3,149 research outputs found
Metallicity dependence of HMXB populations
High-mass X-ray binaries (HMXBs) might have contributed a non-negligible
fraction of the energy feedback to the interstellar and intergalactic media at
high redshift, becoming important sources for the heating and ionization
history of the Universe. However, the importance of this contribution depends
on the hypothesized increase in the number of HMXBs formed in low-metallicity
galaxies and in their luminosities. In this work we test the aforementioned
hypothesis, and quantify the metallicity dependence of HMXB population
properties. We compile from the literature a large set of data on the sizes and
X-ray luminosities of HMXB populations in nearby galaxies with known
metallicities and star formation rates. We use Bayesian inference to fit simple
Monte Carlo models that describe the metallicity dependence of the size and
luminosity of the HMXB populations. We find that HMXBs are typically ten times
more numerous per unit star formation rate in low-metallicity galaxies (12 +
log(O/H) < 8, namely < 20% solar) than in solar-metallicity galaxies. The
metallicity dependence of the luminosity of HMXBs is small compared to that of
the population size. Our results support the hypothesis that HMXBs are more
numerous in low-metallicity galaxies, implying the need to investigate the
feedback in the form of X-rays and energetic mass outflows of these high-energy
sources during cosmic dawn.Comment: 9 pages, 5 figures, accepted for publication in Astronomy &
Astrophysic
The 1755 earthquake in the Algarve (South of Portugal): what would happen nowadays?
The 1755 Lisbon earthquake, which reached a magnitude of 8.5, remains the most powerful and destructive to hit Europe so far. Within minutes, many lives were lost, populations displaced, livelihoods, homes and infrastructures were destroyed. Although frequently associated to the city of Lisbon, one of the most important European cities at the time, this earthquake caused similar damage and casualties, if not greater, in the southwest of the Algarve, where the seismic intensity was estimated at IX-X Mercalli Intensity Scale. Some time later a tsunami increased the number of victims and the amount of damage. In some locations the tsunami caused greater destruction than the earthquake itself. The tsunami hit both coasts of the North Atlantic; however, the more destructive damage occurred in the Portuguese coast, south from Lisbon, in the Gulf of Cadiz and in the Moroccan coast. The downtown of Lisbon was flooded by waves that reached a height of 6 m. The water flooded an area with an extension of around 250 m from the coast. In the Southwest part of Algarve the waves reached a height between 10 and 15 m and the flooded area was much larger. Through the analysis of recent research works on the assessment of the 1755 tsunami parameters and the interpretation of the more reliable historical documents, it is our intention to analyse the destructive power of the tsunami in the Algarve and delimit the flooded area. Using simple techniques of simulation it is our intention to assess the impacts nowadays of the occurrence of a tsunami similar to the one that hit the Algarve in 1755, which would probably affect a greater number of people, buildings and infrastructures. This assessment is an important instrument not only in terms of disaster preparedness but also for the integration of risk mitigation measures in land use planning
Self-assembled hyaluronic acid nanoparticles: effect of molecular weight and two different chemical approaches
INTRODUCTION: Natural polyssacharides, such as hyaluronic acid (HyA) have been widely used for biomedical and pharmaceutical applications. Hya has multiple functional groups available for chemical conjugation that can convert HyA into nano-sized carriers. We prepared self-assembled HyA nanoparticles by two different chemical derivatization techniques and used two different molecular weights HyA. Our aim was to compare these two techniques and evaluate the influence of molecular weight in the properties of HyA nanoparticles. (...)(undefined
Lamotrigine treatment of aggression in female borderline patients, Part II: an 18-month follow-up
Borderline patients often display pathological aggression. We previously tested lamotrigine, an anti-convulsant, in therapy for aggression in women with borderline personality disorder (BPD) (J Psychopharmacol 2005; 19: 287–291), and found significant changes on most scales of the State-Trait Anger Expression Inventory (STAXI) after eight weeks. To assess the longerterm efficacy of lamotrigine in therapy for aggression in women with BPD, this 18-month follow-up observation was carried out, in which patients (treated with lamotrigine: n = 18; former placebo group: n = 9) were tested every six months. According to the intent-to-treat principle, significant changes on all scales of the STAXI were observed in the lamotrigine-treated subjects. All subjects tolerated lamotrigine relatively well. Lamotrigine appears to be an effective and relatively safe agent in the longer-term treatment of aggression in women with BPD
Deaths by Choking with Food in Children: Legal Medical Aspects by Suffocation
The asphyxia by suffocation (choking) with foreign bodies are dramatic. Among
these, the choking with food are responsible for most of these deaths. Children under four
years old are particularly vulnerable due to not having a well-developed posterior dentition.
The paper presents the report of two cases of suffocation with food and discusses some legal
medical concepts, warning of the further prevention of such cases
A fatal case by a suicide kit containing sodium nitrite ordered on the internet
Fatal sodium nitrite poisonings are rare in the forensic context. The present work describes a first fatal case of sodium nitrite contained in a suicide kit that the victim acquired over the internet. The results of the autopsy showed general signs of asphyxia, such as intense cyanosis of the extremities, brown-gray-blue-red livor mortis, and some Tardieu petechiae in addition to intense visceral congestion. It is clear that forensic experts must be aware of the proliferation of this market and the risks of improper selling of these substances through suicide support networks available on the internet. The lack of knowledge of this reality may become unidentifiable, when toxicological analysis contemplates only the most classical and frequent substances involved in poisoning and reinforce the importance of a careful analysis of the death scene.info:eu-repo/semantics/publishedVersio
Leaching behavior of several zinc rich residues in a hydrometallurgical recycling process
The leaching of metals contained in spent Zn-MnO2 batteries and electric arc furnace (EAF) dusts using sulfuric acid solutions was studied, in order to evaluate the feasibility of simultaneous treatment of both wastes by a hydrometallurgical process. In both residues, a substantial quantity of zinc was solubilized (about 100% in batteries and 70-80% in EAF dusts) in diluted acid solutions and room temperature, corresponding to the reaction of zinc oxide species. Other species were more refractory to the chemical attack, namely the manganese (III or IV) oxides in batteries and the zinc ferrite in dusts, requiring higher temperatures (e.g. 90ºC) and higher leachant concentrations. Lead present in EAF dusts was not solubilized in sulfate media, thus remaining in the leach residue. Results seem to confirm the possibility of treatment of both zinc-containing residues by the same hydrometallurgical process, eventually involving two leaching stages – diluted acid leaching and hot acid leaching – followed by solution purification through iron precipitation and Zn/Mn separation and recovery. Concerning lead, a second leaching circuit in chloride media could be developed for its potential recovery
Peripapillary Retinal Nerve Fiber Layer Thickness and Peripheral Microcirculation in Raynaud’s Disease
Purpose: Normal-tension glaucoma has been associated with systemic vascular diseases such as peripheral vasospasm. This study aims to evaluate the influence of peripheral vasospasm on the thickness of the retinal nerve fiber layer (RNFL) in Raynaud's disease (RD), and the correlation between global RNFL and peripheral microcirculation features in RD patients. Methods: Observational cross-sectional study of 18 patients (35 eyes) with a diagnosis of RD followed in our clinic, and 20 healthy controls (39 eyes). RNFL parameters were obtained using spectral domain optical coherence tomography (SD-OCT Spectralis®, Heidelberg). Global and sectorial peripapillary RNFL thickness were registered. Age, gender, refractive error, best-corrected visual acuity and intraocular pressure were determined, and slit-lamp biomicroscopy and fundus examination were performed. Nailfold videocapillaroscopy (NC) was performed in the RD group to characterize capillary morphology and blood flow. Mann-Whitney and Fisher's exact tests were used for statistical analysis. Statistical significance level was set at p<0.05 (two-sided). Results: There was no significant difference in the global RNFL between RD patients and the control group (p=0.35). The presence of avascular areas in NC was associated with a lower global RNFL thickness (p=0.026). Conclusion: The association between avascular areas in NC and the lower global RNFL thickness in RD patients suggests that systemic vasospasm severity may be related to optic nerve damage propensity. Therefore, its presence in NC may identify RD patients at risk for optic nerve head damage. A larger sample with a long-term study is needed to support the clinical and therapeutic implications of our findings.info:eu-repo/semantics/publishedVersio
The importance of pelvic ring stabilization as a life-saving measure in pre-hospital - A case report commented by autopsy
Hip fractures with unstable pelvic ring have great morbidity and mortality rates. These fractures result from high energy trauma such as falls from heights, road accidents and collapsing structures or other similar mechanisms of action. We report the case of a 63 years old man, construction worker, who stood inside a ditch during a wall construction when he was surprised by this collapse, which resulted in direct trauma to the right thigh and pelvis. The autopsy revealed diaphysis fracture of the right femur with an open book pelvic fracture with severe hemorrhagic infiltration and hematoma of the pelvic muscles without arterial injury. Bone bleeding and the vascular damage associated with disruption of the sacroiliac ligaments promote a very significant bleeding. Simple maneuvers such as sheet circumferential compression to promote pelvic ring closure are effective on stabilizing and closure of the sacroiliac joint. Hip manipulation of the fracture was performed during the necropsy to demonstrate and prove how a simple sheet contention can promote stabilization of the pelvic ring by closing the sacroiliac joints in open book fractures.info:eu-repo/semantics/publishedVersio
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