86 research outputs found
THz and Raman Spectroscopy in Steroid Chemistry
The terahertz time-domain and Raman spectra of steroids in the region of 0.1-3.5 THz have been measured. Steroids have several intense and specific absorption features in the THz frequency region. The features are uniquely determined by a hormone structure. This allows us to analyze steroids in complex samples such as pharmaceuticals, foodstuffs and biological fluids, and in process of the pharmacological and chemical synthesis
A method of improving clinical work with patients with peptic ulcer of stomach and duodenum
Objective: identification of risk groups for development of complications of ulcerous disease of stomach and duodenum.Material and Methods. We used data from the official statistical reports of the health Committee of the city of Saratov and the logs of incoming and departures/deaths of patients in the surgical and gastroenterology clinics of the city (1976-2006). The parameters of the prevalence of gastric ulcer and duodenal ulcer and its complications in the population of different age groups are analyzed. Linear regression analysis, odds ratio, and analysis of the speed characteristics of the dynamics of the studied parameters in time (mean, minimum, maximum speed, range of the dynamics of the studied parameters, the number of changes in the sign of the speed of change in the prevalence of the studied parameters) were applied. Results. It was found that the probability of complications of the disease is higher among those age groups, which are characterized by a frequent change in the sign of the rate of change in the prevalence of the pathology. The necessity of age accounting in stratification of the risk of complications of gastric ulcer and duodenal ulcer and the multiplicity of medical observation of persons of different ages with this pathology, taking into account the analytical parameters of the disease. Conclusion. The scheme of determining the multiplicity of dispensary examinations of patients with gastric ulcer and duodenal ulcer is proposed.</div
Theory of charge transport in diffusive normal metal / unconventional singlet superconductor contacts
We analyze the transport properties of contacts between unconventional
superconductor and normal diffusive metal in the framework of the extended
circuit theory. We obtain a general boundary condition for the Keldysh-Nambu
Green's functions at the interface that is valid for arbitrary transparencies
of the interface. This allows us to investigate the voltage-dependent
conductance (conductance spectrum) of a diffusive normal metal (DN)/
unconventional singlet superconductor junction in both ballistic and diffusive
cases. For d-wave superconductor, we calculate conductance spectra numerically
for different orientations of the junctions, resistances, Thouless energies in
DN, and transparencies of the interface. We demonstrate that conductance
spectra exhibit a variety of features including a -shaped gap-like
structure, zero bias conductance peak (ZBCP) and zero bias conductance dip
(ZBCD). We show that two distinct mechanisms: (i) coherent Andreev reflection
(CAR) in DN and (ii) formation of midgap Andreev bound state (MABS) at the
interface of d-wave superconductors, are responsible for ZBCP, their relative
importance being dependent on the angle between the interface normal
and the crystal axis of d-wave superconductors. For , the ZBCP is due
to CAR in the junctions of low transparency with small Thouless energies, this
is similar to the case of diffusive normal metal / insulator /s-wave
superconductor junctions. With increase of from zero to , the
MABS contribution to ZBCP becomes more prominent and the effect of CAR is
gradually suppressed. Such complex spectral features shall be observable in
conductance spectra of realistic high- junctions at very low temperature
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at TeV
The inclusive transverse momentum () distributions of primary
charged particles are measured in the pseudo-rapidity range as a
function of event centrality in Pb-Pb collisions at
TeV with ALICE at the LHC. The data are presented in the range
GeV/ for nine centrality intervals from 70-80% to 0-5%.
The Pb-Pb spectra are presented in terms of the nuclear modification factor
using a pp reference spectrum measured at the same collision
energy. We observe that the suppression of high- particles strongly
depends on event centrality. In central collisions (0-5%) the yield is most
suppressed with at -7 GeV/. Above
GeV/, there is a significant rise in the nuclear modification
factor, which reaches for GeV/. In
peripheral collisions (70-80%), the suppression is weaker with almost independently of . The measured nuclear
modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/284
Measurement of charm production at central rapidity in proton-proton collisions at TeV
The -differential production cross sections of the prompt (B
feed-down subtracted) charmed mesons D, D, and D in the rapidity
range , and for transverse momentum GeV/, were
measured in proton-proton collisions at TeV with the ALICE
detector at the Large Hadron Collider. The analysis exploited the hadronic
decays DK, DK, DD, and their charge conjugates, and was performed on a
nb event sample collected in 2011 with a
minimum-bias trigger. The total charm production cross section at TeV and at 7 TeV was evaluated by extrapolating to the full phase space
the -differential production cross sections at TeV
and our previous measurements at TeV. The results were compared
to existing measurements and to perturbative-QCD calculations. The fraction of
cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/307
Two-pion Bose-Einstein correlations in central Pb-Pb collisions at = 2.76 TeV
The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb
collisions at TeV at the Large Hadron Collider is
presented. We observe a growing trend with energy now not only for the
longitudinal and the outward but also for the sideward pion source radius. The
pion homogeneity volume and the decoupling time are significantly larger than
those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/388
Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at TeV
Inclusive transverse momentum spectra of primary charged particles in Pb-Pb
collisions at = 2.76 TeV have been measured by the ALICE
Collaboration at the LHC. The data are presented for central and peripheral
collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross
section. The measured charged particle spectra in and GeV/ are compared to the expectation in pp collisions at the same
, scaled by the number of underlying nucleon-nucleon
collisions. The comparison is expressed in terms of the nuclear modification
factor . The result indicates only weak medium effects ( 0.7) in peripheral collisions. In central collisions,
reaches a minimum of about 0.14 at -7GeV/ and increases
significantly at larger . The measured suppression of high- particles is stronger than that observed at lower collision energies,
indicating that a very dense medium is formed in central Pb-Pb collisions at
the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98
Particle-yield modification in jet-like azimuthal di-hadron correlations in Pb-Pb collisions at = 2.76 TeV
The yield of charged particles associated with high- trigger
particles ( GeV/) is measured with the ALICE detector in
Pb-Pb collisions at = 2.76 TeV relative to proton-proton
collisions at the same energy. The conditional per-trigger yields are extracted
from the narrow jet-like correlation peaks in azimuthal di-hadron correlations.
In the 5% most central collisions, we observe that the yield of associated
charged particles with transverse momenta GeV/ on the
away-side drops to about 60% of that observed in pp collisions, while on the
near-side a moderate enhancement of 20-30% is found.Comment: 15 pages, 2 captioned figures, 1 table, authors from page 10,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/350
Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy
During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with the Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all three observations: the UV emission-line flux decrease, the soft-excess increase, and the emission-line anomaly
- …