93 research outputs found
Analysis of the September ε-Perseid outburst in 2013
We analyse the outburst experienced by the September ε-Perseid meteor shower on 2013 September 9. As a result of our monitoring, the atmospheric trajectory of 60 multistation events observed over Spain was obtained and accurate orbital data were derived from them. On the basis of these orbits, we have tried to determine the likely parent body of this meteoroid stream by employing orbital dissimilarity criteria. In addition, the emission spectra produced by two events belonging to this meteor shower were also recorded. The analysis of these spectra has provided information about the chemical nature of their progenitor meteoroids. We also present an estimation of the tensile strength for these particles.We acknowledge support from the Spanish Ministry of Science and Innovation (projects
AYA2015-68646-P and AYA 2015-67175-P)
The 2011 October Draconids outburst. I. Orbital elements, meteoroid fluxes and 21P/Giacobini-Zinner delivered mass to Earth
On October 8th, 2011 the Earth crossed the dust trails left by comet
21P/Giacobini-Zinner during its XIX and XX century perihelion approaches with
the comet being close to perihelion. The geometric circumstances of that
encounter were thus favorable to produce a meteor storm, but the trails were
much older than in the 1933 and 1946 historical encounters. As a consequence
the 2011 October Draconid display exhibited several activity peaks with
Zenithal Hourly Rates of about 400 meteors per hour. In fact, if the display
had been not forecasted, it could have passed almost unnoticed as was strongly
attenuated for visual observers due to the Moon. This suggests that most meteor
storms of a similar nature could have passed historically unnoticed under
unfavorable weather and Moon observing conditions. The possibility of obtaining
information on the physical properties of cometary meteoroids penetrating the
atmosphere under low-geocentric velocity encounter circumstances motivated us
to set up a special observing campaign. Added to the Spanish Fireball Network
wide-field all-sky and CCD video monitoring, other high-sensitivity 1/2" black
and white CCD video cameras were attached to modified medium-field lenses for
obtaining high resolution orbital information. The trajectory, radiant, and
orbital data of 16 October Draconid meteors observed at multiple stations are
presented. The results show that the meteors appeared from a geocentric radiant
located at R.A.=263.0+-0.4 deg. and Dec.=+55.3+-0.3 deg. that is in close
agreement with the radiant predicted for the 1873-1894 and the 1900 dust
trails. The estimated mass of material from 21P/Giacobini-Zinner delivered to
Earth during the six-hours outburst was around 950+-150 kg.Comment: Manuscript in press in Monthly Notices of the Royal Astronomical
Society, submitted to MNRAS on November 16th, 2012 Accepted for publication
in MNRAS on April 28th, 2013 Manuscript Pages: 21 Tables: 8 Figures: 4
Manuscript associated: "The 2011 October Draconids outburst. II. Meteoroid
chemical abundances from fireball spectroscopy" by J.M. Madiedo is also in
press in the same journa
Multi-instrumental observations of the 2014 Ursid meteor outburst
The Ursid meteor shower is an annual shower that usually shows little activity. However, its Zenith hourly rate sometimes increases, usually either when its parent comet, 8P/Tuttle, is close to its perihelion or its aphelion. Outbursts when the comet is away from perihelion are not common and outbursts when the comet is close to aphelion are extremely rare. The most likely explanation offered to date is based on the orbital mean motion resonances. The study of the aphelion outburst of 2000 December provided a means of testing that hypothesis. A new aphelion outburst was predicted for 2014 December. The SPanish Meteor Network, in collaboration with the French Fireball Recovery and InterPlanetary Observation Network, set up a campaign to monitor this outburst and eventually retrieve orbital data that expand and confirm previous preliminary results and predictions. Despite unfavourable weather conditions over the south of Europe over the relevant time period, precise trajectories from multistation meteor data recorded over Spain were obtained, as well as orbital and radiant information for four Ursid meteors. The membership of these four meteors to the expected dust trails that were to provoke the outburst is discussed, and we characterize the origin of the outburst in the dust trail produced by the comet in the year AD 1392.Peer reviewe
Molecular mechanisms of glucocorticoids action: implications for treatment of rhinosinusitis and nasal polyposis
Intra-nasal glucocorticoids are the most effective drugs available for rhinosinusitis and nasal polyposis treatment. Their effectiveness depends on many factors and not all of them have been well recognized so far. The authors present the basic information on molecular mechanisms of glucocorticoid action, direct and indirect effects of glucocorticoids on transcription of genes encoding inflammatory mediators. They focus on recently proved nongenomic mechanisms which appear quickly, from several seconds to minutes after glucocorticoid administration and discuss clinical implications resulting from this knowledge. Discovery of nongenomic glucocorticoid actions allows for better use of these drugs in clinical practice
Life-threatening Skin Disorders Treated in the Burn Center: Impact of Health care–associated Infections on Length of Stay, Survival, and Hospital Charges
This article reviews a single burn center experience with life-threatening skin disorders, over a 10-year period. It explores the incidence of health care–associated infections and the impact on length of stay, hospital charges, and mortality
Even Better Than the Real Thing? Xenografting in Pediatric Patients with Scald Injury
This article reviews a single burn center experience with porcine xenografts to treat pediatric scald injuries, over a 10-year period. The authors compare xenografting to autografting, as well as wound care only, and provide outcome data on length of stay, incidence of health care–associated infections, and need for reconstructive surgery
Blood utilization in patients with burn injury and association with clinical outcomes (CME)
Uncontrolled bleeding is an important cause of increased transfusion in burn victims; however, description of blood utilization patterns in the burn population is lacking
Large meteoroids from the 2P/Encke complex : orbital data of 2010 taurids recorded in the framework of the Spanish fireball network
Cometary disruptions are though to be
an important source of Near Earth Objects (heareafter
NEOs). A continuous monitoring of meteor showers
from multistation networks on the ground allows to get
valuable orbital information of large meteoroids producing
fireballs. From such orbits can be established
conections with the orbital elements of diferent asteroids
or comets. In 2010 we started a program to get
precise orbital information of very bright Taurid bolides
in order to try to identify possible associations
with members of the NEO population [1]. We have
already identified some meteoroids that could be dynamically
associated with some NEOs currently identified
as members of the Taurid complex. This group of
bodies is formed by about 20 NEOs that presumably
formed by the fragmentation of a giant comet over the
past 20-30 kyr [2-4]. Some of these bodies have orbital
affinities to comet 2P/Encke, but recent studies have
found other asteroids in Apollo-like orbits that can be
good candidates to trace a progressive cometary disruption
that at different stages as a by-product produced
the Taurid meteoroid branches [3, 4]. It is important
to remark that the NEOs associated with the
Taurid meteoroid streams are presumably dark, as
seems to confirm the spectral information obtained for
the largests members (e.g. 16960 belongs to the B
spectral class [5]). Consequently these bodies are
among the most difficult and hazardous NEOs that
remain to be discovered. In fact, the Tunguska object
has been temptatively associated with the Taurid complex
[6]. A recent paper also links the Earth’s intersection
with the debris produced by the disruption of the
cometary progenitor with a possible Palaeolithic extinction
occurred around 12,900 BP [7]. Our orbital
studies of Taurid meteoroids could also identify other
members of the complex by using association criteria
and backwards integration of their orbits. In fact we
have found some Taurid complex members that are
exhibiting orbits not directly linked with the two main
branches. Obviously, having the Taurid complex some
members with about 100 meters in diameter [4], we
suspect of the existence of much more bodies in such a
range of sizes not discovered yet. These objects could
also produce meteorite-droping bolides in determinate
favourable geometric circumstances [1]
Glucocorticoid receptor mRNA levels are selectively decreased in neutrophils of children with sepsis
Objective: Corticosteroids are used in sepsis treatment to benefit outcome. However, discussion remains on which patients will benefit from treatment. Inter-individual variations in cortisol sensitivity, mediated through the glucocorticoid receptor, might play a role in the observed differences. Our aim was to study changes in mRNA levels of three glucocorticoid receptor splice variants in neutrophils of children with sepsis. Patients and design: Twenty-three children admitted to the pediatric intensive care unit with sepsis or septic shock were included. Neutrophils were isolated at days 0, 3 and 7, and after recovery (>3 months). mRNA levels of the glucocorticoid receptor splice variants GR-α (determining most of the cortisol effect), GR-P (increasing GR-α effect) and GR-β (inhibitor of GR-α) were measured quantitatively. Main results: Neutrophils from sepsis patients showed decreased levels of glucocorticoid receptor mRNA of the GR-α and GR-P splice variants on day 0 compared to after recovery. GR-α and GR-P mRNA levels showed a gradual recovery on days 3 and 7 and normalized after recovery. GR-β mRNA levels did not change significantly during sepsis. GR expression was negatively correlated to interleukin-6 (a measure of disease severity, r = -0.60, P = 0.009). Conclusions: Children with sepsis or septic shock showed a transient depression of glucocorticoid receptor mRNA in their neutrophils. This feature may represent a tissue-specific adaptation during sepsis leading to increased cortisol resistance of neutrophils. Our study adds to understanding the mechanism of cortisol sensitivity in immune cells. Future treatment strategies, aiming at timing and tissue specific regulation of glucocorticoids, might benefit patients with sepsis or septic shock
Protection of Spanish Ibex (Capra pyrenaica) against Bluetongue Virus Serotypes 1 and 8 in a Subclinical Experimental Infection
Many wild ruminants such as Spanish ibex (Capra pyrenaica) are susceptible to Bluetongue virus (BTV) infection, which causes disease mainly in domestic sheep and cattle. Outbreaks involving either BTV serotypes 1 (BTV-1) and 8 (BTV-8) are currently challenging Europe. Inclusion of wildlife vaccination among BTV control measures should be considered in certain species. In the present study, four out of fifteen seronegative Spanish ibexes were immunized with a single dose of inactivated vaccine against BTV-1, four against BTV-8 and seven ibexes were non vaccinated controls. Seven ibexes (four vaccinated and three controls) were inoculated with each BTV serotype. Antibody and IFN-gamma responses were evaluated until 28 days after inoculation (dpi). The vaccinated ibexes showed significant (P<0.05) neutralizing antibody levels after vaccination compared to non vaccinated ibexes. The non vaccinated ibexes remained seronegative until challenge and showed neutralizing antibodies from 7 dpi. BTV RNA was detected in the blood of non vaccinated ibexes from 2 to the end of the study (28 dpi) and in target tissue samples obtained at necropsy (8 and 28 dpi). BTV-1 was successfully isolated on cell culture from blood and target tissues of non vaccinated ibexes. Clinical signs were unapparent and no gross lesions were found at necropsy. Our results show for the first time that Spanish ibex is susceptible and asymptomatic to BTV infection and also that a single dose of vaccine prevents viraemia against BTV-1 and BTV-8 replication
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