5,152 research outputs found
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
Improved Limits on decays to invisible final states
We establish improved upper limits on branching fractions for B0 decays to
final States 10 where the decay products are purely invisible (i.e., no
observable final state particles) and for final states where the only visible
product is a photon. Within the Standard Model, these decays have branching
fractions that are below the current experimental sensitivity, but various
models of physics beyond the Standard Model predict significant contributions
for these channels. Using 471 million BB pairs collected at the Y(4S) resonance
by the BABAR experiment at the PEP-II e+e- storage ring at the SLAC National
Accelerator Laboratory, we establish upper limits at the 90% confidence level
of 2.4x10^-5 for the branching fraction of B0-->Invisible and 1.7x10^-5 for the
branching fraction of B0-->Invisible+gammaComment: 8 pages, 3 postscript figures, submitted to Phys. Rev. D (Rapid
Communications
The CHEK2 1100delC mutation identifies families with a hereditary breast and colorectal cancer phenotype
Because of genetic heterogeneity, the identification of breast
cancer-susceptibility genes has proven to be exceedingly difficult. Here,
we define a new subset of families with breast cancer characterized by the
presence of colorectal cancer cases. The 1100delC variant of the cell
cycle checkpoint kinase CHEK2 gene was present in 18% of 55 families with
hereditary breast and colorectal cancer (HBCC) as compared with 4% of 380
families with non-HBCC (P<.001), thus providing genetic evidence for the
HBCC phenotype. The CHEK2 1100delC mutation was, however, not the major
predisposing factor for the HBCC phenotype but appeared to act in synergy
with another, as-yet-unknown susceptibility gene(s). The unequivocal
definition of the HBCC phenotype opens new avenues to search for thi
An investigation into the perception of spatial techniques used in multi-channel electroacoustic music
The paper reports on an experiment designed to examine the perception of the spatial attributes of envelopment and engulfment in spatial techniques used in multichannel electroacoustic music. Four spatial techniques were examined, they were: (i) Timbre Spatialisation [1], (ii) Spectral Splitting [2], (iii) Amplitude Point Source [3], and the proposed (iv) Dynamic Spectral Spatialisation technique. The multi-channel loudspeaker configuration consisted of 16 loudspeakers, eight horizontal and eight elevated. The experiment was design whereby the four above mentioned spatial techniques were presented in three conditions: (i) Horizontal only, (ii) Elevated only, and (iii) Horizontal and Elevated, referred to as Three Dimensional (3D), loudspeaker configurations. The experiment took place in the Spatialisation Auditory Display Environment (SpADE) at the University of Limerick and has physical attributes that conform to the ITU-R BS.1116-1 listening room standard [4]. Each participant individually undertook a listening experiment whereby they were asked to evaluate each spatial technique presented in the three conditions for perceived levels of envelopment and engulfment. A factorial analysis of variance (ANOVA) was performed on the envelopment and engulfment ratings. The results of the analysis revealed a significant main effect for spatial techniques and loudspeaker configurations for both spatial attributes. Participants rated the Dynamic Spectral Spatialisation technique highest for levels of envelopment and engulfment. The Horizontal loudspeaker configuration was rated highest for envelopment and the Elevated loudspeaker configuration was rated highest for engulfment
A Perceptual Investigation into Spatialization Techniques Used in Multichannel Electroacoustic Music for Envelopment and Engulfment
© 2017 Massachusetts Institute of Technology. Composers of electroacoustic music have developed and creatively implemented various spatialization techniques for multichannel loudspeaker setups. What is not known is which of these spatialization techniques is most effective for exploiting the extended creative possibilities available in multidimensional sound. This article discusses an experiment investigating the perception of the spatial attributes of "envelopment" and "engulfment" within a high-density loudspeaker array. The spatialization techniques used in the experiment were timbre spatialization, spectral splitting, amplitude point-source panning, and dynamic spectral subband decorrelation. Three loudspeaker setups, or spatial dimensions, were investigated: horizontal-only; elevated-only; and three-dimensional, which consisted of both horizontal and elevated loudspeaker setups. Results suggest that dynamic spectral subband decorrelation was perceived as both the most enveloping and the most engulfing technique when compared to other techniques in these experimental loudspeaker configurations. We propose that the experimental results can be successfully implemented when composing electroacoustic music to exploit the creative possibilities in a high-density loudspeaker array or in other multichannel loudspeaker configurations
Evaluating the effectiveness of a sodium butyrate feed additive for the control of Salmonella carriage in finishing pigs
This study aimed to investigate the effectiveness of commercially available sodium butyrate to control the shedding of Salmonella on two Irish pig farms with a history of high Salmonella seroprevalence. On both farms, pens (12-17 pigs/pen) were randomly assigned to a control (finisher feed without additives) or an acid treatment (the same feed supplemented with 0.03% sodium butyrate) for 24-26 days prior to slaughter. On Farm A, Salmonella shedding was reduced in the acid group compared to the control group at the end of the treatment period (30% vs. 57% probability of detecting Salmonella in faeces, respectively; p\u3c0.05). However no effect of treatment was observed on Farm B, which could perhaps be explained by a concomitant infection by Lawsonia intracellularis. No significant differences in Salmonella recovery rates were observed from caecal digesta or ileocaecal/mesenteric lymph nodes collected at slaughter in either of the trials. Furthermore, feed intake, weight gain and feed conversion efficiency did not differ significantly between control and treatment groups on either farm
Exclusive Measurements of b -> s gamma Transition Rate and Photon Energy Spectrum
We use 429 fb of collision data collected at the
resonance with the BABAR detector to measure the radiative
transition rate of with a sum of 38 exclusive final
states. The inclusive branching fraction with a minimum photon energy of 1.9
GeV is found to be where the first uncertainty is statistical and the
second is systematic. We also measure the first and second moments of the
photon energy spectrum and extract the best fit values for the heavy-quark
parameters, and , in the kinetic and shape function
models.Comment: 18 pages, 14 pdf figures, submitted to Phys. Rev.
GENETIC COUNSELOR UTILIZATION AND INTERPRETATION OF SOMATIC TUMOR TESTING IN EVALUATION FOR LYNCH SYNDROME
Lynch syndrome (LS) is a hereditary cancer predisposition syndrome characterized by increased risk for colorectal and uterine cancers. Individuals with pathogenic variants in the mismatch repair (MMR) genes (MLH1, MSH2/EPCAM, MSH6, PMS2) are diagnosed with LS and subsequently recommended to proceed with high risk screening protocols to increase prevention and early detection of LS-related cancers. Various tumor studies can help identify those at high risk for LS, but sometimes create uncertainty with discordant screening and germline results, leading to unexplained mismatch repair deficiency (UMMRD). Somatic testing of the MMR genes has created opportunities for resolving UMMRD, thus clarifying LS status and ensuring appropriate cancer surveillance. However, guidelines for such testing are currently limited. The purpose of this study was to examine current and hypothetical ordering practices of cancer genetic counselors for LS evaluation and to investigate participants’ interpretation of somatic MMR testing results. Two-hundred eligible participants were recruited through the National Society of Genetic Counselors listserv and answered questions regarding demographics, ordering practices, barriers to somatic MMR testing, theoretical patient scenarios, and need for further guidelines. Statistical analysis was done using Chi-square, Fisher exact, and Wilcoxon rank-sum tests while themes were identified from free-text responses. Most respondents did not include somatic MMR testing in the work-up for LS and did not routinely order this testing, but indicated interest in ordering this in conjunction with germline testing. The gap between preferred testing strategies and current ordering practices for somatic MMR testing may be due to reported laboratory and insurance-related barriers, particularly cost and coordination of tissue specimens. Nearly all individuals endorsed the need for additional guidelines for somatic MMR testing, which could provide support to reduce barriers, encourage insurance coverage, and allow for appropriate screening recommendations for patients and family members of those with UMMRD
Spatial effects on species persistence and implications for biodiversity
Natural ecosystems are characterized by striking diversity of form and
functions and yet exhibit deep symmetries emerging across scales of space, time
and organizational complexity. Species-area relationships and species-abundance
distributions are examples of emerging patterns irrespective of the details of
the underlying ecosystem functions. Here we present empirical and theoretical
evidence for a new macroecological pattern related to the distributions of
local species persistence times, defined as the timespans between local
colonizations and extinctions in a given geographic region. Empirical
distributions pertaining to two different taxa, breeding birds and herbaceous
plants, analyzed in a new framework that accounts for the finiteness of the
observational period, exhibit power-law scaling limited by a cut-off determined
by the rate of emergence of new species. In spite of the differences between
taxa and spatial scales of analysis, the scaling exponents are statistically
indistinguishable from each other and significantly different from those
predicted by existing models. We theoretically investigate how the scaling
features depend on the structure of the spatial interaction network and show
that the empirical scaling exponents are reproduced once a two-dimensional
isotropic texture is used, regardless of the details of the ecological
interactions. The framework developed here also allows to link the cut-off
timescale with the spatial scale of analysis, and the persistence-time
distribution to the species-area relationship. We conclude that the inherent
coherence obtained between spatial and temporal macroecological patterns points
at a seemingly general feature of the dynamical evolution of ecosystems.Comment: 5 pages, 5 figures. Supplementary materials avaliable on
http://www.pnas.org/content/108/11/434
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