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Search Results: 1 - 10 of 16041 matches for " Marco Barbieri "
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Effects of frequency correlation in linear optical entangling gate operated with independent photons
Marco Barbieri
Physics , 2007, DOI: 10.1103/PhysRevA.76.043825
Abstract: Bose-Einstein coalescence of independent photons at the surface of a beam splitter is the physical process that allows linear optical quantum gates to be built. When distinct parametric down-conversion events are used as an independent photon source, distinguishability arises form the energy correlation of each photon with its twin. We find that increasing the pump bandwidth may help in improving the visibility of non-classical interference and reaching a level of near perfect indistinguishability. PACS: 03.67.Mn, 42.65.Lm, 42.50.St.
A Dynamical Model of Genetic Networks for Cell Differentiation
Marco Villani,Alessia Barbieri,Roberto Serra
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017703
Abstract: A mathematical model is proposed which is able to describe the most important features of cell differentiation, without requiring specific detailed assumptions concerning the interactions which drive the phenomenon. On the contrary, cell differentiation is described here as an emergent property of a generic model of the underlying gene regulatory network, and it can therefore be applied to a variety of different organisms. The model points to a peculiar role of cellular noise in differentiation and leads to non trivial predictions which could be subject to experimental testing. Moreover, a single model proves able to describe several different phenomena observed in various differentiation processes.
Multipartite optomechanical entanglement from competing nonlinearities
André Xuereb,Marco Barbieri,Mauro Paternostro
Physics , 2012, DOI: 10.1103/PhysRevA.86.013809
Abstract: We investigate the nature of the three-mode interaction inside an optomechanically-active microtoroid with a sizeable chi^(2) coefficient. Experimental techniques are quickly advancing to the point where structures with the necessary properties can be made, and we argue that these provide a natural setting in which to observe rich dynamics leading, for instance, to genuine tripartite steady-state entanglement. We also show that this approach lends itself to a full characterisation of the three-mode state of the system.
An educational path for the magnetic vector potential and its physical implications
Sara Barbieri,Michela Cavinato,Marco Giliberti
Physics , 2013, DOI: 10.1088/0143-0807/35/2/029501
Abstract: We present an educational path on the magnetic vector potential A addressed to undergraduate students and to pre-service physics teachers. Starting from the generalized Ampere-Laplace law, in the framework of a slowly varying time-dependent field approximation, the magnetic vector potential is written in terms of its empirical referent, i. e. the conduction current. Therefore, once the currents are known, our approach allows a clear and univocal physical determination of A overcoming the mathematical indeterminacy due to the gauge transformations. We have no need to fix a gauge, since for slowly varying time-dependent electric and magnetic fields, the natural gauge for A is the Coulomb one. We stress the difference between our approach and those usually presented in the literature. Finally, a physical interpretation of the magnetic vector potential is discussed and some examples of calculation of A are analysed.
Metrology with Unknown Detectors
Matteo Altorio,Marco G. Genoni,Fabrizia Somma,Marco Barbieri
Physics , 2015,
Abstract: The best possible precision is one of the key figures in metrology, but this is established by the exact response of the detection apparatus, which is often unknown. There exist techniques for detector characterisation, that have been introduced in the context of quantum technologies, but apply as well for ordinary classical coherence; these techniques, though, rely on intense data processing. Here we show that one can make use of the simpler approach of data fitting patterns in order to obtain an estimate of the Cram\'er-Rao bound allowed by an unknown detector, and present applications in polarimetry. Further, we show how this formalism provide a useful calculation tool in an estimation problem involving a continuous-variable quantum state, i.e. a quantum harmonic oscillator.
Infant mortality rates according to socioeconomic status in a Brazilian city
Goldani,Marcelo Zubaran; Barbieri,Marco Antonio; Bettiol,Heloisa; Barbieri,Marisa Ramos; Tomkins,Andrew;
Revista de Saúde Pública , 2001, DOI: 10.1590/S0034-89102001000300007
Abstract: objective: data from municipal databases can be used to plan interventions aimed at reducing inequities in health care. the objective of the study was to determine the distribution of infant mortality according to an urban geoeconomic classification using routinely collected municipal data. methods: all live births (total of 42,381) and infant deaths (total of 731) that occurred between 1994 and 1998 in ribeir?o preto, brazil, were considered. four different geoeconomic areas were defined according to the family head's income in each administrative urban zone. results: the trends for infant mortality rate and its different components, neonatal mortality rate and post-neonatal mortality rate, decreased in ribeir?o preto from 1994 to 1998 (chi-square for trend, p<0.05). these rates were inversely correlated with the distribution of lower salaries in the geoeconomic areas (less than 5 minimum wages per family head), in particular the post-neonatal mortality rate (chi-square for trend, p<0.05). finally, the poor area showed a steady increase in excess infant mortality. conclusions: the results indicate that infant mortality rates are associated with social inequality and can be monitored using municipal databases. the findings also suggest an increase in the impact of social inequality on infant health in ribeir?o preto, especially in the poor area. the monitoring of health inequalities using municipal databases may be an increasingly more useful tool given the continuous decentralization of health management at the municipal level in brazil.
Infant mortality rates according to socioeconomic status in a Brazilian city
Goldani Marcelo Zubaran,Barbieri Marco Antonio,Bettiol Heloisa,Barbieri Marisa Ramos
Revista de Saúde Pública , 2001,
Abstract: OBJECTIVE: Data from municipal databases can be used to plan interventions aimed at reducing inequities in health care. The objective of the study was to determine the distribution of infant mortality according to an urban geoeconomic classification using routinely collected municipal data. METHODS: All live births (total of 42,381) and infant deaths (total of 731) that occurred between 1994 and 1998 in Ribeir o Preto, Brazil, were considered. Four different geoeconomic areas were defined according to the family head's income in each administrative urban zone. RESULTS: The trends for infant mortality rate and its different components, neonatal mortality rate and post-neonatal mortality rate, decreased in Ribeir o Preto from 1994 to 1998 (chi-square for trend, p<0.05). These rates were inversely correlated with the distribution of lower salaries in the geoeconomic areas (less than 5 minimum wages per family head), in particular the post-neonatal mortality rate (chi-square for trend, p<0.05). Finally, the poor area showed a steady increase in excess infant mortality. CONCLUSIONS: The results indicate that infant mortality rates are associated with social inequality and can be monitored using municipal databases. The findings also suggest an increase in the impact of social inequality on infant health in Ribeir o Preto, especially in the poor area. The monitoring of health inequalities using municipal databases may be an increasingly more useful tool given the continuous decentralization of health management at the municipal level in Brazil.
Maternal age, social changes, and pregnancy outcome in Ribeir?o Preto, southeast Brazil, in 1978-79 and 1994
Goldani, Marcelo Zubaran;Bettiol, Heloisa;Barbieri, Marco Antonio;Tomkins, Andrew;
Cadernos de Saúde Pública , 2000, DOI: 10.1590/S0102-311X2000000400022
Abstract: this study focused on changes in demographic, social, and health-care patterns and pregnancy outcome related to maternal age from 1978-79 to 1994 in ribeir?o preto, s?o paulo state, brazil. information on pregnancy outcome was obtained from two cohorts of singleton live births, 6,681 births in 1978/79 and 2,839 births in 1994. a standardized questionnaire was submitted to mothers after delivery, and demographic information was collected from official records. there was a significant increase in teenage pregnancies (from 5.1% to 7.4%) and a decrease in infant mortality (36/1,000 to 17/1,000). there were significant decreases in the proportion of mothers with low schooling (24.5% to 14.4%), smoking (28.9% to 21.%), and multiparity (14.7% to 9.0%). prenatal coverage improved (from 23.4% to 9.0% of patients with fewer than 4 prenatal visits), while cesareans increased (from 30.6% to 50.8%), as did preterm delivery (7.2% to 13.6%) and low birthweight (7.2% to 10.6%). despite significant improvements in some maternal characteristics, the proportion of teenage pregnancies, preterm deliveries, low birthweight, and cesareans increased, raising concerns about the health costs and consequences for mothers and infants.
Avalia??o de um programa de suplementa??o alimentar
Gutierrez,Manoel Romeu; Bettiol,Heloisa; Barbieri,Marco Antonio;
Revista Panamericana de Salud Pública , 1998, DOI: 10.1590/S1020-49891998000700006
Abstract: the objective of this study was to evaluate the impact of a feeding supplementation program on the growth of undernourished children younger than 5 years in the city of guariba, state of s?o paulo, brazil. the sample consisted of 469 malnourished children enrolled in a feeding supplementation program sponsored by the state health secretariat. the children were divided into four groups according to how long they had been enrolled in the program: in group 1, the children had been enrolled for up to 12 months; in group 2, from 12 to 24 months; in group 3 from 24 to 36 months; and in group 4 the children had been enrolled for more than 35 months. percentiles for weight/age, height/age and weight/height were calculated for each child. to assess the impact of the program, reference curves for the anthropometric profile were constructed based on expected variations in population percentiles. the changes observed in each group were analyzed statistically (mcnemar). groups 1 and 2 presented weight recovery and gains in the weight/height ratios for the most severely malnourished children; in group 3, the weight/height ratio was maintained and there was a discrete tendency towards weight recovery, which was reversed in group 4, in which the weight was again low in relation to height. the feeding supplementation program temporarily minimized severe nutritional deficiencies but was not sufficient to recover and maintain normal growth.
@ Health: an excellence application in telemedicine
Bartolomeo Ficili,Paolo Borgotti,Marco Barbieri,Alberto De Russi
International Journal of Integrated Care , 2011,
Abstract:
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