Wounding patterns and human performance in knife attacks: optimising the protection provided by knife-resistant body armour

Stab attacks generate high loads,1 and to defeat them, armour needs to be of a certain thickness and stiffness.2,3 Slash attacks produce much lower loads and armour designed to defeat them can be far lighter and more flexible.Methods and subjects: Phase 1: Human performance in slash attacks: 87 randomly selected students at the Royal Military College of Science were asked to make one slash attack with an instrumented blade on a vertically mounted target. No instructions on how to slash the target were given. The direction, contact forces and velocity of each attack were recorded. Phase 2: Clinical experience with edged weapon attacks: The location and severity of all penetrating injuries in patients attending the Glasgow Royal Infirmary between 1993 and 1996 were charted on anatomical figures.Results Phase 1: Two types of human slash behaviour were evident: a ‘chop and drag’ blow and a ‘sweep motion’ type of attack. ‘Chop and drag’ attacks had higher peak forces and velocities than sweep attacks. Shoulder to waist blows (diagonal) accounted for 82% of attacks, 71% of attackers used a long diagonal slash with an average cut length of 34 cm and 11% used short diagonal attacks with an average cut length of 25 cm. Only 18% of attackers slashed across the body (short horizontal); the average measured cut length of this type was 28 cm. The maximum peak force for the total sample population was 212 N; the maximum velocity was 14.88 m s−1. The 95 percentile force for the total sample population was 181 N and the velocity was 9.89 m s−1. Phase 2: 431 of the 500 patients had been wounded with edged weapons. The average number of wounds sustained by victims in knife assaults was 2.4. The distribution of wounds by frequency and severity are presented.Conclusions Anti-slash protection is required for the arms, neck, shoulders, and thighs. The clinical experience of knife-attack victims provides information on the relative vulnerabilities of different regions of the body. It is anticipated that designing a tunic-type of Police uniform that is inherently stab and slash resistant will eventually replace the current obvious and often bulky extra protective vest. Attempts at making a combined garment will need to be guided by ergonomic considerations and field testing. A similar anatomical regional risk model might also be appropriate in the design of anti-ballistic armour and combined anti-ballistic and knife-resistant armour

Blade Sharpness and its Effect on the Testing of Body Armours

Factors such as edge sharpness and tip sharpness have been identified by Horsfall,1 as keyvariables in the testing of stab and slash resistant armours. This paper evaluates the influenceof blade sharpness on the mechanics of penetration and its relationship with a variety ofmaterials used for body armour systems. The differences in performance between blunt andsharp blades are compared by dynamic tests using an instrumented drop tower, measuringpeak loads and energy to penetration. Variance in the initial impact forces required topenetrate body armour between blunt and sharp blades is shown. However, the total energyto penetration for both sharp and blunt knives was found to be similar for a specific bodyarmour system. Dynamic tests were also used to evaluate the effect of wear on bladeperformance by the comparison of the initial loads for puncture and depth of penetration onaramid and metallic armour systems. The effect of sharpness on the reproducibility of testresults is also investigated and discussed. Various test methods are described for themeasurement of sharpness for both stab and slash and compared. The recent development ofa new non-destructive proof test method to measure tip and edge sharpness is also described

Painted Plaster Reproduction of a Minoan Marine-style Terracotta Vase from Egypt

1925-26 Marine style, as shown in this piece, is a common style of Minoan pottery. It is characterized by detailed and naturalistic depictions of marine life,1 in this piece coral, sponges, and seaweed. Minoan culture was centered on the island of Crete and therefore depictions of the sea and assorted creatures and plants found within it would have been a way of depicting the world around them. In this piece, the style is more direct and literal with little to no variation from observational depictions. Later pieces done in Marine style, such as the famous Octopus flask, show a more stylized method of depicting marine life with aspects of the creatures or plants becoming designs inspired by their real life shapes. Hints of this can be seen on the neck and handle of the vase where fluid lines are shown to continue the theme of plant life. With regards to this particular piece, the style is emphasized by the anthropomorphic shape of the vase. The way in which the curves of the body of the vase and the handle mirror the curves of the marine life. This creates a harmony between the content and form of the piece2 as well as furthers the naturalistic and descriptive quality of the work by creating a true sense of being underwater with the forms moving with the currents. The piece presents as fluid and cohesive. This particular piece is a reproduction, created by Scandinavian artist Halvor Bagge, of a Minoan vase found in Egypt in 1893.3 The reproduction is made from painted plaster whereas the original would have been terracotta.4 The original is owned by the Borély Museum in Marseilles while the reproduction is owned by the Metropolitan Museum of Art in New York City. The advantage of having a reproduction is that it allows easier access for the general public to see the work, without having to travel out of the country or around the world. It also allows the museum to present a more complete and comprehensive collection of art from the period without needing to buy or borrow the original piece. This does bring up questions though of whether or not the same experience can be gained from seeing a reproduction of a piece compared to the original. It is worth traveling to see the reproduction when you could simply view an image of the original from your computer screen at home? The line between forgeries and reproductions can also be blurred here as many artists have created reproductions of original pieces and sold them for their own personal profit.5 Overall though, if presented as a reproduction the addition to a collection can be both beneficial to the museum and to the viewer as a way of gaining a larger perspective on the culture or time period as a whole. Bibliography Archino, Sarah, Dr. Minoan Art. Lecture, Art 230 ­ Ancient Art I, Greenville, October, 2015. Cartwright, Mark. Minoan Pottery. Ancient History Encyclopedia. May 30, 2012. Accessed November 1, 2015. http://www.ancient.eu/article/391/. Hemingway, Sean. Historic Images of the Greek Bronze Age. Historic Images of the Greek Bronze Age. May 17, 2011. Accessed November 1, 2015.https://scholarexchange.furman.edu/art231/1073/thumbnail.jp

Metabolic regulation by p53 family members

The function of p53 is best understood in response to genotoxic stress, but increasing evidence suggests that p53 also plays a key role in the regulation of metabolic homeostasis. p53 and its family members directly influence various metabolic pathways, enabling cells to respond to metabolic stress. These functions are likely to be important for restraining the development of cancer but could also have a profound effect on the development of metabolic diseases, including diabetes. A better understanding of the metabolic functions of p53 family members may aid in the identification of therapeutic targets and reveal novel uses for p53-modulating drugs

Short-time dynamics of finite-size mean-field systems

We study the short-time dynamics of a mean-field model with non-conserved order parameter (Curie-Weiss with Glauber dynamics) by solving the associated Fokker-Planck equation. We obtain closed-form expressions for the first moments of the order parameter, near to both the critical and spinodal points, starting from different initial conditions. This allows us to confirm the validity of the short-time dynamical scaling hypothesis in both cases. Although the procedure is illustrated for a particular mean-field model, our results can be straightforwardly extended to generic models with a single order parameter.Comment: accepted for publication in JSTA

Surface states on a topologically non-trivial semimetal: The case of Sb(110)

The electronic structure of Sb(110) is studied by angle-resolved photoemission spectroscopy and first-principle calculations, revealing several electronic surface states in the projected bulk band gaps around the Fermi energy. The dispersion of the states can be interpreted in terms of a strong spin-orbit splitting. The bulk band structure of Sb has the characteristics of a strong topological insulator with a Z2 invariant nu0=1. This puts constraints on the existence of metallic surface states and the expected topology of the surface Fermi contour. However, bulk Sb is a semimetal, not an insulator and these constraints are therefore partly relaxed. This relation of bulk topology and expected surface state dispersion for semimetals is discussed.Comment: 7 pages, 4 figure