|
School Shooting
A school shooting is an Gun violence, armed attack at an educational institution, such as a primary school, secondary school, high school or university, involving the use of a firearm. Many school shootings are also categorized as mass shootings due to multiple casualties. The phenomenon is most widespread in the United States, which has the highest number of school-related shootings, although school shootings take place elsewhere in the world. Especially in the United States, school shootings have sparked a political debate over gun violence, Zero tolerance (schools), zero tolerance policies, right to bear arms, gun rights and gun control. According to studies, factors behind school shooting include easy access to firearms, family dysfunction, lack of family supervision, and mental illness among many other psychological issues. Among the topmost motives of attackers were: bullying/persecution/threatened (75%) and revenge (61%), while 54% reported having numerous reasons. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alan Lipman
Alan J. Lipman is an American clinical psychologist and musician, who is currently a professor of psychiatry and behavioral sciences at the George Washington University Medical Center and the director of the Center for the Study of Violence. He is based in Washington, D.C., studying causes of violence in adults and youth, mass and school shootings, murder and homicide. Lipman is also a commentator on the areas of violence, mass and school shootings, homicide, terrorism, psychology and psychotherapy, having served as commentator for various national media outlets. Lipman holds the M.A. and Ph.D. degrees in Clinical Psychology from Temple University as well as Juris Doctor from Georgetown University Law Center. As a musician, he performs credited as X-Patriate. Career Lipman has served as a professor at Georgetown University, The George Washington University, and Rutgers University, and has also held positions at The Hospital of the University of Pennsylvania and Yale Psychiatr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific American
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it, with more than 150 Nobel Prize-winners being featured since its inception. In print since 1845, it is the oldest continuously published magazine in the United States. ''Scientific American'' is owned by Springer Nature, which is a subsidiary of Holtzbrinck Publishing Group. History ''Scientific American'' was founded by inventor and publisher Rufus Porter (painter), Rufus Porter in 1845 as a four-page weekly newspaper. The first issue of the large-format New York City newspaper was released on August 28, 1845. Throughout its early years, much emphasis was placed on reports of what was going on at the United States Patent and Trademark Office, U.S. Patent Office. It also reported on a broad range of inventions including perpetual motion machines, an 1860 devi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apoptosis
Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biology), morphology) and death. These changes include Bleb (cell biology), blebbing, Plasmolysis, cell shrinkage, Karyorrhexis, nuclear fragmentation, Pyknosis, chromatin condensation, Apoptotic DNA fragmentation, DNA fragmentation, and mRNA decay. The average adult human loses 50 to 70 1,000,000,000, billion cells each day due to apoptosis. For the average human child between 8 and 14 years old, each day the approximate loss is 20 to 30 billion cells. In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is a highly regulated and controlled process that confers advantages during an organism's life cycle. For example, the separation of fingers and toes in a developing human embryo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapses
In the nervous system, a synapse is a structure that allows a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending on the mechanism of signal transmission between neurons. In the case of electrical synapses, neurons are coupled bidirectionally with each other through gap junctions and have a connected cytoplasmic milieu. These types of synapses are known to produce synchronous network activity in the brain, but can also result in complicated, chaotic network level dynamics. Therefore, signal directionality cannot always be defined across electrical synapses. Chemical synapses, on the other hand, communicate through neurotransmitters released from the presynaptic neuron into the synaptic cleft. Upon release, these neurotransmitters bind to specific receptors on the postsynaptic membrane, inducing an electrical or chemical response in the target neuron. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurons
A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural network in the nervous system. They are located in the nervous system and help to receive and conduct impulses. Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap. Neurons are the main components of nervous tissue in all Animalia, animals except sponges and placozoans. Plants and fungi do not have nerve cells. Molecular evidence suggests that the ability to generate electric signals first appeared in evolution some 700 to 800 million years ago, during the Tonian period. Predecessors of neurons were the peptidergic secretory cells. They eventually ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axons
An axon (from Greek ἄξων ''áxōn'', axis) or nerve fiber (or nerve fibre: see spelling differences) is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands. In certain sensory neurons ( pseudounipolar neurons), such as those for touch and warmth, the axons are called afferent nerve fibers and the electrical impulse travels along these from the periphery to the cell body and from the cell body to the spinal cord along another branch of the same axon. Axon dysfunction can be the cause of many inherited and acquired neurological disorders that affect both the peripheral and central neurons. Nerve fibers are classed into three types group A nerve fibers, group B nerve fibers, and group C nerve fibers. Groups A and B are myelinated, and group C are unmyelina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nervous System
In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. The nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. Nervous tissue first arose in Ediacara biota, wormlike organisms about 550 to 600 million years ago. In Vertebrate, vertebrates, it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers, or axons, that connect the CNS to every other part of the body. Nerves that transmit signals from the brain are called motor nerves (efferent), while those nerves that transmit information from the body to the CNS are called sensory nerves (aff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptic Pruning
Synaptic pruning is the process of synapse elimination or weakening. Though it occurs throughout the lifespan of a mammal, the most active period of synaptic pruning in the development of the nervous system occurs between early childhood and the onset of puberty in many mammals, including humans. Pruning starts near the time of birth and continues into the late-20s. During elimination of a synapse, the axon withdraws or dies off, and the dendrite decays and die off. Synaptic pruning was traditionally considered to be complete by the time of sexual maturation, but magnetic resonance imaging studies have discounted this idea. The infant brain will increase in size by a factor of up to 5 by adulthood. Two factors contribute to this growth: the growth of synaptic connections between neurons and the myelination of nerve fibers. The total number of neurons, however, remains approximately the same, containing approximately 86 (± 8) billion neurons. After adolescence, the volume of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain Development
The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head ( cephalization), usually near organs for special senses such as vision, hearing, and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing that information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity and endocrine system). While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a vesicular enlargement at the rostral end of the neural tube, with centralized control over all body segments. All vertebrate brains can be embryonically divided into three parts: the forebrain (prosencephalon, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aggression
Aggression is behavior aimed at opposing or attacking something or someone. Though often done with the intent to cause harm, some might channel it into creative and practical outlets. It may occur either reactively or without provocation. In humans, aggression can be caused by various triggers. For example, built-up frustration due to blocked goals or perceived disrespect. Human aggression can be classified into direct and indirect aggression; while the former is characterized by physical or verbal behavior intended to cause harm to someone, the latter is characterized by behavior intended to harm the social relations of an individual or group. In definitions commonly used in the social sciences and behavioral sciences, aggression is an action or response by an individual that delivers something unpleasant to another person. Some definitions include that the individual must intend to harm another person. In an interdisciplinary perspective, aggression is regarded as "an ensem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Violence
Violence is characterized as the use of physical force by humans to cause harm to other living beings, or property, such as pain, injury, disablement, death, damage and destruction. The World Health Organization (WHO) defines violence as "the intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community, which either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment, or deprivation"; it recognizes the need to include violence not resulting in injury or death. Categories The World Health Organization (WHO) divides violence into three broad categories: self-directed, interpersonal, and collective. This categorization differentiates between violence inflicted to and by oneself, by another individual or a small group, and by larger groups such as states. Alternatively, violence can primarily be classified as either instrumental or hostile. Self-in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
