view of stem cell homogeneity the lifespan of individual HSCs (defined as the time period for which an HSC can divide without differentiation) was assumed to be approximately the same. However, Muller-Sieburg experiments demonstrated that the longevity of hematopoietic stem cell clones differed dramatically. Specifically, she showed that clonal bloods became deficient in one or more cell types – a definitive observable of the extinction of their clone-maintaining stem cell population – after significantly different lengths of time. Some of these clone-maintaining hematopoietic stem cells survived multiple sequential in vitro-in vivo transplantations, which exceeded several times the normal life expectancy of the host. These results allowed Muller-Sieburg to establish the clonal lifespan as a quantitative measure of the reliability of self-renewal capacity.
At the same time, consistent with clonal heterogeneity, she showed that the differentiation capacity of individual HSCs is (a) limited and (b) dependent on the clone founder. Therefore, Muller-Sieburg also established the variability in differentiation capacity as a quantitative measure of clonal heterogeneity and clonal lifespan.
Furthermore, Muller-Sieburg's clonal experiments showed that the life of a hematopoietic stem cell (clone) is highly dependent on the initial conditions given by the epigenetically fixed differentiation and self-renewal capacities of each clone founding HSC.
Lineage bias
Muller-Sieburg showed that murine hematopoietic stem cells form a heterogeneous cell population with respect to their differentiation and proliferation behaviors. As a consequence of this clonal heterogeneity principle, whole blood represents as a mixture of "bloods" originating from many active stem cell clones. Within each clonal blood, all HSCs form a homogeneous core population whose members have the same lifespan and carry the memory of the differentiation and self-renewal capacities of the founder HSC. By comparing the intra-clonal kinetics of the leukocyte sub-populations, Muller-Sieburg showed that all hematopoietic stem cells belong to and stay for life in one of three classes of repopulation kinetics: Myeloid-biased (My-bi), Balanced or Lymphoid-biased (Ly-bi). Thus, an unexpected organization of HSC differentiation behaviors was discovered, leading to the principle of lineage bias established by Muller-Sieburg in collaboration with Hans Sieburg.
Deterministic regulation of hematopoiesis
Most theories of hematopoiesis assume that self-renewal and differentiation of hematopoietic stem cells (HSCs) are randomly regulated by intrinsic and environmental influences. Opposite to this "stochastic" view, Muller-Sieburg showed that random regulation is incompatible with the evidence of clonal hematopoiesis involving the heterogeneous core populations of HSCs. Specifically, her data argue that self-renewal does not contribute to the heterogeneity of the adult HSC compartment but, rather, all HSCs in a clone follow a predetermined fate, consistent with the generation-age hypothesis. By extension, the self-renewal and differentiation behavior of HSCs in adult bone marrow is more predetermined than stochastic. Almost a decade later, in a review paper, Timm Schroeder summarized these essential findings in the succinct phrase "subtypes, not unpredictable behavior". The dependence on epigenetically determined initial conditions placed hematopoiesis mathematically into the category of chaotic systems with deterministic evolution. This view was supported by Muller-Sieburg's finding in collaboration with H. Sieburg that the clonal lifespan of HSCs can be predicted from repopulation kinetics. Muller-Sieburg's experimental work, therefore, establishes hematopoiesis as a new highly non-trivial challenge in chaos theory.
A new theory of hematopoietic aging
Muller-Sieburg expanded her clonal studies to explore the correspondence between the long-term limit behavior of the hematopoietic process and the longevity of the host organism. Specifically, she wondered about the possible dualism of "aged organism" and "old HSCs". Following her own, strict biological definition of HSC aging as intrinsic to the hematopoietic system, she showed that the answer to the dualism problem lies in the long-term dynamics of clonal aging of individual HSCs in the context of the clonal composition of an aging hematopoietic system.
The clonal analysis of repopulating HSCs demonstrated that lymphoid-biased (Ly-bi) HSCs are lost earlier compared to the longer-lived myeloid-biased HSCs, which accumulate in the aged organism. Importantly, myeloid-biased (My-bi) HSCs from young and aged sources behave similarly in all aspects tested, indicating that organism aging does not change individual HSCs. Rather, aging (defined as "the totality of observable effects in an entity surviving in the long-term time limit relative to the behavior of the same observables at earlier times") changes the clonal composition of the HSC population, as manifested in the shift in bias classes of HSCs. Specifically, the proportion of the myeloid-biased HSCs is increased compared to the proportion of lymphoid-biased HSCs, while the proportion of balanced HSCs is near unchanged. This important conclusion may have significant implications to understanding the causes of the age-related immune deficiencies.
Computational research of hematopoiesis
Muller-Sieburg was an early adopter and promoter of the use of abstract mathematics in the field of experimental hematology. In collaboration with Hans Sieburg, this approach proved particularly fruitful in her experimental studies of HSC clonality. For example, the classification of kinetics or the prediction of lifespans from short initial kinetics or the reliability of self-renewal required symbolic computation, reliability theory and functional programming. Muller-Sieburg generously provided data for other modeling studies and engaged in correspondence discussions of deep principles of modeling hematopoiesis. The important outcomes of Muller-Sieburg's clonal diversity experiments are time-series, which are invaluable in computational research addressing one of the central open problems in hematopoiesis research, namely HSC “fate decisions". In vivo, at multiple million cell scales, "fate decisions" must occur reasonably fast and reliably to uphold all blood functions for extended periods of time. Muller-Sieburg's work showed that hematopoietic "decisions" occur on a largely deterministic basis, which is consistent with the demands for speed and reliability expected for host survival.
References
External links
Christa Muller-Sieburg funding history and related publications, grantome.com
Christa Muller-Sieburg award, International Society of Experimental Hematology
1952 births
2013 deaths
Women immunologists
Women hematologists
University of California, San Diego faculty
University of Cologne alumni
Deaths from cancer in California
21st-century American biologists
American medical academics
Stem cell researchers
American people of German-Jewish descent
20th-century women scientists | Christa Muller-Sieburg | [
"Biology"
] | 3,771 | [
"Stem cell researchers",
"Stem cell research"
] |
69,151,671 | https://en.wikipedia.org/wiki/Needle%20spiking | Needle spiking (also called injection spiking) is a phenomenon initially reported in the UK and Ireland where people have reported themselves subjected to surreptitious injection of unidentified sedative drugs, usually in a crowded environment such as the dancefloor of a nightclub, producing symptoms typical of date rape drugs. A Home Affairs Committee report noted a lack of motive in respect of needle spiking. In 692 incidents recorded in the last three months of 2021, there was only one claimed further offence of sexual offending or robbery.
No verified toxicological results have been published showing the presence of known incapacitating agents in alleged victims; the prevalence of genuine cases is unknown and has been controversial, with experts expressing doubts as to how easily such injections could be carried out without it being immediately obvious to the victim and attributing the reports to hysteria. Dr Emmanuel Puskarczyk, head of the poison control centre at the , when noting the absence of objective proof has stated that the administration of a substance would require several seconds meaning that the recipient would likely notice at the time.
Reports
UK
1,032 reported claims of spiking by injection were recorded from the beginning of September to the end of December 2021. In Nottingham, where 15 reports of needle spiking were made in October, police identified only one case where a victim's injury "could be consistent with a needle". In November that year, there followed reports in Brighton and Eastbourne; and it was reported that two women alleged they had been spiked with needles inside a Yorkshire nightclub. In Northern Ireland, the PSNI began an investigation after a woman believed she was spiked with a needle in Omagh on 6 November 2021.
In December 2021, Nottinghamshire Police Service had received 146 reports of suspected needle spiking. Nine arrests were made but no suspects were subsequently charged. VICE News were informed by the National Police Chiefs' Council (NPCC) of 274 reported cases between September-November 2021 in the UK. The NPCC said that no cases of injection of drugs had been confirmed, and that there was one confirmed case of "needle-sticking", involving someone being jabbed, but not necessarily injected, with a needle; investigations were continuing to determine whether the needle contained any spiking drugs.
Despite the allegations, there has not been a single prosecution from needle spiking in the UK. Furthermore, experts from the scientific and academic community have claimed the likelihood of being spiked by injection is extremely low. Prof Adam Winstock, a trained consultant psychiatrist from the Global Drugs Survey, explained that “Needles have to be inserted with a level of care […] The idea these things can be randomly given through clothes in a club is just not that likely."
France
Since the summer of 2021, over 100 cases of needle spiking have been reported in French nightclubs. In May 2022, the Ministry of the Interior commented that it had found the majority of those reporting incidents had been injected with something; their spokesman said, "Too often the absence of traces detected cannot be interpreted as the absence of an injection, but as sampling too late."
Ireland
In Ireland, the Garda Síochána carried out multiple needle spiking investigations in October and November 2021. The first known report of claimed needle spiking in Ireland was on 27 October 2021, when a woman claimed she was spiked with a needle in a Dublin nightclub.
Belgium
There has been an incident of needle spiking of football supporters in May 2022 during a match between KV Mechelen and Racing Genk. Fourteen soccer fans from the same section of the stadium felt a prick and subsequently became unwell, although initial toxicological reports found nothing.
Also in May 2022, in the city of Hasselt (Limburg), twenty-four youngsters became unwell at teen festival We R Young after what may have been needle spiking or mass hysteria.
Germany
In May 2022, Australian musician Zoè Zanias of Linea Aspera claimed she was attacked in a needle-spiking at the Berghain nightclub in Berlin, suffering from respiratory depression and an unwanted "psychedelic" experience as a result.
Spain
As of summer 2022, the Spanish police have registered 23 cases in Catalonia and 12 in the Basque Country. No traces of drugs were detected and there were no cases of related sexual violence.
Switzerland
On 13 August 2022 the Street Parade, a large open air rave event with hundreds of thousands of participants, took place in Zurich. A total of 8 female attendees contacted first aid services claiming needle spiking attacks. One of the victims, a 16 year old girl, was allegedly spiked 14 times.
Australia
On April 24, 2022, a woman claimed she was spiked at a Melbourne nightclub.
Reactions
Concerns have been raised by campaigners, politicians and student bodies. In October 2021 it was reported that British home secretary Priti Patel had requested police forces investigate the alleged incidents. In December that year, the Home Affairs Select Committee launched a new inquiry into spiking, including needle spiking, and the effectiveness of the police response to it.
In Ireland, Young Fine Gael drafted a bill, which Fine Gael members introduced in Seanad Éireann in July 2023, "to provide for the specific offence of spiking characterised by the administration, injection, or causation of the taking orally of a substance, knowing that the person to whom the substance is administered, injected, or caused to be taken does not consent, or being reckless as to whether the person consents, and where the perpetrator intends to overpower or sedate the person, to engage in a sexual act, cause harm, make a gain or cause a loss, or otherwise commit an offence."
Boycotts and tougher checks
In response, a number of women from university cities decided to boycott nightclubs for "girls' nights in". Campaigners also called on nightclubs to impose tougher checks on entry; an online petition on the issue was considered by Parliament on 4 November 2021, where it was decided no changes to the law should be made.
See also
Drink spiking
Needlestick injury
Pin prick attack
References
Assault
Crimes
Incapacitating agents
October 2021 crimes in Europe
November 2021 crimes in Europe
September 2021 crimes in Europe | Needle spiking | [
"Chemistry"
] | 1,277 | [
"Incapacitating agents",
"Chemical weapons"
] |
69,152,704 | https://en.wikipedia.org/wiki/Digital%20Building%20Logbook | The Digital Building Logbook is a proposal aiming at establishing a common European approach that aggregates all relevant data about a building and ensures that authorised people can access accurate information about the building.
See also
Energy performance certificate
Building information modeling
References
Building engineering
Building information modeling | Digital Building Logbook | [
"Engineering"
] | 53 | [
"Building engineering",
"Building information modeling",
"Civil engineering",
"Architecture"
] |
69,153,451 | https://en.wikipedia.org/wiki/History%20of%20the%20lithium-ion%20battery | This is a history of the lithium-ion battery.
Before lithium-ion: 1960-1975
1960s: Much of the basic research that led to the development of the intercalation compounds that form the core of lithium-ion batteries was carried out in the 1960s by Robert Huggins and Carl Wagner, who studied the movement of ions in solids. In a 1967 report by the US military, plastic polymers were already used as binders for electrodes and graphite as a constituent for both cathodes and anodes, mostly for cathodes.
1970s: Reversible intercalation of lithium ions into graphite as anodes and intercalation of lithium ions into cathodic oxide as cathodes was discovered during 1974–76 by Jürgen Otto Besenhard at TU Munich. Besenhard proposed its application in lithium cells. What was missing in Besenhard's batteries is a solvent showing no co-intercalation into graphite, electrolyte decomposition and corrosion of current collectors. Thus, his batteries had very short cycle lives.
1970s: Reversible intercalation of lithium ions into layered cathode materials. British chemist M. Stanley Whittingham, then a researcher at ExxonMobil, first reported a charge-discharge cycling with a lithium metal battery (a precursor to modern lithium-ion batteries) in the 1970s. Drawing on previous research from his time at Stanford University, he used a layered titanium(IV) sulfide as cathode and as anode. However, this setup proved impractical. Titanium disulfide was expensive (~$1,000 per kilogram in the 1970s) and difficult to work with, since it has to be synthesized under completely oxygen- and moisture-free conditions. When exposed to air, it reacts to form hydrogen sulfide compounds, which have an unpleasant odour and are toxic to humans and most animals. For this, and other reasons, Exxon discontinued development of Whittingham's lithium-titanium disulfide battery.
Batteries with metallic lithium electrodes presented safety issues,
most importantly the formation of lithium dendrites, that internally short-circuit the battery resulting in explosions. Also, dendrites often lose electronic contact with current collectors leading to a loss of cyclable Li+ charge.
Consequently, research moved to develop batteries in which, instead of metallic lithium, only lithium compounds are present, being capable of accepting and releasing lithium ions.
1973: Adam Heller proposed the lithium thionyl chloride battery, still used in implanted medical devices and in defense systems where a greater than 20-year shelf life, high energy density, and/or tolerance for extreme operating temperatures are required. However, this battery employs unsafe lithium metal and was not rechargeable.
Precommercial development: 1974-1990
1974: Besenhard was the first to show reversibility of Li-ion intercalation into graphite anodes, using organic solvents, including carbonate solvents.
1976: Stanley Whittingham and his colleagues at Exxon demonstrated what can be considered the first rechargeable "lithium-ion battery", although not a single component in this design was used in commercial lithium-ion batteries later. Whittingham's cell was assembled in a charged state using lithium aluminum alloy as the negode, LiBPh4 (lithium tetraphenylborate) in dioxolane as the electrolyte and TiS2 as the posode. The battery useful cycle life was no more than 50 cycles. This design was based on Whittigham's earlier Li-metal batteries.
1977: Samar Basu et al. demonstrated irreversible intercalation of lithium in graphite at the University of Pennsylvania. This led to the development of a workable lithium intercalated graphite electrode at Bell Labs in 1984 () to provide an alternative to the lithium metal electrode battery. However it was only a molten salt cell battery rather than a lithium-ion battery.
1978: Michel Armand introduced the term and a concept of a rocking-chair battery, where the same type of ion is de/intercalated into both positive and negative electrode during dis/charge. In the rocking-chair design solution-phase species do not appear in the reaction stoichiometry, which allows for minizing the amount of solvent in the battery, reduces the battery weight and cost.
1979: Working in separate groups, Ned A. Godshall et al., and, shortly thereafter, John B. Goodenough (Oxford University) and Koichi Mizushima (Tokyo University), demonstrated limited discharge-charge cycling of a 4 V cell made with lithium cobalt dioxide () as the positive electrode and lithium metal as the negative electrode. This innovation provided the positive electrode material, which eventually became a component in the first commercial rechargeable lithium-ion battery. is a stable positive electrode material which acts as a donor of lithium ions, which means that it can be used with a negative electrode material other than lithium metal. By enabling the use of stable and easy-to-handle negative electrode materials, enabled novel rechargeable battery systems. Godshall et al. further identified the similar value of ternary compound lithium-transition metal-oxides such as the spinel LiMn2O4, Li2MnO3, LiMnO2, LiFeO2, LiFe5O8, and LiFe5O4 (and later lithium-copper-oxide and lithium-nickel-oxide cathode materials in 1985) Godshall et al. patent for the use of LiCoO2 as cathodes in lithium batteries was based on Godshall's Stanford University Ph.D. dissertation and 1979 publications.
1980: M.Lazzari and Bruno Scrosati at the University of Rome validated the concept of rocking-chair battery using lithium tungsten dioxide as the anode, titanium disulfide as the cathode and lithium perchlorate in propylene carbonate as the electrolyte.
1980's: The negative electrode has its origins in PAS (polyacenic / polyacetylene semiconductive material) discovered by Tokio Yamabe and later by Shizukuni Yata in the early 1980s. This development was inspired by an earlier discovery of conductive polymers by Professor Hideki Shirakawa and his group, and it could also be seen as having started from the polyacetylene lithium-ion battery developed by Alan MacDiarmid and Alan J. Heeger et al.
1983: Rachid Yazami demonstrated the reversible electrochemical intercalation of lithium in graphite at room temperature using polyethylene oxide solvent. The organic battery solvents, known at the time, decompose during charging with a graphite negative electrode. For this reason, Yazami used a solid electrolyte to demonstrate that lithium could be reversibly intercalated into graphite via an electrochemical mechanism at room temperature.
1983: Michael M. Thackeray, Peter Bruce, William David, and John B. Goodenough developed manganese spinel, Mn2O4, as a charged cathode material for lithium-ion batteries. It has two flat plateaus on discharge, with lithium one at 4 V, stoichiometry LiMn2O4, and one at 3 V with a final stoichiometry of Li2Mn2O4.
1985: Akira Yoshino demonstrated a rechargeable Li-ion battery using carbonaceous material (acetylene black), into which lithium ions could be inserted, as the negative electrode (anode) and lithium cobalt oxide () as the positive electrode (cathode). This dramatically improved safety and prepared Sony for commercial launch of a rechargeable lithium-ion battery 5 years later. Yoshino's design in 1985 was different from the final (1990) design in using 0.6 mol of LiClO4 (rather than LiPF6) in propylene carbonate (without ethylene or linear carbonate used currently to passivate the graphite negode) and in using polyacrylonitrile rather than polyvinylidene difluoride as the binder.
1986 : Around the same time as Akira Yoshino, Auborn and Barberio at Bell Laboratory independently demonstrated another true rocking-chair battery assembled in the fully discharged state. Their 1.8 V lithium-ion battery comprised LiCoO2 as the posode, 1M LiPF6 in propylene carbonate as the electrolyte and MoO2 as the negode.
1986 : Asahi researchers, led by Akira Yoshino, demonstrated rechargeable battery with lithium tetrafluoroborate (LiBF4) dissolved in a mixture of PC, gamma-butyrolactone (γBL) and ethylene carbonate (EC), as the electrolyte. The fluorinated anion turned out to be effective in passivating the Al current collector and compatible with the solvents, while ethylene carbonate (which is solid at room temperature and is mixed with other solvents to make a liquid) provided th necessary solid electrolyte interphase on the anode, thus publicly disclosing the final piece of the puzzle leading to the modern lithium-ion battery. This design was practically identical (except for LiBF4 being replaced with LiPF6, which is less reactive with the solvent(s)) to the one used in commercial lithium-ion batteries today.
1987-1989: Arumugam Manthiram and John B. Goodenough discovered the polyanion class of cathodes. They showed that positive electrodes containing polyanions, e.g., sulfates, produce higher voltages than oxides due to the inductive effect of the polyanion. This polyanion class contains materials such as lithium iron phosphate.
1989:The recall of Moli Energy cells, comprising lithium metal, abruptly changed researchers’ perception in favor of heavier but safer dual-intercalation (i.e. lithium-ion rather than lithium-metal) batteries.
1989-10-11: Jeff Dahn and two colleagues at Moli Energy in Burnaby (Canada) submit a journal article, proving a reversible intercalation of lithium ions into graphite in the presence of ethylene carbonate solvent (in 50:50 mixture with propylene carbonate and with 1M LiAsF6 salt), and demonstrating the formation of solid electrolyte intephase on the first charge, followed by a reversible battery cycling. This is essentially the composition, which will be used in commercial Li-ion batteries since 1992, except for LiAsF6 having been replaced with cheaper and less toxic LiPF6.
1990: Rachid Yazami at the French National Centre for Scientific Research in Grenoble, France starts collaborating with Sony on developing graphite anode and liquid electrolyte for lithium-ion batteries, eventually discovering the magic ethylene carbonate solvent, which resulted in almost doubling (to 155 Wh/kg) the specific energy of cells with soft carbon anodes.
1990-12-10: Sanyo Electric of Japan files a patent application, that describes a rechargeable (ca. 250 cycles) lithium metal battery with a mixed ethylene carbonate + dimethyl carbonate solvent and LiPF6 as the electrolyte.
1990: The English term "lithium-ion battery", which was invented as a marketing tool to distinguish the new technology from ill-fated lithium metal batteries appeared for the first time in a publication. It was used by Sony employees.
In 2017 (2 years before the 2019 Nobel Prize in Chemistry was awarded) George Blomgren offered some speculations on why Akira Yoshino's group produced a commercially viable lithium-ion battery before Jeff Dahn's group:
The Dahn group tested the carbonaceous positive electrode against lithium instead of a metal oxide. Therefore, they did not observe the severe corrosion of an aluminum positive current collector with the LiAsF6 electrolyte, but Yoshino et al. used ... LiPF6, which was commonly used for primary lithium metal batteries in Japan.
Yoshino et al. also studied various binders including the ultimate winner- polyvinylidene fluoride, while Dahn's group used only ethylene propylene diene monomer (EPDM), which turned out to be not durable enough for commercial LIBs.
Commercialization in portable applications: 1991-2007
The performance and capacity of lithium-ion batteries increased as development progressed.
1991: Sony and Asahi Kasei started commercial sale of the first rechargeable lithium-ion battery. The Japanese team that successfully commercialized the technology was led by Yoshio Nishi. 1991 ushered the Second Period (commercialization) in the history of lithium-ion batteries, which is reflected as inflection points in the plots "The log number of publications about electrochemical powersources by year" and "The number of non-patent publications about lithium-ion batteries" shown on this page. The battery employed soft carbon (rather than graphite) anode and LiCoO2 cathode. Sony's success with the development of lithium-ion battery manufacturing benefited from the company's prior experience with manufacturing monodisperse (20 μm) metal oxide microparticles and with coating processes for magnetic tapes.
1994: iconectiv First commercialization of Li polymer by Bellcore.
1994: The first aqueous Li-ion “rocking chair” chemistry was demonstrated by Dahn et al. It had a VO2 anode and LiMn2O4 cathode in a 5 M LiNO3 electrolyte with 1 mM LiOH.
1996: Goodenough, Akshaya Padhi and coworkers proposed lithium iron phosphate () and other phospho-olivines (lithium metal phosphates with the same structure as mineral olivine) as positive electrode materials.
1996: Sony and Nissan announced a partnership to develop a lithium-ion battery powered car FEV II with a 124 mile driving range.
1998: C. S. Johnson, J. T. Vaughey, M. M. Thackeray, T. E. Bofinger, and S. A. Hackney report the discovery of the high capacity high voltage lithium-rich NMC cathode materials.
2001: Arumugam Manthiram and co-workers discovered that the capacity limitations of layered oxide cathodes is a result of chemical instability that can be understood based on the relative positions of the metal 3d band relative to the top of the oxygen 2p band. This discovery has had significant implications for the practically accessible compositional space of lithium-ion battery layered oxide cathodes, as well as their stability from a safety perspective.
2001: Christopher Johnson, Michael Thackeray, Khalil Amine, and Jaekook Kim file a patent for lithium nickel manganese cobalt oxide (NMC) lithium rich cathodes based on a domain structure.
2001: Zhonghua Lu and Jeff Dahn file a patent for the NMC class of positive electrode materials, which offers safety and energy density improvements over the widely used lithium cobalt oxide.
2002: Yet-Ming Chiang and his group at MIT showed a substantial improvement in the performance of lithium batteries by boosting the LiFePO4 material's conductivity by doping it with aluminium, niobium and zirconium. The exact mechanism causing the increase became the subject of widespread debate.
2004: Yet-Ming Chiang again increased performance by utilizing lithium iron phosphate particles of less than 100 nanometers in diameter. This decreased particle density almost one hundredfold, increased the positive electrode's surface area and improved capacity and performance. Commercialization led to a rapid growth in the market for higher capacity lithium-ion batteries, as well as a patent infringement battle between Chiang and John Goodenough.
2004: The number of non-patent publications about lithium-ion batteries from PR China surpassed that from the USA. Japan was the third leading country till 2011, when it was surpassed by South Korea.
2005: Y Song, PY Zavalij, and M. Stanley Whittingham report a new two-electron vanadium phosphate cathode material with high energy density
Commercialization in automotive applications: 2008-today
2008: The launch of Tesla Roadster- the first highway legal, serial production, all-electric car to use lithium-ion battery cells, and the first production all-electric car to travel more than 244 miles (393 km) per charge- ushered a new era in the history of Li-ion batteries, which is signified as inflection points in the plots "The log number of publications about electrochemical powersources by year" and "The number of non-patent publications about lithium-ion batteries" shown on this page.
2011: Lithium nickel manganese cobalt oxide (NMC) cathodes, developed at Argonne National Laboratory, are manufactured commercially by BASF in Ohio.
2011: Lithium-ion batteries accounted for 66% of all portable secondary (i.e., rechargeable) battery sales in Japan.
2012: John Goodenough, Rachid Yazami and Akira Yoshino received the 2012 IEEE Medal for Environmental and Safety Technologies for developing the lithium-ion battery.
2014: John Goodenough, Yoshio Nishi, Rachid Yazami and Akira Yoshino were awarded the Charles Stark Draper Prize of the National Academy of Engineering for their pioneering efforts in the field.
2014: Commercial batteries from Amprius Corp. reached 650 Wh/L (a 20% increase), using a silicon anode and were delivered to customers.
2016: Koichi Mizushima and Akira Yoshino received the NIMS Award from the National Institute for Materials Science, for Mizushima's discovery of the LiCoO2 cathode material for the lithium-ion battery and Yoshino's development of the lithium-ion battery.
2016: Z. Qi, and Gary Koenig reported a scalable method to produce sub-micrometer sized using a template-based approach.
2019: The Nobel Prize in Chemistry was given to John Goodenough, Stanley Whittingham and Akira Yoshino "for the development of lithium ion batteries".
2022: Battery startup SPARKZ announced plans to convert a glass plant in Bridgeport, WV to produce zero-cobalt lithium batteries.
Market
Industry produced about 660 million cylindrical lithium-ion cells in 2012; the 18650 size is by far the most popular for cylindrical cells. If Tesla were to have met its goal of shipping 40,000 Model S electric cars in 2014 and if the 85 kWh battery, which uses 7,104 of these cells, had proved as popular overseas as it was in the United States, a 2014 study projected that the Model S alone would use almost 40 percent of estimated global cylindrical battery production during 2014. , production was gradually shifting to higher-capacity 3,000+ mAh cells. Annual flat polymer cell demand was expected to exceed 700 million in 2013.
Prices of lithium-ion batteries have fallen over time. Overall, between 1991 and 2018, prices for all types of lithium-ion cells (in dollars per kWh) fell approximately 97%. Over the same time period, energy density more than tripled. Efforts to increase energy density contributed significantly to cost reduction.
In 2015, cost estimates ranged from $300–500/kWh. In 2016 GM revealed they would be paying for the batteries in the Chevy Bolt EV. In 2017, the average residential energy storage systems installation cost was expected to drop from $1600 /kWh in 2015 to $250 /kWh by 2040 and to see the price with 70% reduction by 2030. In 2019, some electric vehicle battery pack costs were estimated at $150–200, and VW noted it was paying for its next generation of electric vehicles.
Batteries are used for grid energy storage and ancillary services. For a Li-ion storage coupled with photovoltaics and an anaerobic digestion biogas power plant, Li-ion will generate a higher profit if it is cycled more frequently (hence a higher lifetime electricity output) although the lifetime is reduced due to degradation.
Several types of lithium nickel cobalt manganese oxide (NCM) and lithium nickel cobalt aluminium oxide (NCA) cathode powders with a layered structure are commercially available. Their chemical compositions are specified by the molar ratio of component metals. NCM 111 (or NCM 333) have equimolar parts of nickel, cobalt and manganese. Notably, in NCM cathodes, manganese is not electroactive and remains in the oxidation state +4 during battery's charge-discharge cycling. Cobalt is cycled between the oxidation states +3 and +4, and nickel - between +2 and +4. Due to the higher price of cobalt and due to the higher number of cyclable electrons per nickel atom, high-nickel (also known as "nickel-rich") materials (with Ni atomic percentage > 50%) gain considerable attention from both battery researchers and battery manufacturers. However, high-Ni cathodes are prone to O2 evolution and Li+/Ni4+ cation mixing upon overcharging.
, NMC 532 and NMC 622 were the preferred low-cobalt types for electric vehicles, with NMC 811 and even lower cobalt ratios seeing increasing use, mitigating cobalt dependency. However, cobalt for electric vehicles increased 81% from the first half of 2018 to 7,200 tonnes in the first half of 2019, for a battery capacity of 46.3 GWh.
In 2010, global lithium-ion battery production capacity was 20 gigawatt-hours.
By 2016, it was 28 GWh, with 16.4 GWh in China. Production in 2021 is estimated by various sources to be between 200 and 600 GWh, and predictions for 2023 range from 400 to 1,100 GWh.
An antitrust-violating price-fixing cartel among nine corporate families, including LG Chem, GS Yuasa, Hitachi Maxell, NEC, Panasonic/Sanyo, Samsung, Sony, and Toshiba was found to be rigging battery prices and restricting output between 2000 and 2011.
References
Lithium-ion battery
Lithium-ion battery | History of the lithium-ion battery | [
"Technology",
"Engineering"
] | 4,642 | [
"Science and technology studies",
"History of technology",
"Electrical engineering",
"History of science and technology",
"History of electrical engineering"
] |
69,154,444 | https://en.wikipedia.org/wiki/Brellochs%20reaction | In organoboron chemistry, the Brellochs reaction provides a way to generate the monocarboranes. The use of acetylenes to insert two carbons into boron hydrides is well established. The Brellochs method uses formaldehyde to insert single carbon atoms into boron hydrides.
Illustrative is the synthesis of CB9H14− from commercially available decaborane.
B10H14 + CH2O + 2 OH− + H2O → CB9H14− + B(OH)4− + H2
Oxidation of the arachno anion gives nido-6-CB9H12−. Base degradation of the latter gives arachno-4-CB8H14.
References
Organoboron compounds
Cluster chemistry | Brellochs reaction | [
"Chemistry"
] | 167 | [
"Cluster chemistry",
"Organometallic chemistry"
] |
69,154,598 | https://en.wikipedia.org/wiki/SN%202020fqv | SN 2020fqv was a type II supernova which occurred in March 2020 in the spiral galaxy NGC 4568, approximately 60 million light years from Earth. The explosion was detected by both the Zwicky Transient Facility and the Transiting Exoplanet Survey Satellite. Observations were obtained by the Hubble Space Telescope both years before and just 26 hours after it exploded, as well as many other instruments, providing the first holistic view of such an event.
The progenitor star is modelled to be a red supergiant with a radius of and a mass of , fairly typical of type II supernova progenitors.
References
Supernova remnants
Supernovae
Astronomical objects discovered in 2020
Virgo (constellation) | SN 2020fqv | [
"Chemistry",
"Astronomy"
] | 148 | [
"Supernovae",
"Astronomical events",
"Virgo (constellation)",
"Constellations",
"Explosions"
] |
69,154,846 | https://en.wikipedia.org/wiki/Apple%20Polishing%20Cloth | The Polishing Cloth is a small piece of off-white microfiber cloth sold by Apple Inc. since October 2021 as a screen cleaning aid for its laptops and mobile devices. It is also intended as a replacement for the cloth that comes with Apple's monitors such as the Pro Display XDR, and is designed for cleaning the 'nano-texture glass' version of the monitor with.
The cloth gained media attention due to its high $19 retail price. The New York Times described this pricing as "bold even by Apple’s standards, a company whose legions of loyal customers are conditioned to stomach steep prices." Nonetheless, it was Apple's most back-ordered item in October 2021, with delivery times of several months. The expensive cloth and its popularity were soon the subject of numerous jokes in the media and on social media, which in turn provided grounds for criticism of the media for providing Apple's extravagances with free advertising.
The tech website iFixit 'disassembled' the cloth as part of a tongue-in-cheek product teardown, describing it as being composed of two layers and having "a distinct synthetic leather feel (...) with a hint of fuzziness, similar to Alcantara." The cloth also has the Apple logo embossed in the bottom right corner.
See also
iPod Socks
References
Apple Inc. products
Cleaning products
Products introduced in 2021 | Apple Polishing Cloth | [
"Chemistry"
] | 288 | [
"Cleaning products",
"Products of chemical industry"
] |
69,155,647 | https://en.wikipedia.org/wiki/Antimony%28III%29%20oxide%20hydroxide%20nitrate | Antimony(III) oxide hydroxide nitrate is an inorganic compound with the chemical formula Sb4O4(OH)2(NO3)2. It is one of the very few nitrates of antimony. No evidence for a simple trinitrate has been reported. According to X-ray crystallography, its structure consists of cationic layers of antimony oxide/hydroxide with intercalated nitrate anions. This compound is produced by the reaction of antimony(III) oxide and nitric acid at 110 °C.
References
Antimony(III) compounds
Nitrates | Antimony(III) oxide hydroxide nitrate | [
"Chemistry"
] | 122 | [
"Oxidizing agents",
"Nitrates",
"Salts"
] |
69,155,769 | https://en.wikipedia.org/wiki/%28%2B%29-Morphine | (+)-Morphine also known as dextro-morphine is the "unnatural" enantiomer of the opioid drug (−)-morphine. Unlike "natural" levo-morphine, unnatural dextro-morphine is not present in Papaver somniferum and is the product of laboratory synthesis.
In contrast to natural morphine, the unnatural enantiomer has no affinity or efficacy for the mu opioid receptor and therefore has no analgesic effects. To the contrary, in rats, (+)-morphine acts as an antianalgesic and is approximately 71,000 times more potent as an antianalgesic than (−)-morphine is as an analgesic. (+)-Morphine derives its antianalgesic effects by being a selective-agonist of the Toll-like receptor 4 (TLR4), which due to not binding to opioid receptors allows it to effectively reverse the analgesic properties of (−)-morphine. TLR4 is involved in immune system responses, and activation of TLR4 induces glial activation and release of inflammatory mediators such as TNF-α and Interleukin-1.
See also
(+)-Naloxone
Dextromethorphan
References
Morphine
Cyclohexenols
Ethers
Hydroxyarenes | (+)-Morphine | [
"Chemistry"
] | 290 | [
"Organic compounds",
"Functional groups",
"Ethers"
] |
69,155,929 | https://en.wikipedia.org/wiki/Killers%20of%20the%20Cosmos | Killers of the Cosmos is a documentary science television series hosted by Aidan Gillen. Aired by the Science Channel, it premiered on September 19, 2021.
Format
In a format the Science Channel describes as "space noir," Killers of the Cosmos explores possible lethal threats the cosmos poses to life on Earth through the "investigations" of a private investigator—the "Gumshoe Detective," modeled in the style of a character in a Raymond Chandler novel—portrayed by Aidan Gillen in animated form. In scripted dramatic sequences combining the characteristics of film noir with those of a pulp fiction graphic novel set in the mid-20th century, the Gumshoe Detective hosts each episode. Aided by a mysterious informant portrayed by Sarah Winter, the detective takes on a "case" and hunts down a "killer" by exploring a lethal threat the cosmos poses to humanity. The animated sequences link conventional live-action documentary segments in which experts in astronomy, astrophysics, cosmology, planetary science, biology, and aerospace engineering describe and explain phenomena that could threaten the Earth, how they pose a threat, what would happen on Earth if they actually took place, the likelihood of them occurring, and how to counter them.
Production
Wall to Wall Media produced Killers of the Cosmos. The executive producers for Wall to Wall Media were Tim Lambert and Jeremy Dear and for Discovery, Inc., were Caroline Perez, Abram Sitzer and Wyatt Channell. The series producer was Nigel Paterson. Ben Scott directed the episodes.
Episode list
SOURCES
See also
Alien Planet
Cosmos: A Spacetime Odyssey
Extreme Universe
How the Universe Works
Into the Universe with Stephen Hawking
The Planets and Beyond
Space's Deepest Secrets
Strip the Cosmos
Through the Wormhole
The Universe
References
External links
tvmaze.com Killers of the Cosmos – Episode Guide
Discovery UK Killers of the Cosmos promotional video on YouTube
2021 American television series debuts
2020s American documentary television series
American television series with live action and animation
Documentary television series about astronomy
Science Channel original programming
Television series by Warner Bros. Television Studios | Killers of the Cosmos | [
"Astronomy"
] | 405 | [
"Documentary television series about astronomy",
"Works about astronomy"
] |
69,156,929 | https://en.wikipedia.org/wiki/MacroDroid | MacroDroid is an automation app for Android. Jamie Higgins is the developer of MacroDroid, and the app supports Tasker plugins. The app has also been described as a simpler version of Tasker.
The app has been in development since at least 2012. In 2014, automation for Wear OS devices was introduced.
Usage
The app works on both rooted devices and ordinary devices, though some functions will only work on a rooted device. It includes many pre-made macros.
See also
Tasker
References
External links
MacroDroid website
Android (operating system) software | MacroDroid | [
"Engineering"
] | 116 | [
"Automation software",
"Automation"
] |
69,157,556 | https://en.wikipedia.org/wiki/Federico%20Grisogono | Federico Grisogono, Federico Crisogono, Latinized as Federicus De Chrysogonis (1472 – 2 February 1538) was a renaissance Dalmatian astrologer, physician, geometer, and humanistic philosopher.
Grisogono was born into aristocracy, the son of Antonio and Catarina Giorgi of Zadar (Zara). Orphaned at the age of five but with a large inheritance, he was raised by an uncle Franjo. He studied in Italy and France, attended classes in philosophy and medicine at the University of Padua where a maternal cousin, Jeronim Civalleli, was rector. In 1499, he served as a condottiero and fought in Lombardy. He returned to his studies and received a medical doctorate around 1506–7. He then taught astrology and mathematics at Padua before returning to Zadar. He examined the patterns of tides and noting that it was due to the sun and the moon came up with an approach to predicting the tides. He published the Speculum astronomicum (1507) as well as a book on humanistic philosophy De modo collegiandi...de humana felicitate (1528).
References
External links
Brief biography
Speculum astronomicum (1507) transcription
De modo collegiandi, pronosticandi, et curandi febres, nec non de humana felicitate ac denique de fluxu maris lucubrationes (1528)
1472 births
1538 deaths
Dalmatian Italians
Astrologers | Federico Grisogono | [
"Astronomy"
] | 326 | [
"People associated with astronomy",
"Astrologers"
] |
69,158,898 | https://en.wikipedia.org/wiki/Sulli%20Deals | "Sulli Deals" was an open-source app which contained photographs and personal information of some 100 Muslim women online. An FIR was filed by the Delhi Police with National Commission for Women India taking suo moto cognisance of the matter on 8 July 2021. The creator of the app was a BCA Student from Indore, Madhya Pradesh. On 9 January 2022, Thakur, who created the app to "defame" Muslim women, was arrested by the Delhi Police. Thakur was granted bail on 29 March by the court.
Incident
On 4 July 2021, several pictures of Muslim women were posted on Twitter, where each was described as a "deal of the day". Several accounts spoke against the app, which was hosted on GitHub as an "open-source project." After multiple complaints, GitHub took the app down and suspended the "sullideals" account which hosted the app.
This was not the first time Muslim women were harassed by right-wing social media users. In May 2021, a YouTuber named Liberal Doge "rated out of 10" Pakistani women in his livestream and some group of anonymous accounts harassed Hasiba Amin, the National Convenor of Congress IT Cell. According to analysts, the same group of people were behind the Sulli Deals app. However, Liberal Doge denied any connection with the Sulli Deals app.
Reaction
Commentators have described the app as targeted harassment against Muslim women, with NCW taking suo moto cognizance over the matter and Delhi Police Cyber Cell registering an FIR under section 354-A. One of the targeted women, pilot Hina Khan, filed a separate FIR with Delhi Police under section 509 and section 66,67 of the IT Act. Shiv Sena MP Priyanka Chaturvedi wrote to the IT minister demanding strict and urgent action against the creators of the app. In addition, 56 MPs across party lines signed a letter to the home minister Amit Shah seeking redressal.
Congress MP Shashi Tharoor and AIMIM president Asaduddin Owaisi showed solidarity with the targeted women and assured that they would pursue the case to prevent further misuse of social media. More than 800 women-rights activists from all over India released a statement seeking action against the culprits.
Both GitHub and Twitter were criticized for failing to prevent further harassment of Muslim women after the auction fiasco and not taking quick action against the sullideals account. As of November 2021, the identity of the creator of the app was still unknown, with GitHub refusing to share data to Indian authorities through the usual CrPC notice.
On 6 January 2022, the Delhi Police said they were looking for the actual creator of the app through MLAT.
On 11 January 2022, the United Nations Special Rapporteur on Minority Issues, Fernand de Varennes, said, "Minority Muslim women in India are harassed and ‘sold’ in social media apps, #SulliDeals, a form of hate speech, must be condemned and prosecuted as soon as they occur. All Human Rights of minorities need to be fully and equally protected".
Arrest
In January 2022, Delhi police arrested the creator of Sulli Deals, in Indore, Madhya Pradesh.
Aftermath
In 2022, a similar app named Bulli Bai was created to auction Muslim women, in which the same Trad group was involved. Police arrested Neeraj Bishnoi, an engineering student, in the case.
In March 2022, Niraj Bishnoi was granted bail by the court.
Notes
References
2021 in India
July 2021 crimes in Asia
2021 controversies
Sexual harassment in India
Cybercrime in India
Cyberbullying
Defunct websites
2021 in Internet culture
Online sex crimes
Islamophobia in India
Indian websites
Internet properties established in 2021
Internet properties disestablished in 2021
Internet trolling
Online obscenity controversies
Shock sites
Internet forums
Internet-related controversies
Stalking
Delisted applications
Hindutva
Sexism in India | Sulli Deals | [
"Biology"
] | 812 | [
"Behavior",
"Aggression",
"Stalking"
] |
69,159,862 | https://en.wikipedia.org/wiki/German%20Centre%20for%20Rail%20Traffic%20Research | The German Centre for Rail Traffic Research () is an independent, technical-scientific departmental research institution of the Federal Government. It was founded on May 23, 2019, and is located as an independent federal institute at the Eisenbahn-Bundesamt. Its mission is to strengthen rail transport in Germany through application and solution-oriented research.
The budget for 2019 was 5 million euros and was expected to increase to 20 million euros in 2020. 2020 staff should be built up first and the research content (along the federal research program) should be specified later.
Tasks
The coalition agreement for the 19th Election Period foresees a German Centre for Rail Transport Research (DZSF). This center should document research findings, manage and coordinate research projects, and also carry out research itself. This is intended to achieve a more effective use of resources and a lasting strengthening of railway traffic as a mode of transport.
The DZSF deals with the central issues of the railway sector as defined in the Federal Rail Research Program and provides solutions for them. Research fields are
Economic efficiency
Environment and sustainable Mobility, and
Safety.
The cross-cutting topics of digitalization, automation, migration, and legal issues are assigned to these three topic areas. These cross-cutting topics complement the integrative approach of the federal research program.
References
External links
Internetseite Deutsches Zentrum für Schienenverkehrsforschung
Bundesforschungsprogramm Schiene vom Juli 2021
2019 establishments in Germany
Research institutes in Germany
Research institutes established in 2019
German federal agencies
Government agencies established in 2019
Rail transport in Germany
Engineering research institutes
Transport education | German Centre for Rail Traffic Research | [
"Physics",
"Engineering"
] | 333 | [
"Physical systems",
"Transport",
"Engineering research institutes",
"Transport education"
] |
69,159,943 | https://en.wikipedia.org/wiki/Organic%20azide | An organic azide is an organic compound that contains an azide (–) functional group. Because of the hazards associated with their use, few azides are used commercially although they exhibit interesting reactivity for researchers. Low molecular weight azides are considered especially hazardous and are avoided. In the research laboratory, azides are precursors to amines. They are also popular for their participation in the "click reaction" between an azide and an alkyne and in Staudinger ligation. These two reactions are generally quite reliable, lending themselves to combinatorial chemistry.
History
Phenyl azide ("diazoamidobenzol"), was prepared in 1864 by Peter Griess by the reaction of ammonia and phenyldiazonium. In the 1890s, Theodor Curtius, who had discovered hydrazoic acid (), described the rearrangement of acyl azides to isocyanates subsequently named the Curtius rearrangement. Rolf Huisgen described the eponymous 1,3-dipolar cycloaddition.
The interest in azides among organic chemists has been relatively modest due to the reported instability of these compounds. The situation has changed dramatically with the discovery by Sharpless et al. of Cu-catalysed (3+2)-cycloadditions between organic azides and terminal alkynes. The azido- and the alkyne groups are "bioorthogonal", which means they do not interact with living systems, and at the same time they undergo an impressively fast and selective coupling. This type of formal 1,3-dipolar cycloaddition became the most famous example of so-called "click chemistry" (perhaps, the only one known to a non-specialist), and the field of organic azides exploded.
Preparation
Myriad methods exist, most often using preformed azide-containing reagent.
Alkyl azides
By halide displacement
As a pseudohalide, azide generally displaces many leaving group, e.g. , , , sulfonate, and others to give the azido compound. The azide source is most often sodium azide (), although lithium azide () has been demonstrated.
From alcohols
Aliphatic alcohols give azides via a variant of the Mitsunobu reaction, with the use of hydrazoic acid. Hydrazines may also form azides by reaction with sodium nitrite: Alcohols can be converted into azides in one step using 2-azido-1,3-dimethylimidazolinium hexafluorophosphate (ADMP) or under Mitsunobu conditions with diphenylphosphoryl azide (DPPA).
From epoxides and aziridines
Trimethylsilyl azide , and tributyltin azide , have all been used, including enantioselective modifications of the reaction are also known. Aminoazides are accessible by the epoxide and aziridine ring cleavage, respectively.
From amines
The azo-transfer compounds, trifluoromethanesulfonyl azide and imidazole-1-sulfonyl azide react with amines to give the corresponding azides. Diazo transfer onto amines using trifluoromethanesulfonyl azide () and Tosyl azide () has been reported.
Hydroazidation
Hydroazidation of alkenes has been demonstrated
Aryl azides
Aryl azides may be prepared by displacement of the appropriate diazonium salt with sodium azide or trimethylsilyl azide. Nucleophilic aromatic substitution is also possible, even with chlorides. Anilines and aromatic hydrazines undergo diazotization, as do alkyl amines and hydrazines.
Acyl azides
Alkyl or aryl acyl chlorides react with sodium azide in aqueous solution to give acyl azides, which give isocyanates in the Curtius rearrangement.
Dutt–Wormall reaction
A classic method for the synthesis of azides is the Dutt–Wormall reaction in which a diazonium salt reacts with a sulfonamide first to a diazoaminosulfinate and then on hydrolysis the azide and a sulfinic acid.
Reactions
Organic azides engage in useful organic reactions. The terminal nitrogen is mildly nucleophilic. Generally, nucleophiles attack the azide at the terminal nitrogen Nγ, while electrophiles react at the internal atom Nα. Azides easily extrude diatomic nitrogen, a tendency that is exploited in many reactions such as the Staudinger ligation or the Curtius rearrangement.
Azides may be reduced to amines by hydrogenolysis or with a phosphine (e.g., triphenylphosphine) in the Staudinger reaction. This reaction allows azides to serve as protected -NH2 synthons, as illustrated by the synthesis of 1,1,1-tris(aminomethyl)ethane:
In the azide alkyne Huisgen cycloaddition, organic azides react as 1,3-dipoles, reacting with alkynes to give substituted 1,2,3-triazoles.
Some azide reactions are shown in the following scheme. Probably the most famous is the reaction with phosphines, which leads to iminophosphoranes 22; these can be hydrolysed into primary amines 23 (the Staudinger reaction), react with carbonyl compounds to give imines 24 (the aza-Wittig reaction), or undergo other transformations. Thermal decomposition of azides gives nitrenes, which participate in a variety of reactions; vinyl azides 19 decompose into 2H-azirines 20. Alkyl azides with low nitrogen-content ((nC + nO) / nN ≥ 3) are relatively stable and decompose only above ca. 175 °C.
Direct photochemical decomposition of alkyl azides leads almost exclusively to imines (e.g. 25 and 26). It is proposed that the azide group is promoted to the singlet excited state and then undergoes concerted rearrangement without the intermediacy of nitrenes. The presence of triplet sensitisers, however, may change the reaction mechanism and result in the formation of triplet nitrenes. The latter were observed directly by ESR spectroscopy at −269 °C as well as inferred in some photolyses. Triplet methyl nitrene is 31 kJ/mol more stable than its singlet form, and thus is most likely the ground state.
The (3+2)-cycloaddition of azides to double or triple bonds is one of the most utilised cycloadditions in organic chemistry and affords triazolines (e.g. 17) or triazoles, respectively. The uncatalysed reaction is a concerted pericyclic process, in which the configuration of the alkene component is transferred to the triazoline product. The Woodward–Hoffmann denomination is [π4s+π2s] and the reaction is symmetry-allowed. According to Sustmann, this is a Type II cycloaddition, which means the two HOMOs and the two LUMOs have comparable energies, and thus both electron-withdrawing and electron-donating substituents may lead to an increase in the reaction rate. The reaction is generally free from significant solvent effects because both the reactants and the transition state (TS) are non-polar.
Another azide regular is tosyl azide here in reaction with norbornadiene in a nitrogen insertion reaction:
Applications
Some azides are valuable as bioorthogonal chemical reporters, molecules that can be "clicked" to see the metabolic path it has taken inside a living system.
The antiviral drug zidovudine (AZT) contains an azido group.
Safety
Some organic azides are classified as highly explosive and toxic.
References
Additional sources
Wolff, H. Org. React. 1946, 3, 337–349.
External links
Synthesis of organic azides, recent methods
Synthesizing, Purifying, and Handling Organic Azides
Functional groups
Leaving groups | Organic azide | [
"Chemistry"
] | 1,749 | [
"Functional groups",
"Leaving groups"
] |
62,520,275 | https://en.wikipedia.org/wiki/IBM%20drum%20storage | In addition to the drums used as main memory by IBM, e.g., IBM 305, IBM 650, IBM offered drum devices as secondary storage for the 700/7000 series and System/360 series of computers.
IBM 731
The IBM 731 is a discontinued storage unit used on the IBM 701. It has a storage capacity of 2,048 36-bit words (9,216 8-bit bytes).
IBM 732
The IBM 732 is a discontinued storage unit used on the IBM 702. It has a storage capacity of 60,000 6-bit characters (45,000 8-bit bytes).
IBM 733
The IBM 733 is a discontinued storage unit used on the IBM 704 and IBM 709. It has a storage capacity of 8192 36-bit words (36,864 8-bit bytes).
IBM 734
The IBM 734 is a discontinued storage unit used on the IBM 705 It has a storage capacity of 60,000 6-bit characters (45,000 8-bit bytes).
IBM 7320
The IBM 7320 is a discontinued storage unit manufactured by IBM announced on December 10, 1962 for the IBM 7090 and 7094 computer systems, was retained for the earliest System/360 systems as a count key data device, and was discontinued in 1965. The 7320 is a vertically mounted head-per-track device with 449 tracks, 400 data tracks, 40 alternate tracks, and 9 clock/format tracks. The rotational speed is 3,490 rpm, so the average rotational delay is 8.6 milliseconds.
Attachment to a 709x system is through an IBM 7909 Data Channel and an IBM 7631 File Control unit, which can attach up to five random-access storage units, a mix of 7320 and 1301 DASD. One or two 7631 controllers can attach to a computer system, but the system can still attach only a total of five DASD. When used with a 709x, a track holds 2,796 6-bit characters, and a 7320 unit holds 1,118,400 characters. Data transfer rate is 202,800 characters per second.
The 7320 attaches to a System/360 through a channel and an 2841 Storage Control unit. Each 2841 can attach up to eight 7320 devices. When used with System/360, a track holds 2,081 8-bit bytes, and a 7320 unit holds 878,000 bytes. Data transfer rate is 135,000 bytes per second.
The 7320 was superseded by the IBM 2301 in mid-1966.
IBM 2301
The IBM 2301 is a magnetic drum storage device introduced in the late 1960s to "provide large capacity, direct access storage for IBM System/360 Models 65, 67, 75, or 85." The vertically mounted drum rotates at around 3,500 revolutions per minute, and has a head-per-track access mechanism and a capacity of 4 MB. The 2301 has 800 physical tracks; four physical tracks make up one logical track which is read or written as a unit. The 200 logical tracks have 20,483 bytes each. The average access time is 8.6 ms, and the data transfer rate is 1,200,000 bytes per second. The 2301 attaches to a System/360 via a selector channel and an IBM 2820 Storage Control Unit, which can control up to four 2301 units.
IBM 2303
The IBM 2303 is a magnetic drum storage device with the same physical specifications as the IBM 2301. The difference is that the 2303 reads and writes one physical track at a time, rather than the four in the 2301, reducing the data transfer rate to 312,500 bytes per second. The 2303 attaches to System/360 through a channel and an IBM 2841 Storage Control Unit, which can attach up to two 2303 units.
See also
Drum memory: Drums used as main memory
References
History of computing hardware
7320
Computer storage devices | IBM drum storage | [
"Technology"
] | 824 | [
"Computer storage devices",
"Recording devices",
"History of computing hardware",
"History of computing"
] |
62,520,335 | https://en.wikipedia.org/wiki/Fort%20Souville | Fort Souville, briefly called Fort Lemoine, was one of the forts of the Verdun Fortification District, situated in the commune of Fleury-devant-Douaumont. Constructed between 1876 and 1879 at an altitude of 396m, it is a first generation fort. It served as a key battlefield in the 1916 Battle of Verdun during World War I. The fort was armed on its ramparts with 9 cannons and 5 mortars, with 8 pieces of artillery used as flanking fire. A Bussiere turret in attached battery was also present.
Location
The fort is part of the interior belt of forts, one of two belts securing Verdun. Fort Souville was part of the first sector (Northeast of the city), serving as the first sector commander's headquarters, connected to central command via telephone.
Fort Souville is located south of Fort Douaumont and southwest of Fort Vaux.
History
The fort was one of the first forts of the Séré de Rivières system, being constructed of masonry and limestone rubble covered with soil. Built 1875–1879, the fort was modified from 1888–1890, excavating underground shelters and reinforcing the powder magazine with concrete.
The planned garrison was 326 men and 32 artillery pieces. The fort's name originates not from a nearby settlement, but from the birthplace of the designer, Gustave de la Taille.
A turret for two 155mm Bussière cannons was installed from 1890–1891, 120m to the west of the fort.
By the Decree of 21 January 1887, the Minister of War Georges Boulanger renamed all forts, batteries, and barracks to those of prior military leaders. Fort Souville was thus rechristened Fort Lemoine, in reference to General Louis Lemoine. The new name was engraved on the pediment of the entrance. On 13 October 1887, Boulanger's successor, Théophile Ferron, abrogated the decree. The fort returned to its prior name while retaining the inscription at the entrance.
July 1916 Combat
On 11 July 1916, the Bavarian Guard infantry launched an assault on the village of Fleury and attempted to seize Fort Souville.
The Fleury sector was held by the French 128th Division under the command of general Riberpray. the 167th and 168th Infantry Regiment of the 255th Brigade under Colonel Coquelin de Lisle held the front line. The 167th held the foremost position, with the 168th providing support from behind.
On 9 July, the 167th Regiment was shelled by German Artillery using both explosive and gas shells.
During the night of 10 July, a captured German officer was interrogated by the 167th Regiment, revealing the planned assault for the next day.
At 5 am on 11 July, a violent bombardment began on the French lines prior to the assault by German infantry. At 5:42, the Bavarian Guards launched their assault, with flamethrowers in tow. They penetrated the French lines before the French had time to react, with ensuing hand-to-hand combat with both grenade and bayonet.
The German gas and shells interrupted all heliograph communications with Fort Souville.
At 6 o'clock, Colonel Coquelin de Lisle sent a homing pigeon with the following message: "The 255th Brigade's situation in front of Fleury is grave, with gas bombardments and the enemy's attacks, which were delayed, and morale is high but the men are exhausted. I need artillery support with 100 red fuses and 100 white fuses. The main attack appears to be between the station and the village of Fleury.
By 6:50, the Germans were approaching brigade headquarters. The order to burn confidential documents was given, with Colonel Coquelin de Lisle fighting with his rifle side by side with his men.
The 140th East Prussian Infantry Regiment aimed to seize Fort Souville, but failed to break through French lines. Meanwhile, the Bavarian attack progressed from south of Fleury to near Fort Souville. However, heavy French artillery fire inflicted severe casualties, causing the attack to stall.
However, a shell destroyed the Ménétrier battalion's machine guns, situated between the Ménétrier and Gérard battalions. German forces penetrated this gap and advanced closer to brigade headquarters, with Colonel Coquelin de Lisle killed in combat.
In the evening, the 169th and 100th Infantry Regiments moved towards "the ravine of Our Lady", which was called "the ravine of Death" by the men. The 100th regiment advanced at the head of the line, with its 2nd and 3rd battalions led the march while the 1st battalion stayed in reserve. They drove back elements of the Bavarian Guards who had crossed the railway, taking 80 prisoners. During the night, a severe German bombardment on "the ravine of Death" inflicted severe casualties on the 1st battalion, which had advanced in support of the 2nd. The majority of its soldiers were killed, as well as their leader, Commander Forlet.
On 12 July a force of around 30 German soldiers reached the fort itself but were repelled by a counterattacked led by French Lieutenant Kléber Dupuy.
Order of Battle
German:
Bavarian Guard Infantry Regiment
3 battalions
140th East Prussian Infantry Regiment.
3 battalions
French:
255th Infantry Brigade (and munitions depot)
167th Infantry Regiment.
Gérard Battalion(1st Battalion)
Lebrun Battalion(2nd Battalion)
Ménétrier Battalion(3rd Battalion)
100th Infantry Regiment.
2 battalions
Wartime Publicity
The war artist François Flameng illustrated the events of Fort Souville in numerous sketches and drawings in the magazine L'Illustration.
Current State
After several years, Fort Souville was abandoned, having become obsolete by artillery and Verdun's location. The fort has since deteriorated, but visitors may still visit and take photos while exploring the site.
References
External links
Séré de Rivières system | Fort Souville | [
"Engineering"
] | 1,214 | [
"Séré de Rivières system",
"Fortification lines"
] |
62,520,510 | https://en.wikipedia.org/wiki/Gigot%20bitume | A (asphalt leg of lamb) is a leg of lamb prepared by wrapping the meat in kraft paper and placing it in a bath of hot asphalt. This preparation method is traditionally used in France to celebrate the completion of the structural portion of construction projects or public works.
A recipe for the dish, , appears in the 1900 cookbook ("True Practical Cuisine: Soups, Fish, Beef, Veal, Lamb, Mutton, Pork, Poultry, Game")
Usage of this cooking method by asphalt workers, in particular, has existed since the end of the 19th century.
In Val-de-Travers in western Switzerland, a similar tradition exists where a ham is cooked in asphalt (Jambon cuit dans l’asphalte).
References
French meat dishes
Lamb dishes
Asphalt
Ceremonies in France
Closing ceremonies
19th-century establishments in France
Ceremonial food and drink
Construction in Europe | Gigot bitume | [
"Physics",
"Chemistry"
] | 176 | [
"Amorphous solids",
"Asphalt",
"Unsolved problems in physics",
"Chemical mixtures"
] |
62,520,795 | https://en.wikipedia.org/wiki/Jason%20Simon%20%28artist%29 | Jason Simon (born 1961) is an American artist.
Early life
Jason Simon was born in 1961 in Boston, Massachusetts, to parents who had emigrated from South Africa via London. His father, Morris Simon, was a radiologist and inventor, and his mother, Josephine Simon, worked in community theater and arts education, eventually creating the first Masters in Women's Studies program at the Goddard Cambridge Program for Social Change. Simon is the nephew of South African writer, playwright, and director Barney Simon. He pursued undergraduate studies in literature and film at Sarah Lawrence College and Columbia University's School of General Studies, from 1979 to 1984. He is a 1984–85 alumnus of the Whitney Museum of American Art Independent Study Program, and earned a Masters of Fine Arts from the University of California, San Diego, in 1988.
Early career and education
Simon left his undergraduate studies in 1981 to work in Cambridge, MA, for Stuart Cody, an audio engineer associated with the ethnographic film and American Direct Cinema community there. Returning to school a year later, he finished his studies at Columbia and the Whitney Museum Independent Study Program while working as a sound recordist in independent film production and advertising. This period resulted in his film and video projects Production Notes: Fast Food for Thought (1987), and Artful History: A Restoration Comedy (1987). He left New York City to study at UC San Diego from 1986–1988.
Exhibitions and curating
Production Notes: Fast Food for Thought was selected for the 1989 Whitney Biennial, at the Whitney Museum of American Art, New York. The work is a roughly 30-minute tape addressing the first-hand intentions and semiotics of high-budget television commercials that Simon had worked on. That same year, Simon premiered at the Collective for Living Cinema in New York City, together with the artist Mark Dion, their film Artful History: A Restoration Comedy, which explores the business of fine art restoration—its mercantilism and the narratives of the skilled artisans entwined in it.
Later in 1989, Simon joined the staff of the newly opened Wexner Center for the Arts, at Ohio State University, Columbus, Ohio, working alongside curator and art historian Bill Horrigan. At the museum, he served as an Assistant Curator of film and video through 1991, while also establishing the museum's unique technological laboratory for artists to produce professional films, which was originally called the Art & Tech Residency.
Following his role at the Wexner Center for the Arts, Simon began to organize video programming across institutions in Europe and New York. Programs such as "Downsizing the Image Factory" were screened at venues including Kunstverein München (1994), L'Unité d'Habitation, Firminy, France (1993), and Philadelphia Museum of Art (1995). In New York, Simon organized video programs including "Man Trouble," at Exit Art (1994), and "The Talking Cure," at Artists Space (1992), both New York. Much of these events consisted of video works by artists practicing at the time and capturing contemporary concerns of media, spectatorship, and activism.
By the mid-90s, Simon was beginning to exhibit his own multimedia work in one-person exhibitions. In 1994, he presented "The Mayfair Show," at the Mayfair Club and at American Fine Arts, Co., both in New York. The exhibition focused on connections between artmaking and gambling through the lens of psychoanalysis, and would travel years later to Yale Union, Portland, OR, in 2016. As part of his representation with the Pat Hearn Gallery, Simon presented three solo exhibitions, one in 1994 titled "Album," an arrangement of large-scale polaroid photographs. His 1996 exhibition at the gallery, entitled "Spirits," included a selection of hand-toned silver gelatin prints that depicted various sinewy, curvilinear representations of cigarette smoke. In 1998, he presented his exhibition "Public Address: Collapsed" at Pat Hearn Gallery, a tableau with stadium-scale speaker horns resting on the gallery floor. Writing in the pages of Artforum, art historian George Baker likened the exhibition to "a scene of catastrophe," that "opened up a surprising number of reflections on contemporary sculptural production."
In the spring of 2005, Simon, along with several other collaborators, began operating Orchard, a cooperatively run gallery in New York City's Lower East Side. Orchard's primary format was to organize exhibitions of various artists by thematically connected groups, while also establishing connections between different artistic generations and reintroducing lesser-known historical artists or art projects. The project space was intended to last for three years and concluded in May 2008. In April 2006, Jason Simon exhibited his film Vera at Orchard, which he shot in 2003. The 25-minute video work is an interview with a woman named Vera that discusses her addiction to purchasing designer clothes and accessories, and the psychology of consumerism, debt and desire.
From 2003 to 2012, with the artist Moyra Davey, Simon organized the "One-Minute Film Festival," an annual summer gathering in a barn in upstate New York. Each year, dozens of artists would present new films lasting sixty seconds in length. By the time of the project's conclusion, over 350 filmmakers had participated to show over 700 films. The project would spawn exhibitions and festivals celebrating the screened films, presented by institutions including the Art Institute of Chicago in 2010, and MASS MoCA in 2013.
In the 2010s, Jason Simon's art was regularly exhibited in New York City with his representation at the gallery Callicoon Fine Arts. In 2012, he presented the exhibition Festschrift for an Archive, which focused on the now-defunct MoMA Film Still Archive headed by Mary Corliss. In a review published by The New Yorker, critic Nana Asfour categorized the exhibition as part the genre known as "institutional critique," a "mode of probing the workings and assumed functions of art institutions." Simon continued to exhibit at Callicoon Fine Arts until the gallery's closing in 2021, with exhibitions in 2013, 2015, and 2018. His 2015 presentation Request Lines are Open, focused on the weekly audience of DJ Liberty Green's radio show Soul Spectrum, on WJFF radio, a non-profit station with a listening area that includes the large state and federal prison population of upstate New York. In 2019, Simon exhibited at the New York City gallery King’s Leap. His show, The Red Books, united all 15 volumes of the American Film Institute's Catalog of Motion Pictures.
Alongside his artistic practice, Simon has maintained a connection to teaching and pedagogy. Apart from his foundational efforts for the Wexner Center's Art and Technology Lab, Simon also participated in the formation of the College of Staten Island's Department of Media Culture in 2002, having worked in the university's Performing and Creative Arts department for three years prior. He continued teaching at the institution's Media Culture department until 2023, and has also taught courses at locales including Sarah Lawrence College, William Paterson University, Royal Danish Academy of Fine Arts, and School of the Art Institute of Chicago.
References
1961 births
Living people
21st-century American artists
Artists from Boston
College of Staten Island faculty
Columbia University School of General Studies alumni
University of California, San Diego alumni
Multimedia artists
American film producers | Jason Simon (artist) | [
"Technology"
] | 1,498 | [
"Multimedia",
"Multimedia artists"
] |
62,521,490 | https://en.wikipedia.org/wiki/The%20Storm%20Book | The Storm Book is a 1952 picture book written by Charlotte Zolotow and illustrated by Margaret Bloy Graham. The book tells the story of a summer storm from the perspective of a young boy. The book was a recipient of a 1953 Caldecott Honor for its illustrations.
References
1952 children's books
American picture books
Caldecott Honor–winning works
Works about weather | The Storm Book | [
"Physics"
] | 77 | [
"Weather",
"Physical phenomena",
"Works about weather"
] |
62,522,558 | https://en.wikipedia.org/wiki/Data-centric%20computing | Data-centric computing is an emerging concept that has relevance in information architecture and data center design. It describes an information system where data is stored independently of the applications, which can be upgraded without costly and complicated data migration. This is a radical shift in information systems that will be needed to address organizational needs for storing, retrieving, moving and processing exponentially growing data sets.
Background
Traditional information system architectures are based on an application-centric mindset. Traditionally, applications were installed, kept relatively static, updated infrequently, and utilized a fixed set of compute, storage, and networking elements to cope with a relatively small set of structured data.
This approach functioned well for decades, but over the past decade, data growth, particularly unstructured data growth, put new pressures on organizations, information architectures and data center infrastructure. 90% of new data is unstructured and, according to a 2018 report, 59% of organizations manage over 10 billion files and objects spread over large numbers of servers and storage nodes. Organizations are struggling to cope with exponential data growth while seeking better approaches to extracting insights from that data using services including Big Data analytics and machine learning. However, existing architectures aren't built to address service requirements at petabyte scale and beyond without significant performance limits.
Traditional architectures fail to fully store, retrieve, move and utilize that data because due to limitations of hardware infrastructure as well as application-centric systems design, development, and management.
Data-centric workloads
There are two problems data-centric computing aims to address.
Organizations need to utilize all available data but traditional applications aren't sufficiently agile or flexible. New shifts toward constant service innovation, supported by emerging approaches to service delivery (including microservices and containers) open new possibilities that step away from traditional application-centric mindsets.
Existing limits of data center hardware also restricts complete movement, management and utilization of unstructured data sets. Conventional CPUs are impeding performance because they do not include specialized capabilities needed for storage, networking, and analysis. Slow storage, including hard drives and SAS/SATA solid state drives over the network can reduce performance and limit data accessibility. New hardware capabilities are needed.
Data-centric computing
Data-centric computing is an approach that merges innovative hardware and software to treat data, not applications, as the permanent source of value. Data-centric computing aims to rethink both hardware and software to extract as much value as possible from existing and new data sources. It increases agility by prioritizing data transfer and data computation over static application performance and resilience.
Data-centric hardware and software
To meet the goals of data-centric computing, data center hardware infrastructure will evolve to address massive scale, rapid growth, the need for very high performance data movement, and extensive calculation requirements.
Distributed hardware infrastructures become the norm, with data and services spread across many compute and storage nodes, both in public clouds and on-premise.
Due to the flattening of Moore's law, new processors are emerging to boost performance, reducing CPU loads by handling intensive tasks including data movement, data protection, and data security.
New technologies like NVMe drives and networking like NVMeoF will become standard components of data-centric computing architectures.
As far as software goes, data-centric computing accelerates the disappearance of traditional static applications. Applications become short-lived, constantly added, updated, or removed as algorithms come and go. Software is redesigned to conduct analysis on all available data instead of subsets. Microservices visit data, conduct calculations and express the results of their process at speeds beyond conventional approaches.
References
Data centers
Data management | Data-centric computing | [
"Technology"
] | 761 | [
"Data management",
"Data centers",
"Data",
"Computers"
] |
62,525,480 | https://en.wikipedia.org/wiki/ENUBET | The Enhanced NeUtrino BEams from kaon Tagging or ENUBET is an ERC funded project that aims at producing an artificial neutrino beam in which the flavor, flux and energy of the produced neutrinos are known with unprecedented precision.
Interest in these types of high precision neutrino beams has grown significantly in the last ten years, especially after the start of the construction of the DUNE and Hyper-Kamiokande detectors. DUNE and Hyper-Kamiokande are aimed at discovering CP violation in neutrinos observing a small difference between the probability of a muon-neutrino to oscillate into an electron-neutrino and the probability of a muon-antineutrino to oscillate into an electron-antineutrino. This effect points toward a difference in the behavior of matter and antimatter. In quantum field theory, this effect is described by a violation of the CP symmetry in particle physics.
The experiments that will measure CP violation need a very precise knowledge of the neutrino cross-sections, i.e. the probability for a neutrino to interact in the detector. This probability is measured counting the number of interacting neutrinos divided by the flux of incoming neutrinos. Current neutrino cross-section experiments are limited by large uncertainties in the neutrino flux. A new generation of cross-section experiment is therefore needed to overcome these limitations with new techniques or high precision beams, as ENUBET.
In ENUBET, neutrinos are produced by focusing mesons in a narrow band beam towards an instrumented decay tunnel, where charged leptons produced in association with neutrinos by mesons' decay can be monitored at the single particle level. Beams like ENUBET are called monitored neutrino beams.
Mesons (essentially pions and kaons) are produced in the interactions of accelerated protons with a Beryllium or Graphite target. The proposed facility is being studied taking into account the energies of currently available proton drivers: 400 GeV (CERN SPS), 120 GeV (FNAL Main Injector), 30 GeV (J-PARC Main Ring).
Kaons and pions are momentum and charge selected in a short transfer line by means of dipole and quadrupole magnets and are focused in a collimated beam into an instrumented decay tube. Large angle muons and positrons from kaon decays (, , ) are measured by detectors on the tunnel walls, while muons from pion decays () are monitored after the hadron dump at the end of the tunnel. The decay region is kept short (40 m) in order to reduce the neutrino contamination from muon decays ().
In this way, the neutrino flux is assessed in a direct way with a precision of 1%, without relying on complex simulations of the transfer line and on hadro-production data extrapolation that currently limits the knowledge of the flux to 5-10%. The ENUBET facility can be used to perform precision studies of the neutrino cross section and of sterile neutrinos or Non-Standard Interaction models. This method can also be extended to detect other leptons in order to have a complete monitored neutrino beam.
The ENUBET project started in 2016. As of 2024, it involves 17 European institutions in 5 European countries and brings together about 80 scientists.
ENUBET studies all technical and physics challenges to demonstrate the feasibility of a monitored neutrino beam: it has built a full-scale demonstrator of the instrumented decay tunnel (3 m length and partial azimuthal coverage) and assesses costs and physics reach of the proposed facility.
The first end-to-end simulation of the ENUBET monitored neutrino beam was published in 2023.
The ENUBET ERC project was completed in 2022. Since March 2019, ENUBET has been part of the CERN Neutrino Platform (NP06/ENUBET) for the development of a new generation of neutrino detectors and facilities.
References
Neutrinos
Neutrino experiments
Nuclear physics | ENUBET | [
"Physics"
] | 870 | [
"Nuclear physics"
] |
62,525,631 | https://en.wikipedia.org/wiki/Nickel%20bis%28stilbenedithiolate%29 | Nickel bis(stilbenedithiolate) or bis(dithiobenzil)nickel is a coordination complex with the formula Ni(S2C2Ph2)2 (where Ph = phenyl). It exists as a black solid that gives green solutions in toluene due to a strong absorption at 855 nm. The complex is a prototype of a large family of bis(dithiolene) complexes or the formula Ni(S2C2R2)2 (R = H, alkyl, aryl). These complexes have attracted much attention as dyes. They are of academic interest because the dithiolenes are noninnocent ligands. The lengths of the C-S and C-C bonds in the backbone, respectively 1.71 and 1.39 Å, are intermediate between double and single bonds.
The complex was prepared originally by treating nickel sulfide with diphenylacetylene. High yielding syntheses involve treating nickel salts with sulfided benzoin. The complex reacts with ligands to form monodithiolene complexes of the type Ni(S2C2Ph2)L2.
References
Coordination complexes
Chelating agents | Nickel bis(stilbenedithiolate) | [
"Chemistry"
] | 247 | [
"Chelating agents",
"Coordination chemistry",
"Process chemicals",
"Coordination complexes"
] |
62,526,122 | https://en.wikipedia.org/wiki/The%20Equatorie%20of%20the%20Planetis | The Equatorie of the Planetis is a 14th-century scientific work which describes the construction and use of an equatorium. It was first studied in the early 1950s by Derek J. Price, and was formerly attributed to Geoffrey Chaucer. However, in 2014 it was shown to be written in the hand of the St Albans monk John Westwyk. It is largely written in Middle English, with some additions in Latin. It is accompanied by extensive astronomical tables, with Latin headings and annotations.
Manuscript
Peterhouse MS 75 was a composite manuscript. In the early 1950s, after Price discovered the Equatorie in it, the manuscript was split into two parts (and both parts rebound): MS 75.I, containing the Equatorie, and MS 75.II, containing works by Nicholas Trivet and Vegetius.
MS 75.I has two parts: fol. 1r-71r contains largely astronomical tables, and some astrological material, in two hands; 71v-78v contains the text of the Equatorie treatise. The parchment is of varying quality, with ten quires of pages measuring 365x260mm (except for the last quires). The ink is brown; there are signs of dampness on the upper edge, especially in the first quire, with some blurring in the fourth quire on the top of the pages. According to Rand Schmidt, the dampness and the wear and tear on some of the quires is evidence that the quires spent some time unbound.
The text contains references to 31 December 1392, and this is used as a baseline date for many of the tables. John North showed that the text was written during the first nine months of 1393. How it came to Peterhouse is not known, but it probably happened during the 15th century; around 1538 it is entered in Peterhouse catalog, as Tab. aequ. planetarum autore Simon Bredon. The Equatorie occupies eight leaves of the manuscript; the phrase Radix chaucer appears on fol. 5v.
The manuscript has been digitised for the Cambridge University Digital Library website, together with a virtual model of the equatorium.
"Radix chaucer"
On f. 5v, in a note on a page full of tables, the manuscript has the number "1392", followed by that number in sexagesimal notation, and the text "deffea xpi & Rxa chaucer". Price, and following him other scholars, expanded this as "differentia Christi et radix Chaucer"—or "the difference (in number of days) between (the year of Christ) and the (year of the) radix of Chaucer"—the radix in question then being the year 1392. F.N. Robinson was not convinced that this (third-person) reference indicated Chaucer's authorship. However, John North argued that the attachment of a name to a relatively "trivial" piece of data made it likely that this was a case of self-citation.
Discovery and authorship
The manuscript was in the library of Peterhouse, Cambridge by 1538, and probably by 1472. It was discovered there by the historian Derek de Solla Price in December 1951. Although the 19th-century manuscript catalogue stated that the manuscript contained "directions for making an astrolabe (?)", Price identified the instrument as a planetary equatorium. He argued that the manuscript was authored by, and written in the hand of, Geoffrey Chaucer. This was a controversial claim, and was treated with some scepticism by Chaucer scholars, though it received influential backing from the historian of astronomy John North. The manuscript was shown to be in the hand of John Westwyk by Kari Anne Rand in 2014. Further evidence for Westwyk's authorship was revealed by Seb Falk in a book published in 2020.
Debate
Price published an abstract in 1953, and the whole text (facsimile, transcription, and studies of the manuscript) in 1955. He maintained the possibility that Chaucer authored the Equatorie, possibly as the missing part of his A Treatise on the Astrolabe, which describes the astrolabe; the Equatorie makes direct reference to it. He argued that the manuscript was a holograph draft, written in the hand of its author, as shown by the many additions and corrections in the manuscript.
Price offered five points as indicators of Chaucer's authorship:
Style and scientific treatment of the material are similar to A Treatise on the Astrolabe;
The text mentions that the year 1392 is the "Radix" (or "root") of Chaucer;
The main hand (including that of the "Radix" note) resembled, Price thought, a document likely written in Chaucer's hand;
Linguistic similarities between the Equatorie and Chaucer's work, including "verbal echoes of the Astrolabe;
The author is influenced by Merton's school of astronomy but lives in London, and the writing is that of an amateur, not a professional astronomer; in addition, the writer is familiar with "the diplomatic cipher methods of his time"—all elements that correspond with Chaucer's biography.
Following the publication of the facsimile and transcription, G. Herdan published an article in which he concluded, based upon the percentage of words in the Equatorie of "Romance vocabulary" (which includes words from Old French, Anglo-Norman French, and Latin), that Chaucer was indeed the author: "The agreement between observation and expectation, or between fact and theory, is so striking that without going further into the question of statistical significance we may conclude that by the token of Romance vocabulary the Equatorie is to be regarded as a work by Chaucer".
However, Price's arguments were challenged in various ways. His claim that the manuscript was a draft in the hand of its author was disputed, though ultimately the evidence does seem to support it. More significantly, Price's claim that the handwriting was that of Geoffrey Chaucer was disproved by analysis by Kari Anne Rand Schmidt.
In 2014 Kari Anne Rand identified the hand as belonging to John Westwyk.
Content
The text describes the construction of an equatorium, an instrument comparable to the astrolabe – but where an astrolabe shows the positions of the stars, an equatorium computes them for the planets, according to the Geocentric model of Ptolemy. The instrument is constructed from two discs, six feet in diameter. One of them is solid, and is marked with characteristics of the orbits of the various planets: their apogee, their equants, and other centres. The other disc consists of "a ring, a diametral bar, and a rule pivoted at the centre of the bar". The two discs are joined and simulate the motions of each of the planets. A divided circle around the rims of the two discs allow for the transferral of information from sets of tables (the Alfonsine tables, from a Parisian document) that contain the data for each planet.
The design was based on earlier equatoria, but refined for greater ease of manufacture and use. It permits the user to find the longitudes of any classical planet (including the Sun and Moon, as well as the lunar latitude).
Cipher
A cipher is used for some comments on the tables, and Price gave the key. He could not, however, discern what the rationale of or the ordering behind the key was – whether it was perhaps based on some medieval version of the Greek alphabet, or whether there was "some key-phrase or sentence such as a name or family motto" behind it.
References
Notes
Bibliography
External links
Cambridge Digital Library: Equatorie of the Planetis Digitised images, transcription, translation & virtual model of Peterhouse MS 75.I.
Seb Falk: What's the difference between an astrolabe and an equatorium Blog post.
14th-century books
Works by Geoffrey Chaucer
Astronomy books
Middle English literature | The Equatorie of the Planetis | [
"Astronomy"
] | 1,669 | [
"Astronomy books",
"Works about astronomy"
] |
62,527,600 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20amarillans | Epichloë amarillans is a haploid sexual species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 1994, Epichloë amarillans is a sister lineage to Epichloë baconii, Epichloë festucae, Epichloë mollis and Epichloë stromatolonga.
Epichloë amarillans is found in North America, where it has been identified in many species of grasses, including Agrostis hyemalis, Agrostis perennans, Calamagrostis canadensis, Elymus virginicus, Sphenopholis nitida, Sphenopholis obtusata, Sphenopholis × pallens and Ammophila breviligulata.
References
amarillans
Fungi described in 1994
Fungi of North America
Fungus species | Epichloë amarillans | [
"Biology"
] | 183 | [
"Fungi",
"Fungus species"
] |
62,527,611 | https://en.wikipedia.org/wiki/Affect%20priming | Affective priming, also called affect priming, is a type of response priming and was first proposed by Russell H. Fazio. This type of priming entails the evaluation of people, ideas, objects, goods, etc., not only based on the physical features of those things, but also on affective context. The affective context may come from previous life experiences, and therefore, primes may arouse emotions rather than ideas. Most research and concepts about affective priming derive from the affective priming paradigm, which looks to make judgments of neutral affective targets following positive, neutral, or negative primes. A prominent derivation of affective priming paradigm is the Affect Misattribution Procedure (AMP), developed by Payne, Cheng, Govorun, and Stewart. The main idea of AMP is to measure implicit attitudes, therefore, if the evaluation of the prime stimuli of an object is positive, it is said that the person has a positive attitude toward the object exposed.
Affective priming paradigm
The intent of this affective priming paradigm had initially the intent of eliminating the bias created by affective priming research self-reports. As a consequence, Fazio created the affective priming paradigm, which focuses on the evaluation of automatic stimuli. One finding of studies that use this paradigm says that “performance is typically faster and more accurate when a prime and target are congruent and have the same emotional information (e.g., “flower”–“wedding”) compared with when they are incongruent and have different emotional information (e.g., “party’ –“corpse”).”
Affective automatic response
Affective priming has been long said to be related to implicit attitudes . Some research suggests that affective priming is triggered by multiple, simultaneous mechanisms. Added to this, it has found that deeper processing of the target being evaluated can significantly hinder the influence of the prime. On the other hand, deeper processing prime significantly increases the prime's influence and it is retrieved more easily in subsequent occasions.
There is still a great need of research related to affective priming and automatic processing. Some arguments in favor of a strong relationship between the two argue that these affective priming processes 1) lack intentionality, 2) are highly efficient, 3) have reduced controllability, 4) are triggered at a high speed, especially when there is a motivationally relevant stimulus, and 5) there is reduced awareness of the origin, meaning, and occurrence of the response.
Seib-Pfeifer and Gibbons have suggested that affective priming processing is linked to the right central-to-parieto-occipital positive slow wave (PSW).
Other factors that contribute to this relationship between affective priming and automatic processing include switching tasks, salience asymmetry, and potentially strategic recoding.
Valence vs arousal
There is much discussion in the world of psychology about the effects of valence and arousal in affect priming, since they both seem to affect it, but there has been little research on which of the two has a greater effect on this type of priming. For example, one study by Yao, Shu, and Luo asserts that valence has a greater effect, based on their findings regarding the stability of valence-driven priming effects against arousal-driven effects and their information in the semantic system.
References
Social psychology
Cognitive psychology | Affect priming | [
"Biology"
] | 704 | [
"Behavioural sciences",
"Behavior",
"Cognitive psychology"
] |
62,528,438 | https://en.wikipedia.org/wiki/Evelyn%20Lip | Evelyn Lip (born 1938) is a Malaysian architecture scholar and Feng shui consultant.
She is the author of fifty eight books on architecture, Chinese geomancy, and children's stories. Dr. Lip has completed nearly one thousand illustrations and paintings featured in her books.
Dr. Lip was a lecturer for 31 years in the Department of Architecture at the National University of Singapore before retiring at the age of 60. She specializes in Chinese architecture and applies geomancy to her practice.
Dr. Lip has given around 160 public speeches in Singapore and abroad on traditional Chinese architecture, Feng shui and Chinese art and culture.
In 1989, the Singapore Tourist Promotion Board together with its American counterpart, organised a 32-day publicity tour covering 9 American cities. Dr. Lip was part of a delegation of six specialists from various fields who travelled to the US to promote the art, culture and conservation efforts of Singapore.
Qualifications
PhD in Architecture
Master in Architecture
Professional Dip Architecture
Dip Building Design
Dip Interior Design
Two years at the Nanyang Academy of Fine Arts on Chinese Brush Painting
Works
Featured in: Meetings with Remarkable Asian Women (2012) Quicksilver Books. ASIN B007YCEXZA
Author: Feng Shui for Harmony in the Home (2010) Cavendish Square Publishing.
Author: Your Face is Your Fortune (2010) Cavendish Square Publishing.
Author: All You Need to Know about Feng Shui (2009) Cavendish Square Publishing.
Author: Feng Shui for Success in Business (2009) Cavendish Square Publishing.
Author: Feng Shui in Chinese Architecture (2009) Cavendish Square Publishing.
Author: Personalise your Feng Shui and Transform your Life (2009) Cavendish Square Publishing.
Author: Chinese Practices and Beliefs (2001) Heian International.
Author: Design and Feng Shui of Logos, Trademarks and Signboards (1998) Stone Bridge Press.
Author: Personalize your Feng Shui: A Step by Step Guide to the Pillars of Destiny (1997) Heian International.
Author: 1000 Character Classic (1997) Raffles Editions.
Author: Feng Shui for Business (1995) Times Editions.
Author: Feng Shui: Environments of Power - A Study of Chinese Architecture (1995) Wiley.
Author: Fun with Astrology (1994) Graham Brash.
Author: Out of China (1993) Addison-Wesley.
Author: Chinese Geomancy (1992) Times Books International.
Author: Chinese Numbers (1992) Heian International.
Author: Feng Shui for the Home (1990) Heian International.
Author: Feng Shui for the Business (1989) Stone Bridge Press.
Author: Choosing Auspicious Chinese Names (1988) Stone Bridge Press.
Author: Feng Shui: A Layman's Guide to Chinese Geomancy (1987) Times Books International.
Author: Notes on Things Chinese (1986) Federal Publications.
Author: Chinese Beliefs and Superstitions (1985) Graham Brash.
Author: Chinese Proverbs and Sayings (1984) Graham Brash.
Author: Chinese Temples and Deities (1981) Times Books International.
Author: The Fairy Princess (1981) Macmillan Education Ltd.
References
1938 births
Living people
Malaysian women artists
Malaysian architects
20th-century Malaysian architects
20th-century Malaysian artists
21st-century Malaysian artists
Malaysian children's writers
Academic staff of the National University of Singapore
Architecture writers
Malaysian emigrants to Singapore | Evelyn Lip | [
"Engineering"
] | 674 | [
"Architecture writers",
"Architecture"
] |
62,528,566 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20baconii | Epichloë baconii is a haploid sexual species in the fungal genus Epichloë.
A systemic grass symbiont first described in 1993, Epichloë baconii is a sister lineage to Epichloë stromatolonga.
Epichloë baconii is found in Europe, where it has been identified in many species of grasses, including Agrostis capillaris, Agrostis stolonifera, Calamagrostis villosa, Calamagrostis varia and Calamagrostis purpurea.
References
baconii
Fungi described in 1993
Fungi of Europe
Fungus species | Epichloë baconii | [
"Biology"
] | 129 | [
"Fungi",
"Fungus species"
] |
62,528,636 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20sylvatica | Epichloë sylvatica is a haploid sexual species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 1998, Epichloë sylvatica forms a clade within the Epichloë typhina complex.
Epichloë sylvatica is found from Europe to Asia, where it has been identified in association with two grass species, Brachypodium sylvaticum and Hordelymus europaeus.
Subspecies
Epichloë sylvatica has one subspecies, Epichloë sylvatica subsp. pollinensis Leuchtm. & M. Oberhofer. Described in 2013, Epichloë sylvatica subsp. pollinensis has been found in Europe in the grass species Hordelymus europaeus.
References
sylvatica
Fungi described in 1998
Fungi of Asia
Fungi of Europe
Fungus species | Epichloë sylvatica | [
"Biology"
] | 179 | [
"Fungi",
"Fungus species"
] |
62,528,650 | https://en.wikipedia.org/wiki/Central%20configuration | In celestial mechanics, a central configuration is a system of point masses with the property that each mass is pulled by the combined gravitational force of the system directly towards the center of mass, with acceleration proportional to its distance from the center. Central configurations are studied in -body problems formulated in Euclidean spaces of any dimension, although only dimensions one, two, and three are directly relevant for celestial mechanics in physical space.
Examples
For equal masses, one possible central configuration places the masses at the vertices of a regular polygon (forming a Klemperer rosette), a Platonic solid, or a regular polytope in higher dimensions. The centrality of the configuration follows from its symmetry. It is also possible to place an additional point, of arbitrary mass, at the center of mass of the system without changing its centrality.
Placing three masses in an equilateral triangle, four at the vertices of a regular tetrahedron, or more generally masses at the vertices of a regular simplex produces a central configuration even when the masses are not equal. This is the only central configuration for these masses that does not lie in a lower-dimensional subspace.
Dynamics
Under Newton's law of universal gravitation, bodies placed at rest in a central configuration will maintain the configuration as they collapse to a collision at their center of mass. Systems of bodies in a two-dimensional central configuration can orbit stably around their center of mass, maintaining their relative positions, with circular orbits around the center of mass or in elliptical orbits with the center of mass at a focus of the ellipse. These are the only possible stable orbits in three-dimensional space in which the system of particles always remains similar to its initial configuration.
More generally, any system of particles moving under Newtonian gravitation that all collide at a single point in time and space will approximate a central configuration, in the limit as time tends to the collision time. Similarly, a system of particles that eventually all escape each other at exactly the escape velocity will approximate a central configuration in the limit as time tends to infinity. And any system of particles that move under Newtonian gravitation as if they are a rigid body must do so in a central configuration. Vortices in two-dimensional fluid dynamics, such as large storm systems on the Earth's oceans, also tend to arrange themselves in central configurations.
Enumeration
Two central configurations are considered to be equivalent if they are similar, that is, they can be transformed into each other by some combination of rotation, translation, and scaling.
With this definition of equivalence, there is only one configuration of one or two points, and it is always central.
In the case of three bodies, there are three one-dimensional central configurations, found by Leonhard Euler. The finiteness of the set of three-point central configurations was shown by Joseph-Louis Lagrange in his solution to the three-body problem; Lagrange showed that there is only one non-collinear central configuration, in which the three points form the vertices of an equilateral triangle.
Four points in any dimension have only finitely many central configurations. The number of configurations in this case is at least 32 and at most 8472, depending on the masses of the points. The only convex central configuration of four equal masses is a square. The only central configuration of four masses that spans three dimensions is the configuration formed by the vertices of a regular tetrahedron.
For arbitrarily many points in one dimension, there are again only finitely many solutions, one for each of the linear orderings (up to reversal of the ordering) of the points on a line.
For every set of point masses, and every dimension less than , there exists at least one central configuration of that dimension.
For almost all -tuples of masses there are finitely many "Dziobek" configurations that span exactly dimensions.
It is an unsolved problem, posed by and , whether there is always a bounded number of central configurations for five or more masses in two or more dimensions. In 1998, Stephen Smale included this problem as the sixth in his list of "mathematical problems for the next century". As partial progress, for almost all 5-tuples of masses, there are only a bounded number of two-dimensional central configurations of five points.
Special classes of configurations
Stacked
A central configuration is said to be stacked if a subset of three or more of its masses also form a central configuration. For example, this can be true for equal masses forming a square pyramid, with the four masses at the base of the pyramid also forming a central configuration, or for masses forming a triangular bipyramid, with the three masses in the central triangle of the bipyramid also forming a central configuration.
Spiderweb
A spiderweb central configuration is a configuration in which the masses lie at the intersection points of a collection of concentric circles with another collection of lines, meeting at the center of the circles with equal angles. The intersection points of the lines with a single circle should all be occupied by points of equal mass, but the masses may vary from circle to circle. An additional mass (which may be zero) is placed at the center of the system.
For any desired number of lines, number of circles, and profile of the masses on each concentric circle of a spiderweb central configuration, it is possible to find a spiderweb central configuration matching those parameters.
One can similarly obtain central configurations for families of nested Platonic solids, or more generally group-theoretic orbits of any finite subgroup of the orthogonal group.
James Clerk Maxwell suggested that a special case of these configurations with one circle, a massive central body, and much lighter bodies at equally spaced points on the circle could be used to understand the motion of the rings of Saturn. used stable orbits generated from spiderweb central configurations with known mass distribution to test the accuracy of classical estimation methods for the mass distribution of galaxies. His results showed that these methods could be quite inaccurate, potentially showing that less dark matter is needed to predict galactic motion than standard theories predict.
References
Classical mechanics
Orbits | Central configuration | [
"Physics"
] | 1,249 | [
"Mechanics",
"Classical mechanics"
] |
62,528,684 | https://en.wikipedia.org/wiki/Climate%20target | A climate target, climate goal or climate pledge is a measurable long-term commitment for climate policy and energy policy with the aim of limiting the climate change. Researchers within, among others, the UN climate panel have identified probable consequences of global warming for people and nature at different levels of warming. Based on this, politicians in a large number of countries have agreed on temperature targets for warming, which is the basis for scientifically calculated carbon budgets and ways to achieve these targets. This in turn forms the basis for politically decided global and national emission targets for greenhouse gases, targets for fossil-free energy production and efficient energy use, and for the extent of planned measures for climate change mitigation and adaptation.
At least 164 countries have implemented climate targets in their national climate legislation.
Global climate targets
Global climate targets are goals that a large number of countries have agreed upon, including at United Nations Climate Change conferences (COP). Targets often referred to are:
The Climate Convention – an international environmental treaty adopted at the Rio Conference in Brazil in 1992.
Targets for 2008 to 2012: In the Kyoto Protocol of 1997, 160 countries committed to reducing their greenhouse gas emissions by an average of 5.2 percent over the period 2008 to 2012 compared to 1990 levels.
Targets for 2013 to 2020: In the Doha amendment to the Kyoto Protocol, slightly fewer I countries committed to reducing their emissions by at least 18 percent in the period 2013 to 2020 compared to 1990.
Targets for 2030:
105 countries promised deforestation at the COP26 in 2021 to end deforestation to 2030.
105 countries signed in connection with COP26 and COP27 a pledge to reduce methane emissions by 30 percent by 2030 compared to 2020.
Targets for 2100:
United Nations Climate Change Conference 2009 proposed a 2 degree climate target for global warming until the year 2100.
The Paris Agreement (United Nations Climate Change Agreement) of 2015 with countries' non-binding climate pledges, formally known as NDCs, and before the agreement's ratification for INDCs (Intended Nationally Determined Contributions), to keep global warming well below the 2-degree target by 2100, and that further efforts should be made towards a 1.5-degree target.
Goal number 13 in the global goals for sustainable development within the Agenda 2030 deals with climate action, and was decided by the UN General Assembly in 2015. Among other things, it includes the UN Green Climate Fund.
Calculation of Emissions Targets
An emissions target or greenhouse gas emissions reduction target is a central policy instrument of international greenhouse gas emissions reduction politics and a key pillar of climate policy. They typically include heavy consideration of emissions budgets, which are calculated using rate of warming per standard emission of carbon dioxide, a historic baseline temperature, a desired level of confidence and a target global average temperature to stay below.
An "emissions target" may be distinguished from an emissions budget, as an emissions target may be internationally or nationally set in accordance with objectives other than a specific global temperature. This includes targets created for their political palatability, rather than budgets scientifically determined to meet a specific temperature target.
A country's determination of emissions targets is based on careful consideration of pledged NDCs (nationally determined contributions), economic and social feasibility, and political palatability. Carbon budgets can provide political entities with knowledge of how much carbon can be emitted before likely reaching a certain temperature threshold, but specific emissions targets take more into account. The exact way these targets are determined varies widely from country to country. Variation in emissions targets and time to complete them depends on factors such as accounting of land-use emissions, afforestation capacity of a country, and a countries transport emissions. Importantly, emissions targets also depend on their hypothesized reception.
Many emissions pathways, budgets and targets also rely on the implementation of negative emissions technology. These currently undeveloped technologies are predicted to pull net emissions down even as source emissions are not reduced.
Effectiveness of Targets
Many countries' emissions targets are above the scientifically calculated allowable emissions to remain below a certain temperature threshold. In 2015, many countries pledged NDCs to limit the increase in the global average temperature to well below 2 °C above pre-industrial levels. Many of the largest emitters of GHGs, however, are on track to push global average temperature to as much as 4 °C. Some of these projections contradict agreements made in the 2015 Paris Agreement, meaning countries are not keeping to their pledged NDCs.
In addition, it is uncertain how effective many emissions targets and accompanying policies really are. For example, with countries that have high consumption-based carbon emissions, strictly enforced, aligned and coordinated international policy measures determine the effectiveness of targets. In addition, many ambitious policies are proposed and passed but are not practically enforced or regulated, or have unintended consequences. China's ETS (emissions trading scheme), while seeming to have an effect on reducing production-based emissions also promoted outsourcing of emissions contributing to a further imbalance of carbon transfer among China's different provinces. The ETS evaluation also did not account for exported consumption-based emissions.
Many countries aim to reach net zero emissions in the next few decades. In order to reach this goal however, there must be a radical shift in energy infrastructure. For example, in the United States, political entities are attempting to switch away from coal and oil based energy by replacing plants with natural gas combined cycle (NGCC) power plants. Other countries like the Netherlands were obligated by the District Court of Hague to reduce its greenhouse gas emissions by 25% by 2020. The Court has passed other innovations (Milieudefensie v. Royal Dutch Shell) to reduce dioxide emissions by 45% by 2030. However many find this transition to not be significant enough to reach net-zero emissions. More significant changes, for example using biomass energy with carbon capture and storage (BECCS) are suggested as a viable option to transition to net-zero emissions countries.
See also
Climate change in Europe#Climate targets
Intergovernmental Panel on Climate Change
United Nations Climate Change conference
Nationally Determined Contributions
Bioenergy with Carbon Capture and Storage
Paris Agreement
List of countries by greenhouse gas emissions per capita
References
Notes
Greenhouse gas emissions
Environmental science | Climate target | [
"Chemistry",
"Environmental_science"
] | 1,255 | [
"Greenhouse gases",
"Greenhouse gas emissions",
"nan"
] |
62,528,817 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20brachyelytri | Epichloë brachyelytri is a haploid sexual species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 1999, Epichloë brachyelytri is a sister lineage to Epichloë aotearoae. Epichloe" grass endophytes comprise group of filamentous fungi of both sexual and asexual species.
Epichloë brachyelytri is found in North America, where it has been identified in the grass species Brachyelytrum erectum. To date six Eurasian's and one North American morphospecies have been described, and these approximately corresponding to six distinct mating populations. Often Epichloe" confer to their host a range of fitness benefits, including enhanced resistance to biotic and abiotic stresses. One such benefit is defense against plant herbivore that is attributable to various alkaloids produced by these fungi.
References
brachyelytri
Fungi described in 1999
Fungi of North America
Fungus species | Epichloë brachyelytri | [
"Biology"
] | 214 | [
"Fungi",
"Fungus species"
] |
62,528,873 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20bromicola | Epichloë bromicola is a haploid sexual species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 1998, Epichloë bromicola is a sister lineage to Epichloë elymi.
Epichloë bromicola is found from Europe to Asia, where it has been identified in many species of grasses. In Europe, it has been associated with Bromus benekenii, Bromus erectus, Bromus ramosus, Elymus repens, Hordelymus europaeus and Hordeum brevisubulatum. In Asia, it has been found in Leymus chinensis and Elymus tsukushiensis. The sexual phase has been observed on Bromus erectus, Elymus repens and Elymus tsukushiensis. Seed transmission has been seen in Bromus benekenii, Bromus ramosus, Hordelymus europaeus, Hordeum brevisubulatum, Leymus chinensis and Elymus tsukushiensis, but is known to be absent in Bromus erectus and Elymus repens.
References
bromicola
Fungi described in 1998
Fungi of Asia
Fungi of Europe
Fungus species | Epichloë bromicola | [
"Biology"
] | 248 | [
"Fungi",
"Fungus species"
] |
62,528,913 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20elymi | Epichloë elymi is a haploid sexual species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 1999, Epichloë elymi is a sister lineage to Epichloë bromicola.
Epichloë elymi is found in North America, where it has been identified in Bromus kalmii and some species of Elymus, including E. patula and E. virginicus.
References
elymi
Fungi described in 1999
Fungi of North America
Fungus species | Epichloë elymi | [
"Biology"
] | 109 | [
"Fungi",
"Fungus species"
] |
62,528,999 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20gansuensis | Epichloë gansuensis is a haploid species in the fungal genus Epichloë. The sexual phase has not been observed.
A systemic and seed-transmissible grass symbiont first described in 2004, Epichloë gansuensis is a sister lineage to Epichloë sibirica and an early branching lineage on the Epichloë tree.
Epichloë gansuensis is found in Asia, where it has been identified in the grass species Achnatherum inebrians, Achnatherum sibiricum and Achnatherum pekinense.
Varieties
Epichloë gansuensis has one variety.
Epichloë gansuensis subsp. inebrians (C.D. Moon & Schardl) Schardl was first described in 2007. It is found in Asia in the grass species Achnatherum inebrians.
References
gansuensis
Fungi described in 2004
Fungi of Asia
Fungus species | Epichloë gansuensis | [
"Biology"
] | 196 | [
"Fungi",
"Fungus species"
] |
62,529,077 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20glyceriae | Epichloë glyceriae is a haploid sexual species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 1999, Epichloë glyceriae is an early branching lineage on the Epichloë tree.
Epichloë glyceriae is found in North America, where it has been identified in grass species of the genus Glyceria. Epichloë glyceriae is not thought to be seed transmitted.
References
glyceriae
Fungi described in 1999
Fungi of North America
Fungus species | Epichloë glyceriae | [
"Biology"
] | 119 | [
"Fungi",
"Fungus species"
] |
62,529,107 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20mollis | Epichloë mollis is a haploid sexual species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 1982, Epichloë mollis is a sister lineage to Epichloë amarillans, Epichloë baconii, Epichloë festucae and Epichloë stromatolonga.
Epichloë mollis is found in Europe, where it has been identified in the grass species Holcus mollis.
References
mollis
Fungi described in 1982
Fungi of Europe
Fungus species | Epichloë mollis | [
"Biology"
] | 115 | [
"Fungi",
"Fungus species"
] |
62,529,155 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20sibirica | Epichloë sibirica is a haploid species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 2009, Epichloë sibirica is a sister lineage to Epichloë gansuensis and an early branching clade on the Epichloë tree.
Epichloë sibirica is found in Asia, where it has been identified in the grass species Achnatherum sibiricum. Epichloë sibirica is not known to be sexual.
References
sibirica
Fungi described in 2009
Fungi of Asia
Fungus species | Epichloë sibirica | [
"Biology"
] | 123 | [
"Fungi",
"Fungus species"
] |
62,529,175 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20stromatolonga | Epichloë stromatolonga is a haploid species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 2009, Epichloë stromatolonga is a sister lineage to Epichloë amarillans, Epichloë baconii, Epichloë festucae and Epichloë mollis.
Epichloë stromatolonga is found in Asia, where it has been identified in the grass species Calamagrostis epigejos. Epichloë stromatolonga is not known to have a sexual phase.
References
stromatolonga
Fungi described in 2009
Fungi of Asia
Fungus species | Epichloë stromatolonga | [
"Biology"
] | 143 | [
"Fungi",
"Fungus species"
] |
62,530,331 | https://en.wikipedia.org/wiki/Tait%E2%80%93Kneser%20theorem | In differential geometry, the Tait–Kneser theorem states that, if a smooth plane curve has monotonic curvature, then the osculating circles of the curve are disjoint and nested within each other.
The logarithmic spiral or the pictured Archimedean spiral provide examples of curves whose curvature is monotonic for the entire curve. This monotonicity cannot happen for a simple closed curve (by the four-vertex theorem, there are at least four vertices where the curvature reaches an extreme point) but for such curves the theorem can be applied to the arcs of the curves between its vertices.
The theorem is named after Peter Tait, who published it in 1896, and Adolf Kneser, who rediscovered it and published it in 1912. Tait's proof follows simply from the properties of the evolute, the curve traced out by the centers of osculating circles.
For curves with monotone curvature, the arc length along the evolute between two centers equals the difference in radii of the corresponding circles.
This arc length must be greater than the straight-line distance between the same two centers, so the two circles have centers closer together than the difference of their radii, from which the theorem follows.
Analogous disjointness theorems can be proved for the family of Taylor polynomials of a given smooth function, and for the osculating conics to a given smooth curve.
References
Theorems in differential geometry | Tait–Kneser theorem | [
"Mathematics"
] | 301 | [
"Theorems in differential geometry",
"Theorems in geometry"
] |
62,530,340 | https://en.wikipedia.org/wiki/Masoud%20Soleimani | Masoud Soleimani (; born 31 August 1970) is an Iranian medical professor. He was imprisoned in the United States on October 25, 2018, pending trial. He was held until his release on December. The crime he was charged for would usually result in fine but in this case the imprisonment seemed to be politically motivated. "I don’t see any evidence that there was criminal intent here," says Clif Burns, a lawyer at Crowell & Moring in Washington DC who specializes in national-security law, including export controls and trade sanctions.[3][4].11, 2019, in a prisoner swap for Xiyue Wang.On December 8, 2019, president Donald Trump thanked Tehran for "a very fair negotiation" and said: "See, we can make a deal together!".[6] Soleimani had been invited by the Mayo Clinic in Minnesota to lead a research program; upon his arrival in the United States, he was arrested and transferred to a prison in Atlanta. Following the prisoner swap, charges were then dismissed.
Detention in the United States
Professor Masoud Soleimani traveled to the US in autumn 2018, where he planned to complete the final stage of his research on treating stroke patients as a visiting scholar at the prestigious Mayo Clinic in Minnesota.
He was arrested upon landing in Chicago. Prosecutors in Atlanta accused him and two of his former students of conspiring and attempting to export human growth factors from the US to Iran without authorization.
According to court documents, Soleimani's former student Mahboobe Ghaedi bought growth factors on his behalf in early 2016. At the time, Ghaedi was a researcher in laboratory medicine at Yale School of Medicine in New Haven, Connecticut. Now a principal scientist at the pharmaceutical firm AstraZeneca in Gaithersburg, Maryland, Ghaedi told Nature that she purchased the proteins in part because they are cheaper and more readily available in the United States than in Iran.
Ghaedi then sent the vials to another former student of Soleimani's, Maryam Jazayeri, a biochemist in Louisville, Kentucky. Jazayeri had agreed to take the growth factors to Soleimani during her next trip to visit family in Iran. But when she tried to board her plane at the Atlanta airport in September 2016, US border agents searched her luggage and confiscated the growth factors.
Jazayeri had no further contact with US law-enforcement officials until February 2018, when she was again stopped by border agents at the Atlanta airport. They asked her about the vials they had confiscated in 2016, and Jazayeri said that she had agreed to transport the growth factors to Soleimani as a favor, without knowing that this was prohibited. According to court documents, she also told the agents that the proteins were to be used for "medical purposes such as stem cell research, cancer research, and transplantation".
Eight months later, on 24 October 2018, a federal grand jury indicted all three scientists under seal — or behind closed doors — on two counts of conspiring to export goods to Iran without authorization. At the time, Soleimani was en route to the United States to take up a temporary research position at the Mayo Clinic in Rochester, Minnesota. Federal agents arrested him when he arrived in the United States on 25 October, and the government also revoked his visa. Ghaedi, a US permanent resident, and Jazayeri, a US citizen who was born in Iran, were arrested soon afterwards.
The crime he was charged for would usually result in fine but in this case the imprisonment seemed to be politically motivated. "I don’t see any evidence that there was criminal intent here," says Clif Burns, a lawyer at Crowell & Moring in Washington DC who specializes in national-security law, including export controls and trade sanctions. The attorneys for Jazayeri filed a motion to dismiss the charges, arguing that the Iranian sanctions were unconstitutionally vague as applied to the growth factors Jazayeri had in her possession and that, regardless, the growth factors were exempted from the export ban because they had a medicinal purpose.
On December 8, 2019, president Donald Trump thanked Tehran for "a very fair negotiation" and said: "See, we can make a deal together!". The charges against Jazayeri and Ghaedi were subsequently dropped.
References
External links
1970 births
Living people
Scientists from Isfahan
Iranian hematologists
University of Tehran alumni
Tarbiat Modares University alumni
Academic staff of Tarbiat Modares University
21st-century biologists
Stem cell researchers
Iranian people imprisoned in the United States | Masoud Soleimani | [
"Biology"
] | 950 | [
"Stem cell researchers",
"Stem cell research"
] |
62,530,454 | https://en.wikipedia.org/wiki/Polyestradiol%20phosphate/medroxyprogesterone%20acetate | Polyestradiol phosphate/medroxyprogesterone acetate (PEP/MPA) is a combination of polyestradiol phosphate (PEP), an estrogen, and medroxyprogesterone acetate (MPA), a progestin, which was studied in the 1960s as a long-lasting combined injectable contraceptive for women but was never marketed. It was administered by intramuscular injection once every 3 months and contained 40 mg PEP and 150 mg MPA. The combination was studied in a sample of 99 premenopausal women and was found to be effective in preventing pregnancy, but caused menstrual irregularities similar to those of MPA alone as a progestogen-only injectable contraceptive. PEP was included in the formulation to prevent estrogen deficiency and reduce menstrual abnormalities caused by MPA during long-term contraceptive therapy.
See also
Estradiol undecylate/norethisterone enanthate
List of combined sex-hormonal preparations § Estrogens and progestogens
References
Abandoned drugs
Combined injectable contraceptives | Polyestradiol phosphate/medroxyprogesterone acetate | [
"Chemistry"
] | 236 | [
"Drug safety",
"Abandoned drugs"
] |
72,137,240 | https://en.wikipedia.org/wiki/Crime-Free%20Multi-Housing | The Crime-Free Multi-Housing (CFMH) program is a crime-free ordinance program, which partners property owners, residents, and law-enforcement personnel in an effort to eliminate crime, drugs, and gang activity from rental properties.
History
The program began in Mesa, Arizona in the United States in 1992. Since then, it has spread to other US cities and several other countries.
The International Crime Free Association reports potential benefits of the program, including tenant satisfaction and increased demand for rental units.
Additionally, there has been pushback against crime free ordinances. In federal lawsuits across the country, tenants, landlords, and the Department of Justice (DOJ) have challenged crime-free ordinances and their enforcement, citing violations of fair housing laws, equal protection, due process, and the First Amendment right to free association.
Program
Three phases must be completed under police supervision:
An eight-hour seminar presented by the local police department
Certification that the rental property has met the security requirements for the tenants' safety
A tenant crime-prevention meeting is held
Participating landlords have the option to display their certification status on their property.
See also
Crime prevention through environmental design
Nuisance ordinance
Eviction in the United States § Disproportionately impacted evictees
Racial inequality in the United States § Housing
Notes
References
External links
Crime Free Housing Training, West Fargo, ND
Crime-Free-Multi-Housing, City of Ottawa, Ontario, Canada
Crime Free Multi-Housing Program, British Columbia, Canada
Crime Free Multi-Housing, Tucson, AZ
EPD Crime Free Multi-Housing Program, Evansville, IN
Criminology
Security engineering
Crime prevention
Housing in the United States
Housing legislation | Crime-Free Multi-Housing | [
"Engineering"
] | 340 | [
"Systems engineering",
"Security engineering"
] |
72,138,661 | https://en.wikipedia.org/wiki/Jonyang%20GDG130 | The Jonyang GDG130 is a military engineering vehicle built by China's Guizhou Jonyang Kinetics Co. Ltd. (Jonyang). It is based on the High-Speed Engineer Vehicle (HSEV) developed by Australian Defence Industries (ADI), now known as Thales Australia designed for the Australian Army.
It is currently the main engineering backhoe loader of the People's Liberation Army.
The GDG130 is also the basis for Jonyang's JYL313-B civilian backhoe loader.
Design
The Jonyang GDG130 was based on the High-Speed Engineer Vehicle (HSEV) developed by Australian Defence Industries (ADI), now known as Thales Australia.
In 2004, ADI started a partnership with China's Guizhou Jonyang Kinetics, which builds construction wheeled and tracked excavators and established a license production of the Australian HSEV. ADI sent 30 HSEV knock-down kits for local assembly in China by Jonyang.
The GDG130 are license production models with modifications over the original HSEV to meet the requirements of the People's Liberation Army, as well as for the civilian construction market, which Jonyang markets as the JYL313-B backhoe loader.
As a military engineer vehicle, the GDG130 is used to perform a variety of field engineering missions to support heavy combat units, including constructing trenches and defensive positions, clearing obstacles and filling ditches, as well as constructing obstacles and supporting construction work.
It is equipped with a 0.2 cubic meter backhoe bucket which can dig up trenches up to 4 meters deep, and a 0.8 cubic meter loader bucket which can be used to plough obstacles, and can be fitted with attachments and can be used as a forklift, compactor, or auger.
Some variants are fitted with an armored cabin, which includes bulletproof glass windows to protect from small caliber rounds and shrapnel, but is not equipped with any defensive weapons.
Like the ADI HSEV, the GSG130 is powered by a Cummnis 6BTA5.9C 5.9 liter turbocharged diesel engine with a maximum output of 185 horsepower and can attain a maximum speed of 90 kilometers per hour on road, and tow a trailer with a maximum weight of 8 tonnes. It also has an all-wheel drive system and can be used over rough terrain.
Operators
References
Military vehicles of the People's Republic of China
Military engineering vehicles
People's Liberation Army | Jonyang GDG130 | [
"Engineering"
] | 522 | [
"Engineering vehicles",
"Military engineering",
"Military engineering vehicles"
] |
72,140,494 | https://en.wikipedia.org/wiki/Hartley%20V8%20engine | The Hartley V8 engine is a series of a four-stroke naturally-aspirated DOHC V8 engines, designed, developed and built by American John Hartley and Hartley Enterprises, which has been produced since 2004. It was famously used in the well-known Ariel Atom 500 V8 sports car model.
References
Automobile engines
Internal combustion piston engines
V8 engines
Gasoline engines by model
Engines by model | Hartley V8 engine | [
"Technology"
] | 77 | [
"Engines by model",
"Engines",
"Automobile engines"
] |
72,140,557 | https://en.wikipedia.org/wiki/Coachella%20filter | The Coachella filter was an augmented reality social media camera filter released April 2016 that superimposed a flower crown on the user's head and brightened the complexion of the user's skin. The filter appeared on the Snapchat photo messaging application on the occasion of the Coachella music festival in 2016, using the festival's recognizable "boho-chic aesthetic." The Coachella filter became popular worldwide.
The filter was criticized for whitewashing users' skin complexion and contributing to unrealistic beauty standards and dysmorphia.
References
Social media
Popular culture
2016
Internet culture | Coachella filter | [
"Technology"
] | 122 | [
"Computing and society",
"Social media"
] |
72,142,270 | https://en.wikipedia.org/wiki/Thiophosphoryl%20bromide | Thiophosphoryl bromide is an inorganic compound with the formula .
Preparation
Thiophosphoryl bromide can be prepared by heating phosphorus tribromide with phosphorus pentasulfide, or with elemental sulfur in an inert atmosphere at 130 °C.
Thiophosphoryl bromide is one product of the bromination of in cold carbon disulfide:
Structure and properties
Thiophosphoryl bromide has tetrahedral molecular geometry and C3v molecular symmetry. According to gas electron diffraction, the phosphorus–sulfur bond length is 1.895 Å and the phosphorus–bromine bond length is 2.193 Å, while the bond angle is 116.2° and the bond angle is 101.9°.
Thiophosphoryl bromide is soluble in carbon disulfide, chloroform and diethyl ether.
Reactions
Like other phosphoryl and thiophosphoryl halides, thiophosphoryl bromide readily hydrolyses, undergoes nucleophilic substitution and forms adducts with Lewis acids. Reaction with lithium iodide generates the mixed thiophosphoryl halides and but not thiophosphoryl iodide, . Thiophosphoryl bromide is of use in organic synthesis for reducing sulfoxides to thioethers, and sulfines to thioketones.
References
Thiophosphoryl compounds | Thiophosphoryl bromide | [
"Chemistry"
] | 316 | [
"Functional groups",
"Thiophosphoryl compounds"
] |
72,142,668 | https://en.wikipedia.org/wiki/AES50 | AES50 is an Audio over Ethernet protocol for multichannel digital audio. It is defined in the AES50-2011 standard for High-resolution multi-channel audio interconnection (HRMAI).
Origins
AES50 is based on the SuperMAC protocol created by Sony Pro Audio Lab (now Oxford Digital). The preliminary standard was assigned the AES-X140 project designation in 2003, and was finally approved in 2005 as a royalty-free open standard.
HyperMAC is an improved protocol based on Gigabit Ethernet physical layer, allowing more channels and lower audio latency. It was considered for an alternate physical layer in a future revision of AES50, but standardisation did not move forward.
Sony licensed its proprietary software implementations of SuperMAC and HyperMAC to Midas Consoles for their Midas XL8 digital mixer. Midas parent Klark Teknik took over the SuperMAC and HyperMAC patents in 2007, then in 2009 Midas and Klark Teknik were acquired by Uli Behringer's Music Group.
The AES50 protocol is implemented in digital mixing consoles by Midas and Behringer to transfer digital audio between a console and remote stage boxes.
Specifications
AES50 is a point-to-point interconnect which carries multiple channels of AES3, PCM or DSD bitstream formats, along with system clock and synchronisation signals, over Cat 5 cable using 100 Mbit/s Fast Ethernet physical layer.
AES50 uses the four pairs of the Cat 5 cable in the 8P8C connector:
Audio data transmit +
Audio data transmit –
Audio data receive +
Sync signal transmit +
Sync signal transmit –
Audio data receive –
Sync signal receive +
Sync signal receive –
Audio data is transmitted in bidirectional full-duplex mode over two differential pairs used by the 100BASE-TX standard, and word clock sync signal is transmitted over the remaining differential pairs not used by the Fast Ethernet layer. Using separate copper pairs for clock signal simplifies connection setup and allows phase-accurate low-jitter clock sync.
AES50 only employs the Ethernet protocol's physical layer (layer 1), relying on Ethernet frames to continuously stream audio data. A proprietary link layer (layer 2) implements a point-to-point audio transmission protocol. It uses a cyclic redundancy check (CRC) for each Ethernet frame and a Hamming code scheme can recover from individual bit errors. The audio data is interleaved so that neighbouring bits belong to different samples, allowing the receiving end to correct burst errors. Specialised cross-point routers can convert multiple point-to-point AES50 links to a centralised star topology.
The AES50 protocol supports 24-bit PCM audio and delta-sigma bistream formats (Direct Stream Digital), with sample rates that are a multiple of 44.1 or 48 kHz. The bandwidth of 100 Mbit/s allows 48 channels at 48 kHz sample rate, or 24 channels at 96 kHz sample rate. The latency is 6 samples at 96 kHz and 3 samples at 48 kHz, or 62.50 μs. In practical implementations of the SuperMAC and HyperMAC protocols, only 96 kHz PCM formats are supported.
AES50 also supports packet-based auxiliary channel for control data over the same data link. The control channel is allocated a fixed bandwidth of 5 Mbit/s; control data are embedded in the same Ethernet frame as the audio data.
HyperMAC
The HyperMAC protocol is based on the Gigabit Ethernet physical layer for Cat 5e cable (up to 100 m) or OM2 multi-mode fibre (up to 500 m) with embedded clocking. It allows up to 192 bidirectional channels at 96 kHz and 384 channels at 48 kHz; the latency is 4 samples at 96 kHz or 2 samples at 48 kHz, or 41.66 μs. The bandwidth of the auxiliary data link is increased to 200 Mbit/s and control data is transmitted with separate control frames.
Implementations
Midas Heritage D HD96-24 digital mixer
Midas PRO Series digital mixers
Midas M32 digital mixer
Midas XL8 digital mixer
Midas DL Series digital stage boxes
Midas DL4xx Series Audio System Signal Router
Midas Neutron Audio System Signal Router
Behringer X32 digital mixer
Behringer WING digital mixer
Behringer S Series digital stage boxes
Klark Teknik DN9620 AES50 Extender
Klark Teknik DN9630 USB Interface
Klark Teknik DN9650 Network bridge
References
External links
Audio network protocols
Networking standards
Audio engineering
Audio Engineering Society standards | AES50 | [
"Technology",
"Engineering"
] | 963 | [
"Computer standards",
"Computer networks engineering",
"Audio Engineering Society standards",
"Networking standards",
"Electrical engineering",
"Audio engineering"
] |
72,143,031 | https://en.wikipedia.org/wiki/Out-of-the-loop%20performance%20problem | The out-of-the-loop performance problem (OOL or OOTL) arises when an operator suffers from performance decrement as a consequence of automation. The potential loss of skills and of situation awareness caused by vigilance and complacency problems might make operators of automated systems unable to operate manually in case of system failure. Highly automated systems reduce the operator to monitoring role, which diminishes the chances for the operator to understand the system. It is related to mind wandering.
Etymology
OOL is also known as out-of-the-loop syndrome and out-of-the-loop effect. One of the first mentions of the term "out of the loop" is found in a patent by Willard Meilander from Goodyear Aerospace Corporation for automated aircraft control in 1972. More early mentions of OOL came up in the context of flight automation in 1980s.
Consequences
Three Mile Island accident in 1979, USAir Flight 5050 crash in 1989, Air France Flight 447 in 2009 and the loss of $400 million by Knight Capital Group in 2012 are attributed to OOL.
Automatic train operation
Automatic train operation is meant to reduce manual operation. This results in OOL performance problem for train drivers.
See also
Automation bias
References
Impact of automation
Cognitive ergonomics | Out-of-the-loop performance problem | [
"Engineering"
] | 260 | [
"Impact of automation",
"Automation"
] |
72,144,055 | https://en.wikipedia.org/wiki/Hipparchus%20star%20catalog | The Hipparchus star catalog is a list of at least 850 stars that also contained coordinates of stellar positions in the sky, based on celestial equatorial latitude and longitude. According to British classicist Thomas Heath, Hipparchus was the first to employ such a method to map the stars, at least in the West. Hipparchus is also credited with creating a celestial globe, although this object is not known to be extant. The catalog was lost to history, until parts of it were rediscovered in 2022 in the Codex Climaci Rescriptus, an ancient palimpsest found in Saint Catherine's Monastery on Mount Sinai.
Rediscovery
Contrary to Ptolemy's later star catalogue, which has survived in the Almagest and the Handy Tables, there was little evidence of the material presence, and content of the star catalog of Hipparchus. The Commentary on the Phaenomena, his sole surviving work, discusses earlier works on positional astronomy by Eudoxus of Cnidus and Aratus of Soli. Only a few references by authors after Hipparchus reflect stellar coordinates; these are mostly found in the work of Aratus.
During a multispectral image survey of the ancient Greek palimpsest known as the Codex Climaci Rescriptus in 2012, Jamie Klair, then an undergraduate student at Cambridge University, noticed that some of the folios' undertext had an astronomical nature. The folios of the Codex had been erased by the ninth or tenth century, and were reused to write Syriac translations of texts by John Climacus, a sixth century Chrisitan monk. Researchers believe that other palimpsests in Saint Catherine's Monastery of the Mount Sinai, where the Codex Climaci Rescriptus was found, may contain more fragments of the star catalog.
In 2021, Peter Williams made the first observation of the existence of astronomical measurements. Folios 47–54 and 64 of the palimpsest were originally part of an old codex that contained Aratus' Phaenomena and related writings, which were dated to the fifth or sixth century CE based on palaeographic evidence.
Modern references
Hipparchus is referenced in the name and acronym of the European Space Agency' scientific satellite "Hipparcos" (for HIgh Precision PARallax COllecting Satellite). The satellite that was launched in August 1989; it successfully monitored the celestial sphere for 3.5 years before it stopped operating in March 1993. The "Hipparcos Catalogue", which contains 118,218 stars with the maximum level of precision documented, was created using calculations from observations by the primary instrument.
References
Citations
Sources
Ancient astronomy
Stellar astronomy
Astronomical catalogues of stars
Astronomical catalogues | Hipparchus star catalog | [
"Astronomy"
] | 553 | [
"Stellar astronomy",
"History of astronomy",
"Works about astronomy",
"Astronomical catalogues",
"Astronomical objects",
"Astronomical sub-disciplines",
"Ancient astronomy"
] |
72,144,425 | https://en.wikipedia.org/wiki/Thiophosphoryl%20iodide | Thiophosphoryl iodide is an inorganic compound with the formula .
Preparation
Thiophosphoryl iodide can be prepared by reacting phosphorus triiodide with sulfur in carbon disulfide at 10–15 °C in the dark for several days.
Attempts to synthesise by the reaction of lithium iodide with thiophosphoryl bromide lead to the mixed thiophosphoryl halides and instead.
References
Thiophosphoryl compounds
Thiohalides
Inorganic phosphorus compounds | Thiophosphoryl iodide | [
"Chemistry"
] | 114 | [
"Inorganic compounds",
"Functional groups",
"Inorganic compound stubs",
"Inorganic phosphorus compounds",
"Thiophosphoryl compounds"
] |
72,145,070 | https://en.wikipedia.org/wiki/New%20York%20City%20%28painting%29 | New York City is a 1942 oil-on-canvas painting by Piet Mondrian, completed in 1942. It is on display in the Musée National d'Art Moderne at the Centre Pompidou in Paris, France.
An unfinished version of the work, titled New York City I, has strips of painted paper tape, which the artist could rearrange at will to experiment with different designs. It is exhibited at Kunstsammlung Nordrhein-Westfalen in Düsseldorf, Germany. In 2022, it was discovered that the artwork had been hanging upside down for years. To avoid damaging the painting, its orientation was not corrected.
New York City I
The Guardian states that the painting was first exhibited at the Museum of Modern Art (MoMA) in New York City in 1945, while the Netherlands Institute for Art History has no record of an exhibition at MoMA, and states that it was first exhibited at the Valentine Gallery in New York City in 1946 for about three weeks. The painting was owned by the estate of Piet Mondrian in New York City until it was transferred to the city's Sidney Janis Gallery in 1958. It was then briefly in the hands of Galerie Beyeler in Basel, Switzerland, in 1980 before being acquired by Kunstsammlung Nordrhein-Westfalen later that same year.
Art historian Susanne Meyer-Büser announced in October 2022 that the artwork had been displayed upside down at the Kunstsammlung Nordrhein-Westfalen for decades. The finished New York City has a denser group of lines at the top of the painting, which were said to represent the sky, while New York City I was displayed with those lines at the bottom. A picture of the painting in the artist's studio also showed the painting oriented with the denser lines at the top. It was conjectured that the lack of a signature on the canvas contributed to the confusion. Mondrian had not signed the work, possibly because it was unfinished.
After the issue was pointed out, a number of curators stated that the error was obvious. The museum decided to keep the painting oriented upside down, due to the fragile state of the work. It was feared that righting the artwork would cause parts of it to disintegrate, as the adhesive used had deteriorated and some of the tapes were "hanging by a thread".
Notes
References
1942 paintings
Modern paintings
Paintings by Piet Mondrian
Rotation
Paintings in the Musée National d'Art Moderne | New York City (painting) | [
"Physics"
] | 514 | [
"Physical phenomena",
"Motion (physics)",
"Classical mechanics",
"Rotation"
] |
72,146,137 | https://en.wikipedia.org/wiki/Ducks%3A%20Two%20Years%20in%20the%20Oil%20Sands | Ducks: Two Years in the Oil Sands is an autobiographical comic by Canadian cartoonist Kate Beaton. Published by Drawn & Quarterly in 2022, Ducks is an extension of a five-part webcomic Beaton initially posted to Tumblr in 2014. It is an account of her experience as a woman from Atlantic Canada working in the Athabasca oil sands in Alberta in order to pay off her student loans. The book is named after a disaster in which hundreds of ducks died after landing in a toxic tailings pond.
Summary
Ducks is a memoir of Beaton's experiences working in the oil fields in Alberta starting in 2005. Raised in Mabou, Nova Scotia, and fresh out of Mount Allison University in New Brunswick, she needs to work in order to pay off her student debt. Like many in Atlantic Canada, she is forced to seek work elsewhere; whereas previous generations would travel to work in fisheries, coal mines, or auto manufacturing plants, the mid-2000s oil boom led many Easterners to work in the oil industry. She initially works in a tool crib at Mildred Lake for Syncrude but also works at Long Lake and in various other camps taking on different roles. She meets other migrant workers, many interprovincial migrants from Eastern Canada.
Though Beaton empathizes with many of the workers and their economic plight, the labour force is overwhelmingly male, and she is subjected to sexual harassment and finds little sympathy. Fed up with her experience, she leaves to work in Victoria, British Columbia, where she begins cartooning and creates Hark! A Vagrant. Faced with low job security and unable to pay off her loans, she returns to the oil fields. She grapples with the morality of the oil industry, reflecting on harassment and sexual violence, environmental degradation, homesickness, loneliness, the health risks to workers and locals, and the destruction of the lands of the First Nations. After earning enough to pay off her loans, she leaves Alberta.
Reception and themes
Ducks has been positively received for its use of the graphic novel medium, its nuanced portrayal of life in the oil sands, and its exploration of themes such as social class, capitalism, environmentalism, and sexual harassment. Ducks is drawn in monochrome grey, and unlike Beaton's previous works, its tone is melancholic. A
New Yorker review by Sam Thielman praised her drawing, calling her use of space "exceptionally skillful" in understanding how much or how little detail to give to readers. Winnipeg Free Press reviewer Nyala Ali cited Beaton's attention to scale as a way to portray smallness and vulnerability amid the grandeur of the aurora borealis or the enormity of the vast industrial works of the oil sands and vehicles such as haul trucks. Barack Obama listed the book as one of his favourites of 2022.
Many moments in the story reflect larger movements in Canada around the environment, politics, culture, and economics surrounding the oil sands. Beaton is a migrant worker; growing up in an economically depressed part of Canada, she understood that she would have to leave home to make money and repay her student debt. She and many other workers are forced to take on difficult and undesirable jobs, and there are undertones of class resentment towards those who chastise oil sands workers while their economic standing shields them from making such a difficult compromise. Most of the other workers are men, outnumbering women 50-to-1. Beaton is subjected to frequent sexual harassment, but because of her need to pay off her debt, she does not report others and continues to work.
Writing for The Guardian, Rachel Cooke wrote that Ducks "may be the best book I have ever read about sexual harassment" and called it "abidingly humane". Despite being often gawked at and facing sexist comments and escalating unwanted sexual attention, Beaton maintains sympathy for many of the men who work with her who suffer from the loneliness, physical exhaustion and illness, and homesickness that come with their itinerant work. The harassment is persistent to the point that men try to enter her room, and it is a severe drain on her physical and mental state. When a journalist asks her about it, she becomes protective of the men, believing they have been broken by the environment and culture in which they have been immersed. The book portrays a dangerous type of masculinity that appears in the context of men who are bored, isolated, in a liminal space, provided with plentiful alcohol and cocaine, and in a physically and environmentally destructive industry; Beaton wonders if, given the same circumstances, the men in her own life would turn the same, and if anyone could emerge from the oil sands unchanged.
The environment is a consistent theme in the memoir. Etelka Lehoczky of NPR draws a parallel in the story between the harassment Beaton faces and the industrial degradation of the land. She cites a conversation with a taxi driver who takes Beaton to a site with many temporary workers and states, "You be careful, young girl. You live here, they don't. Do you know how people treat a place where they don't live?" Though Beaton considers the oil sands a temporary place to live, she realizes that the industry is displacing people of the nearby First Nations and destroying their land and drinking water. She grapples with the morality of working there knowing the damage it has wrought, but ultimately needs to repay her debts.
The book won the 2023 edition of Canada Reads, where it was championed by Mattea Roach.
Awards
Eisner Award, Best Graphic Memoir (2023) and Best Writer/Artist (2023)
Canada Reads, 2023 Winner
Harvey Award, Book of the Year (2023)
Jan Michalski Prize for Literature (2024)
References
External links
Publisher's website
2022 graphic novels
Autobiographical graphic novels
Autobiographical webcomics
Canadian graphic novels
Drawn & Quarterly titles
Environmental books
Books about Alberta
Books about petroleum
Works about internal migrations
Graphic novels set in Canada
Graphic novels set in the 2000s | Ducks: Two Years in the Oil Sands | [
"Chemistry"
] | 1,244 | [
"Chemical engineering books",
"Books about petroleum"
] |
72,147,712 | https://en.wikipedia.org/wiki/Porsche%20V4%20engine | The Porsche V4 engine is a two-liter, four-stroke, mono-turbocharged, V-4, racing engine, designed, developed, and built by German manufacturer Porsche, for their 919 Hybrid sports car prototype, between 2014 and 2017.
Background
The compact and lightweight engine was a 90-degree V4 cylinder bank mid-mounted mono-turbocharged petrol engine. It ran at 9,000 rpm, with performance coming from a direct fuel-injection system and a single Garrett-designed turbocharger with a dual overhead camshaft. It produced approximately and acted as a chassis load-bearing member. Due to the small size of the engine, the transmission casing was fitted to the rear suspension and was almost a third of the car's length. Engine air ingestion was achieved through a carbon-fiber-and-gold thermal wrapped airbox in its center. Front airflow was enabled by louvers along its flank, and a single curved roll-hoop intake was mounted on its roof to feed the carbon-fiber airbox.
Applications
Porsche 919 Hybrid
References
Porsche
Engines by model
Gasoline engines by model
Porsche in motorsport
V4 engines | Porsche V4 engine | [
"Technology"
] | 235 | [
"Engines",
"Engines by model"
] |
72,147,813 | https://en.wikipedia.org/wiki/Cyclic%20glycine-proline | Cyclic glycine-proline (cGP) is a small neuroactive peptide that belongs to a group of bioactive 2,5-diketopiperazines (2,5-DKPs) and is also known as cyclo-glycine-proline. cGP is a neutral, stable naturally occurring compound and is endogenous to the human body; found in human plasma, breast milk and cerebrospinal fluid. DKPs are bioactive compounds often found in foods. Cyclic dipeptides such as 2,5 DKPs are formed by the cyclisation of two amino acids of linear peptides produced in heated or fermented foods. The bioactivity of cGP is a property of functional foods and presents in several matrices of foods including blackcurrants.
cGP is metabolite of hormone insulin-like growth factor-1 (IGF-1). It has a cyclic structure, lipophilic nature, and is enzymatically stable which makes its a more favorable candidate for manipulating the binding-release process between IGF-1 and its binding protein thereby, normalizing IGF-1 function.
IGF-1 family
Insulin-like growth factor-1 (IGF-1) is a hormone that is structurally very similar to insulin and mediates the effects of growth hormone (GH) thus affecting metabolism, regeneration, and overall development. The GH-IGF-1 signaling pathway is crucial in the process of vascular remodeling and angiogenesis, i.e., the process of building new blood vessels and thus, helps in maintaining blood circulation in the body. In the brain, IGF-1 is abundant in various cells and regions and research over the years, suggest an imperative role of IGF-1 activity in neurodevelopment making it critical in learning and memory.
The IGF-1 family comprises
IGF-1,
IGF receptors (IGF-1R) and
IGF binding proteins (IGFBP).
The therapeutic applications of IGF-1 are limited due to its poor central uptake and potential side-effects. IGF-1 that is not bound to its binding protein bares a very short half-life and is cleaved by enzymes to form the tripeptide glycine-proline-glutamate (GPE). However, the enzymatic instability of GPE, with a plasma half-life of less than 4 minutes, is further cleaved to produce the final product, cyclic-Glycine-Proline (cGP).
Biological Role of cGP
The hepatic production of IGF-1 is controlled by the growth hormone (GH)-IGF-1 axis. The majority of circulating IGF-1 is not bioavailable because of its affinity and binding to IGF-binding protein (IGFBP), mainly IGFBP3. IGF-1 bioactivity is therefore, tightly regulated through reversible binding with IGFBP3. It is this binding-release process that determines the amount of bioavailable IGF-1 in circulation. IGF-1 that is not bound, is cleaved into an N-terminal tripeptide, Glycine-Proline-Glutamate (GPE) and Des-N-IGF-1. and GPE metabolizes to result in cyclic glycine proline (cGP).
Unbound IGF-1, cleaved at the N-terminal, can be metabolized through a series of
downstream enzymatic reactions to cGP. The N-terminal is the binding site of IGF-1 which allows cGP to retain the same binding affinity to IGFBP-3 and thus, regulates the bioavailability of IGF-1 through competitive binding with IGFBP3. An increase in cGP, would increase competitive advantage and thus, increase the amount of circulating and therefore, bioavailable IGF-1.
Research shows that cGP can normalize IGF-1 function under pathophysiological conditions of increased or diminished IGF-1 bioactivity.
In vitro studies show that cGP promoted the activity of IGF-1 when insufficient and inhibited the activity of IGF-1 when in excess.
Uses
A recently published review in the journal Marine Drugs, provides an excellent overview of cGP sources and biological effects. Biologically, cGP is most strongly associated with cognitive benefits, however it also has a role in other biological functions, as outlined below.
Cognition
Vascular health is critical in maintaining cognitive function. IGF-1 plays an essential role in vascular remodelling of the brain and supports cognitive retention. Metabolic IGF-1 levels tend to reduce with age and this reduction appears to be a major contributor to cognitive impairment in older populations.
Low or deficient IGF-1 levels can be normalized by cGP, restoring its vascular function. Studies evaluating cGP, IGF-1 and IGFBP3 levels suggest that cGP concentration and cGP/IGF-1 molar ratio were positively associated suggesting that older people with higher plasma cGP concentration (and cGP/IGF-1 molar ratio) have better memory/cognitive retention.
Hypertension
IGF-1 plays a critical role in energy metabolism with deficient IGF-1 levels being implicated in obesity and hypertension.
Stroke
The role of IGF-1 in supporting recovery from stroke, which is a condition of vascular origin, is reported. A study in 34 stroke patients reported that patients with higher plasma concentration of cGP made better recovery within 3 months than those with lower cGP levels. Further, patients with higher cGP levels also showed lesser neurological deficits.
Therapeutic Potential
Excessive IGF-1 activity promotes tumorigenesis while reduced IGF-1 activity is linked with diseases such as Alzheimer's and Parkinson's. cGP normalises the autocrine function of IGF-1 under pathological conditions and when there are low levels of cGP in the human body, IGF-1 regulation is compromised. Therefore, it is reasonable to assume that treatment with exogenous cGP could assist with improving IGF-1 implicated health benefits.
References
Neuropeptides
Diketopiperazines
Heterocyclic compounds with 2 rings | Cyclic glycine-proline | [
"Chemistry"
] | 1,328 | [
"Ketones",
"Functional groups"
] |
72,148,537 | https://en.wikipedia.org/wiki/Carbonea%20aggregantula | Carbonea aggregantula is a species of lichenicolous (lichen-dwelling) fungus belonging to the family Lecanoraceae.
It is a lichenicolous fungus, meaning that it grows on other lichens, but it does not cause obvious symptoms of infection, unlike the similar Carbonea austroshetlandica.
Distribution
Carbonea aggregantula is widely distributed. Although it has not been reported often, its distribution includes multiple continents. Carbonea aggregantula has been reported from some of the subantarctic islands, including King George Island, Penguin Island and Livingston Island.
Host species
Carbonea aggregantula has a wide range of host species which are still being discovered. Known hosts are:
Candelariella sp.
Lecanora alpigena
Lecanora impudens
Lecanora leproplaca
Lecanora leucococca
Lecanora polytropa
Lecanora subaurea
Lecanora subgranulata
Protoparmeliopsis muralis
Rhizoplaca aspidophora (synonym of Lecanora aspidophora)
References
Lecanoraceae
Fungus species
Fungi described in 1874
Fungi of Antarctica
Lichenicolous fungi
Taxa named by Johannes Müller Argoviensis | Carbonea aggregantula | [
"Biology"
] | 260 | [
"Fungi",
"Fungus species"
] |
72,149,189 | https://en.wikipedia.org/wiki/Richmann%27s%20law | Richmann's law, sometimes referred to as Richmann's rule, Richmann's mixing rule, Richmann's rule of mixture or Richmann's law of mixture, is a physical law for calculating the mixing temperature when pooling multiple bodies. It is named after the Baltic German physicist Georg Wilhelm Richmann, who published the relationship in 1750, establishing the first general equation for calorimetric calculations.
Origin
Through experimental measurements, Wilhelm Richmann determined that the following relationship holds when water of different temperatures is mixed:
It follows:
Here and are the masses of the two mixture components, and are their respective initial temperatures, and is the mixture temperature.
This observation is called Richmann's law in the narrower sense and applies in principle to all substances of the same state of aggregation. According to this, the mixing temperature is the weighted arithmetic mean of the temperatures of the two initial components.
Richmann's rule of mixing can also be applied in reverse, for example, to the question of the ratio in which quantities of water of given temperatures must be mixed to obtain water of a desired temperature. Determining the quantities and required for this purpose, given a total quantity , is accomplished with the mixing cross. The corresponding formula, obtained from the above equation by rearrangement, is:
or .
For the mixing ratio, this gives:
.
The physical background of the mixing rule is the fact that the heat energy of a substance is directly proportional to its mass and its absolute temperature. The proportionality factor is the specific heat capacity, which depends on the nature of the substance, but which was not described until some time after Richmann's discovery by Joseph Black. Thus, the validity of the formula is limited to mixtures of the same substance, since it assumes a uniform specific heat capacity. Another condition is that both components be uniformly warm everywhere and that there be no appreciable heat exchange with their other surroundings.
If one wants to mix two substances with different - but known - specific heat capacities, one can formulate the mixing rule more generally, as shown below.
General formulation
Under the condition that no change of aggregate state occurs and the system is closed, i.e., in particular, there is no heat exchange with the environment, the following holds:
Where and represent the specific enthalpy of the respective components.
If the specific heat capacities and can be assumed to be constant, this can be transformed to.
The formula resolved by the mixture temperature is then:
In a wider sense this equation is also referred to as Richmann's law because it simply extends Richmann's established relationship to include the specific heat capacity, thus allowing the calculation of the mixing temperature of different substances.
If the heat capacities are not constant over the entire temperature range, the above formula can be used with an average heat capacity for component :
.
In this formula, with or represents the specific heat capacity of the two components, which may be temperature dependent. Application of the formula may require an iterative procedure to determine the mixture temperature, since the average heat capacity is also temperature dependent.
References
Scientific laws
Calorimetry | Richmann's law | [
"Mathematics"
] | 630 | [
"Mathematical objects",
"Scientific laws",
"Equations"
] |
72,150,315 | https://en.wikipedia.org/wiki/List%20of%20electric%20truck%20makers | This is a list of electric truck makers that have produced medium- and heavy-duty commercial battery-powered all-electric trucks.
Multiple-brand corporations
The following truck brands are owned by Big Three automobile manufacturers and other corporations which hold multiple automobile and truck brands.
Hyundai-Kia
In 2020, Hyundai sold over 9,000 units of its Porter Electric truck in South Korea while Kia sold over 5,000 units of the Kia Bongo EV in the same market.
Mercedes-Benz Group
Mercedes-Benz
Mercedes-Benz began delivering eActros units to 10 customers in September 2018 for a two-year real-world test. Customers include Dachser, Edeka, Hermes, Kraftverkehr Nagel, Ludwig Meyer, Pfenning Logistics, TBS Rhein-Neckar and Rigterink of Deutschland, and Camion Transport and Migros of Switzerland. In 2023, the eActros 600 with a 621 kWh battery and a range of 500 km was presented, with production starting in 2024.
Daimler AG
Freightliner
Freightliner began delivering e-M2 trucks to Penske in December 2018, and will commercialize its larger e-Cascadia in 2019. Since 2023 Daimler offers MT50e electric step-van with the exact cargo capacity and dimensions as its diesel counterpart. The 2024 model offers level 2 home charging which was absent on the 2023 model.
Mitsubishi Fuso
Mitsubishi Fuso began deliveries of the eCanter in 2017.
Rizon
Daimler launched the all-electric truck Rizon brand in the United States in 2023. Journalists questioned whether the Rizon trucks are rebranded Mitsubishi Fuso eCanter trucks, but Daimler did not address these questions.
Paccar
DAF
DAF delivered its first CF semi-truck to Jumbo for testing in December 2018. It uses a VDL powertrain. The logistics company Tinie Manders Transport received a unit in February 2019, and Contargo in Germany received two units in May.
Peterbilt
Peterbilt unveiled in early 2018 a partnership with Meritor and TransPower, who will supply all-electric drivetrain systems for two Peterbilt vehicle platforms. They will produce twelve Class 8 579EV day cab tractors and three 520EV trash trucks that will be tested for about a year. In January 2019, Peterbilt unveiled its medium-duty 220EV also made in partnership with Meritor and TransPower. Six units should be delivered to its major customer in 2019. The manufacturer expects to have a total of more than 30 electric trucks on the road by the end of 2019.
Tata
Tata Ultra T.7 is India's first fully electric truck. The truck comes with mordern design and powertrain of zero emission.It is designed to bear a payload range of 3692–4935 kg.
It has a weight of 7490 kg and equipped with 6 wheels. Tata motors also launched an electric version of Tata Ace. It is a small commercial vehicle which is designed to be used in cities. The Ace EV is the first product featuring Tata Motors' EVOGEN powertrain. It is powered by a 27 kW (36 hp) motor with 130 N m of peak torque, cargo volume of 208 ft^3 and grade-ability of 22%.
Toyota
Hino
Hino Motors partnered with SEA Electric to provide Hino electric trucks using the SEA-Drive powertrain. The trucks are scheduled to become available in 2024 in the United States. SEA Electric has been installing its electric powertrains in medium and heavy-duty trucks and buses since 2017.
Volkswagen AG
MAN
MAN began delivering a dozen units of various e-TGM trucks in September 2018 for testing purposes with different customers. Serial production was scheduled to begin in 2022.
Volvo AB
Mack
Mack unveiled the LR refuse truck in May 2019. Its commercialization should begin in 2019. New York City Department of Sanitation will test one unit beginning in 2020.
Renault Trucks
Renault Trucks, part of Volvo, began selling an electric version of its Maxity small truck in 2010. Renault Trucks was the first to build heavy-duty trucks, with three prototypes of electric Renault Midlum and a later Renault D tested in real conditions by different customers (Carrefour, Nestlé, Guerlain) for a few years between 2012 and 2016. A prototype D truck was delivered to Delanchy in November 2017.
After testing is completed, Renault will commercialize its D and D Wide trucks in 2019. They will be built in France alongside their Volvo counterparts.
Renault Trucks has unveiled the models of its heavy-duty all-electric range in November 2022. The Renault Trucks E-Tech T and C, which are for regional distribution and construction, will be produced in series at the Bourg-en-Bresse factory from 2023.
Volvo
Volvo planned to launch their first mass-produced electric FE and FL trucks in early 2021, to be built in France alongside their Renault counterparts. An electric VNR semi-trailer truck was delivered to North American customers for testing in 2021. An updated VNR Electric is scheduled to begin production in 2022, in Dublin, Virginia.
Single-brand corporations
Alkè
Some of the electric cars made by Alkè (for example the Alkè ATX 100 E) are used in soccer stadiums as open ambulances. The operator of London's cycle hire scheme uses a small number of Alkè electric utility vehicles (alongside other cars and vans) to tow trailers for distributing bicycles.
Autocar trucks
Autocar's E-ACTT is the fully-electric version of its leading ACTT terminal tractor model. Andrew Taitz, chairman of Autocar said, "The E-ACTT is the only original equipment manufacturer (OEM) terminal tractor with an OEM developed electric vehicle system, all Autocar".
Autocar announced two alpha units of the E-ACX low cabover model began field testing in August 2022.
BYD
In China, BYD sold 7,969 all-electric/PHEV/hydrogen commercial vehicles in 2018, and 3,836 of them in 2019. These figures exclude buses.
The manufacturer sells light-, medium- and heavy-duty electric trucks. The heaviest of them is the 8TT, which is a Class 8 semi-tractor equipped with a 435 kWh battery. The Chinese manufacturer gained a foothold in the US market: its customers include Anheuser-Busch, which deployed 21 electric semi-tractors from BYD in California.
E-Force One
In January 2014, COOP Switzerland began operating an 18-ton (16 metric ton) electric truck with a replaceable battery. 18 square meters of photovoltaic elements are positioned on its roof. The truck's battery has a capacity of 300 kWh. The solar panels along with regenerative braking provide 23 percent of the total energy. The range is 240 km per day. Energy consumption is 130 kWh per 100 km. Net of the solar/regenerative energy it consumes about 100 kWh per 100 km, about the energy needed by a comparable diesel engine. The truck weighs eight tons, with a gross vehicle weight of 18 tonnes and costs 380,000 Swiss francs. It is about twice as expensive as the diesel version. The truck is based on an Iveco Stralis chassis. The truck's operating price is 10 francs per 100 kilometres, much less than the diesel version at 50 francs per 100 kilometres. The truck has two LiFePO4 batteries with a capacity of 120 kWh with a weight of 1300 kg. The battery can be replaced within 10 minutes. Maintenance and the service life are not higher than a comparable diesel truck.
Two trucks began operating in mid-2014 at Lidl in Switzerland and one at Feldschlösschen Beverages Ltd. In June 2015, Pistor began operating one. Shipping company Meyer Logistics uses refrigerated models in Berlin.
EVage Motors
EVage Motors is an Indian electric vehicle manufacturer focusing on the commercial electric vehicle sector. The company aims to enhance last-mile delivery solutions through its electric vehicles. EVage's flagship product, is a last-mile delivery van, the FR8.
GGT Electric
In 2011, GGT Electric, an automotive engineering, design and manufacturing company based in Milford, Michigan, introduced a new line of all-electric trucks for sale. GGT has developed LSV zero-emission electric vehicles for fleet markets, municipalities, universities, and state and federal government. The company offers 4-door electric pick-up trucks, electric passenger vans, and flatbed electric trucks with tilt and dump capability.
Haul truck
The company Lithium Storage GmbH is building together with the company Kuhn Switzerland AG a battery-powered haul truck. The vehicle is to go the end of 2016 in operation. The dump truck weighs 110 tons. The chassis is a Komatsu 605–7. The vehicles have an electric motor with 800 hp and can thus produce 5900 Nm. The battery is a 600 kWh lithium-ion battery. For comparison, diesel vehicles of this type consume approximately 50,000 to 100,000 liters of diesel per year.
Motiv Power Systems
Beginning in 2015 Motiv's delivery trucks have been in service with AmeriPride in linen delivery applications. Motiv electrified chassis were certified by the California Air Resources Board, enabling them to be sold through California state programs including HVIP. Motiv collaborates with existing truck body manufacturers to allow them to sell electric options using the electrified chassis as a drop in replacement on their existing manufacturing lines. An example of this type of manufacturing can be seen in the development of delivery vans with both Morgan Olson and Utilimaster.
Nikola Motors
Nikola Motors produces a battery-electric variant of their Nikola Tre truck.
As of July, 2024 Nikola motor has produced more than 225 BEV & FCEV class 8 trucks. And currently 200+ Class 8 Trucks are on the roads in California and Canada.
Orange EV
Riverside, Missouri-based Orange EV began producing Class-8 all-electric terminal trucks for industrial use in 2012. It operates in 35 states in America and is the manufacturer in the country with the most zero emission trucks in operation. The company uses a turnkey approach that enables its clients to get end-to-end support. In June 2022, the 3rd generation 4x2 e-TRIEVER truck was announced.
Its e-TRIEVER truck has a gross vehicle weight rating of 81,000 lb, a max speed of 25 mph, maximum lift height of 62 inches, and battery capacity of 100 or 180 kWh.
After delivering over 950 Pure Electric Yard Dogs to the North American Market, In 2023, Orange EV introduced a second model, the HUSK-e. Designed to work in Port and Rail operations, it is capable of pulling up to 180k lb GCVW up to 32 mph and has a 243 kWh LFP battery pack.
PMP
PMP, an electric vehicle design, manufacturing and engineering company based in Saskatchewan, Canada introduced a full line of electric heavy-duty underground mining trucks ranging from utility vehicles to 12-passenger personnel transport vehicle.
Rivian
Rivian has produced Rivian EDV since 2019. The original batch of vehicles were produced for Amazon.
Smith Electric Vehicles
Launched in 2006, the Newton electric truck is an all-electric commercial vehicle from Smith Electric Vehicles. The Newton comes in three GVW configurations: , and . Each is available in short, medium or long wheelbase.
The truck was launched with a 120 kilowatt electric induction motor from Enova Systems, driven by Lithium-Ion Iron Phosphate batteries supplied by Valence Technology. In 2012 Smith re-released the Newton with new driveline and battery systems that were developed in-house. Smith offers the battery pack in either 80 kWh or 120 kWh configurations.
, the Newton is sold worldwide and available with three different payload capacities from . The lithium-ion battery pack is available in varying sizes that deliver a range from and a top speed of .
Terberg
The Dutch manufacturer, Terberg, has provided an electrically powered 40-ton truck for transporting material on public roads; it is reported to commute eight times a day between a logistics center and the Munich BMW plant. The truck battery takes three to four hours to charge. When fully charged, the vehicle has a range of up to 100 kilometres. Thus, the electric truck can theoretically complete a full production day without any additional recharging. Compared to a diesel engine truck, the electric truck will save 11.8 tons of CO2 annually.
Tesla
Tevva
In September 2021, Tevva unveiled its Tevva Truck – the first British designed 7.5-tonne electric truck intended for mass production in the UK. The truck has a range of up to 160 miles (250 km) in pure battery electric vehicle (BEV) form or up to 310 miles (500 km) with its patented range extender technology (REX). The Tevva Truck can carry up to 16 euro pallets and over two tonnes payload at 7.5-tonnes Gross Vehicle Weight (GVW). The total cost of ownership is comparable to a diesel; parity is achieved at approximately 3,000 km or when 500 litres of diesel is consumed per month.
VinFast
At the 2024 Consumer Electronics Show, VinFast introduced their first all-electric mid-size pickup truck VF Wild with length of 209 inches (5324 mm) and a width of 79 inches (1997 mm).
Volta
The company has developed a truck that gives the driver a 220-degree view, similar to what one might see on a city bus. The driver's seat is in the centre of the cab. On the inside of the 16-ton truck, called Volta Zero, sits a single unit containing an electric motor, transmission and rear axle supplied by OEM supplier Meritor. The truck has a range of between 150 and 200 km per charge.
Workhorse
Workhorse manufactures the Workhorse W56.
Xos
Xos, Inc. manufactures and sells Class 5, 6, 7, and 8 commercial and heavy-duty battery electric trucks for "last-mile" and "back-to-base" routes.
See also
List of electric bus makers
Electric van
Electric vehicle conversion
References
Makers and models
Electrical-engineering-related lists
Truck-related lists
Lists of manufacturers | List of electric truck makers | [
"Engineering"
] | 2,913 | [
"Electrical engineering",
"Electrical-engineering-related lists"
] |
72,150,362 | https://en.wikipedia.org/wiki/Z-Cote | Z-Cote is a commercial zinc oxide line manufactured and owned by BASF. Due to Z-Cote's photo-protective properties it is commonly used in personal care products and sunscreens. It is available in nano, non-nano, coated and uncoated forms. Z-Cote is a derivative of zinc oxide which is Generally Recognized As Safe and Effective (GRASE) by the FDA as a nutrient, cosmetic colour additive, skin protection active ingredient and other OTC products. Manufactured zinc oxide, such as Z-Cote, is only recognised as GRASE by the FDA when it is compliant with the Good manufacturing practice (GMP) standard. The original Sunsmart and Submicro Encapsulation Technologies Z-Cote patent filed in 1991 for UV skin protection expired in 2015.
History
Z-Cote was acquired from SunSmart in 1999 by BASF. It has been used in sunscreen formulations since at least 1993 in microfine form. The initial 1991 Z-Cote patent placed emphasis on broad-spectrum protection, especially UVA. Only in 1993 did the FDA approve an alternative petrochemical sunscreen ingredient, avobenzone, that also provided protection against UVA.
Environmental impact
Plants
Z-Cote was studied to evaluate hypothetical agricultural impacts if it were to contaminate irrigated water. In the study it was found that Z-Cote had a negligible impact on bean (Phaseolus vulgaris) pod production and increased root length and the concentration of more nutritional elements.
Reef
Zinc oxide is compliant with Hawaii Act 104 banning non-reef safe petrochemicals.
Zinc oxide producers
Croda International
BASF
Umicore
References
Cosmetics
Zinc oxide
Sunscreening agents
Natural products | Z-Cote | [
"Chemistry"
] | 348 | [
"Natural products",
"Medicinal chemistry"
] |
72,150,632 | https://en.wikipedia.org/wiki/HD%2043899 | HD 43899, also designated as HR 2263, is a solitary, orange hued star located in the southern constellation Columba, the dove. It has an apparent magnitude of 5.53, allowing it to be faintly visible to the naked eye. Based on parallax measurements from the Gaia spacecraft, the object is estimated to be 284 light years distant. It appears to be rapidly receding with a heliocentric radial velocity of . Eggen (1993) lists HD 43899 as an old disk star and its kinematics match with that of the ζ Herculis moving group.
HD 43899 is an evolved giant star that is currently on the horizontal branch, a red clump star, fusing a hydrogen shell around an inert helium core. It has a stellar classification of K2 III. At present the object has 115% the mass of the Sun and an effective temperature of . At the age of 6.32 billion years, it has already left the main sequence and now radiates 61 times the luminosity of the Sun from an enlarged photosphere 12.4 times that of the sun. HD 43899 has an iron abundance 24% below solar levels, making it slightly metal deficient. It spins modestly with a projected rotational velocity of .
References
K-type giants
Columba (constellation)
Columbae, 86
043899
CD-37 02707
029842
2263
Zeta Herculis Moving Group | HD 43899 | [
"Astronomy"
] | 309 | [
"Columba (constellation)",
"Constellations"
] |
72,151,584 | https://en.wikipedia.org/wiki/Pierre-Marie%20Touboulic | Pierre-Marie Touboulic (17 June 1783, Brest, France - 8 June 1859 Paris) was a naval engineer, inventor and writer.
Biography
Pierre-Marie Touboulic was born in Brest on 17 June 1783. He was the fifth of six children of master locksmith Jean-Louis Touboulic and Marie Félicité Abalain. His first wife was Hortense Auvray, married on 17 June 1818 in Brest, with whom he had a daughter Hortense Félicité Claudine , born 26 April 1819. He married a second time to Jeanne Augustine Le Donné on 16 May 1825, and a third time to Marie Guillemette Querné on 13 January 1836, both also in Brest.
He was the brother of Toussaint Touboulic, knight of the Order of Saint Louis, and captain of a frigate. The son of one of his cousins, Perrine Jeanne Adélaïde Touboulic, born 11 July 1780 in Lorient, was Louis Maurice Adolphe Linant de Bellefonds, born 23 November 1799.
He was made an Knight of the Legion of Honour in 1825, and died in Paris on 8 June 1859 at 6 rue de Castiglione in the 1st arrondissement.
Career
Touboulic spent his entire working life in Brest. Appointed marine engineer in 1818, he was head of the compass workshop from 1825 to 1836, and later mechanical engineer.
He built models of the ports of Brest, Lorient and Toulon, and a relief map of Rochefort, and invented tools used by various sectors of the navy including a variation compass in 1856 (patent of invention code 26642 at the INPI), a diving bell (departmental archives of Finistère, code 4 T 5), an aerial transport system that he called a velocipost in 1808 (patent number 1BA6239 at the INPI), the ancestor of the first urban cable car, before the railways, in 1838, which was first tested from 3 to 12 October 1838 in the Bois de Bordenave in Brest. The experiment was continued in 1839 for at least three months on the ramparts of Fort Bouguen with the participation of about 800 people. The press of the time (Armoricain) suggested possible uses for transport of convicts, the sick, etc. The Brest cable car was called the Touboulic Express by the city of Brest in 2014.
Touboulic took out a patent on a rebreather, based on the absorption of carbon dioxide on 17 June 1808. It had a tank containing oxygen which was released by the diver, and circulated in a closed circuit through a sponge soaked in lime water. Touboulic called his invention Ichtioandre (Greek for “fish-man”).
In 1834, he experimented with submarines on the Loire.
References
Bibliography
History of underwater diving
19th-century French inventors
1783 births
1859 deaths
People from Brest, France
19th-century French engineers
19th-century French writers
19th-century French male writers
Marine engineers | Pierre-Marie Touboulic | [
"Engineering"
] | 621 | [
"Marine engineers",
"Marine engineering"
] |
72,151,787 | https://en.wikipedia.org/wiki/Paleobiota%20of%20the%20Burgess%20Shale | This is a list of the biota of the Burgess Shale, a Cambrian lagerstätte located in Yoho National Park in Canada.
The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At 508 million years old (middle Cambrian), it is one of the earliest fossil beds containing soft-part imprints. During the Cambrian, the ecosystem of the Burgess Shale sat under 100 to 300 metres (330 to 1000 feet) of water at the base of a submarine canyon known as the Cathedral Escarpment, which today is a part of the Canadian Rockies. The ecosystem would have sat in dimly lit water, most likely at the edge, or in the Mesopelagic zone. The ecosystem was preserved by rapid mudslides that quickly buried organisms near, or on the seafloor, which helps explain the rarity of nektonic organisms at the site. The shale would have supported unique environments like brine pools that could have also helped to preserve the fossils. Notable areas that expose the Burgess Shale include the Walcott Quarry, Marble Canyon, Stephen Formation, Tulip beds, Stanley Glacier, the Trilobite Beds and the Cathedral Formation. With each site occupying a varying depth, and distance from the base of the escarpments.
Arthropoda
Crown-group arthropods (euarthropods such as trilobites) and their stem-group relatives (such as radiodonts) are extremely diverse and some species are abundant in the Burgess Shale. Along with their earlier-diverging cousins, the "Lobopodians", they provide great information on early Panarthropod evolution.
Lobopodians
Lobopodians, a grouping of worm-like panarthropods from which arthropods arose, were present in the shale.
Sponges
Sponges (Porifera) were extremely diverse in the shale, with many of them belonging to the class Demospongiae.
Comb-jellies (Ctenophora)
Crown-group and stem-group Ctenophores, also known as comb jellies, are moderately common in the shale, with five genera known from the site.
Hemichordata
Many of the Hemichordates from the shale have either remained enigmatic, or were once classified under other groupings.
Annelida
A number of different Annelid worms are known from the shale.
Priapulida
Various stem-group priapulids are known from the Burgess Shale.
Mollusca
The molluscs of the Burgess shale are diverse in body shapes, the ecological niches they filled, and their enigmatic qualities.
Brachiopods
Many of the brachiopods from the site are members of the class Lingulata.
Cnidaria
A wide variety of cnidarians like scyphozoans and conulariids are known from this site.
Echinodermata
The echinoderms of the shale represent extinct groups distantly related to extant groups.
Chordata
Chordates are very rare in the shale, but the two that are known are possibly being very important in the study of these creatures earlier evolution.
Gnathifera
A number of different gnathiferans, including chaetognaths (arrow worms) and other groups are known from the Burgess Shale.
Chancellorids
An extinct group of enigmatic sponge-like animals covered in hollow spines
Cyanobacteria
Cyanobacteria are photosynthesizers, and would have been important in the shale.
Red algae (Rhodophyta)
Red algae are found in the shale, with three genera being known.
Incertae sedis and miscellaneous
This section documents organisms from the shale whose taxonomic affinities are not fully understood, or that do not fit into any of the above groups.
References
Burgess Shale
Burgess Shale fossils
Paleozoic paleobiotas | Paleobiota of the Burgess Shale | [
"Biology"
] | 806 | [
"Paleozoic paleobiotas",
"Prehistoric biotas"
] |
72,152,592 | https://en.wikipedia.org/wiki/Polygamy%20in%20Africa | Polygamy in Africa has existed throughout the history of Africa. Polygamy, particularly polygyny, is a highly valued social institution in Africa. Polygamy is a marriage between a man or woman and their multiple spouses. Polygyny is a marriage between a man and multiple wives. Polyandry is a marriage between a woman and multiple husbands. A common expectation for African kings in African societies is for African kings to symbolically unify his kingdom and the society through partaking in polygamous marriages with wives from a broad range of clans within the society. By doing so, the king reduces the chance of dissident and rival forces developing and rising against him.
History
North Africa
Egypt
Evidence for polygamy in ancient Egypt can be found among both the Middle Kingdom and New Kingdom.
During the dynastic rule of Amenophis III, numerous polygynous marriages between Amenophis III and foreign princesses occurred, which later led to the princesses being buried in the Valley of the Queens along with the following description of them as part of the harem of the king: “'She of numerous nights in the city of the brilliant Aten'; 'She who appears in glory in the temple of the brilliant Aten'; 'She who strikes with fury for the brilliant Aten'.”
An example of polygamy from a 20th Dynasty period papyrus, which is one among several other examples from the 20th Dynasty that highlight grave robberies, highlights the tribunal case of gold worker, Ramose; during the case, Mutemhab, his wife, indicated during her testimony that he had two dead wives and another wife who was not dead; notably, Ramose was subsequently brought to trial for grave robbery and not polygamy.
While Herodotus characterized the ancient Egyptians as being monogamous, Diodorus characterized the ancient Egyptians as being polygamous; according to Diodorus Siculus, "In accordance with the marriage-customs of the Egyptians the priests have but one wife, but any other man takes as many as he may determine; and the Egyptians are required to raise all their children in order to increase the population, on the ground that large numbers are the greatest factor in increasing the prosperity of both country and cities."
West Africa
Ivory Coast
Following the development of Ivory Coast’s first national census in 1975 CE, 23% of men were found to be participating in a polygynous marriage in 1988 CE, and the average polygynist man was found to have 2.3 wives, with higher rates of polygyny found in rural areas than in Abidjan. From 1955 CE to 1988 CE, rates of polygyny in Ivory Coast remained fairly consistent, occurring with four out of 10 married women, though there was some decline found in rural areas from the early 1960s CE to mid-1970s CE.
Mali
Between the 12th century CE and the 15th century CE, polygamy was a cultural practice of the Mali Empire. In the Mande narrative of Sundiata Keita’s Epic, Keita partook in a polygamous marriage with two women, whom he had children with, and whose children were in political competition with one another.
Mauritania
In Tichitt culture, households may have been used by extended families or polygamous families at locations such as Akreijit.
East Africa
Uganda
During the Kingdom of Buganda, the king of Buganda partook in polygynous marriages to reduce the chance of dissident and rival forces developing and rising against him.
Customs
North Africa
Egypt
While monogamy was predominant among ancient Egyptians, neither customs and traditions nor laws of ancient Egypt criminalize polygamy. A husband treating his wife well, family stability, and wholesome co-parenting was encouraged. The act of adultery was socially stigmatized. Women could also compose their own marital contracts, which may have contributed to lower rates of divorce and opportunities for polygyny.
Kings of ancient Egypt partook in polygynous marriages. Politically arranged polygynous marriages occurred between male members of the royal family and foreign princesses. While lower class and middle class men mostly could not afford to financially support more than two wives or wife and concubine(s), kings and upper class men could afford to engage in polygamy, with kings having many wives and concubines and upper class men having at least one wife and some concubines.
It can be difficult to draw broad conclusions about the ancient Egyptians and polygamy due to the frequent ambiguity found among available evidence from ancient Egypt. For example, a 20th Dynasty period papyrus includes the following common example found among available evidence: “‘The citizeness A, the wife of B, and the citizeness C, his other wife, in total 2.’” As Watterson (2011) states regarding this common example: “The reference may be to two contemporaneous wives; on the other hand, wife A may have been divorced or dead before B married wife C – there is nothing to indicate which was the real state of affairs.”
Less ambiguous evidence for polygamy in ancient Egypt can be found among both the Middle Kingdom and New Kingdom. Examples from the Middle Kingdom involve people from among the bureaucrat class of ancient Egypt. An example from a papyrus, which is one among several other examples from the 20th Dynasty that highlight grave robberies, highlights the tribunal case of gold worker, Ramose; during the case, Mutemhab, his wife, indicated during her testimony that he had two dead wives and another wife who was not dead; notably, Ramose was subsequently brought to trial for grave robbery and not polygamy. During the dynastic rule of Amenophis III, numerous polygynous marriages between Amenophis III and foreign princesses occurred, which later led to the princesses being buried in the Valley of the Queens along with the following description of them as part of the harem of the king: “'She of numerous nights in the city of the brilliant Aten'; 'She who appears in glory in the temple of the brilliant Aten'; 'She who strikes with fury for the brilliant Aten'.”
While Herodotus characterized the ancient Egyptians as being monogamous, Diodorus characterized the ancient Egyptians as being polygamous; according to Diodorus Siculus, "In accordance with the marriage-customs of the Egyptians the priests have but one wife, but any other man takes as many as he may determine; and the Egyptians are required to raise all their children in order to increase the population, on the ground that large numbers are the greatest factor in increasing the prosperity of both country and cities."
West Africa
Ivory Coast
Following the development of Ivory Coast’s first national census in 1975 CE, 23% of men were found to be participating in a polygynous marriage in 1988 CE, and the average polygynist man was found to have 2.3 wives, with higher rates of polygyny found in rural areas than in Abidjan. From 1955 CE to 1988 CE, rates of polygyny in Ivory Coast remained fairly consistent, occurring with four out of 10 married women, though there was some decline found in rural areas from the early 1960s CE to mid-1970s CE.
Mali
Between the 12th century CE and the 15th century CE, polygamy was a cultural practice of the Mali Empire. In the Mande narrative of Sundiata Keita’s Epic, Keita partook in a polygamous marriage with two women, whom he had children with, and whose children were in political competition with one another.
Mauritania
In Tichitt culture, households may have been used by extended families or polygamous families at locations such as Akreijit.
East Africa
Uganda
During the Kingdom of Buganda, the king of Buganda partook in polygynous marriages to reduce the chance of dissident and rival forces developing and rising against him.
References
Polygamy by continent
Culture of Africa
Polygamy
Mating systems | Polygamy in Africa | [
"Biology"
] | 1,641 | [
"Behavior",
"Mating systems",
"Mating"
] |
72,152,623 | https://en.wikipedia.org/wiki/Handy%20Tables | Ptolemy's Handy Tables () is a collection of astronomical tables that second century astronomer Ptolemy created after finishing the Almagest. The Handy Tables elaborated the astronomical tables of the Almagest and included usage instructions, but left out the theoretical commentary in order to facilitate practical computation. The work is considered of high significance during the late antiquity and in the Middle Eastern and Eastern Mediterranean medieval traditions.
References
Bibliography
Ancient astronomy
Stellar astronomy | Handy Tables | [
"Astronomy"
] | 86 | [
"Ancient astronomy",
"History of astronomy",
"Astronomy stubs",
"Stellar astronomy stubs",
"Astronomical sub-disciplines",
"Stellar astronomy"
] |
72,152,899 | https://en.wikipedia.org/wiki/WR%20119 | WR 119 is a Wolf–Rayet star located about 10,500 light years away in the constellation Scutum. WR 119 is classified as a WC9 star, belonging to the late-type carbon sequence of Wolf-Rayet stars. WR 119 is noteworthy for being the least luminous known Wolf-Rayet star, at just over . The most recent estimate is even lower, at just , based on the most recent analysis using Gaia DR2 data.
Properties
WR 119's properties are on the very edge of what may be possible for Wolf-Rayet stars, due to being so extremely dim. Modelling its spectrum using PoWR gives a temperature of . Factoring in the distance used in that study of , WR 119's luminosity is only , derived from Gaia DR2's parallax data. The corresponding radius is only , the smallest of the WC9 stars, less than half the size of the average WC9 star. WR 119's luminosity is also just 20% that of the average WC9 star's luminosity. The corresponding mass is just , the lowest mass for any Wolf-Rayet star derived using a mass-luminosity relation.
In the visual wavelength, the star is also the dimmest of the WC9 stars (and anything later than WC4 in the study), with a visual luminosity of just 3,130 L☉ because most of the is emitted at ultraviolet wavelengths due to WR 119's very high surface temperature.
WR 119 has a strong stellar wind, typical of Wolf-Rayet stars, but weaker than most WC stars. WR 119 loses 10-5.13 M☉ (about ) per year because of this stellar wind, which has a terminal velocity of 1,300 kilometres per second. WR 119 also emits a lot of dust, hence the "d" at the end of its spectral type, which may be an indication of binary status.
References
Wolf–Rayet stars
Scutum (constellation) | WR 119 | [
"Astronomy"
] | 411 | [
"Scutum (constellation)",
"Constellations"
] |
72,152,911 | https://en.wikipedia.org/wiki/Biofabrication | Biofabrication is a branch of biotechnology specialising in the research and development of biologically engineered processes for the automated production of biologically functional products through bioprinting or bioassembly and subsequent tissue maturation processes; as well as techniques such as directed assembly, which employs localised external stimuli guide the fabrication process; enzymatic assembly, which utilises selective biocatalysts to build macromolecular structures; and self-assembly, in which the biological material guides its own assembly according to its internal information. These processes may facilitate fabrication at the micro- and nanoscales. Biofabricated products are constructed and structurally organised with a range of biological materials including bioactive molecules, biomaterials, living cells, cell aggregates such as micro-tissues and micro-organs on chips, and hybrid cell-material constructs.
See also
References
Works cited
Biological engineering
Biotechnology | Biofabrication | [
"Engineering",
"Biology"
] | 183 | [
"Biological engineering",
"Bioengineering stubs",
"Biotechnology stubs",
"Biotechnology",
"nan"
] |
59,829,183 | https://en.wikipedia.org/wiki/Hazel%20Reeves | Hazel Reeves, MRSS SWA is a British sculptor based in Sussex, England, who specialises in figure and portrait commissions in bronze. Her work has been shown widely across England and Wales. Public commissions can be found in Carlisle, London, Congleton and Manchester. Since 2021, Reeves' work increasingly embraces soundscapes of nature and movement.
Early life and education
Reeves was born in Croydon, Surrey and now lives in Brighton, East Sussex. She attended Imberhorne School in East Grinstead, West Sussex, Kingston Business School and the London School of Economics and Political Science (LSE) to study international development and gender equality MSc (Econ). In 2003 she studied sculpture with Sylvia MacRae Brown at the University of Sussex, at Heatherley School of Fine Art (London) and in 2009 at the Florence Academy of Art, Italy.
Career
Reeves' first quasi-public commission was of Sadako Sasaki for the Hedd Wen Peace Place, Llanfoist, Abergavenny, unveiled on the World Day of Peace, 21 September 2012. It tells the story of Sadako and her 1000 paper cranes, used worldwide in peace education.
The statue of Sir Nigel Gresley, designer of steam locomotives Flying Scotsman and Mallard, was Reeves' first major public commission. Her original design had included a mallard duck but it was removed after objections from two relatives who thought it was demeaning. The statue was unveiled at London King's Cross railway station on 6 April 2016, the 75th anniversary of his death.
On International Women's Day, 8 March 2018, Reeves' Cracker Packers statue was unveiled in Caldewgate, Carlisle, close to the pladis factory, where Carr's Table Water Biscuits are manufactured. The statue celebrates the lives of women biscuit factory workers from the Carr's factory in Carlisle. Based on former and current Cracker Packers the statue is of two women factory workers, one from the past and one from the present, standing atop a giant Carr's Table Water Biscuit. The statue was commissioned by Carlisle City Council and was one of hundreds that were nominated for Historic England's "Immortalised" season in 2018.
In 2017, Reeves' winning design – Rise up, Women – was selected from a shortlist of six designs for a bronze statue of Emmeline Pankhurst, by winning the public vote and being the unanimous choice of the WoManchester Statue Project selection panel. The statue of Emmeline Pankhurst was unveiled in St Peter's Square, Manchester (her hometown) on 14 December 2018. In 2021 it won the Public Statues and Sculpture Association (PSSA) Marsh Award for Excellence in Public Sculpture.
Reeves' statue of Elizabeth Wolstenholme Elmy (1833-1918), a pioneering activist who fought for equality throughout her life, was unveiled in Congleton by Baroness Hale of Richmond on International Women's Day, 8 March 2022.
Reeves seeks to redress the lack of representation of women in some of her public commissions as well as private commissions, such as portrait sculptures of disability rights activists Baroness Jane Campbell and Diane Kingston. Reeves has been appointed to sculpt Ada Nield Chew (1870-1945), the vocal factory worker who became a women's rights campaigner, for installation in Crewe. The 'Statue for Ada' campaign is coordinated by Cheshire Women's Collaboration.
Sir John Manduell CBE, the Founding Principal who brought together two Manchester music schools to establish the Royal Northern College of Music (RNCM), will be honoured June 2024 with a new bust created by Hazel Reeves.
Reeves was artist-in-residence in 2021 at Knepp Estate, West Sussex, recording bird soundscapes to inspire movement. Her resultant Sculptural Murmurings project at Fabrica Gallery, Brighton, was funded by the National Lottery through Arts Council England, who are also funding Reeves' Soundscapes of Hope project in 2022/23, drawing on her field recordings at Knepp and the nature reserves of Svartådalan, Sweden. Two sound events resulted in 2023: Layback with Nature (Phoenix Art Space, Brighton) and Sculptural Murmurings (II) (Fabrica Gallery).
In 2024, Reeves' collaborated with pianist and composer Damian Montagu on the track Knepp Dawn, released on 5 May 2024 to mark International Dawn Chorus Day. The track celebrates the dawn chorus in the Knepp scrubland that features bird species facing cataclysmic declines elsewhere, like the nightingale, turtle dove, cuckoo, white stork.
Reeves was elected to the Society of Women Artists (SWA) in 2009 and elected a member of the Royal Society of Sculptors (MRSS) in 2017. She teaches portrait sculpture workshops at Art Junction in Billingshurst, Phoenix Brighton, Morley College (London) and Masterclasses at the Art Academy (London).
References
External links
Knepp Wildland Podcast - The Soundscape, with Hazel Reeves, Episode 24
Living people
Year of birth missing (living people)
21st-century English sculptors
21st-century English women artists
Alumni of Kingston University
Alumni of the London School of Economics
Alumni of the University of Sussex
Artists from Brighton
English women sculptors
Artists from London
People from Croydon
21st-century British women sculptors
Sound artists
Field recording | Hazel Reeves | [
"Engineering"
] | 1,085 | [
"Audio engineering",
"Field recording"
] |
59,829,761 | https://en.wikipedia.org/wiki/Higman%E2%80%93Sims%20asymptotic%20formula | In finite group theory, the Higman–Sims asymptotic formula gives an asymptotic estimate on number of groups of prime power order.
Statement
Let be a (fixed) prime number. Define as the number of isomorphism classes of groups of order . Then:
Here, the big-O notation is with respect to , not with respect to (the constant under the big-O notation may depend on ).
References
Group theory
Theorems in group theory | Higman–Sims asymptotic formula | [
"Mathematics"
] | 96 | [
"Group theory",
"Fields of abstract algebra"
] |
59,831,317 | https://en.wikipedia.org/wiki/Caitr%C3%ADona%20Lally | Caitríona Lally is a professor of Bioengineering in Trinity College, Dublin. She has been a qualified mechanical engineer since 1997. She did a PhD in cardiovascular biomechanics.
Education
Lally studied mechanical engineering in the University of Limerick, achieving a first-class honours degree (1993 – 1997). She earned a Master’s of Bioengineering and Biomechanical Engineering at the University of Limerick (1997 – 1999). Lally got her PhD from Trinity College Dublin, in arterial biomechanics and cardiovascular stenting, linked with Medtronic (2000 – 2004); she wrote her thesis and did her research under Patrick Prendergast, the then Professor of Biomechanical Engineering.
In her third year in UL, she spent 9 months on work placement in Stryker, which is one of the largest orthopaedic implant companies in the world. It was on this placement where she realised that she could apply her mechanical engineering to medicine and biology.
Career
After completing her PhD, she became a lecturer in Biomedical Engineering in the Dublin City University (DCU). She worked as a lecturer in biomedical engineering for over 10 years (March 2004 – October 2014), before becoming a senior lecturer in Biomedical Engineering in DCU. Lally became a Professor in Bioengineering at Trinity College Dublin where she lectures and conducts research (2015 – Present).
She has continued her research from her time in DCU and she is working with the Centre for Advanced Medical Imaging in St. James’s Hospital. Lally is the lead investigator on a project, focusing on developing a means of early diagnosis of degenerative cardiovascular diseases.
Research
Lally has published over 50 papers, receiving over 1800 citations. Her research focuses on arterial tissue mechanics, vascular imaging, vascular mechanobiology and tissue engineering.
In 2014, she secured an ERC (European Research Council) starting grant for a five-year €1.5m project that will advance research in arterial fibre remodelling for vascular disease diagnosis and tissue engineering.
Publications
Her publications include:
In Vitro Corrosion and Biological Assessment of Bioabsorbable WE43 Mg Alloy Specimens.
A strain-mediated corrosion model for bioabsorbable metallic stents.
Fibre orientation of fresh and frozen porcine aorta determined non-invasively using diffusion tensor imaging.
Personal life and activism
Lally features in the group portrait at the Women on Walls campaign by Accenture with the Royal Irish Academy. Lally also features on Silicon Republic’s list of ‘25 of Ireland’s phenomenal women of engineering’.
Awards and honors
2004: Royal Society of Medicine in Ireland, 1st prize student paper
2005: Career Start Grant (DCU)
2012: IMECHE Young Engineers Research Award
References
Year of birth missing (living people)
Living people
Bioengineers
Irish mechanical engineers
Biomechanics
Alumni of Trinity College Dublin
Alumni of the University of Limerick
Academics of Trinity College Dublin
Academics of Dublin City University | Caitríona Lally | [
"Engineering",
"Biology"
] | 606 | [
"Bioengineers",
"Biological engineering"
] |
59,833,359 | https://en.wikipedia.org/wiki/Pixel%20Visual%20Core | The Pixel Visual Core (PVC) is a series of ARM-based system in package (SiP) image processors designed by Google. The PVC is a fully programmable image, vision and AI multi-core domain-specific architecture (DSA) for mobile devices and in future for IoT.
It first appeared in the Google Pixel 2 and 2 XL which were introduced on October 19, 2017. It has also appeared in the Google Pixel 3 and 3 XL. Starting with the Pixel 4, this chip was replaced with the Pixel Neural Core.
History
Google previously used Qualcomm Snapdragon's CPU, GPU, IPU, and DSP to handle its image processing for their Google Nexus and Google Pixel devices. With the increasing importance of computational photography techniques, Google developed the Pixel Visual Core (PVC). Google claims the PVC uses less power than using CPU and GPU while still being fully programmable, unlike their tensor processing unit (TPU) application-specific integrated circuit (ASIC).
Indeed, classical mobile devices equip an image signal processor (ISP) that is a fixed functionality image processing pipeline. In contrast to this, the PVC has a flexible programmable functionality, not limited only to image processing.
The PVC in the Google Pixel 2 and 2 XL is labeled SR3HX X726C502.
The PVC in the Google Pixel 3 and 3 XL is labeled SR3HX X739F030.
Thanks to the PVC, the Pixel 2 and Pixel 3 obtained a mobile DxOMark of 98 and 101.
The latter one was the top-ranked single-lens mobile DxOMark score, tied with the iPhone XR.
Pixel Visual Core software
A typical image-processing program of the PVC is written in Halide. Currently, it supports just a subset of Halide programming language without floating point operations and with limited memory access patterns.
Halide is a domain-specific language that lets the user decouple the algorithm and the scheduling of its execution.
In this way, the developer can write a program that is optimized for the target hardware architecture.
Pixel Visual Core ISA
The PVC has two types of instruction set architecture (ISA), a virtual and a physical one. First, a high-level language program is compiled into a virtual ISA (vISA), inspired by RISC-V ISA, which abstracts completely from the target hardware generation. Then, the vISA program is compiled into the so-called physical ISA (pISA), that is a VLIW ISA. This compilation step takes into account the target hardware parameters (e.g. array of PEs size, STP size, etc...) and specify explicitly memory movements. The decoupling of vISA and pISA lets the first one to be cross-architecture and generation-independent, while pISA can be compiled offline or through JIT compilation.
Pixel Visual Core architecture
The Pixel Visual Core is designed to be a scalable multi-core energy-efficient architecture, ranging from even numbers between 2 and 16 core designs. The core of a PVC is the image processing unit (IPU) a programmable unit tailored for image processing. The Pixel Visual Core architecture was also designed either to be its own chip, like the SR3HX, or as an IP block for System on a chip (SOC).
Image Processing Unit (IPU)
The IPU core has a stencil processor (STP), a line buffer pool (LBP) and a NoC.
The STP mainly provides a 2-D SIMD array of processing elements (PEs) able to perform stencil computations, a small neighborhood of pixels. Though it seems similar to systolic array and wavefront computations, the STP has an explicit software controlled data movement. Each PEs features 2x 16-bit arithmetic logic units (ALUs), 1x 16-bit Multiplier–accumulator unit (MAC), 10x 16-bit registers, and 10x 1-bit predicate registers.
Line Buffer Pool (LBP)
Considering that one of the most energy costly operation is DRAM access, each STP has temporary buffers to increase data locality, namely LBP. The used LBP is a 2-D FIFO that accommodates different sizes of reading and writing. The LBP uses single-producer multi-consumer behavioral model. Each LBP can have eight logical LB memories and one for DMA input-output operations.
Due to the real high complexity of the memory system, the PVC designers state the LBP controller as one of the most challenging components.
The NoC used is a ring network on chip used to communicate with only neighbor cores for energy savings and pipelined computational pattern preservation.
Stencil Processor (STP)
The STP has a 2-D array of PEs: for example, a 16x16 array of full PEs and four lanes of simplified PEs called "halo".
The STP has a scalar processor, called scalar lane (SCL), that adds control instructions with a small instruction memory.
The last component of an STP is a load store unit called sheet generator (SHG), where the sheet is the PVC memory access unit.
SR3HX design summary
The SR3HX PVC features a 64-bit ARMv8a ARM Cortex-A53 CPU, 8x image processing unit (IPU) cores, 512 MB LPDDR4, MIPI, PCIe.
The IPU cores each have 512 arithmetic logic units (ALUs) consisting of 256 processing elements (PEs) arranged as a 16 x 16 2-dimensional array. Those cores execute a custom VLIW ISA.
There are two 16-bit ALUs per processing element and they can operate in three distinct ways: independent, joined, and fused.
The SR3HX PVC is manufactured as a SiP by TSMC using their 28HPM HKMG process.
It was designed over 4 years in partnership with Intel. (Codename: Monette Hill) Google claims the SR3HX PVC is 7-16x more energy-efficient than the Snapdragon 835. And that the SR3HX PVC can perform 3 trillion operations per second, HDR+ can run 5x faster and at less than one-tenth the energy than the Snapdragon 835.
It supports Halide for image processing and TensorFlow for machine learning. The current chip runs at 426 MHz and the single IPU is able to perform more than 1 TeraOPS.
References
Google hardware
Application-specific integrated circuits | Pixel Visual Core | [
"Technology",
"Engineering"
] | 1,369 | [
"Application-specific integrated circuits",
"Computer engineering"
] |
59,833,659 | https://en.wikipedia.org/wiki/Gapped%20Hamiltonian | In many-body physics, most commonly within condensed-matter physics, a gapped Hamiltonian is a Hamiltonian for an infinitely large many-body system where there is a finite energy gap separating the (possibly degenerate) ground space from the first excited states. A Hamiltonian that is not gapped is called gapless.
The property of being gapped or gapless is formally defined through a sequence of Hamiltonians on finite lattices in the thermodynamic limit.
An example is the BCS Hamiltonian in the theory of superconductivity.
In quantum many-body systems, ground states of gapped Hamiltonians have exponential decay of correlations.
In quantum field theory, a continuum limit of many-body physics, a gapped Hamiltonian induces a mass gap.
References
Quantum mechanics | Gapped Hamiltonian | [
"Physics"
] | 167 | [
"Theoretical physics",
"Quantum mechanics",
"Quantum physics stubs"
] |
59,835,979 | https://en.wikipedia.org/wiki/AZ%20Phoenicis | AZ Phoenicis (HR 239) is a variable star in the constellation of Phoenix. It has an average visual apparent magnitude of 6.47, so it is at the limit of naked eye visibility. From parallax measurements by the Gaia spacecraft, it is located at a distance of from Earth. Its absolute magnitude is calculated at 1.65.
AZ Phoenicis is a Delta Scuti variable that pulsates with a single period of 79.3 minutes, causing its visual brightness to vary with an amplitude of 0.015 magnitudes. Its variability was discovered by Werner Weiss in 1977, from observations with the 50-cm telescope at La Silla Observatory. AZ Phoenicis has also been classified as a possible Ap star, which remains uncertain, even though the star has a large concentration of metals; the overall metallicity of the star has been measured to about 3 times the solar metallicity.
This star is classified with a spectral type of A9/F0III, corresponding to a giant of type A or F. With an estimated radius of 2.7 times the solar radius, it is shining with 19 times the solar luminosity at an effective temperature of 7,280 K. The astrometric observations by the Hipparcos spacecraft detected a significant acceleration in the proper motion of AZ Phoenicis, indicating it is an astrometric binary.
References
Delta Scuti variables
Phoenix (constellation)
A-type giants
F-type giants
Astrometric binaries
Durchmusterung objects
004849
003903
0239
Phoenicis, AZ | AZ Phoenicis | [
"Astronomy"
] | 325 | [
"Phoenix (constellation)",
"Constellations"
] |
59,836,267 | https://en.wikipedia.org/wiki/PG%283%2C2%29 | In finite geometry, PG(3, 2) is the smallest three-dimensional projective space. It can be thought of as an extension of the Fano plane.
It has 15 points, 35 lines, and 15 planes. It also has the following properties:
Each point is contained in 7 lines and 7 planes.
Each line is contained in 3 planes and contains 3 points.
Each plane contains 7 points and 7 lines.
Each plane is isomorphic to the Fano plane.
Every pair of distinct planes intersects in a line.
A line and a plane not containing the line intersect in exactly one point.
Constructions
Construction from K6
Take a complete graph K6. It has 15 edges, 15 perfect matchings and 20 triangles. Create a point for each of the 15 edges, and a line for each of the 20 triangles and 15 matchings. The incidence structure between each triangle or matching (line) and its three constituent edges (points) induces a .
Construction from Fano planes
Take a Fano plane and apply all 5040 permutations of its 7 points. Discard duplicate planes to obtain a set of 30 distinct Fano planes. Pick any of the 30, and pick the 14 others that have exactly one line in common with the first, not 0 or 3. The incidence structure between the Fano planes and the 35 triplets they mutually cover induces a .
Representations
Tetrahedral depiction
can be represented as a tetrahedron. The 15 points correspond to the 4 vertices + 6 edge-midpoints + 4 face-centers + 1 body-center. The 35 lines correspond to the 6 edges + 12 face-medians + 4 face-incircles + 4 altitudes from a face to the opposite vertex + 3 lines connecting the midpoints of opposite edges + 6 ellipses connecting each edge midpoint with its two non-neighboring face centers. The 15 planes consist of the 4 faces + the 6 "medial" planes connecting each edge to the midpoint of the opposite edge + 4 "cones" connecting each vertex to the incircle of the opposite face + one "sphere" with the 6 edge centers and the body center. This was described by Burkard Polster. The tetrahedral depiction has the same structure as the visual representation of the multiplication table for the sedenions.
Square representation
can be represented as a square. The 15 points are assigned 4-bit binary coordinates from 0001 to 1111, augmented with a point labeled 0000, and arranged in a 4×4 grid. Lines correspond to the equivalence classes of sets of four vertices that XOR together to 0000. With certain arrangements of the vertices in the 4×4 grid, such as the "natural" row-major ordering or the Karnaugh map ordering, the lines form symmetric sub-structures like rows, columns, transversals, or rectangles, as seen in the figure. (There are 20160 such orderings, as seen below in the section on Automorphisms.) This representation is possible because geometrically the 35 lines are represented as a bijection with the 35 ways to partition a 4×4 affine space into 4 parallel planes of 4 cells each. This was described by Steven H. Cullinane.
Doily depiction
The Doily diagram often used to represent the generalized quadrangle is also used to represent . This was described by Richard Doily.
Kirkman's schoolgirl problem
arises as a background in some solutions of Kirkman's schoolgirl problem. Two of the seven non-isomorphic solutions to this problem can be embedded as structures in the Fano 3-space. In particular, a spread of is a partition of points into disjoint lines, and corresponds to the arrangement of girls (points) into disjoint rows (lines of a spread) for a single day of Kirkman's schoolgirl problem. There are 56 different spreads of 5 lines each. A packing of is a partition of the 35 lines into 7 disjoint spreads of 5 lines each, and corresponds to a solution for all seven days. There are 240 packings of , that fall into two conjugacy classes of 120 under the action of (the collineation group of the space); a correlation interchanges these two classes.
Automorphisms
The automorphism group of maps lines to lines. The number of automorphisms is given by finding the number of ways of selecting 4 points that are not coplanar; this works out to 15⋅14⋅12⋅8 = 20160 = 8!/2. It turns out that the automorphism group of is isomorphic to the alternating group on 8 elements A8.
Coordinates
It is known that a can be coordinatized with (GF(2))n+1, i.e. a bit string of length . can therefore be coordinatized with 4-bit strings.
In addition, the line joining points and can be naturally assigned Plücker coordinates where , and the line coordinates satisfy . Each line in projective 3-space thus has six coordinates, and can be represented as a point in projective 5-space; the points lie on the surface .
Notes
References
Projective geometry
Finite geometry
Incidence geometry
Sedenions
Configurations (geometry) | PG(3,2) | [
"Mathematics"
] | 1,071 | [
"Incidence geometry",
"Combinatorics"
] |
59,836,605 | https://en.wikipedia.org/wiki/Daniel%20Dumbacher | Daniel Dumbacher is an American aerospace engineer, educator and administrator. Dumbacher was appointed an executive director of American Institute of Aeronautics and Astronautics in 2017. He served as deputy associate administrator of NASA's Human Exploration and Operations Mission Directorate from 2007 to 2014. Dumbacher was a professor at Purdue University School of Aeronautics and Astronautics from 2014 to 2017.
Dumbacher earned a BS in mechanical engineering from Purdue University in 1981 and an MBA from the University of Alabama in Huntsville in 1984.
References
NASA people
Aerospace engineers
Purdue University faculty
Year of birth missing (living people)
Living people
Purdue University College of Agriculture alumni
University of Alabama in Huntsville alumni | Daniel Dumbacher | [
"Engineering"
] | 133 | [
"Aerospace engineers",
"Aerospace engineering"
] |
59,836,665 | https://en.wikipedia.org/wiki/Baade-Wesselink%20method | The Baade-Wesselink method is a method for determining the distance of a Cepheid variable star suggested by Walter Baade in 1926 and further developed by Adriaan Wesselink in 1946. In the original method the color of the star at various points during its period of variation is used to determine its surface brightness. Then, knowing the apparent magnitude at these points in time the angular diameter can be calculated. Measurements are also taken of the radial velocity using Doppler spectroscopy. This allows one to determine the speed at which the front surface of the star moves toward or away from us at various points in the cycle. Since the difference between this and the average speed is the derivative of the radius, one obtains the variation in radius. Combining this with the change in angular diameter gives the distance. It is now possible to measure the angular diameter of the pulsating star directly using optical interferometers, allowing a more accurate measurement of the star's distance. This newer technique is known as the geometric Baade–Wesselink method.
A closely related technique is the expanding photosphere method, which can be used to determine the distance to Type II supernovae.
References
Astrometry
Cepheid variables | Baade-Wesselink method | [
"Astronomy"
] | 252 | [
"Astrometry",
"Astronomical sub-disciplines"
] |
59,836,785 | https://en.wikipedia.org/wiki/Evolution%20Without%20Selection | Evolution without Selection: Form and Function by Autoevolution is a 1988 book on evolution by cytogeneticist A. Lima-de-Faria.
The book argues that only physical and chemical processes are real and the modern neo-Darwinian population genetics approach to evolution is misguided. Lima-de-Faria emphasizes that the laws of physics and chemistry generate the basic forms found in living organisms, and that physicochemical forces and organisms interact at many levels. The central premise of the book is that the current models of biological evolution such as the modern evolutionary synthesis ignore the active contribution of these forces.
Lima-de-Faria proposes an alternative to the modern evolutionary synthesis known as "autoevolutionism", a form of orthogenesis. He argues in the book that selection is not the mechanism of evolution because it cannot be weighed on a balance, poured into a vial, or measured in specific units. Only a material component can be the mechanism of evolution, and this must be found in the physico-chemical processes.
Lima-de-Faria holds that there are no random events in evolution, there is no natural selection and all living and non-living matter evolve from the same laws. Lima-de-Faria lists 56 principles of "autoevolutionism". He also gives 75 differences between autoevolution and neo-Darwinism. Lima-de-Faria wrote that "In the framework of autoevolutionism, orthogenesis appears as the direct result of the canalization inherent to the evolutions that preceded biological evolution, and as a result of the autonomous evolutions that occur within the cell and the organism."
The book also argues against sexual selection. Lima-de-Faria maintains that the bright colours in certain animals are caused by high temperatures.
Reception
The idea of autoevolutionism has been described as a "minority opinion at the fringes of official circles of thoughts and of the mainstream."
A review by multiple authors in the Origins of Life and Evolution of Biospheres journal noted:
There are a few valid points in A. Lima-de-Faria's Evolution Without Selection Form and Function by Autoevolution but unfortunately they are embedded in the far-fetched examples, illogical progressions and disjointed lists with which the author attempts to demonstrate that evolution occurs not by natural selection but by autoevolution. Lima-de-Faria's major problem with natural selection seems to be that it is not Popperian enough. The term is abstract and the concept is impossible to prove with a controlled scientific experiment; as Lima-de-Faria states it 'Selection cannot be weighed or poured into a vial. As such it is not a component of the mechanism of evolution' (pp. 7, 312). This is a good example of the type of non sequitur that is abundant in this book, in that weighability and pourability are not criteria that come to mind when evaluating theories, nor is autoevolution itself especially weighable or pourable.
Geneticist Austin L. Hughes wrote that the basic idea behind the book "seems to be that there are certain laws of form built into the universe which somehow determine the development of organisms as well as a number of abiotic processes", but the definition of autoevolution was never made clear. He criticized the book noting that "many aspects of biology are discussed in the text, but these discussions are riddled with erroneous and unsupported statements" and concluded that population biology has discredited any theory of orthogenesis.
Historian of biology Igor Popov who has written a book on the history of orthogenesis has commented that the Lima-de-Faria's treatise has "all the drawbacks of theoretical biological treatises such as bulky collections of facts, hasty generalisations, the lack of scientific argumentation and a style which is critical without being creative."
Biologist Gert Korthof has criticized Lima-de-Faria for employing outrageous criteria.
References
1988 non-fiction books
1988 in biology
Books about evolution
Elsevier books
Non-Darwinian evolution
Orthogenesis | Evolution Without Selection | [
"Biology"
] | 862 | [
"Orthogenesis",
"Non-Darwinian evolution",
"Biology theories",
"Obsolete biology theories"
] |
59,837,099 | https://en.wikipedia.org/wiki/Pseudo-panspermia | Pseudo-panspermia (sometimes called soft panspermia, molecular panspermia or quasi-panspermia) is a well-supported hypothesis for a stage in the origin of life. The theory first asserts that many of the small organic molecules used for life originated in space (for example, being incorporated in the solar nebula, from which the planets condensed). It continues that these organic molecules were distributed to planetary surfaces, where life then emerged on Earth and perhaps on other planets. Pseudo-panspermia differs from the fringe theory of panspermia, which asserts that life arrived on Earth from distant planets.
Background
Theories of the origin of life have been recorded since the 5th century BC, when the Greek philosopher Anaxagoras proposed an initial version of panspermia: life arrived on earth from the heavens. In modern times, full panspermia has little support amongst mainstream scientists. Pseudo-panspermia, in which molecules are formed and transported through space is, however, well-supported.
Extraterrestrial creation of organic molecules
Interstellar molecules are formed by chemical reactions within very sparse interstellar or circumstellar clouds of dust and gas. Usually this occurs when a molecule becomes ionised, often as the result of an interaction with cosmic rays. This positively charged molecule then draws in a nearby reactant by electrostatic attraction of the neutral molecule's electrons. Molecules can also be generated by reactions between neutral atoms and molecules, although this process is generally slower. The dust plays a critical role of shielding the molecules from the ionizing effect of ultraviolet radiation emitted by stars. The Murchison meteorite contains the organic molecules uracil and xanthine, which must therefore already have been present in the early Solar System, where they could have played a role in the origin of life.
Nitriles, key molecular precursors of the RNA World scenario, are among the most abundant chemical families in the universe and have been found in molecular clouds in the center of the Milky Way, protostars of different masses, meteorites and comets, and also in the atmosphere of Titan, the largest moon of Saturn.
Evidence for the extraterrestrial creation of organic molecules includes both their discovery in various contexts in space, and their laboratory synthesis under extraterrestrial conditions:
Planetary distribution of organic molecules
Organic molecules can then be distributed to planets including Earth both when the planets formed and later. If the materials from which planets formed contained organic molecules, and were not destroyed by heat or other processes, then these would be available for abiogenesis on those planets.
Later distribution is by means of bodies such as comets and asteroids. These may fall to the planetary surface as meteorites, releasing any molecules they are carrying as they vaporise on impact or later as they erode. Findings of organic molecules in meteorites include:
References
Astrobiology
Origin of life
Speculative evolution
Astrochemistry | Pseudo-panspermia | [
"Chemistry",
"Astronomy",
"Biology"
] | 585 | [
"Origin of life",
"Hypothetical life forms",
"Speculative evolution",
"Astrobiology",
"Astrochemistry",
"nan",
"Biological hypotheses",
"Astronomical sub-disciplines"
] |
59,837,154 | https://en.wikipedia.org/wiki/Oxford%20Concordance%20Program | The Oxford Concordance Program (OCP) was first released in 1981 and was a result of a project started
in 1978 by Oxford University Computing Services (OUCS) to create a machine independent text analysis program for producing word lists, indexes and concordances in a variety of languages and alphabets.
In the 1980s it was claimed to have been licensed to around 240 institutions in 23 countries.
History
OCP was designed and written in FORTRAN by Susan Hockey and Ian Marriott of Oxford University Computing Services in the period 1979–1980 and its authors acknowledged that it owed much to the earlier COCOA and CLOC (University of Birmingham) concordance systems.
During 1985–86 OCP was completely rewritten as version 2 to increase the efficiency of the program, a version was also produced for the IBM PC called Micro-OCP.
See also
Concordance (publishing)
References
History of software
Digital humanities | Oxford Concordance Program | [
"Technology"
] | 180 | [
"Digital humanities",
"History of software",
"Computing and society",
"History of computing"
] |
59,837,342 | https://en.wikipedia.org/wiki/Thomas%20N.%20Farris | Thomas Neal Farris is an American aerospace engineering professor and university administrator. He is known for his research on mechanics of fretting fatigue. Tom Farris was the Dean of Rutgers School of Engineering from 2009-2022. He served as the Head of Purdue University School of Aeronautics and Astronautics from 1998 to 2009.
Farris received a BS degree in mechanical engineering in 1982 from Rice University and a Ph.D. in Applied Mechanics at Northwestern University in 1986.
Farris is a Fellow of American Society of Mechanical Engineers since 2001 and a Fellow of American Institute of Aeronautics and Astronautics since 2009.
References
Living people
Year of birth missing (living people)
Rice University alumni
Northwestern University alumni
Tribologists | Thomas N. Farris | [
"Materials_science"
] | 143 | [
"Tribology",
"Tribologists"
] |
59,839,734 | https://en.wikipedia.org/wiki/FSR%201758 | FSR 1758 (also known as the Sequoia Cluster) is a large and bright but heavily obscured globular cluster belonging to the Milky Way galaxy. It is located at a distance of about 11.5 kpc from the Sun and about 3.7 kpc from the center of the galaxy. As FSR 1758 lies behind the galactic bulge, it is heavily obscured by the foreground stars and dust. It was first noticed in 2007 in 2MASS data and believed to be an open cluster, until data from the Gaia mission revealed in 2018 that it is a globular cluster.
The size and brightness of FSR 1758 may be comparable to or exceed that of the Omega Centauri cluster, which is widely believed to be the nucleus of a dwarf galaxy that merged into Milky Way in the past. Therefore, FSR 1758 may be the nucleus of dwarf galaxy tentatively named Scorpius Dwarf galaxy. It may also be similar to another globular cluster, Messier 54, which is known to be the nucleus of Sagittarius Dwarf Spheroidal Galaxy.
After Barbá et al. used the term Sequoia to describe the size of FSR 1758, Myeong et al. used the term Sequoia in a slightly different way. They believe that FSR 1758 was one of five globular clusters that populated a dwarf galaxy that Myeong et al. re-name as the Sequoia dwarf galaxy. This dwarf was accreted into the Milky Way in the Sequoia Event. The members of Sequoia have a retrograde galactic orbit. This term has been adopted by several other groups.
References
Globular clusters
Scorpius | FSR 1758 | [
"Astronomy"
] | 349 | [
"Scorpius",
"Constellations"
] |
59,840,224 | https://en.wikipedia.org/wiki/Sherine%20Obare | Sherine O. Obare is the dean of the Joint School of Nanoscience and Nanoengineering at the University of North Carolina at Greensboro and North Carolina Agricultural and Technical State University. She works on nanomaterials for sensing and drug delivery.
Early life and education
Obare spent her childhood in Germany, where she attended a British high school. She studied chemistry, mathematics and physics. She majored in engineering, but decided to focus on chemistry because of her college roommate. She eventually began her bachelor's degree in chemistry at West Virginia State University and graduated in 1998. She applied for a job at the United States Environmental Protection Agency, but was convinced by her professor to she would enjoy graduate school. She joined the University of South Carolina for her doctoral studies and earned her PhD in 2002. She worked under the supervision of Catherine J. Murphy. With Murphy, Obare developed a new approach to fabricate polystyrene and silica coated gold nanorods as templates for hollow nanotubes. Hollow nanotubes are useful for drug delivery, cell and enzyme transplantation, removal of contaminated waste and gene therapy. To create the gold nanorods, Obare used nanoparticles as a seed in a growth solution that contained cetyltrimethylammonium bromide, sodium hydroxide and ascorbic acid at a controlled pH (3.5). She demonstrated that gold nanoparticles functionalised with 1,10-phenanthroline could be used to sense lithium ions in solution. The ligands of 1,10-phenanthroline bind to the lithium ions, forming a complex that causes the nanoparticles to aggregate. Obare explored several ligands, including dipyridophenazine (DPPZ) which changes colour when it binds to lithium ions. The nanorods can form liquid crystalline phases. Obare was a Camille and Henry Dreyfus Foundation fellow at Johns Hopkins University working under the supervision of Gerald Meyer.
Career
In 2004 Obare joined Western Michigan University as an assistant professor and promoted to tenure in 2009. She also works on nanomaterials for drug delivery and chemical sensing. She investigated fluorescent chemosensors to monitor for organophosphorous. Organophosphorous can inhibit cholinesterase and can have severe environmental and health impacts. Obare was awarded an National Science Foundation CAREER Award in 2006. This allowed her to develop multi-electron transfer catalysts. Obare is interested in multi-electron transfer. She has investigated electron transfer from heme-functionalised titanium dioxide to organohalide pollutants. She demonstrated that organohalides degrade via multi-electron pathways. She has explored new techniques to synthesise and characterise monodisperse nanoparticles. The nanoparticles can be used to detect bacteria in waterborne diseases.
Obare was appointed associate dean at Western Michigan University in 2015. She was responsible for research, education, diversity and global engagement across the university. She believes that early authentic research is essential for underrepresented groups to gain rational view of the world. From 2017 Obare served as Associate Vice President for Research at Western Michigan University.
Obare is an associate editor for the Journal of Nanomaterials. She moved to the University of North Carolina at Greensboro as dean of the Joint School of Nanoscience and Nanoengineering. In October 2023, Obare was named the Vice Chancellor for Research and Engagement at University of North Carolina at Greensboro. Obare chairs the American Chemical Society Award for Incorporation of Sustainability into the Curriculum.
Awards and honours
2006 National Science Foundation CAREER Award
2007 American Chemical Society Dreyfus Lectureship Award
2009 Haenicke Institute for Global Education International Faculty Development Award
2009 International Union of Pure and Applied Chemistry Young Observer Award
2009 National Science Foundation Materials Grant
2010 American Competitiveness and Innovation (ACI) Fellowship
2010 NOBCChE Lloyd N. Ferguson Young Scientist Award
2010 Science Spectrum Magazine Trailblazer Award
2012 National Organization for the Professional Advancement of Black Chemists and Chemical Engineers President’s Award
Books
2018 The Power and Promise of Early Research
References
African-American chemists
American chemists
21st-century American chemists
American women chemists
Women physical chemists
University of Southern California alumni
West Virginia State University alumni
Western Michigan University faculty
University of North Carolina faculty
Year of birth missing (living people)
Living people
American women academics
21st-century African-American women
21st-century African-American scientists
21st-century American women scientists | Sherine Obare | [
"Chemistry"
] | 919 | [
"Women physical chemists",
"Physical chemists"
] |
59,840,522 | https://en.wikipedia.org/wiki/NGC%204065 | NGC 4065 is an elliptical galaxy located 300 million light-years away in the constellation Coma Berenices. The galaxy was discovered by astronomer William Herschel on April 27, 1785. It was then rediscovered by John Herschel on April 29, 1832 and was listed as NGC 4057. NGC 4065 is the brightest member of the NGC 4065 Group.
NGC 4065 is a companion of NGC 4061. The two galaxies form an interacting pair, as evidenced by distortions in their optical isophotes.
It is classified as a radio galaxy.
See also
List of NGC objects (4001–5000)
References
External links
4065
038156
07050
Coma Berenices
Astronomical objects discovered in 1785
Elliptical galaxies
Radio galaxies
NGC 4065 Group
Interacting galaxies
Discoveries by William Herschel | NGC 4065 | [
"Astronomy"
] | 162 | [
"Coma Berenices",
"Constellations"
] |
67,735,743 | https://en.wikipedia.org/wiki/Sultine | In chemistry, a sultine is a cyclic ester of a sulfinic acid. This class of organosulfur compounds has few applications. These compounds are typically prepared by the dehydration of hydroxy-sulfinic acids or their equivalent. Illustrative of an alternative route, xylylene dibromide reacts with sodium sulfoxylate (source of SO22-) to give the sultine C6H4(CH2S(O)OCH2), which is a precursor to o-quinodimethane.
References
Functional groups
Sulfinic acids
Organosulfur compounds | Sultine | [
"Chemistry"
] | 129 | [
"Organic compounds",
"Organosulfur compounds",
"Functional groups"
] |
67,736,378 | https://en.wikipedia.org/wiki/Xylylene%20dibromide | Xylylene dibromide is an organic compound with the formula C6H4(CH2Br)2. It is an off-white solid that, like other benzyl halides, is strongly lachrymatory. It is a useful reagent owing to the convenient reactivity of the two C-Br bonds. Two other isomers are known, para- and meta-xylylene dibromide.
Synthesis
It is prepared by the photochemical reaction of ortho-xylene with bromine:
C6H4(CH3)2 + 2Br2 → C6H4(CH2Br)2 + 2 HBr
Reactions
Further bromination gives the tetrabromide:
C6H4(CH2Br)2 + 2Br2 → C6H4(CHBr2)2 + 2 HBr
Upon reaction with thiourea followed by hydrolysis of the intermediate bisisothiouronium salts, xylylene dibromide can be converted to the dithiol C6H4(CH2SH)2.
Xylylene dibromide is a precursor to the ephemeral molecule ortho-quinonedimethane, also known as xylylene. This species can be trapped when the dehalogenation is conducted in the presence of iron carbonyl.
Coupling of xylylene dibromide by treatment with lithium metal gives dibenzocyclooctane, precursor to dibenzocyclooctadiene.
Related compounds
Xylylene dichloride, the dichloro analogue of the title compound.
Benzyl bromide, the simplest benzylic bromide.
References
Organobromides
Benzyl compounds
Lachrymatory agents | Xylylene dibromide | [
"Chemistry"
] | 369 | [
"Lachrymatory agents",
"Chemical weapons"
] |
67,738,643 | https://en.wikipedia.org/wiki/Adintoviridae | Adintoviridae is a family of viruses.
Taxonomy
The family contains the following two genera, which contain one species each:
Alphadintovirus
Alphadintovirus mayetiola
Betadintovirus
Betadintovirus terrapene
References
Virus families | Adintoviridae | [
"Biology"
] | 52 | [
"Virus stubs",
"Viruses",
"Tree of life (biology)",
"Microorganisms"
] |
67,739,924 | https://en.wikipedia.org/wiki/Lower%20envelope | In mathematics, the lower envelope or pointwise minimum of a finite set of functions is the pointwise minimum of the functions, the function whose value at every point is the minimum of the values of the functions in the given set. The concept of a lower envelope can also be extended to partial functions by taking the minimum only among functions that have values at the point. The upper envelope or pointwise maximum is defined symmetrically. For an infinite set of functions, the same notions may be defined using the infimum in place of the minimum, and the supremum in place of the maximum.
For continuous functions from a given class, the lower or upper envelope is a piecewise function whose pieces are from the same class. For functions of a single real variable whose graphs have a bounded number of intersection points, the complexity of the lower or upper envelope can be bounded using Davenport–Schinzel sequences, and these envelopes can be computed efficiently by a divide-and-conquer algorithm that computes and then merges the envelopes of subsets of the functions.
For convex functions or quasiconvex functions, the upper envelope is again convex or quasiconvex. The lower envelope is not, but can be replaced by the lower convex envelope to obtain an operation analogous to the lower envelope that maintains convexity. The upper and lower envelopes of Lipschitz functions preserve the property of being Lipschitz. However, the lower and upper envelope operations do not necessarily preserve the property of being a continuous function.
References
Functional analysis | Lower envelope | [
"Mathematics"
] | 311 | [
"Functional analysis",
"Mathematical objects",
"Functions and mappings",
"Mathematical relations"
] |
67,740,110 | https://en.wikipedia.org/wiki/Geometric%20and%20Topological%20Inference | Geometric and Topological Inference is a monograph in computational geometry, computational topology, geometry processing, and topological data analysis, on the problem of inferring properties of an unknown space from a finite point cloud of noisy samples from the space. It was written by Jean-Daniel Boissonnat, Frédéric Chazal, and Mariette Yvinec, and published in 2018 by the Cambridge University Press in their Cambridge Texts in Applied Mathematics book series. The Basic Library List Committee of the Mathematical Association of America has suggested its inclusion in undergraduate mathematics libraries.
Topics
The book is subdivided into four parts and 11 chapters. The first part covers basic tools from topology needed in the study, including simplicial complexes, Čech complexes and Vietoris–Rips complex, homotopy equivalence of topological spaces to their nerves, filtrations of complexes, and the data structures needed to represent these concepts efficiently in computer algorithms. A second introductory part concerns material of a more geometric nature, including Delaunay triangulations and Voronoi diagrams, convex polytopes, convex hulls and convex hull algorithms, lower envelopes, alpha shapes and alpha complexes, and witness complexes.
With these preliminaries out of the way, the remaining two sections show how to use these tools for topological inference. The third section is on recovering the unknown space itself (or a topologically equivalent space, described using a complex) from sufficiently well-behaved samples. The fourth part shows how, with weaker assumptions about the samples, it is still possible to recover useful information about the space, such as its homology and persistent homology.
Audience and reception
Although the book is primarily aimed at specialists in these topics, it can also be used to introduce the area to non-specialists, and provides exercises suitable for an advanced course. Reviewer Michael Berg evaluates it as an "excellent book" aimed at a hot topic, inference from large data sets, and both Berg and Mark Hunacek note that it brings a surprising level of real-world applicability to formerly-pure topics in mathematics.
References
Mathematics books
Computational geometry
Computational topology
Geometry processing
2018 non-fiction books
Cambridge University Press books | Geometric and Topological Inference | [
"Mathematics"
] | 436 | [
"Computational topology",
"Topology",
"Computational mathematics",
"Computational geometry"
] |
67,740,718 | https://en.wikipedia.org/wiki/Perfluorohexanesulfonic%20acid | Perfluorohexanesulfonic acid (PFHxS) (conjugate base perfluorohexanesulfonate) is a synthetic chemical compound. It is one of many compounds collectively known as per- and polyfluoroalkyl substances (PFASs). It is an anionic fluorosurfactant and a persistent organic pollutant with bioaccumulative properties. Although the use of products containing PFHxS and other PFASs have been banned or are being phased out in many jurisdictions, it remains ubiquitous in many environments and within the general population, and is one of the most commonly detected PFASs.
Production
PFHxS, its salts and isomers are anthropogenic chemicals that do not occur naturally. It is used as a surfactant and protective coating in applications such as aqueous firefighting foams, textile coating, metal plating and in polishing agents. PFHxS production is slowly being phased out since 3M stopped producing C6 fluorotelomers in 2002, but production by other companies may be ongoing. Between 1958 and 2015, an estimated 120-1022 metric tonnes of PFHxS were produced. PFHxS was also used as replacement for PFOS after the Stockholm Convention on persistent organic pollutants restricted the use of PFOS. The exact quantity of PFHxS produced or in production is difficult to estimate, as production volumes and relevant formulation information is often not publicly available. PFHxS may also be formed as an impurity of PFOS production, or as a breakdown product of larger PFASs.
Biochemical properties
PFHxS has a six carbon fluorocarbon chain that is both hydrophobic and lipophobic. Its sulfonic acid functional group imparts polarity, and allows it to interact with other polar compounds. Due to the strength of its carbon-fluorine bonds, it persists in the environment and in living organisms.
In humans, PFHxS binds to blood albumin, and relatively little PFHxS is found in the liver compared to longer chain PFASs such as PFOS. The half-life of PFHxS in adult blood serum is 5.3 years (4.7 years for women and 7.4 years for men).The half-life of PFASs in human blood generally decreases with decreasing backbone (CF2) length. However, PFHxS is an unusual exception in that its half-life is greater than both longer and shorter chain equivalents such as PFOS or PFBS.
Occurrence in Humans
Data from the 2003-2004 National Health and Nutrition Examination Survey in the United States found the average serum concentration of PFHxS in the general US population to be 1.9 μg/L, with the 10th and 90th percentiles being 0.7 and 8.3 μg/L, respectively. Some studies reported serum PFHxS concentrations in the United States to be gradually decreasing since at least 1999. Nevertheless, evidence of exposure can be detected amongst people with historic exposure. Serum concentrations of PFHxS were elevated amongst a cohort of Australian firefighters with occupational exposure to PFHxS (mean = 33 μg/L) compared to the general Australian population (mean = 3.2 μg/L), and were significantly correlated with serum PFOS concentrations. As with PFOS, serum PFHxS concentrations are lower amongst women and people who reported blood donation.
There is limited evidence for a relationship between PFHxS exposure and various health outcomes. However, contributions from PFHxS specifically are difficult to isolate, as most studies in humans and higher order organisms investigate exposure to a complex mixture of PFASs, of which PFHxS is just one component.
Regulatory status
A number of jurisdictions have guidelines or limits for the concentration of PFHxS in water, in diets, and in the environment. There are fewer regulations on PFHxS compared to PFOS and PFOA. This reflects the relative lack of epidemiological and toxicological information on the human health effects of exposure to PFHxS.
PFHxS, its salts and related compounds have been recommended to be added to Annex A of the United Nations Stockholm Convention on Persistent Organic Pollutants. The decision was initially scheduled to be made in June 2021. Due to the COVID-19 pandemic, the decision at the conference of parties was deferred to June 2022, where the parties agreed to list PFHxS, its salts and related compounds in Annex a without specific exemptions. Upon entry into force, nations party to the convention are legally bound to take act to cease production and use of PFHxS. Several hundred salts and precursors of PFHxS fall within the scope of the restriction.
Australia
Food Standards Australia New Zealand found insufficient evidence to justify a tolerable daily intake (TDI) for PFHxS specifically. Therefore, the TDI level for PFOS (0.02 μg/kg) was adapted as the TDI for the sum of PFOS and PFHxS. Australia uses a drinking water guideline value of 0.07 μg/L for the sum of PFHxS and PFOS. In comparison, the drinking water guideline value for PFOA is 0.56 μg/L.
Europe
A new EU drinking water directive issued in 2020 adopted PFAS limit values. The limit values are 0.1 μg/L for the sum of 20 PFASs including PFHxS, and 0.5 μg/L for the sum of all PFASs. This directive is binding for all EU member nations. It is a minimum directive, and member states can elect to adopt stricter regulations.
Denmark
The Danish EPA has established a drinking water and groundwater limit value of 2 ng/L for the sum of 4 PFASs; , PFHxS, PFOS, PFOA, and perfluorononanoic acid (PFNA).
Sweden
The Swedish National Food Agency recommends a drinking water limit of 0.09 μg/L for the sum of 11 PFASs (PFBS, PFHxS, PFOS, 6:2 FTSA, PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA and PFDA). If PFASs are found above this limit in drinking water, immediate action is recommended to reduce the PFAS concentration in the drinking water to as far below the action level as possible. If PFASs is found above 900 ng/L in drinking water, the advice is to avoid drinking the water or preparing food with the water until the concentration is reduced as low as possible below 90 ng/litre, and to contact the Swedish Food Agency.
Republic of Korea
In 2018, a preliminary drinking water limit value of 0.48 μg/L was adopted for PFHxS. In comparison, the preliminary limit value for the sum of PFOS and PFOA is 0.07 μg/L.
United States
As of 2019, there is no federal limit or guideline value for PFHxS. The United States Environmental Protection Agency (EPA) is developing toxicity values for PFHxS, as well as PFBA, PFHxA, PFNA and PFDA. Meanwhile, some states have adopted their own guideline values for PFHxS. For example, Minnesota recommends a guidance value of 0.027 μg/L for PFHxS, and Michigan has a screening level of 0.084 μg/L for PFHxS.
In 2020, Michigan adopted drinking water standards for 5 previously unregulated PFASs including PFHxS, which has a maximum contaminant level (MCL) of 51 parts per trillion (ppt) or 0.051 μg/L.
See also
Perfluorooctanesulfonic acid
Per- and polyfluoroalkyl substances
Timeline of events related to per- and polyfluoroalkyl substances
References
External links
Minnesota guidance on PFHxS
Anionic surfactants
Persistent organic pollutants under the Stockholm Convention
Endocrine disruptors
Perfluorosulfonic acids | Perfluorohexanesulfonic acid | [
"Chemistry"
] | 1,794 | [
"Endocrine disruptors",
"Persistent organic pollutants under the Stockholm Convention"
] |
67,740,765 | https://en.wikipedia.org/wiki/Guaianolide | In organic chemistry, a guaianolide is a type of sesquiterpene lactone consisting of a gamma-lactone and either a cyclopentane or cyclopentene, both fused to a central cycloheptane or cycloheptene structure. There are two subclasses, structural isomers differing in the location that part of the lactone is bonded to the central ring, known as 6,12-guaianolides and 8,12-guaianolides.
Because some of the natural products in this class of tricyclic phytochemical have been found to be potentially biologically active, there has been interest in their chemical syntheses. The full biosynthetic origin of most of the known guaianolides has not been established, but the pathway is generally presumed to begin with the formation of a germacrene lactone derived from farnesyl pyrophosphate.
References
Sesquiterpene lactones
Heterocyclic compounds with 3 rings | Guaianolide | [
"Chemistry"
] | 221 | [
"Organic chemistry stubs"
] |
67,741,333 | https://en.wikipedia.org/wiki/Flora%20Iranica | Flora Iranica is a series of books on the flora of Iranian highlands and adjacent mountains in Iran, Afghanistan, Pakistan, Iraq, Azerbaijan and Turkmenistan. The general editor of the series was the Austrian botanist Karl Heinz Rechinger (1963 - 1998).
It included genera from plants such as the genus Ferula (53 species) within the Apiaceae family, the genus Cousinia (353 species) within the Asteraceae, 126 genera within the Brassicaceae, the genera Astragalus (with approx. more than 1000 species) within the Fabaceae, the genus Nepeta (59 species) within the Lamiaceae and the genus Acantholimon (164 species) within the Plumbaginaceae family.
From 1963 up to 2005, 176 fascicles of Flora Iranica were published holding details about 9977 species and 1471 genera. A total number of 3318 species were mentioned as endemic to the Flora Iranica area (33%) and this included 1490 species which are known as endemic to Iran (24%). Up to 97 botanist from 20 different countries have contributed to Flora Iranica, which includes 10065 pages of text and 5873 pages of high quality black/white tabulae (pictures) of herbarium specimens and also 204 colour illustrations of 397 pictures.
References
Florae (publication)
Botany in Asia
Publications established in 2015 | Flora Iranica | [
"Biology"
] | 285 | [
"Flora",
"Florae (publication)"
] |
67,744,467 | https://en.wikipedia.org/wiki/Ultrastar%20%28WD%20brand%29 | Ultrastar is a Western Digital brand of enterprise-class high performance 3.5-inch hard disk drives (HDDs) and solid-state drives (SSDs). For years the product line holds a reputation of the most reliable magnetic storage on the market.
History
The brand was originally introduced by IBM in 1994 for enterprise-level HDDs together with home-computing oriented Deskstar model. These drives were based on revolutionary metalized glass disk technology. In 2003 IBM's HDD business was acquired by Hitachi, reorganized as Hitachi Global Storage Technologies(HGST) which was sold, splitting the business between Western Digital and Toshiba in 2012. The part acquired by Western Digital has retained the "HGST Ultrastar" brand name. Western Digital continued using the HGST prefix on product labels, slowly phasing it out. This resulted in that some models were sold under both HGST and WD branding simultaneously (e.g. the HGST Ultrastar He10 and WD Ultrastar HC510 are the same models of HDD).
These drives are typically used with enterprise computer systems. The two 1994 models, the 10.8 GB Ultrastar2 and the 8.7 GB Ultrastar2 XP were offered with a variety of interfaces including Fast SCSI, Fast-Wide SCSI, SCA 80-pin connectors, and Serial Storage Architecture. Evaluations units were available in the third quarter of 1995.
Current HDD models are offered with capacities up to 28 TB and with SATA or SAS interfaces.
Current SSD models are offered with capacities up to 61.44 TB and with SATA and NVMe interface.
Controversies
The IBM's revolutionary technology of metal-coated glass plates initially was plagued with bad adhesion of the metal layer and its consequent delamination with irreparable disk failure. This problem was particularly common in sibling Deskstar DTLA series drives.
As of January 2025, Western Digital follows dishonest internal policy of refusing to update the warranty status (warranty start date) for the drives purchased 1 year and later after manufacturing. This effectively decimates the promised 5-years warranty for drives purchased from the retailer stocks to shorter terms.
Wester digital also refuses warranty claims by private customers for OEM drives, which constitute the main mass of drives sold by the Internet retailers.
After acquiring, Western Digital started shipping "Refurbished" and "Recertified" second-hand Ultrastar drives from data-centers cheaply in large amounts, which is actively used by the Internet cons, selling them as new.
See also
Deskstar
Travelstar
References
Computer storage devices
Divested IBM products
Hitachi products
IBM storage devices
Western Digital products | Ultrastar (WD brand) | [
"Technology"
] | 558 | [
"Computing stubs",
"Computer hardware stubs"
] |
67,744,691 | https://en.wikipedia.org/wiki/Island%20syndrome | Island syndrome describes the differences in morphology, ecology, physiology and behaviour of insular species compared to their continental counterparts. These differences evolve due to the different ecological pressures affecting insular species, including a paucity of large predators and herbivores as well as a consistently mild climate.
Ecological driving factors
Reduced predation. Island ecosystems cannot support a sufficient biomass of prey in order to accommodate large predators. This largely relieves prey species of the risk of predation, which mostly removes the selection pressure for morphologies, ecologies and behaviours that help to evade large predators.
Reduced biodiversity. Insular ecosystems tend to comprise large populations of a limited number of species (a state termed density compensation), therefore, they exhibit low biodiversity. This results in reduced interspecific competition and increased intraspecific competition.
Reduced sexual selection. There is also reduced sexual selection in insular species, which is especially prominent in birds which lose their sexually dimorphic plumage used in sexual displays.
Reduced parasite diversity. Finally, there is reduced parasite diversity in insular ecosystems which reduces the level of selection acting on immune-related genes.
Features of island syndrome in animals
Body size
Interspecific competition between continental species drives divergence of body size so that species may avoid high levels of competition by occupying distinct niches. Reduced interspecific competition between insular species reduces this selection pressure for species to occupy distinct niches. As a result, there is less diversity in the body size of insular species. Typically small mammals increase in size (for example fossa are a larger insular relative of the mongoose) while typically large mammals decrease in size (for example the Malagasy hippopotamuses are smaller insular relatives of continental hippopotamuses). These are examples of insular gigantism and insular dwarfism respectively. This observed effect is called Foster's rule. Conversely, birds and reptiles tend to exhibit insular gigantism, exemplified by the moa, cassowary and Komodo dragon.
Although the giant tortoises of the Galápagos Islands and the Seychelles (the Galápagos tortoise and Aldabrachelys respectively) are sometimes given as examples of insular gigantism, they are now thought to represent the last remaining populations of historically widespread giant tortoises. The remains of tortoises of similar or larger size have been found in Australia (Meiolania), southern Asia (Megalochelys), Madagascar (Aldabrachelys), North America (Hesperotestudo) and South America (Chelonoidis). The extant giant tortoises are thought to persist only in a few remote archipelagos because humans arrived there relatively late and have not heavily predated them, suggesting that these tortoise populations have been less subjected to overexploitation.
Locomotion
Since insular prey species experience a reduced risk of predation, they often lose or reduce morphologies utilised in predator evasion. For example, the wings of weevils, rails and pigeons have become so reduced in insular species that many have lost the ability to fly. This has occurred in several ratites including the kiwi and the cassowary as well as in the dodo and the kākāpō after invading island habitats. The extinct moa of New Zealand exhibit the most extreme known example of insular wing reduction; there is no osseous evidence of even vestigial wings and the pectoral girdle is reduced to a scapulocoracoideum which would be unable to bear a forelimb as it lacks a glenoid fossa. Therefore, it is the only bird known to have completely lost its wings after a shift to insularity. Loss of flight allows birds to eliminate the costs of maintaining large flight-enabling muscles like the pectoral muscles and allows the skeleton to become heavier and stronger. Insular populations of barn owl have shorter wings, representing a transitional stage in which their capacity for flight is being reduced.
Adaptive coloration
Due to the reduced sexual selection of insular species, they tend to exhibit reduced sexual coloration so as to conserve the energy that this demands. Additionally, the low biodiversity of insular ecosystems makes species recognition less important so species-specific coloration is under less selection. As a result, insular bird species often exhibit duller, sexually monomorphic plumage.
Several insular species acquire increased melanin colouration. Male white-winged fairywrens living on mainland Australia exhibit a blue nuptial plumage, whereas two island subspecies (Malurus leucopterus leucopterus from Dirk Hartog Island and Malurus leucopterus edouardi from Barrow Island) exhibit a black nuptial plumage. A subspecies of the chestnut-bellied monarch endemic to the Solomon Islands, Monarcha castaneiventris obscurior, exhibits polymorphism in plumage color: some birds are black with a chestnut-colored belly while others are completely melanic. The frequency of the melanic phenotype increases on smaller islands, even when the relative proximity of the islands is accounted for.
Reproduction
High levels of intraspecific competition between offspring selects for the very fittest individuals. As a result, insular parents tend to produce fewer offspring so that each offspring receives greater parental investment, maximising their fitness. Lizards endemic to island ecosystems lay smaller clutches that give larger offspring compared to continental lizards of a similar size. Because of increased frequency of laying in insular lizards, continental and insular lizards produced offspring at a comparable rate.
Brain size
The expensive tissue hypothesis suggests that tissues with a high metabolic demand like the brain will become reduced if they confer little selective advantage and so do not help to increase food intake. The paucity of large predators means that insular species can afford to become slower and less alert without suffering from massively increased predation risk. As such, reduction in relative brain size is often seen in insular species as this reduces basal metabolic rate without increases in predation risk. For example, the endocranial volume of the extinct Malagasy dwarf hippos is 30% less than that of an equally sized continental ancestor. Similarly, the early human, Homo floresiensis, had a brain of similar size to that of the significantly earlier Australopithecus specimens from mainland Africa and 3.4 times smaller than that of Homo sapiens which evolved later (see Evolution of human brain size).
Poikilothermy
Due to low predation risk, insular prey species can afford to reduce their basal metabolic rate by adopting poikilothermy without any significant increase in predation risk. As a result, poikilothermy is far more common in island species.
Behaviour
Due to lack of predation, insular species tend to become more docile and less territorial than their continental counterparts (sometimes referred to as island tameness). Deer mice, song sparrows and bronze anoles all have smaller territories with greater overlap compared to their mainland conspecifics. They are also more tolerant to intruders. Falkland Island foxes and Tammar wallabies have both lost an innate fear of large predators including humans.
In parasites
The nematode parasite Heligmosomoides polygyrus underwent niche expansion (by invading new host species) and a reduction in genetic diversity after invading ecosystems in seven western Mediterranean islands. The loss of genetic diversity was related to the distance between the contemporal population and the mainland origin.
In plants
Plant structure
Plant stature and leaf area both follow the pattern of insular mammals, with small species becoming larger and large species becoming smaller in island populations. This may be due to reduced interspecific competition which would decrease the ecological drive for plants to occupy separate niches. Due to reduced biomass of large herbivores, several island plants lose protective spines and thorns as well as decreasing the amounts of defensive chemicals produced. The improbability of island fires also results in a loss of fire-resistance in bark, fruits and cones. Insular woodiness, the evolutionary transition from herbaceousness toward woodiness, is a very common phenomenon among island floras.
Reproduction and dispersal
Due to a lack of dedicated pollinators on remote islands, insular plants often use small, inconspicuously colored and easily accessible flowers to attract a range of alternative pollinator species. Self-pollination is also more commonly used by insular plant species, as pollen does not have to travel so far to reach a receptive ovule or stigma.
Seeds exhibit insular gigantism, becoming predominantly larger than mainland seeds, which is thought to improve mortality at sea during dispersal.
Consequences of island syndrome for conservation
The relaxed predation risk in island ecosystems has resulted in the loss of several adaptations and behaviours that act to evade or discourage predation. This makes insular species particularly vulnerable to exploitation by alien species. For example, when humans first introduced dogs, pigs, cats, rats, and crab-eating macaques to the island of Mauritius in the 17th century, they plundered dodo nests and increased interspecies competition for the limited food resources. This ultimately resulted in the dodo's extinction. The limited resources in island ecosystems are also vulnerable to overexploitation if they are not managed sustainably.
Hațeg Island
Hațeg Island was a large offshore island in the Tethys Sea of the Late Cretaceous and is often called "The Island of the Dwarf Dinosaurs" on account of the extensive fossil evidence that its native dinosaurs exhibited island dwarfism. The island's native titanosaur, Magyarosaurus dacus, had a body mass of only while mainland titanosaurs like Patagotitan could reach up to . The pterosaur Hatzegopteryx took over the position of apex predator of Hațeg Island in the absence of any hypercarnivorous dinosaurs and likely hunted juvenile dwarf dinosaurs or even adults of the smaller species. Based on its robust jaw and cervical vertebrae, Hatzegopteryx is thought to have hunted in a similar manner to modern storks by attacking prey that are too large to swallow whole. Its wingspan is estimated to have reached up to 10 to 12 metres (33 to 39 ft), making it one of the largest pterosaurs to have ever lived. As such, it is a potent example of island gigantism, in this case to fill the otherwise empty niche of apex predator. Balaur bondoc was originally classified as a dromaeosaurid dinosaur based on its retractable toe claws. Its forelimbs appeared to be too short and stocky for it to be a basal avialan, however, phylogenetic analysis later confirmed that Balaur was indeed a basal member of Avialae, a clade that includes modern birds. Its limbs were clearly incapable of powered flight and so Balaur is yet another example of the secondary loss of flight after invading an island niche, similar to ratites as well as the extinct moa and the dodo (See Insular reduction in flight capacity).
Reversed island syndrome
The term "reversed island syndrome" (RIS) was first used by Pasquale Raia in 2010 to describe the differences in morphology, ecology, physiology and behaviour observed in insular species when population density is either low or fluctuating. This results in stronger natural selection and weaker intraspecific selection, leading to different phenotypes compared to the standard island syndrome.
RIS was first described in a population of Italian wall lizard endemic to the Licosa Islet where the unpredictable environmental conditions and highly fluctuating population density have selected for aggressive behaviour and increased reproductive effort. The male lizards exhibit elevated α-MSH levels relative to mainland populations, which increases the basal metabolic rate, strengthens immune responses, produces darker blue coloration and raises 5α-dihydrotestosterone levels. The latter improves male reproductive success by increasing the likelihood of winning sexual conflicts over females and augmenting sperm quality. Females produce similar numbers of eggs compared to mainland populations but the eggs of insular females are significantly heavier, reflecting increased reproductive effort. The unpredictable conditions produce high mortality rates so adults invest more effort into current broods since they are less likely to survive to produce subsequent broods i.e. there is low interbrood conflict.
References
See also
Island ecology
Morphology (biology)
Islands
Physiology | Island syndrome | [
"Biology"
] | 2,530 | [
"Physiology",
"Morphology (biology)"
] |
67,745,009 | https://en.wikipedia.org/wiki/Jin-Quan%20Yu | Jin-Quan Yu () is a Chinese-born American chemist. He is the Frank and Bertha Hupp Professor of Chemistry at Scripps Research, where he also holds the Bristol Myers Squibb Endowed Chair in Chemistry. He is a 2016 recipient of the MacArthur Fellowship, and is a member of the American Academy of Arts and Sciences, American Association for the Advancement of Science, and the Royal Society of Chemistry. Yu is a leader in the development of C–H bond activation reactions in organic chemistry, and has reported many C–H activation reactions that could be applicable towards the synthesis of drug molecules and other biologically active compounds. He also co-founded Vividion Therapeutics in 2016 with fellow Scripps chemists Benjamin Cravatt and Phil Baran, and is a member of the scientific advisory board of Chemveda Life Sciences.
Early life and education
Yu was born on January 10, 1966, in Zhejiang, China. He received his B.Sc. in chemistry at East China Normal University in 1987. Yu then went on to the Guangzhou Institute of Chemistry, Chinese Academy of Sciences where he worked on heterogeneous reactions of terpenes with zeolite materials with Prof. Shu-De Xiao, obtaining his M.Sc. in 1990. He remained at the Guangzhou Institute of Chemistry for four years as a research associate.
In 1994, Yu moved to the United Kingdom to pursue graduate studies at the University of Cambridge with Prof. Jonathan B. Spencer. At Cambridge, he studied biosynthesis and the mechanistic details of the hydrometallation step in asymmetric hydrogenation reactions with heterogeneous and homogeneous catalysts, among the twenty-one papers he co-authored with Spencer. Yu graduated with his Ph.D. in 1999.
Between 1999 and 2001, Yu worked as a Junior Research Fellow of St John's College, Cambridge. From 2001-2002, Yu worked as a postdoctoral fellow at Harvard University in the laboratory of Prof. E. J. Corey on selective palladium-catalyzed allylic oxidation reactions. Yu returned to Cambridge in 2002 and continued in his position as a Junior Research Fellow.
Independent career
Yu was awarded a Royal Society University Research Fellowship in 2003, which allowed him to start his independent research towards the development of asymmetric C–H activation reactions. In 2004, he moved to Brandeis University as an assistant professor of chemistry. He moved to The Scripps Research Institute as an associate professor in 2007 and was promoted to full professor in 2010. In 2012, he was appointed the Frank and Bertha Hupp Professor of Chemistry.
Research
Yu is an organic synthetic chemist who develops of new methods for functionalizing carbon-hydrogen (C–H) bonds, or C–H activation. A longstanding goal in organic synthesis, C–H activation would allow for inert, unreactive C–H bonds to be replaced with bonds to functional groups that can alter a molecule's reactivity and properties. One strategy to achieve selective C–H activation under mild conditions is to use metal-based catalysts that are guided to the targeted C–H bond by nearby directing functional groups. These directing groups often must be removed once the new functional group has been appended to the molecule. This style of C–H activation methodology could greatly simplify the synthesis of pharmaceutical drug molecules, agrochemicals, and natural products.
Yu has contributed metal palladium-catalyzed C-H bond activation promoted by "weak coordination," that is by directing group effects. Other areas of interest are the development of remote C-H bond activation, for example at the meta-position to a directing group. Since many drugs and natural products are chiral, Yu has also developed important asymmetric C-H bond activation reactions, including those templated by modified amino acids that can act as transient, chiral directing groups.
Awards and memberships
Yu is the recipient of numerous awards and honors for his work in organic chemistry reaction development, including a MacArthur Fellowship (also known as a "Genius Grant") in 2016. He was elected a member of the American Academy of Arts and Sciences in 2019, a fellow of the American Association for the Advancement of Science and the Royal Society of Chemistry in 2012. In 2013, he received the Raymond and Beverly Sackler Prize in the Physical Sciences.
Yu received the Pedler Award from the Royal Society of Chemistry in 2016, and the Elias J. Corey Award for Outstanding Original Contribution in Organic Synthesis by a Young Investigator from the American Chemical Society. In 2012, he was awarded the Mukaiyama Award from the Japanese Society of Organic Synthesis, the ACS Cope Scholar Award, and the Bristol-Myers Squibb Award. His honors also include the Novartis Early Career Award in Organic Chemistry (2011), Eli Lilly Grantee Award (2008), Amgen Young Investigator's Award (2008), and Sloan Research Fellowship (2008).
Personal life
Yu has a son, Tony.
References
Living people
1966 births
Chinese organic chemists
American organic chemists
Scripps Research faculty
21st-century Chinese chemists
Fellows of St John's College, Cambridge
21st-century American chemists | Jin-Quan Yu | [
"Chemistry"
] | 1,053 | [
"Organic chemists",
"Chinese organic chemists",
"American organic chemists"
] |
67,746,527 | https://en.wikipedia.org/wiki/Ruma%20Falk | Ruma Falk (, née Oren-Aharonovich, 1932–2020) was an Israeli psychologist and philosopher of mathematics known for her work on probability theory and human understanding of probability and statistics.
Falk was born in Jerusalem, and educated at the Herzliya Hebrew Gymnasium and Hebrew University of Jerusalem. She completed her PhD on the perception of chance at the Hebrew University in 1975 under the supervision of Amos Tversky, and became a professor there. She was married to Raphael Falk, a geneticist and historian of science.
Falk won the George Pólya Award of the Mathematical Association of America with Maya Bar-Hillel in 1984 for their joint work on probability. She died on August 15, 2020.
Selected works
Falk was the author of books including:
Understanding Probability and Statistics: A Book of Problems (A K Peters, 1993)
אתגרים לתאים האפורים (Challenges to the Gray Cells, Poalim Library Publishing, 2004)
יש בעיה! (There is a Problem, Poalim Library Publishing, 2013)
Many Faces of the Gambler's Fallacy: Subjective Randomness and Its Diverse Manifestations (self-published, 2016)
She also created a board game, ברירה וסיכוי (Choice and Chance).
Her other publications include:
References
1932 births
2020 deaths
Israeli psychologists
Israeli mathematicians
Israeli women mathematicians
Philosophers of mathematics
Probability theorists
Hebrew University of Jerusalem alumni
Academic staff of the Hebrew University of Jerusalem
People from Jerusalem
Israeli women psychologists | Ruma Falk | [
"Mathematics"
] | 322 | [
"Philosophers of mathematics"
] |
54,992,011 | https://en.wikipedia.org/wiki/Characterization%20of%20nanoparticles | The characterization of nanoparticles is a branch of nanometrology that deals with the characterization, or measurement, of the physical and chemical properties of nanoparticles.,. Nanoparticles measure less than 100 nanometers in at least one of their external dimensions, and are often engineered for their unique properties. Nanoparticles are unlike conventional chemicals in that their chemical composition and concentration are not sufficient metrics for a complete description, because they vary in other physical properties such as size, shape, surface properties, crystallinity, and dispersion state.
Nanoparticles are characterized for various purposes, including nanotoxicology studies and exposure assessment in workplaces to assess their health and safety hazards, as well as manufacturing process control. There is a wide range of instrumentation to measure these properties, including microscopy and spectroscopy methods as well as particle counters. Metrology standards and reference materials for nanotechnology, while still a new discipline, are available from many organizations.
Background
Nanotechnology is the manipulation of matter at the atomic scale to create materials, devices, or systems with new properties or functions. It has potential applications in energy, healthcare, industry, communications, agriculture, consumer products, and other sectors. Nanoparticles measure less than 100 nanometers in at least one of their external dimensions, and often have properties different from the bulk versions of their component materials, which make them technologically useful. This article uses a broad definition of nanoparticles which includes all free nanomaterials regardless of their shape or how many of their dimensions are nanoscale, rather than the more restrictive ISO/TS 80004 definition that only refers to round nano-objects.
Nanoparticles have different analytical requirements than conventional chemicals, for which chemical composition and concentration are sufficient metrics. Nanoparticles have other physical properties that must be measured for a complete description, such as size, shape, surface properties, crystallinity, and dispersion state. The bulk properties of nanoparticles are sensitive to small variations in these properties, which has implications for process control in their industrial use. These properties also influence the health effects of exposure to nanoparticles of a given composition.
An additional challenge is that sampling and laboratory procedures can perturb the nanoparticles' dispersion state, or bias the distribution of their other properties. In environmental contexts, many methods cannot detect low concentrations of nanoparticles that may still have an adverse effect. A high background of natural and incidental nanoparticles may interfere with detection of the target engineered nanoparticle, as it is difficult to distinguish the two. Nanoparticles may also be mixed with larger particles. For some applications, nanoparticles may be characterized in complex matrices such as water, soil, food, polymers, inks, complex mixtures of organic liquids such as in cosmetics, or blood.
Types of methods
Microscopy methods generate images of individual nanoparticles to characterize their shape, size, and location. Electron microscopy and scanning probe microscopy are the dominant methods. Because nanoparticles have a size below the diffraction limit of visible light, conventional optical microscopy is not useful. Electron microscopes can be coupled to spectroscopic methods that can perform elemental analysis. Microscopy methods are destructive, and can be prone to undesirable artifacts from sample preparation such as drying or vacuum conditions required for some methods, or from probe tip geometry in the case of scanning probe microscopy. Additionally, microscopy is based on single-particle measurements, meaning that large numbers of individual particles must be characterized to estimate their bulk properties. A newer method, enhanced dark-field microscopy with hyperspectral imaging, shows promise for imaging nanoparticles in complex matrices such as biological tissue with higher contrast and throughput.
Spectroscopy, which measures the particles' interaction with electromagnetic radiation as a function of wavelength, is useful for some classes of nanoparticles to characterize concentration, size, and shape. Semiconductor quantum dots are fluorescent and metal nanoparticles exhibit surface plasmon absorbances, making both amenable to ultraviolet–visible spectroscopy. Infrared, nuclear magnetic resonance, and X-ray spectroscopy are also used with nanoparticles. Light scattering methods using laser light, X-rays, or neutron scattering are used to determine particle size, with each method suitable for different size ranges and particle compositions.
Some miscellaneous methods are electrophoresis for surface charge, the Brunauer–Emmett–Teller method for surface area, and X-ray diffraction for crystal structure; as well as mass spectrometry for particle mass, and particle counters for particle number. Chromatography, centrifugation, and filtration techniques can be used to separate nanoparticles by size or other physical properties before or during characterization.
Metrics
Size and dispersion
Particle size is the external dimensions of a particle, and dispersity is a measure of the range of particle sizes in a sample. If the particle is elongated or irregularly shaped, the size will differ between dimensions, although many measurement techniques yield an equivalent spherical diameter based on the surrogate property being measured. Size can be calculated from physical properties such as settling velocity, diffusion rate or coefficient, and electrical mobility. Size can also be calculated from microscope images using measured parameters such as Feret diameter, Martin diameter and projected area diameters; electron microscopy is often used for this purpose for nanoparticles. Size measurements may differ between methods because they measure different aspects of particle dimensions, they average distributions over an ensemble differently, or the preparation for or operation of the method may change the effective particle size.
For airborne nanoparticles, techniques for measuring size include cascade impactors, electrical low-pressure impactors, mobility analyzers, and time-of-flight mass spectrometers. For nanoparticles in suspension, techniques include dynamic light scattering, laser diffraction, field flow fractionation, nanoparticle tracking analysis, particle tracking velocimetry, size exclusion chromatography, centrifugal sedimentation, and atomic force microscopy. For dry materials, techniques for measuring size include electron microscopy, atomic force microscopy, and X-ray diffraction. Back-calculation from surface area measurements are commonly employed, but these are subject to error for porous materials. Additional methods include hydrodynamic chromatography, static light scattering, multiangle light scattering, nephelometry, laser-induced breakdown detection, and ultraviolet–visible spectroscopy; as well as near-field scanning optical microscopy, confocal laser scanning microscopy, capillary electrophoresis, ultracentrifugation, cross-flow filtration, small-angle X-ray scattering, and differential mobility analysis. Use of an environmental scanning electron microscope avoids morphological changes caused by the vacuum required for standard scanning electron microscopy, at the cost of resolution.
A closely related property is dispersion, a measure of the degree to which particles clump together into agglomerates or aggregates. While the two terms are often used interchangeably, according to ISO nanotechnology definitions, an agglomerate is a reversible collection of particles weakly bound, for example by van der Waals forces or physical entanglement, whereas an aggregate is composed of irreversibly bonded or fused particles, for example through covalent bonds. Dispersion is often assessed using the same techniques employed to determine size distribution, and the width of a particle size distribution is often used as a surrogate for dispersion. Dispersion is a dynamic process strongly affected by properties of the particles themselves as well as their environment such as pH and ionic strength. Some methods have difficulty distinguishing between a single large particle and a set of smaller agglomerated or aggregated particles; in this case using multiple sizing methods can help resolve the ambiguity, with microscopy being particularly useful.
Shape
Morphology refers to the physical shape of a particle, as well as its surface topography, for example, the presence of cracks, ridges, or pores. Morphology influences dispersion, functionality, and toxicity, and has similar considerations as size measurements. Evaluation of morphology requires direct visualization of the particles through techniques like scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Several metrics can be used, such as sphericity or circularity, aspect ratio, elongation, convexity, and fractal dimension. Because microscopy involves measurements of single particles, a large sample size is necessary to ensure a representative sample, and orientation and sample preparation effects must be accounted for.
Chemical composition and crystal structure
Bulk chemical composition refers to the atomic elements of which a nanoparticle is composed, and can be measured in ensemble or single-particle elemental analysis methods. Ensemble techniques include atomic absorption spectroscopy, inductively coupled plasma optical emission spectroscopy or inductively coupled plasma mass spectrometry, nuclear magnetic resonance spectroscopy, neutron activation analysis, X-ray diffraction, X-ray absorption spectroscopy, X-ray fluorescence, and thermogravimetric analysis. Single-particle techniques include time-of-flight mass spectrometry, as well as utilizing elemental detectors such as energy-dispersive X-ray analysis or electron energy loss spectroscopy while using scanning electron microscopy or transmission electron microscopy.
The arrangement of elemental atoms in a nanoparticles may be organized into a crystal structure or may be amorphous. Crystallinity is the ratio of crystalline to amorphous structure. Crystallite size, the size of the crystal unit cell, can be calculated through the Scherrer equation. Generally, crystal structure is determined using powder X-ray diffraction, or selected area electron diffraction using a transmission electron microscope, though others such as Raman spectroscopy exist. X-ray diffraction requires on the order of a gram of material, whereas electron diffraction can be done on single particles.
Surface area
Surface area is an important metric for engineered nanoparticles because it influences reactivity and surface interactions with ligands. Specific surface area refers to the surface area of a powder normalized to mass or volume. Different methods measure different aspects of surface area.
Direct measurement of nanoparticle surface area utilizes adsorption of an inert gas such as nitrogen or krypton under varying conditions of pressure to form a monolayer of gas coverage. The number of gas molecules needed to form a monolayer and the cross-sectional area of the adsorbate gas molecule are related to the "total surface area" of the particle, including internal pores and crevices, using the Brunauer–Emmett–Teller equation. Organic molecules can be used in place of gasses, such as ethylene glycol monoethyl ether.
There are several indirect measurement techniques for airborne nanoparticles, which do not account for porosity and other surface irregularities and therefore may be inaccurate. Real-time diffusion chargers measure the "active surface area", the area of the particle that interacts with the surrounding gas or ions and is accessible only from the outside. Electrical mobility analyzers calculate the spherical equivalent diameter, which can be converted using geometric relationships. These methods cannot discriminate a nanoparticle of interest from incidental nanoparticles that may occur in complex environments such as workplace atmospheres. Nanoparticles can be collected onto a substrate and their external dimensions can be measured using electron microscopy, then converted to surface area using geometric relations.
Surface chemistry and charge
Surface chemistry refers to the elemental or molecular chemistry of particle surfaces. No formal definition exists for what constitutes a surface layer, which is usually defined by the measurement technique employed. For nanoparticles a higher proportion of atoms are on their surfaces relative to micron-scale particles, and surface atoms are in direct contact with solvents and influence their interactions with other molecules. Some nanoparticles such as quantum dots may have a core–shell structure where the outer surface atoms are different than those of the interior core.
Multiple techniques are available to characterize nanoparticle surface chemistry. X-ray photoelectron spectroscopy and Auger electron spectroscopy are well-suited to characterizing a thicker surface layer of 1–5 nm. Secondary ion mass spectroscopy is more useful to characterize just the top few angstroms (10 angstroms = 1 nm), and can be used with sputtering techniques to analyze chemistry as a function of depth. Surface chemistry measurements are particularly sensitive to contamination on particle surfaces, making quantitative analyses difficult, and spatial resolution can be poor. For adsorbed proteins, radiolabelling or mass spectrometry methods such as matrix-assisted laser desorption/ionization (MALDI) can be used.
Surface charge generally refers to the charge from adsorption or desorption of protons on hydroxylated sites on a nanoparticle surface. Surface charge is difficult to directly measure, so the related zeta potential is often measured instead, which is the potential at the double layer's slipping plane, which separates mobile solvent molecules from those that remain attached to the surface. Zeta potential is a calculated rather than measured property, and is a function of both the nanoparticle of interest and its surrounding medium, requiring a description of the measurement temperature; the composition, pH, viscosity, and dielectric constant of the medium; and value used for the Henry function to be meaningful. Zeta potential is used as an indicator of colloidal stability, and has been shown to be predictive of nanoparticle uptake by cells. Zeta potential can be measured by titration to find the isoelectric point, or through electrophoresis including laser Doppler electrophoresis.
Surface energy or wettability are also important for nanoparticle aggregation, dissolution, and bioaccumulation. They can be measured through heat of immersion microcalorimetry studies, or through contact angle measurements. Surface reactivity can also be directly monitored through microcalorimetry using probe molecules that undergo measurable changes.
Solubility
Solubility is a measurement of the degree to which material dissolves from a nanoparticle to enter solution. Material dissolved as part of a solubiity test can be quantified using atomic absorption spectroscopy, inductively coupled plasma optical emission spectroscopy, and inductively coupled plasma mass spectroscopy, with the last being generally the most sensitive. Two related concepts are biodurability, the rate of dissolution in a biological fluid or surrogate, and biopersistence, the rate at which a material is cleared from an organ such as the lung by physical and chemical dissolution processes.
Analytical techniques for solubility quantitatively measure total elemental concentration in a sample, and do not discriminate between dissolved or solid forms. Therefore, a separation process must be used to remove the remaining particles. Physical separation techniques include size exclusion chromatography, hydrodynamic chromatography and field flow fractionation. Mechanical separation techniques utilize membranes and/or centrifugation. Chemical separation techniques are liquid–liquid extraction, solid–liquid extraction, cloud point extraction, and the use of magnetic nanoparticles.
Applications
Product verification
Manufacturers and users of nanoparticles may perform characterization of their products for process control or verification and validation purposes. The properties of nanoparticles are sensitive to small variations in the processes used to synthesize and process them. Thus, nanoparticles prepared by seemingly identical processes must be characterized to determine if they are actually equivalent. Any material or dimensional property of a nanomaterial can be heterogeneous, and these can lead to heterogeneity in their functional properties. Generally, uniform collections are desired. It is advantageous to minimize heterogeneity during the initial synthesis, stabilization, and functionalization processes, rather than through downstream purification steps that decrease yield. Batch-to-batch reproducibility is also desirable. Unlike research-oriented nanometrology, industrial measurements emphasize reducing time, cost, and number of measured metrics, and must be performed under ambient conditions during a production process.
Different applications have different tolerances for uniformity and reproducibility, and require different approaches to characterization. For example, nanocomposite materials may be tolerant of a broad distribution of nanoparticle properties. By contrast, characterization is especially important for nanomedicines, as their efficacy and safety depends strongly on critical properties such as particle size distribution, chemical composition, and the kinetics of drug loading and release. The development of standardized analytical methods for nanomedicines is in its early stages. However, standardized lists of recommended tests called "assay cascades” have been developed to assist with this.
Toxicology
Nanotoxicology is the study of the toxic effects of nanoparticles on living organisms. Characterization of a nanoparticle's physical and chemical properties is important for ensuring the reproducibility of toxicology studies, and is also vital for studying how the physical and chemical properties of nanoparticles determine their biological effects.
The properties of a nanoparticle, such as size distribution and agglomeration state, can change as a material is prepared and used in toxicology studies. This makes it important to measure them at different points in the experiment. The "as-received" or "as-generated" properties refer to the material's state when received from the manufacturer or synthesized in the laboratory. The "as-dosed" or "as-exposed" properties refer to its state when administered to the biological system. These may differ from the "as-received" state due to formation of aggregates and agglomerates if the material has been in powder form, the settling out of larger aggregates and agglomerates, or loss by adhesion to surfaces. The properties may again be different at the point of interaction with the organism's tissues due to biodistribution and physiological clearance mechanisms. At this stage, it is difficult to measure nanoparticle properties in situ without perturbing the system. Post mortem or histological examination provides a way to measure these changes in the material, although the tissue itself can interfere with the measurements.
Exposure assessment
Exposure assessment is a set of methods used to monitor contaminant release and exposures to workers and mitigate the health and safety hazards of nanomaterials in workplaces where they are handled. For engineered nanoparticles, the assessment often involves use of both real-time instruments such as particle counters, which monitor the total number of particles in air (including both the nanoparticle of interest and other background particles), and filter-based occupational hygiene sampling methods that use electron microscopy and elemental analysis to identify the nanoparticle of interest. Personal sampling locates the samplers in the personal breathing zone of the worker, as close to the nose and mouth as possible and usually attached to a shirt collar. Area sampling is where samplers are placed at static locations.
The U.S. National Institute for Occupational Safety and Health developed a Technical Report: Occupational Exposure Sampling for Engineered Nanomaterials which contains guidance for workplace sampling for three engineered nanomaterials: carbon nanotubes and nanofibers, silver, and titanium dioxide, each of which have an elemental mass-based NIOSH Recommended Exposure Limit (REL). In addition, NIOSH developed a practical approach to exposure sampling for other engineered nanomaterials that do not have exposure limits employing the Nanomaterial Exposure Assessment Technique (NEAT) 2.0, a sampling strategy that can be used to determine exposure potential for engineered nanoparticles. The NEAT 2.0 approach uses filter samples both in the worker's personal breathing zone and as area samples. Separate filter samples are used for elemental analysis, and to gather morphologic data from electron microscopy. The latter can provide an order of magnitude evaluation of the contribution of the nanoparticle of interest to the elemental mass load, as well as a qualitative assessment of the particle size, degree of agglomeration, and whether the nanoparticle is free or contained within a matrix. Hazard identification and characterization can then be performed based on a holistic assessment of the integrated filter samples. In addition, field-portable direct reading instruments can be used for continuous recording of normal fluctuations in particle count, size distribution, and mass. By documenting the workers' activities, data-logged results can then be used to identify workplace tasks or practices that contribute to any increase or spikes in the counts. The data need to be carefully interpreted, as direct reading instruments will identify the real-time quantity of all nanoparticles including any incidental background particles such as may occur from motor exhaust, pump exhaust, heating vessels, and other sources. Evaluation of worker practices, ventilation efficacy, and other engineering exposure control systems and risk management strategies serve to allow for a comprehensive exposure assessment.
To be effective, real-time particle counters should be able to detect a wide range of particle sizes, as nanoparticles may aggregate in the air. Adjacent work areas can be simultaneously tested to establish a background concentration. Not all instruments used to detect aerosols are suitable for monitoring occupational nanoparticle emissions because they may not be able to detect smaller particles, or may be too large or difficult to ship to a workplace. Some NIOSH methods developed for other chemicals can be used for off-line analysis of nanoparticles, including their morphology and geometry, elemental carbon content (relevant for carbon-based nanoparticles), and elemental analysis for several metals.
Occupational exposure limits have not yet been developed for many of the large and growing number of engineered nanoparticles now being produced and used, as their hazards are not fully known. While mass-based metrics are traditionally used to characterize toxicological effects of exposure to air contaminants, it remains unclear which metrics are most important with regard to engineered nanoparticles. Animal and cell-culture studies have shown that size and shape may be two major factors in their toxicological effects. Surface area and surface chemistry also appear to be more important than mass concentration. NIOSH has determined non-regulatory recommended exposure limits (RELs) of 1.0 μg/m3 for carbon nanotubes and carbon nanofibers as background-corrected elemental carbon as an 8-hour time-weighted average (TWA) respirable mass concentration, and 300 μg/m3 for ultrafine titanium dioxide as TWA concentrations for up to 10 hr/day during a 40-hour work week.
Standards
Metrology standards for nanotechnology are available from both private organizations and government agencies. These include the International Organization for Standardization (ISO), ASTM International, the IEEE Standards Association (IEEE), the International Electrotechnical Commission (IEC), the International Union of Pure and Applied Chemistry, the U.S. National Institute of Standards and Technology (NIST), the U.S. National Cancer Institute's Nanotechnology Characterization Laboratory, and the European Committee for Standardization. The American National Standards Institute maintains a database of nanotechnology standards.
Reference materials
Reference materials are materials that are established or produced to be homogeneous and stable in at least one measurable physical property to provide a control measurement. Reference materials for nanoparticles can reduce measurement error that can contribute to uncertainty in their hazard properties in risk assessment. Reference materials can also be used for calibrating equipment used in nanoparticles characterization, for statistical quality control, and for comparing experiments run in different laboratories.
Many nanoparticles do not yet have reference materials available. Nanoparticles have the challenge that reference materials can only be generated when the measurement methods themselves can produce precise and reproducible measurements of the relevant physical property. Measurement conditions must also be specified, because properties such as size and dispersion state may change based on them, especially when there is a thermodynamic equilibrium between particlulate and dissolved matter. Reference materials of nanoparticles often have a shorter validity period than other materials. Those in powder form are more stable than those provided in suspensions, but the process of dispersing the powder increases uncertainty in its metrics.
Reference nanoparticles are produced by the U.S. National Institute of Standards and Technology, as well as the European Union Institute for Reference Materials and Measurements, the Japanese National Institute of Advanced Industrial Science and Technology, the Canadian National Research Council, the Chinese National Institute of Metrology, and Thermo Fisher Scientific. The German Federal Institute for Materials Research and Testing maintains a listing of nanoscale reference materials.
References
Metrology
Analytical chemistry | Characterization of nanoparticles | [
"Chemistry"
] | 5,063 | [
"nan"
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.