The Anglo-Saxon migration and the formation of the early English gene pool.

The history of the British Isles and Ireland is characterized by multiple periods of major cultural change, including the influential transformation after the end of Roman rule, which precipitated shifts in language, settlement patterns and material culture1. The extent to which migration from continental Europe mediated these transitions is a matter of long-standing debate2-4. Here we study genome-wide ancient DNA from 460 medieval northwestern Europeans-including 278 individuals from England-alongside archaeological data, to infer contemporary population dynamics. We identify a substantial increase of continental northern European ancestry in early medieval England, which is closely related to the early medieval and present-day inhabitants of Germany and Denmark, implying large-scale substantial migration across the North Sea into Britain during the Early Middle Ages. As a result, the individuals who we analysed from eastern England derived up to 76% of their ancestry from the continental North Sea zone, albeit with substantial regional variation and heterogeneity within sites. We show that women with immigrant ancestry were more often furnished with grave goods than women with local ancestry, whereas men with weapons were as likely not to be of immigrant ancestry. A comparison with present-day Britain indicates that subsequent demographic events reduced the fraction of continental northern European ancestry while introducing further ancestry components into the English gene pool, including substantial southwestern European ancestry most closely related to that seen in Iron Age France5,6.

The wooden artifacts from Schöningen's Spear Horizon and their place in human evolution.

Ethnographic records show that wooden tools played a pivotal role in the daily lives of hunter-gatherers including food procurement tools used in hunting (e.g., spears, throwing sticks) and gathering (e.g. digging sticks, bark peelers), as well as, domestic tools (e.g., handles, vessels). However, wood rarely survives in the archeological record, especially in Pleistocene contexts and knowledge of prehistoric hunter-gatherer lifeways is strongly biased by the survivorship of more resilient materials such as lithics and bones. Consequently, very few Paleolithic sites have produced wooden artifacts and among them, the site of Schöningen stands out due to its number and variety of wooden tools. The recovery of complete wooden spears and throwing sticks at this 300,000-y-old site (MIS 9) led to a paradigm shift in the hunter vs. scavenger debate. For the first time and almost 30 y after their discovery, this study introduces the complete wooden assemblage from Schöningen 13 II-4 known as the Spear Horizon. In total, 187 wooden artifacts could be identified from the Spear Horizon demonstrating a broad spectrum of wood-working techniques, including the splitting technique. A minimum of 20 hunting weapons is now recognized and two newly identified artifact types comprise 35 tools made on split woods, which were likely used in domestic activities. Schöningen 13 II-4 represents the largest Pleistocene wooden artifact assemblage worldwide and demonstrates the key role woodworking had in human evolution. Finally, our results considerably change the interpretation of the Pleistocene lakeshore site of Schöningen.

The language of less-lethal weapons.

It has been over 1 year since we observed the policing of the George Floyd protests in the United States [R. R. Hardeman, E. M. Medina, R. W. Boyd, N. Engl. J. Med. 383, 197-199 (2020)]. Multiple injury reports emerged in medical journals, and the scientific community called for law enforcement to discontinue the use of less-lethal weapons [E. A. Kaske et al., N. Engl. J. Med. 384, 774-775 (2021) and K. A. Olson et al., N. Engl. J. Med. 383, 1081-1083 (2020)]. Despite progress in research, policy change has not followed a similar pace. Although the reasoning for this discrepancy is multifactorial, failure to use appropriate language may be one contributing factor to the challenges faced in updating policies and practices. Here, we detail how language has the potential to influence thinking and decision-making, we discuss how the language of less-lethal weapons minimizes harm, and we provide a framework for naming conventions that acknowledges harm.

Sexually selected weapons can wear out, decreasing their effectiveness in combat.

Sexual selection has resulted in some of the most elaborate traits seen in animals, many of which are used as weapons. These weapons can be incredibly diverse, even within species. Such morphological variation has largely been attributed to the environment in which individuals are reared and their genetics. However, variation in weapon form could also be the result of a weapon wearing out from usage. This mechanism has received relatively little attention. In this study, we demonstrate that sexually selected weapons can wear out from repeated use, providing experimental evidence that weapon usage can contribute to the diversity of weapon shapes observed within species. In a second experiment, we demonstrate that having a worn-out weapon decreases an individual's fighting ability. This finding illustrates that the shape of a weapon can have an important role in determining contest outcomes. Overall, these results suggest that individuals are limited in the number of times they can effectively use their weapons, which may be one factor (among others) influencing how frequently an animal engages in a fight.

Spatial relationships among offender, knife, and victim during slashing attacks: implications for crime scene reconstruction.

BACKGROUND: The offender-victim spatial relationship is crucial in reconstructing a crime scene. The study aims to evaluate the spatial relationship of performing slashing attacks on a dummy using a Chinese kitchen knife, and thus to establish a scientific basis for crime scene reconstruction. METHODS: Twenty-four participants (12 males and 12 females) slashed a dummy's neck or chest using a kitchen knife, and the kinematic data were obtained using a three-dimensional motion capture system. The spatial relationships among offender, knife, and victim during slashing attacks were analyzed. RESULTS: Slashing distance and occupancy area are significantly influenced by gender (all P < 0.05), with males having higher values than females. Body parts significantly influence bevel angle, offender and victim azimuth angles, slashing distance, relative slashing distance, and occupancy area (all P < 0.01), with slashing the chest resulting in larger values than slashing the neck. CONCLUSION: Gender and body position significantly influence the spatial relationships of slashing action. Our data indicate that males stand farther away and occupy a larger area during slashing attacks. When the chest is slashed, the wound orientation is more diagonal, the offender's standing position and slashing distance are farther, and the occupancy area is larger compared to the neck. The findings could help identify the spatial relationships among offender, knife, and victim, providing a scientific basis for criminal investigations and court trials.

Crossbow Injuries: Predictors of Mortality.

INTRODUCTION: Crossbow injuries are rare but carry significant morbidity and mortality, and there is limited evidence in the medical literature to guide care. This paper reviews the case reports and case series of crossbow injuries and looks for trends regarding morbidity and mortality based on the type of arrow, anatomic location of injury, and intent of injury. METHODS: Multiple databases were searched for cases of crossbow injuries and data were abstracted into a spreadsheet. Statistics were done in SPSS. RESULTS: 358 manuscripts were returned in the search. After deduplication and removal of nonclinical articles, 101 manuscripts remained. Seventy-one articles describing 90 incidents met the inclusion criteria. The mean age was 36.5 years. There were 10 female and 79 male victims. Fatality was 36% for injuries by field tip arrows and 71% for broadhead arrows, p = .024. Assaults were fatal in 84% of cases, suicides in 29%, and accidental injuries in 17%, p < .001. Mortality was similar for wounds to the head and neck (41%), chest (42%), abdomen (33%), extremities (50%), and multiple regions, p = .618. CONCLUSIONS: Crossbows are potentially lethal weapons sold with fewer restrictions than firearms. Injuries caused by broadhead arrows are more likely to be fatal than injuries from field tip arrows. The anatomic location of injury does not correlate with fatality. More than half of crossbow injuries are due to attempted suicide, with a high case-fatality rate.

Penetration performance of protective materials from crossbow attack: a preliminary study.

Crossbow-related injuries resulting in serious and mortal consequences have increased in recent years, and although significant research exists for both injury and fatality on the human body, limited data exists on the lethality of the bolt and the failure modes of protective materials. This paper concerns itself with the experimental validation of four differing crossbow bolt geometries, their effects on material failure and potentially lethality. During this study, four different types of crossbow bolt geometries were tested against two protection mechanisms that differed in mechanical properties, geometry, mass and size. The results show that at 67 ms-1, ogive, field and combo tips do not provide lethal effect at 10-m range, whilst a broadhead tip will perforate both the para-aramid and a reinforced area of polycarbonate material consisting of two 3-mm plates at 63-66 ms-1. Although perforation was apparent with a more honed tip geometry, the chain mail layering within the para-aramid protection and friction caused by polycarbonate petalling on the arrow body reduced the velocity enough to demonstrate the materials under test are effective at withstanding crossbow attack. Subsequent calculation of the maximum velocity that arrows could achieve if fired from the crossbow within this study shows results close to the overmatch value of each material and therefore a requirement to advance the knowledge in this field to influence the development of more effective armour protection mechanisms.

Gunshot residues found at the exit wound: a case report.

Gunshot residues (GSRs) play an important role in forensic investigations of gun-related violence. The presence of GSRs has been described to help to identify the bullet entry area, as it was supposed not to be found at exit wounds. This report details the suicidal headshot of an 84-year-old male where unburned tube-like, cuboid and flake-formed powder particles have been found not only at the inside of the muzzle but also circular around the exit wound. With very short-barrelled weapons, it must be expected that part of the propellant charge leaves the barrel unburned behind the bullet. In contrast to that, the barrel length of the used weapon should lead to a complete burn-up of powder particles. The surprisingly large number of unburned powder particles present at the exit wound of the injury gave reason for further investigation to understand the underlying ballistic aspects and outlines the importance of having a close look at incidence scene photos during an investigation.

A probabilistic model for murder weapon identification using stab-marks in human ribs.

The aim of this article is to provide a scientific and statistical basis to identify the murder weapon in stabbing cases from the geometric characteristics of the stab-marks left on human ribs. For this purpose, a quantitative predictive model is developed, based on geometric measurements of the stab-mark and its location along the rib. A general method based on Bayesian inference and probabilities is used for the model development, rather than a deterministic model given its inability in certain occasions to identify the murder weapon. Following the process explained in this article to collect the stab-mark information required, the complete probabilistic model exposed attained a high accuracy in the identification of the murder weapon between two macroscopically identical blades with a microscopic alteration in one of them (more than 90% of correct identification is achieved).

Injuries caused by defensive bullet launchers and resource utilization during the French yellow vests protests: A retrospective study.

BACKGROUND: In 2018, the French "Yellow Vest" social protest movement spread with weekly demonstrations resulting in confrontations between protesters and law enforcement. Non-lethal weapons, such as defensive bullet launchers (DBL) were used, and significant injuries have been reported through media, leading to public controversy regarding their use. These injuries are not well-known to civilian emergency physicians. The aim of this study is to describe the injuries caused by DBL among Emergency Department (ED) patients during these demonstrations and to identify the characteristics that required specialized care and hospital admission. METHODS: A multicenter retrospective study was conducted in 7 EDs of academic hospitals in Paris, France. Adult ED patients who presented with DBL injuries during "yellow vest" strikes between November 2018 and May 2019 were included. The primary outcome was the rate of DBL patients requiring hospital admission. We also compared the characteristics of the injuries and the care provided between the admitted patients and other DBL patients. RESULTS: 152 patients were included. 17% were admitted to hospital, with 19% of them being transferred to intensive care units. 49% of all patients had head, face, eye or neck injuries including 4 cases of intracranial hemorrhage, 1 carotide dissection, 1 laryngeal edema, 1 pneumencephalus. 11% of all patients presented with multiple wounds, and 28% had fractures (77% of admitted patients vs 18%, p < 0.001). Surgery was required for 20% of all patients (62% of admitted patients vs 10%, p < 0.001). Maxillofacial surgery was performed on 38% of admitted patients, orthopedic surgery on 25%, and neurosurgery on 13%. No death were reported. CONCLUSION: The use of DBL during the "yellow vest" civil strikes was associated with a high rate of head, face, eye or neck injuries among injured ED patients. Hospital admission was associated with a higher rate of fractures, with most of them requiring maxillofacial, orthopedic and neurosurgeries.

Impact of Implementation of a New Weapons Screening at an Urban Emergency Department.

BACKGROUND: Violence in the emergency department (ED) setting is well documented in medical literature. Weapons can be used to cause significant injury or mortality, although there is a paucity of literature on weapons and weapons screening in the ED. OBJECTIVES: The purpose of this study was to assess the impact of initiating a weapons screening process on the identification and removal of weapons. METHODS: Multiple aspects of a weapons screening program were evaluated at 2 and 6 months prior to and after a weapons screening protocol was initiated at an urban ED. In the Pre-Screen periods, only patients primarily seeking care for mental health were screened prior to entry. In the Post-Screen periods, all patients and visitors were screened with walk-through magnetometers or wand metal detectors, and additional screening checks were initiated. The number of individuals screened and numbers of weapons found were measured. Descriptive statistics comparing Pre- and Post-Screen periods were performed. RESULTS: Prior to the new screening process, 511 and 1701 patients primarily seeking care for mental health were screened, with 15 and 103 weapons confiscated at 2 and 6 months, respectively. After the screening process was initiated, 13,149 and 43,321 ED patients and visitors were screened, with 194 and 567 weapons confiscated at 2 and 6 months, respectively. Persons screened increased by 25-fold at both 2 and 6 months after implementing the screening process. Weapons confiscated increased approximately 13-fold and sixfold at the respective 2- and 6-month Pre- and Post-Screen periods, respectively. CONCLUSION: Implementation of weapons screening significantly increased the number of weapons identified and confiscated prior to entry in the ED by patients and visitors.

Death Due to Accidental Crossbow Arrow Injury: Case Report and Review of the Literature.

ABSTRACT: Crossbows are weapons that shoot arrow-like projectiles using an elastic launching mechanism activated by a gun-like trigger. Accidental deaths due to crossbow injuries have been rarely reported in forensic practice. In this case report, a 40-year-old man was found dead in the woods with a wound to the upper torso. The wound was observed to have a corresponding slit-like defect in each layer of his clothing. A blood-stained crossbow with the safety features off was found at the scene, along with a nearby partially bent arrow. At autopsy, a hemorrhagic sharp-edged penetrating track was found in the left upper chest, which injured the subclavian vessels. The mechanism of death was determined to be severe bleeding due to the penetrating wound. Toxicological analyses of blood showed methamphetamines and metabolites of cocaine. According to the available evidence, the manner of death was determined to be an accident. In crossbow-related deaths, particularly when the arrow is removed from the wound, determining the weapon used proves challenging because of the similarity of the resulting wounds to the wounds of other weapons. This case report highlights the importance of integrating critical crime scene investigation with autopsy findings to reach a correct manner of death.

[Features of coarse calico damage by hollow-point bullets of ammunitions to a 12-gauge fire smoothbore weapon (12×70) under the conditions of remote shooting distance]. / Osobennosti povrezhdeniya byazevoi tkani ekspansivnymi pulyami patronov k ognestrel'nomu gladkostvol'nomu oruzhiyu 12-go kalibra (12×70) v usloviyakh neblizkoi distantsii vystrela.

The article presents the experimental study results of damaged clothes imitators' (coarse calico) features in consequence of shot by ammunitions with hollow-point bullet from a 12-gauge fire smoothbore weapon (12×70). The generation mechanism of coarse calico damage during wound of underlying biological human body's imitator by bullet and the factors influencing on mentioned process have been clarified using high-speed video recording.

[Impact of projectile incidence angle with obstacle during ricochet on the damage characteristics formed in smoothbore weapon shot]. / Vliyanie ugla vstrechi puli s pregradoi pri rikoshete na kharakteristiku povrezhdenii, obrazuyushchikhsya pri vystrele iz gladkostvol'nogo oruzhiya.

The aim of this study was to establish the degree of projectile incidence angle with obstacle on forensic medical characteristic of gunshot injuries arising from smoothbore weapon fire and bullet ricochet. Based on the comprehensive forensic study results of experimental entry gunshot injuries, statistically significant differences in the following morphological signs were found for two ranges of incidence angle values (10-20° and 30-50°): «Number of MD¼, «Length 1 MD¼, «Length 2 MD¼, «Width 1 MD¼, «Orientation of AD to the conventional clock face relative to MD 1 or to the group of largest MD (max. value)¼. The medians and limits of 99% confidence intervals of these features values were observed depending on the range of incidence angle values. The revealed patterns can be used in expert practice during forensic medical examination of gunshot injuries formed as a result of a projectile ricochet after smoothbore weapon fire, as well as to develop a methodology for conducting a forensic study of this gunshot injury type.

Measuring dimensional and morphological heat alterations of dismemberment-related toolmarks with an optical roughness metre.

This experimental study provides a further understanding of the post-burning nature of sharp force trauma. The main objective is to analyse the distortion that fire may inflict on the length, width, roughness, and floor shape morphology of toolmarks induced by four different implements. To this end, four fresh juvenile pig long bones were cut with a bread knife, a serrated knife, a butcher machete, and a saw. A total of 120 toolmarks were induced and the bone samples were thus burnt in a chamber furnace. The lesions were analysed with a 3D optical surface roughness metre before and after the burning process. Afterwards, descriptive statistics and correlation tests (Student's t-test and analysis of variance) were performed. The results show that fire exposure can distort the signatures of sharp force trauma, but they remain recognisable and identifiable. The length decreased in size and the roughness increased in a consistent manner. The width did not vary for the saw, serrated knife, or machete toolmarks, while the bread knife lesions slightly shrunk. The floor shape morphology varied after burning, and this change became more noticeable for the three knives. It was also observed that the metrics of the serrated knife and machete cut marks showed no significant variations. Our results demonstrate that there is a variation in the toolmark characteristics after burning. This distortion is dependent on multiple factors that influence their dimensional and morphological changes, and the preservation of class features is directly reliant upon the weapon employed, the trauma caused, and the burning process conditions.

Application of 3D printing in assessment and demonstration of stab injuries.

In stabbing related fatalities, the forensic pathologist has to assess the direction of wound track (thus, the direction of the stabbing) and the weapon's possible characteristics by examining the stab wound. The determination of these characteristics can be made only with a high level of uncertainty, and the precise direction of the stabbing is often difficult to assess if only soft tissues are injured. Previously reported techniques used for the assessment of these wound characteristics have substantial limitations. This manuscript presents a method using today's easily accessible three-dimensional (3D) printing technology for blade-wound comparison and wound track determination. Scanning and 3D printing of knives is a useful method to identify weapons and determine the precise stabbing direction in a stabbing incident without compromising the trace evidence or the autopsy results. Ballistic gel experiment, and dynamic stabbing test experiments prove the method can be applied in safety, without compromising the autopsy results. Identification of the exact knife is not possible with complete certainty but excluding certain knives will decrease the number of necessary DNA examinations, hence it can lower the burden on forensic genetic laboratories. The method addresses many of the shortcomings of previously used methods of probe insertion or post-mortem CT. Insertion of the printed knife into the wound gives a good visual demonstration of the stabbing direction, thus easing the forensic reconstruction of the stabbing incident. After combining the 3D printing with photogrammetry, the achieved 3D visualization is useful for courtroom demonstration and educational purposes.

A Case of Fatal Exsanguination by a Japanese Short Sword.

ABSTRACT: We report a rare case of fatal exsanguination by a wakizashi , a Japanese short sword ( shinken ). A man in his 60s was found lying on his back on his bed. He was in cardiopulmonary arrest when the ambulance crew arrived and was pronounced dead on arrival at the hospital. A wakizashi with blood stains on the blade was found on the floor, and blood was present on the bed sheets on which the man was found. Autopsy revealed an incised wound extending diagonally from superolaterally to inferomedially on the anterior left thigh as the only injury. The wound appeared mostly straight, approximately 44 cm long and 9 cm deep, with smooth walls. The left femoral artery and vein had been cleanly severed, and the cause of death was determined to be blood loss from the severed blood vessels. The wakizashi (blade length, 45 cm) was large enough to have caused the wound, and the left thigh was presumed to have been incised by a downward slash from the sword.

Implementation of and Experimentation with Ground-Penetrating Radar for Real-Time Automatic Detection of Buried Improvised Explosive Devices.

This paper proposes the implementation of and experimentation with GPR for real-time automatic detection of buried IEDs. GPR, consisting of hardware and software, was implemented. A UWB antenna was designed and implemented, particularly for the operation of the GPR. The experiments were conducted in order to demonstrate the real-time automatic detection of buried IEDs using GPR with an R-CNN algorithm. In the experiments, the GPR was mounted on a pickup truck and a maintenance train in order to find the IEDs buried under a road and a railway, respectively. B-scan images were collected using the implemented GPR. R-CNN-based detection for the hyperbolic pattern, which indicates the buried IED, was performed along with pre-processing, for example, using zero offset removal, and background removal and filtering. Experimental results in terms of detecting the hyperbolic pattern in B-scan images were shown and verified that the proposed GPR system is superior to the conventional one using region analysis processing-based detection. Results also showed that pre-processing is required in order to improve and/or clean the hyperbolic pattern before detection. The GPR can automatically detect IEDs buried under roads and railways in real time by detecting the hyperbolic pattern appearing in the collected B-scan image.

The Effect of Tactical Tasks and Gear on Muscle Activation of SWAT Officers.

ABSTRACT: Keeler, JM, Pohl, MB, Bergstrom, HC, Thomas, JM, and Abel, MG. The effect of tactical tasks and gear on muscle activation of SWAT officers. J Strength Cond Res 36(1): 238-244, 2022-Special Weapons and Tactics (SWAT) officers perform a variety of tactical operations while wearing tactical gear. Load carriage has been shown to alter muscle activation in the torso and is also associated with lower back pain, which is a prevalent musculoskeletal injury suffered by SWAT Officers. The purpose of this study was to quantify the effect of tactical gear on muscle activation of torso musculature while performing occupational tasks. Twenty male SWAT Officers (age: 34.7 ± 4.5 years; height: 1.79 ± 0.1 m; body mass: 91.5 ± 17.3 kg) performed 4 tasks (standing, rifle walk, sitting, and shield walk) with and without gear (mass of gear: 13.8 ± 1.9 kg). Mean electromyographic amplitude was evaluated bilaterally for the erector spinae, rectus abdominis, and external oblique muscles during the trials and expressed relative to maximal voluntary isometric contraction (MVIC). Addition of gear significantly increased erector spinae mean muscle activation during the rifle walk task (mean delta: +0.16%). However, no differences in muscle activation were identified for any other muscles between gear conditions (effect size ≤ 0.15). The shield walk produced the highest mean activation for each muscle during different tasks. The dynamic tasks yielded (0.24-4.18% MVIC) greater muscle activation levels than sitting and standing tasks. Despite minimal increases in muscle activation levels with the addition of gear, load carriage is known to increase the risk of acute and chronic injury. Collectively, these findings indicate that SWAT Officers should perform most skills without gear during tactical training to simulate task-specific movement patterns but reduce the risk of musculoskeletal injury.