1,015 research outputs found
Satellite- and station-based climatology of low-level cloud cover during the long dry season in western Central Africa
Enhancing e-Infrastructures with Advanced Technical Computing: Parallel MATLAB® on the Grid
MATLAB® is widely used within the engineering and scientific fields as the language and environment for technical computing, while collaborative Grid computing on e-Infrastructures is used by scientific communities to deliver a faster time to solution. MATLAB allows users to express parallelism in their applications, and then execute code on multiprocessor environments such as large-scale e-Infrastructures. This paper demonstrates the integration of MATLAB and Grid technology with a representative implementation that uses gLite middleware to run parallel programs. Experimental results highlight the increases in productivity and performance that users obtain with MATLAB parallel computing on Grids
Un cas de brucellose canine à Brucella abortus
Une chienne, Berger des Pyrénées, vivant dans un élevage bovin, est trouvée porteuse de B. abortus, biotype I, sept mois après avoir avorté. L’infection de cette chienne et celle d’un taureau sont concomitantes. Cette observation permet de rappeler et résumer les principales publications qui montrent la grande importance des chiens comme vecteurs de la brucellose.A Berger des Pyrenees bitch, living in a farm, was found harboring B. abortus , biotype I, in a lymph node, seven months after abortion. The canine Brucella infection was coincidental to a bull brucellosis. This observation together with a summary of the available littérature help to recall the great importance of dogs as vectors of brucella infection
Diurnal to interannual variability of low‐level cloud cover over western equatorial Africa in May–October
This study examines the diurnal to interannual variations of the stratiform cloud cover in May–October (1971–2019) from a 3-hourly station database and from ERA5 reanalyses over western equatorial Africa (WEA). The main diurnal variations of the local-scale fraction and genus of stratiform clouds are synthesized into three canonical diurnal types (i.e., “clear,” “clear afternoon,” “cloudy” days). The interannual variations of frequencies of the three diurnal types during the cloudiest months (JJAS) are mostly associated with two main mechanisms: a meridional shallow overturning cell associating more “cloudy” and less “clear” and “clear afternoon” days to anomalous southerlies below 900 hPa over and around WEA, anomalous ascent around 5°–7°N, anomalous northerlies between 875 and 700 hPa, and anomalous subsidence over the equatorial Atlantic. This circulation is strongly related to interannual variations of the equatorial Atlantic upwelling (i.e., more clouds when the upwelling is strong) associated with a meridional shift of the Intertropical Convergence Zone over the Tropical Atlantic and adjacent continents. The second mechanism operates mostly in the zonal direction and involves again the coupled ocean–atmosphere system over the equatorial Atlantic, but also the remote El Niño–Southern Oscillation (ENSO). An anomalously cold equatorial Atlantic drives increased low-level westerlies toward the Congo Basin. Warm ENSO events promote broad warm and easterly anomalies in the middle and upper troposphere, which increase the local static stability, and thus the local stratiform cloud cover over WEA. The present study suggests new mechanisms responsible for interannual variations of stratiform clouds in WEA, thus providing avenues of future research regarding the stability of the stratiform cloud deck under the ongoing differential warming of tropical ocean and land masses
Tribochemistry of phosphorus additives: Experiments and first-principles calculations
Organophosphorus compounds are common additives included in liquid lubricants for many applications, in particular automotive applications. Typically, organic phosphites function as friction-modifiers whereas phosphates as anti-wear additives. While the antiwear action of phosphates is now well understood, the mechanism by which phosphites reduce friction is still not clear. Here we study the tribochemistry of both phosphites and phosphates using gas phase lubrication (GPL) and elucidate the microscopic mechanisms that lead to the better frictional properties of phosphites. In particular, by in situ spectroscopic analysis we show that the friction reduction is connected to the presence of iron phosphide, which is formed by tribochemical reactions involving phosphites. The functionality of elemental phosphorus in reducing the friction of iron-based interfaces is elucidated by first principle calculations. In particular, we show that the work of separation and shear strength of iron dramatically decrease by increasing the phosphorus concentration at the interface. These results suggest that the functionality of phosphites as friction modifiers may be related to the amount of elemental phosphorus that they can release at the tribological interface
Structure of TiAlN Reactive Sputtered Coatings
The Raman spectra, X-ray diffraction and hardness of the TiAlN films co-deposited on the steel substrates
by reactive sputtering from Ti and Al targets in a mixture of N2 + Ar gas with two magnetrons at
room temperature have been studied. From Raman spectra it is found that the position of high-frequency
bands in vibrational spectra was located at 700-730 cm 1 or in the region of 830 850 cm 1 depending on
the deposition parameters whereas it is not exceed 630 cm 1 from TiAlN of NaCl structure. It is found the
two-phase structure of coatings: a small quantity of NaCl-type structure of TiAlN (TiN) and the disordered
structure of the chains of polyhedra [TiNx] with x = 5 and x = 4. The chains of polyhedra [TiNx] with x = 4
are mainly formed at large discharge power of Al(Ti) target or at small content of N2 gas.
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Transmission congénitale de la brucellose bovine d’une génération à l’autre
Plommet M., Renoux G., Philippon Alain, Gestin J., Fenster-Bank R. Transmission congénitale de la brucellose bovine d’une génération à l’autre. In: Bulletin de l'Académie Vétérinaire de France tome 124 n°1, 1971. pp. 53-59
Zero Order Estimates for Analytic Functions
The primary goal of this paper is to provide a general multiplicity estimate.
Our main theorem allows to reduce a proof of multiplicity lemma to the study of
ideals stable under some appropriate transformation of a polynomial ring. In
particular, this result leads to a new link between the theory of polarized
algebraic dynamical systems and transcendental number theory. On the other
hand, it allows to establish an improvement of Nesterenko's conditional result
on solutions of systems of differential equations. We also deduce, under some
condition on stable varieties, the optimal multiplicity estimate in the case of
generalized Mahler's functional equations, previously studied by Mahler,
Nishioka, Topfer and others. Further, analyzing stable ideals we prove the
unconditional optimal result in the case of linear functional systems of
generalized Mahler's type. The latter result generalizes a famous theorem of
Nishioka (1986) previously conjectured by Mahler (1969), and simultaneously it
gives a counterpart in the case of functional systems for an important
unconditional result of Nesterenko (1977) concerning linear differential
systems. In summary, we provide a new universal tool for transcendental number
theory, applicable with fields of any characteristic. It opens the way to new
results on algebraic independence, as shown in Zorin (2010).Comment: 42 page
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