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Search Results: 1 - 10 of 219572 matches for " C. Belotti "
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Technical Note: Regularization performances with the error consistency method in the case of retrieved atmospheric profiles
S. Ceccherini, C. Belotti, B. Carli, P. Raspollini,M. Ridolfi
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2007,
Abstract: The retrieval of concentration vertical profiles of atmospheric constituents from spectroscopic measurements is often an ill-conditioned problem and regularization methods are frequently used to improve its stability. Recently a new method, that provides a good compromise between precision and vertical resolution, was proposed to determine analytically the value of the regularization parameter. This method is applied for the first time to real measurements with its implementation in the operational retrieval code of the satellite limb-emission measurements of the MIPAS instrument and its performances are quantitatively analyzed. The adopted regularization improves the stability of the retrieval providing smooth profiles without major degradation of the vertical resolution. In the analyzed measurements the retrieval procedure provides a vertical resolution that, in the troposphere and low stratosphere, is smaller than the vertical field of view of the instrument.
Technical Note: Regularization performances with the error consistency method in the case of retrieved atmospheric profiles
S. Ceccherini,C. Belotti,B. Carli,P. Raspollini
Atmospheric Chemistry and Physics Discussions , 2006,
Abstract: The retrieval of concentration vertical profiles of atmospheric constituents from spectroscopic measurements is often an ill-conditioned problem and regularization methods are frequently used to improve its stability. Recently a new method, that provides a good compromise between precision and vertical resolution, was proposed to determine analytically the value of the regularization parameter. This method is applied for the first time to real measurements with its implementation in the operational retrieval code of the satellite limb-emission measurements of the MIPAS instrument and its performances are quantitatively analyzed. The adopted regularization improves the stability of the retrieval providing smooth profiles without major degradation of the vertical resolution. In the analyzed measurements the retrieval procedure provides a vertical resolution that, in the troposphere and low stratosphere, is smaller than the vertical field of view of the instrument.
First spectral measurement of the Earth's upwelling emission using an uncooled wideband Fourier transform spectrometer
L. Palchetti,C. Belotti,G. Bianchini,F. Castagnoli
Atmospheric Chemistry and Physics Discussions , 2006,
Abstract: The first spectral measurement of Earth's emitted radiation to space in the wideband range from 100 to 1400 cm 1 with 0.5 cm 1 spectral resolution is presented. The measurement was performed from a stratospheric balloon in tropical region using a Fourier transform spectrometer, during a field campaign held in Brazil in June 2005. The instrument, which has uncooled components including the detector module, is a prototype developed as part of the study for the REFIR (Radiation Explorer in the Far InfraRed) space mission. This paper shows the results of the field campaign with particular attention to the measurement capabilities of the prototype. The results are compared with measurements taken by IASI-balloon (Infrared Atmospheric Sounding Interferometer – Balloon version), aboard the same platform, and with forward model estimations. The infrared signature of clouds is observed in the measurements.
MIPAS level 2 operational analysis
P. Raspollini,C. Belotti,A. Burgess,B. Carli
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2006,
Abstract: The MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) instrument has been operating on-board the ENVISAT satellite since March 2002. In the first two years, it acquired in a nearly continuous manner high resolution (0.025 cm 1 unapodized) emission spectra of the Earth's atmosphere at limb in the middle infrared region. This paper describes the level 2 near real-time (NRT) and off-line (OL) ESA processors that have been used to derive level 2 geophysical products from the calibrated and geolocated level 1b spectra. The design of the code and the analysis methodology have been driven by the requirements for NRT processing. This paper reviews the performance of the optimized retrieval strategy that has been implemented to achieve these requirements and provides estimated error budgets for the target products: pressure, temperature, O3, H2O, CH4, HNO3, N2O and NO2, in the altitude measurement range from 6 to 68 km. From application to real MIPAS data, it was found that no change was needed in the developed code although an external algorithm was introduced to identify clouds with high opacity and to exclude affected spectra from the analysis. In addition, a number of updates were made to the set-up parameters and to auxiliary data. In particular, a new version of the MIPAS dedicated spectroscopic database was used and, in the OL analysis, the retrieval range was extended to reduce errors due to uncertainties in extrapolation of the profile outside the retrieval range and more stringent convergence criteria were implemented. A statistical analysis on the χ2 values obtained in one year of measurements shows good agreement with the a priori estimate of the forward model errors. On the basis of the first two years of MIPAS measurements the estimates of the forward model and instrument errors are in general found to be conservative with excellent performance demonstrated for frequency calibration. It is noted that the total retrieval error is limited by forward model errors which make effectless a further reduction of random errors. However, such a reduction is within the capabilities of MIPAS measurements, which contain many more spectral signatures of the target species than what has currently been used. Further work is needed to reduce the amplitude of the forward model errors, so that the random error and the total error budget can be reduced accordingly. The importance of the Averaging kernels for a full characterization of the target products is underlined and the equations are provided for their practical applications.
Technical note: First spectral measurement of the Earth's upwelling emission using an uncooled wideband Fourier transform spectrometer
L. Palchetti, C. Belotti, G. Bianchini, F. Castagnoli, B. Carli, U. Cortesi, M. Pellegrini, C. Camy-Peyret, P. Jeseck,Y. Té
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2006,
Abstract: The first spectral measurement of Earth's emitted radiation to space in the wideband range from 100 to 1400 cm 1 with 0.5 cm 1 spectral resolution is presented. The measurement was performed from a stratospheric balloon in tropical region using a Fourier transform spectrometer, during a field campaign held in Brazil in June 2005. The instrument, which has uncooled components including the detector module, is a prototype developed as part of the study for the REFIR (Radiation Explorer in the Far InfraRed) space mission. This paper shows the results of the field campaign with particular attention to the measurement capabilities of the prototype. The results are compared with measurements taken by IASI-balloon (Infrared Atmospheric Sounding Interferometer – Balloon version), aboard the same platform, and with forward model estimations. The infrared signature of clouds is observed in the measurements.
En companía de los muertos: Ofrendas de animales en los cementerios de La Isla (Tilcara, Jujuy)
Belotti López de Medina,Carlos R;
Intersecciones en antropolog?-a , 2012,
Abstract: this paper presents an exhaustive analysis of the faunal remains recovered by debenedetti from burials 6, 10 and 11 from el morro cemetery at la isla de tilcara site, jujuy, argentina. there is a notable consensus about the importance of el morro, since its burials contain no more than one or two individuals along with numerous offerings, some of them clearly sumptuary. in some of these tombs, among the diverse items, archaeofaunal remains were found that can be safely identified as sacrificed animals. the zooarchaeological analysis presented here was carried out on two of those offerings: the cranium and mandibles of a small to medium sized dog, estimated to be seven months old, found in burial 6, and a faunal assemblage from burial 11, among which an almost complete macaw skeleton was identified, similar in size to ara chloroptera. the mandibles of a small felid, estimated to be over six months old, from burial 10 were also identified. the main goal of the analysis was to produce relevant information about the taxonomy and age of death of these remains. with the results in mind, some plausible explanations about the place of animals in the funeral rites at burials 6, 10, and 11 and hypothesis about the social role of the people buried there are offered.
En companía de los muertos: Ofrendas de animales en los cementerios de La Isla (Tilcara, Jujuy) In the company of the dead: Animal offerings at the cemeteries of La Isla, Tilcara, Jujuy
Carlos R Belotti López de Medina
Intersecciones en Antropología , 2012,
Abstract: Presentamos aquí la identificación de los conjuntos arqueofaunísticos recuperados por Debenedetti en tres entierros de la necrópolis El Morro, del sitio La Isla de Tilcara (Jujuy, Argentina). Hay un consenso notable en torno a la peculiaridad de este cementerio, caracterizado por inhumaciones simples o dobles acompanadas de numerosas ofrendas, algunas de ellas suntuarias. Nuestro trabajo se organizó en torno a dos objetivos. Primero, la identificación taxonómica y etaria de los hallazgos. Se caracterizaron: 1) un cráneo y mandíbula de perro hallados en la Tumba 6, con una edad estimada superior a los siete meses; 2) los restos faunísticos de la Tumba 11, entre ellos el esqueleto casi completo de un guacamayo adulto, en el rango de tama o del Ara chloroptera. 3) una mandíbula de félido pequeno de la Tumba 10, con una edad estimada superior a los seis meses. En el informe de Debenedetti los dos primeros conjuntos se reportan como esqueletos completos, lo que permite identificarlos como sacrificios. Nuestro segundo objetivo fue formular algunas interpretaciones plausibles sobre el contenido de las tumbas y el lugar de los animales en los ritos mortuorios. This paper presents an exhaustive analysis of the faunal remains recovered by Debenedetti from burials 6, 10 and 11 from El Morro cemetery at La Isla de Tilcara site, Jujuy, Argentina. There is a notable consensus about the importance of El Morro, since its burials contain no more than one or two individuals along with numerous offerings, some of them clearly sumptuary. In some of these tombs, among the diverse items, archaeofaunal remains were found that can be safely identified as sacrificed animals. The zooarchaeological analysis presented here was carried out on two of those offerings: the cranium and mandibles of a small to medium sized dog, estimated to be seven months old, found in Burial 6, and a faunal assemblage from Burial 11, among which an almost complete macaw skeleton was identified, similar in size to Ara chloroptera. The mandibles of a small felid, estimated to be over six months old, from Burial 10 were also identified. The main goal of the analysis was to produce relevant information about the taxonomy and age of death of these remains. With the results in mind, some plausible explanations about the place of animals in the funeral rites at Burials 6, 10, and 11 and hypothesis about the social role of the people buried there are offered.
Effect of Nitrogen and Phosphorus Starvations on Chlorella vulgaris Lipids Productivity and Quality under Different Trophic Regimens for Biodiesel Production  [PDF]
Gianluca Belotti, Marco Bravi, Benedetta de Caprariis, Paolo de Filippis, Marco Scarsella
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.412A2006
Abstract:

In this work the effects of nutrients starvations on Chlorella vulgaris were investigated in different trophic regimens. For all the tested conditions, the cellular response to nutrient starvation and trophic regimen was evaluated on specific growth rate, biomass and lipids productivity, lipids content and quality. These parameters are all crucial for microalgae biodiesel production, but in literature the lipids quality, in terms of polar and nonpolar lipids, is often neglected. Thus the typical high content of polar lipids, a class of molecules that negatively affects the biodiesel production process, of microalgae crude oil is generally not analyzed. In the tested conditions the triggering effect of nitrogen starvation on total lipids productivity is confirmed only in autotrophic regimen, while in mixotrophic and heterotrophic conditions the total lipids productivity is reduced, as a consequence of the lowered biomass productivity, but with an evident compositional shift towards nonpolar lipids production (from 0.5 mg/Ld to 41.6 mg/Ld in mixotrophic regimen). Nitrogen and phosphorus co-starvation induced the highest nonpolar lipids productivity in all trophic regimens. Maximum nonpolar lipids productivity was obtained in nitrogen limited and phosphorus deprived condition during mixotrophic growth, equal to 118.2 mg/Ld, representing the 80% of produced lipids. On the basis of the obtained results, the possibility of a short pre-harvesting cultural step to maximize the nonpolar lipids yield of the crop could be envisaged.

A local branching heuristic for MINLPs
Giacomo Nannicini,Pietro Belotti,Leo Liberti
Mathematics , 2008,
Abstract: Local branching is an improvement heuristic, developed within the context of branch-and-bound algorithms for MILPs, which has proved to be very effective in practice. For the binary case, it is based on defining a neighbourhood of the current incumbent solution by allowing only a few binary variables to flip their value, through the addition of a local branching constraint. The neighbourhood is then explored with a branch-and-bound solver. We propose a local branching scheme for (nonconvex) MINLPs which is based on iteratively solving MILPs and NLPs. Preliminary computational experiments show that this approach is able to improve the incumbent solution on the majority of the test instances, requiring only a short CPU time. Moreover, we provide algorithmic ideas for a primal heuristic whose purpose is to find a first feasible solution, based on the same scheme.
Efficient storage of Pareto points in biobjective mixed integer programming
Nathan Adelgren,Pietro Belotti,Akshay Gupte
Mathematics , 2014,
Abstract: Biobjective mixed integer linear programs (BOMILP) are optimization problems where two linear objectives are optimized over a polyhedron while restricting some of the variables to be integer. Since many of the techniques for solving BOMILP (or approximating its solution set) are iterative processes which utilize data discovered during early iterations to aid in the discovery of improved data during later iterations, it is highly desirable to efficiently store the nondominated subset of a given set of data. This problem has not received considerable attention in the context of BOMILP; only naive methods have been implemented. We seek to bridge this gap by presenting a new data structure in the form of a modified binary tree that stores, updates, searches and returns nondominated solutions. This structure takes points and line segments in $\mathbb{R}^2$ as input and stores the nondominated subset of this input. We note that when used alongside an exact solution procedure, such as branch-and-bound (BB), at termination the data stored by this structure is precisely the set of Pareto optimal solutions. We perform two experiments. The first is designed to compare the utility of our structure for storing nondominated data to that of a dynamic list which updates via pairwise comparison. In the second we use our data structure alongside the biobjective BB techniques available in the literature and solve specific instances of BOMILP. The results of our first experiment suggest that the data structure performs reasonably well in handling input of up to $10^7$ points or segments and does so much more efficiently than a dynamic list. The results of the second experiment show that when our structure is utilized alongside BB fathoming is enhanced and running times improve slightly.
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