Magnetic fields generated by r-modes in accreting millisecond pulsars

In millisecond pulsars the existence of the Coriolis force allows the development of the so-called Rossby oscillations (r-modes) which are know to be unstable to emission of gravitational waves. These instabilities are mainly damped by the viscosity of the star or by the existence of a strong magnetic field. A fraction of the observed millisecond pulsars are known to be inside Low Mass X-ray Binaries (LMXBs), systems in which a neutron star (or a black hole) is accreting from a donor whose mass is smaller than 1 $M_\odot$. Here we show that the r-mode instabilities can generate strong toroidal magnetic fields by inducing differential rotation. In this way we also provide an alternative scenario for the origin of the magnetars.Comment: 6 pages, 3 figures, Proceedings conference "Theoretical Nuclear Physics", Cortona October 200

A Model of ICDT Internet flows on mobile devices for the travel and tourism consumer

Despite the increasing use of mobile devices and their applications in the travel and tourism arena, there is a lack of literature that considers how mobile device tourism applications could be evaluated. Built around a discussion of information attributes (a series of dimensions by which the delivery of information can be assessed) that have been specifically developed for the tourism sector and an examination of the specific characteristics of mobile devices, this theoretical article classifies different online tourism applications that can be accessed by mobile devices according to Angehrn's four virtual spaces (information, communication, distribution, and transaction). This is for the purpose of demonstrating that the majority of applications in the mobile tourism arena eventually fall within the realm of information provision and can thus be assessed according to how they perform in relation to information attributes. A model of ICDT Internet flows on mobile devices for the travel and tourism consumer is presented

Generation of strong magnetic fields by r-modes in millisecond accreting neutron stars: induced deformations and gravitational wave emission

Differential rotation induced by the r-mode instability can generate very strong toroidal fields in the core of accreting, millisecond spinning neutron stars. We introduce explicitly the magnetic damping term in the evolution equations of the r-modes and solve them numerically in the Newtonian limit, to follow the development and growth of the internal magnetic field. We show that the strength of the latter can reach large values, $B \sim 10^{14}$ G, in the core of the fastest accreting neutron stars. This is strong enough to induce a significant quadrupole moment of the neutron star mass distribution, corresponding to an ellipticity |\epsilon_B}| \sim 10^{-8}. If the symmetry axis of the induced magnetic field is not aligned with the spin axis, the neutron star radiates gravitational waves. We suggest that this mechanism may explain the upper limit of the spin frequencies observed in accreting neutron stars in Low Mass X-Ray Binaries. We discuss the relevance of our results for the search of gravitational waves.Comment: 11 pages, 8 figure

Echocardiography combined with cardiopulmonary exercise testing for the prediction of outcome in idiopathic pulmonary arterial hypertension

BACKGROUND: Right ventricular (RV) function is a major determinant of exercise intolerance and outcome in idiopathic pulmonary arterial hypertension (IPAH). The aim of the study was to evaluate the incremental prognostic value of echocardiography of the RV and cardiopulmonary exercise testing (CPET) on long-term prognosis in these patients. METHODS: One hundred-thirty treatment-naïve IPAH patients were enrolled and prospectively followed. Clinical worsening (CW) was defined by a reduction in 6-minute walk distance plus an increase in functional class, or non elective hospitalization for PAH, or death. Baseline evaluation included clinical, hemodynamic, echocardiographic and CPET variables. Cox regression modeling with c-statistic and bootstrapping validation methods were done. RESULTS: During a mean period of 528 ± 304 days, 54 patients experienced CW (53%). Among demographic, clinical and hemodynamic variables at catheterization, functional class and cardiac index were independent predictors of CW (Model-1). With addition of echocardiographic and CPET variables (Model-2), peak O2 pulse (peak VO2/heart rate) and RV fractional area change (RVFAC) independently improved the power of the prognostic model (AUC: 0.81 vs 0.66, respectively; p=0.005). Patients with low RVFAC and low O2 pulse (low RVFAC + low O2 pulse) and high RVFAC+low O2 pulse showed 99.8 and 29.4 increase in the hazard ratio, respectively (relative risk -RR- of 41.1 and 25.3, respectively), compared with high RVFAC+high O2 pulse (p=0.0001). CONCLUSIONS: Echocardiography combined with CPET provides relevant clinical and prognostic information. A combination of low RVFAC and low O2 pulse identifies patients at a particularly high risk of clinical deterioration

Electronic Transport in the Oxygen Deficient Ferromagnetic Semiconducting TiO2−δ_{2-\delta}

TiO$_{2-\delta}$ films were deposited on (100) Lanthanum aluminates LaAlO$_{3}$ substrates at a very low oxygen chamber pressure $P\approx 0.3$ mtorr employing a pulsed laser ablation deposition technique. In previous work, it was established that the oxygen deficiency in these films induced ferromagnetism. In this work it is demonstrated that this same oxygen deficiency also gives rise to semiconductor titanium ion impurity donor energy levels. Transport resistivity measurements in thin films of TiO$_{2-\delta}$ are presented as a function of temperature and magnetic field. Magneto- and Hall- resistivity is explained in terms of electronic excitations from the titanium ion donor levels into the conduction band.Comment: RevTeX4, Four pages, Four Figures in ^.eps forma

The 2007 ERA-EDTA Registry Annual Report—a Précis

Introduction: This paper provides a summary of the 2006 European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry report. Methods: Data on renal replacement therapy (RRT) were available from 50 national and regional registries in 28 countries in Europe and bordering the Mediterranean Sea. Data sets with individual patient data were received from 35 registries, whereas 17 registries contributed data in aggregated form. For both types of registries we presented incidence, prevalence and transplant rates. Survival analysis and the calculation of expected remaining lifetimes were solely based on individual patient records.Results: In 2006, among all registries reporting to the ERA-EDTA Registry, the overall annual incidence rate of RRT was 118 per million population (pmp), and the prevalence was 630 pmp. Incidence rates varied from 213 pmp in Germany to 18 pmp in Ukraine. The overall incidence rate of RRT for end-stage renal disease (ESRD) started to decrease from 2004. The highest prevalence of RRT for ESRD was reported by Cantabria, Spain (1,234 pmp) and the lowest by Ukraine (73 pmp). Overall transplant rates were highest in Spain (61 pmp), whereas the highest transplant rates with living donor kidneys were reported from Iceland (26 pmp). The unadjusted 1-, 2- and 5-year survival of patients on RRT was 82.3 (95% confidence interval [95% CI], 82.0-82.5), 70.9 (95% CI, 70.7-71.2) and 47.5 (95% CI, 47.3-47.6) for the cohort 1997-2001, respectivel

Prognostic value of combined use of biomarkers of inflammation, endothelial dysfunction, and myocardiopathy in patients with ESRD

Prognostic value of combined use of biomarkers of inflammation, endothelial dysfunction, and myocardiopathy in patients with ESRD.BackgroundCardiovascular risk stratification is important in the clinical management of patients with end-stage renal diseases (ESRD) and biomarkers are increasingly used in these patients.MethodsIn a cohort of 246 dialysis patients without heart failure at baseline we tested the combined prognostic power of three well-established biomarkers: brain natriuretic peptide (BNP), C-reactive protein (CRP), and asymmetric dimethyl arginine (ADMA). The independent prognostic value of individual and combined biomarkers was estimated in separate Cox models, including standard risk factors in dialysis patients and comorbidities.ResultsWhen the prediction power of the three biomarkers was evaluated individually, BNP, ADMA, and CRP added significant predictive value (P≤ 0.01) to all-cause and cardiovascular mortality models and the explanatory gain attributable to these biomarkers were of similar degree (ranging from 3.3% to 5.7%). When the biomarkers were evaluated jointly, a score based on the BNP-CRP combination, increased by 9.9% (all-cause) and by 10.5% (cardiovascular) the explained mortality variance of standard Cox models and such gain in power was similar to that achieved by the CRP-ADMA combination (all-cause death 9.0% and cardiovascular death 8.4%). Of note, the explanatory gain derived by the simultaneous use of the three biomarkers was very similar (all-cause death 11.6% and cardiovascular death 10.5%) to that achieved by the use of two biomarkers.ConclusionThese findings indicate a potential role for CRP, BNP, and ADMA to be incorporated into diagnostic and therapeutic strategies aimed at detection and treatment of atherosclerotic complications and at preventing heart failure in the dialysis population