267 research outputs found

    Calibration of X-ray telescope prototypes at PANTER

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    We report a ground X-ray calibration of two X-ray telescope prototypes at the PANTER X-ray Test Facility, of the Max-Planck-Institute for Extraterrestrial Physics, in Neuried, Germany. The X-ray telescope prototypes were developed by the Institute of Precision Optical Engineering (IPOE) of Tongji University, in a conical Wolter-I configuration, using thermal glass slumping technology. Prototype #1 with 3 layers and Prototype #2 with 21 layers were tested to assess the prototypes' on-axis imaging performance. The measurement of Prototype #1 indicates a Half Power Diameter (HPD) of 82" at 1.49 keV. As for Prototype #2, we performed more comprehensive measurements of on-axis angular resolution and effective area at several energies ranging from 0.5-10 keV. The HPD and effective area are 111" and 39 cm^2 at 1.49 keV, respectively, at which energy the on-axis performance of the prototypes is our greatest concern.Comment: 11 pages, 9 figure

    Hydrotherapy as a recovery strategy after exercise: a pragmatic controlled trial

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    Trial registration ClinicalTrials.gov Identifier: NCT01765387Background Our aim was to evaluate the recovery effects of hydrotherapy after aerobic exercise in cardiovascular, performance and perceived fatigue. Methods A pragmatic controlled repeated measures; single-blind trial was conducted. Thirty-four recreational sportspeople visited a Sport-Centre and were assigned to a Hydrotherapy group (experimental) or rest in a bed (control) after completing a spinning session. Main outcomes measures including blood pressure, heart rate, handgrip strength, vertical jump, self-perceived fatigue, and body temperature were assessed at baseline, immediately post-exercise and post-recovery. The hypothesis of interest was the session*time interaction. Results The analysis revealed significant session*time interactions for diastolic blood pressure (P=0.031), heart rate (P=0.041), self perceived fatigue (P=0.046), and body temperature (P=0.001); but not for vertical jump (P=0.437), handgrip (P=0.845) or systolic blood pressure (P=0.266). Post-hoc analysis revealed that hydrotherapy resulted in recovered heart rate and diastolic blood pressure similar to baseline values after the spinning session. Further, hydrotherapy resulted in decreased self-perceived fatigue after the spinning session. Conclusions Our results support that hydrotherapy is an adequate strategy to facilitate cardiovascular recovers and perceived fatigue, but not strength, after spinning exercise

    Vestibular signal processing in a subject with somatosensory deafferentation: The case of sitting posture

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    <p>Abstract</p> <p>Background</p> <p>The vestibular system of the inner ear provides information about head translation/rotation in space and about the orientation of the head with respect to the gravitoinertial vector. It also largely contributes to the control of posture through vestibulospinal pathways. Testing an individual severely deprived of somatosensory information below the nose, we investigated if equilibrium can be maintained while seated on the sole basis of this information.</p> <p>Results</p> <p>Although she was unstable, the deafferented subject (DS) was able to remain seated with the eyes closed in the absence of feet, arm and back supports. However, with the head unconsciously rotated towards the left or right shoulder, the DS's instability markedly increased. Small electrical stimulations of the vestibular apparatus produced large body tilts in the DS contrary to control subjects who did not show clear postural responses to the stimulations.</p> <p>Conclusion</p> <p>The results of the present experiment show that in the lack of vision and somatosensory information, vestibular signal processing allows the maintenance of an active sitting posture (i.e. without back or side rests). When head orientation changes with respect to the trunk, in the absence of vision, the lack of cervical information prevents the transformation of the head-centered vestibular information into a trunk-centered frame of reference of body motion. For the normal subjects, this latter frame of reference enables proper postural adjustments through vestibular signal processing, irrespectively of the orientation of the head with respect to the trunk.</p

    The neurogenic effects of exogenous neuropeptide Y: early molecular events and long-lasting effects in the hippocampus of trimethyltin-treated rats.

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    Modulation of endogenous neurogenesis is regarded as a promising challenge in neuroprotection. In the rat model of hippocampal neurodegeneration obtained by Trimethyltin (TMT) administration (8 mg/kg), characterised by selective pyramidal cell loss, enhanced neurogenesis, seizures and cognitive impairment, we previously demonstrated a proliferative role of exogenous neuropeptide Y (NPY), on dentate progenitors in the early phases of neurodegeneration. To investigate the functional integration of newly-born neurons, here we studied in adult rats the long-term effects of intracerebroventricular administration of NPY (2 \ub5g/2 \ub5l, 4 days after TMT-treatment), which plays an adjuvant role in neurodegeneration and epilepsy. Our results indicate that 30 days after NPY administration the number of new neurons was still higher in TMT+NPY-treated rats than in control+saline group. As a functional correlate of the integration of new neurons into the hippocampal network, long-term potentiation recorded in Dentate Gyrus (DG) in the absence of GABAA receptor blockade was higher in the TMT+NPY-treated group than in all other groups. Furthermore, qPCR analysis of Kruppel-like factor 9, a transcription factor essential for late-phase maturation of neurons in the DG, and of the cyclin-dependent kinase 5, critically involved in the maturation and dendrite extension of newly-born neurons, revealed a significant up-regulation of both genes in TMT+NPY-treated rats compared with all other groups. To explore the early molecular events activated by NPY administration, the Sonic Hedgehog (Shh) signalling pathway, which participates in the maintenance of the neurogenic hippocampal niche, was evaluated by qPCR 1, 3 and 5 days after NPY-treatment. An early significant up-regulation of Shh expression was detected in TMT+NPY-treated rats compared with all other groups, associated with a modulation of downstream genes. Our data indicate that the neurogenic effect of NPY administration during TMT-induced neurodegeneration involves early Shh pathway activation and results in a functional integration of newly-generated neurons into the local circuit

    Production of Single W Bosons at LEP

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    We report on the observation of single W boson production in a data sample collected by the L3 detector at LEP2. The signal consists of large missing energy final states with a single energetic lepton or two hadronic jets. The cross-section is measured to be 0.61−0.33+0.43±0.05  pb0.61^{+0.43}_{-0.33} \pm 0.05 \; \rm{pb} at the centre of mass energy \sqrt{s}=172 \GeV{}, consistent with the Standard Model expectation. From this measurement the following limits on the anomalous Îł\gammaWW gauge couplings are derived at 95\% CL: −3.6ΔÎșÎł1.5\rm -3.6 \Delta \kappa_\gamma 1.5 and −3.6λγ3.6\rm -3.6 \lambda_\gamma 3.6

    Search for neutral B meson decays to two charged leptons

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    The decays Bd0, Bs0→e+e−, Ό+Ό−, e±Ό∓\mathrm{B_d^0,\,B_s^0 \rightarrow e^+e^-,\,\mu^+\mu^-,\, e^\pm\mu^\mp} are searched for in 3.5 million hadronic Z{\mathrm{Z}} events, which constitute the full LEP I data sample collected by the L3 detector. No signals are observed, therefore upper limits at the 90\%(95\%) confidence levels are set on the following branching fractions: % \begin{center}% {\setlength{\tabcolsep}{2pt} \begin{tabular}{lccccclcccc}% % Br(Bd0→e+e−)({\mathrm{B_d^0 \rightarrow {\mathrm{e^+e^-}}}}) & << & 1.4(1.8)1.4(1.8) & ×\times & 10−5 10^{-5}; & \hspace*{5mm} & Br(Bs0→e+e−)({\mathrm{B_s^0 \rightarrow {\mathrm{e^+e^-}}}}) & << & 5.4(7.0)5.4(7.0) & ×\times & 10−5 10^{-5}; \\% Br(Bd0→Ό+Ό−)({\mathrm{B_d^0 \rightarrow \mu^+\mu^-}}) & << & 1.0(1.4)1.0(1.4) & ×\times & 10−5 10^{-5}; & \hspace*{5mm} & Br(Bs0→Ό+Ό−)({\mathrm{B_s^0 \rightarrow \mu^+\mu^-}}) & << & 3.8(5.1)3.8(5.1) & ×\times & 10−5 10^{-5}; \\% Br(Bd0→e±Ό∓)({\mathrm{B_d^0 \rightarrow {\mathrm{e^\pm\mu^\mp}}}}) & << & 1.6(2.0)1.6(2.0) & ×\times & 10−5 10^{-5}; & \hspace*{5mm} & Br(Bs0→e±Ό∓)({\mathrm{B_s^0 \rightarrow {\mathrm{e^\pm\mu^\mp}}}}) & << & 4.1(5.3)4.1(5.3) & ×\times & 10−5 10^{-5}. \\% % \end{tabular}% } \end{center}% % The results for Bs0→e+e−{\mathrm{B_s^0\rightarrow{\mathrm{e^+e^-}}}} and Bs0→e±Ό∓{\mathrm{B_s^0 \rightarrow {\mathrm{e^\pm\mu^\mp}}}} are the first limits set on these decay modes

    Measurement of energetic single-photon production at LEP

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    Search for neutral charmless B decays at LEP

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    A search for rare charmless decays of \Bd and \Bs mesons has been performed in the exclusive channels \Bd_{(\mathrm s)}\ra\eta\eta, \Bd_{(\mathrm s)}\ra\eta\pio and \Bd_{(\mathrm s)}\ra\pio\pio. The data sample consisted of three million hadronic \Zo decays collected by the L3 experiment at LEP from 1991 through 1994. No candidate event has been observed and the following upper limits at 90\% confidence level on the branching ratios have been set \begin{displaymath} \mathrm{Br}(\Bd\ra\eta\eta)<4.1\times 10^{-4},\,\, \mathrm{Br}(\Bs\ra\eta\eta)<1.5\times 10^{-3},\,\, \end{displaymath} \begin{displaymath} \mathrm{Br}(\Bd\ra\eta\pio)<2.5\times 10^{-4},\,\, \mathrm{Br}(\Bs\ra\eta\pio)<1.0\times 10^{-3},\,\, \end{displaymath} \begin{displaymath} \mathrm{Br}(\Bd\ra\pio\pio)<6.0\times 10^{-5},\,\, \mathrm{Br}(\Bs\ra\pio\pio)<2.1\times 10^{-4}. \end{displaymath} These are the first experimental limits on \Bd\ra\eta\eta and on the \Bs neutral charmless modes

    B∗^{*} production in Z decays at LEP

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    Study of the Weak Charged Hadronic Current in b Decays

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    Charged and neutral particle multiplicities of jets associated with identified semileptonic and hadronic b decays are studied. The observed differences between these jets are used to determine the inclusive properties of the weak charged hadronic current. The average charged particle multiplicity of the weak charged hadronic current in b decays is measured for the first time to be 2.69±\pm0.07(stat.)±\pm0.14(syst.). This result is in good agreement with the JETSET hadronization model of the weak charged hadronic current if 40±\pm17\% of the produced mesons are light--flavored tensor (L=1) mesons. This level of tensor meson production is consistent with the measurement of the π0\pi^0 multiplicity in the weak charged hadronic current in b decays. \end{abstract
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