8,372 research outputs found
Fiber R and D for the CMS HCAL
This paper documents the fiber R and D for the CMS hadron barrel calorimeter
(HCAL). The R and D includes measurements of fiber flexibility, splicing,
mirror reflectivity, relative light yield, attenuation length, radiation
effects, absolute light yield, and transverse tile uniformity. Schematics of
the hardware for each measurement are shown. These studies are done for
different diameters and kinds of multiclad fiber.Comment: 23 pages, 30 Figures 89 pages, 41 figures, corresponding author: H.
Budd, [email protected]
Relativistic Hamiltonians in many-body theories
We discuss the description of a many-body nuclear system using Hamiltonians
that contain the nucleon relativistic kinetic energy and potentials with
relativistic corrections. Through the Foldy-Wouthuysen transformation, the
field theoretical problem of interacting nucleons and mesons is mapped to an
equivalent one in terms of relativistic potentials, which are then expanded at
some order in 1/m_N. The formalism is applied to the Hartree problem in nuclear
matter, showing how the results of the relativistic mean field theory can be
recovered over a wide range of densities.Comment: 14 pages, uses REVTeX and epsfig, 3 postscript figures; a postscript
version of the paper is available by anonymous ftp at
ftp://carmen.to.infn.it/pub/depace/papers/951
HST Photometry and Keck Spectroscopy of the Rich Cluster MS1054-03: Morphologies, Butcher-Oemler Effect and the Color-Magnitude Relation at z=0.83
We present a study of 81 I selected, spectroscopically-confirmed members of
the X-ray cluster MS1054-03 at z=0.83. Redshifts and spectral types were
determined from Keck spectroscopy. Morphologies and accurate colors were
determined from a large mosaic of HST WFPC2 images in F606W and F814W.
Early-type galaxies constitute only 44% of this galaxy population. Thirty-nine
percent are spiral galaxies, and 17% are mergers. The early-type galaxies
follow a tight and well-defined color-magnitude relation, with the exception of
a few outliers. The observed scatter is 0.029 +- 0.005 magnitudes in restframe
U-B. Most of the mergers lie close to the CM relation defined by the early-type
galaxies. They are bluer by only 0.07 +- 0.02 magnitudes, and the scatter in
their colors is 0.07 +- 0.04 magnitudes. Spiral galaxies in MS1054-03 exhibit a
large range in their colors. The bluest spiral galaxies are 0.7 magnitudes
bluer than the early-type galaxies, but the majority is within +- 0.2
magnitudes of the early-type galaxy sequence. The red colors of the mergers and
the majority of the spiral galaxies are reflected in the fairly low
Butcher-Oemler blue fraction of MS1054-03: f_B=0.22 +- 0.05. The slope and
scatter of the CM relation of early-type galaxies are roughly constant with
redshift, confirming previous studies that were based on ground-based color
measurements and very limited membership information. However, the scatter in
the combined sample of early-type galaxies and mergers is twice as high as the
scatter of the early-type galaxies alone. This is a direct demonstration of the
``progenitor bias'': high redshift early-type galaxies seem to form a
homogeneous, old population because the progenitors of the youngest present-day
early-type galaxies are not included in the sample.Comment: Accepted for publication in the ApJ. At
http://astro.caltech.edu/~pgd/cm1054/ color figures can be obtaine
Long term evaluation of mental fatigue by Maastricht Questionnaire in patients with OSAS treated with CPAP
Background. Patients with obstructive sleep apnoea syndrome (OSAS) suffer from disrupted sleep. Impaired nightly sleep leads to increase physical and mental fatigue. The effect of long term continuous positive airway pressure (CPAP) on mental fatigue in OSAS patients, assessed by Maastricht Questionnaire (MQ), has not been investigated yet. Methods. In order to evaluate the role of CPAP in improving mental fatigue of patients with OSAS, we studied 35 patients (26 males, age <65 years at the time of the diagnosis) affected by OSAS, established by polysomnography (PSG). Patients were divided into two groups; 19 subjects (15 males), who refused CPAP therapy, and 16 patients (11 males) well matched for sex, age, body mass index (BMI), neck circumference, duration of follow up, and severity of disease, who had been treated with CPAP for at least two years. Results. All patients had severe OSAS with Respiratory Disturbance Index (RDI), of 48±20.9 (range 22-90) and 61.48±18.6 (range 34-101) respectively, for group one (untreated patients) and group two (CPAP treatment). In addition, all patients had severe impairment of mental fatigue and of daytime sleepiness, demonstrated by high values of MQ score (32.17±15.33 and 37.36±12.4, respectively) and Epworth Sleepiness Scale (ESS) (14.21±4.77 and 15.06±6.07 respectively). There was no statistical significant difference in the group one at baseline and after follow- up, in terms of BMI, MQ score, ESS, and RDI. In the CPAP group (group two), the patients reported a significant improvement of the quality of their mental health (MQ 37.36±12.4 vs. 16.41±9.02; p<0.0001) and sleepiness (ESS 15.06±6.07 vs. 4.13±3.93; p<0.0001) with a stable BMI. There was significant correlation between the severity of sleep apnoea, expressed as RDI, and MQ at admission compared to at the end of follow-up (r=0.4, p<0.05). Conclusions. This study demonstrates an evident deterioration of mental fatigue in patients with OSAS, directly correlated to the severity of nocturnal disorder breathing; however supports the hypothesis that long term CPAP therapy significantly improves sleepiness and mental fatigue
Constraints on a Universal IMF from UV to Near-IR Galaxy Luminosity Densities
We obtain constraints on the slope of a universal stellar initial mass
function (IMF) over a range of cosmic star-formation histories (SFH) using
z=0.1 luminosity densities in the range from 0.2 to 2.2 microns. The age-IMF
degeneracy of integrated spectra of stellar populations can be broken for the
Universe as a whole by using direct measurements of (relative) cosmic SFH from
high-redshift observations. These have only marginal dependence on
uncertainties in the IMF, whereas, fitting to local luminosity densities
depends strongly on both cosmic SFH and the IMF. We fit to these measurements
using population synthesis and find the best-fit IMF power-law slope to be
Gamma=1.15+-0.2 (0.5 < M/M_solar < 120). This slope is in good agreement with
the Salpeter IMF slope (Gamma=1.35). A strong upper limit of Gamma<1.7 is
obtained which effectively rules out the Scalo IMF due to its too low fraction
of high-mass stars. This upper limit is at the 99.7% confidence level if we
assume a closed-box chemical evolution scenario and 95% if we assume constant
solar metallicity. Fitting to the H-alpha line luminosity density, we obtain a
best-fit IMF slope in good agreement with that derived from broadband
measurements. Marginalizing over cosmic SFH and IMF slope, we obtain (95% conf.
ranges, h=1): omega_stars = 1.1-2.0 E-3 for the stellar mass density; rho_sfr =
0.7-4.1 E-2 M_solar/yr/Mpc^3 for the star-formation rate density, and; rho_L =
1.2-1.7 E+35 W/Mpc^3 for the bolometric, attenuated, stellar, luminosity
density (0.09-5 microns). Comparing this total stellar emission with an
estimate of the total dust emission implies a relatively modest average
attenuation in the UV (<=1 magnitude at 0.2 microns).Comment: 16 pages, accepted by Ap
Inelastic electron-nucleus scattering and scaling at high inelasticity
Highly inelastic electron scattering is analyzed within the context of the
unified relativistic approach previously considered in the case of quasielastic
kinematics. Inelastic relativistic Fermi gas modeling that includes the
complete inelastic spectrum - resonant, non-resonant and Deep Inelastic
Scattering - is elaborated and compared with experimental data. A
phenomenological extension of the model based on direct fits to data is also
introduced. Within both models, cross sections and response functions are
evaluated and binding energy effects are analyzed. Finally, an investigation of
the second-kind scaling behavior is also presented.Comment: 39 pages, 13 figures; formalism extended and slightly reorganized,
conclusions extended; to appear in Phys. Rev.
New Measurements of Nucleon Structure Functions from the CCFR/NuTeV Collaboration
We report on the extraction of the structure functions F_2 and Delta xF_3 =
xF_3nu-xF_3nubar from CCFR neutrino-Fe and antineutrino-Fe differential cross
sections. The extraction is performed in a physics model independent (PMI) way.
This first measurement for Delta xF_3, which is useful in testing models of
heavy charm production, is higher than current theoretical predictions. The F_2
(PMI) values measured in neutrino and muon scattering are in good agreement
with the predictions of Next to Leading Order PDFs (using massive charm
production schemes), thus resolving the long-standing discrepancy between the
two sets of data.Comment: 5 pages. Presented by Arie Bodek at the CIPNAP2000 Conference, Quebec
City, May 200
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