415 research outputs found
Spoofed Networks: Exploitation of GNSS Security Vulnerability in 4G and 5G Mobile Networks
Includes supplementary materialFifth Generation New Radio (5G NR) represents a shift in mobile telephony whereby the network architecture runs containerized software on commodity hardware. In preparation for this transition, numerous 4G Long Term Evolution software stacks have been developed to test the containerization of core network functions and the interfaces with radio access network protocols. In this thesis, one such stack, developed by the OpenAirInterface Software Alliance, was used to create a low-cost, simplified mobile network compatible with the Naval Operational Architecture. Commercial off-the-shelf user equipment was then connected to the network to demonstrate how a buffer overflow vulnerability found in Qualcomm Global Navigation Satellite System chipsets and identified as CVE-2019-2254 can be leveraged to enable a spoofed network attack. The research also yielded an extension of the attack method to 5G NR networks.http://archive.org/details/aplaceholderreco1094567451Lieutenant, United States NavyApproved for public release. Distribution is unlimited
The Effect of Test Cell Glass Cylinder Diameter on Gaseous Insulation Dielectric Strength
Areas of Investigation 1. To determine the effect of test cell glass cylinder diameter on gaseous insulation dielectric strength for uniform and non-uniform fields through experimental results and field plots. 2. To obtain an upper limit for gap spacing in different size test cells for uniform and non-uniform fields. 3. To determine the effect of frequent change of gas in cell during test. 4. To determine extraneous effects, such as cell clamps. 5. To suggest the size in which a test cell should be to obtain good results in gaseous insulation dielectric strength tests. These areas will be investigated by the author through the highest attainable accuracy that can be achieved with the precision of the test equipment available
Evaluating Yield Models for Crop Insurance Rating
Generated crop insurance rates depend critically on the distributional assumptions of the underlying crop yield loss model. Using farm level corn yield data from 1972-2008, we revisit the problem of examining in-sample goodness-of-fit measures across a set of flexible parametric, semi-parametric, and non-parametric distributions. Simulations are also conducted to investigate the out-of-sample efficiency properties of several competing distributions. The results indicate that more parameterized distributional forms fit the data better in-sample due to the fact that they have more parameters, but are generally less efficient out-of-sample–and in some cases more biased–than more parsimonious forms which also fit the data adequately, such as the Weibull. The results highlight the relative advantages of alternative distributions in terms of the bias-efficiency tradeoff in both in- and out-of-sample frameworks.Yield distributions, Crop Insurance, Weibull Distribution, Beta Distribution, Mixture Distribution, Out-of-Sample Efficiency, Goodness-of-Fit, Insurance Rating Efficiency, Farm Management, Financial Economics, Land Economics/Use,
Determinants of Successful Weight Loss in Low-Income African American Women: A Positive Deviance Analysis.
OBJECTIVE: We set out to investigate the behaviors of low-income African American women who successfully lost weight.
METHODS: From an urban, academic, family medicine practice, we used a mixed methods positive deviance approach to evaluate 35 low-income African American women who were obese and lost at least 10% of their maximum weight, and maintained this loss for 6 months, comparing them with 36 demographically similar control participants who had not lost weight. Survey outcomes included demographics and behaviors that were hypothesized to be related to successful weight loss. Interviews focused on motivations, barriers, and what made weight loss successful. Survey data were analyzed using t tests and linear regression for continuous outcomes and chi-square tests and logistic regression for categorical outcomes. Interviews were analyzed using a modified approach to grounded theory.
RESULTS: In adjusted analyses, women in the positive deviant group were more likely to be making diet changes compared with those women who did not lose at least 10% of their initial body weight. Major themes from qualitative analyses included ( a) motivations (of health, appearance, quality of life, family, and epiphanies), ( b) opportunity (including time and support), ( c) adaptability.
CONCLUSIONS: The findings of this study may be useful in developing motivational interviewing strategies for primary care providers working with similar high-risk populations
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Radiographic techniques in the Explosive Component Facility at Sandia National Labs
ECF is a state of the art facility for design and testing of energetic materials and components. Two key elements are the flash x-ray machines: a 6-head 150 keV, and a 6-head 300-keV instrument. The 150 keV system was used to study the action and reaction of a linear shaped charge (LSC) while submerged in water; the submerged samples were viewed from the top to capture the interaction of one piece with another piece nearby. Each LSC was covered by separate rubber coverings and affixed to a composite plate. Three heads, delayed by a specified time, were used to capture the time sequence. Side views were done with and without the rubber coverings to examine the dampening effect of the cover. An end-on perspective was also captured by x-ray using one head and several time delays. Debris scatter from a larger device was also examined. Explosive used was in a pellet form initiated by a detonator and a timing lead. The x-ray radiographs show the particles from this device as they expand outward. Three x-ray source tubes were used in a large horizontal array, apertured to expose individual pieces of film. Another x-ray source was placed overhead and simultaneously exposed a film under the object
Pseudomonas fluorescens CHA0 maintains carbon delivery to Fusarium graminearum-infected roots and prevents reduction in biomass of barley shoots through systemic interactions
Soil bacteria such as pseudomonads may reduce pathogen pressure for plants, both by activating plant defence mechanisms and by inhibiting pathogens directly due to the production of antibiotics. These effects are hard to distinguish under field conditions, impairing estimations of their relative contributions to plant health. A split-root system was set up with barley to quantify systemic and local effects of pre-inoculation with Pseudomonas fluorescens on the subsequent infection process by the fungal pathogen Fusarium graminearum. One root half was inoculated with F. graminearum in combination with P. fluorescens strain CHA0 or its isogenic antibiotic-deficient mutant CHA19. Bacteria were inoculated either together with the fungal pathogen or in separate halves of the root system to separate local and systemic effects. The short-term plant response to fungal infection was followed by using the short-lived isotopic tracer 11CO2 to track the delivery of recent photoassimilates to each root half. In the absence of bacteria, fungal infection diverted carbon from the shoot to healthy roots, rather than to infected roots, although the overall partitioning from the shoot to the entire root system was not modified. Both local and systemic pre-inoculation with P. fluorescens CHA0 prevented the diversion of carbon as well as preventing a reduction in plant biomass in response to F. graminearum infection, whereas the non-antibiotic-producing mutant CHA19 lacked this ability. The results suggest that the activation of plant defences is a central feature of biocontrol bacteria which may even surpass the effects of direct pathogen inhibition
Dual mechanism of brain injury and novel treatment strategy in maple syrup urine disease
Maple syrup urine disease (MSUD) is an inherited disorder of branched-chain amino acid metabolism presenting with lifethreatening cerebral oedema and dysmyelination in affected individuals. Treatment requires life-long dietary restriction and monitoring of branched-chain amino acids to avoid brain injury. Despite careful management, children commonly suffer metabolic decompensation in the context of catabolic stress associated with non-specific illness. The mechanisms underlying this decompensation and brain injury are poorly understood. Using recently developed mouse models of classic and intermediate maple syrup urine disease, we assessed biochemical, behavioural and neuropathological changes that occurred during encephalopathy in these mice. Here, we show that rapid brain leucine accumulation displaces other essential amino acids resulting in neurotransmitter depletion and disruption of normal brain growth and development. A novel approach of administering norleucine to heterozygous mothers of classic maple syrup urine disease pups reduced branched-chain amino acid accumulation in milk as well as blood and brain of these pups to enhance survival. Similarly, norleucine substantially delayed encephalopathy in intermediate maple syrup urine disease mice placed on a high protein diet that mimics the catabolic stress shown to cause encephalopathy in human maple syrup urine disease. Current findings suggest two converging mechanisms of brain injury in maple syrup urine disease including: (i) neurotransmitter deficiencies and growth restriction associated with branchedchain amino acid accumulation and (ii) energy deprivation through Krebs cycle disruption associated with branched-chain ketoacid accumulation. Both classic and intermediate models appear to be useful to study the mechanism of brain injury and potential treatment strategies for maple syrup urine disease. Norleucine should be further tested as a potential treatment to prevent encephalopathy in children with maple syrup urine disease during catabolic stress
Mechanism of age-dependent susceptibility and novel treatment strategy in glutaric acidemia type I
Glutaric acidemia type I (GA-I) is an inherited disorder of lysine and tryptophan metabolism presenting with striatal lesions anatomically and symptomatically similar to Huntington disease. Affected children commonly suffer acute brain injury in the context of a catabolic state associated with nonspecific illness. The mechanisms underlying injury and age-dependent susceptibility have been unknown, and lack of a diagnostic marker heralding brain injury has impeded intervention efforts. Using a mouse model of GA-I, we show that pathologic events began in the neuronal compartment while enhanced lysine accumulation in the immature brain allowed increased glutaric acid production resulting in age-dependent injury. Glutamate and GABA depletion correlated with brain glutaric acid accumulation and could be monitored in vivo by proton nuclear magnetic resonance (1H NMR) spectroscopy as a diagnostic marker. Blocking brain lysine uptake reduced glutaric acid levels and brain injury. These findings provide what we believe are new monitoring and treatment strategies that may translate for use in human GA-I
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