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Topic Review

Cholera Outbreaks and Pandemics

Seven cholera pandemics have occurred in the past 200 years, with the first pandemic originating in India in 1817. Additionally, there have been many documented cholera outbreaks, such as a 1991–1994 outbreak in South America and, more recently, the 2016–2021 Yemen cholera outbreak. Although much is known about the mechanisms behind the spread of cholera, this has not led to a full understanding of what makes cholera outbreaks happen in some places and not others. Lack of treatment of human feces and lack of treatment of drinking water greatly facilitate its spread. Bodies of water have been found to serve as a reservoir, and seafood shipped long distances can spread the disease. Between 1816 and 1923, the first six cholera pandemics occurred consecutively and continuously over time. Increased commerce, migration, and pilgrimage are credited for its transmission. Late in this period (particularly 1879–1883), major scientific breakthroughs toward the treatment of cholera develop: the first immunization by Pasteur, the development of the first cholera vaccine, and identification of the bacterium Vibrio cholerae by Filippo Pacini and Robert Koch. After a long hiatus, a seventh cholera pandemic spread in 1961. The pandemic subsided in the 1970s, but continued on a smaller scale. Outbreaks occur across the developing world to the current day. Epidemics occurred after wars, civil unrest, or natural disasters, when water and food supplies had become contaminated with Vibrio cholerae, and also due to crowded living conditions and poor sanitation. Deaths in India between 1817 and 1860 in the first three pandemics of the nineteenth century, are estimated to have exceeded 15 million people. Another 23 million died between 1865 and 1917, during the next three pandemics. Cholera deaths in the Russian Empire during a similar time period exceeded 2 million.

10.3K
20 Oct 2022

Topic Review

Salinity and Turbidity in the Red Sea

Several industrial and scientific underwater applications require high-speed wireless connectivity. Acoustic communications have low data rates and high latency, whereas attenuation in seawater severely limits radio frequency communications. Optical wireless communication is a promising solution, with high transmission rates (up to Gb/s) and little attenuation in water at visible wavelengths.

10.3K
08 Oct 2022

Topic Review Peer Reviewed

Green Building Rating Systems (GBRSs)

Green Building Rating Systems (GBRSs) are typically third-party, voluntary, and market driven standards that measure buildings’ sustainability level by multi-criteria assessment, and encourage the adoption of environmentally, socially and economically sustainable practices in design, construction and operation of buildings (or neighborhoods). GBRSs aim at guiding and assessing the project throughout all its life cycle, thus limiting the negative impact on the environment, as well as on the building occupants’ health and well-being, and even reducing operational costs. Hundreds of GBRSs are now available worldwide, varying in approaches, application processes, and evaluation metrics. BREEAM, CASBEE, Green Star and LEED are among the most applied worldwide. Despite some differences, they all adhere to the same general evaluation structure: project performances ares measured using a set of relevant indicators, grouped per topics such as water management, energy use, materials, site qualities. Each assessed requirement is assigned a score/judgment, the total of which determines the level of sustainability achieved. In addition to regular updates, a current trend is to improve the effectiveness of protocols, making them more comprehensive and accurate, while keeping them easy to use.

10.3K
13 Apr 2022

Topic Review

Starlink (Satellite Constellation)

Starlink is a satellite constellation being constructed by American company SpaceX to provide satellite Internet access. The constellation will consist of thousands of mass-produced small satellites, working in combination with ground transceivers. SpaceX also plans to sell some of the satellites for military, scientific or exploratory purposes. (As of January 2020), SpaceX has deployed 182 satellites. They plan to deploy 60 more per Falcon 9 launch, with launches as often as every two weeks after late 2019. In total, nearly 12,000 satellites will be deployed by the mid-2020s, with a possible later extension to 42,000. The initial 12,000 satellites are planned to orbit in three orbital shells: first placing approximately 1,600 in a 550-kilometer-altitude (340 mi) shell, then approximately 2,800 Ku- and Ka-band spectrum satellites at 1,150 km (710 mi) and approximately 7,500 V-band satellites at 340 km (210 mi). Commercial operation could begin in 2020. Concerns have been raised about the long-term danger of space junk resulting from placing thousands of satellites in orbits above 1,000 kilometres (620 mi) and a possible impact on astronomy, although SpaceX is reportedly attempting to solve the issue. The total cost of the decade-long project to design, build and deploy the constellation was estimated by SpaceX in May 2018 to be about US$10 billion. Product development began in 2015, with the first two prototype test-flight satellites launched in February 2018. A second set of test satellites and the first large deployment of a piece of the constellation occurred on 24 May 2019 (UTC) when the first 60 operational satellites were launched. The SpaceX satellite development facility in Redmond, Washington, houses the Starlink research, development, manufacturing and on-orbit control operations.

10.3K
11 Nov 2022

Topic Review

IQ and the Wealth of Nations

IQ and the Wealth of Nations is a 2002 book by psychologist Richard Lynn and political scientist Tatu Vanhanen. The authors argue that differences in national income (in the form of per capita gross domestic product) are correlated with differences in the average national intelligence quotient (IQ). They further argue that differences in average national IQs constitute one important factor, but not the only one, contributing to differences in national wealth and rates of economic growth. The book has drawn widespread criticism from other academics. Critiques have included questioning of the methodology used, the incompleteness of the data, and the conclusions drawn from the analysis. The 2006 book IQ and Global Inequality is a follow-up to IQ and the Wealth of Nations by the same authors.

10.3K
14 Oct 2022

Topic Review

Compact Cassette

The Compact Audio Cassette (CAC) or Musicassette (MC), also commonly called the cassette tape or simply tape or cassette, is an analog magnetic tape recording format for audio recording and playback. It was developed by Philips in Hasselt, Belgium, and released in 1962. Compact cassettes come in two forms, either already containing content as a prerecorded cassette, or as a fully recordable "blank" cassette. Both forms are reversible by the user. The compact cassette technology was originally designed for dictation machines, but improvements in fidelity led the Compact Cassette to supplant the Stereo 8-track cartridge and reel-to-reel tape recording in most non-professional applications. Its uses ranged from portable audio to home recording to data storage for early microcomputers. The first cassette player (although mono) designed for use in car dashboards was introduced in 1968. Between the early 1970s and the early 2000s, the cassette was one of the two most common formats for prerecorded music, first alongside the LP record and later the compact disc (CD). Compact Cassettes contain two miniature spools, between which the magnetically coated, polyester-type plastic film (magnetic tape) is passed and wound. These spools and their attendant parts are held inside a protective plastic shell which is 4 by 2.5 by 0.5 inches (10 cm × 6.3 cm × 1.3 cm) at its largest dimensions. The tape itself was commonly referred to as "eighth-inch" tape, supposedly 1⁄8 inches wide, but it was slightly larger: 0.15 inches (3.81 mm). Two stereo pairs of tracks (four total) or two monaural audio tracks are available on the tape; one stereo pair or one monophonic track is played or recorded when the tape is moving in one direction and the second (pair) when moving in the other direction. This reversal is achieved either by flipping the cassette, or by the reversal of tape movement ("auto-reverse") when the mechanism detects that the tape has come to an end.

10.3K
18 Oct 2022

Topic Review

In science fiction and in the beliefs of ufology, a Venusian (/vɪˈnjuːʒən, -ʃən/) or Venerian is a native inhabitant of the planet Venus. Many science fiction writers have imagined what extraterrestrial life on Venus might be like.

10.3K
21 Oct 2022

Topic Review

Photoplethysmography Sensors

The rapid advances in human-friendly and wearable photoplethysmography (PPG) sensors have facilitated the continuous and real-time monitoring of physiological conditions, enabling self-health care without being restricted by location.

10.3K
27 Apr 2021

Topic Review

A paternoster (/ˈpeɪtərˈnɒstər/, /ˈpɑː-/, or /ˈpæ-/) or paternoster lift is a passenger elevator which consists of a chain of open compartments (each usually designed for two persons) that move slowly in a loop up and down inside a building without stopping. Passengers can step on or off at any floor they like. The same technique is also used for filing cabinets to store large amounts of (paper) documents or for small spare parts. The much smaller belt manlift which consists of an endless belt with steps and rungs but no compartments is also sometimes called a paternoster. The name paternoster ("Our Father", the first two words of the Lord's Prayer in Latin) was originally applied to the device because the elevator is in the form of a loop and is thus similar to rosary beads used as an aid in reciting prayers. The construction of new paternosters was stopped in the mid-1970s due to safety concerns, but public sentiment has kept many of the remaining examples open. By far most remaining paternosters are in Europe, with 230 examples in Germany, and 68 in the Czech Republic. Only three have been identified outside Europe: one in Malaysia, one in Sri Lanka, and another in Peru.

10.3K
01 Nov 2022

Topic Review

Declaration of War

A declaration of war is a formal act by which one state goes to war against another. The declaration is a performative speech act (or the signing of a document) by an authorized party of a national government, in order to create a state of war between two or more states. The legality of who is competent to declare war varies between nations and forms of government. In many nations, that power is given to the head of state or sovereign. In other cases, something short of a full declaration of war, such as a letter of marque or a covert operation, may authorise war-like acts by privateers or mercenaries. The official international protocol for declaring war was defined in the Hague Convention (III) of 1907 on the Opening of Hostilities. Since 1945, developments in international law such as the United Nations Charter, which prohibits both the threat and the use of force in international conflicts, have made declarations of war largely obsolete in international relations. The UN Security Council, under powers granted in articles 24 and 25, and Chapter VII of the Charter, may authorize collective action to maintain or enforce international peace and security. Article 51 of the United Nations (UN) Charter also states that: "Nothing in the present Charter shall impair the inherent right to individual or collective self-defence if an armed attack occurs against a state." Few nations have formally declared war upon another since then. In addition to this, non-state or terrorist organizations may claim to or be described as "declaring war" when engaging in violent acts. These declarations may have no legal standing in themselves, but they may still act as a call to arms for supporters of these organizations.

10.2K
11 Dec 2025

Topic Review

Google Home is a line of smart speakers developed by Google under the Google Nest brand. The devices enable users to speak voice commands to interact with services through Google Assistant, the company's virtual assistant. Both in-house and third-party services are integrated, allowing users to listen to music, control playback of videos or photos, or receive news updates entirely by voice. Google Nest devices also have integrated support for home automation, letting users control smart home appliances with their voice command. The first device, Google Home, was released in the United States in November 2016; subsequent product releases occurred globally from 2017–2019. Through software updates to Google Nest devices and Google Assistant, additional functionality has been added over time. For example, multiple speakers can be set up for synchronized playback of music. An update in April 2017 brought multi-user support, allowing the device to distinguish between up to six people by voice. In May 2017, Google announced multiple updates, including: hands-free phone calling at no cost in Canada and the United States; proactive reminders ahead of scheduled events; visual responses on mobile devices or Chromecast-enabled televisions; Bluetooth audio streaming; and the ability to add reminders and calendar appointments. The original Google Home speaker released in November 2016 featured a cylindrical shape with colored status LEDs on top. In October 2017, Google announced two additions to the product lineup, the miniature puck-shaped Google Home Mini and a larger Google Home Max. In October 2018, the company released the Google Home Hub, a smart speaker with a 7-inch touchscreen. In May 2019, Google announced that Google Home devices would be rebranded under the Google Nest banner and unveiled a larger smart display called the Google Nest Hub Max.

10.2K
09 Nov 2022

Topic Review

Concept of Human Flourishing

Human flourishing is a thriving concept, whose use has greatly increased among academic researchers from a variety of fields, from the arts and humanities and psychology to the social and environmental sciences and economics. The rise of the concept was sparked by the positive psychology movement, which based it primarily on subjective and individual well-being; however, it was soon taken up by other currents, such as capabilities theory, reaching many social and collective concerns. Since 2016, the philosophical roots have especially energized the concept, maintaining the expansion of its use in fields related to the application of knowledge and management.

10.2K
01 Mar 2022

Topic Review

The anatomy of the domestic cat is similar to that of other members of the genus Felis.

10.2K
14 Nov 2022

Topic Review

Lithium Recovery via Chemical Precipitation

Lithium is a vital raw material used for a wide range of applications, such as the fabrication of glass, ceramics, pharmaceuticals, and batteries for electric cars. The accelerating electrification transition and the global commitment to decarbonization have caused an increasing demand for lithium. The current supply derived from brines and hard rock ores is not enough to meet the global demand unless alternate resources and efficient techniques to recover this valuable metal are implemented.

10.2K
21 Feb 2023

Topic Review

In philosophy, transcendence is the basic ground concept from the word's literal meaning (from Latin), of climbing or going beyond, albeit with varying connotations in its different historical and cultural stages. It includes philosophies, systems, and approaches that describe the fundamental structures of being, not as an ontology (theory of being), but as the framework of emergence and validation of knowledge of being. "Transcendental" is a word derived from the scholastic, designating the extra-categorical attributes of beings.

10.2K
10 Nov 2022

Topic Review

Prisoners of War in Islam

The rules and regulations concerning prisoners of war in Islam are covered in manuals of Islamic jurisprudence, based upon Islamic teachings, in both the Qur'an and hadith. The historical legal principles governing the treatment of prisoners of war, in shar'iah, Islamic law, (in the traditional madhabs schools of Islamic jurisprudence), was then a significant improvement over the pre-existing norms of society during Muhammad's time (see Early reforms under Islam). Men, women, and children may all be taken as prisoners of war under traditional interpretations of Islamic law. Generally, a prisoner of war could be, at the discretion of the military leader, freed, ransomed, exchanged for Muslim prisoners, or kept in bondage. In earlier times, the ransom sometimes took an educational dimension, where a literate prisoner of war could secure his or her freedom by teaching ten Muslims to read and write. Some Muslim scholars hold that a prisoner may not be ransomed for gold or silver, but may be exchanged for Muslim prisoners.

10.2K
23 Oct 2022

Topic Review

SpyCatcher-SpyTag System

The SpyCatcher-SpyTag system was developed as a method for protein ligation. It is based on a modified domain from a Streptococcus pyogenes surface protein (SpyCatcher), which recognizes a cognate 13-amino-acid peptide (SpyTag). Upon recognition, the two form a covalent isopeptide bond between the side chains of a lysine in SpyCatcher and an aspartate in SpyTag. This technology has been used, among other applications, to create covalently stabilized multi-protein complexes, for modular vaccine production, and to label proteins (e.g., for microscopy).

10.2K
19 Oct 2022

Topic Review

Barcelona (/ˌbɑːrsəˈloʊnə/ BAR-sə-LOH-nə, Catalan: [bəɾsəˈlonə], Spanish: [baɾθeˈlona]) is a city in Spain . It is the capital and largest city of Catalonia, as well as the second most populous municipality of Spain. With a population of 1.6 million within city limits, its urban area extends to numerous neighbouring municipalities within the Province of Barcelona and is home to around 4.8 million people, making it the sixth most populous urban area in the European Union after Paris, London, Madrid, the Ruhr area and Milan. It is one of the largest metropolises on the Mediterranean Sea, located on the coast between the mouths of the rivers Llobregat and Besòs, and bounded to the west by the Serra de Collserola mountain range, the tallest peak of which is 512 metres (1,680 feet) high. Founded as a Roman city, in the Middle Ages Barcelona became the capital of the County of Barcelona. After merging with the Kingdom of Aragon, Barcelona continued to be an important city in the Crown of Aragon as an economic and administrative centre of this Crown and the capital of the Principality of Catalonia. Barcelona has a rich cultural heritage and is today an important cultural centre and a major tourist destination. Particularly renowned are the architectural works of Antoni Gaudí and Lluís Domènech i Montaner, which have been designated UNESCO World Heritage Sites. The headquarters of the Union for the Mediterranean are located in Barcelona. The city is known for hosting the 1992 Summer Olympics as well as world-class conferences and expositions and also many international sport tournaments. Barcelona is one of the world's leading tourist, economic, trade fair and cultural centres, and its influence in commerce, education, entertainment, media, fashion, science, and the arts all contribute to its status as one of the world's major global cities. It is a major cultural and economic centre in southwestern Europe, 24th in the world (before Zürich, after Frankfurt) and a financial centre. In 2008 it was the fourth most economically powerful city by GDP in the European Union and 35th in the world with GDP amounting to €177 billion. In 2012 Barcelona had a GDP of $170 billion; and it was leading Spain in employment rate in that moment. In 2009 the city was ranked Europe's third and one of the world's most successful as a city brand. In the same year the city was ranked Europe's fourth best city for business and fastest improving European city, with growth improved by 17% per year, and the city has been experiencing strong and renewed growth for the past three years. Since 2011 Barcelona has been a leading smart city in Europe. Barcelona is a transport hub, with the Port of Barcelona being one of Europe's principal seaports and busiest European passenger port, an international airport, Barcelona–El Prat Airport, which handles over 40 million passengers per year, an extensive motorway network, and a high-speed rail line with a link to France and the rest of Europe.

10.2K
16 Nov 2022

Topic Review

Ohaguro (お歯黒) is a custom of dyeing one's teeth black. It was most popular in Japan until the Meiji era. Tooth painting is also known and practiced in the southeastern parts of China , Pacific Islands and Southeast Asia. Dyeing is mainly done by married women, though occasionally men do it as well. It was also beneficial, as it prevented tooth decay, in a similar fashion to modern dental sealants.

10.2K
19 Oct 2022

Topic Review

Adult Wistar Rats

Rats are considered adults from 2 to 5 months. During this period, they are used for experimentation in physiology and pharmacology. Adult rats, depending on their age, can be in a different physiological state, which can influence the results of experiments carried out on them. Despite this, age-related changes in adult rats have not yet been examined. Our results showed that as male and female rats progressed from 2 to 5 months of age there was a decrease in the level of motor and exploratory activities, and an increase in the level of anxiety-like behaviour. Age-related changes were dependent upon initial individual characteristics of behaviour. For example, animals that demonstrated high motor activity at 2 months become significantly less active by 5 months, and animals that showed a low level of anxiety at 2 months become more anxious by 5 months. Low-activity and high-anxiety rats did not show any significant age-related changes from 2 to 5 months of age.

10.2K
23 Aug 2021

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