205 research outputs found

    Is there room for highly magnetized pulsar wind nebulae among those non-detected at TeV?

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    We make a time-dependent characterization of pulsar wind nebulae (PWNe) surrounding some of the highest spin-down pulsars that have not yet been detected at TeV. Our aim is assessing their possible level of magnetization. We analyze the nebulae driven by J2022+3842 in G76.9+1.0, J0540-6919 in N158A (the Crab twin), J1400--6325 in G310.6--1.6, and J1124--5916 in G292.0+0.18, none of which have been found at TeV energies. For comparison we refer to published models of G54.1+0.3, the Crab nebula, and develop a model for N157B in the Large Magellanic Cloud (LMC). We conclude that further observations of N158A could lead to its detection at VHE. According to our model, a FIR energy density of 5 eV cm3^{-3} could already lead to a detection in H.E.S.S. (assuming no other IC target field) within 50 hours of exposure and just the CMB inverse Compton contribution would produce VHE photons at the CTA sensitivity. We also propose models for G76.9+1.0, G310.6--1.6 and G292.0+1.8 which suggest their TeV detection in a moderate exposure for the latter two with the current generation of Cherenkov telescopes. We analyze the possibility that these PWNe are highly magnetized, where the low number of particles explains the residual detection in X-rays and their lack of detection at TeV energies.Comment: Accepted for publication in MNRA

    The effects of magnetic field, age, and intrinsic luminosity on Crab-like pulsar wind nebulae

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    We investigate the time-dependent behavior of Crab-like pulsar wind nebulae (PWNe) generating a set of models using 4 different initial spin-down luminosities (L0={1,0.1,0.01,0.001}×L0,CrabL_0 =\{1,0.1,0.01,0.001\} \times L_{0, {\rm Crab}}), 8 values of magnetic fraction (η=\eta = 0.001, 0.01, 0.03, 0.1, 0.5, 0.9, 0.99, and 0.999, i.e., from fully particle dominated to fully magnetically dominated nebulae), and 3 distinctive ages: 940, 3000, and 9000 years. We find that the self-synchrotron Compton (SSC) contribution is irrelevant for LSDL_{SD}=0.1, 1, and 10% of the Crab power, disregarding the age and the magnetic fraction. SSC only becomes relevant for highly energetic (70\sim 70% of the Crab), particle dominated nebulae at low ages (of less than a few kyr), located in a FIR background with relatively low energy density. Since no pulsar other than Crab is known to have these features, these results clarify why the Crab Nebula, and only it, is SSC dominated. No young PWN would be detectable at TeV energies if the pulsar's spin-down power is 0.1% Crab or lower. For 1% of the Crab spin-down, only particle dominated nebulae can be detected by H.E.S.S.-like telescopes when young enough (with details depending on the precise injection and environmental parameters). Above 10% of the Crab's power, all PWNe are detectable by H.E.S.S.-like telescopes if they are particle dominated, no matter the age. The impact of the magnetic fraction on the final SED is varied and important, generating order of magnitude variations in the luminosity output for systems that are otherwise the same (equal PP, P˙\dot P, injection, and environment).Comment: Accepted for publication in MNRA

    Valutazione e gestione dei rischi per la salute dei lavoratori nello scavo meccanico di gallerie

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    La presente relazione costituisce il compendio di quanto discusso all’interno del seminario organizzato anche con valenza formativa nell’ambito del Master di 2° livello in Ingegneria per la Sicurezza Occupazionale -MISO- e accreditato Educazione Continua in Medicina -ECM-, dal titolo “Valutazione e gestione dei rischi per la salute dei lavoratori nello scavo meccanico di gallerie”. Nei vari interventi, dopo un inquadramento sulle moderne tecniche di scavo meccanico, sono trattati i criteri di approccio per la valutazione e gestione dei principali inquinanti di formazione o generati durante la lavorazione. Sono in particolare approfonditi gli aspetti connessi con la definizione di valori di concentrazione accettabili con uno scenario normativo tuttora in marcata evoluzione. L’ultima parte fornisce indicazioni sulla gestione della sicurezza in coerenza con il moderno approccio in Prevention through Design -PtD- e in qualità, in condizioni normali ed in caso di deviazioni ragionevolmente attendibili. Nel suo insieme quindi, quanto esposto può costituire riferimento aggiornato sullo stato dell’arte in materia di sicurezza per lo scavo meccanico delle gallerie

    The antenna DSA 3 and its potential use for Radio Astronomy

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    The European Space Agency (ESA) will inaugurate its third Deep Space Antenna (DSA 3) by the end of 2012. DSA 3 will be located in Argentina near the city of Malarg"ue in the Mendoza province. While the instrument will be primarily dedicated to communications with interplanetary missions, the characteristics of its antenna and receivers will also enable standalone leading scientific contributions, with a high scientific-technological return. We outline here scientific proposals for a radio astronomical use of DSA 3.Comment: 4 pages, submitted as Proceedings for the BAA

    Meeting patient expectations in migraine treatment: what are the key endpoints?

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    Clinical outcomes of migraine treatment are generally based on two major endpoints: acute pain resolution and effects on quality of life (QOL). Resolution of acute pain can be evaluated in a number of ways, each increasingly challenging to achieve; pain relief, pain freedom at 2 h, sustained pain-freedom, and SPF plus no adverse events (SNAE, the most challenging). QOL questionnaires help assess the burden of migraine and identify optimal treatments. Pain resolution and improved QOL form the basis of the ultimate target-meeting patient expectations, to achieve patient satisfaction. To achieve this, it is crucial to choose appropriate endpoints that reflect realistic treatment goals for individual patients. Moreover, SNAE can help discriminate between triptans, with almotriptan having the highest SNAE score. Kaplan-Meier plots are also relevant when evaluating migraine treatments. The use of symptomatic medication may lead to the paradoxical development of medication-overuse headache. In general practice, patients should use simple tools for pain measurement (e.g. headache diary) and a QOL questionnaire. A composite endpoint of pain resolution and QOL restoration would constitute a step forward in migraine management

    Endovascular treatment of thoracic aortic disease: Four years of experience

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    Background-The aim of this retrospective study is to investigate efficacy and middle-term results of the stent graft treatment for diseases of descending thoracic aorta. Methods and Results-From March 1999 to October 2003, 132 patients (113 male and 19 female, mean age 62±14 years) were enrolled. They were divided into 4 groups: aneurysms (43, group A), post-traumatic lesions (24, group B), and complicated type B dissections (43, group C). Twenty-two further patients, with chronic type B dissection and not suitable for endovascular or surgical or hybrid techniques because of multiple entry tears without difference between the true and false lumen and poor clinical conditions, were obliged to receive medical management only (group D). All patients underwent computed tomography (CT) scan and angiography as preoperative assessment. An optimal deployment with exclusion of the aneurysm and/or closure of the entry tear in dissection was achieved in 96.4% (106/110) of the patients that were discharged in good conditions within 6 days. No spinal cord injuries were observed. The follow-up (average 20.82±10.01 months, range 1 to 55 months), performed with serial chest CT scans, was 100% complete. No stent graft-related complications were detected, although only in 1 case, an asymptomatic rupture of the Excluder connecting bar was found with a perforation of the fabric and an intra-aortic exposition of the bar itself. In 2 patients with chronic dissection an asymptomatic type II endoleak was detected. A total of 4 hospital deaths resulted in an overall operative mortality of 3.9%. Seven patients (6.3%) died during the follow-up 5 of them for other diseases (4.5%). However, a 40.9% mortality was observed within the obliged medical treatment group. Conclusions-Endovascular treatment of thoracic aortic diseases, even in the acute phase, may represent a valid option with a low mortality rate. Moreover, the efficacy is proved in the middle-term whereas the long-term follow-up is still pending

    Decision Support System for target prostate biopsy outcome prediction: Clustering and FP-growth algorithm for fuzzy rules extraction

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    An automated and data-driven rules extraction is crucial for the construction of Fuzzy Inference Systems (FIS). This work presents a method for extracting fuzzy rules based on clustering and association mining through the FP-growth algorithm. First, Self Organizing Maps are used to identify subsets of elements with similar characteristics, separately for each class. Then, the FP-Growth algorithm is applied to each cluster. Elements matching each rule are subdivided in the corresponding classes and only rules showing a predominance of elements belonging to one class are used as fuzzy rules. The method was applied to the construction of a Decision Support System based on FIS for the target prostate biopsy outcome prediction based on six pre-bioptic variables. A dataset containing 1447 patients (824 with positive outcome, 623 with negative outcome) was used. Four and six clusters were identified for the positive and the negative class, respectively. A total of 151 rules were extracted with FP-Growth algorithm and 29 were included in the FIS. The system was able to classify 927 patients out of 1447. On the classi-fied subjects, it reached a sensitivity of 87.5% and a specificity of 58.8%

    Adaptation of the Penetration-Aspiration Scale to Open Partial Horizontal Laryngectomy: reliability analysis

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    The study aimed at adapting the Penetration-Aspiration scale to OPHL and analysing its reliability

    The Penetration–Aspiration Scale: Adaptation to Open Partial Laryngectomy and Reliability Analysis

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    A standard for assessing swallowing function after open partial horizontal laryngectomy (OPHL) is still not established. The variability in the measures used to investigate swallowing functional outcomes after OPHL limits the communication among clinicians and the possibility to compare and combine results from different studies. The study aims to adapt the PAS to the altered anatomy after OPHLs using fiberoptic endoscopic evaluation of swallowing (FEES) and to test its reliability. To adapt the PAS, two landmarks were identified: the entry of the laryngeal vestibule and the neoglottis. Ninety patients who underwent an OPHL were recruited (27 type I, 31 type II and 32 type III). FEES was performed and video-recorded. Two speech and language therapists (SLTs) independently rated each FEES using the PAS adapted for OPHL (OPHL-PAS). FEES recordings were rated for a second time by both SLTs at least 15 days from the first video analysis. Inter- and intra-rater agreement was assessed using unweighted Cohen's kappa. Overall, inter-rater agreement of the OPHL-PAS was k\u2009=\u20090.863, while intra-rater agreement was k\u2009=\u20090.854. Concerning different OPHL types, inter- and intra-rater agreement were k\u2009=\u20090.924 and k\u2009=\u20090.914 for type I, k\u2009=\u20090.865 and k\u2009=\u20090.790 for type II, and k\u2009=\u20090.808 and k\u2009=\u20090.858 for type III, respectively. The OPHL-PAS is a reliable scale to assess the invasion of lower airway during swallowing in patients with OPHL using FEES. The study represents the first attempt to define standard tools to assess swallowing functional outcome in this population

    Magna Graecia transcatheter aortic valve implantation registry: data on contrast medium osmolality and postprocedural acute kidney injury

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    A comprehensive description of baseline characteristics, procedural features and outcomes related to the development of acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) is reported in our research paper (Impact of contrast medium osmolality on the risk of acute kidney injury after transcatheter aortic valve implantation: insights from the Magna Graecia TAVI registry. Int J Cardiol. DOI: 10.1016/j.ijcard.2020.12.049). Three Italian heart centers were involved in this multicentric observational study. Between March 2011 and February 2019, a total of 888 patients underwent TAVI; according to the inclusion and exclusion criteria, 697 patients were included in the post-hoc analysis. This Data in Brief paper aims to report demographic, clinical, laboratory, echocardiographic, intraprocedural, periprocedural, postprocedural and follow-up data; all of them were prospectively collected from each patient's health record, whereas the analysis was performed retrospectively. Targets of this data analysis were: 1) to evaluate the impact of contrast medium (CM) osmolality on TAVI-related AKI; 2) to identify the most of risk factors involved in the development of such complication, and consequently in the occurrence of 1-year mortality; 3) to estimate the impact of CM osmolality on AKI in specific patient subgroups
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