719 research outputs found
Prognostic significance of organ dysfunction in cats with polytrauma
Polytrauma is a common emergency condition in small animals and is frequently associated with higher morbidity and mortality rates compared to minor trauma. Multiple Organ Dysfunction Syndrome (MODS) is a major complication of extensive traumatic injury, carrying a high risk of death despite intensive care treatment. Little is known about the prevalence and the prognostic impact of MODS in feline polytrauma. The current study aimed to prospectively evaluate the occurrence and the prognostic significance of organ dysfunction at admission in a population of polytraumatized cats. Cats with polytrauma requiring intensive care unit hospitalization were included and categorized according to outcome (survivors/non-survivors). Clinical and clinicopathological data, including scores of disease severity [Animal Trauma Triage Score (ATTS), APPLEfast, and APPLEfull], selected organ dysfunction and presence of MODS were evaluated upon admission, and analyzed with respect to mortality. Non-parametric statistics was performed and P < 0.05 was considered significant. Thirty-eight cats met the inclusion criteria: 8/38 (21%) had penetrating trauma, while 30/38 (79%) had blunt trauma. The overall in-hospital mortality was 37% (14/38). Cats with evidence of MODS upon admission had significantly higher frequency of death compared to cats without MODS (9/14 vs. 2/24 P = 0.0004). Hemostatic dysfunction, respiratory dysfunction, and MODS upon admission were significantly associated with mortality in the univariate logistic regression analysis (P = 0.005, P = 0.001, P = 0.001, respectively). The values of APPLEfast, APPLEfull, and ATTS were independently associated with a higher risk of death and positively correlated with the number of dysfunctional organs (P = 0.025, P = 0.004, P = 0.003, r = 0.57, P = 0.0002; r = 0.59, P = 0.0001; r = 0.55, P = 0.0003, respectively). Multiple Organ Dysfunction Syndrome is a common complication of feline polytrauma and its development is associated with increased disease severity and worse outcomes. The presence of hemostatic dysfunction and respiratory dysfunction upon admission is associated with a higher risk of death. The ATTS and the APPLE scores are useful prognostic tools for the assessment of cats with polytrauma
Data model issues in the Cherenkov Telescope Array project
The planned Cherenkov Telescope Array (CTA), a future ground-based
Very-High-Energy (VHE) gamma-ray observatory, will be the largest project of
its kind. It aims to provide an order of magnitude increase in sensitivity
compared to currently operating VHE experiments and open access to guest
observers. These features, together with the thirty years lifetime planned for
the installation, impose severe constraints on the data model currently being
developed for the project.
In this contribution we analyze the challenges faced by the CTA data model
development and present the requirements imposed to face them. While the full
data model is still not completed we show the organization of the work, status
of the design, and an overview of the prototyping efforts carried out so far.
We also show examples of specific aspects of the data model currently under
development.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
The Swift-BAT survey reveals the orbital period of three high-mass X-ray binaries
A growing number of previously hidden Galactic X-ray sources are now detected
with recent surveys performed by the Integral and Swift satellites. Most of
these new sources eluded past surveys due to their large local X-ray extinction
and consequent low soft X-ray flux. The Swift-BAT performs daily monitoring of
the sky in an energy band (15-150 keV) which is only marginally affected by
X-ray extinction, thus allowing for the search of long periodicities in the
light curve and identification of the nature of the X-ray sources. We performed
a period search using the folding technique in the Swift-BAT light curves of
three Integral sources: IGR J05007-7047, IGR J13186-6257 and IGR J17354-3255.
Their periodograms show significant peaks at 30.770.01 d, 19.9940.01
d and 8.4480.002 d, respectively. We estimate the significance of these
features from the chi squared distribution of all the trials, finding a
probability less than 1.5 that the detections occurred due to
chance. We complement our analysis with the study of their broadband X-ray
emission. We identify the periodicities with the orbital periods of the
sources. The periods are typical for the wind accretors X-ray binaries and we
support this identification showing that also their energy spectra are
compatible with an X-ray spectral emission characteristic of high-mass X-ray
binaries. The spectrum of IGR J05007-704 that resides in the Large Magellanic
Cloud, does not show any intrinsic local absorption, whereas the spectra of the
Galactic sources IGR J17354-3255 and IGR J13186-6257 may be affected by a local
absorber. The folded light curve for IGR J13186-6257 suggests a possible Be
companion star.Comment: 10 pages, 14 figures. Accepted for publication in A&
Gamma-ray observations of Cygnus X-1 above 100 MeV in the hard and soft states
We present the results of multi-year gamma-ray observations by the AGILE
satellite of the black hole binary system Cygnus X-1. In a previous
investigation we focused on gamma-ray observations of Cygnus X-1 in the hard
state during the period mid-2007/2009. Here we present the results of the
gamma-ray monitoring of Cygnus X-1 during the period 2010/mid-2012 carried out
for which includes a remarkably prolonged `soft state' phase (June 2010 -- May
2011). Previous 1--10 MeV observations of Cyg X-1 in this state hinted at a
possible existence of a non-thermal particle component with substantial
modifications of the Comptonized emission from the inner accretion disk. Our
AGILE data, averaged over the mid-2010/mid-2011 soft state of Cygnus X-1,
provide a significant upper limit for gamma-ray emission above 100 MeV of
F_soft < 20 x 10^{-8} ph/cm^2/s, excluding the existence of prominent
non-thermal emission above 100 MeV during the soft state of Cygnus X-1. We
discuss theoretical implications of our findings in the context of high-energy
emission models of black hole accretion. We also discuss possible gamma-ray
flares detected by AGILE. In addition to a previously reported episode observed
by AGILE in October 2009 during the hard state, we report a weak but important
candidate for enhanced emission which occurred at the end of June 2010
(2010-06-30 10:00 - 2010-07-02 10:00 UT) exactly in coincidence with a
hard-to-soft state transition and before an anomalous radio flare. An appendix
summarizes all previous high-energy observations and possible detections of
Cygnus X-1 above 1 MeV.Comment: 16 pages, 12 figures, 1 table, accepted for publication in Ap
A giant radio flare from Cygnus X-3 with associated Gamma-ray emission
With frequent flaring activity of its relativistic jets, Cygnus X-3 is one of
the most active microquasars and is the only Galactic black hole candidate with
confirmed high energy Gamma-ray emission, thanks to detections by Fermi/LAT and
AGILE. In 2011, Cygnus X-3 was observed to transit to a soft X-ray state, which
is known to be associated with high-energy Gamma-ray emission. We present the
results of a multi-wavelength campaign covering a quenched state, when radio
emission from Cygnus X-3 is at its weakest and the X-ray spectrum is very soft.
A giant (~ 20 Jy) optically thin radio flare marks the end of the quenched
state, accompanied by rising non-thermal hard X-rays. Fermi/LAT observations (E
>100 MeV) reveal renewed Gamma-ray activity associated with this giant radio
flare, suggesting a common origin for all non-thermal components. In addition,
current observations unambiguously show that the Gamma-ray emission is not
exclusively related to the rare giant radio flares. A 3-week period of
Gamma-ray emission is also detected when Cygnus X-3 was weakly flaring in
radio, right before transition to the radio quenched state. No Gamma rays are
observed during the ~ one-month long quenched state, when the radio flux is
weakest. Our results suggest transitions into and out of the ultrasoft X-ray
(radio quenched) state trigger Gamma-ray emission, implying a connection to the
accretion process, and also that the Gamma-ray activity is related to the level
of radio flux (and possibly shock formation), strengthening the connection to
the relativistic jets.Comment: Accepted for publication in MNRAS. 10 pages 5 figures, 1 tabl
AGILE detection of a strong gamma-ray flare from the blazar 3C 454.3
We report the first blazar detection by the AGILE satellite. AGILE detected
3C 454.3 during a period of strongly enhanced optical emission in July 2007.
AGILE observed the source with a dedicated repointing during the period 2007
July 24-30 with its two co-aligned imagers, the Gamma-Ray Imaging Detector and
the hard X-ray imager Super-AGILE sensitive in the 30 MeV-50 GeV and 18-60 keV,
respectively. Over the entire period, AGILE detected gamma-ray emission from 3C
454.3 at a significance level of 13.8- with an average flux (E100
MeV) of photons cm s. The gamma-ray
flux appears to be variable towards the end of the observation. No emission was
detected by Super-AGILE in the energy range 20-60 keV, with a 3- upper
limit of photons cm s. The gamma-ray flux
level of 3C 454.3 detected by AGILE is the highest ever detected for this
quasar and among the most intense gamma-ray fluxes ever detected from Flat
Spectrum Radio Quasars.Comment: Accepted by Astrophysical Journal Letters; 14 pages, 3 EPS Figures, 1
Tabl
Region of Excessive Flux of PeV Cosmic Rays in the Direction Toward Pulsars PSR J1840+5640 and LAT PSR J1836+5925
An analysis of arrival directions of extensive air showers (EAS) registered
with the EAS MSU and EAS-1000 prototype arrays has revealed a region of
excessive flux of PeV cosmic rays in the direction toward pulsars PSR
J1840+5640 and LAT PSR J1836+5925 at significance level up to 4.5sigma. The
first of the pulsars was discovered almost 30 years ago and is a well-studied
old radio pulsar located at the distance of 1.7pc from the Solar system. The
second pulsar belongs to a new type of pulsars, discovered by the space
gamma-ray observatory Fermi, pulsations of which are not observed in optical
and radio wavelengths but only in the gamma-ray range of energies
(gamma-ray-only pulsars). In our opinion, the existence of the region of
excessive flux of cosmic rays registered with two different arrays provides a
strong evidence that isolated pulsars can give a noticeable contribution to the
flux of Galactic cosmic rays in the PeV energy range.Comment: 14 pages; v.2: a few remarks to match a version accepted for
Astronomy Letters added. They can be found by redefining the \NEW command in
the preamble of the LaTeX fil
Cherenkov Telescope Array Data Management
Very High Energy gamma-ray astronomy with the Cherenkov Telescope Array (CTA)
is evolving towards the model of a public observatory. Handling, processing and
archiving the large amount of data generated by the CTA instruments and
delivering scientific products are some of the challenges in designing the CTA
Data Management. The participation of scientists from within CTA Consortium and
from the greater worldwide scientific community necessitates a sophisticated
scientific analysis system capable of providing unified and efficient user
access to data, software and computing resources. Data Management is designed
to respond to three main issues: (i) the treatment and flow of data from remote
telescopes; (ii) "big-data" archiving and processing; (iii) and open data
access. In this communication the overall technical design of the CTA Data
Management, current major developments and prototypes are presented.Comment: 8 pages, 2 figures, In Proceedings of the 34th International Cosmic
Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions
at arXiv:1508.0589
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