90 research outputs found
Infection with Trypanosoma cruzi TcII and TcI in free-ranging population of lion tamarins (Leontopithecus spp): an 11-year follow-up
Cold gas accretion in galaxies
Evidence for the accretion of cold gas in galaxies has been rapidly
accumulating in the past years. HI observations of galaxies and their
environment have brought to light new facts and phenomena which are evidence of
ongoing or recent accretion:
1) A large number of galaxies are accompanied by gas-rich dwarfs or are
surrounded by HI cloud complexes, tails and filaments. It may be regarded as
direct evidence of cold gas accretion in the local universe. It is probably the
same kind of phenomenon of material infall as the stellar streams observed in
the halos of our galaxy and M31. 2) Considerable amounts of extra-planar HI
have been found in nearby spiral galaxies. While a large fraction of this gas
is produced by galactic fountains, it is likely that a part of it is of
extragalactic origin. 3) Spirals are known to have extended and warped outer
layers of HI. It is not clear how these have formed, and how and for how long
the warps can be sustained. Gas infall has been proposed as the origin. 4) The
majority of galactic disks are lopsided in their morphology as well as in their
kinematics. Also here recent accretion has been advocated as a possible cause.
In our view, accretion takes place both through the arrival and merging of
gas-rich satellites and through gas infall from the intergalactic medium (IGM).
The infall may have observable effects on the disk such as bursts of star
formation and lopsidedness. We infer a mean ``visible'' accretion rate of cold
gas in galaxies of at least 0.2 Msol/yr. In order to reach the accretion rates
needed to sustain the observed star formation (~1 Msol/yr), additional infall
of large amounts of gas from the IGM seems to be required.Comment: To appear in Astronomy & Astrophysics Reviews. 34 pages.
Full-resolution version available at
http://www.astron.nl/~oosterlo/accretionRevie
Hemorrhagic shock and encephalopathy syndrome – the markers for an early HSES diagnosis
<p>Abstract</p> <p>Background</p> <p>The hemorrhagic shock and encephalopathy syndrome (HSES) is a devastating disease that affects young children. The outcomes of HSES patients are often fatal or manifesting severe neurological sequelae. We reviewed the markers for an early diagnosis of HSES.</p> <p>Methods</p> <p>We examined the clinical, biological and radiological findings of 8 patients (4 months to 9 years old) who met the HSES criteria.</p> <p>Results</p> <p>Although cerebral edema, disseminated intravascular coagulopathy (DIC), and multiple organ failure were seen in all 8 cases during their clinical courses, brain computed tomography (CT) scans showed normal or only slight edema in 5 patients upon admission. All 8 patients had normal platelet counts, and none were in shock. However, they all had severe metabolic acidosis, which persisted even after 3 hours (median base excess (BE), -7.6 mmol/L). And at 6 hours after admission (BE, -5.7 mmol/L) they required mechanical ventilation. Within 12 hours after admission, fluid resuscitation and vasopressor infusion for hypotension was required. Seven of the patients had elevated liver enzymes and creatine kinase (CK) upon admission. Twenty-four hours after admission, all 8 patients needed vasopressor infusion to maintain blood pressure.</p> <p>Conclusion</p> <p>CT scan, platelet count, hemoglobin level and renal function upon admission are not useful for an early diagnosis of HSES. However, the elevated liver enzymes and CK upon admission, hypotension in the early stage after admission with refractory acid-base disturbance to fluid resuscitation and vasopressor infusion are useful markers for an early HSES diagnosis and helpful to indicate starting intensive neurological treatment.</p
Cholesterol Corrects Altered Conformation of MHC-II Protein in Leishmania donovani Infected Macrophages: Implication in Therapy
Previously we reported that Kala-azar patients show progressive decrease in serum cholesterol as a function of splenic parasite burden. Splenic macrophages (MΦ) of Leishmania donovani (LD) infected mice show decrease in membrane cholesterol, while LD infected macrophages (I-MΦ) show defective T cell stimulating ability that could be corrected by liposomal delivery of cholesterol. T helper cells recognize peptide antigen in the context of
class II MHC molecule. It is known that the conformation of a large number of membrane proteins is dependent on membrane cholesterol. In this investigation we tried to understand the influence of decreased membrane cholesterol in I-MΦ on the conformation of MHC-II protein and peptide-MHC-II stability, and its bearing on the antigen specific T-cell activatio
Evaluation of the physicochemical properties of silicone- and epoxy resin-based root canal sealers
Trapping in irradiated p-on-n silicon sensors at fluences anticipated at the HL-LHC outer tracker
The degradation of signal in silicon sensors is studied under conditions expected at the CERN High-Luminosity LHC. 200 m thick n-type silicon sensors are irradiated with protons of different energies to fluences of up to neq/cm. Pulsed red laser light with a wavelength of 672 nm is used to generate electron-hole pairs in the sensors. The induced signals are used to determine the charge collection efficiencies separately for electrons and holes drifting through the sensor. The effective trapping rates are extracted by comparing the results to simulation. The electric field is simulated using Synopsys device simulation assuming two effective defects. The generation and drift of charge carriers are simulated in an independent simulation based on PixelAV. The effective trapping rates are determined from the measured charge collection efficiencies and the simulated and measured time-resolved current pulses are compared. The effective trapping rates determined for both electrons and holes are about 50% smaller than those obtained using standard extrapolations of studies at low fluences and suggests an improved tracker performance over initial expectations
Fatores associados à interrupção precoce do aleitamento materno: um estudo de coorte de nascimento em dois municípios do Recôncavo da Bahia, Brasil
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
Fatores associados à interrupção do aleitamento materno exclusivo de lactentes nascidos com baixo peso assistidos na atenção básica
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