294 research outputs found
Carpal Tunnel Syndrome in Patient on long Term Hemodialysis - a Case Report
Pain in hands is a common complaint in patients of end-stage renal disease on long term hemodialysis. This pain can arise from various different etiological factors. We present one such case of 56 years old lady who suffered from pain in the hand due to carpal tunnel syndrome on the side with angioaccess. Carpal tunnel was released by open surgical technique resulting in symptomatic relief of the patient
Association between Intraoperative Bactibilia and Postoperative Septic Complications in Biliary Tract Surgery
Background: The present study intended to clarify the role of biliary bacteria in the development of postoperative septic complications in patients undergoing biliary operations and need for antibiotic prophylaxis.Patient and methods: A total of 121 patients with various biliary tract diseases underwent various surgical interventions. The relation between contaminated ductal bile and postoperative septic complications was analyzed prospectively.Results: 42/121 patients were bile culture positive (B+) while 79/121 patients were bile culture negative (B-).14 patients in B (+) group developed septic complications compared to only 3 patients in B (-) group (P = 0.0001). In B (+) group, bacteria found in ductal bile were also detected in infected sites of 85% of patients with septic complications. In B (+) group postoperative antibiotic modification significantly (p=0.001) reduced infectious complications.Conclusion: Infected bile plays a critical role in development of post operative septic complications. Hence patients with risk factors for bactibilia should receive prophylactic antibiotics covering endogenous gram negative organisms which should be modified in postoperative phase according to the results of sensitivity. However this issue requires further investigations by studies conducted on similar lines
The effects of discreteness of galactic cosmic rays sources
Most studies of GeV Galactic Cosmic Rays (GCR) nuclei assume a steady
state/continuous distribution for the sources of cosmic rays, but this
distribution is actually discrete in time and in space. The current progress in
our understanding of cosmic ray physics (acceleration, propagation), the
required consistency in explaining several GCRs manifestation (nuclei,
,...) as well as the precision of present and future space missions
(e.g. INTEGRAL, AMS, AGILE, GLAST) point towards the necessity to go beyond
this approximation. A steady state semi-analytical model that describes well
many nuclei data has been developed in the past years based on this
approximation, as well as others. We wish to extend it to a time dependent
version, including discrete sources. As a first step, the validity of several
approximations of the model we use are checked to validate the approach: i) the
effect of the radial variation of the interstellar gas density is inspected and
ii) the effect of a specific modeling for the galactic wind (linear vs
constant) is discussed. In a second step, the approximation of using continuous
sources in space is considered. This is completed by a study of time
discreteness through the time-dependent version of the propagation equation. A
new analytical solution of this equation for instantaneous point-like sources,
including the effect of escape, galactic wind and spallation, is presented.
Application of time and space discretness to definite propagation conditions
and realistic distributions of sources will be presented in a future paper.Comment: final version, 8 figures, accepted in ApJ. A misprint in fig 8 labels
has been correcte
Probing the mass function of halo dark matter via microlensing
The simplest interpretation of the microlensing events observed towards the
Large Magellanic Clouds is that approximately half of the mass of the Milky Way
halo is in the form of MAssive Compact Halo Objects with . It is not possible, due to limits from star counts and chemical
abundance arguments, for faint stars or white dwarves to comprise such a large
fraction of the halo mass. This leads to the consideration of more exotic lens
candidates, such as primordial black holes, or alternative lens locations. If
the lenses are located in the halo of the Milky Way, then constraining their
mass function will shed light on their nature. Using the current microlensing
data we find, for four halo models, the best fit parameters for delta-function,
primordial black hole and various power law mass functions. The best fit
primordial black hole mass functions, despite having significant finite width,
have likelihoods which are similar to, and for one particular halo model
greater than, those of the best fit delta functions . We then use Monte Carlo
simulations to investigate the number of microlensing events necessary to
determine whether the MACHO mass function has significant finite width. If the
correct halo model is known, then 500 microlensing events will be
sufficient, and will also allow determination of the mass function parameters
to .Comment: 28 pages including 14 figures, version to appear in ApJ, minor
changes to discussio
On the Sunyaev-Zel'dovich effect from dark matter annihilation or decay in galaxy clusters
We revisit the prospects for detecting the Sunyaev Zel'dovich (SZ) effect
induced by dark matter (DM) annihilation or decay. We show that with standard
(or even extreme) assumptions for DM properties, the optical depth associated
with relativistic electrons injected from DM annihilation or decay is much
smaller than that associated with thermal electrons, when averaged over the
angular resolution of current and future experiments. For example, we find:
(depending on the assumptions) for \mchi
= 1 GeV and a density profile for a template cluster
located at 50 Mpc and observed within an angular resolution of , compared
to . This, together with a full spectral
analysis, enables us to demonstrate that, for a template cluster with generic
properties, the SZ effect due to DM annihilation or decay is far below the
sensitivity of the Planck satellite. This is at variance with previous claims
regarding heavier annihilating DM particles. Should DM be made of lighter
particles, the current constraints from 511 keV observations on the
annihilation cross section or decay rate still prevent a detectable SZ effect.
Finally, we show that spatial diffusion sets a core of a few kpc in the
electron distribution, even for very cuspy DM profiles, such that improving the
angular resolution of the instrument, e.g. with ALMA, does not necessarily
improve the detection potential. We provide useful analytical formulae
parameterized in terms of the DM mass, decay rate or annihilation cross section
and DM halo features, that allow quick estimates of the SZ effect induced by
any given candidate and any DM halo profile.Comment: 27 p, 6 figs, additional section on spatial diffusion effects.
Accepted for publication in JCA
Status of cosmic-ray antideuteron searches
The precise measurement of cosmic-ray antiparticles serves as important means
for identifying the nature of dark matter. Recent years showed that identifying
the nature of dark matter with cosmic-ray positrons and higher energy
antiprotons is difficult, and has lead to a significantly increased interest in
cosmic-ray antideuteron searches. Antideuterons may also be generated in dark
matter annihilations or decays, offering a potential breakthrough in unexplored
phase space for dark matter. Low-energy antideuterons are an important approach
because the flux from dark matter interactions exceeds the background flux by
more than two orders of magnitude in the low-energy range for a wide variety of
models. This review is based on the "dbar14 - dedicated cosmic-ray antideuteron
workshop", which brought together theorists and experimentalists in the field
to discuss the current status, perspectives, and challenges for cosmic-ray
antideuteron searches and discusses the motivation for antideuteron searches,
the theoretical and experimental uncertainties of antideuteron production and
propagation in our Galaxy, as well as give an experimental cosmic-ray
antideuteron search status update. This report is a condensed summary of the
article "Review of the theoretical and experimental status of dark matter
identification with cosmic-ray antideuteron" (arXiv:1505.07785).Comment: 9 pages, 4 figures, ICRC 2015 proceeding
Z', new fermions and flavor changing processes, constraints on E models from --> eee
We study a new class of flavor changing interactions, which can arise in
models based on extended gauge groups (rank 4) when new charged fermions are
present together with a new neutral gauge boson. We discuss the cases in which
the flavor changing couplings in the new neutral current coupled to the
are theoretically expected to be large, implying that the observed
suppression of neutral flavor changing transitions must be provided by heavy
masses together with small - mixing angles.
Concentrating on E models, we show how the tight experimental limit on implies serious constraints on the mass and mixing
angle. We conclude that if the value of the flavor changing parameters is
assumed to lie in a theoretically natural range, in most cases the presence of
a much lighter than 1 TeV is unlikely.Comment: plain tex, 22 pages + 2 pages figures in PostScript (appended after
`\bye'), UM-TH 92-1
Radiação solar disponível em Manaus (AM) e sua relação com a duração do brilho solar
Measurements of global solar radiation at ground level (Qg), were made at INPA, Manaus-AM, using a Eppley pyranometer during 1977 to 1979. The correlation between (Qg) and (QO) has the following relationship Qg = QO (0,26 + 0,49 n/N). Daily values of radiation and insolation for the study period are also presented. The mean daily radiation was 373 cal. cm-2 day-1 for this period.Medidas de radiação solar global, ao nível do solo (Og), foram realizadas na sede do INPA em Manaus-AM, com um piranômetro Eppley no período de 1977 a 1979. Foi estudada a correlação entre a radiação solar global e a insolação. O resultado obtido foi Og = Qo (0,26 + 0,49 n/N). São apresentados também os valores diários de radiação e de insolação. O valor médio diário de radiação solar encontrado para o período foi de 373 cal. cm-2 dia-1
Production of antimatter in the galaxy
The astronomical dark matter could be made of weakly interacting massive
species whose mutual annihilations should produce antimatter particles and
distortions in the corresponding energy spectra. The propagation of cosmic rays
inside the Milky Way plays a crucial role and is briefly presented. The
uncertainties in its description lead to considerable variations in the
predicted primary fluxes. This point is illustrated with antiprotons. Finally,
the various forthcoming projects are rapidly reviewed with their potential
reach.Comment: Invited talk at the TAUP 2005 Conference in Zaragoza (Spain
An automated 3D-printed perfusion bioreactor combinable with pulsed electromagnetic field stimulators for bone tissue investigations
In bone tissue engineering research, bioreactors designed for replicating the main features of the complex native environment represent powerful investigation tools. Moreover, when equipped with automation, their use allows reducing user intervention and dependence, increasing reproducibility and the overall quality of the culture process. In this study, an automated uni-/bi-directional perfusion bioreactor combinable with pulsed electromagnetic field (PEMF) stimulation for culturing 3D bone tissue models is proposed. A user-friendly control unit automates the perfusion, minimizing the user dependency. Computational fluid dynamics simulations supported the culture chamber design and allowed the estimation of the shear stress values within the construct. Electromagnetic field simulations demonstrated that, in case of combination with a PEMF stimulator, the construct can be exposed to uniform magnetic fields. Preliminary biological tests on 3D bone tissue models showed that perfusion promotes the release of the early differentiation marker alkaline phosphatase. The histological analysis confirmed that perfusion favors cells to deposit more extracellular matrix (ECM) with respect to the static culture and revealed that bi-directional perfusion better promotes ECM deposition across the construct with respect to uni-directional perfusion. Lastly, the Real-time PCR results of 3D bone tissue models cultured under bi-directional perfusion without and with PEMF stimulation revealed that the only perfusion induced a similar to 40-fold up-regulation of the expression of the osteogenic gene collagen type I with respect to the static control, while a similar to 80-fold up-regulation was measured when perfusion was combined with PEMF stimulation, indicating a positive synergic proosteogenic effect of combined physical stimulations
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