Papers by Francisco A . B . Coutinho
Pnór,oGo tste tra.bal.ho de tese foi reallzado com o objetivo de preencher n¡.::te dos recÍuísl.t... more Pnór,oGo tste tra.bal.ho de tese foi reallzado com o objetivo de preencher n¡.::te dos recÍuísl.tos exlql<1os peJ'o Dep'de Ftsica cla Faculdade de Fi-losofi-a Ciênelas e Letras da Universidade de são Faulo, para a. ok,tenção do grau cle rnMestre em c1êncÍasr'. Pocl.e parecer estrantio portanto c¡ue não se trate d'e Flsíca prg prlamente c1it,a e muito menos da Flsica de frontelra sujeita ã competi.ção ínternacfonal-r como são a maior parte clas tesee a- apreseniacJ,as a êste Departanento. Entretanto, aeredltanos que possa ser conii.clerado f¡lslea iApllcada e assLm satlsfatõrlo pg ra os fi.ns aos guai-s s@ destfna Para quo so tornasse uma. leltura mafs aqradavel o trahalho fol dtvfdJ.óo em t,rêe partes. A primef ra p¡ttC trata dos aepectos matêmñtåcoa Eue Ecrão ueadoa nao duae r€ßtanteE e exemploa de sua aplfeação Ë, fenõmg,gçrçJfsfeoa. lrÏa sequniîa parte.. á apresentacLa a expllcação cle um fenômeno ecoloqlco que o"ottã eÀ poputações de PlanorbLdeos os quafs serão apresen- ; tados nä momento oportuno e suas relações com o l{omem serãc> saLlenta|"". Finalmente a terceira parte trata do mecanismo cle controle crue permite as populações c1e Planorbídfos alcançar o eq¡nri'drliÌ:rio i+stacíeitrårio " . A terceíra parte é urn caso pa-r.ticular do aspecto rnaÍs interessante cfue Cts fenomenos bíológÍcos podem ter para FÍsl-cos" F.ealmente, cfualguer ser viv6 .ou aqrupamento de sêres, pode ser cons j-<lerado, sob alqum pon.to de. vista como uma máqu! na. Gue receÌ:¡e d.o exterior eertas mensaçtens e ajusta seu compcr tamento de acôrc1e' com estas " .ú a t* i. )"1 À natureza das mênsagens e o mecanlsmo da resposta d,ependem mul-tas vezes de fenômenos flsicos slmples. o estudo dêstes, além d.e ser útll flara o entendÍmento dos fenômenos da vida, pode eonter resul- tados lnteressantes do ponto de vl-sta prátieo. Agradecimentos ¡\ À.B.Coutlnho a cruem devo ml-nha formação cLentlfica báslca, ,,.¿ proposição do problema crue é tratado nêste tralralho e metade dos meus qenes.
Brazilian Journal of Physics, Jun 3, 2016
A theorem of Hegerfeldt [GCH98] establishes, for a class of quantum systems, a dichotomy between ... more A theorem of Hegerfeldt [GCH98] establishes, for a class of quantum systems, a dichotomy between those which are permanently localized in a bounded region of space, and those exhibiting instantaneous spreading. We analyse in some detail the physical inconsistencies which follow from both of these options, and formulate which, in our view, are the basic open problems.
Revista brasileira de fisica, 1981
Journal of Liver, Aug 3, 2015
This paper studies the effects in low energy nuclear physics of a possible time reversal invarian... more This paper studies the effects in low energy nuclear physics of a possible time reversal invariance (TRI) violation in the electromagnetic interaction. It is shown that this effect appears as a two body short range TRI violating transition operator or as a two and three body TRI violating potential. Two cases are studied. Firstly a TRI violating NNgamma vertex is
Journal of Mathematical Physics, Sep 1, 1985
Physics Letters, Feb 1, 1984
Abstract We provide simple sufficient conditions for the existence of a bound state in a system o... more Abstract We provide simple sufficient conditions for the existence of a bound state in a system of N particles interacting via a purely attractive two-body potential. Our method is based on a variational approach.
BackgroundAt the moment we have more than 109 million cases and 2.4 million deaths around the wor... more BackgroundAt the moment we have more than 109 million cases and 2.4 million deaths around the world and vaccination represents the only hope to control the pandemic. Imperfections in planning vaccine acquisition and difficulties in implementing distribution among the population, however, have hampered the control of the virus so far.MethodsWe propose a new mathematical model to estimate the impact of vaccination delay against COVID-19 on the number of cases and deaths by the disease in Brazil. We apply the model to Brazil as a whole and to the State of Sao Paulo, the most affected by COVID-19 in Brazil. We simulated the model for the populations of the State of Sao Paulo and Brazil as a whole, varying the scenarios related to vaccine efficacy and compliance from the populations.ResultsThe model projects that, in the absence of vaccination, almost 170 thousand deaths and more than 350 thousand deaths until the end of 2021 for Sao Paulo and Brazil, respectively. If in contrast, Sao Pa...
Revista Brasileira de Ensino de Física, 2020
Most books on Thermodynamics explain what thermodynamic potentials are and how conveniently they ... more Most books on Thermodynamics explain what thermodynamic potentials are and how conveniently they describe the properties of physical systems. Certain books add that, to be useful, the thermodynamic potentials must be expressed in their "natural variables". Here we show that, given a set of physical variables, an appropriate thermodynamic potential can always be defined, which contains all the thermodynamic information about the system. We adopt various perspectives to discuss this point, which to the best of our knowledge has not been clearly presented in the literature.
Revista Brasileira de Ensino de Física, 2020
The continuous spectrum of a quantum mechanical (QM) system contains important information on the... more The continuous spectrum of a quantum mechanical (QM) system contains important information on the system. However, the normalization of wave functions of the continuous spectrum is often difficult and therefore is often omitted from the books on QM. We discuss this problem and show how we can overcome this problem technically, with some examples.
Research Square (Research Square), Jun 15, 2021
At the moment we have more than 109 million cases and 2.4 million deaths around the world and vac... more At the moment we have more than 109 million cases and 2.4 million deaths around the world and vaccination represents the only hope to control the pandemic. Imperfections in planning vaccine acquisition and difficulties in implementing distribution among the population, however, have hampered the control of the virus so far. We propose a new mathematical model to estimate the impact of vaccination delay against the 2019 coronavirus induces disease (COVID-19) on the number of cases and deaths by the disease in Brazil. We apply the model to Brazil as a whole and to the State of Sao Paulo, the most affected by COVID-19 in Brazil. We simulated the model for the populations of the State of Sao Paulo and Brazil as a whole, varying the scenarios related to vaccine efficacy and compliance from the populations. The model projects that, in the absence of vaccination, almost 170 thousand deaths and more than 350 thousand deaths until the end of 2021 for Sao Paulo and Brazil, respectively. If in contrast, Sao Paulo and Brazil had enough vaccine supply and so started a vaccination campaign in January with the maximum vaccination rate, compliance and efficacy, they could have averted more than 112 thousand deaths and 127 thousand deaths, respectively. In addition, that for each month of delay the number of deaths increases monotonically in a logarithm fashion, for both the State of Sao Paulo and Brazil as a whole. Our model shows that the current delay in the vaccination schedules that is observed in many countries has serious consequences in terms of mortality by the disease and should serve as an alert to health authorities to speed the process up such that the highest number of people to be immunized is reached in the shortest period of time.
Epidemiology and Infection, 2018
Vaccinating monkeys against yellow fever (YF) has been a common practice in the beginning of the ... more Vaccinating monkeys against yellow fever (YF) has been a common practice in the beginning of the 17D vaccine development. Although it may seem strange at first sight, vaccinating monkeys as a public health strategy is, we think, feasible and theoretically could eliminate the infection among non-human primates, interrupting the virus circulation (or significantly reducing it) and therefore reducing the risk of spilling over to the human population. We propose a series of studies that could demonstrate (or not) the efficacy and feasibility of vaccinating non-human primates YF reservoirs living in green areas of urban centres to cut off or curb the virus circulation that recurrently spill over to the human population. Therefore, vaccinating monkeys in relatively small green areas of the urban centres is perhaps the ultimate solution for the Brazilian recurrent YF epizootics.
Tropical Medicine & International Health, 2015
This work is an attempt to estimate the risk of infections importation and exportation by travele... more This work is an attempt to estimate the risk of infections importation and exportation by travelers. In it we propose a model that takes into account the force of infection of the disease in the endemic country, which can either be a visited country (source of infection importation) or a country from where local residents export the infection when travel in the latent condition for disease-free countries. The model is deterministic but a preliminary stochastic formulation is presented in the appendix. It considers two countries: one is the host home-country and the other is the source country (with an endemic infectious disease). Susceptible individuals travel from their home-country to the endemic country and eventually return infected. The input of the model is the force of infection at the visited/source country which is assumed to be known and we assume that, in the case of disease importation, travelers are subject to the same risk of infection as local residents but do not con...
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Papers by Francisco A . B . Coutinho