3,710 research outputs found

    Cluster time measurement with CEPC calorimeter

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    We have developed an algorithm dedicated to timing reconstruction in highly granular calorimeters (HGC). The performance of this algorithm is evaluated on an electromagnetic calorimeter (ECAL) with geometries comparable to the electromagnetic compartment (CE-E) of the CMS endcap calorimeter upgrade at HL-LHC and conceptual Particle Flow oriented ECAL's for future Higgs factories. The time response of individual channel is parameterized according to the CMS experimental result. The particle Time-of-Flight (ToF) can be measured with a resolution of 520  ps5\sim20 \;\rm{ps} for electromagnetic (EM) showers and 80160  ps80\sim 160 \;\rm{ps} for hadronic showers above 1 GeV. The presented algorithm can significantly improve the time resolution, compared to a simple averaging of the fast component of the time spectrum. The effects of three detector configurations are also quantified in this study. ToF resolution depends linearly on the timing resolution of a single silicon sensor and improves statistically with increasing incident particle energy. A clustering algorithm that vetos isolated hits improves ToF resolution.Comment: 12 pages, 32 figure

    Transcriptional profiling of Actinobacillus pleuropneumoniae during the acute phase of a natural infection in pigs

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    <p>Abstract</p> <p>Background</p> <p><it>Actinobacillus pleuropneumoniae </it>is the etiological agent of porcine pleuropneumonia, a respiratory disease which causes great economic losses worldwide. Many virulence factors are involved in the pathogenesis, namely capsular polysaccharides, RTX toxins, LPS and many iron acquisition systems. In order to identify genes that are expressed <it>in vivo </it>during a natural infection, we undertook transcript profiling experiments with an <it>A. pleuropneumoniae </it>DNA microarray, after recovery of bacterial mRNAs from serotype 5b-infected porcine lungs. AppChip2 contains 2033 PCR amplicons based on the genomic sequence of <it>App </it>serotype 5b strain L20, representing more than 95% of ORFs greater than 160 bp in length.</p> <p>Results</p> <p>Transcriptional profiling of <it>A. pleuropneumoniae </it>recovered from the lung of a pig suffering from a natural infection or following growth of the bacterial isolate in BHI medium was performed. An RNA extraction protocol combining beadbeating and hot-acid-phenol was developed in order to maximize bacterial mRNA yields and quality following total RNA extraction from lung lesions. Nearly all <it>A. pleuropneumoniae </it>transcripts could be detected on our microarrays, and 150 genes were deemed differentially expressed <it>in vivo </it>during the acute phase of the infection. Our results indicate that, for example, gene <it>apxIVA </it>from an operon coding for RTX toxin ApxIV is highly up-regulated <it>in vivo</it>, and that two genes from the operon coding for type IV fimbriae (APL_0878 and APL_0879) were also up-regulated. These transcriptional profiling data, combined with previous comparative genomic hybridizations performed by our group, revealed that 66 out of the 72 up-regulated genes are conserved amongst all serotypes and that 3 of them code for products that are predicted outer membrane proteins (genes <it>irp </it>and <it>APL_0959</it>, predicted to code for a TonB-dependent receptor and a filamentous hemagglutinin/adhesin respectively) or lipoproteins (gene <it>APL_0920</it>). Only 4 of 72 up-regulated genes had previously been identified in controled experimental infections.</p> <p>Conclusions</p> <p>These genes that we have identified as up-regulated in <it>vivo</it>, conserved across serotypes and coding for potential outer membrane proteins represent potential candidates for the development of a cross-protective vaccine against porcine pleuropneumonia.</p

    malT knockout mutation invokes a stringent type gene-expression profile in Actinobacillus pleuropneumoniae in bronchoalveolar fluid

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    Actinobacillus pleuropneumoniae causes contagious pleuropneumonia, an economically important disease of commercially reared pigs throughout the world. To cause this disease, A. pleuropneumoniae must rapidly overcome porcine pulmonary innate immune defenses. Since bronchoalveolar fluid (BALF) contains many of the innate immune and other components found in the lungs, we examined the gene expression of a virulent serovar 1 strain of A. pleuropneumoniae after exposure to concentrated BALF for 30 min.Peer reviewed: YesNRC publication: Ye

    Combining Clickstream Analyses and Graph-Modeled Data Clustering for Identifying Common Response Processes

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    Complex interactive test items are becoming more widely used in assessments. Being computer-administered, assessments using interactive items allow logging time-stamped action sequences. These sequences pose a rich source of information that may facilitate investigating how examinees approach an item and arrive at their given response. There is a rich body of research leveraging action sequence data for investigating examinees’ behavior. However, the associated timing data have been considered mainly on the item-level, if at all. Considering timing data on the action-level in addition to action sequences, however, has vast potential to support a more fine-grained assessment of examinees’ behavior. We provide an approach that jointly considers action sequences and action-level times for identifying common response processes. In doing so, we integrate tools from clickstream analyses and graph-modeled data clustering with psychometrics. In our approach, we (a) provide similarity measures that are based on both actions and the associated action-level timing data and (b) subsequently employ cluster edge deletion for identifying homogeneous, interpretable, well-separated groups of action patterns, each describing a common response process. Guidelines on how to apply the approach are provided. The approach and its utility are illustrated on a complex problem-solving item from PIAAC 2012

    Measuring Gravitational Wave Speed and Lorentz Violation with the First Three Gravitational-Wave Catalogs

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    The speed of gravitational waves vgv_g can be measured with the time delay between gravitational-wave detectors. Our study provides a more precise measurement of vgv_g using gravitational-wave signals only, compared with previous studies. We select 52 gravitational-wave events that were detected with high confidence by at least two detectors in the first three observing runs (O1, O2, and O3) of Advanced LIGO and Advanced Virgo. We use Markov chain Monte Carlo and nested sampling to estimate the vgv_g posterior distribution for each of those events. We then combine their posterior distributions to find the 90% credible interval of the combined vgv_g distribution for which we obtain 0.990.02+0.02c0.99^{+0.02}_{-0.02}c without the use of more accurate sky localization from the electromagnetic signal associated with GW170817. Restricting attention to the 50 binary black hole events generates the same result, while the use of the electromagnetic sky localization for GW170817 gives a tighter constraint of 0.990.02+0.01c0.99^{+0.01}_{-0.02}c. The abundance of gravitational wave events allows us to apply hierarchical Bayesian inference on the posterior samples to simultaneously constrain all nine coefficients for Lorentz violation in the nondispersive, nonbirefringent limit of the gravitational sector of the Standard-Model Extension test framework. We compare the hierarchical Bayesian inference method with other methods of combining limits on Lorentz violation in the gravity sector that are found in the literature.Comment: 17 pages, 4 figures, 3 table

    Excited-state OH Mainline Masers in AU Geminorum and NML Cygni

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    Excited-state OH maser emission has previously been reported in the circumstellar envelopes of only two evolved stars: the Mira star AU Geminorum and the hypergiant NML Cygni. We present Very Large Array (VLA) observations of the 1665, 1667, and excited-state 4750 MHz mainline OH transitions in AU Gem and Expanded Very Large Array (EVLA) observations of the excited-state 6030 and 6035 MHz OH mainline transitions in NML Cyg. We detect masers in both mainline transitions in AU Gem but no excited-state emission in either star. We conclude that the excited-state OH emission in AU Gem is either a transient phenomenon (such as for NML Cyg outlined below), or possibly an artifact in the data, and that the excited state OH emission in NML Cyg was generated by an episode of enhanced shock between the stellar mass-loss and an outflow of the Cyg OB2 association. With these single exceptions, it therefore appears that excited-state OH emission indeed should not be predicted nor observable in evolved stars as part of their normal structure or evolution.Comment: ApJ Letter, accepted, 4 pages, 2 figure