13,521 research outputs found

    Time Evolution of Elemental Ratios in Solar Energetic Particle events

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    Heavy ion ratio abundances in Solar Energetic Particle (SEP) events, e.g. Fe/O, often exhibit decreases over time. Using particle instruments on the ACE, SOHO and STEREO spacecraft, we analysed heavy ion data from 4 SEP events taking place between December 2006 and December 2014. We constructed 36 different ionic pairs and studied their time evolution in each event. We quantified the temporal behaviour of abundant SEP ratios by fitting the data to derive a decay time constant B. We also considered the ratio of ionic mass–to–charge for each pair, the S value given e.g. for Fe/O by SFe/O = (M/Q)Fe/(M/Q)O. We found that the temporal behaviour of SEP ratios is ordered by the value of S: ratios with S > 1 showed decreases over time (i.e. B 0). We plotted B as a function of S and observed a clear monotonic dependence: ratios with a large S decayed at a higher rate. A prominent discontinuity at S = 2.0 (corresponding to He/H) was found in 3 of the 4 events, suggesting anomalous behaviour of protons. The X/H ratios often show an initial increase followed by a decrease, and decay at a slower rate. We discuss possible causes of the observed B versus S trends within current understanding of SEP propagation

    A Probabilistic proof of the breakdown of Besov regularity in LL-shaped domains

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    {We provide a probabilistic approach in order to investigate the smoothness of the solution to the Poisson and Dirichlet problems in LL-shaped domains. In particular, we obtain (probabilistic) integral representations for the solution. We also recover Grisvard's classic result on the angle-dependent breakdown of the regularity of the solution measured in a Besov scale

    The 2013 clinical course descriptors for multiple sclerosis: A clarification

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    The clinical courses of multiple sclerosis were defined in 1996 and refined in 2013 to provide a time-based assessment of the current status of the individual. These definitions have been successfully used by clinicians, clinical trialists, and regulatory authorities. Recent regulatory decisions produced variations and discrepancies in the use of the clinical course descriptions. We provide here a clarification of the concepts underlying these descriptions and restate the principles used in their development. Importantly, we highlight the critical importance of time framing the disease course modifiers activity and progression and clarify the difference between the terms worsening and progressing

    Do adults with high functioning autism or Asperger Syndrome differ in empathy and emotion recognition?

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    The present study examined whether adults with high functioning autism (HFA) showed greater difficulties in (i) their self-reported ability to empathise with others and/or (ii) their ability to read mental states in others’ eyes than adults with Asperger syndrome (AS). The Empathy Quotient (EQ) and ‘Reading the Mind in the Eyes’ Test (Eyes Test) were compared in 43 adults with AS and 43 adults with HFA. No significant difference was observed on EQ score between groups, while adults with AS performed significantly better on the Eyes Test than those with HFA. This suggests that adults with HFA may need more support, particularly in mentalizing and complex emotion recognition, and raises questions about the existence of subgroups within autism spectrum conditions

    Lights, Camera, Action! Exploring Effects of Visual Distractions on Completion of Security Tasks

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    Human errors in performing security-critical tasks are typically blamed on the complexity of those tasks. However, such errors can also occur because of (possibly unexpected) sensory distractions. A sensory distraction that produces negative effects can be abused by the adversary that controls the environment. Meanwhile, a distraction with positive effects can be artificially introduced to improve user performance. The goal of this work is to explore the effects of visual stimuli on the performance of security-critical tasks. To this end, we experimented with a large number of subjects who were exposed to a range of unexpected visual stimuli while attempting to perform Bluetooth Pairing. Our results clearly demonstrate substantially increased task completion times and markedly lower task success rates. These negative effects are noteworthy, especially, when contrasted with prior results on audio distractions which had positive effects on performance of similar tasks. Experiments were conducted in a novel (fully automated and completely unattended) experimental environment. This yielded more uniform experiments, better scalability and significantly lower financial and logistical burdens. We discuss this experience, including benefits and limitations of the unattended automated experiment paradigm

    Calculating the random guess scores of multiple-response and matching test items

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    For achievement tests, the guess score is often used as a baseline for the lowest possible grade for score to grade transformations and setting the cut scores. For test item types such as multiple-response, matching and drag-and-drop, determin-ing the guess score requires more elaborate calculations than the more straight-forward calculation of the guess score for True-False and multiple-choice test item formats. For various variants of multiple-response and matching types with respect to dichotomous and polytomous scoring, methods for determining the guess score are presented and illustrated with practical applications. The implica-tions for theory and practice are discussed

    The structure of a resuscitation-promoting factor domain from Mycobacterium tuberculosis shows homology to lysozymes

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    Resuscitation-promoting factor (RPF) proteins reactivate stationary-phase cultures of (G+C)-rich Gram-positive bacteria including the causative agent of tuberculosis, Mycobacterium tuberculosis. We report the solution structure of the RPF domain from M. tuberculosis Rv1009 (RpfB) solved by heteronuclear multidimensional NMR. Structural homology with various glycoside hydrolases suggested that RpfB cleaved oligosaccharides. Biochemical studies indicate that a conserved active site glutamate is important for resuscitation activity. These data, as well as the presence of a clear binding pocket for a large molecule, indicate that oligosaccharide cleavage is probably the signal for revival from dormancy

    A TRAIL-R1-specific ligand in combination with doxorubicin selectively targets primary breast tumour cells for apoptosis

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    A TRAIL-R1-specific ligand in combination with doxorubicin selectively targets primary breast tumour cells for apoptosi

    Measuring Potential Dermal Transfer of a Pesticide to Children in a Child Care Center

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    Currently, the major determinants of children’s exposure to pesticides are not fully understood, and approaches for measuring and assessing dermal exposure in a residential setting have not been sufficiently evaluated. In one approach, dermal exposure is estimated using empirically derived transfer coefficients. To assess the feasibility of using this approach for assessing children’s exposure to pesticides, we conducted a study was conducted in a child care center that had a preexisting contract with a pest control service for regular monthly pesticide applications. Children in the selected child care center were monitored using full-body cotton garments to measure dermal loading. Pesticide residues on classroom surfaces were measured in the areas where the children spent time. Measured surface-wipe loadings ranged from 0.47 to 120 ng/cm(2), and total garment loadings ranged from 0.5 to 660 pg/cm(2). The garment and surface loading measurements were used to calculate dermal-transfer coefficients for use in assessing children’s residential exposure to pesticides. Dermal-transfer coefficients calculated using these data range from approximately 10 to 6,000 cm(2)/hr. The wide range in these values demonstrates the importance of developing standard surface-measurement protocols if this approach is to be used to assess dermal exposure in a residential environment. The upper-range values resulting from this study were found to be similar to the default value used by the U.S. Environmental Protection Agency to assess children’s dermal exposures resulting from contact with indoor surfaces
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