Association of traumatic brain injury with intentional and unintentional injury among United States Operation Enduring Freedom, Operation Iraqi Freedom and Operation New Dawn veterans

Traumatic brain injury (TBI) is considered the “signature injury” for United States Veterans who deployed in support of Operation Enduring Freedom (OEF), Operation Iraqi Freedom (OIF), and Operation New Dawn (OND) since 2001. Veterans with TBI may be at higher risk for subsequent intentional and unintentional injuries due to cognitive and executive function impairments from the injury and co-occurring psychiatric conditions. This dissertation evaluated the association between TBI and attempted suicide, motor vehicle accidents, and opioid overdose, in a large cohort of United States OEF/OIF/OND Veterans aged 18 to 40 who received care in the Veterans Health Administration (VHA). These studies utilized data from the VHA electronic medical records collected between April 2007 and September 2012. Study 1 evaluated the association between TBI and attempted suicide. Veterans with TBI had approximately a 4-fold increased risk of attempted suicide compared to those without, adjusting for demographics (adjusted hazard ratio (aHR): 3.73, 95% CI = 3.07, 4.53). The mediation analyses suggested that the psychiatric conditions substantially attenuated the impact of TBI on attempted suicide (aHR: 1.25 (95% CI = 1.05, 1.48). Study 2 evaluated the association between TBI and motor vehicle accidents. Veterans with TBI had a 56% increased risk of motor vehicle accident compared to those without, adjusting for demographics (aHR: 1.58, 95% CI = 1.27, 1.97). However, the mediation analyses attenuated this association (aHR: 1.17, 95% CI = 0.96, 1.43). Study 3 evaluated the association between TBI and opioid overdose among OEF/OIF/OND Veterans receiving long-term opioid treatment for non-cancer, chronic pain. Veterans with TBI had 2-fold increased risk for opioid overdose compared to those without, adjusting for demographics (aHR: 2.00, 95% CI = 1.26, 3.16). Nevertheless, the mediation analyses suggested that psychiatric conditions attenuated the impact of TBI on opioid overdose (aHR: 1.38, 95% CI = 0.94, 2.01). In conclusion, these studies add to the literature about risk of intentional and unintentional injuries among Veterans with TBI. Additionally, it highlights that Veterans with TBI and at least one co-morbid psychiatric condition are a particularly vulnerable group with the highest risk for injuries

Universal Local symmetries and non-superposition in classical mechanics

In the Hilbert space formulation of classical mechanics (CM), pioneered by Koopman and von Neumann (KvN), there are potentially more observables that in the standard approach to CM. In this paper we show that actually many of those extra observables are not invariant under a set of universal local symmetries which appear once the KvN is extended to include the evolution of differential forms. Because of their non-invariance, those extra observables have to be removed. This removal makes the superposition of states in KvN, and as a consequence also in CM, impossible

On the decay law for unstable open systems

We use (nonconservative) dynamical semigroups to investigate the decay law of a quantum unstable system weakly coupled with a large environment. We find that the deviations from the classical exponential law are small and can be safely ignored in any actual experiment.Comment: 12 pages, plain-TeX, to appear in Phys. Lett.

An Integrated XRF/XRD Instrument for Mars Exobiology and Geology Experiments

By employing an integrated x-ray instrument on a future Mars mission, data obtained will greatly augment those returned by Viking; details characterizing the past and present environment on Mars and those relevant to the possibility of the origin and evolution of life will be acquired. A combined x-ray fluorescence/x-ray diffraction (XRF/XRD) instrument was breadboarded and demonstrated to accommodate important exobiology and geology experiment objectives outlined for MESUR and future Mars missions. Among others, primary objectives for the exploration of Mars include the intense study of local areas on Mars to establish the chemical, mineralogical, and petrological character of different components of the surface material; to determine the distribution, abundance, and sources and sinks of volatile materials, including an assessment of the biologic potential, now and during past epoches; and to establish the global chemical and physical characteristics of the Martian surface. The XRF/XRD breadboard instrument identifies and quantifies soil surface elemental, mineralogical, and petrological characteristics and acquires data necessary to address questions on volatile abundance and distribution. Additionally, the breadboard is able to characterize the biogenic element constituents of soil samples providing information on the biologic potential of the Mars environment. Preliminary breadboard experiments confirmed the fundamental instrument design approach and measurement performance

Quantum dynamics and statistics of two coupled down-conversion processes

In the framework of Heisenberg-Langevin theory the dynamical and statistical effects arising from the linear interaction of two nondegenerate down-conversion processes are investigated. Using the strong-pumping approximation the analytical solution of equations of motion is calculated. The phenomena reminiscent of Zeno and anti-Zeno effects are examined. The possibility of phase-controlled and mismatch-controlled switching is illustrated.Comment: 17 pages, 7 figure

Complete positivity and correlated neutral kaons

In relation with experiments on correlated kaons at phi-factories, it is shown that the request of complete positivity is necessary in any physically consistent description of neutral kaons as open quantum systems.Comment: LaTeX, 9 page

No classical limit of quantum decay for broad states

Though the classical treatment of spontaneous decay leads to an exponential decay law, it is well known that this is an approximation of the quantum mechanical result which is a non-exponential at very small and large times for narrow states. The non exponential nature at large times is however hard to establish from experiments. A method to recover the time evolution of unstable states from a parametrization of the amplitude fitted to data is presented. We apply the method to a realistic example of a very broad state, the sigma meson and reveal that an exponential decay is not a valid approximation at any time for this state. This example derived from experiment, shows the unique nature of broad resonances

Dissipative effects in semileptonic B decays

We study the time evolution and decay of the neutral B-meson system using quantum dynamical semigroups. New, nonstandard terms appear in the expression of relevant observables; they can be parametrized in terms of six phenomenological constants. Although very small, these parameters may be detected in the new generation of dedicated B-meson experiments.Comment: 14 pages, plain-Te

Galilean non-invariance of geometric phase

It is shown that geometric phase in non-relativistic quantum mechanics is not Galilean invariant.Comment: LaTeX, 6 pages, no figure