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Search Results: 1 - 10 of 68 matches for " Spoto "
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Shadowing Lemma and Chaotic Orbit Determination
Federica Spoto,Andrea Milani
Mathematics , 2015,
Abstract: Orbit determination is possible for a chaotic orbit of a dynamical system, given a finite set of observations, provided the initial conditions are at the central time. In a simple discrete model, the standard map, we tackle the problem of chaotic orbit determination when observations extend beyond the predictability horizon. If the orbit is hyperbolic, a shadowing orbit is computed by the least squares orbit determination. We test both the convergence of the orbit determination iterative procedure and the behaviour of the uncertainties as a function of the maximum number $n$ of map iterations observed. When the initial conditions belong to a chaotic orbit, the orbit determination is made impossible by numerical instability beyond a computability horizon, which can be approximately predicted by a simple formula. Moreover, the uncertainty of the results is sharply increased if a dynamical parameter is added to the initial conditions as parameter to be estimated. The uncertainty of the dynamical parameter decreases like $n^a$ with $a<0$ but not large (of the order of unity). If only the initial conditions are estimated, their uncertainty decreases exponentially with $n$. If they belong to a non-chaotic orbit the computational horizon is much larger, if it exists at all, and the decrease of the uncertainty is polynomial in all parameters, like $n^a$ with $a\simeq 1/2$. The Shadowing Lemma does not dictate what the asymptotic behaviour of the uncertainties should be. These phenomena have significant implications, which remain to be studied, in practical problems of orbit determination involving chaos, such as the chaotic rotation state of a celestial body and a chaotic orbit of a planet-crossing asteroid undergoing many close approaches.
Isothermal Amplification Methods for the Detection of Nucleic Acids in Microfluidic Devices
Laura Maria Zanoli,Giuseppe Spoto
Biosensors , 2013, DOI: 10.3390/bios3010018
Abstract: Diagnostic tools for biomolecular detection need to fulfill specific requirements in terms of sensitivity, selectivity and high-throughput in order to widen their applicability and to minimize the cost of the assay. The nucleic acid amplification is a key step in DNA detection assays. It contributes to improving the assay sensitivity by enabling the detection of a limited number of target molecules. The use of microfluidic devices to miniaturize amplification protocols reduces the required sample volume and the analysis times and offers new possibilities for the process automation and integration in one single device. The vast majority of miniaturized systems for nucleic acid analysis exploit the polymerase chain reaction (PCR) amplification method, which requires repeated cycles of three or two temperature-dependent steps during the amplification of the nucleic acid target sequence. In contrast, low temperature isothermal amplification methods have no need for thermal cycling thus requiring simplified microfluidic device features. Here, the use of miniaturized analysis systems using isothermal amplification reactions for the nucleic acid amplification will be discussed.
Deriving Escape Analysis by Abstract Interpretation: Proofs of results
Patricia M. Hill,Fausto Spoto
Computer Science , 2006,
Abstract: Escape analysis of object-oriented languages approximates the set of objects which do not escape from a given context. If we take a method as context, the non-escaping objects can be allocated on its activation stack; if we take a thread, Java synchronisation locks on such objects are not needed. In this paper, we formalise a basic escape domain e as an abstract interpretation of concrete states, which we then refine into an abstract domain er which is more concrete than e and, hence, leads to a more precise escape analysis than e. We provide optimality results for both e and er, in the form of Galois insertions from the concrete to the abstract domains and of optimal abstract operations. The Galois insertion property is obtained by restricting the abstract domains to those elements which do not contain garbage, by using an abstract garbage collector. Our implementation of er is hence an implementation of a formally correct escape analyser, able to detect the stack allocatable creation points of Java (bytecode) applications. This report contains the proofs of results of a paper with the same title and authors and to be published in the Journal "Higher-Order Symbolic Computation".
Asteroid family ages
Federica Spoto,Andrea Milani,Zoran Knezevic
Physics , 2015, DOI: 10.1016/j.icarus.2015.04.041
Abstract: A new family classification, based on a catalog of proper elements with $\sim 384,000$ numbered asteroids and on new methods is available. For the $45$ dynamical families with $>250$ members identified in this classification, we present an attempt to obtain statistically significant ages: we succeeded in computing ages for $37$ collisional families. We used a rigorous method, including a least squares fit of the two sides of a V-shape plot in the proper semimajor axis, inverse diameter plane to determine the corresponding slopes, an advanced error model for the uncertainties of asteroid diameters, an iterative outlier rejection scheme and quality control. The best available Yarkovsky measurement was used to estimate a calibration of the Yarkovsky effect for each family. The results are presented separately for the families originated in fragmentation or cratering events, for the young, compact families and for the truncated, one-sided families. For all the computed ages the corresponding uncertainties are provided. We found 2 cases where two separate dynamical families form together a single V-shape with compatible slopes, thus indicating a single collisional event. We have also found 3 examples of dynamical families containing multiple collisional families, plus a dubious case. We have found 2 cases of families containing a conspicuous subfamily, such that it is possible to measure the slope of a distinct V-shape, thus the age of the secondary collision. We also provide data on the central gaps appearing in some families. The ages computed in this paper are obtained with a single and uniform methodology, thus the ages of different families can be compared, providing a first example of collisional chronology of the asteroid main belt.
Non-Termination Analysis of Java Bytecode
étienne Payet,Fred Mesnard,Fausto Spoto
Computer Science , 2014,
Abstract: We introduce a fully automated static analysis that takes a sequential Java bytecode program P as input and attempts to prove that there exists an infinite execution of P. The technique consists in compiling P into a constraint logic program P_CLP and in proving non-termination of P_CLP; when P consists of instructions that are exactly compiled into constraints, the non-termination of P_CLP entails that of P. Our approach can handle method calls; to the best of our knowledge, it is the first static approach for Java bytecode able to prove the existence of infinite recursions. We have implemented our technique inside the Julia analyser. We have compared the results of Julia on a set of 113 programs with those provided by AProVE and Invel, the only freely usable non-termination analysers comparable to ours that we are aware of. Only Julia could detect non-termination due to infinite recursion.
Influência de sanificantes nas características físicas e químicas de uva Itália
Albertini, Silvana;Miguel, Ana Carolina Almeida;Spoto, Marta Helena Fillet;
Ciência e Tecnologia de Alimentos , 2009, DOI: 10.1590/S0101-20612009000300007
Abstract: the objective of this work was to evaluate the influence of sodium dichloroisocianurate (nadcc), ethylic alcohol, and sodium hypochlorite sanitizers, on the quality of 'itália' grape, based on the physical and chemical characteristics. clusters of 'itália' grape harvested in s?o miguel arcanjo (sp) were selected by size and quality and submitted the postharvest treatments by immersion in ethylic alcohol solution (15% v/v), sodium dichloroisocianurate (200 ppm), and sodium hypochlorite (200 ppm) for 3 seconds and 10 minutes, respectively under ambient room conditions (21.2 °c; 69.8% hr) for 9 days. the clusters weight loss, tax of degrane, coloration, firmness, contents of soluble solids (ss), and titratable acidity (ta), ss/ta relation and ph of the berries were evaluated every three days. under those conditions, the highest daily average mass loss was found in the sodium hypochlorite (0.7333%/day) followed by the non- sanitized clusters (0.6163%/day), sodium dichloroisocianurate (0.5837%/day), and ethylic alcohol (0.5623%/day). the berries sanitized with sodium dichloroisocianurate were darker and yellow. the sanification differences regarding firmness, ph, contents of soluble solids and titratable acidity, and ss/ta relation were not verified. from the results it can be concluded that the sanitizers do not influence in the physical and chemical qualities of 'itália' grape.
Cinética da degrada??o de geleiada de morango
Miguel, Ana Carolina Almeida;Albertini, Silvana;Spoto, Marta Helena Fillet;
Ciência e Tecnologia de Alimentos , 2009, DOI: 10.1590/S0101-20612009000100022
Abstract: strawberry jelly was stored at 20 (control), 30 (room) and 40 (accelerated) oc in order to evaluate their shelf lives. the shelf-life evaluation was based on objective color readings of l a b hunter color (minolta chroma meter cr-400) and on subjective color methods, smell, flavor, and texture (quantitative descriptive analysis) measurements. objective and subjective analyses were carried out for 180 days at 30-day intervals under three different conditions. experimental data show that the color degradation followed the model of a first order kinetic reaction. the arrhenius model was applied to the reaction rates (k) at each temperature obtaining activation energy (ea) of 5.66 kcal.mol-1 and a q10 of 1.36. the jellies showed adequate quality with relation to acid ascorbic content in the occasion of the processing, but they had presented low vitamin c retention. on the 60th day, the vitamin c content reduced more than 98%, regardless of the storage condition. the jellies stored at 40 oc proved more sensitive to the alterations in the color, and such temperature affected negatively the sensory attributes indicated by the browning and losses of smell, flavor, and texture. the results suggest that strawberry jellies must be stored under controlled conditions of temperature (20 to 30 oc).
Efeito da radia??o gama sobre o perfil sensorial de suco de laranja
Verruma-Bernardi, Marta Regina;Spoto, Marta Helena F.;
Ciência e Tecnologia de Alimentos , 2003, DOI: 10.1590/S0101-20612003000100007
Abstract: the objective of this work was to evaluate the characteristics of the irradiated fresh of 'pera' sweet orange (citrus sinnensis l.) juice and kept refrigerated. samples of orange juice (control) and samples irradiated with 1.5 and 3.0kgy per hour (cobalt 60) were stored for 1, 7, 14 and 21 days at 4oc. quantitative descriptive analysis was conducted by a selected trained panels that evaluated appearance, aroma, flavor and texture of juices. radiation levels affected appearance characteristics as color, shine and gummy. irradiated juice resulted more clear and shinny and less gummy, more cooked, with past and artificial aroma, more acid, bitter, cooked, sap, past and with accentuated artificial orange than the control. irradiation levels affected texture characteristics as body and astringency, homogeneity attribute was not affected. color and gummy of control sample intensified with the increase of storage periods. results lead juice irradiation promoted negatively on sensorial characteristic.
Estádios de matura??o e qualidade pós-colheita de goiabas 'Pedro Sato'
Azzolini, Marisa;Jacomino, Angelo Pedro;Spoto, Marta Helena Fillete;
Revista Brasileira de Fruticultura , 2004, DOI: 10.1590/S0100-29452004000100009
Abstract: the objective of this work was to evaluate the influence of the maturation stages in the postharvest quality of 'pedro sato' guavas (psidium guajava l.). the fruits were harvested in three maturation stages, based on the skin color , (stage 1- dark green: stage 2- light green and stage 3- yellowish green) and stored at 25±1 oc and 85±5% relative umidity. at the harvest, the three maturation stages presented distinct results to skin color, pulp firmness and relationship total soluble solids/total acydity (tss/ta). the maximum market life period was six, four and two days after the harvest for the stages 1, 2 and 3, respectively. at the end of this period, the fruits harvested at stage 1 showed the skin color greener (ho>101.55), major acidity and minor ratio tss/ta than the other stages. the fruits harvested on the 2 and 3 stages did not show differences in the physico-chemical characteristics at the end of the market life period, but they show differences in the sensorial quality, where the fruits harvested at the stage 3 were better than the others.
Edible mushroom Pleurotus sajor-caju production on washed and supplemented sugarcane bagasse
Moda, Evelise Moncaio;Horii, Jorge;Spoto, Marta Helena Fillet;
Scientia Agricola , 2005, DOI: 10.1590/S0103-90162005000200006
Abstract: traditionally, the cultivation of pleurotus sajor-caju is performed on different composted and pasteurized agricultural residues. the objective of this study was to investigate whether traditional composting and pasteurization processes could be replaced by washed and supplemented (mineral or organic) sugarcane bagasse. in one experiment, fresh sugarcane bagasse was immersed in hot water at 80°c for two hours (control) or washed in fresh water for one hour using an adapted machine for residue treatment. in another experiment, fresh sugarcane bagasse was washed in fresh water (control), and supplemented with corn grits (organic supplementation), or supplemented with nutrient solution (mineral supplementation). in the first experiment, the washed bagasse presented a average biological efficiency (abe) of 19.16% with 44% contamination, and the pasteurized bagasse presented a abe of 13.86% with 70% contamination. in the second experiment, corn grits presented the poorest performance, with a abe of 15.66% and 60% contamination, while supplementation with the nutrient solution presented a abe of 30.03%, whereas the control of 26.62%. washing fresh sugarcane bagasse could suppress the pasteurized substrate in pleurotus sajor-caju production, compensating a reduced abe with a faster process.
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