As one of the creators of both Tribe Retreats and Solare Yoga & Detox Retreats, I am proud to present our various three and five night wellness retreats throughout Italy including yoga, adventure, travel, nutrition and holistic wellness- with promises to detoxify the body, calm the mind, and enliven the soul.

Tribe Retreats: The word Tribe is for community, where we create friendships and bonds that hold us up and help us heal. At Tribe Retreats, individuals come together to take a step back from the daily grind to rejuvenate the body and feed the soul. Our retreaters explore the beauty and culture of different regions of Italy, deepen their yoga practices, gain mental focus through meditation and mindfulness activities, and expand their knowledge of nutrition while participate in the preparation of plant-based meals with yours truly! Tribe Retreats was created to offer life-changing and transformative experiences that provide not only joy but give our retreaters tools that will aid them on their paths towards achieving and enjoying optimum health, wellness, and happiness.

Solare Yoga & Detox Retreats: The Italian word ‘solare’ is used to describe one who is joyful, full of life and light. Solare Detox and Yoga Retreat is designed to support you in taking a pause periodic pause from normal activity to reboot, reset, renew, and regain your light.  Our vision is to create a sanctuary to take pause from your everyday life to return to what is essential. By detoxing the on a physical, mental and energetic level you will  release the excess that is blocking the free flow of life force energy. You will reconnect to a feeling of lightness in the body, clarity of mind, and the natural state of joy and gratitude.   With Solare retreats,  you will walk away with valuable tools that will allow your inner radiance to shine.

5 day all-inclusive Detox, Yoga and Wellness retreat in Puglia, Italy

An exclusive and revitalizing five nights in one of the most breathtaking regions of Italy. The Salento peninsula in Puglia is known for its natural beauty, sun-kissed coastline, simplicity, splendor and culture.  Architectural Digest named Salento “Italy’s Under-the-Radar Treasure.” Recharge in a private natural reserve immersed in the restorative countryside of Southern Italy while overlooking the crystal waters of the Adriatic sea.

The five day retreat is guaranteed to not only detoxify the body, calm the mind and enliven the spirit- but will be filled with extraordinary moments where memories of a lifetime will be made in one of the most stunning settings in Italy.

"Somewhere in Umbria..."

Tribe Retreats goes to Eremito "Hotelito del Alma." a 4 day/3 night "digital detox retreat, all inclusive wellness, plant based nutrition and meals, yoga and excursions. Created for the solo traveler, Eremito is a mystical place located within the Umbrian valleys. The hotel is an ancient monastary transformed into a luxury eco-resort for our May 2018 retreat. Join us for three blissful nights and four days of pure holistic wellness for spiritual and physical regeneration. Eremito is “the ideal place for those who realize that peace and quiet are essential ingredients to find inner peace. It’s a mystical place, fruit of a long journey of self discovery.

Tribe retreats has joined Eremito to create a one of a kind experience of "digital" detachment from the hustle and bustle of daily lives.  A combination of nature, peace and silence encourages wellness while "The Tribe" provides daily yoga, mindfulness, plant based meals and  cooking workshops.

SOLARE yoga & Detox Retreat in eremito

Fall Detox & Yoga Retreat at Eremito. September 20th-23rd, 2018

We all possess that unique special light within. When it is allowed to shine freely, we feel alive- tuned-in, turned-on, and connected to self and others.  We are in flow with the world around us.

The Italian word ‘solare’ is used to describe one who is joyful, full of life and light. But sometimes this light is dimmed: the connection to our innermost Self is cut off by the the incessant rhythm of modern life...the constant doing, attachment to technology, busyness, and stress create veils that block our inner source of light and life-force energy. The result? Burn-out. Exhaustion of body and mind.

The remedy? Take a periodic pause from normal activity to reboot, reset, and renew. Slow down, bathe in silence and stillness, attend to the body and soul, sleep deeply. Nourish yourself with plant-based foods to detox and lighten the body. Turn off the phone, computer, television. Disconnect from the digital dependence and constant distraction. Spend time in nature and recalibrate the nervous system and biological rhythms. Get back in your body with yoga, breathing, and mindful movement. Solare Detox and Yoga Retreat is a three night retreat designed to support you in this process.


USDOT proposed budget set at $74 billion

Written by admin

U.S. Transportation Secretary Ray LaHood today praised President Obama's $74 billion budget for the U.S. Department of Transportation saying the funds will lay a new foundation for economic growth and competitiveness by investing in a national infrastructure network, building on recent safety achievements and modernizing transportation systems through research and innovation.

“President Obama’s budget for the Department of Transportation reflects our commitment to investing in an America that is built to last,” said Secretary LaHood. “A strong American economy depends on the roadways, runways and railways that move people and goods from coast to coast and around the globe. President Obama’s plan will enable us to build the American infrastructure we need for tomorrow while putting people back to work today.”

The centerpiece of the President’s FY 2013 budget for the DOT is a six-year $476 billion surface transportation reauthorization proposal that will improve America’s highways and transit networks, continue to ensure that these systems are safe and give travelers new options by enhancing and expanding passenger rail service. This proposed budget would be paid for using half the six-year savings achieved from ramping down the wars in Iraq and Afghanistan, with the other half used to pay down the national debt.

The Administration’s budgeted $2.5 billion for the first year of a six-year, $47-billion rail investment plan. This will help the Federal Railroad Administration continue to work with states as they plan and develop high-speed and intercity passenger rail corridors across the country. The Administration also hopes it will place high-speed rail on equal footing with other transportation programs, revitalize domestic rail manufacturing and ensure that the nation can reach President Obama’s goal of providing 80 percent of Americans access to high-speed rail within 25 years.

Categories: Ballast, Ties, Rail, Bridge/Retaining Walls/Tunnels, C&S, Class 1, Commuter/Regional, Intercity, Intermodal, OFF Track Maintenance, ON Track Maintenance, Rapid Transit/Light Rail, Safety/Training, Shortline/Regional, Track Machinery, Yards & Terminals


Medical questions & health advice by board certified doctors

"I have chronic acid reflux. Is there a permanent cure for this problem?"

ZocdocAnswersI have chronic acid reflux. Is there a permanent cure for this problem?

I am 31, 5'8" weighing 185 pounds. Not sure whether reducing my weight particularly around the stomach would help.

Acid reflux, or gastroesophageal reflux disease (GERD) is a common illness encountered in the primary care setting. The classic symptom of heartburn occurs as a result of the reflux of excess acid produced in the stomach up into the lower portion of the esophagus. When this occurs, irritation of the mucosal lining of the esophagus can occur, resulting in inflammation and pain. Fortunately, there are a variety of behavioral and medical interventions that are effective in treating this condition. Avoiding types of foods that provoke acid production can help, such as citrus fruits, tomato sauce, alcohol, soda and other acidic foods. As most people experience their worst symptoms in the morning (after laying flat all night), raising the head of the bed with a wedge or using an extra pillow can also be helpful. Avoiding late night meals and snacks can also help with morning symptoms. Weight loss has also been shown to be effective in curtailing symptoms. Medications known as proton pump inhibitors are very effective in reducing the production of stomach acid. These can be purchased either over-the-counter or with a prescription from your physician. These are some of the most commonly prescribed medications in this country. You should also talk to your primary care doctor about this right away. If the usual conservative measures are not working to relieve your symptoms, then a referral to a specialist (i.e. gastroenterologist) can be made.

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System Concepts for Solar Space Heating of Industrial Buildings

In most solar space heating systems applied in factory buildings, standard system concepts have been used — collectors heat a storage tank that feeds into an underfloor heating system (see Figure

Подпись: Heat Store Boiler Подпись: I §
image179 image180

Another option would be to use the thermal mass of the concrete floor of the building, which has a large storage capacity, to replace the storage tank entirely (see Figure 4). This is possible because most industrial buildings have a relatively thick concrete floor and the required room temperatures are typically lower than in residential buildings.

Figure 3. System concept with storage tank. Figure 4. Hydraulic layout without storage tank,

the concrete slab is used to store solar heat.

An additional step to simplify the system would be to abandon the heat exchanger and to fill the entire system with antifreeze fluid. The disadvantage of this concept is that a large quantity of antifreeze fluid is needed depending on the size of the building. The anti-freeze fluid is expensive and has to be replaced from time to time. On the other hand, the cost of the heat exchanger can be saved and there is no loss in temperature from the collector to the space-heating loop due to the heat exchanger.

If the concrete floor is used to store heat, it should be charged whenever there is heat available from the collectors even if the room temperature is already reached. This way, the storage capacity of the floor can be best used. Of course, both room temperature and floor temperature should not pass certain specified limits. The European standard EN 1264 states maximum floor surface temperatures of 29°C in the central part of the floor surface and 35°C in the peripheral zone. These temperatures are determined by physiological considerations.

2. Dimensioning

The dimensioning guidelines presented are based on simulations [1] of the reference buildings with different heating system concepts and system sizes (collector areas 100 — 400 m2). Weather data for Graz, Austria and a standard flat plate collector [po=0.8, c1=3.5 W/(m2K), c2=0.015 W/(m2 K)] were used. To avoid detailed simulation calculations in the pre-planning phase, generally applicable dimensioning nomograms were developed to allow a rapid and reliable estimate of the collector area and the solar storage tank volume for space heating applications in factory buildings.

Apart from the key data for the solar thermal system, the solar fraction to be expected for the project in question and the specific solar yield can be read off the nomogram. The solar fraction is defined as

Подпись: (1)Подпись: (2)Solar Fraction = 1 —

where Qaux Energy delivered by the auxiliary heating system, kWh/a

Qconv Energy needed for space heating without the solar thermal system, kWh/a

To simplify the use of nomograms, the "utilization ratio" is defined as an important auxiliary characteristic number. This is a measure for the dimensioning of solar thermal systems and describes the ratio of annual consumption to the collector area.

Annual heat requirement kWh

Utilization ratio = [ ]

total heat requirement a • m^

Gross collector area

It should be remembered that the following nomograms are only suitable for the design of solar thermal systems in factory buildings similar to the calculated reference cases and for similar boundary conditions. All cases were calculated based on the assumption that the set room temperature of 16°C has to me met at all times. If for example at night or at the weekend lower room temperatures can be tolerated, higher solar fractions are possible.

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Pink Fire Pointer Alternative Therapies to Pain Killers

Alternative Therapies to Pain Killers

For many people, the first warning of the pain of all kinds, such as headaches or migraines, muscle pain, cramps, joint pain, premenstrual symptoms and want immediate relief should reach the people, for a bottle paracetamol or pop an aspirin or ibuprofen, without thinking much.

One can opt for surgery or just pop an analgesic for short-term relief of acute or chronic pain, but also prevents the body's organs on a long term basis.

Medicine demonstrates the power of alternative therapies. They are more effective in the long term as well as medicines and are, without any negative side effects.

Herbal Therapy
Many herbalists recommend the benefits of herbs and natural compounds in the case of pain or headaches, tension or nerve pain, to pacify natural counterparts, as found in nature to help this discomfort.

Types of effectiveness of herbal analgesics include essential oils, such as jasmine, mint, juniper, rose, rosemary, which are known for their general analgesics, lavender especially for people suffering from rheumatism and common color cheap and also works as an anti-bacterial and antifungal agents.

Ginger is a powerful antioxidant herbal, which is ideal for healing skin irritations and pain associated with this condition. Other types of herbal analgesics include neem, eucalyptus, aloe vera gel, yellow dock, saffron, burdock, passionflower, kava, wood betony, wild lettuce, etc.

Simple means such as chiropractic treatments best home exercises and subacute pain. Chiropractor in Vancouver on the site and the exact cause, and if the self-regulatory body to adjust and heal. The care of the spine and nervous system maintenance is an essential part of the natural approach to health and wellness.

Therapeutic massage
Massage therapy is not only better for the body, but it's relaxing. While you relax on the table, played with soothing music and a pleasant scent, you slip into a wonderful world that is to calm the mind and body.

Without the use of medications that you can get rid of back and neck pain, muscle pain or stiffness. Sometimes, the hub of the problem instead of just treating the symptoms.

Osteopathy is the only treatment for back pain, which strives to musculoskeletal pain, sports injuries, etc. It has a positive effect on the body's nervous, circulatory and lymphatic systems treated. This therapy has brought a holistic approach to health care, and not just treating the problem, but use manual techniques to balance the body's systems to improve the overall health and well-being.

Cold therapy
Cold therapy as analgesic gel suggested by friction on a cold body to the surface of the wound. When applied immediately after an injury, it contributes to the construction of the injured tissue, and also helps to reduce the swelling of tissues. When the application took place long after the injury, freezing ice acts as an analgesic, an analgesic agent. Cold therapy or ice therapy is an effective way to get relief from joint pain.

Come analgesic effect can not come increasingly providing flow natural painkillers, but by improving the ability of these chemicals in a brain cell and exert their analgesic effect.

The conclusion of all this is that the pain of any kind can largely by the habits of daily exercise to ensure benefits for your body and mind, and alternative therapies are clearly better avoid long term.


Illinois, Indiana, Ohio, Missouri

The Illinois, Indiana, Ohio, and Missouri Departments of Transportation

The Missouri, Illinois, Indiana and Ohio Transportation Departments formed a coalition to investigate the feasibility of adding dedicated truck lanes to I-70 through their 165-mile-long, four-state corridor.

As a subconsultant, Lochmueller Group (Lochgroup) provided specialized planning and environmental services to support the traffic and revenue forecasts, economic impact analysis, and environmental screening of the alternatives. Lochgroup’s responsibilities included:

Lochgroup’s analyses synthesized data from many sources including multiple statewide and MPO travel models, the National Household Travel Survey, GIS databases, and numerous analyses and reports in order to develop the best possible assumptions for the I-70 corridor.

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Mutemelodist. –

21 Jan

Comparative Literature: Retrospect and Prospect_B.K.Das

         Comparative Literature: Retrospect and Prospect - B.K.Das

What are source and target languages?

A translator while undertaking the task of translation deals with two languages – the Source Language (SL) and the Target Language (TL). The translator renders the Source Language text into the Target Language text.

Discuss the various definitions of Comparative Literature

The simple way to define Comparative Literature is to say that it is a comparison between two literatures and does not have an independent status. It analyses the similarities and dissimilarities and parallels between two literatures. It further studies themes, modes, conventions and the use of folk tales and myths in two or more different literatures.

“Comparative Literature is the study of literature beyond the confines of one particular country, and the study of the relationships between literature on one hand and other areas of knowledge and belief, such as the arts, philosophy, history, the social sciences, the sciences, religion, etc. on the other. In brief it is the comparison of one literature with another or others, and the comparison of literature with other spheres of human expression.” Henry RemakComparative Literature: Method and Perspective (1961).

            “Comparative literature juxtaposes literary texts from different languages and cultures. It connects, say, a poem with dance, a film with the novel, photography with the essay.” Sandra Bermann

“First, Comparative Literature means the knowledge of more than one national language and literature, and/or it means the knowledge and application of other disciplines in and for the study of literature and second, Comparative Literature has an ideology of inclusion of the Other, say, a marginal literature.” Steven Tötösy de Zepetnek, Comparative Literature: Theory, Method, Application (1998).

Discuss the different senses in which Wellek and Warren used the term Comparative Literature.

Wellek and Warren have used the term comparative literature in three different senses.

The first sense is the interaction between oral literature and written literature of a particular culture or country. This interaction can be studied profitably by comparison. To Wellek and Warren, the term comparative literature may mean “the study of oral literature, especially of folk tale themes and their migration: of how and when they have entered ‘higher’, ‘artistic’ ‘literature’. Oral literature is an integral part of culture and literary scholarship and thus, should be read along with written literature.

The second sense is the study of relationships between two or more literatures. However, it is not always easy to distinguish one literature from another. The general notion is that a literature is usually known by the language in which it is written. In the post-colonial period we find that several literatures are written in the same language. For example, English literature, American literature, Canadian literature, Caribbean literature, Australian literature and Indian English literature are all written in English language.

The third sense is by identifying comparative literature with world literature. The concept of World literature comes from Goethe’s Weltliteratur, which means all literature should be studied and taken as one. The conception of World literature is utopian in nature. Some comparatists have advocated that all the literary masterpieces should be taken as one and read in comparison.

How does Wellek and Warren theorize literary influence?

Page 37 first paragraph.

How does literary influence work in the Indian context?

British Romantic Poetry has been hailed in India for its revolutionary, liberating character and sentimental appeal. Madhusudan Pati points out that Wordsworth rather than Byron became the major source of inspiration. Certain aspects of Romantic poetry were particularly stimulating and gratifying to the Indian poets. In the Indian context we can make a two-fold approach to Comparative Literature: one, the influence of European writers on our writers and vice versa, and second, the influence of Indian writers of one region on the other Indian writers of another region. In the first category we may include Eliot’s influence on our poets and Indian influences on Eliot, Whitman and so on. In the second category we may include Premchand’s, Bankim Chandra’s, Tagore’s influence on Fakir Mohan Senapati and so on.

What are the recent trends in Comparative Literature?

In the 20th century there is a rise in interest in the study of comparative literature all over the world – particularly in the countries where multilingual situation prevails. In Canada there is a remarkable growth of Comparative Literature which involves the two main literatures of the country – English and French. The Canadian Comparative Literature Association founded the journal called the Canadian Review of Comparative Literature that contributes richly to the growth of Comparative Literature. In Australia, leading comparatists like David Myers and a few others of Queensland University have done commendable job in the field of Comparative Literature. In India, leading comparatists like K.M. George, Amiya Dev, Sisir Kumar Das, K. Chellappan, R.S. Pathak, Chandra Mohan and a few others have done excellent work in the field of Comparative Literature.

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Hundreds of drivers were collared by the long arm of the law during a day of police action.

On June 5 Essex Police stationed themselves in Waltham Abbey.

Over the course of the day they arrested two drivers on suspicion of drug driving and took the details of one disqualified driver.

A total of 178 people were called out for not wearing a seatbelt, with a further 39 on their phones.

Take our anonymous poll below.

Four drivers were found without insurance, three without a proper licence and four had no MOT on their vehicles.

By the end of the day, four vehicles had been seized.

Officers also watched the roads in Tilbury, Stansted, Southend and Colchester.

In the five areas 570 people were caught without seatbelts and nearly 100 on their phones.

An elderly man also had his licence revoked after failing an eye test.


Privacy and data policy

Website administered by Copenhagen Capacity

When you register contact information and submit an application and a CV in our database, it will be recorded and stored on our system system as long as we have a real, substantive purpose with this. Personal information is kept for the sake of being able to show a talent pool of highly qualified foreign candidates to companies in Greater Copenhagen that are searching for specific types of candidates and skills.

This information will not be shared with third parties except as necessary to carry out our business or if we are required to do so by law or due to a court order, or if it is transmitted in the event of any attacks on Copenhagen Capacity’s Internet infrastructure.

To this end may at times deposit certain pieces of information called 'cookies' on a visitor's computer. These 'cookies' allow a more detailed level of tracking to fine tune our usage reports. However should you have disabled or blocked 'cookies' on your machine then you continue to have exactly the same access to the website content as with 'cookies' enabled, it will only result in slightly less accurate usage figures for our own internal reports.

Disclosure of personal data to third parties

Any data that has been recorded during your visit to’s website may be shared with the Greater Copenhagen collaboration's official partners. Partners involved in specific campaigns will be allowed to use data collected through the campaign.

Contacting Copenhagen Capacity


Read my musings on human nature, astrology, and more...

Waiting for the knife to drop

Waiting for the knife to drop

Today is a new moon AND a total solar eclipse in the sign of Virgo. New moons are fresh starts, when Sol and Luna kiss in the sky a seed is planted that expresses the themes of that sign. Virgo, one of the most consistently misunderstood signs of the zodiac, presides over the harvest after the fullness of summer. Hard work, sorting, analyzing, serving, cultivating health, daily ritual, and mentoring are all activities belonging to the season of Virgo.

Symbolized by the Virgin (originally meaning one who is whole unto herself) and ruled by the quick-moving and mental planet Mercury, Virgo seeks to create a purified, healthy vessel for the blossoming of the mind and spirit. Opposite to watery Pisces, the last sign along the zodiac wheel, Virgo involves the intelligence required to make it through the world of matter. Virgo seeks to perfect, to express spirit through each detail of living, to make the sacred alive through the mundane.

Virgo desires to share herself so fully, so completely, and to be a totally willing vessel for the mystical; these characteristics are gravely misunderstood in an era that champions exploitation of the earth and denigration of the female body.

Virgo can give and give and give without depleting so long she is taken with grace and gratitude. When she feels depleted and misunderstood, she closes and criticizes, contorting into the narrowed stereotypes that we’ve come to key-word Virgo with, nit-picky and tight-assed!

With so much action in Virgo (Sol, Luna, Luna’s nodes, Jupiter, and retrograde Mercury), we are urged to lovingly and humbly work toward self-mastery - may each action and word be in service to divinity here on Earth.

Humility and quiet dedication are not easy modes to access in a sky like this as Mars and Saturn, the two extreme planets, very hot and very dry respectively, are currently paired up in the seeking sign of Sagittarius. Saturn with Mars demands that our sexual energies be disciplined and that our actions be based on sound, sober judgment. Righteousness and bold anger is the shadow side of this pairing.

Mars and Saturn must answer to Jupiter, meaning that our actions and social structures should be founded on faith and wisdom, but Jupiter must answer to Mercury. Jupiter is the guru and Mercury is the eternal student - what happens when Jupiter becomes student to Mercury?

A highly respected teacher of yours, who you tend to place upon a grand pedestal, visits your home after a long, arduous journey, a journey that starkly contrasts with your teacher’s regular adventures and spiritual questing. Of course, you welcome your teacher to your home, eager to be host this inspiring presence and happy to be the comfortable, knowledgeable one for a change.

Your teacher is very tired and humbled, a state rather unfamiliar to you. Overwhelmed with the new teachings and difficult experiences accumulated, your teacher is grateful to receive your keen insights and welcoming presence so they can sift, organize, and integrate the new teachings.

At night when your beloved teacher rests, you tiptoe into the basement of your home to process the stories of their journey into service.

  • What do you find?
  • What can you teach your teacher?

Whatever it might be, make sure it is practical (Virgo), founded on real, lived experience (Saturn in Sagittarius), compassionate (Neptune in Pisces), and prompting of action (Mars in Sagittarius). Gather the information and discern what is most compelling, what is most urgent.

A sky like this leaves an imprint that lasts at least 6 months so do not fall into an endless spiral of criticism which is easy enough with the strong Virgo signature. Be honest with what could be better and be ruthless in mastering yourself and your work but stay soft and yielding to the world around you too. The Virgin is the earthly alchemist, sorting wheat from the chaff, and cultivating a temple worthy of the Divine current.

***blog art by Henry Asencio***

New Moon in Libra: Working For Our Miracle

New Moon in Libra: Working For Our Miracle

Extreme Female Brains, the Issue of Nature vs. Nurture, and the Emergence of Capitalism


Differential effects of doping.

by Andreas Baumann

Recently, Danish cyclist Michael Rasmussen admitted to using performance-enhancing drugs (PEDs) for more than ten years (nb: link in Danish).

Naturally, this led to public debate about the use of PEDs. However, I think one point needs to be adressed: the fact that the use of PEDs have different effects for elite sportsmen and ordinary people. Since one of the arguments against the use of PEDs within elite sports are the negative consequences for ordinary people, I believe that one should ponder this point.

Performance-enhancing drugs, when used by elite sportsmen, have very few to zero negative effects. Think about it: when did you last hear about a cyclist who died from the negative health effects of, say, EPO? There was a “massacre period” from the late 80s, culminating in the Affaire Festina (1998), but for the last 10-15 years we haven’t really seen any negative effects of the doping practices. On the other hand, we see the positive effects of the use of PEDs in every sporting competition: no man, driven alone by his spirits and desire to conquer, could race the Tour in a style similar to that of the great cyclists. Their cycling gives us pleasure, it allows us to marvel at the great performances. Those are the positive effects (externalities) of professional use of PEDs.

However, there are large negative effects of PED use outside professional sports: adverse health effects, due to the lack of qualified doctors treating complications relating to use of PEDs. In a system of socialised medicine (as most industrialised countries employ) this is an externality, since the people paying for the eventual treatment cost will not be the ones who have benefitted from the use of doping. Another negative externality from non-professional use of PEDs is the altered behaviour of users, particularly evident in users of anabolic steroids, who are prone to bouts of aggression and violence (CNS Drugs 2005).

Summing up, doping in professional sports mostly has positive externalities, while doping outside the realm of professional sports has negative externalities. Clearly, the logical conclusion should be that while the use of PEDs should be legalised (or at least decriminalised) within professional sports, it should still be illegal outside this field. But how do we reconcile this with our respect for the universality of law?
Many things, which are illegal outside of sports, are legal within this realm: boxing, to take one example. Maybe we ought to recognize that some of the regulations of drugs is subject to the same discretion.


Egypt dominated the history and culture of North Africa and the Middle East for millennia. By the eighth century B.C., however, Egyptian strength had waned, opening up possibilities for new powers. One such rising power was in the region the Egyptians called Nubia, in what is today the Sudan. Kush, sometimes known as Cush, was an important center of trade in the region. Its location, resources and social structure contributed to the kingdom's success in trade.

Location, Location, Location

Kush’s location was ideal for trade. The Nile River provided a route to Egypt and the rich ports of the Mediterranean Sea. In the east, Kush had access to the Red Sea, opening up trade to the Arabian peninsula, the southern east coast of Africa and ports even farther away. With mountains to the south and desert to the west, these water routes proved invaluable for Kush’s trade.

Elephants and Iron

Among the resources that Kush traded were elephants, rare outside of the region, and iron, which the Kushites likely learned to work from the Assyrians, according to Steve Sofferan and Sarah Wood Purdue University. Less directly influential but still important to trade was the stable government of the kingdom. Sofferan and Wood describe the state as “slightly less autocratic” than that of Egypt, and more decentralized. The stability of the Kushite government allowed the state to weather incursions by Rome in the north and to survive a move of the capital from Napata to Meroe.


If person keeps a fast on 10th Of Muharram and due to some inconvienience and difficulties while fasting he ignores Sawm of 11th Muharram. What is the Sharee’ah ruling. Jazak Allah.

Respected Brother-in-Islam

Assalaamu Alaykum Wa Rahmatullaahi Wa Barakaatuhu

The purpose of fasting a day before or after the 10th Muharram is to avoid
imitating the Jews who fast only on the 10th of Muharram. If one is unable
to keep the second fast due to circumstances, he will be excused.

and Allah Ta’ala Knows Best

Mufti Ebrahim Desai


RAWALPINDI - Police bashing is an old fashion as the people blame it even for the wrong doings of others but ignore that there are many black sheep in City District Government Rawalpindi (CDGR) and Islamabad Electricity Supply Company (IESCO) too.
During the recent campaign to unveil the electricity and gas thieves as directed by PML-N-led federal government, the CDGR officials in connivance with IESCO's corrupt officials have hanged so many innocent citizens with the hook, including small shopkeepers and traders by lodging FIRs on account of electricity or gas theft in almost all the police stations thus overlooking the big fishes involved in heinous crime of electricity and gas theft.
Moreover, the representatives of WAPDA Hyrdo Electric Workers Union (CBA) jumped into arena and staging protests against the honest and competent police officers to save the skinks of the most corrupt and incompetent XENs, SDOs, line mans, assistant line mans and meter readers, who implicate the innocent citizens in fake cases but sparing those who fill their pockets with money. This was done to mold the inquiry of the cases.
It also happened on Monday, when tens of hundreds of WAPDA workers union, led by their union leader Javed Baloch, agitated against two police officers for calling their six ASLs and meter readers in police stations for questioning as to why they implicated innocent citizens in theft cases.
The protestors chanted slogans against police and demanded immediate suspension of the two police officers- Station House Officer (SHO) Police Station (PS) Saddar Bairooni Jahangir Bhatti and SHO PS Naseerabad Chaudhry Jamil-for harassing the WAPDA officials. Sensing the sensitivity of the matter, Magistrate Kamran Khan, SP Headquarters Muhammad Masud Raza and ASP Haroon rushed to the scene, negotiated with the protestors and managed to disperse them. During the entire episode, the commuters and pedestrians faced hardships.
Both the SHOs, while talking to The Nation, rebuffed the allegations of harassment of officials, saying they called them just for probing.
They said that WAPDA officials wrongly implicating the innocent citizens in electricity theft cases while not exposing the high and might electricity and gas thieves.
Chaudhry Jamil, SHO Naseerabad, told the task force got registered a case against one Nadeem, the owner of Falcon Bakery at Misrial Road, of stealing electricity but police found him non-guilty after through investigation. "I ask the applicant line man of WAPDA to come police station and take part in investigation. Neither I lock him up nor I torture him", SHO added.
Same said by SHO Jahangir Bhatti that police found no evidences of electricity theft against Bahadur son of Allah Dad, a pump owner at Adyala Road, Muhammad Ishaq, owner of a plastic factory at Adyala. WAPDA line mans accused both of them of stealing electricity by slowing down their meters. "When the laboratory tests of WAPDA meters were conducted, it proved that they are not tempered and he invited IESCO officials in police station to ask as to why they lodging wrong FIR against the innocent citizens" Jahangir said.
He said that they not only refused to come to police station but also staged a protest demonstration at main artery of the city just to pressurize SHO to wind up the case for lodging wrong FIR against the citizens.
Similarly, Nadeem, a resident of Liaquat Colony facing charges of converting domestic meter to commercial meter, proved innocent in police investigation, SHO added.
Commissioner Rawalpindi Division, District Coordination Officer (DCO) and Javed Baloch, the WAPDA union representative, did not attend their phones calls when contacted by this scribe to know their versions about the issue.


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A survey on sleep assessment methods

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Subjective methods present a sensitivity between 73% and 97.7%, with specificity 50%–96%. Objective methods such as actigraphy present a sensibility higher than 90%. However, their specificity is low being one of the limitations. https://t.co/lRCKXWTuaO https://t.co/hFRfJbVt8p
A survey on sleep assessment methods https://t.co/bdo9EJ6wEV https://t.co/h6s2zkqF6d

Sleep is fundamental to health. Sleep disorders can often be a symptom of a disease; or also may be an indicator of a future disease such as depression. For those reasons, sleep assessment is an essential component of any health check. As such, many health care systems stablish mechanisms to prevent sleep disorders by providing specific plans in relation to education and awareness of good sleep habits.

Over the years, many different sleep assessment methods have appeared. Specially in the last years, new methods have emerged with the appearance of new technologies such as mobile apps and novel advanced hardware sensors such as galvanic skin response measurers. In this survey, we review the current methods for the detection of sleep. From simple methods that only distinguish between awake or asleep states to complex methods able to distinguish all the sleep stages; from subjective methods such as sleep questionnaires and sleep diaries to objective methods such as polysomnography.

The main motivation of this survey is to produce a comprehensive and unbiased literature review from which we can extract a complete classification of sleep assessment methods (including new technologies such as mobile apps). There have in the past been different reviews of sleep assessment methods, but most of them are outdated (see, e.g., Lomeli et al., 2008; Kelly, Strecker & Bianchi, 2012; Winter, 2014), or they are partial, or only focus on a specific subset of methods (e.g., sleep questionnaires: Silva et al., 2011; Firat et al., 2012; El-Sayed, 2012; Pataka et al., 2014; Singh & Mims, 2015; Chai-Coetzer et al., 2015, mobile apps: Lee & Finkelstein, 2015; Ong & Gillespie, 2016, or contact sleep detection methods: Kolla, Mansukhani & Mansukhani, 2016; Maslakovic, 2017; Green, 2017, etc.).

The survey was written to appeal to a range of people, who would have a broad spectrum of interests. It covers all sleep detection methods and, for each method, it also provides a table with the most used market products. Hence, because the survey tackles different technical areas, all technical terms have been conveniently introduced and explained. In all cases, explanations are supported and complemented with adequate references. Of course, not all sleep detection methods have the same precision; in fact, some of them are completely subjective. Therefore, the comparison of methods deserves a critical view on validation. Thus, we also report on the reliability and validity of the methods analyzing previous comparisons and validation studies.

Survey methodology

The literature review begins with a planning phase. This phase formulates research questions and defines inclusion and exclusion criteria. This phase is followed by search and screening of primary studies.

Research questions

We formulated two research questions to identify the current state of the art in sleep assessment methods:

  • What methods for sleep assessment have been developed?

    This research question aims to provide an overview of the sleep assessment methods, with special emphasis on those that have been developed over the last 10 years.

  • What are the main characteristics of each sleep assessment method?

    This question complements the previous one, giving a deeper understanding of the sleep assessment methods.

Search process

The purpose of a literature review is to conduct a review of relevant studies to assess the body of knowledge that exists to support addressing the research questions. This process is rigorous and unbiased, and it involves a wide coverage of sources, such as online databases, journals, and conferences. The search string created to retrieve information from the electronic resources and databases is the following:

(assessment OR evaluation OR detection)
AND (method OR tool OR environment OR system)
AND (sleep)

This search string was designed after an analysis of the keywords from the relevant literature, which was found from several general searches in the resources outlined above.

With the search terms defined, we started the process of identifying relevant literature in the following electronic databases: PubMed, LILACS, TOXNET, SCOPUS, ScienceDirect, and Google Scholar. Initially, we sought potential primary studies in the databases. In PubMed Health, the search string produced 1,784 results. Therefore, we had to filter the results by refining the search string for that database:

“sleep detection”[Title/Abstract] OR “sleep assessment”[Title/Abstract]

As a result of the search process, 318 studies were identified. Excluding unavailable and duplicated results, we obtained 212 studies.

Inclusion and exclusion criteria

To address the research questions, the following inclusion and exclusion criteria were defined:

  • IC1: Those papers that discussed sleep assessment methods were included.

  • IC2: Those papers that described the characteristics of a sleep assessment method were included.

  • EC1: Those papers that did not describe a sleep assessment method were excluded.

Studies selection

Initially, we performed screening on the titles and abstracts to decide whether to include or exclude each study. As a result, from the six sources that we searched, a total of 114 studies were selected and 98 were excluded. We read in detail the full text of each primary study included in the preliminary selection to decide whether to include or exclude the study. The primary studies included in the final selection correspond to the relevant papers that meet the research questions set out in this study. The QUOROM flow chart of the reviewing process is depicted in Fig. 1.

QUOROM flow chart of the reviewing process.
Figure 1: QUOROM flow chart of the reviewing process.
Solid arrows represent the QUOROM flow. Dashed arrows represent the decomposition of a box into several sub-boxes.

Data extraction

With the final set of primary studies decided upon, the data extraction activity was carried out on included papers. For each paper, we identified the kind of article (review, opinion, study, tool description …) and the sleep assessment methods it described. We grouped the data by sleep assessment methods and identified a total of five categories where all sleep assessment methods can be classified (see ‘Classification of Sleep Detection Methods’). For each method, a single document was produced, grouping the data coming from all papers related to the tool. This produced summaries and charts that helped us to study and classify the methods.

Structure of the survey

The rest of the paper has been structured as follows: in ‘Classification of Sleep Detection Methods’, a classification of sleep detection methods is proposed. Then, in ‘Medical Assistance Methods’, those methods that need medical assistance are explained. Similarly, those methods that do not necessarily need medical assistance (self-assessment methods) are explained in ‘Self-Assessment Methods’. In ‘A Critical Discussion About Accuracy and Validation’, we discuss the accuracy and validity of the methods presented. We also discuss the usefulness of some of the methods, and we comment on future developments. Finally, in ‘Conclusions’ we provide a concluding summary.

Classification of Sleep Detection Methods

Essentially, a sleep detection method is a function that classifies the sleep state of a patient. Most sleep detection methods such as wrist actigraphy or mobile apps consider a binary function, where the state can be classified as Awake/Sleep. More sophisticated methods consider a ternary function: Awake/NREM/REM. And, finally, the most advanced methods, such as polysomnography—often used as the gold standard—consider a quinquenary function: Awake/N1/N2/N3/REM. Hence, any method can produce a two-dimensional chart where the X-axis is Time, and the Y-axis is the State of the Patient. In the particular case of polysomnography, the Y-axis has five possible values; thus, it can determine the sleep stage of the patient at any time, and study the transitions occurring between the states. Of course, a sleep study such as a polysomnography often produces much more complementary information that can be used, e.g., to diagnose sleep diseases. Among the information reported by a polysomnography we find oxygen saturations, limb movements, apneas, respiratory events by body position, etc. The interested reader is referred to Robertson, Marshall & Carno (2014), Pandi-Perumal, Spence & BaHammam (2014) and Armon et al. (2016) for information about sleep study reports and their interpretation and usage.

The information that is common to the majority of sleep detection methods is the one that refers to a binary state classification (i.e., Awake/Sleep), because this is achieved by the basic methods, and subsumed by the advanced methods. Table 1 defines the basic parameters that can be collected by a binary state classification method. In grey, we show the primary data that should be collected by the sleep detection device and, in white, we show the most important parameters that can be derived from the primary data.

Table 1:
Definition of basic sleep detection parameters.
This table summarizes the main parameters of a sleep study. The top of the table (light blue) lists the fundamental parameters. Those parameters that can be derived from the primitive variables are listed in the dark blue rows. Each of them includes its associated formula.
Sleep measure Definition Formula
Fundamental parameters
Initial In Bed Time (IIB) Time when patient goes to bed initially
Final Out Bed Time (FOB) Time when patient leaves the bed definitely
Time Out of Bed (TOB) Total time out of bed between IIB and FOB
Lights Out Time (LT) Time of lights out
Lights On Time (LN) Time of lights on
Sleep Onset (SO) Time when first sleep starts
Final Sleep (FS) Time when last sleep finishes
Sleep Latency (SL) Time taken to fall sleep (at any time)
Sleep Period (SP) Time spent sleeping between two awakenings/SO
Awake Period (AWP) Time spent awake between two sleep periods (awakening=wake period >10 s)
Arouse Period (ARP) Time spent awake between two sleep periods (arousal=wake period <10 s)
Derived parameters
In Bed Time (IBT) Total time in bed IBT = FOB-IIB-TOB
Total Recording Time (TRT) Time between lights out and lights on TRT = LN-LT
Initial Sleep Latency (ISL) Time taken to fall sleep the first time ISL = SO-LT
Total Sleep Time (TST) Amount of time the patient sleeps during TRT TST = i = 1 i = N # s l e e p p e r i o d s S P i
Sleep Interval (SI) Time between the first sleep and the last sleep SI = FS-SO
Wake After Sleep Onset (WASO) Wake time between IIB and FOB WASO = SI-TST
Total Wake Time (TWT) All wake time throughout TRT TWT = ISL +WASO
Mean Sleep Latency (MSL) Arithmetic average of sleep latencies MSL = i = 1 i = N # s l e e p l a t e n c i e s S L i N
Sleep Efficiency (SE) Percentage of sleep of the total time in bed SE = (TST/TRT) ×100
Mean Awakening Length (MAL) Arithmetic average of awake periods MAL = i = 1 i = N # a w a k e p e r i o d s A W P i N
Awakening Index (AWI) Number of awakenings per unit of time AWI = #AWP/TST
Arousal Index (ARI) Number of arousals per unit of time ARI = #ARP/TST
DOI: 10.7717/peerj.4849/table-1

These parameters are particularly useful to determine the kind of sleep of patients, and each single parameter is relevant for a different sleep disorder or disease. For instance, the sleep onset, sleep latency, and total sleep time are essential to diagnose patients with insomnia. Similarly, an excess in the awakening and arousal indices suggests increased sleep fragmentation. In addition to the number of sleep states that they are able to detect, a sleep detection method can be classified according to other functional and operational characteristics, such as their underlying technology, which in turn directly affects their precision and validity.

In Fig. 2, we present a taxonomy of sleep detection methods. They all can be classified into two main groups according to whether they need medical assistance (Medical Assistance) or not (Self-Assessment). In this respect, there are methods that have been classified as not requiring medical assistance, such as Questionnaires and Sleep Diaries, even though their interpretation should be normally done by a professional. However, in the current state of the art there are many systems such as mobile apps that provide custom sleep questionnaires and produce reports without medical assistance. Hence, they are classified as Self-Assessment. They both deserve a deep discussion and will be explained separately in ‘Medical Assistance Methods’ and ‘Self-Assessment Methods’, respectively.

Taxonomy of sleep detection methods.

Figure 2: Taxonomy of sleep detection methods.

Grey boxes represent categories. White boxes represent sleep assessment methods or technology used to assess sleep.

Self-Assessment methods include subjective methods such as questionnaires and sleep diaries (the figure lists some instances), and objective methods based on hardware sensors, which in turn can be classified as Contact devices or Contactless devices, depending on whether they need to be in contact with the patient’s body during sleep. Those devices that are based on the echo produced by signals can be further classified into Sonar, Radar, and Lidar devices. All of them will be explained in a dedicated section.

Medical Assistance Methods

There are different studies that can be performed in a sleep laboratory. All of them have one significant advantage and one significant disadvantage that differentiate them from the home detection methods. The obvious advantage is that these methods can use advanced technology such as electroencephalograms, electrocardiograms, etc. that cannot be used at home. The advantage of these methods is that they can be extremely precise, and can be discrete (e.g., are able to distinguish between sleep phases). For this reason, these methods have been often used as the gold standard for sleep evaluation (see, e.g., Silva et al., 2011; Firat et al., 2012; El-Sayed, 2012; Luo et al., 2014; Chai-Coetzer et al., 2015; Silva et al., 2016). Of course, the use of this exclusive technology comes with a cost: these methods are expensive, time-consuming, require professional assistance and, often, they can only be done for a reduced period of time (e.g., one or two days). But, additionally, there is another important functional disadvantage: the assessment made by these methods is done in a context that is not the usual sleep context of the patient (i.e., a sleep clinic or a hospital) and, thus, a normal sleep situation is not measured.

Polysomnogram (PSG)

The term polysomnogram comes from the Greek root poly (many), the Latin noun somnus (sleep), and the Greek verb noun gramma (drawing or diagram). A PSG (Robertson, Marshall & Carno, 2014; Pandi-Perumal, Spence & BaHammam, 2014; Armon et al., 2016) is a medical procedure composed of several concurrent but independent tests that monitor different body functions during sleep and that are recorded for their later study using different channels. An exhaustive list of tests and information gathered in a modern PSG follows:

  • Electroencephalogram (EEG)—measures and records the brainwave activity to identify sleep stages and detect seizure activity.

  • Electrooculogram (EOG)—records eye movements. These movements are important for identifying the different sleep stages, especially the REM stage.

  • Electromyogram (EMG)—records muscle activity (e.g., teeth grinding and face twitches; but also, limb movements using surface EMG monitoring of limb muscles, periodic or other). Chin EMG is necessary to differentiate REM from wakefulness, limb EMG can identify periodic limb movements during sleep (PLMS).

  • Electrocardiogram (EKG)—records the heart rate and rhythm.

  • Pulse oximetry—monitors the oxygen saturation (SO2).

  • Respiratory monitor—measures the respiratory effort (thoracic and abdominal). It can be of several types, including impedance, inductance, strain gauges, etc.

  • Capnography—measures and graphically displays the inhaled and exhaled CO2 concentrations at the airway opening.

  • Transcutaneous monitors—measure the diffusion of O2 and CO2 through the skin.

  • Microphone—continuously records the snoring volume and kind.

  • Video camera—continuously records video. It is useful to identify the body motion and position.

  • Thermometer—records the core body temperature and its changes.

  • Light intensity tolerance test—determines the influence of light intensity on sleep.

  • Nocturnal penile tumescence test—is used to identify physiological erectile dysfunctions.

  • Esophageal tests—includes pressure manometry, to measure pleural pressure; esophageal manometry to assess peristalsis, and esophageal pH monitoring (acidity test).

  • Nasal and oral airflow sensor—records the airflow and the breathing rate.

  • Gastroesophageal monitor—is used to detect Gastroesophageal Reflux Disease (GERD).

  • Blood pressure monitor—measures the blood pressure and its changes.

Depending on the particular sleep study that needs to be performed, only some specific tests from the above list are generally selected—and they are also parameterized for each specific case. For instance, the EEG is usually comprised of 10–16 electrodes, but in patients with epilepsy, often 20 electrodes are used. Similarly, to assess bruxism, the EMG electrodes can be placed over the masseter muscle, but to assess other sleep disorders, the EMG electrodes are placed in other muscle groups. For example, the intercostal EMG is used to measure the effort during respiration.

Nowadays, the PSG is the most advanced tool for the diagnosis of many sleep disorders. According to Pandi-Perumal, Spence & BaHammam (2014) and Armon et al. (2016), the main disorders that a PSG can evaluate are those in Fig. 3 (they are classified following the International Classification of Sleep Disorders (Sateia, 2014)), being especially frequent: (i) sleep apnea or another sleep-related breathing disorder, (ii) periodic limb movement disorder, (iii) narcolepsy, (iv) REM sleep behavior disorder, (v) unusual behaviors during sleep, and (vi) unexplained chronic insomnia.

Classification of the main disorders evaluated with a polysomnography.

Figure 3: Classification of the main disorders evaluated with a polysomnography.

The main disorders evaluated with a polysomnogram are structured with a three-levels taxonomy that follows the International Classification of Sleep Disorders.

Multiple sleep latency test (MSLT)

This sleep study (Carskadon, 1986; Sullivan & Kushida, 2008) is a test to identify excessive daytime sleepiness (i.e., feeling sleepy in a situation where one should be awake and alert, e.g., driving a truck) and determines how long it takes the patient to fall asleep. It also identifies the phases of the sleep (e.g., how quickly and how often the patient enters REM sleep). MSLT is the standard test to diagnose idiopathic hypersomnia and narcolepsy, and it measures how quickly a patient falls asleep during the day in a quiet environment. An MSLT often starts the morning following a PSG and it lasts one complete day. The patient tries to sleep in five scheduled naps separated by two-hour breaks. For this reason, this test is often called a “nap study”.

Each nap trial takes place in a quiet bedroom. The patient is connected with sensors to a device that can detect sleep stages. The standard procedure often includes an EEG, EOG, EMG, and EKG (Carskadon, 1986). The equipment is composed of different electrodes and monitors:

  • Wires with small cup electrodes attached to the scalp with a conductive paste to measure brain activity (EEG). This detects in what stage of sleep is the patient.

  • Wire electrodes that are taped to the face near the eyes (EOG) and chin to show muscle activity (EMG).

  • Two elastic belts around the chest and stomach to measure breathing effort.

  • A nasal cannula and small heat monitor to measure all breathing activity.

  • A monitor taped to a finger to detect oxygen levels.

  • Two to three lead EKG monitors to show heart rate and rhythm.

  • A small microphone applied to the throat to detect snoring.

Hence, the MSLT can identify exactly when the patient falls asleep, and whether or not they entered REM sleep. If the patient falls asleep, they are awakened after 15 min. The nap trial also ends if the patient does not fall asleep within 20 min. Patients with narcolepsy often have two or more REM periods during the MSLT. People with idiopathic hypersomnia fall asleep easily but do not reach REM sleep during the nap trial.

Maintenance of wakefulness test (MWT)

This test (Banks et al., 2004; Meira et al., 2017) is performed over a whole day. Contrary to a PSG, this test is made while the patient is awake. Essentially, it challenges patients to attempt to stay awake during periodic tests. Therefore, an MWT may be helpful in the management of sleepy patients, particularly for driving purposes. It measures how alert a patient is during the day and it determines whether a patient is able to stay awake for a period of time in a quiet and relaxing environment. During the test, there are four to five periods of around 40 min each, spaced apart by 2 h, where the patient is asked to stay relaxed in a quiet, faintly-lit bedroom. The first trial often begins 1.5 to 3 h after the patient’s normal wake-up time. The patient eats breakfast one hour prior to the first relaxing period and they have lunch after the second period. Between the periods, the patient can read the newspaper, watch TV, have a meal, or move freely inside the building, but they cannot go outside because daylight is a factor that must be eliminated during the test.

During the relaxing periods, patients are connected to a set of leads that monitor (i) heart activity with two to three ECG leads, (ii) brain activity with 4 EEG leads, (iii) chin muscle activity with three leads, and (iv) left and right eye movements. If the patient falls asleep for 90 s at any time during the relaxing period, the test is terminated. All data collected are analyzed by a sleep specialist to determine the patient’s level of sleepiness during the day.

CPAP titration test (CTT)

A CTT (Lopez-Campos et al., 2007) is a type of sleep study that is used to calibrate continuous positive airway pressure (CPAP) and bi-level positive airway pressure (BIPAP) therapies. CPAP/BIPAP are the common treatments in some sleep-related respiratory disorders (see Fig. 3) such as central sleep apnea (BIPAP) and obstructive sleep apnea (CPAP), which eliminate breathing pauses during sleep. Before starting these treatments, a CTT is needed.

The objective of a CTT is to determine the amount of air pressure needed to prevent the upper airway from becoming blocked. This is studied during the sleep of the patient with a nasal mask that periodically changes the air pressure, and different sensors that monitor the sleep in a similar way to a PSG (i.e., they record oxygen levels, breathing, heart rate, brain waves, and leg and arm movements).

Home sleep test (HST)

The HST (Cruz, Littner & Zeidler, 2014; Kapoor & Greenough, 2015) is a kind of limited PSG that is made at home (i.e., portable equipment is transported to the patient’s home). The number of channels used is often reduced to three: airflow, respiratory effort, and oximetry. It provides an indication only for high suspicion of obstructive sleep apnea—not other sleep disorders—and it has the obvious advantage that the context in which the sleep is evaluated is the normal one. The main disadvantages are that it cannot determine sleep stage, hypopneas, or arousals; and no one is present to replace leads.

Self-Assessment Methods

Sleep questionnaires

The preliminary evaluation of sleep in primary care is often completed with a sleep questionnaire (also known as a sleep scale). Sleep questionnaires are a very inexpensive and rapid test, and for these reasons, they are ideal for the first diagnostic test. Moreover, they summarize in a quantitative way the (subjective) perception of the patient about his or her own quality of sleep. Precisely because they are mostly subjective, sleep questionnaires can be influenced by the same sources of bias and inaccuracy as any other such reports. However, their subjectivity does not necessarily render questionnaires inaccurate, as it has been demonstrated by several validation studies (see Silva et al., 2011; El-Sayed, 2012; Firat et al., 2012; Luo et al., 2014; Pataka et al., 2014; Chai-Coetzer et al., 2015).

In general, filling in a sleep questionnaire does not require the assistance of sanitary professionals. They can be self-administered at any moment, even at home. For instance, the Google play’s Sleep Apnea Screener is a mobile app that automatically provides a report after completing a questionnaire. Therefore, sleep questionnaires can be used by people (e.g., with sleep apnea) as a sleep control that can alert them about the need for a proper diagnosis provided by specialists.

Table 2 shows (in chronological order of appearance) the most extended sleep questionnaires used along the last 30 years. For a long time, we have been collecting all of them (some of them are not available online), and we have created a public repository where they all can be downloaded: http://users.dsic.upv.es/ jsilva/Sleep/.

Table 2:
Questionnaires for the detection of sleep disorders.
Each row represents a sleep questionnaire, and includes its acronym, its structure (number of items and scale used), and a reference to the article where it was proposed.
Sleep questionnaire Structure Period Objectivity
MSQ Mini Sleep Questionnaire (Zoomer et al., 1985) 10 items (7 point scale) Recently 0
PSQI Pittsburgh Sleep Quality Index (Buysse et al., 1989) 9 items (4 point scale) 1 month 0
ESS Epworth Sleepiness Scale (Johns, 1991) 8 items (4 point scale) Recently 0
ISI Insomnia Severity Index (Morin, 1993) 7 items (5 point scale) Recently 0
SDQ Sleep Disorders Questionnaire (Douglass et al., 1994) 175 items (5 point scale) Recently 1
SACS Sleep apnea clinical score (Flemons et al., 1994) 4 items (100 point scale) Recently 4
FOSQ Functional Outcomes of Sleep Questionnaire (Weaver et al., 1997) 30 items (4–5 point scale) Recently 0
SAQLI Calgary Sleep Apnea Quality of Life Index (Flemons & Reimer, 1998) 35 items (7 point scale) 1 month 0
OSQ Oviedo Sleep Questionnaire (Bobes et al., 1998) 15 items (4–7 point scale) 1 month 0
BQ Berlin Questionnaire (Netzer et al., 1999) 10 items (2–5 point scale) Recently 2
ASQ Athens Sleep Questionnaire (Soldatos, Dikeos & Paparrigopoulos, 2000) 8 items (4 point scale) 1 month 0
SEMSA Self-efficacy in Sleep Apnea (Weaver et al., 2003) 26 items (4 point scale) Recently/Future 0
SQ STOP Questionnaire (Chung et al., 2008) 4 items (2 point scale) Recently 2
SBQ STOP-BANG Questionnaire (Pallesen et al., 2008) 8 items (2 point scale) Recently 3
BIS Bergen Insomnia Scale (Chasens, Ratcliffe & Weaver, 2009) 6 items (8 point scale) 1 month 0
FOSQ-10 Functional Outcomes of Sleep Questionnaire—10 (Takegami et al., 2009) 10 items (4 point scale) Recently 0
SFV Simple Four Variables (Chai-Coetzer et al., 2011) 4 items (2–6 point scale) Recently 3
OSA50 Obesity, Snoring, Apneas, aged over 50 (Chai-Coetzer et al., 2011) 4 items (3–4 point scale) Recently 4
DOI: 10.7717/peerj.4849/table-2

For each questionnaire, the table shows:

  • Its structure: number of questions/items and the scale used for the answers.

  • The period of time that the questionnaire evaluates: if it is unspecific or unspecified it uses “Recently”, if one or more questions refer to future or hypothetical situations it uses “Future” (e.g., “If I use CPAP I will feel better”, “I would use CPAP, even if I had to pay for some of the cost”, etc.).

  • The percentage of objective questions in the questionnaire: a question that is (partially) subjective or that depends on memory is considered subjective. Only questions that are totally objective are considered objective (e.g., “have you taken drugs to sleep?”, “how much do you weight?”, etc.). The level of objectivity is indicated with a 1–4 scale, where 0 means close to 0%, 1 means close to 25%, 2 means close to 50%, 3 means close to 75%, and 5 means close to 100%.

It is important to note that, although the goal of some questionnaires (e.g., PSQI) is to evaluate sleep quality (such as PSG, and actigraphy), others assess concepts distinct from sleep quality. For example, FOSQ measures the concept of sleepiness, which may or may not be related to sleep quality. Treating objective and subjective measures related to some aspect of sleep as evaluating sleep quality would ignore the fundamental concept on which they were developed and the principle that you select a measure based on the concept you are measuring for alignment and accuracy. Therefore, some questionnaires are fundamentally incomparable, and the selection of one questionnaire should be based on the purpose of each specific questionnaire. Table 3 summarizes the objective of each questionnaire.

Table 3:
Purposes of sleep questionnaires.
Each row represents a sleep questionnaire, and it indicates what does this questionnaire intend to measure.
Sleep questionnaire Acronym Measures
Mini Sleep Questionnaire MSQ Insomnia and hypersomnia
Pittsburgh Sleep Quality Index PSQI Sleep quality and patterns of sleep in adults
Epworth Sleepiness Scale ESS Level of daytime sleepiness. Average sleep propensity in daily life
Insomnia Severity Index ISI Nature, severity, and impact of insomnia. Treatment response in adults
Sleep Disorders Questionnaire SDQ Sleep disturbance and usual sleep habits during the past month only
Sleep apnea clinical score SACS Sleep apnea
Functional Outcomes of Sleep Questionnaire FOSQ Impact of excessive sleepiness on daily life
Calgary Sleep Apnea Quality of Life Index SAQLI Quality of life associated with sleep apnea
Oviedo Sleep Questionnaire OSQ Insomnia and hypersomnia in the last month
Berlin Questionnaire BQ Sleep apnea
Athens Sleep Questionnaire ASQ Sleep quality
Self-Efficacy Measure for Sleep Apnea SEMSA Sleep apnea
STOP Questionnaire SQ Sleep apnea
STOP-BANG Questionnaire SBQ Sleep apnea
Bergen Insomnia Scale BIS Sleep quality
Functional Outcomes of Sleep Questionnaire—10 FOSQ-10 Impact of excessive sleepiness on daily life
Simple Four Variables SFV Sleep apnea
Obesity, Snoring, Apneas, aged over 50 OSA50 Sleep apnea
DOI: 10.7717/peerj.4849/table-3

Having such an availability of different questionnaires (as shown in Table 2, their number of questions and scales vary a lot), the natural question is: “Which sleep questionnaire should I use?” Of course, those questionnaires with less questions are easier to administer, but those questionnaires with more questions collect more information. However, the question remains for those questionnaires with the same number of questions (e.g., SACS, SQ, SFV, OSA50). This question has motivated several studies to compare their sensitivity (true positive rate) and specificity (true negative rate). Some important studies comparing sleep questionnaires for the identification of sleep apnea are summarized in Table 4. The interested reader is referred to Ibáñez, Silva & Cauli (2018) for a survey on sleep questionnaires.

Table 4:
Studies that compare sleep assessment questionnaires.
Each row represents a study that compares 3–5 sleep questionnaires. For each study, the table shows the size of the sample used (amount of people that participated in the study) and which questionnaire produced the best sensitivity and specificity. The reference to each study is also included.
Questionnaires evaluated Sample Best sensitivity Best specificity Reference
ESS vs. SQ vs. SBQ vs. SFV 4,770 SBQ (87.0%) SFV (93.2%) Silva et al. (2011)
ESS vs. BQ vs. SQ vs. SBQ 234 SBQ (97.55%) ESS (75.0%) El-Sayed (2012)
BQ vs. SQ vs. SBQ vs. OSA50 90 SBQ (87%) SBQ (76.0%) Firat et al. (2012)
ESS vs. BQ vs. SQ vs. SBQ 212 SBQ (94.9%) SFV (50.0%) Luo et al. (2014)
ESS vs. BQ vs. SQ vs. SBQ vs. SFV 1,853 SBQ (97.6%) SFV (74.4%) Pataka et al. (2014)
SQ vs. SBQ vs. OSA50 543 OSA50+oximetry (73.0%) OSA50+oximetry (96.0%) Chai-Coetzer et al. (2015)
DOI: 10.7717/peerj.4849/table-4

Sleep diaries

Sleep diaries allow patients to self-assess their sleep. Sleep diaries have one important advantage over sleep questionnaires. While sleep questionnaires are filled in once, sleep diaries are filled in over a period of time (usually one or two weeks). This means that sleep diaries contain more information, and also that the information contained is more precise. This happens because a sleep questionnaire provides an overall perception, often ignoring the details, and it is highly dependent on the patient’s memory because they summarize information about the previous one or two weeks. Contrarily, the sleep diary collects data every day, so that good and bad days are recorded. Moreover, the sleep diary is not so dependent on memory, because they are often filled in just after waking up. We have been collecting sleep diaries from hospitals, sleep centres and different studies. In our repository, there are more than 25 sleep diaries. The most representative are shown in Table 5. We have made them publicly available at: http://users.dsic.upv.es/ jsilva/Sleep/.

The Pittsburgh Sleep Diary (Monk et al., 1994) is the oldest sleep diary in our records (although there is evidence that sleep diaries were in clinical use for decades before its 1994 publication (Weitzman et al., 1982)). After it was proposed, many other diaries have been defined by researchers, hospitals, and sleep centres. In March 2005, 25 researchers attending the Pittsburgh Assessment Conference developed an initiative to compare a collection of sleep diaries in order to extract the best from each diary studied and integrate all together, producing an improved sleep diary. As a result, they proposed the “Consensus Sleep Diary” (Carney et al., 2012) (see Table 5). The diaries included in Table 5 are classified according to the information required from the user. In particular, they include different questions about their sleep such as time used to fall asleep, the amount and kind of food in the dinner, or use of drugs, etc. Specific information about the structure and information gathered by sleep diaries can be found at Ibáñez, Silva & Cauli (2018).

Table 5:
Sleep diaries for the detection of sleep problems.
Each row represents a sleep diary, and it indicates the number of questions included in the diary and the scale used to complete the answers.
Sleep diary Number of questions Scale
Pittsburgh Sleep Diary (PSD) 23 6 point scale
Consensus Sleep Diary (CSD) 20 5 point scale
National Sleep Foundation (NSF) 15 3 point scale
Get Self Help Sleep Diary (GSH) 14 11 point scale
National Heart, Lung, and Blood Institute (NHLBI) 12 3–4 point scale
NPS MedicineWise Sleep Diary (NPS) 11 3 point scale
Loughborough Sleep Research Center (LSRC) 8 5 point scale
DOI: 10.7717/peerj.4849/table-5

There is also the existence of sleep diaries that are distributed as mobile apps. The most used and better valued sleep diaries according to Google Play are Sleep Diary Pro (423 reviews with a mark of 4.2/5), Healthy Sleep Diary (223 reviews with a mark of 3.9/5), and Sleep Diary Lite (2,263 reviews with a mark of 3.8/5). Tonetti, Mingozzi & Natale (2016) compared the use of paper and electronic sleep diaries and concluded that they are similar with respect to their diagnostic power.

Hardware devices

Contactless hardware devices to detect the sleep

Contactless methods to assess sleep use one or more of the following technologies: Microphone (in Nakano et al. (2014) there is an informative discussion about how to quantify snoring and sleep apnea severity), video camera, (infrared) thermometer, pressure strap or belt, pillow or mattress accelerometer, echo-based devices (Lee, Hong & Ryu, 2015) such as sonar, radar, or also lidar (still under development).

There exist periodic expert’s reviews (see, e.g., Langley, 2017; Green, 2017; ASA, 2017) that rank the most valued contactless devices according to the market (e.g., Amazon reviews). However, currently the most used device to assess the sleep is the smartphone. Because a smartphone contains a microphone, a camera, and an accelerometer, it can use these hardware features to monitor sleep. This has promoted the appearance of many mobile apps to assess sleep. The main contactless sleep detection apps according to the number of reviews in Google Play are shown in Table 6. Even though several experts’ reviews (see, e.g., Hacktosleep, 2016; Maslakovic, 2017) report high performance and reliability of these apps, there are still few scientific validation studies that support this claim. In contrast, several studies report that mobile apps are not yet prepared for clinical use (Kolla, Mansukhani & Mansukhani, 2016; Ong & Gillespie, 2016; Patel, Kim & Brooks, 2017; Lorenz & Williams, 2017). For instance, a recent study (Patel, Kim & Brooks, 2017) performed with 25 children (ages: 2–14) and where a smartphone recorded data simultaneously with a PSG suggested that smartphone apps may have value in increasing the user’s awareness of sleep issues but would not yet be accurate enough to be used as a clinical tool.

Table 6:
Contactless sleep detection apps (prices and reviews are taken from Google Play).
Each row shows a sleep app. Rows are sorted in descending order according to the average review mark.
App name Developer Price Average review Number of reviews
Sleep as Android Unlock Urbandroid Team 3.99$ 4.5 out of 5 23,686
Sleep Cycle Alarm Clock Northcube AB 0$ 4.4 out of 5 47,965
Sleep as Android Urbandroid Team 0$ 4.3 out of 5 244,840
Sleep Better Runtastic 0$ 4.1 out of 5 108,825
Sleep Time Azumio Inc. 0$ 4.1 out of 5 30,418
Smart Sleep Manager 株式会社 C2 0$ 4.1 out of 5 18,805
Good Night’s Sleep Alarm Ateam Inc. 0$ 4.1 out of 5 10,022
SleepBot SleepBot 0$ 4.0 out of 5 51,111
Smart Alarm Clock Nelurra Holdings LTD 0$ 3.9 out of 5 27,442
Sleep Analyzer A1 Brains Infotech 0$ 3.1 out of 5 2,461
DOI: 10.7717/peerj.4849/table-6

Contact hardware devices to detect the sleep

Contact hardware devices to assess sleep are small devices that can be attached to the wrist, chest, ankle, or head. Some of these devices use the Cartesian representation to record the activity of the body and thus they are known as actigraphs. Most actigraphs use an accelerometer to register movements. The information collected is used to analyse sleep. Even though contemporary actigraph devices are electronic, the first actigraphs were mechanical (contrary to common belief). In fact, the first actigraphs date from the 1950s (Tryon, Bellak & Hersen, 1991).

Due to the usefulness of the information collected by actigraphs, the use of actigraphy has been included in the ICSD-3 diagnostic criteria for several circadian sleep-wake rhythm disorders. Even though there is a clear continual improvement in the precision of sensors, and in the accuracy of algorithms, the use of actigraphs for clinical diagnosis should be considered when the device and algorithm used have been validated. In particular, the algorithm used to interpret the data is of major importance, because many proprietary algorithms do not pass enough quality controls, and some of them are even worse than the human inspection of the actigraphy data (see, e.g., Boyne et al., 2013).

The performance and reliability of hardware devices have been compared by experts’ reviews (see, e.g., Maslakovic, 2017) and also by validation studies (Evenson, Goto & Furberg, 2015; Kolla, Mansukhani & Mansukhani, 2016). However, it is important to note that fitness trackers and phone apps tend to underestimate sleep disruptions and overestimate total sleep times and sleep efficiency in normal subjects (Kolla, Mansukhani & Mansukhani, 2016).

A Critical Discussion About Accuracy and Validation

Each sleep detection method has its own level of reliability and precision. If we place the presented methods in order of accuracy, as reported in the literature (Boyne et al., 2013; Evenson, Goto & Furberg, 2015; Ibáñez, Silva & Cauli, 2018), we have:

Questionnaire < Sleep diary < Contactless devices < Contact devices < PSG

It is important to note that this formulation does not pretend to sort the methods according to their usefulness. It would be erroneous to state that self-reporting is inferior (or less useful) to more objective measures. This would fail to appreciate that data based on patient perception may be valuable in understanding sleep problems.

Being both mostly subjective, there is an important difference in the way that sleep diaries and questionnaires are completed. Questionnaires are filled in once, usually before the interview with the sleep therapist, thus, not just after waking up. Consequently, (1) the patient’s memory strongly influences the quality of the information provided (he or she has to remember his or her sleep for a week or a month); and (ii) the information provided is a summary of many sleeps, thus, losing details about special days. In contrast, sleep diaries (1) are filled in every day, and (2) they are completed just after waking up. Hence, they are potentially more accurate and less influenced by the memory of the patient. Therefore, the amount of information and accuracy of sleep diaries is objectively superior to that of questionnaires. Here again, the superiority in precision of sleep diaries does not substitute the global assessment of sleep questionnaires, and the latter may be the relevant data therefore making the questionnaire more pertinent.

The accuracy of sleep questionnaires has been widely studied (see, e.g., Silva et al., 2011; Firat et al., 2012; El-Sayed, 2012; Pataka et al., 2014; Luo et al., 2014; Chai-Coetzer et al., 2015; Silva et al., 2016, and see Table 4 where studies that evaluated sleep questionnaires are compared). All these studies used the PSG as a gold standard and tried to evaluate the sensitivity/specificity of the questionnaires in identifying sleep apnea. The sensitivity reported was in the interval 73.0%–97.6%, while the specificity reported was in the interval 50%–96% (see Table 4). Most of the studies reported the STOP-BANG questionnaire as the one producing the best sensitivity. These studies are definitely useful, and provide good indicators, but our selection of a specific questionnaire must consider the specific illness and population targeted. Precisely because they target different populations the results of these studies are not always directly comparable. For instance, the study in Silva et al. (2011) was performed on highway bus drivers in Turkey and the study in Chai-Coetzer et al. (2015) only considered men, etc.

The effectiveness of sleep diaries has been evaluated in Jungquist et al. (2015) and Tonetti, Mingozzi & Natale (2016). These studies also compare paper diaries and electronic diaries using an actigraph as the gold standard. Both studies found that, statistically, paper and electronic diaries collect the same data; thus, their accuracy and reliability is similar.

The main difference between contact and contactless devices is their underlying technology. In general, contact devices are more accurate because most of the sensors used to monitor sleep are strongly dependent on their distance from the patient (the closer the better). A good example are the accelerometers, which are sensors used in both contact devices such as wrist watches, and contactless devices such as mattress or pillow clips. It is fairly evident that it is much more reliable to directly measure the movements of the body than approximating them by measuring the movements of the mattress or pillow. The same happens with sonars, for example. A phone’s microphone and speaker using ultrasounds as a sonar have an effective range of about 1 metre and its reliable distance is 0.5 m. Of course, the results are more precise as the patient is closer. Unfortunately, the movements of the sonar can negatively affect its measurements and results, hence it is preferable putting it on a bedside table, lying still, instead of putting it on the mattress. As a consequence, the sonar is often at least 0.5 m away from the patient. This problem also happens with similar radio frequency technology used to monitor the body movements and breathing.

One of the main factors that influence the accuracy of sleep detection devices is the quality of their sensors. An informative discussion and comparison of sensors’ accuracy appears in Lee & Finkelstein (2015). Another important factor is the software that process the data collected by the sensor. Currently, there are more than 100,000 health apps in the Apple and Google Play app stores (Research 2 Guidance, 2016). Many of these apps focus on sleep, and a large proportion of them implement proprietary sleep detection algorithms. As a consequence, the same device (e.g., a mobile phone with an accelerometer) can produce different results depending on the underlying software that process the data collected.

It is therefore very important to highlight that most of the publicly available sleep apps have not been clinically validated. Most of them are implemented and maintained by independent (non-clinical) programmers and, thus, their clinical use is not recommended. Of course, there have been many studies devoted to validating hardware devices and reporting on their accuracy and precision. Some studies devoted to validating actigraphs are Sivertsen et al. (2006), Paquet, Kawinska & Carrier (2007), Sitnick, Goodlin-Jones & Anders (2008), Montgomery-Downs, Insana & Bond (2012), Marino et al. (2013), Meltzer et al. (2014), De Zambotti, Baker & Colrain (2015), Bhat et al. (2015), Toon et al. (2016) and Meltzer et al. (2016). They all study the correlation between one commercial actigraph and a PSG (the patient wore the actigraph during the PSG). The sensitivity reported is in the interval 86%–98%, and the specificity is in the interval 20%–54%, because commercial actigraphs prioritize sensitivity over specificity. The interested reader is referred to Evenson, Goto & Furberg (2015) and Kolla, Mansukhani & Mansukhani (2016) where systematic reviews of validation studies for sleep detection hardware devices can be found. Other works study the precision of actigraphy with specific populations (children, adults, old women, mentally disordered, etc.) (Blackwell et al., 2008; Martin & Hakim, 2011; Marino et al., 2013; Baandrup & Jennum, 2015; Min et al., 2014; De Zambotti et al., 2015; Meltzer et al., 2016).

The review of the state of the technology together with the review of the validation studies advise against using contactless devices in the clinical study of sleep. Their low precision renders them far from being a reliable method. This does not mean that they are useless. They are good sleep indicators, and a good resource for patients to monitor and be aware of their own sleep quality. But their use as a definitive diagnostic tool is to be discouraged. In the case of contact devices, their precision is acceptable for many populations. In general, they should be used as an indicator but not as a definitive diagnostic tool, because several studies report that their sensitivity can fall down to 86% and their specificity to 20%. However, these numbers are on the increase because the advances in technology are continuously improving such devices. This is also observable in the continuous increment of precision reported over time by validation studies.

The first conclusion of this review is that a perfect sleep assessment method does not exist. All methods have advantages and disadvantages, thus, they should be combined and adapted to the specific applicable needs. In terms of accuracy, the PSG is the best method, reporting the most complete and precise information (e.g., differentiating the sleep phases). Nevertheless, PSGs are expensive, exclusive (they require special hardware and medical support), can only be administered once, or for a few days, and they assess sleep in a stressful context (e.g., a hospital with video cameras recording and several machines registering the information provided by electrodes placed in the patient’s body).

For these reasons, sleep diaries and questionnaires are often used to complement the PSG. They provide information that is gathered over medium to long periods of time, including information about sleep habits. Because they are mostly subjective, they have been erroneously considered as unreliable. But, in contrast, several studies (see Table 4) have proven that their sensitivity is often above 90%, and between 73% and 97.7% in all the discussed studies. Specificity ranges in the interval 50%–96%. In the specific case of electronic diaries, the studies demonstrate that they produce the same results as their paper counterparts, but also that they provide functional advantages: automatic data processing, metadata such as information about when the patient filled in the diary, alerts, etc. Sleep questionnaires and diaries have been classified in Tables 2 and 5, respectively.

The literature review shows that the accuracy of hardware devices is superior to that of questionnaires. This superiority, however, must be considered only in terms of precision, but not in terms of diagnostic usefulness. The information provided by questionnaires regarding self-perception of sleep quality is essential and cannot be replaced by hardware measures. The sensitivity of hardware devices is 88–98%, while their specificity is 20–52%. The adherence of hardware devices is also superior, because they require less effort from the patient (e.g., actigraphs are mostly automatic). The accuracy and reliability of hardware devices have been continuously increased with the advances of the technology. The continuous improvement of sensors and the appearance of new technologies (good examples are the imminent use of infrared thermometers and lidars) clearly improve the sleep detection devices.

We have presented a taxonomy of sleep methods that comprises all methods presented. This taxonomy classifies hardware devices into contact and contactless devices, because their functionality, accuracy, and reliability are different. In both cases, many studies reach the similar conclusion that current sleep trackers are useful tools to assess sleep and have been used successfully in many sleep studies. In particular, the studies that have evaluated concrete actigraphs with their respective software/app conclude that actigraphy is a reasonably reliable method to detect sleep with an average sensibility higher than 90%. Nevertheless, the studies also report that the results obtained are particularly influenced by the patient that wears the actigraphy, which can produce bad results in many cases. Therefore, the use of actigraphy as a diagnostic tool should be complemented and contrasted with other methods to produce a more definitive diagnostic.

Finally, sleep apps are another important tool to assess sleep, especially in smartphones, where they are becoming very common nowadays. We have shown the most significant apps with regard to their number of reviews, and to their overall mark given by users. It is important to highlight that, contrasted with hardware, software apps are often implemented by independent (non-clinical) developers, and they do not pass any quality test. Therefore, they must be validated, at least before they are applied in clinically. The few scientific validation studies that have compared smartphone apps against PSG report that they are still not accurate enough to be used as clinical tools.


In Search of the Perfect Board

by Preconceived Noceans

It is no doubt that catching and riding waves in the Great Lakes is challenging. We have been considering and researching different boards to find which shapes would be the best for the lake. The waves are generated mostly by wind, and lack the power that ground swell in the ocean can bear. The lakes also is deficient in its salt concentration, which adds much more buoyancy in the ocean. So the bigger thicker boards are generally used and more dominating in the lake, but sometimes with a hit to performance.

One shape that will always work for the lake waves is a longboard. Luke and Amelia started shaping this 9’5″ in their studio a few weeks ago. They glassed the hull today, which was really cool to see for the first time. They plan to shape more boards and experiment to find the perfect board for the lakes.


Why does the Sun usually appear white to the human eye? How do stars that are cooler, hotter, and about the same temperature compare to the Sun?

What will be the ideal response?

ANSWER: Because the Sun radiates almost half of its energy as visible light, all visible wavelengths from the midday Sun reach the cones, and the Sun usually appears nearly white. A star that is cooler than our Sun radiates most of its energy at slightly longer wavelengths; therefore, it appears redder. On the other hand, a star much hotter than our Sun radiates more energy at shorter wavelengths and thus appears bluer. A star whose temperature is about the same as the Sun’s appears white.

Very useful! Thanks for sharing.


God, the Foundation for Everything

God is a foundational assumption that must be in place to have an intelligible view of the universe. It’s not that unbelievers don’t think intelligently about the universe, but their most basic assumptions about it are hostile to the way they engage the world around them. Without God, morality becomes impossible to justify. As do scientific laws, and laws of logic. These have to be designed by Someone and deliberately set within our universe, or we have every reason to doubt their existence, or at least wonder if they actually mean what we have always assumed them to mean. Honest unbelief requires contemplating the possibility that  we might just be lying to ourselves about what the universe is, and what we are.

Revelation is Bound Up with the Idea of a Transcendent God


December 2017 - Double Star of the Month

The two pairs selected for December are both wide, unequal double stars.

WEB 2 (03 42 42.73 +59 58 09.8) appears in the first edition of Celestial Objects for Common Telescopes. In it, Webb calls the primary star P III 97 and in examining Piazzi's Palermo Catalogue you will find that Piazzi did indeed record the primary star and also the secondary. He adds a note saying another telescopic (star) follows to the north, so this is, in fact, a discovery by Piazzi.

Webb was almost certainly drawn towards this star because of his abiding interest in red stars. His notes say orange with scarlet blaze and bl(ue). for the colours of the components which is a good enough reason to observe this pair.

The magnitudes are 5.7 and 8.9 and the current position of B is 33° and 54 arcseconds but there is no evidence that the stars are are in any other way connected. Espin added two fainter, closer stars in PA 33° and 98° and there is an 11.8 magnitude at 168 arcseconds along PA 162°.

WEB 2 is close to STF 385, STF 389, STF 396 and STF 400, 15 degrees due north of Mirfak (alpha Per).

H 3 80 (02 26 00.38 -15 20 28.0) is in Cetus in a fairly sparse area of sky about 12° south of Mira, 1.5 degrees preceding σ Ceti towards τ Ceti.

Herschel came across this pair on October 13th, 1782. He measured the distance as 11.2 arcseconds and the PA at 292°. There has been little change in either coordinate since then.

The stars are magnitudes 5.9 and 9.1 and the primary is a A star although William Herschel called it reddish white, whilst the companion appeared bluish-red to him.

The primary star (AB Ceti) is both a spectroscopic binary and a member of the Alpha2 CVn class of variables. These are main-sequence stars which display strong magnetic fields and whose spectra show abnormally strong lines of Si, Sr, Cr, and rare earths. They exhibit magnetic field and brightness changes and the amplitudes of the brightness changes are usually no greater than 0.1 magnitude in V.

Bob Argyle - Double Star Section Director


Social media addiction may be hereditary: study

Washington, May 4 (PTI) Hooked to Facebook or Twitter? Your genes may be to blame, as scientists have found that social media addiction is influenced more by heredity, rather than environmental factors.

Researchers from Kent State University in the UK used a behaviour genetics framework and twin study data from a 2013 survey.

The data analysed revealed one- to two-thirds of variance in social media use is attributable to additive genetic traits, unique and shared environmental factors account for the remainder of variance.

Past behaviour genetics research shows genetic influence on a wide range of communication behaviours, researchers said.

"This study does not suggest that using DF regression with twin survey data, or the behavioural genetics perspective more generally, can directly assess gene-level influence on specific behaviours. There is no social media gene," said Chance York from Kent State University.

"The assumption here is that known genetic variation between fraternal and identical twins can be leveraged to study how genetic variation influences patterns of observable behaviour," he said.

"We are still working in a black box in that we can not directly observe how genes impact our neuroanatomy, which in turn impacts cognitive processing, personality, and subsequent media selection and effects," York said. PTI APA MHN SAR MHN

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Viola part from BERLIOZ, H. - The Shepherds Farewell. arr. for String Quartet by Gerald Manning

H. Berlioz
3 minutes
Classical music
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Berlioz�s leanings towards music were an anomaly in his family. His father, a doctor and prominent citizen of La Cote-St-Andre, Isere where Hector was born on 11 December 1803, intended his son to follow his own profession, so at the age of 17 he went to Paris to pursue a medical career. He became a habitu� of the Opera, and in the face of an increasing weakening of his slight interest in medicine and parental displeasure he soon abandoned his medical studies in favour of a career in music. His modest income as a professional musician was eked out at first by singing in a theatre chorus and by giving guitar lessons. Berlioz wrote no solo music for the piano and no chamber music exists; he composed mainly for voices and instruments in many combinations and genres. The shepherds bid farewell to the Holy Family (to give it it�s full title) comes from the second part of his Sacred Trilogy L�Enfance du Christ; it was originally scored for two oboes, two clarinets, chorus and strings � here it is in an arrangement for string quartet.

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The role of radiosurgery for hemangiopericytomas.

OBJECT Hemangiopericytomas represent a small subset of meningeal tumors. Despite their relatively uncommon nature, they are aggressive tumors known for recurrence. Resection is the standard treatment in most, although regrowth and metastases are common even after resection. The authors evaluate the role of stereotactic radiosurgery in the treatment of… (More)

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Getting The Most Out Of Your Dance Class

As children, parents and carers spend lots of time and money committing to dance lessons, even when they take joy from watching rather than doing. Taking children to dancing lessons requires energy and time, not to mention additional funds for competitions, costumes and extra performances. For a child, it is not until later that they see dance lessons in the same way, as an investment. Only then do they see that time, money and energy go to waste when they do not make the most of their dance lessons.

It is understandable that every dancer experiences a rut in their training, where they may not want to attend classes or feel they are not improving at the rate they should be. Despite this, it is not the dancers that stretch the most, sweat more or practice at home at all hours that necessarily get the most out of their dance classes either. The correct mental attitude is hugely important in dance training, to understand the purpose of dance for yourself and how to experience it in the best possible way.

When dancers become older, their adult freedom equates to a similar responsibility for themselves, be it getting themselves to classes, paying for their own training or beginning to assist with the teaching at the local dance studio. With these aspects comes heightened responsibility, for learning, fuelling and directing your dancing. It goes without saying that dancers must therefore arrive early and prepared for class, being focused and dedicated to the class, taking and applying corrections that are given to the class and spending time on the parts that need the most improvement, even if that means going back to basics.

Making mistakes is a large part of dance training; it will mean you will discover something new about the dancing body, through listening, watching, or error, even if this feels uncomfortable. Don’t forget to enjoy the process and thank your teachers for giving you the tools to better yourself and work hard in each class you take.