17,906 research outputs found

    Evaluation of expected solar flare neutrino events in the IceCube observatory

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    Since the end of the eighties and in response to a reported increase in the total neutrino flux in the Homestake experiment in coincidence with a solar flare, solar neutrino detectors have searched for solar flare signals. Neutrinos from the decay of mesons, which are themselves produced in collisions of accelerated protons with the solar atmosphere, would provide a novel window on the underlying physics of the acceleration process. For our studies we focus on the IceCube Neutrino Observatory, a cubic kilometer neutrino detector located at the geographical South Pole. Due to its Supernova data acquisition system and its DeepCore component, dedicated to low energy neutrinos, IceCube may be sensitive to solar flare neutrinos and thus permit either a measurement of the signal or the establishment of more stringent upper limits on the solar flare neutrino flux. We present an approach for a time profile analysis based on a stacking method and an evaluation of a possible solar flare signal in IceCube using the Geant4 toolkit.Comment: Paper submitted to the 34th International Cosmic Ray Conference, The Hague 201

    Malmquist Bias and the Distance to the Virgo Cluster

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    This paper investigates the impact of Malmquist bias on the distance to the Virgo cluster determined by the H_0 Key Project using M100, and consequently on the derived value of H_0. Malmquist bias is a volume-induced statistical effect which causes the most probable distance to be different from the raw distance measured. Consideration of the bias in the distance to the Virgo cluster raises this distance and lowers the calculated value of H_0. Monte Carlo simulations of the cluster have been run for several possible distributions of spirals within the cluster and of clusters in the local universe. Simulations consistent with known information regarding the cluster and the errors of measurement result in a bias of about 6.5%-8.5%. This corresponds to an unbiased distance of 17.2-17.4 Mpc and a value of H_0 in the range 80-82 km/s/Mpc. The problem of determining the bias to Virgo illustrates several key points regarding Malmquist bias. Essentially all conventional astronomical distance measurements are subject to this bias. In addition, the bias accumulates when an attempt is made to construct "distance ladders" from measurements which are individually biased. As will be shown in the case of Virgo, the magnitude and direction of the bias are sensitive to the spatial distribution of the parent poputation from which the observed object is drawn - a distribution which is often poorly known. This leads to uncertainty in the magnitude of the bias, and adds to the importance of minimizing the number of steps in "distance ladders".Comment: 19 pages, 3 figures, Latex, To appear in Ap

    Analysis of pilot control strategy

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    Methods for nonintrusive identification of pilot control strategy and task execution dynamics are presented along with examples based on flight data. The specific analysis technique is Nonintrusive Parameter Identification Procedure (NIPIP), which is described in a companion user's guide (NASA CR-170398). Quantification of pilot control strategy and task execution dynamics is discussed in general terms followed by a more detailed description of how NIPIP can be applied. The examples are based on flight data obtained from the NASA F-8 digital fly by wire airplane. These examples involve various piloting tasks and control axes as well as a demonstration of how the dynamics of the aircraft itself are identified using NIPIP. Application of NIPIP to the AFTI/F-16 flight test program is discussed. Recommendations are made for flight test applications in general and refinement of NIPIP to include interactive computer graphics

    Effect of time and rate of application of anhydrous ammonia and urea with or without a nitrification inhibitor on the yield and quality of a barley-wheat-canola rotation

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    Non-Peer ReviewedA project was initiated in the fall of 2006 to compare the effect of early (mid-September) and late (mid to late October) fall, and spring application of anhydrous ammonia and urea on the yield of barley, wheat and canola in barley-wheat-canola-wheat rotation. The experiment now in its third year is being carried out in two locations (Watrous and Lake Lenore) and involves four rates of N (0, 30, 80 and 120 kg N ha-1) with or without treatment with a nitrification inhibitor (N-Serve) annually applied on the same plots and four replicates for a total of 39 treatments. Consistent significant differences in all six-site years were responses to N and anhydrous vs. urea, the latter being a result of the inefficiency of the low N rate (40 kg ha-1) when applied as anhydrous ammonia. Overall, there were no differences due to time of application

    The hydrology of prehistoric farming systems in a central Arizona ecotone

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    The prehistoric land use and water management in the semi-arid Southwest was examined. Remote sensing data, geology, hydrology and biology are discussed along with an evaluation of remote sensing contributions, recommendations for applications, and proposed future remote sensing studies

    Fantasy-driven versus contact-driven users of child sexual exploitation material: offender classification and implications for their risk assessment

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    Since the advent of the internet, convictions for the possession, display, trading and distribution of child sexual exploitation material (CSEM) have risen steadily, but little is known about the appropriate assessment and treatment of this offender group, especially in regards to their risk of reoffending. It has been suggested that a conceptual distinction of fantasy- vs. contact-driven CSEM users might be of merit. Sixty-eight offenders recruited from sex offender treatment providers were assessed via an anonymous computer survey including a variety of clinical and risk-related variables; the findings showed differences in the psychological profiles between CSEM users and contact child sex offenders. Numerical and spatial methods were employed to identify subgroups of CSEM users; these confirmed the two-fold distinction of fantasy vs. contact driven offending. The spatial representation of participants identified three dimensions as crucial in the classification of these subgroups: direct sexual contact with a minor, possession of fantasy-generating material, and social contact with other users with a sexual interest in minors, potentially differentiating distinct offender subgroups with different risks and needs. The current study informed the development of an empirical model of CSEM users that could aid in the assessment of risk of reoffending and cross-over to contact sex offending

    Costs Associated with Malaria in Pregnancy in the Brazilian Amazon, a Low Endemic Area Where Plasmodium vivax Predominates.

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    BACKGROUND: Information on costs associated with malaria in pregnancy (MiP) in low transmission areas where Plasmodium vivax predominates is so far missing. This study estimates health system and patient costs of MiP in the Brazilian Amazon. METHODS/PRINCIPAL FINDINGS: Between January 2011 and March 2012 patient costs for the treatment of MiP were collected through an exit survey at a tertiary referral hospital and at a primary health care centre in the Manaus metropolitan area, Amazonas state. Pregnant and post-partum women diagnosed with malaria were interviewed after an outpatient consultation or at discharge after admission. Seventy-three interviews were included in the analysis. Ninety-six percent of episodes were due to P. vivax and 4% to Plasmodium falciparum. In 2010, the total median costs from the patient perspective were estimated at US 45.91andUS45.91 and US 216.29 for an outpatient consultation and an admission, respectively. When multiple P. vivax infections during the same pregnancy were considered, patient costs increased up to US 335.85,representingthecostsofanadmissionplusanoutpatientconsultation.Providerdirectandoverheadcostdatawereobtainedfromseveralsources.Theprovidercostassociatedwithanoutpatientcase,whichincludesseveralconsultationsatthetertiaryhospitalwasUS335.85, representing the costs of an admission plus an outpatient consultation. Provider direct and overhead cost data were obtained from several sources. The provider cost associated with an outpatient case, which includes several consultations at the tertiary hospital was US 103.51 for a P. vivax malaria episode and US 83.59foraP.falciparummalariaepisode.Thecostofaninpatientdayandaverageadmissionof3dayswasUS83.59 for a P. falciparum malaria episode. The cost of an inpatient day and average admission of 3 days was US 118.51 and US 355.53,respectively.TotalprovidercostsforthediagnosisandtreatmentofallmalariacasesreportedinpregnantwomeninManausin2010(N=364)wereUS355.53, respectively. Total provider costs for the diagnosis and treatment of all malaria cases reported in pregnant women in Manaus in 2010 (N = 364) were US 17,038.50, of which 92.4% (US$ 15,741.14) due to P. vivax infection. CONCLUSION: Despite being an area of low risk malaria transmission, MiP is responsible for a significant economic burden in Manaus. Especially when multiple infections are considered, costs associated with P. vivax are higher than costs associated with P. falciparum. The information generated may help health policy decisions for the current control and future elimination of malaria in the area

    Cantu syndrome–associated SUR2 (ABCC9) mutations in distinct structural domains result in KATP channel gain-of-function by differential mechanisms

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    The complex disorder Cantu syndrome (CS) arises from gainof-function mutations in either KCNJ8 or ABCC9, the genes encoding the Kir6.1 and SUR2 subunits of ATP-sensitive potassium (KATP) channels, respectively. Recent reports indicate that such mutations can increase channel activity by multiple molecular mechanisms. In this study, we determined the mechanism by which KATP function is altered by several substitutions in distinct structural domains of SUR2: D207E in the intracellular L0-linker and Y985S, G989E, M1060I, and R1154Q/R1154W in TMD2. We engineered substitutions at their equivalent positions in rat SUR2A (D207E, Y981S, G985E, M1056I, and R1150Q/R1150W) and investigated functional consequences using macroscopic rubidium (86Rb-) efflux assays and patchclamp electrophysiology. Our results indicate that D207E increases KATP channel activity by increasing intrinsic stability of the open state, whereas the cluster of Y981S/G985E/M1056I substitutions, as well as R1150Q/R1150W, augmented Mg-nucleotide activation. We also tested the responses of these channel variants to inhibition by the sulfonylurea drug glibenclamide, a potential pharmacotherapy for CS. None of the D207E, Y981S, G985E, or M1056I substitutions had a significant effect on glibenclamide sensitivity. However, Gln and Trp substitution at Arg-1150 significantly decreased glibenclamide potency. In summary, these results provide additional confirmation that mutations in CS-Associated SUR2 mutations result in KATP gain-of-function. They help link CS genotypes to phenotypes and shed light on the underlying molecular mechanisms, including consequences for inhibitory drug sensitivity, insights that may inform the development of therapeutic approaches to manage CS

    Electronic Structure of Cytochrome P450

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    The optical properties of P450 have been investigated by means of polarized absorption spectroscopy of single crystals of camphor- bound P450CAM in the oxidized, reduced, and CO-reduced states, and iterative extended Ruckel (IEH) calculations. The heme chromophores are orientated such that transitions polarized in the heme plane (x,y-polarized) can be readily distinguished from transitions polarized perpendicular to the heme plane (z-polarized) . High spin oxidized P450 exhibits two broad z-polarized bands, at 567 and 323 nm. IEH calculations suggest that these bands arise from cysteine mercaptide sulfur-to-iron charge transfer transitions. High spin reduced P450 has no z-polarized bands. IEH calculations suggest that loss of these bands occurs because the cysteine sulfur is protonated to a mercaptan. Low spin CO-P450 has an intense x,y-polarized band at 363 nm. This transition, assigned as a mercaptide sulfur-to-porphyrin charge transfer transition, has the correct symmetry to mix with the Soret and may cause the anomalous red shift of the Soret
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