1,045 research outputs found
The Dark UNiverse Explorer (DUNE): Proposal to ESA's Cosmic Vision
The Dark UNiverse Explorer (DUNE) is a wide-field space imager whose primary
goal is the study of dark energy and dark matter with unprecedented precision.
For this purpose, DUNE is optimised for the measurement of weak gravitational
lensing but will also provide complementary measurements of baryonic accoustic
oscillations, cluster counts and the Integrated Sachs Wolfe effect. Immediate
auxiliary goals concern the evolution of galaxies, to be studied with
unequalled statistical power, the detailed structure of the Milky Way and
nearby galaxies, and the demographics of Earth-mass planets. DUNE is an
Medium-class mission which makes use of readily available components, heritage
from other missions, and synergy with ground based facilities to minimise cost
and risks. The payload consists of a 1.2m telescope with a combined visible/NIR
field-of-view of 1 deg^2. DUNE will carry out an all-sky survey, ranging from
550 to 1600nm, in one visible and three NIR bands which will form a unique
legacy for astronomy. DUNE will yield major advances in a broad range of fields
in astrophysics including fundamental cosmology, galaxy evolution, and
extrasolar planet search. DUNE was recently selected by ESA as one of the
mission concepts to be studied in its Cosmic Vision programme.Comment: Accepted in Experimental Astronom
Influence de la mortalité des cacaoyers sur la stabilité de la production dans une plantation industrielle
Effect of Cocoa Tree Mortality on Production Stability in a Private Estate. Yields in a 1,674 ha cocoa estate were analysed in Indonesia. The plantation, which was set up between 1981 and 1990 at Ransiki (Papua province), benefited from suitable soil and climatic conditions: good rainfall distribution and rich soils. The planting material comprised hybrids of various origins, Amelonados and local selections. Density measurements inside the plantation revealed a gradual reduction in the number of cocoa trees, from 1,250 at the outset to 835 trees/ha after 21 years. At the same time, overall yields for the same period remained stable. Cocoa tree mortality, which was responsible for the gradual reduction in density, did not affect production; neither did it alter the uniformity of the plant cover in the plots. This situation reflected an increase in tree productivity. The conditions for stabilized cocoa yields appeared to be linked not only to suitable edapho-climatic conditions and limited parasite pressure, but also to the ability of cocoa trees to increase their yields in conditions of decreasing stand due to the natural thining of the original plant population
Vimentin as a target for the treatment of COVID-19
We and others propose vimentin as a possible cellular target for the treatment of COVID-19. This innovative idea is so recent that it requires further attention and debate. The significant role played by vimentin in virus-induced infection however is well established: (1) vimentin has been reported as a co-receptor and/or attachment site for SARS-CoV; (2) vimentin is involved in viral replication in cells; (3) vimentin plays a fundamental role in both the viral infection and the consequent explosive immune-inflammatory response and (4) a lower vimentin expression is associated with the inhibition of epithelial to mesenchymal transition and fibrosis. Moreover, the absence of vimentin in mice makes them resistant to lung injury. Since vimentin has a twofold role in the disease, not only being involved in the viral infection but also in the associated life-threatening lung inflammation, the use of vimentin-targeted drugs may offer a synergistic advantage as compared with other treatments not targeting vimentin. Consequently, we speculate here that drugs which decrease the expression of vimentin can be used for the treatment of patients with COVID-19 and advise that several Food and Drug Administration-approved drugs be immediately tested in clinical trials against SARS-CoV-2, thus broadening therapeutic options for this type of viral infection
Experimental Study of Environment Friendly Mixed Refrigerant to Replace R-134a in a VCR System with Testing and Training of ANN
This work presents an experimental study on environment friendly mixed refrigerant to replace R134a in vapour compression refrigeration (VCR) System. The mixed refrigerants investigated are propane (R290), butane (R600), isobutene (R600a) and R134a. Even though the ozone depletion potentials of R134a relative to CFC-11 are very low; the global warming potentials are extremely high and also expensive. For this reason, the production and use of R134a will be terminated in the near future. Hydrocarbons are free from ozone depletion potential and have negligible global warming potential. The results showed that, mixed refrigerant with charge of 80 g satisfy the required freezer air temperature, when R134a with a charge of 110 g is used as refrigerant. The actual COP of refrigerator using mixed refrigerant was almost nearer that of the system using R134a as refrigerant. The coefficient of performance of the vapour compression refrigeration system using mixed refrigerant MR-3 [R134a/R290/ R600a/ R600 (20/35/40/5)] is having very close value with R134a and the Global warming potential of MR-3 is negligible when compared with R134a. Â Hence the mixed refrigerant MR-3 is chosen as an environmental friendly alternate refrigerant to R134a. Also the back propagation algorithm is implemented for training artificial neural network (ANN) to find out the optimum mixture having higher COP.Â
First microlensing candidate towards M31 from the Nainital Microlensing Survey
We report our first microlensing candidate NMS-E1 towards M31 from the data
accumulated during the four years of Nainital Microlensing Survey. Cousin R and
I band observations of ~13'x13' field in the direction of M31 have been carried
out since 1998 and data is analysed using the pixel technique proposed by the
AGAPE collaboration. NMS-E1 lies in the disk of M31 at \alpha = 0:43:33.3 and
\delta = +41:06:44, about 15.5 arcmin to the South-East direction of the center
of M31. The degenerate Paczy\'{n}ski fit gives a half intensity duration of ~59
days. The photometric analysis of the candidate shows that it reached R~20.1
mag at the time of maximum brightness and the colour of the source star was
estimated to be (R-I)_0 ~ 1.1 mag. The microlensing candidate is blended by red
variable stars; consequently the light curves do not strictly follow the
characteristic Paczy\'{n}ski shape and achromatic nature. However its long
period monitoring and similar behaviour in R and I bands supports its
microlensing nature.Comment: no changes except typos corrected, to appear in A&
Locally Perturbed Random Walks with Unbounded Jumps
In \cite{SzT}, D. Sz\'asz and A. Telcs have shown that for the diffusively
scaled, simple symmetric random walk, weak convergence to the Brownian motion
holds even in the case of local impurities if . The extension of their
result to finite range random walks is straightforward. Here, however, we are
interested in the situation when the random walk has unbounded range.
Concretely we generalize the statement of \cite{SzT} to unbounded random walks
whose jump distribution belongs to the domain of attraction of the normal law.
We do this first: for diffusively scaled random walks on having finite variance; and second: for random walks with distribution
belonging to the non-normal domain of attraction of the normal law. This result
can be applied to random walks with tail behavior analogous to that of the
infinite horizon Lorentz-process; these, in particular, have infinite variance,
and convergence to Brownian motion holds with the superdiffusive scaling.Comment: 16 page
Assessment of Negative Economic Impacts from Deer in the Northeastern United States
We conducted a survey and literature review to identify affected stakeholders and gauge economic impacts from unwanted deer-human interactions in the northeastern United States. We estimated an annual economic impact from deer-vehicle collisions and deer depredation to select high-value agricultural, grain, and nursery crops, and residential and commercial landscaping for 13 northeastern United States at nearly $640 million. Our results can be used by Extension and wildlife professionals to inform and involve stakeholders participating in deer management decisions, tailor management strategies to mitigate deer-human conflicts, and assist policy makers when weighing the benefits against the negative impacts from deer
Mass spectrometric gas composition measurements associated with jet interaction tests in a high-enthalpy wind tunnel
Knowledge of test gas composition is important in wind-tunnel experiments measuring aerothermodynamic interactions. This paper describes measurements made by sampling the top of the test section during runs of the Langley 7-Inch High-Temperature Tunnel. The tests were conducted to determine the mixing of gas injected from a flat-plate model into a combustion-heated hypervelocity test stream and to monitor the CO2 produced in the combustion. The Mass Spectrometric (MS) measurements yield the mole fraction of N2 or He and CO2 reaching the sample inlets. The data obtained for several tunnel run conditions are related to the pressures measured in the tunnel test section and at the MS ionizer inlet. The apparent distributions of injected gas species and tunnel gas (CO2) are discussed relative to the sampling techniques. The measurements provided significant real-time data for the distribution of injected gases in the test section. The jet N2 diffused readily from the test stream, but the jet He was mostly entrained. The amounts of CO2 and Ar diffusing upward in the test section for several run conditions indicated the variability of the combustion-gas test-stream composition
Cross-Over between universality classes in a magnetically disordered metallic wire
In this article we present numerical results of conduction in a disordered
quasi-1D wire in the possible presence of magnetic impurities. Our analysis
leads us to the study of universal properties in different conduction regimes
such as the localized and metallic ones. In particular, we analyse the
cross-over between universality classes occurring when the strength of magnetic
disorder is increased. For this purpose, we use a numerical Landauer approach,
and derive the scattering matrix of the wire from electron's Green's function.Comment: Final version, accepted for publication in New Journ. of Physics, 27
pages, 28 figures. Replaces the earlier shorter preprint arXiv:0910.427
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