1,632 research outputs found

    Characterization of dust activity on Mars from MY27 to MY32 by PFS-MEX observations

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    We present spatial and temporal distributions of dust on Mars from Ls = 331 in MY26 until Ls = 80 in MY33 retrieved from the measurements taken by the Planetary Fourier Spectrometer (PFS) aboard Mars Express. In agreement with previous observations, large dust opacity is observed mostly in the southern hemisphere spring/summer and particularly over regions of higher terrain and large topographic variation. We present a comparison with dust opacities obtained from Thermal Emission Spectrometer (TES) - Mars Global Surveyor (MGS) measurements. We found good consistency between observations of two instruments during overlapping interval (Ls = 331 in MY26 until Ls = 77 in MY27). We found a different behavior of the dust opacity with latitude in the various Martian years (inter-annual variations). A global dust storm occurred in MY28. We observe a different spatial distribution, a later occurrence and dissipation of the dust maximum activity in MY28 than in other Martian years. A possible precursor signal to the global dust storm in MY 28 is observed at Ls = 200 - 235 especially over west Hellas. Heavy dust loads alter atmospheric temperatures. Due to the absorption of solar radiation and emission of infrared radiation to space by dust vertically non-uniformly distributed, a strong heating of high atmospheric levels (40 - 50 km) and cooling below around 30 km are observed.Comment: in press in Icarus. 47 pages, 15 figure

    Vehicular Inter-Networking via Named Data

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    In this paper we apply the Named Data Networking, a newly proposed Internet architecture, to networking vehicles on the run. Our initial design, dubbed V-NDN, illustrates NDN's promising potential in providing a unifying architecture that enables networking among all computing devices independent from whether they are connected through wired infrastructure, ad hoc, or intermittent DTN. This paper describes the prototype implementation of V-NDN and its preliminary performance assessment

    Design Method for Contra-Rotating Propellers for High-Speed Crafts: Revising the Original Lerbs Theory in a Modern Perspective

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    The main theoretical and numerical aspects of a design method for optimum contrar-rotating (CR) propellers for fast marine crafts are presented. We propose a reformulated version of a well-known design theory for contra-rotating propellers, by taking advantage of a new fully numerical algorithm for the calculation of the mutually induced velocities and introducing new features such as numerical lifting surface corrections, use of an integrated modern cavitation/strength criteria, a modified method to consider different numbers of blades among the two propellers, and to allow for an unloading function in the search for the optimal circulation distribution. The paper first introduces the main theoretical principles of the new methods and then discusses the influence of the main design parameters on an emblematic example of application in the case of counter rotating propellers for a pod propulsor designed for fast planing crafts (35 knots and above)

    An Attempted Suicide with Copper Sulphate injected intravenously:Pathopsysiology and Therapy about a case report

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    Acute copper sulphate poisoning is an unusual event, rarely following parenteral exposure, complicated by toxicological effects as haemolytic anaemia, methaemoglobinaemia , hepato-renal damage and acute rhabdomyolysis. Currently, the therapeutic management ignores unique classes of evidence and is mainly based on supportive and chelation therapies. Case details. This case report describes acute copper sulphate poisoning in a 37-year-old man who attempted suicide by self-injecting an unknown amount of copper sulphate. Within three days the patient developed severe intravascular haemolysis and rhabdomyolysis. Initial therapy relied on intensive supportive care with fluids administration, electrolyte correction and packed red blood cells transfusion. The D-penicillamine (30 mg/Kg/day per os) was prescribed as chelation therapy by the poison control centre. The N-acetilcysteine and ascorbic acid were administered to prevent further oxidative stress. Later on, two sessions of therapeutic plasma exchange were performed in order to support the drug therapy. Haemolysis and rhabdomyolysis reversed throughout the hospital stay. Discussion. In this case the antidotic and antioxidant therapy resulted effective to reverse haemolysis and rhabdomyolysis and to prevent hepatic and renal damage. Moreover, this case underlies that therapeutic plasma exchange should be considered as an additive measure to undertake since the earlier stages of the emergency intervention. Acute copper sulphate poisoning is an event complicated by toxicological effects: haemolytic anaemia, methaemoglobinaemia, hepato-renal damage, acute rhabdomyolysis. The therapeutic management ignores unique classes of evidence and is based on supportive and chelation therapies. In this case: i) the antidotic and antioxidant therapy resulted effective to reverse haemolysis and rhabdomyolysis and to prevent hepatic and renal damage, ii) therapeutic plasma exchange should be considered as an additive measure to undertake

    A case of infant botulism in a 4-month-old baby

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    This case-report highlights: i) the difficulty of IB diagnosis as it is a rare syndrome with subclinical onset, ii) the need for an accurate training for physicians involved in IB management, iii) the efficacy and safety of TEqA in IB treatment, iv) homemade honey is not the only cause of IB

    Level shifts and long memory: A state space approach

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    Short memory models contaminated by level shifts have similar long-memory features as fractionally integrated processes. This makes it hard to verify whether the true data generating process is a pure fractionally integrated process when employing standard estimation methods based on the autocorrelation function or the periodogram. In this paper, we propose a robust testing procedure, based on an encompassing parametric specification that allows us to disentangle the level shifts from the fractionally integrated component. The estimation is carried out on the basis of a state-space methodology and it leads to a robust estimate of the fractional integration parameter also in presence of level shifts. Once the memory parameter is correctly estimated, we use the KPSS test for presence of level shift. The Monte Carlo simulations show how this approach produces unbiased estimates of the memory parameter when shifts in the mean, or other slowly varying trends, are present in the data. Therefore, this subsequent robust version of the KPSS test for the presence of level shifts has proper size and by far the highest power compared to other existing tests. Finally, we illustrate the usefulness of the proposed approach on financial data, such as daily bipower variation and turnover

    The Impact of democratization : a preliminary investigation on social policies and political violence in Latin America

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    The recent strides of democracy in Latin America have been associated to conflicting outcomes. The expectation that democracy would bring about peace and prosperity have been only partly satisfied. While political violence has been by and large eradicated from the sub-continent, poverty and social injustice still prevail and hold sway. Our study argues that democracy matters for inequality through the growing strength of center left and left parties and by making political leaders in general more responsive to the underprivileged. Furthermore, although the pension reforms recently enacted in the region generated overall regressive outcomes on income distribution, democratic countries still benefit from their political past: where democratic tradition was stronger, such outcomes have been milder. Democratic tradition and the specific ideological connotations of the parties in power, on the other hand, did not play an equally crucial role in securing lower levels of political violence: during the last wave of democratizations in Latin America, domestic peace was rather an outcome of political and social concessions to those in distress. In sum, together with other factors and especially economic ones, the reason why recent democratizations have provided domestic peace in most cases, but have been unable so far to solve the problem of poverty and inequality, is that democratic traditions in the subcontinent have been relatively weak and, more specifically, that this weakness has undermined the growth of left and progressive parties, acting as an obstacle to redistribution. Such weakness, on the other hand, has not prevented the drastic reduction of domestic political violence, since what mattered in this case was a combination of symbolic or material concessions and political agreements among powerful élites and counter-élites
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