Characterization of the Hamamatsu R11265-103-M64 multi-anode photomultiplier tube

The aim of this paper is to fully characterize the new multi-anode photomultiplier tube R11265-103-M64, produced by Hamamatsu. Its high effective active area (77%), its pixel size, the low dark signal rate and the capability to detect single photon signals make this tube suitable for an application in high energy physics, such as for RICH detectors. Four tubes and two different bias voltage dividers have been tested. The results of a standard characterization of the gain and the anode uniformity, the dark signal rate, the cross-talk and the device behaviour as a function of temperature have been studied. The behaviour of the tube is studied in a longitudinal magnetic field up to 100 Gauss. Shields made of a high permeability material are also investigated. The deterioration of the device performance due to long time operation at intense light exposure is studied. A quantitative analysis of the variation of the gain and the dark signals rate due to the aging is described.Comment: 22 page

Proposed Method for the Verification of the LHC Bus Bar Splices during Commissioning at Cryogenic Conditions

The commissioning of the Large Hadron Collider at CERN includes the powering of about 1600 superconducting electrical circuits to currents ranging from 55 A to 11.8 kA. A large number of splices (over 70'000) are present at the magnet interconnects, which can only be validated with current at cryogenic conditions. This paper discusses the thermal effects related to possible faulty splices during the powering of the circuits. The calculations of the quench and detection currents, as well as the hot spot temperatures, are described. The heat transfer model with the surrounding coolant and the current profiles inside the splices are presented. This study is completed with a sensitivity analysis on the hot spot temperature with respect to the model parameters. Finally, the implications with respect to the powering ramps and parameters to be applied during the first powering are discussed

Heavy Quark Parameters and Vcb from Spectral Moments in Semileptonic B Decays

We extract the heavy quark masses and non-perturbative parameters from the Delphi preliminary measurements of the first three moments of the charged lepton energy and hadronic mass distributions in semileptonic B decays, using a multi-parameter fit. We adopt two formalisms, one of which does not rely on a 1/mc expansion and makes use of running quark masses. The data are consistent and the level of accuracy of the experimental inputs largely determines the present sensitivity. The results allow to improve on the uncertainty in the extraction of Vcb.Comment: 13 pages, 2 figure

On the Use of Wavelet Transform for Quench Precursors Characterisation in the LHC Superconducting Dipole Magnets

Premature training quenches are caused by transient energy released within the magnet coil while it is energized. Signals recorded across the so-called quench antenna carry information about these disturbances. A new method for identifying and characterizing those events is proposed, which applies the wavelet transform approach to the recorded signals. Such an approach takes into account the time of occurrence as well as frequency content of the events. The choice of the optimal mother wavelet is discussed, and the results obtained from the application of the method to actual signals are given. The criteria to recognize the interesting events are presented as well as the methodology to classify their global behavior

Subfractionation of human very low density lipoproteins by heparin-Sepharose affinity chromatography.

Very low density lipoproteins obtained from normolipidemic subjects were fractionated into subclasses by means of affinity chromatography on a heparin-Sepharose column in the presence of MnCl2. The four subfractions eluted at 0.05, 0.12, 0.20, and 0.38 M NaCl and they differed in chemical composition and apoprotein pattern. The relative amounts of apoB and apoE in subfractions increased with increasing concentrations of the NaCl eluant. Modification of the arginyl residues with 1-2 cyclohexadione demonstrated that arginine plays an important role in determining the elution pattern of VLDL. In vitro studies indicated that only fractions eluted at 0.2 and 0.5 M NaCl compete with LDL for cellular receptors. These data suggest that the various subfractions may represent VLDL at different stages of catabolism

Rapid Cortisol and Testosterone Responses to Sex-Linked Stressors: Implications for the Tend-and-Befriend Hypothesis

Current evolutionary theories regarding the nature of hormonal responses to a variety of salient social stimuli are incomplete in yielding evidentiary support for their assertions. This study offers more nuanced evidence for the Tend-and- Befriend model of sex differences in responses to social stimuli. Participants were randomly assigned to a mortality salience prime or a control condition prior to viewing a video of an out-group threat or a video of infants crying. Cortisol and testosterone responses were assessed. The results showed that in mortality salience conditions, females showed significantly higher cortisol responses to infants crying compared to males. Further, in both mortality salience and control conditions, females showed significantly higher testosterone responses to the crying infants than males. Males showed a greater testosterone response to viewing an out-group threat. Mortality salience prime did not impact testosterone responses in either sex. Results point to a more nuanced representation of hormonal responses to social stimuli and the need for multisystem measurement

Impact of the First Powering Cycles on the LHC Superconducting Dipole Coil Geometry

The impact of the first powering cycles on the LHC superconducting dipoles coil geometry has been investigated. Dedicated magnetic measurements have been performed to estimate the changes in the geometric component of the harmonics, caused by the last highest Lorentz force the coil has ever experienced. Several magnets have been powered at increasing current steps while the field quality has been measured to quantify the changes in geometry. The effect of the thermal cycles has been also considered as well as the systematic differences between measurements before and after the quench training. The reconstruction of the coil geometry variations is discussed in terms of continuous modes of deformation as well as single block displacements

Rapid Cortisol and Testosterone Responses to Sex-Linked Stressors: Implications for the Tend-and-Befriend Hypothesis

Current evolutionary theories regarding the nature of hormonal responses to a variety of salient social stimuli are incomplete in yielding evidentiary support for their assertions. This study offers more nuanced evidence for the Tend-and- Befriend model of sex differences in responses to social stimuli. Participants were randomly assigned to a mortality salience prime or a control condition prior to viewing a video of an out-group threat or a video of infants crying. Cortisol and testosterone responses were assessed. The results showed that in mortality salience conditions, females showed significantly higher cortisol responses to infants crying compared to males. Further, in both mortality salience and control conditions, females showed significantly higher testosterone responses to the crying infants than males. Males showed a greater testosterone response to viewing an out-group threat. Mortality salience prime did not impact testosterone responses in either sex. Results point to a more nuanced representation of hormonal responses to social stimuli and the need for multisystem measurement

Relationship between Self-Report and Behavioral Measures of Empathy

Conceptualizations of the construct of empathy have varied with differing methods used to examine it. Based on discordant findings in previous research on self-reported empathy and behavioral measures of empathy, the current study tested the hypothesis that self-reported and behavioral measures are significantly positively correlated with one another. Neurotypical undergraduate students completed self-report measures of empathy (Interpersonal Reactivity Index; Davis, 1980 and Empathy Quotient; Baron-Cohen & Wheelwright, 2004), a behavioral measure of empathy ("Reading the Mind in the Eyes" test-Revised; Baron-Cohen et al., 2001), temperament (Adult Temperament Questionnaire; Rothbart et al., 2000), personality (Mini-Marker Big Five; Saucier, 1994), and gender identification (Bem, 1974). Results showed that empathy self-report scales were not consistently correlated with the behavioral measure of empathy, and moderation analyses revealed significant differences between males and females on self-reported versus behavioral measures of empathy. Additional analyses indicated that empathy may also be understood in the context of other dispositional traits such as temperament. As a multidimensional construct, the study of empathy may be better understood with measures of empathy that are behaviorally based in order to correct for potential issues with self-report measures.Department of Psycholog