SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Missile

59

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

33

How does one prove a claim about a highly sensitive object such as a nuclear weapon without revealing information about the object? This paradox has challenged nuclear arms control for more than five decades. We present a mechanism in the form of an interactive proof system that can validate the structure and composition of an object, such as a nuclear warhead, to arbitrary precision without revealing either its structure or composition. We introduce a tomographic method that simultaneously resolves both the geometric and isotopic makeup of an object. We also introduce a method of protecting information using a provably secure cryptographic hash that does not rely on electronics or software. These techniques, when combined with a suitable protocol, constitute an interactive proof system that could reject hoax items and clear authentic warheads with excellent sensitivity in reasonably short measurement times.

Concepts: Nuclear weapon, Cryptography, Missile

24

Nuclear disarmament treaties are not sufficient in and of themselves to neutralize the existential threat of the nuclear weapons. Technologies are necessary for verifying the authenticity of the nuclear warheads undergoing dismantlement before counting them toward a treaty partner’s obligation. Here we present a concept that leverages isotope-specific nuclear resonance phenomena to authenticate a warhead’s fissile components by comparing them to a previously authenticated template. All information is encrypted in the physical domain in a manner that amounts to a physical zero-knowledge proof system. Using Monte Carlo simulations, the system is shown to reveal no isotopic or geometric information about the weapon, while readily detecting hoaxing attempts. This nuclear technique can dramatically increase the reach and trustworthiness of future nuclear disarmament treaties.

Concepts: Nuclear fission, United Nations, Nuclear weapon, Nuclear proliferation, Nuclear warfare, Cryptography, Missile, Nuclear disarmament

4

Zero-knowledge proofs are mathematical cryptographic methods to demonstrate the validity of a claim while providing no further information beyond the claim itself. The possibility of using such proofs to process classified and other sensitive physical data has attracted attention, especially in the field of nuclear arms control. Here we demonstrate a non-electronic fast neutron differential radiography technique using superheated emulsion detectors that can confirm that two objects are identical without revealing their geometry or composition. Such a technique could form the basis of a verification system that could confirm the authenticity of nuclear weapons without sharing any secret design information. More broadly, by demonstrating a physical zero-knowledge proof that can compare physical properties of objects, this experiment opens the door to developing other such secure proof-systems for other applications.

Concepts: Mathematics, Neutron, Nuclear fusion, Nuclear fission, Nuclear weapon, Nuclear proliferation, Cryptography, Missile

3

Future nuclear arms reduction efforts will require technologies to verify that warheads slated for dismantlement are authentic without revealing any sensitive weapons design information to international inspectors. Despite several decades of research, no technology has met these requirements simultaneously. Recent work by Kemp et al. [Kemp RS, Danagoulian A, Macdonald RR, Vavrek JR (2016) Proc Natl Acad Sci USA 113:8618-8623] has produced a novel physical cryptographic verification protocol that approaches this treaty verification problem by exploiting the isotope-specific nature of nuclear resonance fluorescence (NRF) measurements to verify the authenticity of a warhead. To protect sensitive information, the NRF signal from the warhead is convolved with that of an encryption foil that contains key warhead isotopes in amounts unknown to the inspector. The convolved spectrum from a candidate warhead is statistically compared against that from an authenticated template warhead to determine whether the candidate itself is authentic. Here we report on recent proof-of-concept warhead verification experiments conducted at the Massachusetts Institute of Technology. Using high-purity germanium (HPGe) detectors, we measured NRF spectra from the interrogation of proxy “genuine” and “hoax” objects by a 2.52 MeV endpoint bremsstrahlung beam. The observed differences in NRF intensities near 2.2 MeV indicate that the physical cryptographic protocol can distinguish between proxy genuine and hoax objects with high confidence in realistic measurement times.

Concepts: Measurement, Nuclear fission, Nuclear weapon, Cold War, Formal verification, Missile, Nuclear weapon design, Inspector Clouseau

0

This article presents both a fatal suicide incident by Flobert 9 mm-type smoothbore weapon with a single-shot projectile and a nonfatal case of a suicide attempt by the same weapon type with a dispersion cartridge from the authors' forensic record. A retrospective study was conducted examining 84 cases involving cases of headshots inflicted by all kinds of weapons deriving from the broader region of Eastern Macedonia and Thrace (Northern Greece) between 2000 and 2015, among which only 1 involved lethal wounding by a Flobert 9 mm (1.19%). Only a single case report of a fatality with such a weapon has been described throughout international literature. A comparative study also follows between the 3 incidents. The authors argue that a prerequisite for the lethal outcome of the shooting is the absolute contact of the weapon to the head as well as its placement at an anatomical point where the bone resistance is relatively lower, so that the intracranial entry of the projectile is possible. It is also more harmful if the cartridge contains a single-shot projectile rather than multiple projectiles of smaller diameter.

Concepts: Projectile, Firearm, Ammunition, Western Thrace, Weapon, Gun, Missile, East Macedonia and Thrace

0

In this issue of Cancer Cell, Seaman et al. demonstrate that antibody drug conjugates (ADCs) against CD276 expressed by tumor cells and tumor vasculature have promising anti-tumor activity while showing little toxicity. Importantly, these agents have the potential to target both angiogenic vessels and non-angiogenic vessels co-opted by tumor cells.

Concepts: Gene expression, Cancer, Oncology, Cell division, Benign tumor, Tumor, Neoplasm, Missile

0

Recent research proposes that left hemispheric lateralization (HL) may protect against the effects of life events on mental distress. This study extends these findings by examining the protective role of left-HL in the relationship between war threat (missile exposure) and PTSD symptoms. A sample of 186 Israelis, exposed to missile attacks, completed brief scales of self-reported missile exposure, a subjective and a neuropsychological HL measure, and of PTSD symptoms. The sample was split into right-HL and left-HL individuals on both HL measures. Self-reported missile exposure was positively associated with PTSD symptoms in right-HL, but not in left- HL individuals on both HL measures. These results replicate and extend our previous results and suggest that left-HL may even protect against the effects of severe life threatening events. Results are discussed in relation to neuropsychological and neurophysiological differences between the hemispheres.

Concepts: Life, Neuropsychology, Protection, Exposure, PTSD, Lateralization of brain function, Missile

0

This paper presents the results of experimental investigations of a precision sensor for an automatic weapons stabilizer system. It also describes the experimental equipment used and the structure of the developed sensor. A weapons stabilizer is designed for automatic guidance of an armament unit in the horizontal and vertical planes when firing at ground and air targets that are quickly maneuvering, and at lower speeds when firing anti-tank missiles, as well as the bypass of construction elements by the armament unit, and the automatic tracking of moving targets when interacting with a fire control system. The results of experimental investigations have shown that the error of the precision sensor developed on the basis of a piezoelectric element is 6 × 10(-10) m/s² under quasi-static conditions, and ~10(-5) m/s² for mobile use. This paper defines metrological and calibration properties of the developed sensor.

Concepts: Measurement, Metrology, Test method, Ammunition, Dimensional analysis, Weapon, Missile, Infantry

0

Pursuant to the Polish Weapons and Ammunitions Law, muzzle-loading black powder weapons, manufactured before 1885, or their replicas, as well as suitable projectiles, can be possessed legally without registration and special licenses. The aim of the study was to assess the penetration depth of projectiles fired from a black powder weapon, replica of Colt Navy of 1851, in 20% gelatin blocks and to compare the obtained results with the actual injuries found on autopsy of a 78-year-old man who had committed suicide. In the experiments, we used the black powder weapon and ammunitions, as well as gelatin blocks serving as a soft tissue model. We ascertained that solid spherical projectiles fired from black powder weapons cause extensive injuries, especially in the initial segment of the wound canal. Additionally, based on the presence and location of the wad in the wound canal, the distance from which the shot was fired can be determined.

Concepts: Projectile, Ammunition, Weapon, Gun, Death metal, Missile, Small arms, Colt 1851 Navy Revolver