Space weather radiation effects on geostationary satellite solid-state power amplifiers

In order to understand and mitigate the effects of space weather on the performance of geostationary (GEO) communications satellites, we analyze 16 years of archived telemetry data from Inmarsat, the UK-based telecommunications company. We compare 665,112 operational hours of housekeeping telemetry from two generations of satellites, designated as Fleet A and Fleet B. Each generation experienced 13 solid-state power amplifier (SSPA) anomalies for a total of 26 anomalies from 1996 to 2012. We compare telemetry from the Inmarsat anomalies with space weather observations, including data from the OMNI2 database, Geostationary Operational Environmental Satellites, the Advanced Composition Explorer Satellite, and Los Alamos National Laboratory (LANL) GEO observations; the evolution of the sunspot number; and the Kp index. Most SSPA anomalies for Fleet A occur as solar activity declines; Fleet B has not yet experienced a full solar cycle. For both fleets, the average value of Kp remained <2 over time periods of 2 days, 3 days, and 2 weeks around the time of anomaly, which suggests that the anomalies occurred at times of relatively quiet geomagnetic activity and that they were probably not solely caused by surface charging. From 1996 to 2009, the average of the 1.8-3.5MeV electron flux was 1.98 #/(cm(2)s st keV). Five of the 26 anomalies, unfortunately, do not have corresponding science observations (specifically, electron flux data in the LANL data set), so part of this study focuses on the 21 anomalies when science observations were available. Six out of 21 anomalies experienced a high-energy electron flux greater than 1.5 standard deviations above the mean of the log(10) of the flux between 7 and 14days prior to the anomaly. By contrast, a Monte Carlo simulation finds that on average, only 2.8 out of 21 (13%) of randomly assigned anomalies occur between 7 and 14days after an electron flux greater than 1.5 standard deviations above the mean. Our observations suggest that internal charging from either past elevated radiation belt fluxes or some conditions related to relativistic electron enhancements (either causally or accidentally) is most likely responsible for the SSPA anomalies. We next consider the timing of these anomalies with respect to the local time (LT) and season. Anomalies occur at all LT sectors with 46% (Fleet A) and 38.5% (Fleet B) in the midnight to dawn sector and 54% (Fleet A) and 46% (Fleet B) in the local noon to dusk sector. From the local time distribution, surface charging does not appear to be the sole causative agent of the anomalies. Understanding the connection between the space weather conditions and anomalies on subsystems and specific components on identical and similar geostationary communications satellites for periods of time longer than a solar cycle will help guide design improvements and provide insight on their operation during space weather events

Habitat Characteristics of Black Crappie Nest Sites in an Illinois Impoundment

Ten nest colonies of black crappie Pomoxis nigromaculatus were visually located and verified by angling in Campus Lake, a small urban impoundment in southern Illinois. Habitat characteristics were measured at these nest sites and compared to habitat measurements obtained from 45 unused sites. Seven habitat characteristics (substrate firmness, temperature, dissolved oxygen, distance to deep water [3.8-m depth contour], substrate type, vegetation height, and vegetation density) were significantly different between nest sites and unused sites. Although temperature and dissolved oxygen were significantly different between nest sites and unused sites, all values were within the suitable range for black crappie spawning to occur. Black crappies selected nest sites close to deep water with firm substrates and low vegetation height and density. Our results present insight on habitat characteristics of black crappie spawning locations in a small urban impoundment. Interestingly, we located several black crappie nesting colonies with more than 10 individual nests in close proximity to one another; colonial nesting by black crappies has not previously been reported in the literature. Furthermore, we suggest that degree of shoreline modification and other anthropogenic influences in and adjacent to Campus Lake did not affect black crappie nest site selection. Black crappie nest sites in Campus Lake were always located near deep water (3.8 m), in low-density, short vegetation, and on firm clay or sand substrate; because nest site selection can influence earlylife survival and recruitment of black crappie, the availability of these habitat characteristics may regulate black crappie population demographics in Campus Lake. Efforts to limit sediment inputs will be important for maintaining suitable black crappie spawning habitat in Campus Lake and other small impoundments

Neurosyphilis manifesting with unilateral visual loss and hyponatremia: a case report

<p>Abstract</p> <p>Background</p> <p>Syphilis is called the chameleon of the diseases due to its variety of its clinical presentations, potentially affecting every organ of the body. Incidence of this ancient disease is once again on the increase worldwide.</p> <p>Case presentation</p> <p>We here report an unusual case of neurosyphilis manifesting with unilateral visual loss and hyponatremia. The patient also had primary syphilitic lesions and was concomitantly diagnosed with Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) infection. Treatment with ceftriaxone and prednisolone, completely resolved the hyponatremia and visual acuity was partially restored.</p> <p>Conclusion</p> <p>Awareness of syphilis as a differential diagnosis is important as previously unreported presentations of neurosyphilis can arise, especially in HIV infected patients.</p

Towards a new phenotype for tick resistance in beef and dairy cattle:a review

About 80% of the world's cattle are affected by ticks and tick-borne diseases, both of which cause significant production losses. Cattle host resistance to ticks is the most important factor affecting the economics of tick control, but it is largely neglected in tick-control programs due to technical difficulties and costs associated with identifying individual-animal variation in resistance. The present paper reviews the scientific literature to identify factors affecting resistance of cattle to ticks and the biological mechanisms of host tick resistance, to develop alternative phenotype(s) for tick resistance. If new cost-effective phenotype(s) can be developed and validated, then tick resistance of cattle could be genetically improved using genomic selection, and incorporated into breeding objectives to simultaneously improve cattle productive attributes and tick resistance. The phenotype(s) could also be used to improve tick control by using cattle management. On the basis of the present review, it is recommended that three possible phenotypes (haemolytic analysis measures of skin hypersensitivity reactions simplified artificial tick infestations) be further developed to determine their practical feasibility for consistently, cost-effectively and reliably measuring cattle tick resistance in thousands of individual animals in commercial and smallholder farmer herds in tropical and subtropical areas globally. During evaluation of these potential new phenotypes, additional measurements should be included to determine the possibility of developing a volatile-based resistance phenotype, to simultaneously improve cattle resistance to both ticks and biting flies. Because the current measurements of volatile chemistry do not satisfy the requirements of a simple, cost-effective phenotype for use in commercial cattle herds, consideration should also be given to inclusion of potentially simpler measures to enable indirect genetic selection for volatile-based resistance to ticks

Circulating microRNAs in sera correlate with soluble biomarkers of immune activation but do not predict mortality in ART treated individuals with HIV-1 infection: A case control study

Introduction: The use of anti-retroviral therapy (ART) has dramatically reduced HIV-1 associated morbidity and mortality. However, HIV-1 infected individuals have increased rates of morbidity and mortality compared to the non-HIV-1 infected population and this appears to be related to end-organ diseases collectively referred to as Serious Non-AIDS Events (SNAEs). Circulating miRNAs are reported as promising biomarkers for a number of human disease conditions including those that constitute SNAEs. Our study sought to investigate the potential of selected miRNAs in predicting mortality in HIV-1 infected ART treated individuals. Materials and Methods: A set of miRNAs was chosen based on published associations with human disease conditions that constitute SNAEs. This case: control study compared 126 cases (individuals who died whilst on therapy), and 247 matched controls (individuals who remained alive). Cases and controls were ART treated participants of two pivotal HIV-1 trials. The relative abundance of each miRNA in serum was measured, by RTqPCR. Associations with mortality (all-cause, cardiovascular and malignancy) were assessed by logistic regression analysis. Correlations between miRNAs and CD4+ T cell count, hs-CRP, IL-6 and D-dimer were also assessed. Results: None of the selected miRNAs was associated with all-cause, cardiovascular or malignancy mortality. The levels of three miRNAs (miRs -21, -122 and -200a) correlated with IL-6 while miR-21 also correlated with D-dimer. Additionally, the abundance of miRs -31, -150 and -223, correlated with baseline CD4+ T cell count while the same three miRNAs plus miR- 145 correlated with nadir CD4+ T cell count. Discussion: No associations with mortality were found with any circulating miRNA studied. These results cast doubt onto the effectiveness of circulating miRNA as early predictors of mortality or the major underlying diseases that contribute to mortality in participants treated for HIV-1 infection