5,055 research outputs found
Probability and Statistics for Particle Physicists
Lectures presented at the 1st CERN Asia-Europe-Pacific School of High-Energy
Physics, Fukuoka, Japan, 14-27 October 2012. A pedagogical selection of topics
in probability and statistics is presented. Choice and emphasis are driven by
the author's personal experience, predominantly in the context of physics
analyses using experimental data from high-energy physics detectors.Comment: Updated version of lectures given at the First Asia-Europe-Pacific
School of High-Energy Physics, Fukuoka, Japan, 14-27 October 2012. Published
as a CERN Yellow Report (CERN-2014-001) and KEK report
(KEK-Proceedings-2013-8), K. Kawagoe and M. Mulders (eds.), 2014, p. 219.
Total 28 pages, 36 figure
The NA48 liquid krypton calorimeter description and performances
The NA48 experiment at CERN aims at making a precision study of direct CP violation in the neutral kaons, by measuring with an accuracy better than 0.02%. To achieve this goal, the experiment requires a neutral detector with fast response, high efficiency in a high-rate environment space precision, and an excellent energy resolution (1%) in the GeV range. To achieve these performances, a quasi-homogeneous Liquid Krypton calorimeter has been chosen, designed with a projective tower geometry, high transversal segmentation, and fast digital readout. The calorimeter was operative during the '97 data taking period, its performances were thoroughly studied, and found to be in agreement with design requirements. A detector description and performances analysis are here presented
The Gravitational and Electrostatic Fields Far from an Isolated Einstein-Maxwell Source
The exterior solution for an arbitrary charged, massive source, is studied as
a static deviation from the Reissner-Nordstr\o m metric. This is reduced to two
coupled ordinary differential equations for the gravitational and electrostatic
potential functions. The homogeneous equations are explicitly solved in the
particular case , obtaining a multipole expansion with radial
hypergeometric dependence for both potentials. In the limiting case of a
neutral source, the equations are shown to coincide with recent results by
Bondi and Rindler.Comment: 11 pages, revTe
Predictions of selected flavour observables within the Standard Model
This letter gathers a selection of Standard Model predictions issued from the
metrology of the CKM parameters performed by the CKMfitter group. The selection
includes purely leptonic decays of neutral and charged B, D and K mesons. In
the light of the expected measurements from the LHCb experiment, a special
attention is given to the radiative decay modes of B mesons as well as to the
B-meson mixing observables, in particular the semileptonic charge asymmetries
a^d,s_SL which have been recently investigated by the D0 experiment at
Tevatron. Constraints arising from rare kaon decays are addressed, in light of
both current results and expected performances of future rare kaon experiments.
All results have been obtained with the CKMfitter analysis package, featuring
the frequentist statistical approach and using Rfit to handle theoretical
uncertainties.Comment: 8 pages, 1 figure, 2 tables. Typos corrected and discussion of
agreement between SM and data update
Measurements of the CKM angle at the B Factories
We report measurements of time-dependent CP asymmetries related to the CKM
angle , using decays of neutral B mesons to charmonium, open
charm and in loop processes. A preliminary measurement of
time-dependent CP asymmetries in decays from the
BaBar experiment is given here.Comment: Contributed to the Proceedings of the XLI Rencontres de Moriond -
Electroweak Interactions and Unified Theory, La Thuile Italy, March 11-18,
2006. 6 page
The paradoxical effects of somatostatin on the bioactivity and production of cytotoxins derived from human peripheral blood mononuclear cells.
Somatostatin (SMS), a naturally occurring peptide is known to inhibit the production of certain protein molecules and to diminish the ability of peripheral blood mononuclear cells to proliferate. We tested the effects of three forms of SMS on the bioactivity of both lymphotoxin (LT) and tumour necrosis factor (TNF). We also tested the effects of these agents on production of cytotoxins by peripheral blood mononuclear cells. We found the 28 amino acid form of SMS significantly enhanced the bioactivity of both LT and TNF (10(-9) M concentration) when tested in mouse L cells. The 14 amino acid form of SMS enhanced LT (10(-9) M concentration) activity but not TNF activity. The first 14 amino acid form of SMS-28 (amino terminal) did not affect bioactivity of the cytotoxin. In contrast, the naturally occurring 14 amino acid form of SMS (10(-8) M concentration) significantly diminished production of cytotoxin by human peripheral blood mononuclear cells. Cytotoxin produced by the latter was shown to be a combination of both LT and TNF. Similarly after SMS exposure, the cytotoxin produced remained a mixture of LT and TNF in roughly similar proportions. It thus appears that certain forms of SMS can enhance the bioactivity of cytotoxins, but at the same time decrease the production of these cytotoxins
5-HT7 receptors in Alzheimer's disease
Even though the involvement of serotonin (5-hydroxytryptamine; 5-HT) and its receptors in Alzheimer's disease (AD) is widely accepted, data on the expression and the role of 5-HT7 receptors in AD is relatively limited. Therefore, the objective of the present work was to study the expression of serotonergic 5-HT7 receptors in postmortem samples of AD brains and correlate it with neurotransmitter levels, cognition and behavior. The study population consisted of clinically well-characterized and neuropathologically confirmed AD patients (n = 42) and age-matched control subjects (n = 18). Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) and high-performance liquid chromatography were performed on Brodmann area (BA) 7, BA10, BA22, BA24, hippocampus, amygdala, thalamus and cerebellum to measure mRNA levels of 5-HT7 receptors (HTR7), as well as the concentrations of various monoamine neurotransmitters and their metabolites. Decreased levels of HTR7 mRNA were observed in BA10. A significant association was observed between HTR7 levels in BA10 and BEHAVE-AD cluster B (hallucinations) (rs(28) = 0.444, P < 0.05). In addition, a negative correlation was observed between HTR7 levels in BA10 and both MHPG concentrations in this brain region (rs(45) = -0.311; P < 0.05), and DOPAC levels in the amygdala (rs(42) = -0.311; P < 0.05). Quite surprisingly, no association was found between HTR7 levels and cognitive status. Altogether, this study supports the notion of the involvement of 5-HT7 receptors in psychotic symptoms in AD, suggesting the interest of testing antagonist acting at this receptor to specifically treat psychotic symptoms in this illness
5-HT7 receptors in Alzheimer's disease
Even though the involvement of serotonin (5-hydroxytryptamine; 5-HT) and its receptors in Alzheimer’s disease
(AD) is widely accepted, data on the expression and the role of 5-HT7 receptors in AD is relatively limited.
Therefore, the objective of the present work was to study the expression of serotonergic 5-HT7 receptors in
postmortem samples of AD brains and correlate it with neurotransmitter levels, cognition and behavior. The
study population consisted of clinically well-characterized and neuropathologically confirmed AD patients (n =
42) and age-matched control subjects (n = 18). Reverse-transcription quantitative polymerase chain reaction
(RT-qPCR) and high-performance liquid chromatography were performed on Brodmann area (BA) 7, BA10,
BA22, BA24, hippocampus, amygdala, thalamus and cerebellum to measure mRNA levels of 5-HT7 receptors
(HTR7), as well as the concentrations of various monoamine neurotransmitters and their metabolites.
Decreased levels of HTR7 mRNA were observed in BA10. A significant association was observed between
HTR7 levels in BA10 and BEHAVE-AD cluster B (hallucinations) (rs(28) = 0.444, P < 0.05). In addition, a
negative correlation was observed between HTR7 levels in BA10 and both MHPG concentrations in this brain
region (rs(45) = -0.311; P < 0.05), and DOPAC levels in the amygdala (rs(42) = -0.311; P < 0.05). Quite sur-
prisingly, no association was found between HTR7 levels and cognitive status. Altogether, this study supports the notion of the involvement of 5-HT7 receptors in psychotic symptoms in AD, suggesting the interest of testing antagonist acting at this receptor to specifically treat psychotic symptoms in this illness
Evidence for the η_b(1S) Meson in Radiative Υ(2S) Decay
We have performed a search for the η_b(1S) meson in the radiative decay of the Υ(2S) resonance using a sample of 91.6 × 10^6 Υ(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E_γ = 609.3^(+4.6)_(-4.5)(stat)±1.9(syst) MeV, corresponding to an η_b(1S) mass of 9394.2^(+4.8)_(-4.9)(stat) ± 2.0(syst) MeV/c^2. The branching fraction for the decay Υ(2S) → γη_b(1S) is determined to be [3.9 ± 1.1(stat)^(+1.1)_(-0.9)(syst)] × 10^(-4). We find the ratio of branching fractions B[Υ(2S) → γη_b(1S)]/B[Υ(3S) → γη_b(1S)]= 0.82 ± 0.24(stat)^(+0.20)_(-0.19)(syst)
Measurement of the Branching Fraction for B- --> D0 K*-
We present a measurement of the branching fraction for the decay B- --> D0
K*- using a sample of approximately 86 million BBbar pairs collected by the
BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is
detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the
K*- through its decay to K0S pi-. We measure the branching fraction to be
B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid
Communications
- …