384 research outputs found

    High fidelity simulations of ion trajectories in miniature ion traps using the boundary-element method

    Full text link
    In this paper we present numerical modeling results for endcap and linear ion traps, used for experiments at the National Physical Laboratory in the UK and Innsbruck University respectively. The secular frequencies for Strontium-88 and Calcium-40 ions were calculated from ion trajectories, simulated using boundary-element and finite-difference numerical methods. The results were compared against experimental measurements. Both numerical methods showed high accuracy with boundary-element method being more accurate. Such simulations can be useful tools for designing new traps and trap arrays. They can also be used for obtaining precise trapping parameters for desired ion control when no analytical approach is possible as well as for investigating the ion heating rates due to thermal electronic noise.Comment: 6 pages, 5 figures, changes made to the text according to the editor's and referee's comment

    Detecting explosive-device emplacement at multiple granularities

    Get PDF
    This paper appeared in the Proceedings of the Military Sensing Society (MSS) National Symposium, Las Vegas, Nevada, U.S., July 2010.We report on experiments with a nonimaging sensor network for detection of suspicious behavior related to pedestrian emplacement of IEDs. Emplacement is the time when detection is the most feasible for IEDs since it almost necessarily must involve some unusual behaviors. Sensors at particularly dangerous locations such as bridges, culverts, road narrowings, and road intersections could provide early warning of such activity. Imaging for surveillance has weaknesses in its susceptibility to occlusion, problems operating at night, sensitivity to angle of view, high processing requirements, and need to invade privacy. Our approach is to use a variety of nonimaging sensors with different modalities to track people. We particularly look for clues as to accelerations since these are often associated with suspicious behavior. Our approach involves preanalyzing terrain for the probability of emplacement of an IED, then combining this with real-time assessment of suspicious behavior obtained from probabilities of location derived from sensor data. We describe some experiments with a prototype sensor network and the promising results obtained.supported by the U.S. National Science Foundation under grant 0729696 of the EXP ProgramApproved for public release; distribution is unlimited

    The diversity, evolution and ecology of Salmonella in venomous snakes

    Get PDF
    BACKGROUND: Reptile-associated Salmonella bacteria are a major, but often neglected cause of both gastrointestinal and bloodstream infection in humans globally. The diversity of Salmonella enterica has not yet been determined in venomous snakes, however other ectothermic animals have been reported to carry a broad range of Salmonella bacteria. We investigated the prevalence and diversity of Salmonella in a collection of venomous snakes and non-venomous reptiles. METHODOLOGY/PRINCIPLE FINDINGS: We used a combination of selective enrichment techniques to establish a unique dataset of reptilian isolates to study Salmonella enterica species-level evolution and ecology and used whole-genome sequencing to investigate the relatedness of phylogenetic groups. We observed that 91% of venomous snakes carried Salmonella, and found that a diverse range of serovars (n = 58) were carried by reptiles. The Salmonella serovars belonged to four of the six Salmonella enterica subspecies: diarizonae, enterica, houtanae and salamae. Subspecies enterica isolates were distributed among two distinct phylogenetic clusters, previously described as clade A (52%) and clade B (48%). We identified metabolic differences between S. diarizonae, S. enterica clade A and clade B involving growth on lactose, tartaric acid, dulcitol, myo-inositol and allantoin. SIGNIFICANCE: We present the first whole genome-based comparative study of the Salmonella bacteria that colonise venomous and non-venomous reptiles and shed new light on Salmonella evolution. Venomous snakes examined in this study carried a broad range of Salmonella, including serovars which have been associated with disease in humans such as S. Enteritidis. The findings raise the possibility that venomous snakes could be a reservoir for Salmonella serovars associated with human salmonellosis

    <sup>14</sup>N NQR, relaxation and molecular dynamics of the explosive TNT

    Get PDF
    Multiple pulse sequences are widely used for signal enhancement in NQR detection applications. Since the various 14N NQR relaxation times, signal decay times and frequency of each NQR line have a major influence on detection sequence performance, it is important to characterise these parameters and their temperature variation, as fully as possible. In this paper we discuss such measurements for a number of the ν+ and ν- NQR lines of monoclinic and orthorhombic TNT and relate the temperature variation results to molecular dynamics. The temperature variation of the 14N spin-lattice relaxation times T1 is interpreted as due to hindered rotation of the NO2 group about the C-NO2 bond with an activation energy of 89 kJ mol-1 for the ortho and para groups of monoclinic TNT and 70 kJ mol-1 for the para group of orthorhombic TNT.</p

    Triadic Interactions in MIECHV: Relations to Home Visit Quality

    Get PDF
    Objectives This study was conducted to look inside home visits to examine active intervention ingredients used and their relations with ratings of home visit quality. In particular, triadic interactions that engage the home visitor, parent, and child together and provide a context for home visitors to facilitate parent-child interactions by observing, modeling and coaching behaviors that promote optimal child development were examined. Methods Observations were conducted to describe intervention activities (with the HVOF-R) and rate quality of home visit practices and engagement (with the HOVRS A+). Results Analyses revealed the majority of home visit time (71%) was spent in home visitor-parent interactions with only a small proportion of home visit time (17%) spent in triadic interactions and an even smaller proportion of time (2%) during which home visitors actively coached parent-child interactions. Amount of time spent in triadic interactions was related positively to quality ratings of home visit practices and engagement. Moreover, time spent coaching parent-child interactions uniquely predicted home visit quality after accounting for visit length and home visitor time spent observing and modeling. Conclusions for Practice Increasing the percentage of home visitors engage the parent and child in triadic interaction should be a focus for home visiting programs. Home visitors will likely need professional development and supervisory support to enhance their skills in coaching parent-child interactions during triadic interactions

    The Mass of KOI-94d and a Relation for Planet Radius, Mass, and Incident Flux

    Get PDF
    We measure the mass of a modestly irradiated giant planet, KOI-94d. We wish to determine whether this planet, which is in a 22 day orbit and receives 2700 times as much incident flux as Jupiter, is as dense as Jupiter or rarefied like inflated hot Jupiters. KOI-94 also hosts at least three smaller transiting planets, all of which were detected by the Kepler mission. With 26 radial velocities of KOI-94 from the W. M. Keck Observatory and a simultaneous fit to the Kepler light curve, we measure the mass of the giant planet and determine that it is not inflated. Support for the planetary interpretation of the other three candidates comes from gravitational interactions through transit timing variations, the statistical robustness of multi-planet systems against false positives, and several lines of evidence that no other star resides within the photometric aperture. We report the properties of KOI-94b (M_P = 10.5 ± 4.6 M_⊕, R_P = 1.71 ± 0.16 R_⊕, P = 3.74 days), KOI-94c (M_P = 15.6^(+5.7)_(-15.6) M_⊕, R_P = 4.32 ± 0.41 R_⊕, P = 10.4 days), KOI-94d (M_P = 106 ± 11 M_⊕, R_P = 11.27 ± 1.06 R_⊕, P = 22.3 days), and KOI-94e (M_P = 35^(+18)_(-28) M_⊕, R_P = 6.56 ± 0.62 R_⊕, P = 54.3 days). The radial velocity analyses of KOI-94b and KOI-94e offer marginal (>2σ) mass detections, whereas the observations of KOI-94c offer only an upper limit to its mass. Using the KOI-94 system and other planets with published values for both mass and radius (138 exoplanets total, including 35 with M_P 150 M_⊕. These equations can be used to predict the radius or mass of a planet

    Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

    Get PDF
    Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

    Face perception enhances insula and motor network reactivity in Tourette syndrome

    Get PDF
    Tourette syndrome is a neurodevelopmental disorder, characterised by motor and phonic tics. Tics are typically experienced as avolitional, compulsive, and associated with premonitory urges. They are exacerbated by stress and can be triggered by external stimuli, including social cues like the actions and facial expressions of others. Importantly, emotional social stimuli, with angry facial stimuli potentially the most potent social threat cue, also trigger behavioural reactions in healthy individuals, suggesting that such mechanisms may be particularly sensitive in people with Tourette syndrome. Twenty-one participants with Tourette syndrome and 21 healthy controls underwent functional magnetic resonance imaging while viewing faces wearing either neutral or angry expressions to quantify group differences in neural activity associated with processing social information. Simultaneous video recordings of participants during neuroimaging enabled us to model confounding effects of tics on task-related responses to the processing of faces. In both Tourette syndrome and control participants, face stimuli evoked enhanced activation within canonical face perception regions, including the occipital face area and fusiform face area. However, the Tourette syndrome group showed additional responses within the anterior insula to both neutral and angry faces. Functional connectivity during face viewing was then examined in a series of psychophysiological interactions. In Tourette syndrome participants, the insula showed functional connectivity with a set of cortical regions previously implicated in tic generation: the pre-supplementary motor area, premotor cortex, primary motor cortex, and the putamen. Furthermore, insula functional connectivity with the globus pallidus and thalamus varied in proportion to tic severity, while supplementary motor area connectivity varied in proportion to premonitory sensations, with insula connectivity to these regions increasing to a greater extent in patients with worse symptom severity. In addition, the occipital face area showed increased functional connectivity in Tourette syndrome participants with posterior cortical regions, including primary somatosensory cortex, and occipital face area connectivity with primary somatosensory and primary motor cortices varied in proportion to tic severity. There were no significant psychophysiological interactions in controls. These findings highlight a potential mechanism in Tourette syndrome through which heightened representation within insular cortex of embodied affective social information may impact the reactivity of subcortical motor pathways, supporting programmed motor actions that are causally implicated in tic generation. Medicinal and psychological therapies that focus on reducing insular hyper-reactivity to social stimuli may have potential benefit for tic reduction in people with Tourette syndrome

    Taxonomy based on science is necessary for global conservation

    Get PDF
    Peer reviewe

    Correction to: Uncovering spatiotemporal patterns of atrophy in progressive supranuclear palsy using unsupervised machine learning

    Get PDF
    This is a correction to: William J Scotton, Cameron Shand, Emily Todd, Martina Bocchetta, David M Cash, Lawren VandeVrede, Hilary Heuer, PROSPECT Consortium, 4RTNI Consortium, Alexandra L Young, Neil Oxtoby, Daniel C Alexander, James B Rowe, Huw R Morris, Adam L Boxer, Jonathan D Rohrer, Peter A Wijeratne, Uncovering spatiotemporal patterns of atrophy in progressive supranuclear palsy using unsupervised machine learning, Brain Communications, Volume 5, Issue 2, 2023, https://doi.org/10.1093/braincomms/fcad04
    corecore