Neutron-Star-Black-Hole Binaries Produced by Binary-Driven Hypernovae.

Binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (E_{iso}≳10^{52} erg), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed "ultrastripped" binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs.

Adaptation of olfactory threshold at high altitude.

The aim of this study was to investigate the effects of the extreme environment of high altitude hypoxia on olfactory threshold. The study was conducted before, during, and after a scientific expedition to Mera Peak (5,800 m). The n-butanol test was used for the assessment of the magnitude of the olfactory threshold. The finding was that the olfactory threshold dramatically increased at high altitude. We conclude that there is a physiological adaptation of olfaction due to altitude-hypoxia.

Cytoglobin and neuroglobin in the human brainstem and carotid body.

The aim of the present study was to evaluate the presence of Neuroglobin (Ngb) and Cytoglobin (Cygb) in the solitary tract nucleus (STN) and in the carotid body of human subjects. Transverse serial sections of formalin-fixed, paraffin-embedded brainstems, taken from six subjects, were investigated. Ngb and Cygb are expressed in both the structures. Differences in expression of Ngb and Cygb among dorsal and ventral area of the STN may be related to their different functions and different metabolic demands. Because the STN plays an important role in the processing of cardiovascular and respiratory reflex inputs, Ngb and Cygb may play an integrative central modulatory action for the two systems.

Pair plasma relaxation time scales.

By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic interactions. The collisional integrals are obtained directly from the corresponding QED matrix elements. Thermalization time scales are computed for a wide range of values of both the total-energy density (over 10 orders of magnitude) and of the baryonic loading parameter (over 6 orders of magnitude). This also allows us to study such interesting limiting cases as the almost purely electron-positron plasma or electron-proton plasma as well as intermediate cases. These results appear to be important both for laboratory experiments aimed at generating optically thick pair plasmas as well as for astrophysical models in which electron-positron pair plasmas play a relevant role.

Risk factors for a first thrombotic event in antiphospholipid antibody carriers. A multicentre, retrospective follow-up study.

OBJECTIVES: To asses risk factors for a first thrombotic event in antiphospholipid antibody (aPL) positive carriers and evaluate the efficacy of prophylactic treatments. METHODS: Recruitment criteria were age 18-65 years, no history of thrombosis, positivity for lupus anticoagulant and/or IgG/IgM anticardiolipin antibody (aCL) on > or =2 occasions at least 6 weeks apart. Demographic, laboratory and clinical parameters were collected at enrolment and at the time of the thrombotic event. RESULTS: 370 patients/subjects (mean (SD) age 34 (9.9) years) were analysed retrospectively for a mean (SD) follow-up of 59.3 (45.5) months. Thirty patients (8.1%) developed a first thrombotic event during follow-up. Hypertension and medium/high levels of IgG aCL were identified by multivariate logistic regression analysis as independent risk factors for thrombosis. Thromboprophylaxis during high-risk and long-term periods was significantly protective. CONCLUSIONS: Hypertension or medium/high titres of IgG aCL are risk factors for a first thrombotic event in asymptomatic aPL carriers and primary prophylaxis is protective.

Thermalization of nonequilibrium electron-positron-photon plasmas.

Starting from a nonequilibrium configuration we analyze the role of the direct and the inverse binary and triple interactions in reaching thermal equilibrium in a homogeneous isotropic pair plasma. We focus on energies in the range 0.1-10 MeV. We numerically integrate the relativistic Boltzmann equation with the exact QED collisional integrals taking into account all binary and triple interactions. We show that first, when a detailed balance is reached for all binary interactions on a time scale t(k) < or approximately 10(-14) sec, photons and electron-positron pairs establish kinetic equilibrium. Subsequently, when triple interactions satisfy the detailed balance on a time scale t(eq) < or approximately 10(-12) sec, the plasma reaches thermal equilibrium. It is shown that neglecting the inverse triple interactions prevents reaching thermal equilibrium. Our results obtained in the theoretical physics domain also find application in astrophysics and cosmology.

Elevated plasma homocysteine in acute stroke was not associated with severity and outcome: stronger association with small artery disease.

Homocysteine increases in the acute phase of ischaemic stroke and from the acute to the convalescent phase, suggesting that hyper-homocysteinaemia may be a consequence rather than a causal factor. Therefore we measured homocysteine plasma levels in stroke patients in order to investigate possible correlations of homocysteine with stroke severity and clinical outcome. Further we looked for eventual differences in stroke subtypes. We prospectively studied plasma homocysteine levels in acute stroke patients admitted to the stroke unit of our department. Seven hundred and seventy-five ischaemic stroke patients, 39 cerebral haemorrhages and 421 healthy control subjects have been enrolled. Stroke severity and clinical outcome were measured with the Scandinavian Stroke Scale, the Rankin Scale and the Barthel Index. Stroke severity by linear stepwise regression analysis was not an independent determinant of plasma homocysteine levels. Homocysteine was not correlated with outcome measured by the Barthel Index. Mean plasma homocysteine of both ischaemic and haemorrhagic stroke was significantly higher than controls (p<0.05). Homocysteine had an adjusted odds ratios (OR) of 4.2 (95% CI 2.77-6.54) for ischaemic stroke and of 3.69 (95% CI 1.90-7.17) for haemorrhagic stroke. Compared with the lowest quartile, the upper quartile was associated with an adjusted OR of ischaemic stroke due to small artery disease of 17.4 (95% CI 6.8-44.3). Homocysteine in the acute phase of stroke was not associated with stroke severity or outcome. Elevated plasma homocysteine in the acute phase of stroke was associated with both ischaemic and haemorrhagic stroke. Higher levels are associated with higher risk of small artery disease subtype of stroke.

Undetected breech presentation: impact on external version and cesarean rates.

The objective of this study was to determine the impact of undetected breech presentation on an external cephalic version program. We performed a retrospective analysis of all external cephalic versions attempted over a 1-year interval. We then analyzed all cesarean operations performed for the indication of breech presentation over the same interval. Cases involving twin gestations and premature births were excluded. We found that 21% of term breech presentations were not detected before the onset of labor and an additional 15% were not detected until after 38 weeks' gestation. Increased third-trimester screening for breech presentation could potentially decrease the need for cesarean delivery.

[Askin's tumor in a young adult: a rare occurrence. Apropos one case observed]. / Il tumore di Askin in un giovane adulto: una rara evenienza. A proposito di un caso osservato.

Askin's tumour is a rare malignant small cell neoplasia of the thoracic wall; it most often effects females during childhood and is characterised by limited survival. The authors report a recent case of Askin's tumour in a young adult male. The case was characterised by multiple recidivation but a long survival. The authors discuss its diagnosis and treatment.

Monitoring heparin anticoagulation and its neutralization.

Heparin anticoagulation and its neutralization were monitored by three different techniques: a manual protamine titration, an automated activated coagulation time, and an automated protamine titration. All three techniques provided satisfactory information. The decision of which to use must be based on other considerations such as available manpower and cost of equipment. The effect of using the automated protamine titration test on heparin and protamine requirements, and on blood loss measured intraoperatively after bypass and in overnight chest bottle drainage in two groups of comparable patients undergoing coronary artery bypass operation was studied. The heparin requirements were similar (24,420 +/- 584 units, control group; 23,550 +/- 849 units, treatment group), but the protamine requirements were markedly different (429 +/- 14.7 mg, control; 258 +/- 10.4 mg, treatment; p < 0.05). There was no statistical difference in intraoperative blood loss or overnight chest bottle drainage.