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HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Axiomatic Theory of Receptive Fields
Receptive field profiles registered by cell recordings have shown that mammalian vision has developed receptive fields tuned to different sizes and orientations in the image domain as well as to different image velocities in space-time. Corresponding cell recordings in the auditory system has shown that mammals have developed receptive fields tuned to different frequencies as well as temporal transients. This article describes normative theories that have been developed to explain these properties of sensory receptive fields based on structural properties of the environment. Beyond theoretical explanation of biological phenomena, these theories can also be used for computational modelling of biological receptive fields and for building algorithms for artificial perception based on sensory data.
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  • 07 Nov 2022
Topic Review
RNA World Hypothesis
The RNA world hypothesis proposes that RNA was the first life-form on earth, later developing a cell membrane around it and becoming the first prokaryotic cell.
  • 2.1K
  • 07 Nov 2022
Topic Review
Operational View
Operational View (OV) is one of the basic views defined in the enterprise architecture (EA) of the Department of Defense Architecture Framework V1.5 (DoDAF) and is related with concept of operations. Under DODAF 2, which became operational in 2009, the collections of views are now termed 'viewpoints' and no longer views. Other enterprise architecture frameworks may or do have operational views. For example, the MODAF has an Operational Viewpoint and the NATO Architecture Framework has an Operational View (collection of subviews). This article will further explain the construction of the Operational View of the DoDAF V1.5.
  • 1.8K
  • 07 Nov 2022
Topic Review
Linguistics in Science Fiction
Linguistics has an intrinsic connection to Science Fiction stories given the nature of science fiction. As mentioned in Aliens and Linguists: Language Study and Science Fiction by Walter E. Meyers, science fiction is almost always concerned with the idea of communication, such as communication with aliens and machines, or communication using dead languages and evolved languages of the future. Authors of science fiction at times use Linguistics and Linguistic theories as a tool for storytelling, although technical terms are rarely used with authors only going into as much detail as the reader will understand. While Linguistics can be found to be employed by writers of science fiction, it must be noted that not all uses are accurate to actual Linguistics and Linguistic Theories. Nevertheless, there still exists the lingering presence and use of Linguistics (even if inaccurate) in such cases. As mentioned by Walter E. Meyers, the ability to make a story seem more unfamiliar and exotic, and an alien seem less of a costumed human who merely differs in physical appearance, is only possible through the use of language. It is this ability that appears to draw the boundary between great works of science fiction and those lesser so. As such, Linguistics, the scientific study of language, comes to hold an important role in the genre of science fiction.
  • 2.2K
  • 10 Nov 2022
Topic Review
Self-Mixing Laser Interferometry
Self-mixing or back-injection laser interferometry is an interferometric technique in which a part of the light reflected by a vibrating target is reflected into the laser cavity, causing a modulation both in amplitude and in frequency of the emitted optical beam. In this way, the laser becomes sensitive to the distance traveled by the reflected beam thus becoming a distance, speed or vibration sensor. The advantage compared to a traditional measurement system is a lower cost thanks to the absence of collimation optics and external photodiodes.
  • 1.5K
  • 09 Nov 2022
Topic Review
IBM Integration Bus
IBM APP Connect Enterprise (abbreviated as IBM ACE, formerly known as IBM Integration Bus or WebSphere Message Broker) is IBM's integration broker from the WebSphere product family that allows business information to flow between disparate applications across multiple hardware and software platforms. Rules can be applied to the data flowing through the message broker to route and transform the information. The product is an Enterprise Service Bus supplying a communication channel between applications and services in a service-oriented architecture. IBM ACE provides capabilities to build solutions needed to support diverse integration requirements through a set of connectors to a range of data sources, including packaged applications, files, mobile devices, messaging systems, and databases. A benefit of using IBM ACE is that the tool enables existing applications for Web Services without costly legacy application rewrites. ACE avoids the point-to-point strain on development resources by connecting any application or service over multiple protocols, including SOAP, HTTP and JMS. Modern secure authentication mechanisms, including the ability to perform actions on behalf of masquerading or delegate users, through MQ, HTTP and SOAP nodes are supported such as LDAP, X-AUTH, O-AUTH, and two-way SSL. A major focus of IBM ACE in its latest release is the capability of the product's runtime to be fully hosted in a cloud. Hosting the runtime in the cloud provides certain advantages and potential cost savings compared to hosting the runtime on premises as it simplifies the maintenance and application of OS-level patches which can sometimes be disruptive to business continuity. Also, cloud hosting of IBM ACE runtime allows easy expansion of capacity by adding more horsepower to the CPU configuration of a cloud environment or by adding additional nodes in an Active-Active configuration. Another advantage of maintaining ACE runtimes in the cloud is the ability to configure access to your ACE functionality separate and apart from your internal network using DataPower or API Connect devices. This allows people or services on the public internet to access your Enterprise Service Bus without passing through your internal network, which can be a more secure configuration than if your ESB was deployed to your internal on premises network. IBM ACE embeds a Common Language Runtime to invoke any .NET logic as part of an integration. It also includes full support for the Visual Studio development environment, including the integrated debugger and code templates. IBM Integration Bus includes a comprehensive set of patterns and samples that demonstrate bi-directional connectivity with both Microsoft Dynamics CRM and MSMQ. Several improvements have been made to this current release, among them the ability to configure runtime parameters using a property file that is part of the deployed artifacts contained in the BAR ('broker archive') file. Previously, the only way to configure runtime parameters was to run an MQSI command on the command line. This new way of configuration is referred to as a policy document and can be created with the new Policy Editor. Policy documents can be stored in a source code control system and a different policy can exist for different environments (DEV, INT, QA, PROD). IBM ACE is compatible with several virtualization platforms right out-of-the-box, Docker being a prime example. With ACE, you can download from the global Docker repository a runtime of IBM ACE and run it locally. Because ACE has its administrative console built right into the runtime, once the Docker image is active on your local, you can do all the configuration and administration commands needed to fully activate any message flow or deploy any BAR file. In fact, you can construct message flows that are microservices and package these microservices into a Docker deployable object directly. Because message flows and BAR files can contain Policy files, this node configuration can be automatic and no or little human intervention is needed to complete the application deployment.
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  • 07 Nov 2022
Topic Review
Milas
Milas (Ancient Greek:, Mylasa) is an ancient city and the seat of the district of the same name in Muğla Province in southwestern Turkey. The city commands a region with an active economy and very rich in history and ancient remains, the territory of Milas containing a remarkable twenty-seven archaeological sites of note. The city was the first capital of ancient Caria and of the Anatolian beylik of Menteşe in mediaeval times. The nearby Mausoleum of Hecatomnus is classified as a UNESCO World Heritage Site. Milas is focused on agricultural and aquacultural processing, related industrial activities, services, transportation (particularly since the opening of Milas-Bodrum Airport), tourism and culture. The centre lies about 20 km from the coast and is closer to the airport than Bodrum itself, with many late arrival passengers of the high season increasingly opting to stay in Milas rather than in Bodrum where accommodation is likely to be difficult to find. Milas district covers a total area of 2167 km2 and this area follows a total coastline length of 150 km, both to the north-west in the Gulf of Güllük and to the south along the Gulf of Gökova, and to these should be added the shores of Lake Bafa in the north divided between the district area of Milas and that of Aydın district of Söke. Along with the province seat of Muğla and the province's southernmost district of Fethiye, Milas is among the prominent settlements of south-west Turkey, these three centers being on a par with each other in terms of all-year population and the area their depending districts cover. Five townships have their own municipalities, and a total of 114 villages depend on Milas, distinguishing the district with a record number of dependent settlements for a very wide surrounding region. Milas center is situated on a fertile plain at the foot of Mount Sodra, on and around which sizable quarries of white marble are found and have been used since very ancient times.
  • 1.8K
  • 07 Nov 2022
Topic Review
Hybrid Fibre-Coaxial
Hybrid fiber-coaxial (HFC) is a telecommunications industry term for a broadband network that combines optical fiber and coaxial cable. It has been commonly employed globally by cable television operators since the early 1990s. In a hybrid fiber-coaxial cable system, the television channels are sent from the cable system's distribution facility, the headend, to local communities through optical fiber subscriber lines. At the local community, a box called an optical node translates the signal from a light beam to radio frequency (RF), and sends it over coaxial cable lines for distribution to subscriber residences. The fiberoptic trunk lines provide adequate bandwidth[weasel words] to allow future expansion and new bandwidth-intensive services.
  • 1.9K
  • 07 Nov 2022
Topic Review
Mesenteric Ischemia
Mesenteric ischemia is a medical condition in which injury to the small intestine occurs due to not enough blood supply. It can come on suddenly, known as acute mesenteric ischemia, or gradually, known as chronic mesenteric ischemia. The acute form of the disease often presents with sudden severe abdominal pain and is associated with a high risk of death. The chronic form typically presents more gradually with abdominal pain after eating, unintentional weight loss, vomiting, and fear of eating. Risk factors for acute mesenteric ischemia include atrial fibrillation, heart failure, chronic kidney failure, being prone to forming blood clots, and previous myocardial infarction. There are four mechanisms by which poor blood flow occurs: a blood clot from elsewhere getting lodged in an artery, a new blood clot forming in an artery, a blood clot forming in the superior mesenteric vein, and insufficient blood flow due to low blood pressure or spasms of arteries. Chronic disease is a risk factor for acute disease. The best method of diagnosis is angiography, with computed tomography (CT) being used when that is not available. Treatment of acute ischemia may include stenting or medications to break down the clot provided at the site of obstruction by interventional radiology. Open surgery may also be used to remove or bypass the obstruction and may be required to remove any intestines that may have died. If not rapidly treated outcomes are often poor. Among those affected even with treatment the risk of death is 70% to 90%. In those with chronic disease bypass surgery is the treatment of choice. Those who have thrombosis of the vein may be treated with anticoagulation such as heparin and warfarin, with surgery used if they do not improve. Acute mesenteric ischemia affects about five per hundred thousand people per year in the developed world. Chronic mesenteric ischemia affects about one per hundred thousand people. Most people affected are over 60 years old. Rates are about equal in males and females of the same age. Mesenteric ischemia was first described in 1895.
  • 530
  • 07 Nov 2022
Topic Review
Tuskegee Syphilis Experiment
The Tuskegee Study of Untreated Syphilis in the African American Male was a clinical study conducted between 1932 and 1972 by the United States Public Health Service. The purpose of this study was to observe the natural history of untreated syphilis; the African-American men in the study were only told they were receiving free health care from the Federal government of the United States. The Public Health Service started the study in 1932 in collaboration with Tuskegee University (then the Tuskegee Institute), a historically black college in Alabama. Investigators enrolled in the study a total of 600 impoverished, African-American sharecroppers from Macon County, Alabama. Of these men, 399 had latent syphilis, with a control group of 201 men who were not infected. As an incentive for participation in the study, the men were promised free medical care, but were deceived by the PHS, who disguised placebos, ineffective methods, and diagnostic procedures as treatment. The men who had syphilis were never informed of their diagnosis, despite the risk of infecting others, and the fact that the disease could lead to blindness, deafness, mental illness, heart disease, bone deterioration, collapse of the central nervous system, and death.. According to the Centers for Disease Control and Prevention, the men were told that they were being treated for "bad blood,” a colloquialism that described various conditions such as syphilis, anemia and fatigue. "Bad blood"—specifically the collection of illnesses the term included—was a leading cause of death within the southern African-American community. The men were initially told that the study was only going to last six months, but it was extended to 40 years. After funding for treatment was lost, the study was continued without informing the men that they would never be treated. None of the infected men were treated with penicillin despite the fact that by 1947, the antibiotic had become the standard treatment for syphilis. Study clinicians could have chosen to treat all syphilitic subjects and close the study, or split off a control group for testing with penicillin. Instead, they continued the study without treating any participants; they withheld treatment and information about it from the subjects. In addition, scientists prevented participants from accessing syphilis treatment programs available to other residents in the area. The study continued, under numerous Public Health Service supervisors, until 1972, when a leak to the press resulted in its termination on November 16 of that year. The victims of the study, all African-American, included numerous men who died of syphilis, 40 wives who contracted the disease and 19 children born with congenital syphilis. The 40-year Tuskegee Study of Untreated Syphilis in the African American Male study was a major violation of ethical standards. Researchers knowingly failed to treat participants appropriately after penicillin was proven to be an effective treatment for syphilis and became widely available. Moreover, participants remained ignorant of the study clinicians’ true purpose, which was to observe the natural course of untreated syphilis. The revelation in 1972 of study failures by a whistleblower, Peter Buxtun, led to major changes in U.S. law and regulation concerning the protection of participants in clinical studies. Now studies require informed consent, communication of diagnosis and accurate reporting of test results. The Tuskegee Syphilis Study, cited as "arguably the most infamous biomedical research study in U.S. history," led to the 1979 Belmont Report and to the establishment of the Office for Human Research Protections (OHRP). It also led to federal laws and regulations requiring institutional review boards for the protection of human subjects in studies involving them. The OHRP manages this responsibility within the United States Department of Health and Human Services (HHS). On May 16, 1997, President Bill Clinton formally apologized on behalf of the United States to victims of the study.
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  • 07 Nov 2022
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