131,865 research outputs found
The One-Armed Spiral Instability in Neutron Star Mergers and its Detectability in Gravitational Waves
No full text<p>We distribute complete gravitational-wave signals in the Advanced LIGO band (10 Hz - 8192 Hz) of the inspiral and merger of two neutron stars. These waveforms been constructed by hybridizing numerical-relativity data obtained with the WhiskyTHC code [1] with tidal effective-one-body waveforms [2,3]. More details on the procedure used to generate these waveforms are given in [4]. </p>
<p>The waveforms are distributed as HDF5 files containing the amplitude and phase of the -2 spin-weighted spherical harmonics multipoles of the strain:</p>
<p><span class="math-tex"></span></p>
<p>where <span class="math-tex"></span> is the distance in cm from the source.</p>
<p>The data files include a machine readable "/metadata" group with:</p>
<ul>
<li>/metadata/EOS: name of the equation of state</li>
<li>/metadata/M_{A|B}: mass in isolation of star A (or B) in grams</li>
<li>/metadata/R_{A|B}: radius of star A (or B) in cm</li>
<li>/metadata/k2T: tidal coupling constant of the binary (see [3])</li>
<li>/metadata/kl_{A|B}: l=2,3,4 dimensionless Love numbers of star A (or B)</li>
</ul>
<p>We store amplitude and phase for multipoles modes up to l=4 as time series sampled at 16384 Hz.</p>
<p>We make these waveforms freely available in the hope that they will be useful. We kindly ask you to cite [3] and [4] in any publication resulting from the use of these waveforms.</p>
<p>---<br />
[1] http://www.tapir.caltech.edu/~david_e/whiskythc.html<br />
[2] https://eob.ihes.fr/<br />
[3] S. Bernuzzi, A. Nagar, T. Dietrich, T. Damour; Modeling the Dynamics of Tidally Interacting Binary Neutron Stars up to the Merger; Phys.Rev.Lett. 114 (2015) 16, 161103.<br />
[4] D. Radice, S. Bernuzzi, C. D. Ott; The One-Armed Spiral Instability in Neutron Star Mergers and its Detectability in Gravitational Waves; arXiv:1603.05726.</p>
A semiparametric bivariate probit model for joint modeling of outcomes in STEMI patients
No full textIn this work we analyse the relationship among in-hospital mortality and a treatment effectiveness outcome in patients affected by ST-Elevation myocardial infarction. The main idea is to carry out a joint modeling of the two outcomes applying a Semiparametric Bivariate Probit Model to data arising from a clinical registry called STEMI Archive. A realistic quantification of the relationship between outcomes can be problematic for several reasons. First, latent factors associated with hospitals organization can affect the treatment efficacy and/or interact with patient’s condition at admission time. Moreover, they can also directly influence the mortality outcome. Such factors can be hardly measurable. Thus, the use of classical estimation methods will clearly result in inconsistent or biased parameter estimates. Secondly, covariate-outcomes relationships can exhibit nonlinear patterns. Provided that proper statistical methods for model fitting in such framework are available, it is possible to employ a simultaneous estimation approach to account for unobservable confounders. Such a framework can also provide flexible covariate structures and model the whole conditional distribution of the response
Optimal low-thrust trajectories to asteroids through an algorithm based on differential dynamic programming
No full textIn this paper an optimisation algorithm based on Differential Dynamic Programming is applied to the design of rendezvous and fly-by trajectories to near Earth objects. Differential dynamic programming is a successive approximation technique that computes a feedback control law in correspondence of a fixed number of decision times. In this way the high dimensional problem characteristic of low-thrust optimisation is reduced into a series of small dimensional problems. The proposed method exploits the stage-wise approach to incorporate an adaptive refinement of the discretisation mesh within the optimisation process. A particular interpolation technique was used to preserve the feedback nature of the control law, thus improving robustness against some approximation errors introduced during the adaptation process. The algorithm implements global variations of the control law, which ensure a further increase in robustness. The results presented show how the proposed approach is capable of fully exploiting the multi-body dynamics of the problem; in fact, in one of the study cases, a fly-by of the Earth is scheduled, which was not included in the first guess solution
Interception and deviation of near earth objects via solar collector strategy
No full textA solution to the asteroid deviation problem via a low-thrust strategy is proposed. This formulation makes use of the proximal motion equations and a semi-analytical solution of the Gauss planetary equations. The average of the variation of the orbital elements is computed, together with an approximate expression of their periodic evolution. The interception and the deflection phase are optimised together through a global search. The low-thrust transfer is preliminary designed with a shape based method; subsequently the solutions are locally refined through the Differential Dynamic Programming approach. A set of optimal solutions are presented for a deflection mission to Apophis, together with a representative trajectory to Apophis including the Earth escape
Treatment of Chylothorax after Lung Resection: Indications, Timing, and Outcomes
No full textBackground Chylothorax following pulmonary resection and lymphadenectomy for cancer is a potential severe complication in thoracic surgery. In the present study, we investigated the efficacy of the nonsurgical approach as well as the need for reoperation after conservative approach failure. Methods Chylothorax was diagnosed when chylous leakage from the chest drainage was observed and confirmed by the presence of triglycerides in the pleural fluid. We initially treated all the patients conservatively with complete oral intake cessation and total parenteral nutrition; if drainage output remained more than 800 mL/d after the first 5 days or major pleural effusion was observed at chest X-ray after chest tube removal, surgical treatment of chylothorax was indicated. Results Between January 1998 and December 2018, 5,072 patients underwent standard anatomical resection and mediastinal lymph node dissection for cancer at our institution. Among them, 30 patients (0.6%) developed chylothorax: 20 patients were effectively treated only by nil per os and low-fat diet, while 10 patients (33.3%) required surgical treatment. Mean age was 63 years; there were 24 male patients (80%); right-sided chylothorax was more frequent than left-sided chylothorax (22 vs. 8, respectively) although not statistically significant (p = 0.38); the only factor that seems to influence the need for reoperation is chylothorax flow rate during conservative treatment (p = 0.06). Conclusion Conservative treatment is effective in the case of low flow-rate chylothorax (< 800 mL/d); in the case of a higher flow rate, surgical exploration is needed and thoracic duct ligation-with or without lymphatic sites clipping-provides definitive lymphostasis
Enuresi prolungata e sviluppo della sessualità maschile:il punto di vista psicodinamico
No full text
Carbendazim and n-butylisocyanate: metabolites responsible for benomyl double action on cytochrome P450 in HepG2 cells
No full textChanges in the cytochrome P350 monooxygenase system wereinvestigated in HepG2 cells treated for 24 h with 1.25, 2.5, 5, 10 and 20 μg/ml of carbendazim (MBC) and n-butylisocyanate (BIC), the principal benomyl metabolites. The results show that n-butylisocyanate leads to a decrease in both ethoxyresorufin deethylase (P4501A1) (EROD) and ethoxycoumarin deethylase (P4502B) (ECOD), whereas MBC has no effect on EROD and increases ECOD. The decrease in ECOD and EROD activities after BIC treatment can be attributed to the detrimental action of this substance. The MBC-induced increase in ethoxycoumarin can be considered an enzyme-specific inductive phenomenon. This hypothesis was confirmed by Western immunoblot analysis and treatment with actinomycin D 8 x 10-4 μM: the first showed an increase in P4502B isoenzyme content and the second evidence of a partial block of the increase in ECOD activity induced by MBC. Given these results, MBC and BIC seem to be the metabolites responsible for the double opposite action of their parent compound benomyl. Data deriving from an equimolar mixture of the two metabolites suggest that benomyl activity on some cytochrome P450 isoenzymes is the result of a balance between the action of the single metabolites (Radice et al., 1996)
A New Tool to Estimate Inundation Depths by Spatial Interpolation (RAPIDE): Design, Application and Impact on Quantitative Assessment of Flood Damages
No full textRapid tools for the prediction of the spatial distribution of flood depths within inundated areas are necessary when the implementation of complex hydrodynamic models is not possible due to time constraints or lack of data. For example, similar tools may be extremely useful to obtain first estimates of flood losses in the aftermath of an event, or for large-scale river basin planning. This paper presents RAPIDE, a new GIS-based tool for the estimation of the water depth distribution that relies only on the perimeter of the inundation and a digital terrain model. RAPIDE is based on a spatial interpolation of water levels, starting from the hypothesis that the perimeter of the flooded area is the locus of points having null water depth. The interpolation is improved by (i) the use of auxiliary lines, perpendicular to the river reach, along which additional control points are placed and (ii) the possibility to introduce a mask for filtering interpolation points near critical areas. The reliability of RAPIDE is tested for the 2002 flood in Lodi (northern Italy), by comparing the inundation depth maps obtained by the rapid tool to those from 2D hydraulic modelling. The change of the results, related to the use of either method, affects the quantitative estimation of direct damages very limitedly. The results, therefore, show that RAPIDE can provide accurate flood depth predictions, with errors that are fully compatible with its use for river-basin scale flood risk assessments and civil protection purpose
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