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Concept: Weapon


The horrific loss of life at Sandy Hook Elementary School in Newtown, Connecticut, in December 2012 has prompted a national conversation about guns and mental illness in the United States.This tragedy occurred less than 6 months after 70 people were shot in a movie theater in Colorado and after highly publicized mass shootings in Arizona and at Virginia Tech. These four events share two common characteristics: all four shooters were apparently mentally ill, and all four used guns with large-capacity magazines, allowing them to fire multiple rounds of ammunition without reloading. As policymakers consider options to reduce gun violence, they . . .

Concepts: U.S. state, Mental disorder, Mental illness, Projectile, Firearm, Colorado, Weapon, Fairfield County, Connecticut


Projectile weapons (i.e. those delivered from a distance) enhanced prehistoric hunting efficiency by enabling higher impact delivery and hunting of a broader range of animals while reducing confrontations with dangerous prey species. Projectiles therefore provided a significant advantage over thrusting spears. Composite projectile technologies are considered indicative of complex behavior and pivotal to the successful spread of Homo sapiens. Direct evidence for such projectiles is thus far unknown from >80,000 years ago. Data from velocity-dependent microfracture features, diagnostic damage patterns, and artifact shape reported here indicate that pointed stone artifacts from Ethiopia were used as projectile weapons (in the form of hafted javelin tips) as early as >279,000 years ago. In combination with the existing archaeological, fossil and genetic evidence, these data isolate eastern Africa as a source of modern cultures and biology.

Concepts: Human, Africa, Projectile, Archaeology, Ammunition, Weapon, Missile, Arrow


BACKGROUND:Many scientific studies have shown that the mere presence of guns can increase aggression, an effect dubbed the “weapons effect.” The current research examines a potential source of the weapons effect: guns depicted in top-selling films.METHODS:Trained coders identified the presence of violence in each 5-minute film segment for one-half of the top 30 films since 1950 and the presence of guns in violent segments since 1985, the first full year the PG-13 rating (age 13+) was used. PG-13-rated films are among the top-selling films and are especially attractive to youth.RESULTS:Results found that violence in films has more than doubled since 1950, and gun violence in PG-13-rated films has more than tripled since 1985. When the PG-13 rating was introduced, these films contained about as much gun violence as G (general audiences) and PG (parental guidance suggested for young children) films. Since 2009, PG-13-rated films have contained as much or more violence as R-rated films (age 17+) films.CONCLUSIONS:Even if youth do not use guns, these findings suggest that they are exposed to increasing gun violence in top-selling films. By including guns in violent scenes, film producers may be strengthening the weapons effect and providing youth with scripts for using guns. These findings are concerning because many scientific studies have shown that violent films can increase aggression. Violent films are also now easily accessible to youth (eg, on the Internet and cable). This research suggests that the presence of weapons in films might amplify the effects of violent films on aggression.

Concepts: Aggression, Violence, Film, Projectile, Weapon, Gun, Motion Picture Association of America film rating system, Indiana Jones and the Temple of Doom


Alternative reproductive tactics in animals are commonly associated with distinct male phenotypes resulting in polymorphism of sexually selected weapons such as horns and spines. Typically, morphs are divided between small (unarmed) and large (armed) males according to one or more developmental thresholds in association with body size. Here, we describe remarkable weapon trimorphism within a single species, where two exaggerated weapon morphs and a third morph with reduced weaponry are present. Male Pantopsalis cheliferoides harvestmen display exaggerated chelicerae (jaws) which are highly variable in length among individuals. Across the same body size spectrum, however, some males belong to a distinct second exaggerated morph which possesses short, broad chelicerae. Multiple weapon morphs in a single species is a previously unknown phenomenon and our findings have significant implications for understanding weapon diversity and maintenance of polymorphism. Specifically, this species will be a valuable model for testing how weapons diverge by being able to test directly for the circumstances under which a certain weapon type is favoured and how weapon shape relates to performance.

Concepts: Human, Reproduction, Chromosome, Nuclear weapon, Weapon


This editorial discusses the pros and cons of community treatment orders (CTOs) from the perspective of community general adult psychiatry. There is little scientific evidence supporting the application of CTOs. Preconditions of a CTO to work are likely to be met by few patients. The time for the application of a CTO may be better spent for patient-centred care until there is sufficient new and robust evidence that identifies the patients that might profit.

Concepts: Doctor-patient relationship, Psychiatry, Social sciences, Combat, Weapon, Jimmy Jam and Terry Lewis, Infantry


Contests among individuals over mating opportunities are common across diverse taxa, yet physical conflict is relatively rare. Due to the potentially fatal consequences of physical fighting, most animals employ mechanisms of conflict resolution involving signalling and ritualistic assessment. Here we provide the first evidence of ubiquitous escalated fighting in grasshoppers. The chameleon grasshopper (Kosciuscola tristis) is an Australian alpine specialist, in which males engage in highly aggressive combat over ovipositing females. We describe discrete agonistic behaviours including mandible flaring, mounting, grappling, kicking and biting, and their use depending on the individual’s role as challenger or defender. We show that male role predicts damage, with challengers being more heavily damaged than males defending females (defenders). Challengers also possess wider mandibles than defenders, but are similar in other metrics of body size. Our data suggest that fights escalate between males matched in body size and that mandibles are used as weapons in this species. This system represents an exciting opportunity for future research into the evolution of costly fighting behaviour in an otherwise placid group.

Concepts: Male, Reproduction, Female, Sex, Grasshopper, Combat, Weapon


The shapes of sexually selected weapons differ widely among species, but the drivers of this diversity remain poorly understood. Existing explanations suggest weapon shapes reflect structural adaptations to different fighting styles, yet explicit tests of this hypothesis are lacking. We constructed finite element models of the horns of different rhinoceros beetle species to test whether functional specializations for increased performance under species-specific fighting styles could have contributed to the diversification of weapon form. We find that horns are both stronger and stiffer in response to species-typical fighting loads and that they perform more poorly under atypical fighting loads, which suggests weapons are structurally adapted to meet the functional demands of fighting. Our research establishes a critical link between weapon form and function, revealing one way male-male competition can drive the diversification of animal weapons.

Concepts: Natural selection, Function, Structure, Population genetics, Adaptation, Charles Darwin, Combat, Weapon


Fatal and nonfatal injuries resulting from gun violence remain a persistent problem in the United States. The available research suggests that gun violence diffuses among people and across places through social relationships. Understanding the relationship between gun violence within social networks and individual gun violence risk is critical in preventing the spread of gun violence within populations. This systematic review examines the existing scientific evidence on the transmission of gun and other weapon-related violence in household, intimate partner, peer, and co-offending networks. Our review identified 16 studies published between 1996 and 2015 that suggest that exposure to a victim or perpetrator of violence in one’s interpersonal relationships and social networks increases the risk of individual victimization and perpetration. Formal network analyses find high concentrations of gun violence in small networks and that exposure to gun violence in one’s networks is highly correlated with one’s own probability of being a gunshot victim. Physical violence by parents and weapon use by intimate partners also increase risk for victimization and perpetration. Additional work is needed to better characterize the mechanisms through which network exposures increase individual risk for violence and to evaluate interventions aimed at disrupting the spread of gun and other weapon violence in high-risk social networks.

Concepts: Family, United States, Sociology, Interpersonal relationship, Social psychology, Social network, Intimate relationship, Weapon


The goal of this study was to assess the frequency, nature, and outcome of weapon use in intimate partner violence (IPV) and to assess compliance with related gun policies.

Concepts: Domestic violence, Weapon, Gun


To report the prevalence of weapons involved in the victimization of youth with particular emphasis on weapons with a “high lethality risk” and how such exposure fits into the broader victimization and life experiences of children and adolescents.

Concepts: Nuclear weapon, Security, Weapon, Weapons