4,979 research outputs found
j_psi Suppression and the Quark-Gluon Plasma
All measured Feynman x_f distributions of the ratio, R, of j_psi production
in nuclei relative to production on protons fall off with x_f.
They show [2] that absorption of charmonium cannot be the only source of
j_psi suppression and that energy loss of the constituents of the incident
proton prior to the j_psi production, because of the exponential sqrt(s)
dependence of the charmonium cross section, should not be neglected. Including
the effects of initial state energy loss we find that the latest measured
Pb-Pb j_psi cross sections do not provide any evidence for deconfinement.Comment: 9 pages, 2 figures, additional material, accepted by Physics Letter
When enough is more than enough. The hidden side of the cardiac effects of intense physical exercise
Ivabradine: a preliminary observation for a new terapeutic role in patients with multiple organ dysfunction syndrome
[No abstract available
Nonrepetitive Colourings of Planar Graphs with Colours
A vertex colouring of a graph is \emph{nonrepetitive} if there is no path for
which the first half of the path is assigned the same sequence of colours as
the second half. The \emph{nonrepetitive chromatic number} of a graph is
the minimum integer such that has a nonrepetitive -colouring.
Whether planar graphs have bounded nonrepetitive chromatic number is one of the
most important open problems in the field. Despite this, the best known upper
bound is for -vertex planar graphs. We prove a
upper bound
Design and control of a system for nanorobotics operating in low vacuum
Il lavoro presentato raccoglie e dimostra gli sforzi mirati alla realizzazione di un efficiente sistema in grado di abilitare l’uso di una piattaforma micro-robotica per micro e nano-manipolazioni all’interno di un ambiente estremamente confinato e controllato, il più possibile libero di impurità ed umidità. Con il fine ultimo di realizzare una apparecchiatura portatile ed economica sono stati fatti i primi passi per ottenere un sistema completo ed efficiente. Problematiche coinvolgenti molteplici domini sono stati affrontati a partire dalla progettazione meccanica fino al controllo computerizzato passando attraverso l’ottica e l’elettronica. È stata progettata una interfaccia meccanica che permettesse di mantenere il vuoto risolvendo i problemi esistenti. È stato studiato e proposto un sistema ottico di ingrandimento 500X a lunga focale per abilitare un controllo visivo dell’operatore durante le manipolazioni e per permettere un futuro controllo in “anello chiuso” tramite analisi delle immagini. Sono state operate modifiche alla elettronica di comando realizzando un sistema di amplificazione di segnale con il fine di rendere possibile un controllo computerizzato. Infine è stato realizzato il sistema di controllo ed attuazione in “anello aperto” tramite una opportuna interfaccia Matlab, rendendo possibile anche un più diretto ed intuitivo controllo tramite tastiera. Tutto il lavoro svolto ha permesso di ottenere una fine comando dei piezo-attuatori rendendo possibili interessanti manipolazione con microsfere di Nylon, tra i 50[µm] ed i 5[µm] e sottili film di Grafene
Amniotic fluid embolism pathophysiology suggests the new diagnostic armamentarium: β-tryptase and complement fractions C3-C4 are the indispensable working tools
Amniotic fluid embolism (AFE) is an uncommon obstetric condition involving pregnant women during labor or in the initial stages after delivery. Its incidence is estimated to be around 5.5 cases per 100,000 deliveries. Therefore, this paper investigated the pathophysiological mechanism, which underlies AFE, in order to evaluate the role of immune response in the development of this still enigmatic clinical entity. The following databases (from 1956 to September 2014) Medline, Cochrane Central, Scopus, Web of Science and Science Direct were used, searching the following key words: AFE, pathophysiology, immune/inflammatory response, complement and anaphylaxis. The main key word "AFE" was searched singularly and associated individually to each of the other keywords. Of the 146 sources found, only 19 were considered appropriate for the purpose of this paper. The clinical course is characterized by a rapid onset of symptoms, which include: acute hypotension and/or cardiac arrest, acute hypoxia (with dyspnoea, cyanosis and/or respiratory arrest), coagulopathies (disseminated intravascular coagulation and/or severe hemorrhage), coma and seizures. The pathology still determines a significant morbidity and mortality and potential permanent neurological sequelae for surviving patients. At this moment, numerous aspects involving the pathophysiology and clinical development are still not understood and several hypotheses have been formulated, in particular the possible role of anaphylaxis and complement. Moreover, the detection of serum tryptase and complement components and the evaluation of fetal antigens can explain several aspects of immune response
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