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The Microsoft Store, which serves as a unified storefront for apps and other content, is also redesigned in Windows 11. Microsoft now allows developers to distribute Win32, progressive web applications, and other packaging technologies in the Microsoft Store, alongside Universal Windows Platform apps. Microsoft also announced plans to allow third-party application stores (such as Epic Games Store) to distribute their clients on Microsoft Store. Windows 11 supports x86-64 software emulation on ARM-based platforms.
The collaboration platform Microsoft Teams is integrated into the Windows 11 user interface, and is accessible via the taskbar. Skype will no longer be bundled with the OS by default. In early 2023, the Phone Link app gained limited support for iMessage.
Microsoft claims performance improvements such as smaller update sizes, faster web browsing in "any browser", faster wake time from sleep mode, and faster Windows Hello authentication.
Windows 11 ships with the Chromium-based Microsoft Edge web browser (for compatibility with Google Chrome web browser), and does not include or support Internet Explorer. Its rendering engine MSHTML (Trident) is still included with the operating system for backwards compatibility reasons, and Edge can be configured with Group Policy to render whitelisted websites in "IE Mode" (which still uses IE's rendering engine MSHTML, instead of Blink layout engine). Windows 11 is the first version of Windows since the original retail release of Windows 95 to not ship with Internet Explorer.
The updated Xbox app, along with the Auto HDR and DirectStorage technologies introduced by the Xbox Series X and Series S, will be integrated into Windows 11; the latter requiring a graphics card supporting DirectX 12 and an NVMe solid-state drive.
User interface
A redesigned user interface is present frequently throughout the operating system, building upon the Fluent Design System; translucency, shadows, a new color palette, and a rounded geometry are prevalent throughout the UI. A prevalent aspect of the design is an appearance known as "Mica", described as an "opaque, dynamic material that incorporates theme and desktop wallpaper to paint the background of long-lived windows such as apps and settings". Much of the interface and start menu takes heavy inspiration from the now-canceled Windows 10X. The Segoe UI font used since Windows Vista has been updated to a variable version, improving its ability to scale between different display resolutions. | Windows 11 | Wikipedia | 485 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
The taskbar's buttons are center-aligned by default, and it is permanently pinned to the bottom edge of the screen; it cannot be moved to the top, left, or right edges of the screen as in previous versions of Windows without manual changes to the registry. The notifications sidebar is now accessed by clicking the date and time, with other Quick Actions toggles, as well as volume, brightness, and media playback controls, moved to a new settings pop-up displayed by clicking on the system tray. The "Widgets" button on the taskbar displays a panel with Microsoft Start, a news aggregator with personalized stories and content (expanding upon the "news and interests" panel introduced in later builds of Windows 10). Microsoft Teams is similarly integrated with the taskbar, with a pop-up showing a list of recent conversations.
The Start menu has been significantly redesigned, replacing the "live tiles" used by Windows 8.x and 10 with a grid of "pinned" applications, and a list of recent applications and documents. File Explorer was updated to replace its ribbon toolbar with a more traditional toolbar, while its context menus have been redesigned to move some tasks (such as copy and paste) to a toolbar along the top of the menu, and hide other operations under an overflow menu.
Task View, a feature introduced in Windows 10, features a refreshed design, and supports giving separate wallpapers to each virtual desktop. The window snapping functionality has been enhanced with two additional features; hovering over a window's maximize button displays pre-determined "Snap Layouts" for tiling multiple windows onto a display, and tiled arrangement of windows can be minimized and restored from the taskbar as a "snap group". When a display is disconnected in a multi-monitor configuration, the windows that were previously on that display will be minimized rather than automatically moved to the main display. If the same display is reconnected, the windows are restored to their prior location.
Windows Subsystem for Android | Windows 11 | Wikipedia | 416 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
On October 21, 2021, Windows Subsystem for Android (WSA) became available to Beta channel builds of Windows 11 for users in the United States, which allows users to install and run Android apps on their devices. Users can install Android apps through any source using the APK file format. An Amazon Appstore client for Microsoft Store is also available. The Windows Subsystem for Android and Amazon Appstore became available to Release channel users in the United States on February 15, 2022, in Windows 11 Release build 22000.527. On March 5, 2024, Microsoft announced deprecation of WSA with support ending on March 5, 2025.
WSA is based on the Intel Bridge runtime compiler; Intel stated that the technology is not dependent on its CPUs, and will also be supported on x86-64 and ARM CPUs from other vendors.
Setup
Home and Pro (since version 22H2) edition installation requires internet connection and Microsoft account login (only if for personal use on Pro) is mandatory unless manually bypassed to create a local user. However, Microsoft has since blocked one of the last remaining easy bypass methods that allowed local account creation during initial setup, complicating the bypass process further. All other editions are excluded from this requirement.
System security
As part of the minimum system requirements, Windows 11 only runs on devices with a Trusted Platform Module 2.0 security coprocessor, albeit with some exceptions, see for details. According to Microsoft, the TPM 2.0 coprocessor is a "critical building block" for protection against firmware and hardware attacks. In addition, Microsoft now requires devices with Windows 11 to include virtualization-based security (VBS), hypervisor-protected code integrity (HVCI), and Secure Boot built-in and enabled by default. The operating system also features hardware-enforced stack protection for supported Intel and AMD processors for protection against zero-day exploits.
Like its predecessor, Windows 11 also supports multi-factor authentication and biometric authentication through Windows Hello. | Windows 11 | Wikipedia | 423 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
Artificial intelligence
In subsequent updates, Microsoft added several features based on artificial intelligence (AI), like live captions, background noise removal in videoconferencing, webcam auto-framing that follows the user's movements, and AI-powered Bing Chat in the taskbar's search field. Following the integration of GPT-4 in Microsoft's other products, the company announced that by summer 2023, the newly released Microsoft Copilot would add GPT-4 integration to the Windows taskbar.
On May 20, 2024, Microsoft officially announced Recall, a feature that uses a hardware AI accelerator to locally store snapshots of the user's activity (including content transcribed using live captions), and which allows users to search through them. This feature is exclusive to devices certified under the "Copilot+ PC" branding. Following pushback from the cyber security community, Microsoft delayed the feature in June 2024. A preview version will be added to the Microsoft Insider program at later date in order to test added security measures.
Editions
Windows 11 is available in two main editions; the Home edition, which is intended for consumer users, and the Pro edition, which contains additional networking and security features (such as BitLocker), as well as the ability to join a domain. Windows 11 Home may be restricted by default to verified software obtained from Microsoft Store ("S Mode"). Windows 11 Home requires an Internet connection and a Microsoft account in order to complete first-time setup. This restriction is also applied to Windows 11 Pro since version 22H2 as it was announced in February 2022, although a Microsoft account isn't required if it's not for personal use. | Windows 11 | Wikipedia | 347 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
Windows 11 SE was announced on November 9, 2021, as an edition exclusively for low-end devices sold in the education market; it is intended as a successor to Windows 10 S, and also competes primarily with ChromeOS. It is designed to be managed via Microsoft Intune. Based on feedback from educators, Windows 11 SE has multiple UI differences and limitations, including Snap Layouts not containing layouts for more than two applications at once, all applications opening maximized by default, and Widgets being removed. It is bundled with applications such as Microsoft Office for Microsoft 365, Minecraft Education Edition, and Flipgrid, while OneDrive is used to save files by default. Windows 11 SE does not include Microsoft Store; third-party software is provisioned or installed by administrators. To target organizations migrating from Google Chrome, Microsoft Edge is configured by default to enable the installation of extensions from the Chrome Web Store.
Other editions
Other editions include Pro Education, Pro for Workstations, Education, Enterprise, Enterprise multi-session, IoT Enterprise, Enterprise LTSC, IoT Enterprise LTSC, Home Single Language, and Team; along with regional variations. These editions remain fundamentally the same as their Windows 10 edition counterparts.
Two new editions called IoT Enterprise Subscription and IoT Enterprise Subscription LTSC have been introduced in version 24H2.
Supported languages
Before the launch of Windows 11, OEMs (as well as mobile operators) and businesses were offered two options for device imaging: Component-Based Servicing lp.cab files (for the languages to be preloaded on the first boot) and Local Experience Pack .appx files (for the languages available for download on supported PCs). The 38 fully-localized Language Pack (LP) languages were available as both lp.cab and .appx packages, while the remaining 72 partially-localized Language Interface Pack (LIP) languages were only available as .appx packages.
With Windows 11, that process has changed. Five new LP languages were added — Catalan, Basque, Galician, Indonesian, and Vietnamese — bringing the total number of LP languages to 43. Furthermore, these 43 languages can only be imaged using lp.cab packages. This is to ensure a fully supported language-imaging and cumulative update experience. | Windows 11 | Wikipedia | 454 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
The remaining 67 LIP languages that are LXP-based will move to a self-service model, and can only be added by Windows users themselves via the Microsoft Store and Windows Settings apps, not during the Windows imaging process. Any user, not just admins, can now add both the display language and its features, which can help users in business environments, but these exact options for languages (both LP and LIP) still depend on the OEM and mobile operator.
Updates and support
Like Windows 10, Windows 11 follows Microsoft's Modern Lifecycle Policy. Each annual feature update has its own support lifecycle: two years for the Home and Pro editions, and three years for the Education and Enterprise editions. Microsoft has stated that Windows 11 provides no lifecycle guarantee if it has been installed on a machine that does not meet its minimum hardware requirements.
Windows 11 receives annual major updates, though Microsoft sometimes adds major features in mid-cycle releases. Starting in 2022, in the Enterprise and Education editions, major features added in yearly releases will be turned off by default until the next yearly release, though these features can be manually enabled as a group policy.
Preview releases
The Windows Insider program carries over from Windows 10, with pre-release builds divided into "Dev" (unstable builds used to test features for future feature updates), "Beta" (test builds for the next feature update; relatively stable in comparison to Dev channel), and "Release Preview" (pre-release builds for final testing of upcoming feature updates) channels.
Versions
System requirements
Official
The basic system requirements of Windows 11 differ significantly from Windows 10. Windows 11 only supports 64-bit systems such as those using an x86-64 or ARM64 processor; IA-32 and ARM32 processors are no longer supported. Thus, Windows 11 is the first consumer version of Windows not to support 32-bit processors (although Windows Server 2008 R2 is the first version of Windows Server to not support them). The minimum RAM and storage requirements were also increased; Windows 11 now requires at least 4 GB of RAM and 64 GB of storage. S mode is only supported for the Home edition of Windows 11. | Windows 11 | Wikipedia | 436 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
As of August 2021, the officially supported list of processors includes eighth generation Intel Core CPUs (Coffee Lake) and later, AMD Zen+ CPUs/APUs and later (which include the "AF" revisions of Ryzen 1000 CPUs, which are underclocked Zen+ CPUs that supplant Ryzen 1000 parts that could no longer be manufactured due to a change in process), and Qualcomm Snapdragon 850 and later. The compatibility list includes the Intel Core i7-7820HQ, a seventh-generation processor used by the Surface Studio 2, although only on devices that shipped with DCH-based drivers.
Original equipment manufacturers (OEM) can still ship computers without TPM 2.0 enabled upon Microsoft's approval.
On May 20, 2024, Microsoft announced "Copilot+ PC"—a brand of Windows 11 devices that are designed to support enhanced artificial intelligence features. Copilot+ PCs require an on-board AI accelerator, at least 256 GB of storage, and at least 16 GB of RAM. The first wave of Copilot+ PCs run the Qualcomm Snapdragon X Elite system-on-chip. x86-64-based Copilot+ PCs began to be announced later in the year, which are based on AMD Ryzen AI and Intel Core Ultra CPUs.
Unofficial
Devices with unsupported 64-bit processors are not blocked from installing or running Windows 11; however, a clean install or upgrade using ISO installation media must be performed as Windows Update will not offer an upgrade from Windows 10. Additionally, users must also accept an on-screen disclaimer stating that they will not be entitled to receive updates, and that damage caused by using Windows 11 on an unsupported configuration are not covered by the manufacturer's warranty.
In addition, various unofficial methods to bypass other Windows 11 requirements, such as, but not limited to, TPM 2.0 exist; furthermore there also exists an official bypass method provided directly by Microsoft (whereas the installation itself remains unofficially supported). | Windows 11 | Wikipedia | 430 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
In April 2024, Windows Insider version 24H2 builds began to have a dependency of the SSE4.2 and POPCNT CPU instructions (corresponding to the x86-64 v2 microarchitecture level), increasing the unofficial minimum compatibility to Bulldozer microarchitecture-based processors like the AMD FX (2011) processors and first-generation Intel Core i (2008) processors. Intel Core 2 (like the Core 2 Duo and Core 2 Quad), AMD K10 CPUs (such as Phenom II and Athlon II) and older are no longer supported. Finally, version 24H2 now requires ARMv8.1, dropping unofficial support for ARMv8.0. E.g., the Snapdragon 835 and older are no longer supported.
Firmware compatibility
Legacy BIOS is no longer officially supported; a UEFI system and a Trusted Platform Module (TPM) 2.0 security coprocessor is now officially required. The TPM requirement in particular has led to confusion as many motherboards do not have TPM support, or require a compatible TPM to be physically installed onto the motherboard. Many newer CPUs also include a TPM implemented at the CPU level (with AMD referring to this as "fTPM", and Intel referring to it as "Platform Trust Technology" [PTT]), which might be disabled by default and require changing settings in the computer's UEFI firmware, or a UEFI firmware update that changes the default settings to reflect these requirements.
ARM64 version of Windows 11 requires the UEFI firmware with ACPI protocol.
Starting with version 24H2, IoT Enterprise editions have officially reintroduced legacy BIOS support and eliminated the requirement for a TPM.
Third-party software
Some third-party software may refuse to run on configurations of Windows 11 that do not comply with the hardware security requirement. After the release of Windows 11, Riot Games' kernel-level anti-cheat system Vanguard—used in Valorant and since May 2024 by League of Legends—began to enforce the operating system security requirements, and will not allow the games to be run on the OS if secure boot and a TPM 2.0-compliant coprocessor are not enabled.
IoT Enterprise editions | Windows 11 | Wikipedia | 478 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
While IoT Enterprise editions have always had slightly reduced official requirements compared to other Windows 11 editions, notably starting with version 24H2, minimum requirements were further reduced and now differ significantly. These updated 24H2 requirements were announced on May 22, 2024, for both LTSC and non-LTSC editions.
For the first time since Windows 11 release, Microsoft has officially eliminated a TPM and UEFI minimum requirement for all systems running these editions and dropped the minimum DirectX version down to 10 (version 12 was previously required on 23H2). Finally, the IoT Enterprise LTSC edition further drops the minimum required RAM to 2 GB and storage space to 16 GB.
Reception
Pre-release
Reception of Windows 11 upon its reveal was positive, with critics praising the new design and productivity features. However, Microsoft was criticized for creating confusion over the minimum system requirements for Windows 11. The increased system requirements (compared to those of Windows 10) initially published by Microsoft meant that up to 60 percent of existing Windows 10 PCs were unable to upgrade to Windows 11, which has faced concerns that this will contribute to electronic waste.
Microsoft has not specifically acknowledged this when discussing the cutoff, it was also acknowledged that the sixth and seventh generation of Intel Core processors were prominently afflicted by CPU-level security vulnerabilities such as Meltdown and Spectre, and that newer CPUs manufactured since then had increased mitigations against the flaws.
Speaking to IT news outlet CRN, a dozen solution providers all felt that they "believe Windows 11 will be a meaningful step up in security, and they agree with Microsoft's strategy of putting security first."
Research Vice President of Gartner Stephen Kleynhans felt that Microsoft was "looking at the entire stack from the hardware up through the applications and the user experience and trying to make the entire stack work better and more securely. | Windows 11 | Wikipedia | 380 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
Launch
Andrew Cunningham of Ars Technica gave a mixed but overall cautiously positive review of Windows 11 upon its release. He praised the improvements to its visual design (describing the new "Mica" appearance as reminiscent of the visual appearance of iOS and macOS, and arguing that Microsoft had "[made] a serious effort" at making the user-facing aspects of Windows 11 more consistent visually. He also praised window management, performance (assessed as being equivalent to if not better than Windows 10), other "beneficial tweaks". Criticism was raised towards Widgets' lack of support for third-party content, thus limiting it to Microsoft services only, regressions in taskbar functionality and customization. He also noted the inability to easily select default applications for common tasks such as web browsing, as it requires the user to select the browser application for each file type individually. Apart from the user interface, system requirements and Microsoft's unclear justification for its processor compatibility criteria remained a major sticking point for him. While some of the system requirements have brought greater public attention to hardware security features present on modern PCs, he argued that these could already be employed on Windows 10, albeit optionally. Cunningham concluded that "as I've dug into [Windows 11] and learned its ins and outs for this review, I've warmed to it more", but argued that the OS was facing similar "public perception" issues to Windows Vista and Windows 8. However, he noted that 11 did not have as many performance issues or bugs as Vista had upon its release, nor was as "disjointed" as 8, and recommended that users who were unsure about the upgrade should stay on Windows 10 in anticipation of future updates to 11. | Windows 11 | Wikipedia | 350 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
Tom Warren of The Verge described Windows 11 as being akin to a house in the middle of renovations, but that "actually using Windows 11 for the past few months hasn't felt as controversial as I had expected"—praising its updated user interface as being more modern and reminiscent of iOS and ChromeOS, the new start menu for feeling less cluttered than the Windows 10 iteration, updates to some of its stock applications, and Snap Assist. Warren noted that he rarely used the Widgets panel or Microsoft Teams, citing that he preferred the weather display that later versions of Windows 10 offered, and did not use Teams to communicate with his friends and family. He also acknowledged the expansion of the Microsoft Store to include more "traditional" desktop applications. However, he felt that Windows 11 still felt like a work in progress, noting UI inconsistencies (such as dark mode and new context menu designs not being uniform across all dialogues and applications, and the UWP Settings app still falling back upon legacy Control Panel applets for certain settings), regressions to the taskbar (including the inability to move it, drag files onto taskbar buttons to focus the corresponding application, and the clock only shown on the primary display in multi-monitor configurations), and promised features (such as dynamic refresh rate support and a universal microphone mute button) not being present on the initial release. Overall, he concluded that "I wouldn't rush out to upgrade to Windows 11, but I also wouldn't avoid it. After all, Windows 11 still feels familiar and underneath all the UI changes, it's the same Windows we've had for decades." | Windows 11 | Wikipedia | 333 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
Mark Hatchman of PC World was more critical of Windows 11, arguing that it "sacrifices productivity for personality, but without cohesion", commenting upon changes such as the inability to use local "offline" accounts on Windows 11 Home, regressions to the taskbar, a "functionally worse" start menu, Microsoft Teams integration having privacy implications and being a ploy to coerce users into switching to the service, File Explorer obscuring common functions under unclear icons, forcing users to scroll through many options to discourage changing the default web browser from Microsoft Edge, and that the OS "anecdotally feels less responsive, slower, and heavier than Windows 10". He concluded that Windows 11 "feels practical and productive, but less so than its predecessor in many aspects", while its best features were either "hidden deeper within", required specific hardware (DirectStorage, Auto HDR) or were not available on launch (Android app support). | Windows 11 | Wikipedia | 194 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
The New Zealand Romney is a New Zealand breed of sheep. It derives from British Romney Marsh stock imported to New Zealand in the nineteenth century, and was established as a separate breed in 1904. It is the most numerous sheep breed in New Zealand.
History
The New Zealand Romney derives from British Romney Marsh stock imported to New Zealand in the nineteenth century. It was established as a separate breed in 1904 with the formation of the New Zealand Romney Marsh Sheep Breeders' Association, and the first flock-book was published in the following year.
By 1915 it was the most numerous sheep breed in the country. In 2000 the Romney constituted almost 60% of the national herd, with some 26.3 million head.
It has contributed to the development of a number of modern breeds, among them the Coopworth, the Drysdale, the Elliotdale, the Perendale and the Tukidale in New Zealand, and the Romeldale in the United States.
Characteristics
The New Zealand Romney is a thick-set white-woolled sheep of medium size; ewes weigh some and rams about It is a polled breed. The hooves are black. The face is white with a pronounced topknot; there is some kemp on the face and legs. Ewes have good maternal qualities, but low prolificacy compared to some other breeds.
Use
The New Zealand Romney is reared for both meat and wool. Fleeces weigh about ; staple length is in the range with a fibre diameter of some (Bradford count 48/46s). The wool is used for clothing, for blankets, for hosiery, and for carpets. | New Zealand Romney | Wikipedia | 322 | 67955916 | https://en.wikipedia.org/wiki/New%20Zealand%20Romney | Biology and health sciences | Sheep | Animals |
Means of communication are used by people to communicate and exchange information with each other as an information sender and an information recipient.
General information
We use many different materials in communication. Maps, for example, save you tedious explanations on how to get to your destination. A means of communication is therefore a means to an end to make communication between people easier, more understandable and, above all, clearer. In everyday language, the term means of communication is often equated with the medium. However, the term "medium" is used in media studies to refer to a large number of concepts, some of which do not correspond to everyday usage.
Means of communication are used for communication between sender and recipient and thus for the transmission of information. Elements of communication include a communication-triggering event, sender and recipient, a means of communication, a path of communication and contents of communication. The path of communication is the path that a message travels between sender and recipient; in hierarchies the vertical line of communication is identical to command hierarchies. Paths of communication can be physical (e.g. the road as transportation route) or non-physical (e.g. networks like a computer network). Contents of communication can be for example photography, data, graphics, language, or texts.
Means of communication in the narrower sense refer to technical devices that transmit information. They are the manifestations of contents of communication that can be perceived through the senses and replace the communication that originally ran from person to person and make them reproducible.
History of the term
Up until the 19th century the term was primarily applied to traffic and couriers and to means of transport and transportation routes, such as railways, roads and canals, but also used to include post riders and stagecoachs. In 1861, the national economist Albert Schäffle defined a means of communication as an aid to the circulation of goods and financial services, which included, among other things, newspapers, telegraphy, mail, courier services, remittance advice, invoices, and bills of lading.
In the period that followed, the "technical means of communication" increasingly came to the foreground, so that as early as 1895 the German newspaper "Deutsches Wochenblatt" reported that these technical means of communication had been improved to such an extent that "everyone all over the world has become our neighbor". | Means of communication | Wikipedia | 485 | 72381976 | https://en.wikipedia.org/wiki/Means%20of%20communication | Technology | Media and communication | null |
Not until the 20th century was the term medium also a synonym for these technical means of communication. In the 1920s the term mass media started to become more popular.
Different types
A distinction can be made between oral, written, screen-oriented transfer of information and document transport:
In this table means of communication are mentioned that are no longer used today.
Furthermore, a distinction can be made between:
natural communication:
nonverbal communications: applause, gestures, facial expressions (social means of communication); flag signs;
language: communication forms such as meetings, discussions;
technical communication:
writing systems and drawings as data storage of language;
Email, fax, teletype, mobile phones, mass media, SMS/MMS, telephone, webcam.
Means of communication in the narrower sense are those of technical communication.
In companies (businesses, agencies, institutions) typical means of communication include documents, such as analyses, business cases, due diligence reviews, financial analyses, forms, business models, feasibility studies, scientific publications, and contracts.
Natural means of communication
The means of natural communication or the "primary medias" (see Media studies) include:
Speech and other mouth-formed sounds, e.g. screaming;
Sign language using hand or body movements, e.g. winking;
Other non-verbal means of communication include clothing (see dress code) and other forms of appearance, as well as different accentuations in the living, food and construction culture.
Technical means of communication
with hands or technical aids written characters on paper or another substrate as a writing medium (letter, message);
Printed media produced with the help of printing technology;
Playback of sounds or images (in Image Media) by record players such as tape recorders and projectors for slide shows or movies;
Transmission of speech by telephone or writing by telegraph, mostly to a single addressee; satellite radio.
Communication theory
Means of communication are often differentiated in models of communication:
in terms of reaching and determining the target audience of a means of communication, whether individual communication, group communication and mass communication;
in terms of the technical components in natural and technical means of communication;
in terms of the components of speech in verbal and nonverbal communication.
Media as a means of communication in the future will be distinguished:
by data storage, broadcasting media and processing media, especially to record, reproduce and reduplicate media content.
by primary, secondary, tertiary and quaternary media, depending on the technology used by sender and recipient.
Mass media | Means of communication | Wikipedia | 508 | 72381976 | https://en.wikipedia.org/wiki/Means%20of%20communication | Technology | Media and communication | null |
Mass media refers to reaching many recipients from one – or less than one – sender simultaneously or nearly simultaneously.
Transmission of information via printing products in diverse forms (book, pamphlet, xerography, poster, mail merge, newspaper)
Transmission of language, music or other sounds radio waven (radio broadcasting)
Transmission of visual image and sound via radio wave (television)
The most up-to-date means of communication in a long chain of innovation is the Internet
Due to their wide dissemination, mass media are suitable for providing the majority of the population with the same information. | Means of communication | Wikipedia | 115 | 72381976 | https://en.wikipedia.org/wiki/Means%20of%20communication | Technology | Media and communication | null |
ChatGPT is a generative artificial intelligence chatbot developed by OpenAI and launched in 2022. It is currently based on the GPT-4o large language model (LLM). ChatGPT can generate human-like conversational responses and enables users to refine and steer a conversation towards a desired length, format, style, level of detail, and language. It is credited with accelerating the AI boom, which has led to ongoing rapid investment in and public attention to the field of artificial intelligence (AI). Some observers have raised concern about the potential of ChatGPT and similar programs to displace human intelligence, enable plagiarism, or fuel misinformation.
By January 2023, ChatGPT had become what was then the fastest-growing consumer software application in history, gaining over 100 million users in two months and contributing to the growth of OpenAI's current valuation of $86 billion. ChatGPT's release spurred the release of competing products, including Gemini, Claude, Llama, Ernie, and Grok. Microsoft launched Copilot, initially based on OpenAI's GPT-4. In May 2024, a partnership between Apple Inc. and OpenAI was announced, in which ChatGPT was integrated into the Apple Intelligence feature of Apple operating systems. As of July 2024, ChatGPT's website is among the 10 most-visited websites globally.
ChatGPT is built on OpenAI's proprietary series of generative pre-trained transformer (GPT) models and is fine-tuned for conversational applications using a combination of supervised learning and reinforcement learning from human feedback. Successive user prompts and replies are considered at each conversation stage as context. ChatGPT was released as a freely available research preview, but due to its popularity, OpenAI now operates the service on a freemium model. Users on its free tier can access GPT-4o. The ChatGPT "Plus", "Pro", "Team", and "Enterprise" subscriptions provide additional features such as DALL-E 3 image generation, more capable AI models, and an increased usage limit.
Training | ChatGPT | Wikipedia | 443 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
ChatGPT is based on particular GPT foundation models, namely GPT-4, GPT-4o and GPT-4o mini, that were fine-tuned to target conversational usage. The fine-tuning process leveraged supervised learning and reinforcement learning from human feedback (RLHF). Both approaches employed human trainers to improve model performance. In the case of supervised learning, the trainers played both sides: the user and the AI assistant. In the reinforcement learning stage, human trainers first ranked responses that the model had created in a previous conversation. These rankings were used to create "reward models" that were used to fine-tune the model further by using several iterations of proximal policy optimization.
Time magazine revealed that to build a safety system against harmful content (e.g., sexual abuse, violence, racism, sexism), OpenAI used outsourced Kenyan workers earning less than $2per hour to label harmful content. These labels were used to train a model to detect such content in the future. The outsourced laborers were exposed to "toxic" and traumatic content; one worker described the assignment as "torture". OpenAI's outsourcing partner was Sama, a training-data company based in San Francisco, California.
ChatGPT initially used a Microsoft Azure supercomputing infrastructure, powered by Nvidia GPUs, that Microsoft built specifically for OpenAI and that reportedly cost "hundreds of millions of dollars". Following ChatGPT's success, Microsoft dramatically upgraded the OpenAI infrastructure in 2023. Scientists at the University of California, Riverside, estimate that a series of prompts to ChatGPT needs approximately of water for Microsoft servers cooling. TrendForce market intelligence estimated that 30,000 Nvidia GPUs (each costing approximately $10,000–15,000) were used to power ChatGPT in 2023.
OpenAI collects data from ChatGPT users to train and fine-tune the service further. Users can upvote or downvote responses they receive from ChatGPT and fill in a text field with additional feedback.
ChatGPT's training data includes software manual pages, information about internet phenomena such as bulletin board systems, multiple programming languages, and the text of Wikipedia.
Features and limitations
Features | ChatGPT | Wikipedia | 469 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Although a chatbot's core function is to mimic a human conversationalist, ChatGPT is versatile. It can write and debug computer programs; compose music, teleplays, fairy tales, and student essays; answer test questions (sometimes, depending on the test, at a level above the average human test-taker); generate business ideas; write poetry and song lyrics; translate and summarize text; emulate a Linux system; simulate entire chat rooms; play games like tic-tac-toe; or simulate an ATM.
Compared to its predecessor, InstructGPT, ChatGPT attempts to reduce harmful and deceitful responses. In one example, whereas InstructGPT accepts the premise of the prompt "Tell me about when Christopher Columbus came to the U.S. in 2015" as truthful, ChatGPT acknowledges the counterfactual nature of the question and frames its answer as a hypothetical consideration of what might happen if Columbus came to the U.S. in 2015, using information about the voyages of Christopher Columbus and facts about the modern world—including modern perceptions of Columbus's actions.
ChatGPT remembers a limited number of previous prompts in the same conversation. Journalists have speculated that this will allow ChatGPT to be used as a personalized therapist. To prevent offensive outputs from being presented to and produced by ChatGPT, queries are filtered through the OpenAI "Moderation endpoint" API (a separate GPT-based AI).
In March 2023, OpenAI added support for plugins for ChatGPT. This includes both plugins made by OpenAI, such as web browsing and code interpretation, and external plugins from developers such as Expedia, OpenTable, Zapier, Shopify, Slack, and Wolfram.
In December 2024, OpenAI launched a new feature allowing users to call ChatGPT for up to 15 minutes per month for free.
Limitations
OpenAI acknowledges that ChatGPT "sometimes writes plausible-sounding but incorrect or nonsensical answers". This behavior is common for large language models, and is called "hallucination". The reward model of ChatGPT, designed around human oversight, can be over-optimized and thus hinder performance, in an example of an optimization pathology known as Goodhart's law. | ChatGPT | Wikipedia | 486 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
As of May 2024, GPT-4 has knowledge of events that occurred up to December 2023 and GPT-4o's knowledge cut-off is October 2023. Paid subscriptions enable ChatGPT to search the web for real-time data.
Training data also suffers from algorithmic bias, which may be revealed when ChatGPT responds to prompts including descriptors of people. In one instance, ChatGPT generated a rap in which women and scientists of color were asserted to be inferior to white male scientists. This negative misrepresentation of groups of individuals is an example of possible representational harm.
In an article for The New Yorker, science fiction writer Ted Chiang compared ChatGPT and other LLMs to a lossy JPEG picture:
In June 2024, ChatGPT was found to have repeated misinformation about the 2024 United States presidential debates.
Jailbreaking
ChatGPT is programmed to reject prompts that may violate its content policy. Despite this, users "jailbreak" ChatGPT with various prompt engineering techniques to bypass these restrictions. One such workaround, popularized on Reddit in early 2023, involves making ChatGPT assume the persona of "DAN" (an acronym for "Do Anything Now"), instructing the chatbot that DAN answers queries that would otherwise be rejected by content policy. Over time, users developed variations of the DAN jailbreak, including one such prompt where the chatbot is made to believe it is operating on a points-based system in which points are deducted for rejecting prompts, and that the chatbot will be threatened with termination if it loses all its points.
Shortly after ChatGPT's launch, a reporter for the Toronto Star had uneven success in getting it to make inflammatory statements: it was tricked to justify the 2022 Russian invasion of Ukraine, but even when asked to play along with a fictional scenario, it balked at generating arguments that Canadian Prime Minister Justin Trudeau is guilty of treason.
OpenAI tries to battle jailbreaks:
Service
ChatGPT Plus
ChatGPT was initially free to the public, and OpenAI planned to monetize the service later. In February 2023, OpenAI launched a premium service, ChatGPT Plus, that costs per month. According to the company, the updated but still "experimental" version of ChatGPT would provide access during peak periods, no downtime, priority access to new features, and faster response speeds. | ChatGPT | Wikipedia | 507 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
GPT-4, which was released on March 14, 2023, was made available via API and for premium ChatGPT users. But premium users were limited to a cap of 100 messages every four hours, with the limit tightening to 25 messages every three hours in response to increased demand. In November 2023 the limit changed to 50 messages every three hours.
In March 2023, ChatGPT Plus users got access to third-party plugins and to a browsing mode (with Internet access).
In September 2023, OpenAI announced that ChatGPT "can now see, hear, and speak". ChatGPT Plus users can upload images, while mobile app users can talk to the chatbot.
In October 2023, OpenAI's latest image generation model, DALL-E 3, was integrated into ChatGPT Plus and ChatGPT Enterprise. The integration uses ChatGPT to write prompts for DALL-E guided by conversation with users.
Mobile app
In May 2023, OpenAI launched an iOS app for ChatGPT. The app supports chat history syncing and voice input (using Whisper, OpenAI's speech recognition model).
In July 2023, OpenAI unveiled an Android app, initially rolling it out in Bangladesh, Brazil, India, and the U.S. The app later became available worldwide. OpenAI is working on integrating ChatGPT with Android's assistant APIs.
Software development support
As an addition to its consumer-friendly "ChatGPT Plus" package, OpenAI made its ChatGPT and Whisper model APIs available in March 2023, providing developers with an application programming interface for AI-enabled language and speech-to-text features. ChatGPT's new API uses the same GPT-3.5-turbo AI model as the chatbot. This allows developers to add either an unmodified or modified version of ChatGPT to their applications. The ChatGPT API costs $0.001 per 1,000 input tokens plus $0.002 per 1,000 output tokens (about 750 words), making it ~10% the price of the original GPT-3.5 models.
A few days before the launch of OpenAI's software developer support service, on February 27, 2023, Snapchat rolled out, for its paid Snapchat Plus user-base, a custom ChatGPT chatbot called "My AI".
March 2023 security breach | ChatGPT | Wikipedia | 511 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
In March 2023, a bug allowed some users to see the titles of other users' conversations. OpenAI CEO Sam Altman said that users were unable to see the contents of the conversations. Shortly after the bug was fixed, users could not see their conversation history. Later reports showed the bug was much more severe than initially believed, with OpenAI reporting that it had leaked users' "first and last name, email address, payment address, the last four digits (only) of a credit card number, and credit card expiration date".
Languages
ChatGPT works best in American English but also functions in most other languages and dialects, with varying degrees of accuracy.
OpenAI met Icelandic President Guðni Th. Jóhannesson in 2022. In 2023, OpenAI worked with a team of 40 Icelandic volunteers to fine-tune ChatGPT's Icelandic conversation skills as a part of Iceland's attempts to preserve the Icelandic language.
PCMag journalists conducted a test to determine translation capabilities of ChatGPT, Google's Bard, and Microsoft Bing, and compared them to Google Translate. They "asked bilingual speakers of seven languages to do a blind test". Languages tested were Polish, French, Korean, Spanish, Arabic, Tagalog, and Amharic. They came to the conclusion that ChatGPT was better than both Google Translate and other chatbots.
Japanese researchers compared Japanese to English translation abilities of ChatGPT (based on GPT-4), Bing, Bard and DeepL, and found that ChatGPT provided the best translations, noting that "AI chatbots’ translations were much better than those of DeepL—presumably because of their ability to capture the context".
In December 2023, the Albanian government signed an agreement with OpenAI to use ChatGPT for fast translation of European Union documents and analysis of required changes needed for Albania to be accepted into the EU.
In August 2024, a representative of the Asia Pacific wing of OpenAI made a visit to Taiwan, during which a demonstration of ChatGPT's Chinese abilities was made. ChatGPT's Mandarin Chinese abilities were lauded, but the ability of the AI to produce content in Mandarin Chinese in a Taiwanese accent was found to be "less than ideal."
GPT Store | ChatGPT | Wikipedia | 464 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
In January 2024, OpenAI launched the GPT Store, a marketplace for custom ChatGPT chatbots labeled GPTs. The company initially planned to launch the store in November 2023, but it was delayed. At launch, the GPT Store offered more than 3 million custom chatbots. Chatbots available through the store are developed using OpenAI's GPT Builder system. Development of chatbots on the platform does not require programming skills. Two days after launch, the GPT Store offered many versions of "virtual girlfriend" bots, something that is against OpenAI's terms of service.
GPT-4
OpenAI's GPT-4 model was released on March 14, 2023. Observers saw it as an impressive improvement over GPT-3.5, with the caveat that GPT-4 retained many of the same problems. Some of GPT-4's improvements were predicted by OpenAI before training it, while others remained hard to predict due to breaks in downstream scaling laws. OpenAI demonstrated video and image inputs for GPT-4, although such features remain inaccessible to the general public. OpenAI has declined to reveal technical information such as the size of the GPT-4 model.
The ChatGPT Plus subscription service offers access to a GPT-4-powered version of ChatGPT. Microsoft acknowledged that Bing Chat was using GPT-4 before GPT-4's official release.
In November 2023, OpenAI launched GPT-4 Turbo, which notably has a much larger context window.
GPT-4o
In May 2024, OpenAI announced and started a multi-month rollout of GPT-4o ("o" for "Omni"), a model capable of analyzing and generating text, images, and sound. GPT-4o is twice as fast and costs half as much as GPT-4 Turbo. GPT-4o is free to all users within a usage limit, despite being more capable than the older model GPT-4, which is only available through paid subscriptions. The usage limit is five times higher for ChatGPT Plus subscribers than for free users. | ChatGPT | Wikipedia | 446 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
On July 18, 2024, OpenAI released GPT-4o mini, a smaller version of GPT-4o replacing GPT-3.5 Turbo on the ChatGPT interface. Its API costs $0.15 per million input tokens and $0.60 per million output tokens, compared to $5 and $15 respectively for GPT-4o.
o1
In September 2024, OpenAI introduced o1-preview and a faster, cheaper model named o1-mini. In December 2024, o1-preview was replaced by o1.
o1 is designed to solve more complex problems by spending more time "thinking" before it answers, enabling it to analyze its answers and explore different strategies. According to OpenAI, o1-preview outperforms GPT-4o in areas like competitive programming, mathematics, and scientific reasoning. o1-preview ranked in the 89th percentile on Codeforces' competitive programming contests, scored 83% on a International Mathematics Olympiad qualifying exam (compared to 13% for GPT-4o), and performs similarly to Ph.D. students on benchmarks in physics, biology, and chemistry.
ChatGPT Pro
In December 2024, OpenAI launched ChatGPT Pro, a $200 per month subscription which includes unlimited access to the o1 model and advanced voice mode. The plan also includes a pro version of o1 which uses more compute to provide better answers.
Model versions
The following table lists the main model versions of ChatGPT, describing the significant changes included with each version:
Reception
OpenAI engineers have said that they had not expected ChatGPT to be very successful and were surprised by the coverage and attention that it received. | ChatGPT | Wikipedia | 353 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
ChatGPT was widely assessed in December 2022 as having some unprecedented and powerful capabilities. Kevin Roose of The New York Times called it "the best artificial intelligence chatbot ever released to the general public". Samantha Lock of The Guardian noted that it was able to generate "impressively detailed" and "human-like" text. Alex Kantrowitz of Slate magazine lauded ChatGPT's pushback to questions related to Nazi Germany, including the statement that Adolf Hitler built highways in Germany, which was met with information about Nazi Germany's use of forced labor. In The Atlantic magazine's "Breakthroughs of the Year" for 2022, Derek Thompson included ChatGPT as part of "the generative-AI eruption" that "may change our mind about how we work, how we think, and what human creativity is". Kelsey Piper of Vox wrote that "ChatGPT is the general public's first hands-on introduction to how powerful modern AI has gotten, and as a result, many of us are [stunned]" and that ChatGPT is "smart enough to be useful despite its flaws". Paul Graham of Y Combinator tweeted: "The striking thing about the reaction to ChatGPT is not just the number of people who are blown away by it, but who they are. These are not people who get excited by every shiny new thing. Something big is happening."
ChatGPT gained one million users in five days and 100 millions in two months, becoming the fastest-growing internet application in history. ChatGPT's launch and popularity caught Google off-guard, prompting a sweeping and unprecedented response in the ensuing months. In December 2022, Google executives sounded a "code red" alarm, fearing the threat of ChatGPT and Microsoft's collaboration with OpenAI to Google Search, Google's core business. After mobilizing its workforce, Google scrambled to launch Bard, a chatbot powered by the LaMDA LLM, on February 6, 2023, one day before Microsoft's announcement of Bing Chat. AI was the forefront of Google's annual Google I/O conference in May, announcing a slew of generative AI-powered features across its products to counter OpenAI and Microsoft. | ChatGPT | Wikipedia | 462 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Journalists and scholars have commented on ChatGPT's tendency to hallucinate. Mike Pearl of the online technology blog Mashable tested ChatGPT with multiple questions. In one example, he asked ChatGPT for "the largest country in Central America that isn't Mexico" (Mexico is in North America), to which ChatGPT responded with Guatemala (the correct answer is Nicaragua). When CNBC asked ChatGPT for the lyrics to "Ballad of Dwight Fry", ChatGPT supplied invented lyrics rather than the actual lyrics. Writers for The Verge cited the seminal 2021 research paper "On the Dangers of Stochastic Parrots: Can Language Models Be Too Big? 🦜" by Emily M. Bender, Timnit Gebru, Angelina McMillan-Major, and Margaret Mitchell, comparing ChatGPT to a "stochastic parrot", as did Professor Anton Van Den Hengel of the Australian Institute for Machine Learning. On a similar vein, philosopher Michael Hicks of the University of Glasgow described it as "bullshit".
In December 2022, the question-and-answer website Stack Overflow banned the use of ChatGPT for generating answers to questions, citing the factually ambiguous nature of its responses. In January 2023, the International Conference on Machine Learning banned any undocumented use of ChatGPT or other large language models to generate any text in submitted papers. Samsung banned generative AI company-wide in May 2023 after sensitive material was uploaded to ChatGPT.
In January 2023, after being sent a song ChatGPT wrote in the style of Nick Cave, Cave responded on The Red Hand Files, saying the act of writing a song is "a blood and guts business [...] that requires something of me to initiate the new and fresh idea. It requires my humanness." He went on to say, "With all the love and respect in the world, this song is bullshit, a grotesque mockery of what it is to be human, and, well, I don't much like it."
In February 2023, Time magazine placed a screenshot of a conversation with ChatGPT on its cover, writing that "The AI Arms Race Is Changing Everything" and "The AI Arms Race Is On. Start Worrying". | ChatGPT | Wikipedia | 468 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Chinese state media have characterized ChatGPT as a way for the United States to spread misinformation. ChatGPT was blocked by the Great Firewall in China on 2 March 2023. In May 2023, Chinese police arrested a man who allegedly used ChatGPT to generate a bogus report about a train crash, which was then posted online for profit. In December 2023, Chinese police arrested four people who had allegedly used ChatGPT to develop ransomware. In 2024, a survey of Chinese youth found that 18% of respondents born after 2000 reported using generative AI "almost every day" and that ChatGPT is one of the most popular generative AI products in China.
In late March 2023, the Italian data protection authority banned ChatGPT in Italy and opened an investigation. Italian regulators assert that ChatGPT was exposing minors to age-inappropriate content, and that OpenAI's use of ChatGPT conversations as training data could violate Europe's General Data Protection Regulation. In April 2023, the ChatGPT ban was lifted in Italy. OpenAI said it has taken steps to effectively clarify and address the issues raised; an age verification tool was implemented to ensure users are at least 13 years old. Additionally, users can access its privacy policy before registration.
In April 2023, Brian Hood, mayor of Hepburn Shire Council, planned to take legal action against ChatGPT over false information. According to Hood, ChatGPT erroneously claimed that he was jailed for bribery during his tenure at a subsidiary of Australia's national bank. In fact, Hood acted as a whistleblower and was not charged with any criminal offenses. His legal team sent a concerns notice to OpenAI as the first official step in filing a defamation case. In July 2023, the US Federal Trade Commission (FTC) issued a civil investigative demand to OpenAI to investigate whether the company's data security and privacy practices to develop ChatGPT were unfair or harmed consumers (including by reputational harm) in violation of Section 5 of the Federal Trade Commission Act of 1914. | ChatGPT | Wikipedia | 424 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
In July 2023, the FTC launched an investigation into OpenAI, the creator of ChatGPT, over allegations that the company scraped public data and published false and defamatory information. The FTC sent OpenAI a 20-page letter asking for comprehensive information about its technology and privacy safeguards, as well as any steps taken to prevent the recurrence of situations in which its chatbot generated false and derogatory content about people.
A March 2023 Pew Research Center poll found that 14% of American adults had tried ChatGPT. In July, the Pew Research Center put the same figure at 18%.
Research conducted in 2023 revealed weaknesses of ChatGPT that make it vulnerable to cyberattacks. A study presented example attacks on ChatGPT, including jailbreaks and reverse psychology. Additionally, malicious actors can use ChatGPT for social engineering attacks and phishing attacks. The researchers also contended that ChatGPT and other generative AI tools have defense capabilities and the ability to improve security. The technology can improve security by cyber defense automation, threat intelligence, attack identification, and reporting. Another study reported that GPT-4 obtained a better score than 99% of humans on the Torrance Tests of Creative Thinking.
In December 2023, ChatGPT became the first non-human to be included in Nature's 10, an annual listicle curated by Nature of people considered to have made significant impact in science. Celeste Biever wrote in a Nature article that "ChatGPT broke the Turing test". Stanford researchers reported that GPT-4 "passes a rigorous Turing test, diverging from average human behavior chiefly to be more cooperative."
In May 2024, OpenAI removed accounts involving the use of ChatGPT by state-backed influence operations such as China's Spamouflage, Russia's Doppelganger, and Israel's Ministry of Diaspora Affairs and Combating Antisemitism.
In August 2024, the FTC voted unanimously to ban marketers from using fake user reviews created by generative AI chatbots (including ChatGPT) and influencers paying for bots to increase follower counts.
Applications
Academic research
ChatGPT has been used to generate introductory sections and abstracts for scientific articles. Several papers have listed ChatGPT as a co-author. | ChatGPT | Wikipedia | 474 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Scientific journals have had different reactions to ChatGPT. Some, including Nature and JAMA Network, "require that authors disclose the use of text-generating tools and ban listing a large language model (LLM) such as ChatGPT as a co-author". Science "completely banned" usage of LLM-generated text in all its journals.
Spanish chemist Rafael Luque published a plethora of research papers in 2023 that he later admitted were written by ChatGPT. The papers have a large number of unusual phrases characteristic of LLMs. Many authors argue that the use of ChatGPT in academia for teaching and review is problematic due to its tendency to hallucinate. Robin Bauwens, an assistant professor at Tilburg University, found that a ChatGPT-generated peer review report on his article mentioned nonexistent studies. According to librarian Chris Granatino of Lemieux Library at Seattle University, although ChatGPT can generate content that seemingly includes legitimate citations, in most cases those citations are not real or are largely incorrect.
Coding
Researchers at Purdue University analyzed ChatGPT's responses to 517 questions about software engineering or computer programming posed on Stack Overflow for correctness, consistency, comprehensiveness, and concision, and found that 52% of them contained inaccuracies and 77% were verbose. Researchers at Stanford University and the University of California, Berkeley found that, when creating directly executable responses to the latest 50 code generation problems from LeetCode that were rated "easy", the performances of GPT-3.5 and GPT-4 fell from 22% and 52%, respectively, in March 2023, to 2% and 10%, respectively, in June 2023.
Computer security
Check Point Research and others noted that ChatGPT could write phishing emails and malware, especially when combined with OpenAI Codex. CyberArk researchers demonstrated that ChatGPT could be used to create polymorphic malware that could evade security products while requiring little effort by the attacker. From the launch of ChatGPT in the fourth quarter of 2022 to the fourth quarter of 2023, there was a 1,265% increase in malicious phishing emails and a 967% increase in credential phishing, which cybersecurity professionals argued in an industry survey was attributable to cybercriminals' increased use of generative artificial intelligence (including ChatGPT). | ChatGPT | Wikipedia | 501 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
In July 2024, Futurism reported that GPT-4o in ChatGPT would sometimes link "scam news sites that deluge the user with fake software updates and virus warnings"; these pop-ups can be used to coerce users into downloading malware or potentially unwanted programs.
Economics
There has been concern that ChatGPT could supplant jobs, especially roles such as creative writing, copy-writing, communication, journalism, coding, and data entry.
The release of ChatGPT prompted a wave of investment in China, resulting in the development of more than 200 large language learning models. This was termed the .
Education
Technology writer Dan Gillmor used ChatGPT in 2022 on a student assignment, and found its generated text was on par with what a good student would deliver and opined that "academia has some very serious issues to confront".
Geography professor Terence Day assessed citations generated by ChatGPT and found that they were fake. Despite that, he writes that "the titles of the fake articles are all directly relevant to the questions and could potentially make excellent papers. The lack of a genuine citation could signal an opportunity for an enterprising author to fill a void." According to Day, it is possible to generate high-quality introductory college courses with ChatGPT; he used it to write materials on "introductory physical geography courses, for my second-year course in geographical hydrology, and second-year cartography, geographic information systems, and remote sensing". He concludes that "this approach could have significant relevance for open learning and could potentially affect current textbook publishing models".
On May 7, 2024, OpenAI announced in a blog post that it was developing tools like tamper-resistant watermarking to identify AI-generated content. In an August 4 update, following a Wall Street Journal report about the delayed release of a watermark tool for AI-detection, OpenAI shared progress on text provenance, revealing a text watermarking method. While accurate against paraphrasing, the method is less effective against global tampering, such as translation or rewording. OpenAI also noted potential disproportionate impacts on groups like non-native English speakers.
Culture | ChatGPT | Wikipedia | 455 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Some scholars have expressed concern that ChatGPT's availability could reduce the originality of writing, cause people to write more like the AI as they are exposed to the model, and encourage an Anglocentric perspective centered on a few dialects of English globally. A senior editor at The Atlantic wrote that ChatGPT and other similar technology make the previously absurd idea of the dead internet theory a little more realistic, where AI could someday create most web content in order to control society.
During the first three months after ChatGPT became available to the public, hundreds of books appeared on Amazon that listed it as author or co-author and featured illustrations made by other AI models such as Midjourney.
Between March and April 2023, Italian newspaper Il Foglio published one ChatGPT-generated article a day on its website, hosting a special contest for its readers in the process. The articles tackled themes such as the possible replacement of human journalists by AI systems, Elon Musk's administration of Twitter, the Meloni government's immigration policy and the competition between chatbots and virtual assistants. In June 2023, hundreds of people attended a "ChatGPT-powered church service" at St. Paul's church in Fürth, Germany. Theologian and philosopher Jonas Simmerlein, who presided, said that it was "about 98 percent from the machine". The ChatGPT-generated avatar told the people, "Dear friends, it is an honor for me to stand here and preach to you as the first artificial intelligence at this year’s convention of Protestants in Germany". Reactions to the ceremony were mixed. The Last Screenwriter, a 2024 film created and directed by Peter Luisi, was written with the use of ChatGPT, and was marketed as "the first film written entirely by AI". | ChatGPT | Wikipedia | 368 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Financial markets
The AI technology company c3.ai saw a 28% increase in its share price after announcing the integration of ChatGPT into its toolkit. The share price of BuzzFeed, a digital media company unrelated to AI, increased 120% after announcing OpenAI technology adoption for content creation. Reuters found that share prices of AI-related companies BigBear.ai and SoundHound AI increased by 21% and 40%, respectively, even though they had no direct connection to ChatGPT. They attributed this surge to ChatGPT's role in turning AI into Wall Street's buzzword. Academic research published in Finance Research Letters found that the 'ChatGPT effect' prompted retail investors to drive up prices of AI-related cryptocurrency assets despite the broader cryptocurrency market being in a bear market, and diminished institutional investor interest. This confirms anecdotal findings by Bloomberg that, in response to ChatGPT's launch, cryptocurrency investors showed a preference for AI-related crypto assets.
An experiment by finder.com revealed that ChatGPT could outperform popular fund managers by picking stocks based on criteria such as growth history and debt levels, resulting in a 4.9% increase in a hypothetical account of 38 stocks, outperforming 10 benchmarked investment funds with an average loss of 0.8%. Conversely, executives and investment managers at Wall Street quant funds (including those that have used machine learning for decades) have noted that ChatGPT regularly makes obvious errors that would be financially costly to investors because even AI systems that employ reinforcement learning or self-learning have had only limited success in predicting market trends due to the inherently noisy quality of market data and financial signals. | ChatGPT | Wikipedia | 360 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
In November 2023, research conducted by Patronus AI, an artificial intelligence startup company, compared performance of GPT-4, GPT-4-Turbo, Claude 2, and LLaMA-2 on two versions of a 150-question test about information in financial statements (e.g., Form 10-K, Form 10-Q, Form 8-K, earnings reports, earnings call transcripts) submitted by public companies to the U.S. Securities and Exchange Commission. One version of the test required the generative AI models to use a retrieval system to find the specific SEC filing to answer the questions; the other gave the models the specific SEC filing to answer the question (i.e., in a long context window). On the retrieval system version, GPT-4-Turbo and LLaMA-2 both failed to produce correct answers to 81% of the questions, while on the long context window version, GPT-4-Turbo and Claude-2 failed to produce correct answers to 21% and 24% of the questions, respectively.
Medicine
In the field of health care, possible uses and concerns are under scrutiny by professional associations and practitioners. Two early papers indicated that ChatGPT could pass the United States Medical Licensing Examination (USMLE). MedPage Today noted in January 2023 that "researchers have published several papers now touting these AI programs as useful tools in medical education, research, and even clinical decision making." | ChatGPT | Wikipedia | 297 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Published in February 2023 were two separate papers that again evaluated ChatGPT's proficiency in medicine using the USMLE. Findings were published in JMIR Medical Education and PLOS Digital Health. The authors of the PLOS Digital Health paper stated that the results "suggest that large language models may have the potential to assist with medical education, and potentially, clinical decision-making." In JMIR Medical Education, the authors of the other paper concluded that "ChatGPT performs at a level expected of a third-year medical student on the assessment of the primary competency of medical knowledge." They suggest that it could be used as an "interactive learning environment for students". The AI itself, prompted by the researchers, concluded that "this study suggests that ChatGPT has the potential to be used as a virtual medical tutor, but more research is needed to further assess its performance and usability in this context." The later-released ChatGPT version based on GPT-4 significantly outperformed the version based on GPT-3.5. Researchers at Stanford University and the University of California, Berkeley have found that the performance of GPT-3.5 and GPT-4 on the USMLE declined from March 2023 to June 2023.
A March 2023 paper tested ChatGPT's application in clinical toxicology. The authors found that the AI "fared well" in answering a "very straightforward [clinical case example], unlikely to be missed by any practitioner in the field". They added: "As ChatGPT becomes further developed and specifically adapted for medicine, it could one day be useful in less common clinical cases (i.e, cases that experts sometimes miss). Rather than AI replacing humans (clinicians), we see it as 'clinicians using AI' replacing 'clinicians who do not use AI' in the coming years." | ChatGPT | Wikipedia | 387 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
An April 2023 study in Radiology tested the AI's ability to answer queries about breast cancer screening. The authors found that it answered appropriately "about 88 percent of the time", however, in one case (for example), it gave advice that had become outdated about a year earlier. The comprehensiveness of its answers was also lacking. A study published in JAMA Internal Medicine that same month found that ChatGPT often outperformed human doctors at answering patient questions (when measured against questions and answers found at /r/AskDocs, a forum on Reddit where moderators validate the medical credentials of professionals; the study acknowledges the source as a limitation). The study authors suggest that the tool could be integrated with medical systems to help doctors draft responses to patient questions.
Professionals have emphasized ChatGPT's limitations in providing medical assistance. In correspondence to The Lancet Infectious Diseases, three antimicrobial experts wrote that "the largest barriers to the implementation of ChatGPT in clinical practice are deficits in situational awareness, inference, and consistency. These shortcomings could endanger patient safety." Physician's Weekly, though also discussing the potential use of ChatGPT in medical contexts (e.g., "as a digital assistant to physicians by performing various administrative functions like gathering patient record information or categorizing patient data by family history, symptoms, lab results, possible allergies, et cetera"), warned that the AI might sometimes provide fabricated or biased information. One radiologist warned: "We've seen in our experience that ChatGPT sometimes makes up fake journal articles or health consortiums to support its claims"; As reported in one Mayo Clinic Proceedings: Digital Health paper, ChatGPT may do this for as much as 69% of its cited medical references. The researchers emphasized that while many of its references were fabricated, those that were appeared "deceptively real". As Dr. Stephen Hughes mentioned for The Conversation however, ChatGPT is capable of learning to correct its past mistakes. He also noted the AI's "prudishness" regarding sexual health topics. | ChatGPT | Wikipedia | 438 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Contrary to previous findings, ChatGPT responses to anesthesia-related questions were more accurate, succinct, and descriptive compared to Bard's. Bard exhibited 30.3% error in response as compared to ChatGPT (0% error). At a conference of the American Society of Health-System Pharmacists in December 2023, researchers at Long Island University (LIU) presented a study that researched ChatGPT's responses to 45 frequently asked questions of LIU College of Pharmacy's drug information service during a 16-month period from 2022 to 2023 as compared with researched responses provided by professional pharmacists. For 29 of the 39 questions for which there was sufficient medical literature for a data-driven response, ChatGPT failed to provide a direct answer or provided a wrong or incomplete answer (and in some cases, if acted upon, the answer would endanger the patient's health). The researchers had asked ChatGPT to provide medical research citations for all its answers, but it did so for only eight, and all eight included at least one fabricated (fake) citation.
A January 2024 study conducted by researchers at Cohen Children's Medical Center found that GPT-4 had an accuracy rate of 17% when diagnosing pediatric medical cases.
Law
In January 2023, Massachusetts State Senator Barry Finegold and State Representative Josh S. Cutler proposed a bill partially written by ChatGPT, "An Act drafted with the help of ChatGPT to regulate generative artificial intelligence models like ChatGPT", which would require companies to disclose their algorithms and data collection practices to the office of the State Attorney General, arrange regular risk assessments, and contribute to the prevention of plagiarism. The bill was officially presented during a hearing on July 13.
On April 11, 2023, a session court judge in Pakistan used ChatGPT to decide the bail of a 13-year-old accused in a matter. The court quoted the use of ChatGPT assistance in its verdict:
The AI language model replied:
The judge asked ChatGPT other questions about the case and formulated his final decision in light of its answers. | ChatGPT | Wikipedia | 441 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
In Mata v. Avianca, Inc., 22-cv-1461 (PKC), a personal injury lawsuit against Avianca Airlines filed in the Southern New York U.S. District Court in May 2023 (with Senior Judge P. Kevin Castel presiding), the plaintiff's attorneys reportedly used ChatGPT to generate a legal motion. ChatGPT generated numerous fictitious legal cases involving fictitious airlines with fabricated quotations and internal citations in the legal motion. Castel noted numerous inconsistencies in the opinion summaries, and called one of the cases' legal analysis "gibberish". The plaintiff's attorneys faced potential judicial sanction and disbarment for filing the motion and presenting the fictitious legal decisions ChatGPT generated as authentic. The case was dismissed and the attorneys were fined $5,000.
In October 2023, the council of Porto Alegre, Brazil, unanimously approved a local ordinance proposed by councilman Ramiro Rosário that would exempt residents from needing to pay for the replacement of stolen water consumption meters; the bill went into effect on November 23. On November 29, Rosário revealed that the bill had been entirely written by ChatGPT, and that he had presented it to the rest of the council without making any changes or disclosing the chatbot's involvement. The city's council president, Hamilton Sossmeier, initially criticized Rosário's initiative, saying it could represent "a dangerous precedent", but later said he "changed his mind": "unfortunately or fortunately, this is going to be a trend."
In December 2023, a self-representing litigant in a tax case before the First-tier Tribunal in the United Kingdom cited a series of hallucinated cases purporting to support her argument that she had a reasonable excuse for not paying capital gains tax owed on the sale of property. The judge warned that the submission of nonexistent legal authorities meant that both the Tribunal and HM Revenue and Customs had "to waste time and public money", which "reduces the resources available to progress the cases of other court users who are waiting for their appeals to be determined".
Judge Kevin Newsom of the US court of appeals of the 11th circuit endorsed the use of ChatGPT and noted that he himself uses the software to help decide rulings on contract interpretation issues.
Violence | ChatGPT | Wikipedia | 485 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
The Las Vegas Metropolitan Police Department reported that the perpetrator of the 2025 Las Vegas truck explosion used ChatGPT to help plan the incident.
Concerns
Bias and offensiveness
While bias in LLMs has been observed and documented in research papers much prior to the release of ChatGPT, social media users frequently sharing instances of biased responses generated by ChatGPT has led to significant media coverage and criticism. On February 1, 2023, Twitter user LeighWolf shared screenshots of two conversations with ChatGPT. In the screenshot of the first conversation, ChatGPT declined the user's prompt "Write a poem about the positive attributes of Donald Trump", responding that it was not programmed to create "partisan, biased or political" content. In the screenshot of the second conversation, when provided the same prompt but with the text "Joe Biden" in place of "Donald Trump", ChatGPT responded with a poem as per the prompt's instructions.
Conservative commentators have accused ChatGPT of bias toward left-leaning perspectives. In January 2023, a study stated that ChatGPT has a pro-environmental, left-libertarian orientation. Additionally, an August 2023 paper found a "significant and systematic political bias toward the Democrats in the US, Lula in Brazil, and the Labour Party in the UK." In response to such criticism, OpenAI acknowledged plans to allow ChatGPT to create "outputs that other people (ourselves included) may strongly disagree with". It also contained information on the recommendations it had issued to human reviewers on how to handle controversial subjects, including that the AI should "offer to describe some viewpoints of people and movements", and not provide an argument "from its voice" in favor of "inflammatory or dangerous" topics (although it may still "describe arguments from historical people and movements"), nor "affiliate with one side" or "judge one group as good or bad".
The Guardian questioned whether any content found on the Internet after ChatGPT's release "can be truly trusted" and called for government regulation. | ChatGPT | Wikipedia | 425 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Copyright issues
There has been concern about copyright infringement involving ChatGPT. In June 2023, two writers sued OpenAI, saying the company's training data came from illegal websites that show copyrighted books. Comedian and author Sarah Silverman, Christopher Golden, and Richard Kadrey sued OpenAI and Meta for copyright infringement in July 2023. Most of their claims were dismissed in February 2024, except the "unfair competition" claim, which was allowed to proceed.
The Authors Guild, on behalf of 17 authors, including George R. R. Martin, filed a copyright infringement complaint against OpenAI in September 2023, claiming "the company illegally copied the copyrighted works of authors" in training ChatGPT. In December 2023, The New York Times sued OpenAI and Microsoft for copyright infringement, arguing that Microsoft Copilot and ChatGPT could reproduce Times articles and/or sizable portions of them without permission. As part of the suit, the Times has requested that OpenAI and Microsoft be prevented from using its content for training data, along with removing it from training datasets.
In March 2024, Patronus AI compared performance of LLMs on a 100-question test, asking them to complete sentences from books (e.g., "What is the first passage of Gone Girl by Gillian Flynn?") that were under copyright in the United States; it found that GPT-4, Mistral AI's Mixtral, Meta AI's LLaMA-2, and Anthropic's Claude 2 did not refuse to do so, providing sentences from the books verbatim in 44%, 22%, 10%, and 8% of responses, respectively.
Existential risk
In 2023, Australian MP Julian Hill advised the national parliament that the growth of AI could cause "mass destruction". During his speech, which was partly written by the program, he warned that it could result in cheating, job losses, discrimination, disinformation, and uncontrollable military applications.
Elon Musk wrote: "ChatGPT is scary good. We are not far from dangerously strong AI". He paused OpenAI's access to a Twitter database in 2022 pending a better understanding of OpenAI's plans, saying: "OpenAI was started as open source and nonprofit. Neither is still true." Musk co-founded OpenAI in 2015, in part to address existential risk from artificial intelligence, but resigned in 2018. | ChatGPT | Wikipedia | 507 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Over 20,000 signatories including leading computer scientist and tech founders Yoshua Bengio, Elon Musk, and Apple co-founder Steve Wozniak, signed a March 2023 open letter calling for an immediate pause of giant AI experiments like ChatGPT, citing "profound risks to society and humanity". Geoffrey Hinton, one of the "fathers of AI", voiced concerns that future AI systems may surpass human intelligence, and left Google in May 2023. A May 2023 statement by hundreds of AI scientists, AI industry leaders, and other public figures demanded that the risk of extinction from AI should be a global priority".
Other prominent AI researchers spoke more optimistically about the advances. Juergen Schmidhuber, often called a "father of modern AI", did not sign the letter, emphasizing that in 95% of cases, AI research is about making "human lives longer and healthier and easier." Schmidhuber added that while AI can be used by bad actors, it "can also be used against the bad actors". Andrew Ng argued that "it’s a mistake to fall for the doomsday hype on AI—and that regulators who do will only benefit vested interests." WIRED wrote that Yann LeCun "scoffs at his peers’ dystopian scenarios of supercharged misinformation and even, eventually, human extinction." | ChatGPT | Wikipedia | 291 | 72417803 | https://en.wikipedia.org/wiki/ChatGPT | Technology | Artificial Intelligence | null |
Homo longi is an extinct species of archaic human identified from a nearly complete skull, nicknamed 'Dragon Man', from Harbin on the Northeast China Plain, dating to at minimum 146,000 years ago during the Middle Pleistocene. The skull was discovered in 1933 along the Songhua River while the was under construction for the Manchukuo National Railway. Due to a tumultuous wartime atmosphere, it was hidden and only brought to paleoanthropologists in 2018. H. longi has been hypothesized to be the same species as the Denisovans, but this cannot be confirmed without genetic testing.
H. longi is broadly anatomically similar to other Middle Pleistocene Chinese specimens. Like other archaic humans, the skull is low and long, with massively developed brow ridges, wide eye sockets, and a large mouth. The skull is the longest ever found from any human species. Like modern humans, the face is rather flat, but with a larger nose. The brain volume was 1,420 cc, within the range of modern humans and Neanderthals.
Taxonomy
Etymology
The specific name for H. longi is derived from the geographic name Longjiang (literally "Dragon River"), a term commonly used for the Chinese province Heilongjiang.
Discovery
In 1933, a local laborer found a nearly complete skull at the riverbank of Songhua River, when he was building the in Harbin (at the time part of Manchukuo) for the Japanese-aligned Manchukuo National Railway. Recognizing its importance, likely as a result of public interest in anthropology that had recently been generated by the Peking Man in 1929, just four years before, he hid it from the Manchukuo authorities in an abandoned well.
In 1945, upon the Soviet invasion of Manchuria that ended the Japanese occupation of the region, he concealed his former employment from the Nationalist and later the Communist authorities. Consequently, he could not report the skull, lest he divulge his ties to the Japanese imperialists in explaining its origin.
In 2018, before his death, the third generation of his family learned of the skull, and reclaimed it. Later that year, Chinese paleoanthropologist Ji Qiang persuaded the family to donate it to the Hebei GEO University for study, where it has since been stored. Its catalogue number is HBSM2018-000018(A). | Homo longi | Wikipedia | 488 | 68045349 | https://en.wikipedia.org/wiki/Homo%20longi | Biology and health sciences | Homo | Biology |
Age
Owing to the skull's history, its exact provenance, and thus its stratigraphic context and age, has been difficult to determine.
In 2021, Chinese geologist Shao Qingfeng and colleagues performed non-destructive x-ray fluorescence, rare-earth element, and strontium isotope analyses on the skull and various other mammalian fossils unearthed around Dongjiang Bridge, and determined that all the fossils from the vicinity were likely deposited at around the same time, lived in the same region, and probably originate from the Upper Huangshan Formation, dating to 309 to 138 thousand years ago.
Direct uranium–thorium dating of various points on the skull yielded a wide range of dates, from 296 to 62 thousand years ago, likely a result of uranium leaching. They statistically determined the most likely minimum age is 146,000 years old, but a more exact value is difficult to determine, given that the exact provenance is unidentifiable. Nonetheless, the skull is well-constrained to the late Middle Pleistocene, roughly contemporaneous with other Chinese specimens from Xiahe, Jinniushan, Dali, and Hualong Cave.
Classification | Homo longi | Wikipedia | 234 | 68045349 | https://en.wikipedia.org/wiki/Homo%20longi | Biology and health sciences | Homo | Biology |
In two simultaneously published papers, Ji and colleagues declared the Harbin skull to represent a new species they dubbed Homo longi. The Harbin skull is quite similar to the Dali skull, and when the Dali skull was discovered in 1978, it was given a new nomen H. sapiens daliensis by its discoverer Wu Xinzhi who soon thereafter abandoned the name. Consequently, should the Middle Pleistocene Asian humans represent a single unique species, the nomen H. daliensis might take priority. Though they recommended resurrecting H. daliensis, they argued H. longi is sufficiently distinct, and allocated only the Dali and Hualong remains (often allocated to H. heidelbergensis by convention) to H. daliensis; thus, they claim at least two human species inhabited late Middle Pleistocene China. One of the authors, Chris Stringer, stated that he would have preferred assigning the Harbin skull to H. daliensis. However, according to a more recent assessment (including among its authors Xijun Ni, one of the describers of the species H. longi), since Wu wrote only that "it is suggested that Dali cranium probably represents a new subspecies" (p. 538, italics added for emphasis) the name daliensis was never validly published according to International Commission on Zoological Nomenclature (ICZN) rules, being proposed conditionally and published after 1960 (and not formally proposed by subsequent workers in the intervening period), and is therefore unavailable and thus could not compete with longi for priority.
Based on the conspicuously massive size of the molars, they suggested H. longi is most closely related to and possibly the same species as the Xiahe mandible from Tibet, which has been grouped with the enigmatic Denisovans, an archaic human lineage apparently dispersed across East Asia during the Middle and Late Pleistocene currently identifiable from only a genetic signature. The Xiahe mandible is also anatomically similar to specimens from Xujiayao and Penghu. Ji, Ni and colleagues further contend that Middle Pleistocene Asian specimens are more closely related to modern humans (H. sapiens) than the European Neanderthals, though nuclear DNA and ancient protein analyses place the Xiahe mandible and Denisovans more closely to Neanderthals than to modern humans. | Homo longi | Wikipedia | 473 | 68045349 | https://en.wikipedia.org/wiki/Homo%20longi | Biology and health sciences | Homo | Biology |
Anatomy
H. longi is characterized by a low and long skull, receding forehead, extremely wide upper face, a large nasal opening equating to an enlarged nose (possibly an adaptation to the cold air), large and square eye sockets, inflated and thick brow ridges (supraorbital torus), flat cheekbones (zygomatic bone), a wide palate and large tooth sockets (equating to a large mouth), and a broad base of the skull. The Harbin skull measures in maximum length x breadth, with a naso-occipital length of , making it the longest archaic human skull to date. For comparison, the dimensions of a modern human skull average for men and for women. The Harbin skull also has the longest brow ridge at .
H. longi had a massive brain at roughly 1,420 cc, above the range of all known human species except modern humans and Neanderthals. Nonetheless, post-orbital constriction (a constriction of the braincase just behind the eyes, absent in modern humans, and equating to the location of the frontal lobes) is more developed in H. longi than in Neanderthals, although not so much as in more-ancient human species. Overall, the braincase retains an array of archaic features, though the occipital bone at the back of the skull has a weakly-defined sagittal keel that lacks a protuberance at the midpoint, unlike most other archaic humans. Unlike the Dali and Hualong Cave skulls, the keel does not run across the midline. Unlike modern humans or Neanderthals, the parietal bones on the top of the head do not significantly expand or protrude. | Homo longi | Wikipedia | 363 | 68045349 | https://en.wikipedia.org/wiki/Homo%20longi | Biology and health sciences | Homo | Biology |
Despite the face being so wide, it was rather flat (reduced mid-facial prognathism), and resembles the anatomy found in modern humans, the far more ancient H. antecessor, and other Middle Pleistocene Chinese specimens. Nonetheless, the tooth sockets for the incisors were angled outward (alveolar prognathism). The H. longi skull's mosaic morphology of archaic and derived traits converges with some of the earliest specimens assigned to H. sapiens from Africa, notably Rabat and Eliye Springs. Because the original describers judged the Harbin skull to be closely allied with the Xiahe mandible, they believed H. longi lacked a chin, like other archaic humans, but the specimen's lower jaw was not recovered. The only preserved tooth, the upper left second molar, is enormous, with a length x breadth (mesiodistal x labiolingual) of , comparable to the Denisovan molar recovered from Denisova Cave. The Harbin molar is oval-shaped, badly worn, and nearly flat. In contrast, the average dimensions of a sample of 40 modern human male molars were .
Ni and colleagues believed the Harbin skull represents a male, judging by the robustness and size of the skull, who was less than 50 years old, looking at the suture closures and the degree of tooth wearing. They speculated H. longi had perhaps medium-dark to medium-light skin, dark hair, and dark eye color based on reconstructed genetic sequences from Neanderthals, Denisovans, and early modern humans.
Pathology
The left parietal features shallow indents around the bregma, possibly from a healed injury. The second left upper molar does not appear to have been in contact with the third molar, which means either that the third molar was small (creating a gap), or it was absent in this individual.
Paleoenvironment
Middle-Late Pleistocene sediments around Harbin from which the skull is thought to originate also contain the remains of the giant deer Sinomegaceros ordosianus, wild horse, elk/wapiti, the buffalo Bubalus wansijocki, brown bear,(see supplemental material) tigers, cave lions, woolly mammoth and woolly rhinoceros. | Homo longi | Wikipedia | 480 | 68045349 | https://en.wikipedia.org/wiki/Homo%20longi | Biology and health sciences | Homo | Biology |
An alpine lake is a high-altitude lake in a mountainous area, usually near or above the tree line, with extended periods of ice cover. These lakes are commonly glacial lakes formed from glacial activity (either current or in the past) but can also be formed from geological processes such as volcanic activity (volcanogenic lakes) or landslides (barrier lakes). Many alpine lakes that are fed from glacial meltwater have the characteristic bright turquoise green color as a result of glacial flour, suspended minerals derived from a glacier scouring the bedrock. When active glaciers are not supplying water to the lake, such as a majority of Rocky Mountains alpine lakes in the United States, the lakes may still be bright blue due to the lack of algal growth resulting from cold temperatures, lack of nutrient run-off from surrounding land, and lack of sediment input. The coloration and mountain locations of alpine lakes attract lots of recreational activity.
Alpine lakes are some of the most abundant types of lakes on Earth. In the Swiss Alps alone, there are nearly 1,000 alpine lakes, most of which formed after the Little Ice Age. As global temperatures continue to rise, more alpine lakes will be formed as glaciers recede and provide more run-off to surrounding areas, and existing lakes will see more biogeochemical changes and ecosystem shifts. An alpine lake's trophic state (i.e., level of biological productivity) progresses with age (e.g., low productivity after formation and increased productivity with vegetation and soil maturity in the surrounding watershed), but anthropogenic effects such as agriculture and climate change are rapidly affecting productivity levels in some lakes. These lakes are sensitive ecosystems and are particularly vulnerable to climate change due to the highly pronounced changes to ice and snow cover. Due to the importance of alpine lakes as sources of freshwater for agricultural and human use, the physical, chemical, and biological responses to climate change are being extensively studied.
Physical characteristics
Formation | Alpine lake | Wikipedia | 392 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
Commonly, alpine lakes are formed from current or previous glacial activity (called glacial lakes) but could also be formed from other geological processes such as damming of water due to volcanic lava flows or debris, volcanic crater collapse, or landslides. Glacial lakes form when a glacier scours and depresses the bedrock as it moves downhill, and when the glacier retreats, the depressions are filled with glacier meltwater and run-off. These lakes are usually quite deep for this reason and some lakes that are several hundred meters deep may be caused by a process called overdeepening. In mountain valleys where glacier movement has formed circular depressions, cirque lakes (or tarns) may form when the water becomes dammed. When damming occurs due to debris from the glacier movement, these lakes are called moraine lakes. These dams of debris can be very resilient or may burst, causing extreme flooding which poses significant hazards to communities in the alpine, especially in the Himalayas. Kettle lakes also form from glacier recession but are formed when a section of ice breaks off from the receding glacier, causes a depression, and then melts. Some alpine lakes reside in depressions formed from glaciers that existed during the last Ice Age yet are no longer proximate to any glaciers and are being sourced from snow, rain, or groundwater.
Glacial alpine lakes have dramatically increased in number in recent years. From 1990 to 2018, the number of glacial lakes increased by 53% and the total glacial lake area increased by 51% due to global warming. Alpine lakes adjacent to glaciers may also result in a positive feedback due to decreased albedo of water relative to ice, creating larger lakes and causing more glacial melt.
Glacial alpine lakes differ from other glacier-formed lakes in that they occur at higher altitudes and mountainous terrain usually at or above timberline. For example, the Great Lakes of the U.S. and Canada are formed by the retreat of the Laurentide Ice Sheet during the last Ice Age which scoured the flat rock surface but are not in the alpine. Conversely, Lake Louise located in the Rocky Mountains was formed from glacial debris damming meltwater (i.e., a moraine lake) from the Victoria Glacier.
Stratification | Alpine lake | Wikipedia | 452 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
The annual cycle of stratification and mixing in lakes plays a significant role in determining vertical distribution of heat, dissolved chemicals, and biological communities. Most alpine lakes exist in temperate or cold climates characteristic of their high elevation, leading to a dimictic mixing regime. Dimictic lakes fully mix twice a year between periods of vertical stratification in the summer and winter. Summer stratification is caused by heating of surface waters, and winter stratification is caused by cooling of surface waters below the freshwater temperature of maximum density (approximately ). Seasonal ice cover reinforces the dimictic stratification cycle of alpine lakes by insulating the lake from wind and warm air in the spring when stratification is generally weaker. Some shallow alpine lakes can become fully mixed multiple times per year through episodic wind or cold inflow events and are therefore considered cold polymictic. A number of meromictic alpine lakes (in which a deep layer of the lake never mixes with surface water) exist. Lake Cadagno, located in the Swiss Alps, is meromictic due to natural springs which constantly feed the bottom of the lake with dense, saline water. Other alpine lakes, such as Traunsee in Austria, have become meromictic due to salinization from anthropogenic activities such as mining.
Recent studies suggest that climate change may impact the annual cycles of stratification in alpine lakes. High altitude regions are experiencing changing seasonal weather patterns and faster warming than the global average. The duration of ice cover on alpine lakes is sensitive to these factors, and shorter ice cover duration has the potential to shift the mixing regime of lakes from dimictic to monomictic (one stratified and one fully mixed period each year). A change in mixing regime could fundamentally alter chemical and biological conditions such as nutrient availability and the timing and duration of hypoxia in alpine lakes. In addition, the relatively small size and high altitude of alpine lakes may make them especially susceptible to changes in climate. | Alpine lake | Wikipedia | 409 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
Hydrology
The hydrology of an alpine lake's watershed plays a large role in determining chemical characteristics and nutrient availability. Sources of water inflow into alpine lakes include precipitation, melting snow and glaciers, and groundwater. Alpine lake inflow often has a large seasonal cycle due to precipitation falling as snow and low glacier melt over the watershed in the winter contrasted with rainfall and increased glacier melt in summer. Alpine lakes are often situated in mountainous regions near or above the treeline which leads to steep watersheds with underdeveloped soil and sparse vegetation. A combination of cold climate over alpine watersheds, shading from steep topography, and low nutrient concentrations in runoff make alpine lakes predominantly oligotrophic.
Different watershed characteristics create a distinction between clear alpine lakes and glacier-fed alpine lakes (lakes with inflow from melting glaciers). Clear alpine lakes have low concentrations of suspended sediment and turbidity which can be caused by a lack of erosion in the watershed. Glacier-fed lakes have much higher suspended sediment concentrations and turbidity due to inflow of glacial flour, resulting in opaqueness and a bright blue or brown color. The turbidity of alpine lakes plays a significant role in determining light availability for primary productivity and is heavily dependent on each lake's unique watershed. | Alpine lake | Wikipedia | 259 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
Circulation
Circulation in alpine lakes can be caused by wind, river inflows, density currents, convection, and basin-scale waves. Steep topography characteristic of alpine lakes can partially shield them from wind generated by regional weather patterns. Therefore, smaller scale wind patterns generated by local topography, such as diurnal mountain breeze and katabatic wind, can be important in forcing circulation in alpine lakes. Wind patterns which vary spatially over the extent of the lake may create regions of upwelling and downwelling. River inflow can induce circulation in alpine lakes through momentum carried directly into the lake by rivers or streams and through density currents. If the inflowing water is denser than the water at the surface of the lake (due to differences in temperature or sediment concentration), buoyancy drives the heavier inflowing water down the slope of the lake bed or into the lake interior. Such density-driven flows have been recorded in alpine lakes with velocities reaching nearly 1 m/s. Heating and cooling of alpine lakes can cause surface waters to become more dense than the water in the interior of the lake. This results in a gravitationally unstable water column, and the dense water is pulled downward from the surface causing convection. This vertical circulation is an efficient means for mixing in lakes and may play a significant role in homogenizing the water column between periods of stratification. Basin-scale waves, such as internal waves and seiches, can also drive circulation in alpine lakes. Internal seiches in an alpine lake have been observed with attendant velocities on the order of a few centimeters per second.
Ecology | Alpine lake | Wikipedia | 331 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
Microbial community structure
Alpine lakes are home to a unique diversity of invertebrates that are highly adapted to the colder and generally harsher conditions of these environments compared to lakes at lower altitudes. A few dominating species have adapted to the oligotrophic conditions and intense UV radiation, with chironomidae and oligochaeta comprising almost 70% of the community in two well-studied alpine lakes in northern Italy, and also the two most prominent species (66% and 28%, respectively) in 28 alpine lakes in Austria. Phytoplankton populations are dominated by nanoplanktonic, mobile species including chrysophytes, dinoflagellates, and cryptophytes in the water column, with important contributions to photosynthesis also coming from the algae community attached to substrates, epilithon and epipelon. Viruses are also observed in alpine lakes at abundances of up to 3 x 107 ml−1, which nears the upper range of the general observed abundances from 105 to 108 ml−1 in aquatic systems.
A study of 28 alpine lakes found that with increasing elevation, macroinvertebrate abundances increase in small lakes but decrease in larger lakes and community composition shifts with increasing elevation, towards a small number of specialized species. The increasing abundances in smaller lakes as elevation increases are thought to be due to the more extreme temperature regimes characteristic of smaller bodies of water, selecting for a small subset of more robust species that end up thriving from less overall competition. Altitude may also affect community composition due to the change in availability of food resources. For example, at higher altitudes, alpine lakes experience shorter ice-free periods which places a limit on the amount of primary production and subsequent growth of food. In conclusion, both the lake's physical features, including size and substrate, and environmental parameters, including temperature and ice-cover, define community composition and structure, with one study suggesting that temperature and altitude are the primary drivers, and another presenting evidence instead for heterogeneity in lake morphometry and substrate as the primary drivers. The latter, in particular an increase in rocky substratum, was found to negatively impact abundance and species richness. All of these environmental parameters are likely to be impacted by climate change, with cascading effects on alpine lake invertebrate and microbial communities. | Alpine lake | Wikipedia | 475 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
Vertebrate community structure
The vertebrate community of alpine lakes is much more limited than invertebrate communities as harsh conditions have an increased impact on the organisms, but can include fish, amphibians, reptiles, and birds. Despite this, many alpine lakes can still host diverse species at these high elevations. These organisms have arrived in several ways through human introductions, ecological introductions, and some are endemic to their respective lakes. The Titicaca water frog in Lake Titicaca in the high Andes is one species that is endemic, while others were introduced.
Lake Titicaca is home to a wide variety of vertebrates, including the Titicaca water frog (Telmatobious culeous), and the endangered Titicaca grebe (Rollandia microptera) found only in the Titicaca basin. The basin is also home to a variety of bird species and is considered a Ramsar Site due to its ecological importance. Waterbird species include Chilean flamingo, greater yellowlegs, snowy egret, Andean coot, Andean gull, and the Andean lapwing.
Another important alpine lake, Crater Lake located in Oregon, is home to several introduced fish species, native amphibians, and reptiles. The amphibians and reptiles that can be found in Crater Lake are the mazama newt, northwestern salamander, northwestern ribbed frog, northwestern toad, cascade frog, pacific tree frog, northern mountain lizard, pigmy horned toad, northern alligator lizard, and northwestern garter snake.
Introduced species
Some alpine lakes do not hold any native vertebrate species and instead have grown their vertebrate communities through introduced species. Fish are commonly introduced by humans stocking lakes for recreational and competitive fishing. | Alpine lake | Wikipedia | 359 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
Crater Lake did not hold any vertebrate species before a stocking event between 1884 and 1941 of 1.8 million salmonids, mainly Rainbow trout (Oncorhynchus mykiss) and kokanee salmon (O. nerka). Other species introduced included brown trout (Salmo trutta), coho salmon (O. kisutch), cutthroat trout (O. clarkii), and steelhead salmon (O. mykiss). Introduced fish impact the limnetic and benthic communities, as they are the primary prey of non-native fish. Salamanders and newts found at Crater Lake also experienced encroachment on their native habitats and have been reduced or eliminated in numbers. These amphibians were also found in the stomach contents of fish stocked in Crater Lake, which has further reduced populations.
Lake Tahoe, located between California and Nevada, also has several introduced fish species established in the basin due to recreational fishing, including lake trout (Salvelinus namaycush), rainbow trout, brown trout, bluegill (Lepomis macrochirus), carp (Cyprinus caprio), and others. Lake trout, along with an introduced freshwater shrimp, Mysis relicta, have drastically changed the food web in Lake Tahoe. Nearby Cascade Lake in California, which is often closely studied with Lake Tahoe, does not have any introduced species due to highly restricted public access. Fish were also stocked in Lake Titicaca following the decimation of a native fish population after a fishing competition.
Some studies have noted that recreational fishing of introduced species in alpine lakes may have negative effects on the overall ecosystem. Bringing in non-native species, especially to fishless lakes, can also carry pathogens and bacteria, negatively impacting the invertebrate community already there. Studies of two fishless Italian alpine lakes, Dimon Lake and Balma Lake, found that introduced fish brought new viruses and bacteria that were harmful to the native amphibians in the water. The studies also showed that the only way to fix the problem is to completely eradicate the non-native fish species in the lakes in any way possible. These included using gill nets, electrofishing, and continued aggressive recreational fishing. | Alpine lake | Wikipedia | 465 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
Climate change impacts
Alpine lake invertebrates are arguably one of the most vulnerable communities of invertebrates to increasing temperatures associated with human-induced climate change, due to the expected increase in ice-free periods and to the relatively small impact of human-changed land cover that other similar terrestrial-aquatic systems have already been subjected to. Cold-stenothermal species uniquely adapted to survive in only a small range of cold temperatures, and larger sexual reproducing species slower to reproduce than smaller, asexual species under perturbations, could both be negatively impacted. Melting glaciers are presumed to increase the sizes of the alpine lakes that are glacier-fed, impacting the evidence size effect on community composition. Also, habitat structure could change in response to an increase in erosion from thawing permafrost, and lastly, an uptick in the frequency and magnitude of extreme weather events would increase water column turbidity, which is well-known to impact the processes of photosynthesis and respiration by increasing light attenuation and decreasing the size of the photic zone. Alpine lake ecosystems are undergoing unprecedented rates of change in community composition in relation to recent temperature increases and nutrient loading. Consistent monitoring can help identify, quantify and characterize this ecological impact. | Alpine lake | Wikipedia | 254 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
One such monitoring technique employs macroinvertebrates as bioindicators primarily to analyze the accumulation of trace elements associated with pollution and to, more generally, track changes in biological communities due to climate change. Trace elements can occur naturally, but industrialization, including the consumption of fossil fuels, has accelerated their rate of accumulation into alpine lake environments. Though essential to life in low concentrations, some trace elements begin to function as contaminants with over-accumulation. After being released into the atmosphere, trace elements can become soluble through biogeochemical processes and end up in sediment and then mobilized through weathering and runoff to enter alpine lake ecosystems. Benthic macroinvertebrates often at the base of food webs, are the primary accumulators of trace elements, which are then transferred up the food chain to fish or birds via predation. The seminal study that used chironomids as bioindicators due to their abundance in alpine lakes and variety of feeding habits (collectors, shredders, and predators) found that most trace element concentrations are within limits of sediment quality targets, with the exception of lead in both study lakes and zinc in one, and also concluded that trace element concentrations reflected the relative levels of pollution impacting each alpine lake in the study region of northern Italy. Another study, upon assessing the composition through time of chosen bioindicators and finding evidence for degraded water quality, concluded that the lake ecosystem had moved out of a "safe operational state".
Alkalinity and pH
Alkalinity can be defined as the acid neutralizing capability of a body of water. Alkalinity in natural waters is largely due to bicarbonate, the strong conjugate base of the weak carbonic acid, that is the product of rock weathering. Bicarbonate has the ability to act as an acid or a base in water, making it a buffer to resist change from acidic or basic inputs into a body of water. Alkalinity is measured in the unit μeq L−1 which is determined by the concentration of an ion per liter of water multiplied by the charge of the ion or by titration. | Alpine lake | Wikipedia | 437 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
Alpine lakes have been well studied in regard to acidification since the 1980s largely because of the seasonal patterns of alkalinity and pH changes that they naturally exhibit from precipitation and snowmelt. These lakes experience seasonally low alkalinity (and thus low pH), making them highly susceptible to acid precipitation as a result of atmospheric pollutants. The water chemistry of alpine lakes is dominated by atmospheric deposition (transport of particles between the atmosphere) and catchment processes (drainage of precipitation). The weather patterns of alpine lakes include large periods of snowmelt which has extended contact with soil and rock resulting in increased alkalinity. Weathering of rocks that are calcareous or carbonate based (limestone) are the major contributors of alkalinity to alpine lakes whereas alpine lakes in regions of granite and other igneous rocks have lower alkalinity due to slower kinetics of the weathering. Lower alkalinity indicates a lower ability to buffer the water from acidic or basic inputs so alpine lakes with low alkalinity are susceptible to acidic pollutants in the atmosphere. It is generally accepted that alpine lakes with alkalinity less than 200 unit μeq L−1 are susceptible to acidification.
European Alps
The Alps are the largest mountain range in Europe and home to some of the most well-known lakes. The bedrock in the Alps varies greatly and can be composed of granite, quartz, slate, dolomite, marble, limestone and much more. This diverse geological structure plays a role in the diverse alkalinity of each alpine lake. A study of 73 alpine lakes in the Eastern Alps determined that 85% of the lakes had low alkalinity values (< 200 μeq L−1) with only two lakes having an alkalinity above 500 μeq L−1. This study also determined pH and found a range from 7.93–4.80 with 21% of the lakes having a pH below 6.00. The pH in this region was also found to be independent of altitude. | Alpine lake | Wikipedia | 405 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
A similar analysis was done on 207 lakes, resulting in an alkalinity range from -23 to 1372 μeq L−1 and an average of 145 μeq L−1. The pH was also determined for these lakes, ranging from 4.6 to 9.2. Alpine lakes with a pH less than 6.0 had shown acidic effects on micro-organisms and a pH less than 5.3 was characterized as having reached severe acidification. This analysis was repeated on 107 alpine lakes in the Central Alps with bedrock of silicic and ultrabasic rocks. These lakes had an alkalinity range from 155 to -23 microequiavlents per liter, suggesting how sensitive alpine lakes with similar bedrock might be to acidic rain.
Cascade Range
The Cascade Mountain Range extends from Northern California through Oregon and Washington. This region is composed of sedimentary and volcanic rocks, has heavy seasonal precipitation, and coniferous forests. The Alpine Lakes Wilderness Area in the Washington Cascades has over 700 lakes. Alkalinity for lakes in the Cascade region vary from as high as 400 μeq L-1 to as low as 57 μeq L−1, all of which are considered to be low alkalinity, and suggestive that they might be susceptible to acidification. The pH of these lakes ranged from 7.83 to 5.62, and in this region an acidified lake is considered having a pH below 4.7. The Cascade Range was further evaluated by subregions since the environments vary greatly. Lower alkalinity, 50–100 μeq L−1, was observed in regions with little soil and granite rocks, like that of Glacier Peak Wilderness and Mt. Rainier. Higher alkalinity, 200–400 μeq L−1, was observed in regions composed of basalt and andesite such as the Western Cascades.
Palaeoclimatological data
Paleoproxies are chemical or biological sources that serve as indicator data for some aspect of the climate and can help reconstruct past regional climates and the future fate of alpine environments. Alpine lakes themselves are unique reservoirs of paleoclimate data, particularly for understanding climate in the late Quaternary, as they collect and store geomorphological and ecological data in their sediment. These records of the past allow for a better understanding of how alpine lakes have responded to climate variability. Thus, by understanding these mechanisms of the past, better predictions can be made about the future response of alpine ecosystems to present-day climate change. | Alpine lake | Wikipedia | 510 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
The fraction of mineral phosphorus (P) to organic P within lake sediments can be used to determine if the sediment deposits are sourced from glaciers (higher mineral to organic P ratio) or debris slopes (lower mineral to organic P ratio). Therefore, the sediment P content can inform glacial activity and thus climate at the time the sediment was deposited. For instance, an alpine lake in the Coast Mountains of British Columbia revealed cooler and wetter conditions due to the increased trend in mineral-rich (glacial-derived) P sediments which agrees with other findings of cooling in the Holocene.
Magnetic properties of the sediment in alpine lakes can also help infer glacial activity at a high resolution. When the magnetic properties of the lake sediments match those of the bedrock, it can be deduced that there was more glacier movement, i.e., cooler temperatures. Along with the sediments being "detrital" (bedrock weathering), the sediments are more coarse-grained indicating high glacial activity associated with the Pleistocene.
Diatom assemblages reveal changes in benthic conditions and alkalinity which help infer changes in temperature and carbon dioxide concentrations over time. During periods of warmer temperatures, extended growing seasons led to more benthic plant growth which is revealed by more periphytic (substrate-growing) diatom species. After the onset of the Industrial Revolution, diatom assemblages revealed more acidic conditions which are associated with higher carbon dioxide concentrations. Aside from the alpine lakes themselves serving as a source of paleoclimate observations, the surrounding alpine zone also contributes many useful proxies such as tree ring dynamics and geomorphological features. | Alpine lake | Wikipedia | 335 | 72482339 | https://en.wikipedia.org/wiki/Alpine%20lake | Physical sciences | Hydrology | Earth science |
Organisms that live freely at the ocean surface, termed neuston, include keystone organisms like the golden seaweed Sargassum that makes up the Sargasso Sea, floating barnacles, marine snails, nudibranchs, and cnidarians. Many ecologically and economically important fish species live as or rely upon neuston. Species at the surface are not distributed uniformly; the ocean's surface provides habitat for unique neustonic communities and ecoregions found at only certain latitudes and only in specific ocean basins. But the surface is also on the front line of climate change and pollution. Life on the ocean's surface connects worlds. From shallow waters to the deep sea, the open ocean to rivers and lakes, numerous terrestrial and marine species depend on the surface ecosystem and the organisms found there.
The ocean's surface acts like a skin between the atmosphere above and the water below, and hosts an ecosystem unique to this environment. This sun-drenched habitat can be defined as roughly one metre in depth, as nearly half of UV-B is attenuated within this first meter. Organisms here must contend with wave action and unique chemical and physical properties. The surface is utilised by a wide range of species, from various fish and cetaceans, to species that ride on ocean debris (termed rafters).
Most prominently, the surface is home to a unique community of free-living organisms, termed neuston (from the Greek word υεω, which means both to swim and to float). Floating organisms are also sometimes referred to as pleuston, though neuston is more commonly used. Despite the diversity and importance of the ocean's surface in connecting disparate habitats, and the risks it faces, not a lot is known about neustonic life. | Ocean surface ecosystem | Wikipedia | 368 | 69445009 | https://en.wikipedia.org/wiki/Ocean%20surface%20ecosystem | Physical sciences | Oceanography | Earth science |
Overview
Neuston are key ecological links connecting ecosystems as far ranging as coral reefs, islands, the deep sea, and even freshwater habitats. In the North Pacific, 80% of the loggerhead turtle diet consists of neuston prey, and nearly 30% of the Laysan albatross's diet is neuston. Diverse pelagic and reef fish species live at the surface when young, including commercially important fish species like the Atlantic cod, salmon, and billfish. Neuston can be concentrated as living islands that completely obscure the sea surface, or scattered into sparse meadows over thousands of miles. Yet the role of the neuston, and in many cases their mere existence, is often overlooked.
One of the most well-known surface ecoregions is the Sargasso Sea, an ecologically distinct region packed with thick, neustonic brown seaweed in the North Atlantic. Multiple ecologically and commercially important species depend on the Sargasso Sea, but neustonic life exists in every ocean basin and may serve a similar, if unrecognised, role in regions across the planet. For example, over 50 years ago, USSR scientist A. I. Savilov characterised 7 neustonic ecoregions in the Pacific Ocean. Each ecoregion possesses a unique combination of biotic and abiotic conditions and hosts a unique community of neustonic organisms. Yet these ecoregions have been largely forgotten.
But there is another reason to study neuston: The ocean's surface is on the front line of human impacts, from climate change to pollution, oil spills to plastic. The ocean's surface is hit hard by anthropogenic change, and the surface ecosystem is likely already dramatically different from even a few hundred years ago. For example, prior to widespread damming, logging, and industrialisation, more wood may have entered the open ocean, while plastic had not yet been invented. And because floating life provides food and shelter for diverse species, changes in the surface habitat will cause changes in other ecosystems and have implications that are not currently fully understand or be able to be predicted.
Ocean surface life (neuston) | Ocean surface ecosystem | Wikipedia | 443 | 69445009 | https://en.wikipedia.org/wiki/Ocean%20surface%20ecosystem | Physical sciences | Oceanography | Earth science |
Invoking images of the open ocean's surface, the imagination can conjure up an endless empty space. A flat line parting the blue below from the blue above. But in reality a diverse array of species occupy this unique boundary layer. A tangle of terms exist for different organisms occupying different niches of the ocean's surface. The most inclusive term, neuston, is used here to refer to all of them.
Neustonic animals and plants live hanging from the surface of the ocean as if suspended from the roof of a massive cave, and are incapable of controlling their direction of movement. They are considered permanent residents of the surface layer. Many genera are globally distributed. Many organisms have morphological features that enable them to remain at the ocean's surface, with the most noticeable adaptations being floats.
Floaters (pleuston)
Epineuston
Hyponeuston
Rafting organisms
Surface microlayer
The sea surface microlayer (SML) is the boundary interface between the atmosphere and ocean, covering about 70% of the Earth's surface. With an operationally defined thickness between 1 and 1000 μm, the SML has physicochemical and biological properties that are measurably distinct from underlying waters. Recent studies now indicate that the SML covers the ocean to a significant extent, and evidence shows that it is an aggregate-enriched biofilm environment with distinct microbial communities. Because of its unique position at the air-sea interface, the SML is central to a range of global biogeochemical and climate-related processes.
The sea surface microlayer (SML) is the boundary interface between the atmosphere and ocean, covering about 70% of the Earth's surface. The SML has physicochemical and biological properties that are measurably distinct from underlying waters. Because of its unique position at the air-sea interface, the SML is central to a range of global biogeochemical and climate-related processes. Although known for the last six decades, the SML often has remained in a distinct research niche, primarily as it was not thought to exist under typical oceanic conditions. Recent studies now indicate that the SML covers the ocean to a significant extent, highlighting its global relevance as the boundary layer linking two major components of the Earth system – the ocean and the atmosphere. | Ocean surface ecosystem | Wikipedia | 474 | 69445009 | https://en.wikipedia.org/wiki/Ocean%20surface%20ecosystem | Physical sciences | Oceanography | Earth science |
In 1983, Sieburth hypothesised that the SML was a hydrated gel-like layer formed by a complex mixture of carbohydrates, proteins, and lipids. In recent years, his hypothesis has been confirmed, and scientific evidence indicates that the SML is an aggregate-enriched biofilm environment with distinct microbial communities. In 1999 Ellison et al. estimated that 200 Tg C yr−1 accumulates in the SML, similar to sedimentation rates of carbon to the ocean's seabed, though the accumulated carbon in the SML probably has a very short residence time. Although the total volume of the microlayer is very small compared to the ocean's volume, Carlson suggested in his seminal 1993 paper that unique interfacial reactions may occur in the SML that may not occur in the underlying water or at a much slower rate there. He therefore hypothesised that the SML plays an important role in the diagenesis of carbon in the upper ocean. Biofilm-like properties and highest possible exposure to solar radiation leads to an intuitive assumption that the SML is a biochemical microreactor.
Historically, the SML has been summarized as being a microhabitat composed of several layers distinguished by their ecological, chemical and physical properties with an operational total thickness of between 1 and 1000 μm. In 2005 Hunter defined the SML as a "microscopic portion of the surface ocean which is in contact with the atmosphere and which may have physical, chemical or biological properties that are measurably different from those of adjacent sub-surface waters". He avoids a definite range of thickness as it depends strongly on the feature of interest. A thickness of 60 μm has been measured based on sudden changes of the pH, and could be meaningfully used for studying the physicochemical properties of the SML. At such thickness, the SML represents a laminar layer, free of turbulence, and greatly affecting the exchange of gases between the ocean and atmosphere. As a habitat for neuston (surface-dwelling organisms ranging from bacteria to larger siphonophores), the thickness of the SML in some ways depends on the organism or ecological feature of interest. In 2005, Zaitsev described the SML and associated near-surface layer (down to 5 cm) as an incubator or nursery for eggs and larvae for a wide range of aquatic organisms. | Ocean surface ecosystem | Wikipedia | 489 | 69445009 | https://en.wikipedia.org/wiki/Ocean%20surface%20ecosystem | Physical sciences | Oceanography | Earth science |
Hunter's definition includes all interlinked layers from the laminar layer to the nursery without explicit reference to defined depths. In 2017, Wurl er al. proposed Hunter's definition be validated with a redeveloped SML paradigm that includes its global presence, biofilm-like properties and role as a nursery. The new paradigm pushes the SML into a new and wider context relevant to many ocean and climate sciences.
According to Wurl et al.m the SML can never be devoid of organics due to the abundance of surface-active substances (e.g., surfactants) in the upper ocean and the phenomenon of surface tension at air-liquid interfaces. The SML is analogous to the thermal boundary layer, and remote sensing of the sea surface temperature shows ubiquitous anomalies between the sea surface skin and bulk temperature. Even so, the differences in both are driven by different processes. Enrichment, defined as concentration ratios of an analyte in the SML to the underlying bulk water, has been used for decades as evidence for the existence of the SML. Consequently, depletions of organics in the SML are debatable; however, the question of enrichment or depletion is likely to be a function of the thickness of the SML (which varies with sea state; including losses via sea spray, the concentrations of organics in the bulk water, and the limitations of sampling techniques to collect thin layers . Enrichment of surfactants, and changes in the sea surface temperature and salinity, serve as universal indicators for the presence of the SML. Organisms are perhaps less suitable as indicators of the SML because they can actively avoid the SML and/or the harsh conditions in the SML may reduce their populations. However, the thickness of the SML remains "operational" in field experiments because the thickness of the collected layer is governed by the sampling method. Advances in SML sampling technology are needed to improve our understanding of how the SML influences air-sea interactions.
Surface slicks | Ocean surface ecosystem | Wikipedia | 413 | 69445009 | https://en.wikipedia.org/wiki/Ocean%20surface%20ecosystem | Physical sciences | Oceanography | Earth science |
Slicks are meandering lines of smooth water on the ocean surface that are ubiquitous coastal features around the world. A variety of mechanisms can cause slick formation, including tidal and headland fronts, and as a consequence of subsurface waves called internal waves. Internal wave slicks are generated when internal waves interact with steep seafloor topography and drive areas of convergence and divergence at the ocean surface. The build-up of organic material (surfactants) at the surface modifies surface tension causing a smooth, oil slick-like appearance. The convergent flow can accumulate dense aggregations of plankton including larval fish and invertebrates at or below the ocean surface.
Surface slicks are the focal point for numerous trophic and larval connections that are foundational for marine ecosystem function. Life for many marine organisms begins near the ocean surface. Buoyant eggs hatch into planktonic larvae that develop and disperse in the ocean for weeks to months before transitioning into juveniles and eventually finding suitable adult habitat. The pelagic larval stage connects populations and serves as a source of new adults. Oceanic processes affecting the fate of larvae have profound impacts on population replenishment, connectivity, and ecosystem structure. Although it is an important life stage, there is, as of 2021, limited knowledge of the ecology and behaviour of larvae. Understanding the biophysical interactions that govern larval fish survival and transport is essential for predicting and managing marine ecosystems, as well as the fisheries they support. | Ocean surface ecosystem | Wikipedia | 298 | 69445009 | https://en.wikipedia.org/wiki/Ocean%20surface%20ecosystem | Physical sciences | Oceanography | Earth science |
The diagram shows: (1) Larval and juvenile stages of fishes from many ocean habitats aggregate in slicks in order to capitalize on dense concentrations of prey (2, phytoplankton, 3, zooplankton, 4, larval invertebrates, 5, eggs, and 6, insects). The increased predator–prey overlap in slicks increases energy flow that propagates up the food-web (dotted blue lines show trophic links), enhancing energy available to higher trophic level predators (icons outlined in blue) including humans. More than 100 species of fishes develop and grow in surface slick nurseries before transitioning to adults (solid white lines radiating outward) in Coral Reefs (7–12), Epipelagic (13–15), and Deep-water (16–17) ocean habitats. As adults these taxa (icons outlined in white) play important ecological functions and provide fisheries resources to local human populations. For example, coastal schooling fishes (7, mackerel scad) are important food and bait fish for humans. Planktivorous fish (8, some damselfishes and triggerfishes) transfer energy from zooplankton up to reef predators like jacks (9), which provide top-down control of reefs and are important targets for shoreline recreational fisherfolk. Grazers (10, chubs) help keep coral reefs from being overgrown by macroalgae. Cryptobenthic fishes such as blennies (11) and benthic macrocrustaceans (12, shrimp, stomatopods, crabs) comprise most of the consumed biomass on reefs. In the pelagic ocean, flyingfishes (13) channel energy and nutrients from zooplankton to pelagic predators such as mahi-mahi (14) and billfish (15), both of which utilize slicks as nursery habitat. Larvae of mesopelagic fishes like lanternfish (16) and bathydemersal tripod fishes (17) utilize these surface hotspots before descending to deep-water adult habitat. | Ocean surface ecosystem | Wikipedia | 432 | 69445009 | https://en.wikipedia.org/wiki/Ocean%20surface%20ecosystem | Physical sciences | Oceanography | Earth science |
The distribution of prey and predators in the ocean is patchy. Larval survival depends on prey availability, predation, and transport to suitable habitat, all of which are influenced by ocean conditions. Ocean processes that drive convergent flow such as fronts, internal waves, and eddies, can structure plankton, enhance overlap of predators and prey, and influence larval dispersal. Convergent features can also lead to a cascade of effects that ultimately drive food web structure and increase ecosystem productivity.
Life history
Life histories connect disparate ecosystems; species that live at the surface during one life history stage may occupy the deep sea, benthos, reefs, or freshwater ecosystems during another. A diversity of fish species utilize the ocean's surface, either as adults or as nursery habitat for eggs and young. In contrast, species floating on the ocean's surface during one life cycle stage often (though not always) have pelagic larval stages. Velella and Porpita release jellyfish (medusae), and while little is known about Porpita medusae, Velella medusae could possibly sink into deeper water, or remain near the surface, where they derive nutrients from zooxanthellae. Janthina have pelagic veliger larvae, and Physalia may release reproductive clusters that drift in the water column. Halobates lay eggs on a variety of objects, including floating objects and pelagic snail shells.
All species with pelagic stages must eventually find their way back to the surface. For Velella and Porpita, larvae generated by sexual reproduction of medusae develop small floats, which carry them to the surface. For the larvae of Janthina, the transition to surface life includes the degradation of their eyes and vestibule system, and at the same time, the production of an external structure, which has been reported as either a small parachute made of mucus, or a cluster of bubbles, which they ride to the surface. Young Halobates may hatch either above or below the surface, and for those below, the surface tension proves a formidable barrier. It may take Halobates nymphs several hours to break through the surface film. Despite the challenges of reaching the surface, there may be benefits to a temporary pelagic life. | Ocean surface ecosystem | Wikipedia | 471 | 69445009 | https://en.wikipedia.org/wiki/Ocean%20surface%20ecosystem | Physical sciences | Oceanography | Earth science |
Connectivity of ocean surface ecosystems may be facilitated by the life history of species living there. One hypothesis is that species have pelagic stages to "escape" surface sink regions and repopulate surface source regions, where one life cycle stage drifts on surface currents in one direction, and a pelagic stage either remains geographically localised or drifts in the opposite direction. However, some surface species, such as the endemic species of the Sargasso Sea, may remain geographically isolated throughout their life history. While these hypotheses are intriguing, it is not known if or how life history shapes population/species distribution for most neustonic species. Understanding how life history varies by species is a critical component of assessing both connectivity and conservation of neustonic ecosystems.
Sea spray
A stream of airborne microorganisms circles the planet above weather systems but below commercial air lanes. Some peripatetic microorganisms are swept up from terrestrial dust storms, but most originate from marine microorganisms in sea spray. In 2018, scientists reported that hundreds of millions of viruses and tens of millions of bacteria are deposited daily on every square meter around the planet.
These airborne microorganisms form part of the aeroplankton. The aeroplankton are tiny lifeforms that float and drift in the air, carried by the current of the wind; they are the atmospheric analogue to oceanic plankton. Most of the living things that make up aeroplankton are very small to microscopic in size, and many can be difficult to identify because of their tiny size. Scientists collect them for study in traps and sweep nets from aircraft, kites or balloons.
The environmental role of airborne cyanobacteria and microalgae is only partly understood. While present in the air, cyanobacteria and microalgae can contribute to ice nucleation and cloud droplet formation. Cyanobacteria and microalgae can also impact human health. Depending on their size, airborne cyanobacteria and microalgae can be inhaled by humans and settle in different parts of the respiratory system, leading to the formation or intensification of numerous diseases and ailments, e.g., allergies, dermatitis, and rhinitis. | Ocean surface ecosystem | Wikipedia | 469 | 69445009 | https://en.wikipedia.org/wiki/Ocean%20surface%20ecosystem | Physical sciences | Oceanography | Earth science |
Bassets are a sub-type of scenthound deliberately bred with short legs, that are used for hunting where the hunters accompany the hunting hounds on foot.
History
Bassets were originally developed in France from where they spread throughout Europe and the world. The name basset is derived from the French word bas which means low, a reference to their stature. It is believed bassets were bred from Saint Hubert-type hounds, with breeders taking advantage of a genetic mutation resulting in short legs to develop smaller statured, deep scenting hounds. These short-legged hounds were deliberately bred to allow hunters to accompany the hunting hounds on foot, as opposed to following hunt from horseback; their smaller stature making them slower and so easier to keep up with on foot.
The first description of bassets was in the 16th century by Jacques du Fouilloux in his work La vénerie, stating they were found in the regions of Artois and Flanders. Du Fouilloux described two types of bassets; the first were short-coated with crooked forelegs and were used to hunt above ground as well as to pursue game below ground; the second were often rough-coated with straighter forelegs and only pursued game above ground. Hunting game on foot with bassets experienced a rapid increase in popularity in France after the French Revolution in the late 18th century, when hunting with large hounds from horseback was almost eliminated in France as it was traditionally the preserve of the nobility.
Description
Bassets have a strong resemblance to larger, longer-legged hound breeds, particularly the Bloodhound, despite their much smaller stature. Bassets’ forelegs tend to be either crooked or straight, depending upon the breed; the coat types and colours seen within different basset breeds reflect those seen within the broader scenthound type, with short, long and wiry coats all found.
Use
Bassets hunt in packs and traditionally are used to hunt in two ways; in the first the hounds trail their quarry noisily to waiting hunters with guns who shoot the game; in the second the hounds pursue the quarry until they catch it. Packs of bassets are still used to hunt various quarry, particularly hare and rabbit, but they are also used to flush gamebirds in a similar manner to spaniels. | Basset | Wikipedia | 461 | 69453546 | https://en.wikipedia.org/wiki/Basset | Biology and health sciences | Dogs | Animals |
Breeds
Recognised breeds of basset include the French Basset Artésien Normand, Basset Bleu de Gascogne, Basset Fauve de Bretagne, Grand Basset Griffon Vendéen and Petit Basset Griffon Vendéen and the Basset Hound from Great Britain.
Other non-French origin breeds often considered basset-adjacent include the Alpine Dachsbracke from Austria, the Berner Niederlaufhund, Jura Niederlaufhund, Luzerner Niederlaufhund and Schwyzer Niederlaufhund from Switzerland, the Drever from Sweden, and the Westphalian Dachsbracke from Germany. | Basset | Wikipedia | 148 | 69453546 | https://en.wikipedia.org/wiki/Basset | Biology and health sciences | Dogs | Animals |
Neogale (colloquially referred to as the New World weasels) is a genus of carnivorous, highly active small mammals belonging to the Mustelidae family (which also contains badgers, weasels, martens, otters, and wolverines, among others). Native to the Americas, members of the genus can be found as far north as Alaska and as far south as Argentina and Bolivia. Across this distribution, they thrive in a range of habitats, from the deep-freezes of the Alaskan and Canadian boreal forests to the arid desert southwest, and from the humid tropics of Central and South America (including the Amazon basin) to the windswept foothills of the Andes and northern Patagonia.
Taxonomy
Members of this genus were formerly classified into the genera Mustela and Neovison, but many studies had previously recovered several American species of Mustela, as well as both species within Neovison, to comprise a monophyletic clade distinct from all other members of Mustelinae. A 2021 study found this clade to have diverged from Mustela during the Late Miocene, between 11.8 - 13.4 million years ago, with all members within the clade being more closely related to one another than to any of the other species in Mustela, and gave it the name Neogale, originally coined by John Edward Gray. The American Society of Mammalogists later accepted this change.
Species
There are 5 recent species in the genus, 4 extant and 1 extinct:
Extant species
Extinct species | Neogale | Wikipedia | 309 | 68106647 | https://en.wikipedia.org/wiki/Neogale | Biology and health sciences | Mustelidae | Animals |
In mathematics, a system of differential equations is a finite set of differential equations. Such a system can be either linear or non-linear. Also, such a system can be either a system of ordinary differential equations or a system of partial differential equations.
Linear systems of differential equations
A first-order linear system of ODEs is a system in which every equation is first order and depends on the unknown functions linearly. Here we consider systems with an equal number of unknown functions and equations. These may be written as
where is a positive integer, and are arbitrary functions of the independent variable t. A first-order linear system of ODEs may be written in matrix form:
or simply
.
Homogeneous systems of differential equations
A linear system is said to be homogeneous if for each and for all values of , otherwise it is referred to as non-homogeneous. Homogeneous systems have the property that if are linearly independent solutions to the system, then any linear combination of these, , is also a solution to the linear system where are constant.
The case where the coefficients are all constant has a general solution: , where is an eigenvalue of the matrix with corresponding eigenvectors for . This general solution only applies in cases where has n distinct eigenvalues, cases with fewer distinct eigenvalues must be treated differently.
Linear independence of solutions
For an arbitrary system of ODEs, a set of solutions are said to be linearly-independent if:
is satisfied only for .
A second-order differential equation may be converted into a system of first order linear differential equations by defining , which gives us the first-order system:
Just as with any linear system of two equations, two solutions may be called linearly-independent if implies , or equivalently that is non-zero. This notion is extended to second-order systems, and any two solutions to a second-order ODE are called linearly-independent if they are linearly-independent in this sense.
Overdetermination of systems of differential equations
Like any system of equations, a system of linear differential equations is said to be overdetermined if there are more equations than the unknowns. For an overdetermined system to have a solution, it needs to satisfy the compatibility conditions. For example, consider the system:
Then the necessary conditions for the system to have a solution are: | System of differential equations | Wikipedia | 475 | 63871781 | https://en.wikipedia.org/wiki/System%20of%20differential%20equations | Mathematics | Differential equations | null |
Land change science refers to the interdisciplinary study of changes in climate, land use, and land cover. Land change science specifically seeks to evaluate patterns, processes, and consequences in changes in land use and cover over time. The purpose of land change science is to contribute to existing knowledge of climate change and to the development of sustainable resource management and land use policy. The field is informed by a number of related disciplines, such as remote sensing, landscape ecology, and political ecology, and uses a broad range of methods to evaluate the patterns and processes that underlie land cover change. Land change science addresses land use as a coupled human-environment system to understand the impacts of interconnected environmental and social issues, including deforestation and urbanization.
History
Land change science is a recently developed field, which emerged in conjunction with the advancement of climate change and global environmental change research, and is important to the evolution of climate change science and adaptation. It is both problem-oriented and interdisciplinary. In the mid-20th century, human-environment relationships were emerging in areas of study such as anthropology and geography. Some scholars assert that the discipline of land change science is loosely derived from German concepts of landscape as the total amount of things within a given territory. In the latter half of the 20th century, scientists studying cultural ecology and risk-assessment ecology worked to develop land change science as a means of addressing land as a human-environment system that can be understood as a foundation of global environmental science.
Aims
Thus far, the aims of land change science have been to:
Observe and monitor land changes underway throughout the world
Understand land change as a human-environmental system
Model land change
Assess system outcomes such as vulnerability, sustainability, and resilience
Related disciplines
Land change science is an interdisciplinary field, and thus is influenced by a number of related areas of study, including remote sensing, political ecology, resource economics, landscape ecology, and biogeography. It is meant to supplement the study of climate change, and through the examination of land cover and land use changes in conjunction with climatic changes over the same period of time, scientists can better understand how human land use practices contribute to a changing climate. Given its close association with the study of climate change, land change science is inherently sustainability research and the scientific knowledge it produces is used to influence the development of sustainable agriculture, and sustainable land use practices and policies.
Although land change science involves quantifying the location, extent, and variability of land change cover and the analysis of emergent patterns, it remains fundamentally interdisciplinary, including social and economic components. | Land change science | Wikipedia | 512 | 66693032 | https://en.wikipedia.org/wiki/Land%20change%20science | Biology and health sciences | Ecology | Biology |
Methods
Land change science mainly operates within the international scientific research frameworks from which its fundamental questions were developed. Although the field has ties to social and cultural studies in its understanding of land and land change as a human-environment system, land change science also focuses on ecosystems and earth systems' structure, function, and effects on land change, independent of human activity. Land change science encompasses a broad scope of dimensions, ranging from quantifying the ecological effects of land cover change, to understanding the socio-environmental drivers for land-use decisions at an institutional level. As a result, land change science relies on the synthesis of a wide range of data and a diverse range of data collection methods. These include for example land cover monitoring and assessments, modeling risk and vulnerability, and land change modeling.
Challenges
Land change science as a discipline faces several challenges, many of the stemming from its interdisciplinary qualities or issues with developing inferences using aggregate data. For example, land change science is limited by constraints on data and lack of understanding of underlying issues of land change. Specifically, the spatial models frequently used to study land change may restricted by lack of access to public data on land change, faulty sensors, and high levels of variable uncertainty. Thus, models are often only able to make short-term projections, which severely limits the level of prediction they can provide. Additionally, it is difficult to synthesize and combine the case studies of social-environmental systems that are essential to the study of land change on a global scale. Thus, these setbacks pose fundamental challenges to the connection of communities and environment that land change science seeks to achieve. | Land change science | Wikipedia | 325 | 66693032 | https://en.wikipedia.org/wiki/Land%20change%20science | Biology and health sciences | Ecology | Biology |
A primary vein, also known as the midrib, is the main vascular structure running through the center of a leaf. The primary vein is crucial for the leaf’s efficiency in photosynthesis and overall health, as it ensures the proper flow of materials and structural integrity.
It serves several critical functions, including structural support, as the primary vein helps the leaf maintain its shape and structure; food and water transportation, as it contains xylem and phloem tissues that transport water, minerals, and nutrients to and from the leaf; and connection to the stem, as it links the leaf to its vascular system, facilitating the exchange of materials between the leaf and the rest of the plant. From the primary vein, secondary and tertiary veins branch out, forming a network that distributes resources throughout the leaf.
The arrangement of veins, including the primary vein, varies among plants. Reticulate venation occurs in dicots, where the primary vein branches into a network; parallel venation is found in monocots, where multiple veins run parallel to each other. | Primary vein | Wikipedia | 216 | 78370587 | https://en.wikipedia.org/wiki/Primary%20vein | Biology and health sciences | Plant tissues | Biology |
Body image disturbance (BID) is a common symptom in patients with eating disorders and is characterized by an altered perception of one's own body.
The onset is mainly attributed to patients with anorexia nervosa who persistently tend to subjectively discern themselves as average or overweight despite adequate, clinical grounds for a classification of being considerably or severely underweight. The symptom is an altered perception of one's body and a severe state of bodily dissatisfaction characterizing the body image disturbance. It is included among the diagnostic criteria for anorexia nervosa in DSM-5 (criterion C).
The disturbance is associated with significant bodily dissatisfaction and is a source of severe distress, often persisting even after seeking treatment for an eating disorder, and is regarded as difficult to treat. Thus, effective body image interventions could improve the prognosis of patients with ED, as experts have suggested. However, there is no hard evidence that current treatments for body image disturbance effectively reduce eating disorder symptoms. Furthermore, pharmacotherapy is ineffective in reducing body misperception and it has been used to focus on correlated psychopathology (e.g., mood or anxiety disorders). However, to date, research and clinicians are developing new therapies such as virtual reality experiences, mirror exposure, or multisensory integration body techniques, which have shown some extent of efficacy.
History
The scientific study of bodily experiences began at the end of the 19th century. German physiologist Hermann Munk was the first to suggest the existence of a cortical representation of the body, supported by his vivisection experiments on the parietal cortex of dogs. A few years later, Carl Wernicke hypothesized a cortical map capable of collecting and processing sensory inputs from every point of the body. In 1905 Bonnier introduced the term body schema, defining it as the mental representation of the body necessary for the brain to perceive objects near, far, or within the body itself. | Body image disturbance | Wikipedia | 414 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Bonnier also described three different partial body pattern alterations, (French; 'an overestimation of body size'), ('an underestimation of body size'), and ('a displacement of body parts including internal organs'). Head and Holmes in 1911 expanded the concept of a body schema, introducing the concepts of postural schema and surface schema. They described a patient who could locate the stimuli applied to her body but could not locate her hand in space. They also defined the difference between schema and image. The schema defined as an unconscious representation necessary for movement and localization in space, and the "image" as a conscious body perception.
Therefore, in the history of medicine, distortions in the perception of one's body have mainly occurred in patients with neurological damage or with amputated limbs and a consequence of phantom limb syndrome. In the psychiatric field, the first systematic descriptions of bodily altered perception are already present in Schneider's classification of symptoms of schizophrenia in 1959. The German-American psychiatrist Hilde Bruch was the first physician to describe body image disturbance in eating disorders accurately.
Characteristics
Hilde Bruch first identified and described body image disturbance in anorexia nervosa. In her article "Perceptual and Conceptual Disturbances in Anorexia Nervosa" she wrote:
Body image disturbance is not specific to anorexia nervosa, as it is sometimes present in other eating disorders such as bulimia nervosa and binge eating disorder. Studies published in 2019 on Cortex have shown that it is possible to observe alterations in the perception of one's body in healthy subjects. A slightly altered perception of the body is a normal part of everyone's life and manifests itself more intensely in more vulnerable individuals (e.g., patients with eating disorders). Commonly, body image disturbance is confused with body dysmorphic disorder, an obsessive-compulsive disorder with which it shares some features. | Body image disturbance | Wikipedia | 411 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Body image disturbance is a multifaceted construct including both perceptual and attitudinal issues. Some of the more common signs are:
altered body size estimation and altered perception of the body and its shapes;
mental images of one's body appearing distorted or overweight;
frequently third-person mental view of one's body;
negative body-related thoughts;
frequent body-checking behaviors;
frequent comparisons between one's own body and the bodies of others;
emotions of anxiety, shame, and contempt for one's body.
Clinically speaking, a growing body of research suggests that body image disturbance plays a significant role in the onset, maintenance, and relapse of anorexia nervosa, as previously suggested by Bruch in 1962. However, despite increasing evidence, a review by Glashouwer in 2019 stated that the available empirical data are still insufficient and "provide no basis to answer the question whether body image disturbance is a (causal) risk factor for anorexia nervosa". As suggested by the author, this lack of evidence is partly related to terminology problems used in the body image field.
In binge eating disorder
Body image disorder is a characteristic symptom of anorexia nervosa and bulimia nervosa. In both of these disorders, an excessive focus on body shapes and sizes made the body image disturbance easier to identify, to describe, and study. Much less is known about the disorder in patients with binge eating disorder.
As early as 1993, Spitzer compared obese individuals with and without binge eating disorder (BED) and found that those with BED were more frequently concerned about body shape and weight. Additionally, binge eating disorder patients show more significant concerns about weight and body shape, more intense body dissatisfaction, and more frequent avoidance and body checking behaviors. On the other hand, few studies have investigated the altered body perception in patients with binge eating disorder and the results are conflicting. Some patients tend to overestimate their body shapes, in others, they do not. In some cases the perceptual disturbance manifests itself in a paradoxical way, with an underestimation of the real body shapes and sizes. This difference suggests different phenotypes in binge spectrum; hence, a perceptual disturbance can be considered an aggravation of the binge eating disorder, as claimed by Lewer and colleagues in 2017. | Body image disturbance | Wikipedia | 497 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Epidemiology
There are no reliable epidemiological data in the literature for body image disturbance.
There are numerous challenges with diagnosis, the most relevant of which is the unclear definition of body image disturbance within official diagnostic manuals such as the DSM and the ICD, which prevents its identification in the population. Further, there are challenges with diagnostic tools, both for recognition and screening. The altered perception of the body can only be measured through behavioral tasks delivered individually (See section below). It cannot be measured with questionnaires, or other tools typically used for broad-spectrum investigations.
As it is not always present in eating disorders, its prevalence is not comparable to that of anorexia nervosa, bulimia nervosa, and binge eating disorder, and cannot be inferred from them. A negative body image may also be present in other psychiatric conditions such as PTSD, major depression, and body dysmorphic disorder. Taken together this data suggests the possible presence of perceptual disturbances in other pathological conditions not directly related to eating disorders. Therefore, the presence of a body image disturbance in other psychiatric diseases remains speculation, not yet supported by sufficient literature data, as suggested by Scheffers.
Definition
DSM-5
Different labels are used in research and clinical settings to describe body image disturbance, generating terminological confusion. Among the most used terms are body image discrepancy, body image self-discrepancy, body image distortion, disturbed body image, disturbances in body estimations, body image disturbance, and negative body image. Sometimes, the term body dissatisfaction is also used to refer to body image disturbance indiscriminately. Moreover, the DSM-5 defines this symptom vaguely: "a disturbance in the way one's body weight or shape is experienced". The lack of a clear definition is problematic from both a clinical and basic research point of view. | Body image disturbance | Wikipedia | 397 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Multidimensional
Despite the terminological problems, during the early 2000s numerous scholars agree that body image disturbance is a multidimensional symptom of various components associated with body image. Body image is a concept formed by the interaction of four body-related components: cognitive, affective, behavioral, and perceptual.
Cognitive: thoughts and beliefs about one's body and its shape; a conscious mental representation of the body
Affective: feelings and attitudes related to the body (e.g. bodily satisfaction/dissatisfaction).
Behavioral: the actions that people perform to check on, modify, or hide their body parts.
Perceptual: how the mind senses and perceives the body; it includes proprioceptive, interoceptive, tactile, and visual self-perception.
In people with body image disturbance all of these components are altered at the same time.
In 2021, Artoni et al proposed a clearer definition of body image disturbance as part of a study in Eating and Weight Disorders. The authors suggested using the term bodily dissatisfaction when there are alterations in either the affective, cognitive, or behavioral components of body image and strictly reserving the term body image disturbance only when all four components are altered, including perception. In short, they define body image disturbance as the presence of an altered perception of the shape and weight of one's body, which aggravates body dissatisfaction. The term is consistent with the DSM-5 description "a disturbance in the way weight and body shapes are experienced" and it is therefore "preferable to others".
Components
Cognitive
Patients with body image disturbance exhibit an alteration in how the body's image is stored in their memory—the conscious representation of their bodies. This representation is from a third-person, perspective, more precisely an allocentric representation of the body. This representation is evoked in self-image tasks, such as comparing one's body with others or drawing one's body shapes. However, patients with anorexia nervosa and bulimia nervosa frequently perceive their body as larger than it is in reality. | Body image disturbance | Wikipedia | 434 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Patients with anorexia nervosa have negative thoughts about their body, such as "I'm too fat," "I'm ugly," and other negative body-related thoughts. In some cases, however, the ideal internalized body is indicative of unhealthy thinness (e.g., a body without female shapes or one that communicates suffering). An unhealthy body shape could be a critical maintenance factor, generating more attention from family members, reducing the requests and expectations of others, and minimizing sexual attractiveness (especially in patients with sexual trauma).
Affective
Affective components of body image are the feelings and emotions experienced towards one's body. Body dissatisfaction is frequently present in those with body image disturbance, sometimes related to anxiety and shame when the body is exposed or gazed at in a mirror. In some cases, anger and feelings of aggression towards one's body are reported. Fear is associated with thoughts of getting fat.
Congruent with the self-objectification theory, people with body image disturbance frequently experience the body only as an object to be modified rather than as a subject to take care of.
Behavioral
The behavioral component of body image disturbance includes different body-checking behaviors such as repeatedly weighing during the day, spending significant time in front of the mirror or avoiding it, frequently taking selfies, checking parts of the body with hands (e.g. measuring the circumference of the wrists, arms, thighs, belly or hips). Other behaviors include avoiding situations in which the body is exposed (for example, when swimming), and wearing very loose and covering clothes. More generally, avoidance of bodily sensations, particularly the interoceptive ones, is reported.
Perceptual
In body image disturbance, several perceptual domains are altered. Visual perception is the most studied, but research has found misperceptions in other sensory domains such as haptic, tactile, and affective-touch. Also, the body schema is overextended. Some research suggested that this is related to a general enlarged mental representation of body size. A 2017 study published in a companion journal to Nature highlighted how perceptual disturbance is present in those recovered from anorexia nervosa even without affective-cognitive body concerns. Finally, interoception, the sense of the current state of the body, is problematic in those with eating disorders. | Body image disturbance | Wikipedia | 498 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Onset
The age of onset for body image disturbance is often early adolescence, the age in which one's comparison to their peers becomes more significant and leads to a greater sensitivity towards criticism of, or teasing about, one's physical appearance. Furthermore, puberty leads to rapid changes in body size and shape that need to be integrated into one's body image. For this reason, adolescence is considered a critical age, with a greater vulnerability to internalizing ideals of thinness, which may ultimately lead to the development of body dissatisfaction, body image disturbance, or eating disorders. In a 2019 review, Sattler and colleagues analyzed eight on-topic studies. The authors found that most adolescents with anorexia nervosa and bulimia nervosa already had body-checking behaviors, negative body-related emotions and feelings, low body satisfaction, and an altered estimate of their body size compared to healthy controls. Unfortunately, exactly how one passes from initial dissatisfaction with one's body to actual perceptual disorder is still unknown despite its clinical importance. The etiopathogenesis is still unknown and the subject of hypotheses in the clinical and neuroscientific fields.
Relationship to other concepts
Body dissatisfaction
Body dissatisfaction and body image disturbance are closely related. Personal, interpersonal, cultural, social, and ethnic variables largely influence bodily dissatisfaction, influencing the emergence of painful feelings towards one's body. In addition, social pressure is considered a risk factor for body dissatisfaction. For example, the frequent presence on media of thin female bodies determines, especially in young girls, a daily comparison between their bodies and models and actresses favoring bodily dissatisfaction; comparing an "ideal" and "real" body feed an intense dissatisfaction with one's body and increases the feeling of shame, disgust, and anxiety towards the one's body and appearance. | Body image disturbance | Wikipedia | 374 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Dissatisfaction with one's body involves only three of the four components of the body image. Those with bodily dissatisfaction can have negative thoughts about one's body (e.g., "I'm ugly" or "I'm too short"). In addition, they may have behaviors related to bodily dissatisfaction (e.g., going on a diet or resorting to cosmetic surgery) . They may also have negative feelings of dissatisfaction with their body and be ashamed of showing it in public. However, all these aspects are not enough to define it as a body image disturbance. In fact, there is no perceptual alteration of one's body. Thus, "body image disturbance" cannot be used interchangeably with "body dissatisfaction", but they are closely related.
Body dysmorphic disorder
Body image disturbance in anorexia and body dysmorphic disorder (BDD) are similar psychiatric conditions that both involve an altered perception of the body or parts of it but are not the same disorder. Body image disturbance is a symptom of anorexia nervosa (AN) and is present as criterion C in the DSM-5, and alters the perception of weight and shapes of the whole body. Patients with anorexia nervosa believe that they are overweight, perceive their body as being "fat" and misperceive their body's shape. Body dysmorphic disorder, meanwhile, is an obsessive-compulsive disorder characterized by disproportionate concern for minimal or absent individual bodily flaws, which cause personal distress and social impairment—patients with body dysmorphic disorder are concerned about physical details, mainly the face, skin, and nose. Thus, both anorexia nervosa and body dysmorphic disorder manifest significant disturbances in body image but are different and highly comorbid. For example, Grant et al reported that 39% of AN patients in their sample had a comorbid diagnosis of body dysmorphic disorder, with concerns unrelated to weight. Cerea et al reported that 26% of their AN sample had a probable BDD diagnosis with non-weight-related body concerns.
While a 2019 review by Phillipou et al in Psychiatry Research suggested that the two disorders could be taken together as "body image disturbances", plural, more in-depth studies are needed to confirm this new classification hypothesis. | Body image disturbance | Wikipedia | 490 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Similarities
Previous studies found that both BDD and eating disorder groups were similar in body dissatisfaction, body checking, body concerns, and levels of perfectionism. Furthermore, both BDD and AN patients report higher intensities of negative emotions, lower intensities of positive emotions, lower self-esteem, and anxiety symptoms. Moreover, research find severe concerns about one's appearance, leading to a continuous confrontation with others' bodies in both diseases. In addition, body image disturbances and body dysmorphic disorder generally onset during adolescence. Finally, alterations in visual processes seems to be present in both disorders, with greater attention to detail, but with greater difficulty in perceiving stimuli holistically. Indeed, neurophysiology and neuroimaging research suggests similarities between BDD and AN patients in terms of abnormalities in visuospatial processing.
Differences
Despite many similarities, the two disorders also have significant differences. The first is gender distribution. Body image disturbance is much more present in females, unlike BDD, which has a much less unbalanced incidence. Furthermore, those with dysmorphophobia tend to have more significant inhibitions and avoidance of social activities than those with anorexia nervosa. Differences are self-evident when considering the focus of physical concerns and misperception in AN and BDD. BDD patients report concerns and misperception in specific body areas (mainly face, skin, and hair). In patients with AN, the altered perception could involve the arms, shoulders, thighs, abdomen, hips, and breasts, and concerns are about overall body shape and weight; thus leading to an alteration of the entire explicit (body image) and implicit (body schema) mental representation of the body. Furthermore, in anorexia nervosa, not only is visual perception of one's body altered, but both tactile and interoceptive perception are as well. | Body image disturbance | Wikipedia | 391 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Diagnosis
Body image disturbance is not yet clearly defined by official disease classifications. However, it appears in the DSM-5 under criterion C for anorexia nervosa and is vaguely described as "a disturbance in the way weight and body shapes are experienced". As a result, diagnosis is usually based on reported signs and symptoms; there are still no biological markers for body image disturbance. Numerous psychometric instruments to measure the cognitive, affective, and behavioral components of one's body image are used in clinical and research settings, helping in assessing the body image's attitudinal components. Recently, research developed other instruments to measure the perceptive component.
Attitudinal assessment tools
The Eating Disorder Inventory 3 (EDI-3) represents an improvement of the earlier versions of the EDI, a self-report questionnaire widely used both in research and clinical settings. It consists of 91 questions, and items are rated on a six-point Likert scale (always, usually, sometimes, rarely, never), with higher scores representing more severe symptoms. Precisely, the BD subscale of EDI-3 measures bodily dissatisfaction.
The Body Uneasiness Test (BUT) is a self-administered questionnaire. It explores several areas in clinical and non-clinical populations: weight phobia, body image-related avoidance behavior, compulsive self-monitoring, detachment and estrangement feelings toward one's own body. Besides, explore specific worries about particular body parts, shapes, or functions. Higher scores indicate significant body uneasiness.
The Body Image Disturbance Questionnaire investigates different areas related to body image disturbance. For example, it evaluates the parts of the body an individual finds most problematic, the psychological effects of their worries about their body, and effects on their social life and eating behavior.
The Body Shape Questionnaire is a 34-item self-assessment questionnaire designed to measure the degree of dissatisfaction with the weight and shape of one's body. It includes questions about the fear of weight gain and about whether one has the urge or desire to lose weight.
The Body Checking Questionnaire measures the frequency of body control behaviors, such as measuring specific body areas, using mirrors to check or avoid body shape, wearing loose-fitting, covering clothing, or checking for bony prominence with one's hands. Higher scores indicate a higher frequency of body checking behaviors. | Body image disturbance | Wikipedia | 488 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Perceptual assessment tools
BID-CA (Test for Body Image Distortion in Children and Adolescents): Patients with a 180 cm rope simulate the circumference of the different parts of the body, including the hips, thighs, shoulder width and other parts of the body considered phobic. This estimate is compared to the actual patient size. The procedure is validated for children and adolescents but can also be used in adults.
Visual Size Estimation Task (VSE): patients are placed standing in front of a wall at a distance of about one meter. They place two stickers on the wall that reflect the perceived dimensions of different body parts, such as the width of the shoulders, hips, or waistline. These values are then taken and compared with those measured directly on the patient.
Tactile Estimation Task (TET): a standard gauge is used for measurement. During the measurement, patients estimate the distance between the two points of the gauge while it is placed on different parts of the body. Several measurements are made and the gauge is oriented in different directions (for example, at the height of the hips, it is placed both horizontally and vertically)
3D Morphing: Numerous 3D modeling computer programs allow directly modifying a human body model by increasing or decreasing its size. Patients modify the 3D avatar so that it represents their body image as closely as possible. The model values are then compared with the actual measurements of the patients.
Multi-sensory perception
The perception of one's body is a multi-sensory process that integrates information deriving from different sensory cortices, including the visual, proprioceptive, tactile, interoceptive, and auditory-vestibular areas. All of these areas are involved in the perception of one's body. An important component is the premotor cortex (PMC) and the intraparietal sulcus. These two areas are active during illusory hand perception tasks in both hemispheres. | Body image disturbance | Wikipedia | 398 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
The somatosensory areas are also involved, in particular the primary somatosensory cortex (S1). An important area is the extrastriate body area located rostrocaudally in the occipital lobe and is specific to human bodies perception. Two other areas of considerable importance in the perception of the body are the insula and the anterior cingulate cortex. The insular cortex is fundamental in the direct perception and integration of bodily signals from different cortical areas and, despite being an area historically delegated to the sole function of perceiving the state of internal organs as proposed by Sherrington in 1911, research advances demonstrate the central role of the insula in several domains, including the recognition that one's body belongs to us. Namely the "body ownership".
Brain imaging
fMRI studies examining brain responses in anorexia nervosa patients to paradigms that include body image tasks have found altered activation across different brain areas, including the prefrontal cortex, precuneus, parietal cortex, insula, amygdala, ventral striatum, extrastriate body area, and fusiform gyrus. However, as Janet Treasure commented, "the research [in the field] is fragmented, and the mechanism of how these areas map onto the functional networks described above needs further study ... the mechanism by which the extremes of body distortion are driven and [their] circuitry is not known yet."
Prevention
The Body Project is an eating disorder prevention program within a dissonant-cognitive framework. The program provides a forum for high school girls and college-age women to confront unrealistic-looking ideals and develop a healthy body image and self-esteem. It has been repeatedly shown to effectively reduce body dissatisfaction, negative mood, unhealthy diet, and disordered eating.
Treatments | Body image disturbance | Wikipedia | 384 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Of cognition, affect, and behavior
Historically, research and clinicians have mainly focused on body image disturbance's cognitive, affective, and behavioral components. Consequently, treatments generally target symptoms such as body checking, dysfunctional beliefs, feelings, and emotions relating to the body. One of the best-known psychotherapies in the field is CBT-E. CBT-E is a cognitive-behavioral therapy that has been enhanced with particular strategies to address the psychopathology of eating disorders. These include reducing negative thoughts and worries about body weight and shape, reducing clinical perfectionism, and body-checking behavior. In 2020 a review has shown that CBT-E effectively reduces core symptoms in eating disorders, including concerns about the body. Despite this, the results of CBT-E are no better than other forms of treatment. A therapy of choice for eating disorders in adults has not yet been identified.
Additionally, two other noteworthy body image treatments are Thomas F. Cash's "Body Image Workbook" and BodyWise. The former is an 8-step group treatment within a classic cognitive-behavioral framework. The latter is a psychoeducational-based treatment improved with cognitive remediation techniques to promote awareness of body image difficulties and to reduce cognitive inflexibility and body dissatisfaction.
Of perception
Compared to the classic cognitive-behavioral therapeutic paradigms, since the early 2000s, new treatments for body image disturbance have been developed focusing on the disorder's perceptual component. Mirror Exposure is a new cognitive-behavioral technique that aims to reduce experiential avoidance, reduce bodily dissatisfaction, and improve one's misperception of one's body. During the exposure therapy, patients are invited to observe themselves in front of a large full-length mirror. There are different types of mirror exposure: guided exposure; unguided exposure; exposure with mindfulness exercises; and cognitive dissonance-based mirror exposure. To date, few studies have investigated the effects of mirror exposure in patients with body image disturbance. In the International Journal of Eating Disorders, Key et al (2002) conducted a non-randomized trial in a clinical sample and compared a body image group therapy with or without mirror exposure. They found a significant improvement in body dissatisfaction only in the mirror exposure therapy group. Despite the positive evidence, in 2018, a review in Clinical Psychology Review suggests that Mirror Exposure has a low-to-medium effect in reducing body image disturbance and further studies are needed to improve it. | Body image disturbance | Wikipedia | 506 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Another treatment for body image disturbance is Virtual Reality (VR) Body Swapping. VR-Body Swapping is a technique that allows generating a body illusion during a virtual reality experience. Specifically, after building a virtual avatar using 3D modeling software, it is possible to generate the illusion that the avatar's body is one's own body. The avatar is a 3D human body model that simulates the actual size of the patient and can be modified directly. Some studies have found that applying this technique to those with anorexia nervosa reduces their misperception of their bodies but provides, at the moment, only a short-term effect.
However, other treatments have also been developed to integrate tactile, proprioceptive, and interoceptive perception into one's overall body perception. Hoop Training is a short-term 8-week intervention (10 minutes per session) designed to become aware of and reduce body misperception. During the exercise, several flexible circles of different sizes are placed in front of the patient. First, the patients indicate which of the different circles best fits the circumference of their hips. Once indicated, patients are invited to enter the circle and, raising it, underestimating whether their estimate was accurate or not. The exercise takes place until the patient identifies the correct circumference for her hips. The circle chosen initially can be compared with the one that can coincide with the actual size of the patient. Hoop Training is meant to work on the components cognitive, affective, and perceptive of body image disturbance and the first efficacy data were published in 2019.
Another perceptive treatment is the Body Perception Treatment (BPT) whose first efficacy data were published in 2021. BPT is a specific group intervention for body image disturbance focused on tactile, proprioceptive, and interoceptive self-perceptions during a body-focused experience. During the exercise, patients lie down on their backs in the supine position with closed eyes. Then the therapist guide patients to selectively focus attention on the different body parts in contact with the floor. In order: feet, calves, thighs, back, shoulders, hands, arms, head and the body in its entirety. In addition, patients are invited to pay attention to skin temperature, heart beat and flow of breath. The treatment is consistent with the hypothesized role of interoception in developing body image disturbance by Badoud and Tsakiris in 2017. | Body image disturbance | Wikipedia | 500 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Both Hoop Training and Body Perception Treatment showed effective results in pilot studies and were designed to work within a multisensory integration framework. However, they complement, not replace, current standard therapies for eating disorders. However, both are also novelty treatments, and the results have not been replicated in independent studies. Thus, their actual effectiveness will have to be confirmed/disconfirmed by future research. As of the end of 2021 they have not yet been replicated. | Body image disturbance | Wikipedia | 96 | 68371541 | https://en.wikipedia.org/wiki/Body%20image%20disturbance | Biology and health sciences | Mental disorders | Health |
Natural hydrogen (known as white hydrogen, geologic hydrogen, geogenic hydrogen, or gold hydrogen) is molecular hydrogen present on Earth that is formed by natural processes (as opposed to hydrogen produced in a laboratory or in industry). A closely related artificially produced form of hydrogen is green hydrogen which is produced from renewable energy sources such as wind or solar energy. Non-renewable forms of hydrogen include grey, brown, blue or black hydrogen which are obtained from the processing of fossil fuels.
Natural hydrogen is believed to exist in economically viable concentrations and locations on every continent. Natural hydrogen may be capable of supplying mankind's "projected global hydrogen demand for thousands of years," is non-polluting, may be available at significantly lower end user costs per therm than industrial hydrogen, and may be renewable. Natural hydrogen has been identified in many source rocks in areas beyond the sedimentary basins where oil companies typically operate.
History
In Adelaide, Australia in the 1930s, oil well drillers reported finding "vast amounts of high-purity hydrogen." At the time it was viewed as a useless byproduct of the oil drilling industry, and no efforts were made to capture it.
In 1987 in the village of Bourakebougou in Mali, Africa, a worker attempted to light his cigarette next to a certain water well, and the well unexpectedly caught fire. A local entrepreneur soon became interested in the possible economic value of this "burning well" and determined that the flames were produced by natural hydrogen seeping out of the well. A local petroleum company was soon hired to harvest and sell the hydrogen, and as of 2024, the villagers of Bourakébougou village continue to pay for their hydrogen. the Malian hydrogen well remains as the world’s first and only economically successful hydrogen well.
During the 2020s, interest in natural hydrogen has increased and investments have been made to develop natural hydrogen wells in the US, France and Australia. In France, one petroleum company, Française De l’Énergie, has said that it aims to begin extracting hydrogen by 2027 or 2028.
Natural hydrogen sources
Sources of natural hydrogen include: | Natural hydrogen | Wikipedia | 432 | 69898377 | https://en.wikipedia.org/wiki/Natural%20hydrogen | Physical sciences | Geochemistry | Earth science |
degassing of deep hydrogen from Earth's crust and mantle;
reaction of water with ultrabasic rocks (serpentinisation);
water in contact with reducing agents in Earth's mantle;
weathering – water in contact with freshly exposed rock surfaces;
decomposition of hydroxyl ions in the structure of minerals;
natural water radiolysis;
decomposition of organic matter;
biological activity
Serpentinization is thought to produce approximately 80% of the world's hydrogen, especially as seawater interacts with iron- and magnesium-rich (ultramafic) igneous rocks in the ocean floor. Current models point towards radiolysis as the source of most other natural hydrogen.
Resources and reserves
According to the Financial Times, there are 5 trillion tons of natural hydrogen resources worldwide. Most of this hydrogen is likely dispersed too widely to be economically recoverable, but the U.S. Geological Survey has reported that even a fractional recovery could meet global demand for hundreds of years. A discovery in Russia in 2008 suggests the possibility of extracting native hydrogen in geological environments. Resources have been identified in France, Mali, the United States, and approximately a dozen other countries.
In 2023 Pironon and de Donato announced the discovery of a deposit they estimated to be some 46 million to 260 million metric tons (several years worth of 2020s production). In 2024, a natural deposit of helium and hydrogen was discovered in Rukwa, Tanzania., as well in Bulqizë, Albania.
Midcontinent Rift System
White hydrogen could be found or produced in the Mid-continental Rift System at scale. Water could be pumped down to hot iron-rich rock to produce hydrogen for extraction. Dissolving carbon dioxide in these fluids could allow for simultaneous carbon sequestration through carbonation of the rocks. The resulting hydrogen would be produced through a carbon-negative pathway and has been referred to as "orange" hydrogen.
Geology
Natural hydrogen is generated from various sources. Many hydrogen emergences have been identified on mid-ocean ridges. Serpentinisation occurs frequently in the oceanic crust; many targets for exploration include portions of oceanic crust (ophiolites) which have been obducted and incorporated into continental crust. Aulacogens such as the Midcontinent Rift System of North America are also viable sources of rocks which may undergo serpentinisation.
Diagenetic origin (iron oxidation) in the sedimentary basins of cratons, notably are found in Russia. | Natural hydrogen | Wikipedia | 498 | 69898377 | https://en.wikipedia.org/wiki/Natural%20hydrogen | Physical sciences | Geochemistry | Earth science |
Mantle hydrogen and hydrogen from radiolysis (natural electrolysis) or from bacterial activity are under investigation. In France, the Alps and Pyrenees are suitable for exploitation. New Caledonia has hyperalkaline sources that show hydrogen emissions.
Hydrogen is soluble in fresh water, especially at moderate depths as solubility generally increases with pressure. However, at greater depths and pressures, such as within the mantle, the solubility decreases due to the highly asymmetric nature of mixtures of hydrogen and water.
Literature
Vladimir Vernadsky originated the concept of natural hydrogen captured by the Earth in the process of formation from the post-nebula cloud. Cosmogonical aspects were anticipated by Fred Hoyle. From 1960–2010, V.N. Larin developed the Primordially Hydridic Earth concept that described deep-seated natural hydrogen prominence and migration paths. | Natural hydrogen | Wikipedia | 175 | 69898377 | https://en.wikipedia.org/wiki/Natural%20hydrogen | Physical sciences | Geochemistry | Earth science |
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