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Topic Review
Sex Ratio
The sex ratio is the ratio of males to females in a population. In most sexually reproducing species, the ratio tends to be 1:1. This tendency is explained by Fisher's principle. For various reasons, however, many species deviate from anything like an even sex ratio, either periodically or permanently. Examples include parthenogenic species, periodically mating organisms such as aphids, some eusocial wasps such as Polistes fuscatus and Polistes exclamans, bees, ants, and termites. The human sex ratio is of particular interest to anthropologists and demographers. In human societies, however, sex ratios at birth may be considerably skewed by factors such as the age of mother at birth, and by sex-selective abortion and infanticide. Exposure to pesticides and other environmental contaminants may be a significant contributing factor as well. As of 2014, the global sex ratio at birth is estimated at 107 boys to 100 girls (1,000 boys per 934 girls).
  • 6.4K
  • 19 Oct 2022
Topic Review
Void
Cosmic voids are vast spaces between filaments (the largest-scale structures in the universe), which contain very few or no galaxies. The cosmological evolution of the void regions differs drastically from the evolution of the Universe as a whole: there is a long stage when the curvature term dominates, which prevents the formation of galaxy clusters and massive galaxies. Hence, although even the emptiest regions of voids contain more than ~15% of the average matter density of the Universe, the voids look almost empty for an observer. Voids typically have a diameter of 10 to 100 megaparsecs (30 to 300 million light years); particularly large voids, defined by the absence of rich superclusters, are sometimes called supervoids. They were first discovered in 1978 in a pioneering study by Stephen Gregory and Laird A. Thompson at the Kitt Peak National Observatory. Voids are believed to have been formed by baryon acoustic oscillations in the Big Bang, collapses of mass followed by implosions of the compressed baryonic matter. Starting from initially small anisotropies from quantum fluctuations in the early universe, the anisotropies grew larger in scale over time. Regions of higher density collapsed more rapidly under gravity, eventually resulting in the large-scale, foam-like structure or "cosmic web" of voids and galaxy filaments seen today. Voids located in high-density environments are smaller than voids situated in low-density spaces of the universe. Voids appear to correlate with the observed temperature of the cosmic microwave background (CMB) because of the Sachs–Wolfe effect. Colder regions correlate with voids and hotter regions correlate with filaments because of gravitational redshifting. As the Sachs–Wolfe effect is only significant if the universe is dominated by radiation or dark energy, the existence of voids is significant in providing physical evidence for dark energy.
  • 6.4K
  • 18 Oct 2022
Topic Review
Mechanism of Cotton Combustion
As a cellulose-based polymer, the combustion of cotton is an exothermic oxidation process that takes place upon heating, consuming flammable gases, liquids, and solid residues produced during the pyrolysis of the textile material, thus generating heat.
  • 6.4K
  • 27 Jul 2023
Topic Review
Philosophy of History
Philosophy of history is the philosophical study of history and the past. The term was coined by Voltaire.
  • 6.4K
  • 19 Oct 2022
Topic Review
Artificial Island Developments
Artificial island development (AID) to tackle rampant urbanization on scarce land puts all marine biodiversity at huge risk and is recognized as a global conservation issue worldwide.
  • 6.4K
  • 16 May 2022
Topic Review
Make
In software development, Make is a build automation tool that automatically builds executable programs and libraries from source code by reading files called Makefiles which specify how to derive the target program. Though integrated development environments and language-specific compiler features can also be used to manage a build process, Make remains widely used, especially in Unix and Unix-like operating systems. Besides building programs, Make can be used to manage any project where some files must be updated automatically from others whenever the others change.
  • 6.4K
  • 28 Sep 2022
Topic Review
Porridge
Porridge (historically also spelled porage, porrige, or parritch) is a food commonly eaten as a breakfast cereal dish, made by boiling ground, crushed or chopped starchy plants—typically grain—in water or milk. It is often cooked or served with added flavorings such as sugar, honey, (dried) fruit or syrup to make a sweet cereal, or it can be mixed with spices or vegetables to make a savoury dish. It is usually served hot in a bowl, depending on its consistency. Oat porridge, or oatmeal, is one of the most common types of porridge. Gruel is a thinner version of porridge.
  • 6.4K
  • 02 Nov 2022
Topic Review
Jallianwala Bagh: Roots of a Historic Massacre
Today, April 13th, 2025, marks the 106th anniversary of the Jallianwala Bagh Massacre, a day etched in the collective memory of India as a brutal and defining moment in its struggle for independence.
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  • 13 Apr 2025
Topic Review
Kübler-Ross Model
The Kübler-Ross model, or the Five Stages of Grief, postulates a series of emotions experienced by terminally ill patients prior to death, or people who have lost a loved one, wherein the five stages are: denial, anger, bargaining, depression, and acceptance. Although commonly referenced in popular media, the existence of these stages has not been empirically demonstrated and the model is not considered helpful in explaining the grieving process. It is considered to be of historical value but outdated in scientific terms and in clinical practice. The model was first introduced by Swiss-American psychiatrist Elisabeth Kübler-Ross in her 1969 book On Death and Dying, and was inspired by her work with terminally ill patients. Motivated by the lack of instruction in medical schools on the subject of death and dying, Kübler-Ross examined death and those faced with it at the University of Chicago's medical school. Kübler-Ross's project evolved into a series of seminars which, along with patient interviews and previous research, became the foundation for her book. Although Kübler-Ross is commonly credited with creating stage models, earlier bereavement theorists and clinicians such as Erich Lindemann, Collin Murray Parkes, and John Bowlby used similar models of stages of phases as early as the 1940s. Later in her life, Kübler-Ross noted that the stages are not a linear and predictable progression and that she regretted writing them in a way that was misunderstood. "Kübler-Ross originally saw these stages as reflecting how people cope with illness and dying," observed grief researcher Kenneth J. Doka, "not as reflections of how people grieve."
  • 6.4K
  • 03 Nov 2022
Topic Review
Systemic Lupus Erythematosus Pathogenesis
Systemic lupus erythematosus (SLE) is a genetically predisposed, female-predominant disease, characterized by multiple organ damage, that in its most severe forms can be life-threatening. The pathogenesis of SLE is complex and involves cells of both innate and adaptive immunity. The distinguishing feature of SLE is the production of autoantibodies, with the formation of immune complexes that precipitate at the vascular level, causing organ damage. 
  • 6.4K
  • 04 Apr 2023
Topic Review
48,XXYY Syndrome
48,XXYY syndrome is a chromosomal condition that causes infertility, developmental and behavioral disorders, and other health problems in males.
  • 6.4K
  • 23 Dec 2020
Topic Review
Deep Residual Learning for Image Recognition
In 2015, a deep residual network (ResNet) was proposed for image recognition. It is a type of convolutional neural network (CNN) where the input from the previous layer is added to the output of the current layer. Deep Residual Networks have recently been shown to significantly improve the performance of neural networks trained on ImageNet, with results beating all previous methods on this dataset by large margins in the image classification task. 
  • 6.4K
  • 22 Sep 2022
Topic Review
Islamist Shi'ism
Islamist Shi'ism (Persian: تشیع اخوانی‎) is a denomination of Twelver Shia Islam greatly inspired by the Sunni Muslim Brotherhood ideologies and politicized version of Ibn Arabi's mysticism. It sees Islam as a political system and differs from the other mainstream Usuli and Akhbari groups in favoring the idea of formation of Islamist state in occultation of the twelfth Imam. Hadi Khosroshahi was the first person to identify himself as ikhwani (Islamist) Shia. Because of the concept of the hidden Imam, Muhammad al-Mahdi, Shia Islam is inherently secular in the age of occultation, so islamist Shi'ites had to borrow ideas from Sunni islamists and adjust them with Shi'i outlook. Islamism (Persian: اخوانی گری‎) (also often called political Islam or Islamic fundamentalism) is a political ideology which posits that modern states and regions should be reconstituted in constitutional, economic and judicial terms, in accordance with what is conceived as a revival or a return to authentic Islamic practice in its totality. Ideologies dubbed Islamist may advocate a "revolutionary" strategy of Islamizing society through exercise of state power, or alternately a "reformist" strategy to re-Islamizing society through grassroots social and political activism. Islamists may emphasize the implementation of sharia, pan-Islamic political unity, the creation of Islamic states, or the outright removal of non-Muslim influences; particularly of Western or universal economic, military, political, social, or cultural nature in the Muslim world; that they believe to be incompatible with Islam and a form of Western neocolonialism. Some analysts such as Graham E. Fuller describe it as a form of identity politics, involving "support for (Muslim) identity, authenticity, broader regionalism, revivalism, (and) revitalization of the community." The term itself is not popular among many Islamists who believe it inherently implies violent tactics, human rights violations, and political extremism when used by Western mass media. Some authors prefer the term "Islamic activism", while Islamist political figures such as Rached Ghannouchi use the term "Islamic movement" rather than Islamism. Central and prominent figures in 20th-century Islamism include Sayyid Rashid Rida, Hassan al-Banna, Sayyid Qutb, Abul A'la Maududi, Hasan al-Turabi,and Ruhollah Khomeini.
  • 6.4K
  • 20 Oct 2022
Topic Review
Hypocrisy
Hypocrisy is the contrivance of a false appearance of virtue or goodness, while concealing real character or inclinations, especially with respect to religious and moral beliefs; hence, in a general sense, hypocrisy may involve dissimulation, pretense, or a sham. Hypocrisy is the practice of engaging in the same behavior or activity for which one criticizes another. In moral psychology, it is the failure to follow one's own expressed moral rules and principles. According to British political philosopher David Runciman, "Other kinds of hypocritical deception include claims to knowledge that one lacks, claims to a consistency that one cannot sustain, claims to a loyalty that one does not possess, claims to an identity that one does not hold". American political journalist Michael Gerson says that political hypocrisy is "the conscious use of a mask to fool the public and gain political benefit". Hypocrisy has been a subject of folk wisdom and wisdom literature from the beginnings of human history. Increasingly, since the 1980s, it has also become central to studies in behavioral economics, cognitive science, cultural psychology, decision making, ethics, evolutionary psychology, moral psychology, political sociology, positive psychology, social psychology, and sociological social psychology.
  • 6.4K
  • 21 Nov 2022
Topic Review
Role of Granulosa and Theca Cells in PCOS
Polycystic ovary syndrome (PCOS) is the most common heterogeneous endocrine disorder among women of reproductive age. The pathogenesis of PCOS remains elusive and there is evidence suggesting the potential contribution of genetic interactions or predispositions combined with environmental factors.
  • 6.4K
  • 16 Jan 2023
Topic Review
Red Panda
The Red Panda (Ailurus fulgens) is a charismatic and endangered mammal native to the eastern Himalayas and southwestern China. With its distinctive red fur, bushy tail, and cat-like face, the Red Panda is often described as a living symbol of biodiversity conservation. Despite its name, the Red Panda is not closely related to the Giant Panda but shares similar bamboo-dominated habitats and a diet primarily consisting of bamboo leaves and shoots.
  • 6.4K
  • 28 Feb 2024
Topic Review
Social Media and the Arab Spring
The role of social media in the Arab Spring, a revolutionary wave of demonstrations and protests in the Middle East and North Africa between 2010 and 2012, remains a highly debated subject. Uprisings occurred both in states with very high levels of Internet usage (such as Bahrain, with 88% of its population online in 2011) and in states with some of the lowest levels of Internet penetration (such as Yemen and Libya).
  • 6.4K
  • 09 Oct 2022
Topic Review
E-reader
An e-reader, also called an e-book reader or e-book device, is a mobile electronic device that is designed primarily for the purpose of reading digital e-books and periodicals. Any device that can display text on a screen may act as an e-reader; however, specialized e-reader devices may optimize portability, readability, and battery life for this purpose. Their main advantage over printed books is portability. This is because an e-reader is capable of holding thousands of books while weighing less than one book, and the convenience provided due to add-on features.
  • 6.4K
  • 21 Oct 2022
Topic Review
Brahmā (Buddhism)
Brahmā is a leading god (deva) and heavenly king in Buddhism. He was adopted from other Indian religions such as Hinduism that considered him a protector of teachings (dharmapala), and he is never depicted in early Buddhist texts as a creator god. In Buddhist tradition, it was the deity Brahma Sahampati who appeared before the Buddha and urged him to teach, once the Buddha attained enlightenment but was unsure if he should teach his insights to anyone. Brahma is a part of the Buddhist cosmology, and lords over the heavenly realm of rebirth called the Brahmaloka – the most sought after realm for afterlife and reincarnation in Buddhist traditions. Brahma is generally represented in Buddhist culture as a god with four faces and four arms, and variants of him are found in both Theravada and Mahayana Buddhist cultures. The origins of Brahma in Buddhism and other Indian religions are uncertain, in part because several related words such as one for metaphysical Ultimate Reality (Brahman), and priest (Brahmin) are found in the Vedic literature. According to KN Jayatilleke, the Rigveda expresses skepticism about major deities such as Indra whether he even exists, as well as whether the universe has any creator and can this ever be known, as evidenced in its eighth and tenth book, particularly in its Nasadiya Sukta. The late Vedic hymns had begun inquiring the nature of true and valid knowledge, empirical verification and absolute reality. The early Upanishads built upon this theme, while in parallel there emerged Buddhism, Jainism and other skeptical traditions. Buddhism used the term Brahma to deny a creator as well as to delegate him (and other deities such as Indra) as less important than the Buddha. In Hindu literature, one of the earliest mention of deity Brahma with Vishnu and Shiva is in the fifth Prapathaka (lesson) of the Maitrayaniya Upanishad, probably composed in late 1st millennium BCE, after the rise of Buddhism. The spiritual concept of Brahman is far older, and some scholars suggest deity Brahma may have emerged as a personal conception and icon with attributes (saguna version) of the impersonal universal principle called Brahman. The Buddhists attacked the concept of Brahma, states Gananath Obeyesekere, and thereby polemically attacked the Vedic and Upanishadic concept of gender neutral, abstract metaphysical Brahman. This critique of Brahma in early Buddhist texts aim at ridiculing the Vedas, but the same texts simultaneously call metta (loving-kindness, compassion) as the state of union with Brahma. The early Buddhist approach to Brahma was to reject any creator aspect, while retaining the Brahmavihara aspects of Brahma, in the Buddhist value system. Deity Brahma is also found in the samsara doctrine and cosmology of early Buddhism. Brahma is known as Fantian (梵天) in Chinese, Bonten (梵天) in Japanese, Pomch'on in Korean, Phra Phrom in Thai, and Tshangs pa in Tibetan.
  • 6.4K
  • 05 Dec 2022
Topic Review
Perception of Artificial Intelligence by Students
Artificial Intelligence (AI) has become an integral part of people's daily lives and is available on all platforms, from smart homes to smartphones and autonomous cars. Students of economics and business studies at different levels of study have the differences in various aspects of the perception of artificial intelligence. Current college students will soon join a job market where proficiency in working with, developing, and managing AI will be necessary for many positions. Studying AI-related courses has become a necessary trend that offers significant benefits for students’ future career development 
  • 6.3K
  • 16 Jun 2023
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