Arming the Outlaws: On the Moral Limits of the Arms Trade

There is a general presumption against arming outlaw states. But can that presumption sometimes be overturned? The argument considered here maintains that outlaw states can have legitimate security interests, and that transferring weapons to these states can be an appropriate way of promoting those interests. Weapons enable governments to engage in wrongful oppression and aggression, but they also enable them to fend off predators in a manner that can be beneficial to their citizens. It clearly does not follow from the fact that a state is oppressive or aggressive that it will never be a victim of wrongful aggression itself, and while an outlaw state’s primary aim in repelling such aggression will often be the preservation of its own power, its defensive manoeuvres will sometimes also serve its citizens’ interests. In short, supplying weapons to outlaw states may sometimes contribute to the protection of innocents

Nuclear Transparency to Intermediate-Energy Protons

Nuclear transparency in the (e,e'p) reaction for 135 < Tp < 800 MeV is investigated using the distorted wave approximation. Calculations using density-dependent effective interactions are compared with phenomenological optical potentials. Nuclear transparency is well correlated with proton absorption and neutron total cross sections. For Tp < 300 MeV there is considerable sensitivity to the choice of optical model, with the empirical effective interaction providing the best agreement with transparency data. For Tp > 300 MeV there is much less difference between optical models, but the calculations substantially underpredict transparency data and the discrepancy increases with A. The differences between Glauber and optical model calculations are related to their respective definitions of the semi-inclusive cross section. By using a more inclusive summation over final states the Glauber model emphasizes nucleon-nucleon inelasticity, whereas with a more restrictive summation the optical model emphasizes nucleon-nucleus inelasticity; experimental definitions of the semi-inclusive cross section lie between these extremes.Comment: uuencoded gz-compressed tar file containing revtex and bbl files and 5 postscript figures, totalling 31 pages. Uses psfi

Acceleration of relativistic beams using laser-generated terahertz pulses

Dielectric structures driven by laser-generated terahertz (THz) pulses may hold the key to overcoming the technological limitations of conventional particle accelerators and with recent experimental demonstrations of acceleration, compression and streaking of low-energy (sub-100 keV) electron beams, operation at relativistic beam energies is now essential to realize the full potential of THz-driven structures. We present the first THz-driven linear acceleration of relativistic 35 MeV electron bunches, exploiting the collinear excitation of a dielectric-lined waveguide driven by the longitudinal electric field component of polarization-tailored, narrowband THz pulses. Our results pave the way to unprecedented control over relativistic electron beams, providing bunch compression for ultrafast electron diffraction, energy manipulation for bunch diagnostics, and ultimately delivering high-field gradients for compact THz-driven particle acceleration.Comment: 8 pages, 4 figure

Quantitative assessment of the conjunctival microcirculation using a smartphone and slit-lamp biomicroscope

Purpose: The conjunctival microcirculation is a readily-accessible vascular bed for quantitative haemodynamic assessment and has been studied previously using a digital charge-coupled device (CCD). Smartphone video imaging of the conjunctiva, and haemodynamic parameter quantification, represents a novel approach. We report the feasibility of smartphone video acquisition and subsequent haemodynamic measure quantification via semi-automated means. Methods: Using an Apple iPhone 6 s and a Topcon SL-D4 slit-lamp biomicroscope, we obtained videos of the conjunctival microcirculation in 4 fields of view per patient, for 17 low cardiovascular risk patients. After image registration and processing, we quantified the diameter, mean axial velocity, mean blood volume flow, and wall shear rate for each vessel studied. Vessels were grouped into quartiles based on their diameter i.e. group 1 (&lt;11 μm), 2 (11–16 μm), 3 (16–22 μm) and 4 (&gt;22 μm). Results: From the 17 healthy controls (mean QRISK3 6.6%), we obtained quantifiable haemodynamics from 626 vessel segments. The mean diameter of microvessels, across all sites, was 21.1μm (range 5.8–58 μm). Mean axial velocity was 0.50mm/s (range 0.11–1mm/s) and there was a modestly positive correlation (r 0.322) seen with increasing diameter, best appreciated when comparing group 4 to the remaining groups (p &lt; .0001). Blood volume flow (mean 145.61pl/s, range 7.05–1178.81pl/s) was strongly correlated with increasing diameter (r 0.943, p &lt; .0001) and wall shear rate (mean 157.31 s − 1, range 37.37–841.66 s − 1) negatively correlated with increasing diameter (r − 0.703, p &lt; .0001). Conclusions: We, for the first time, report the successful assessment and quantification of the conjunctival microcirculatory haemodynamics using a smartphone-based system. </p

A Simple HEPA Filtering Facepiece

Shortages of efficient filtering facepiece respirators leave the public vulnerable to transmission of infectious diseases in small particle aerosols. This study demonstrates that a high-filtration-efficiency facepiece capable of filtering out >95% of 0.05μm particles while being worn can be simply produced with available materials