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Search Results: 1 - 10 of 32025 matches for " Marcelo;Costa "
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Clinical Psychophysical Assessment of the ON- and OFF-Systems of the Magnocellular and Parvocellular Visual Pathways  [PDF]
Marcelo Fernandes Costa
Neuroscience & Medicine (NM) , 2011, DOI: 10.4236/nm.2011.24043
Abstract: We developed a psychophysical paradigm for the clinical assessment of the contrast sensitivity (CS) mediated by the ON- and OFF-systems of the Magnocellular and Parvocellular pathways. We designed a stimulus considering two dimensions: two spatial frequencies (0.5 and 4.5 cpd) and two temporal rates of flicker (33 ms and 1500 ms). To evidence the ON- and OFF responses, the CS was measured for two polarities of light with luminance changes of 0.6 dB steps above and below the medium luminance grey background. We tested 38 healthy volunteers. The results shows that Magnocellular contrast sensitivity was higher than Parvocellular for the 33 ms flickering stimulus and the Parvocellular contrast sensitivity was higher than Magnocellular for 1500 ms stimuli. The reliability of the test was checked and confirmed. We concluded that the test performs a rapid measurement of the CS mediated by the ON and OFF systems of Magnocellular and Parvocellular pathways. It is useful in clinical protocols due to its high sensitivity and good reliability.
Visual acuity evaluation in children with hydrocephalus: An electrophysiological study with sweep visual evoked potential  [PDF]
Silvana Alves Pereira, Marcelo Fernandes Costa
World Journal of Neuroscience (WJNS) , 2012, DOI: 10.4236/wjns.2012.21006
Abstract: The objective was to measure the visual acuity (VA) of children with the diagnosis of hydrocephalus with or without peritoneal-ventricular shunt (PVS). A total of 55 children were included in the study (34 Female), with an age range of 0 to 291 weeks. The VA was measured by the sweep visual evoked potential technique. Of those with a PVS, in 31 the ventricular valve was inserted before 15 days after the diagnosis whereas in 14 the ventricular valve was inserted after 15 days. The sweep VEP was performed in all children, 95 exams (94%) were abnormal and only 6 were normal. There was a statistical difference in the VA between children with a PVS inserted before 15 days of the diagnosis and children with a PVS after 15 days (p = 0.038) or those without a shunt (p = 0.031). Children with no complications of the PVS had a better VA as compared to those with shunt complications (p < 0.001). In the group of children with complications, again those who had a shunt inserted be-fore 15 days had better VA results in com- parison to those in whom the shunt was inserted after 15 days (p = 0.029). No statistical difference in the VA was found between children without the PVS and with those in which the shunt was inserted after 15 days of the di-agnosis of hydrocephalus (p = 0.699). We conclude that the delayed insertion of the PVS may compromise the visual development of these children.
A Novel Approach for Inferring the Proportion of Terrestrial Organic Matter Input to Marine Sediments on the Basis of TOC:TN and δ13Corg Signatures  [PDF]
Antonio Fernando Menezes Freire, Marcelo Costa Monteiro
Open Journal of Marine Science (OJMS) , 2013, DOI: 10.4236/ojms.2013.32009

The ratio of total organic carbon to total nitrogen (TOC:TN) and the stable carbon isotope ratio of organic matter (δ13Corg) are widely applied for inferring the origin of organic matter (OM) in Quaternary marine sediments. A plot of TOC:TN vs. δ13Corg is useful for such studies but is strongly based on qualitative constraints. This study is based on the qualitative characterization of the source of Quaternary OM via analysis of TOC:TN and δ13Corg signatures, but also proposes a probability parameter, which combines both signatures, to infer the amount of Terrestrial OM Input (TOMI). This index provides a method for quantifying the proportion of terrestrial OM vs. marine OMin a more comprehensive manner. The TOMI index concept was applied to a study area in theJoetsuBasin, eastern margin of theJapanSea, where previous studies have characterized theOMfrom the Last Glacial Maximum (LGM) to the present. The upwards increase in TOC indicates thatOMproduction during the Holocene was higher than during the LGM. The enriched δ13Corg signature upwards and decrease in TOC:TN suggest predominantly marine phytoplankton OM during the Holocene. Throughout the LGM, low OM production with depleted δ13C

Biology, diversity and strategies for the monitoring and control of triatomines - Chagas disease vectors
Costa, Jane;Lorenzo, Marcelo;
Memórias do Instituto Oswaldo Cruz , 2009, DOI: 10.1590/S0074-02762009000900008
Abstract: despite the relevant achievements in the control of the main chagas disease vectors triatoma infestans and rhodnius prolixus, several factors still promote the risk of infection. the disease is a real threat to the poor rural regions of several countries in latin america. the current situation in brazil requires renewed attention due to its high diversity of triatomine species and to the rapid and drastic environmental changes that are occurring. using the biology, behaviour and diversity of triatomines as a basis for new strategies for monitoring and controlling the vectorial transmission are discussed here. the importance of ongoing long-term monitoring activities for house infestations by t. infestans, triatoma brasiliensis, panstrongylus megistus, triatoma rubrovaria and r. prolixus is also stressed, as well as understanding the invasion by sylvatic species. moreover, the insecticide resistance is analysed. strong efforts to sustain and improve surveillance procedures are crucial, especially when the vectorial transmission is considered interrupted in many endemic areas.
Consumo cultural e espa?os sociais: os vestibulandos das universidades públicas na cidade do Rio de Janeiro, 1990
Ferreira, Marcelo Costa;
Opini?o Pública , 2003, DOI: 10.1590/S0104-62762003000100007
Abstract: the purpose of this article is to inquiry about cultural capital and life style(s) associations among university applicants to the public universities of rio de janeiro at 1990. the puzzle is which social spaces and cultural consumer practices should be found among these prospective students? the data analysis is based on the social and cultural questionnaire research applied to all the applicant students of the year 1990 (year of) in the following institutions: the federal university of rio de janeiro (ufrj), the federal rural university of rio de janeiro (ufrrj), the federal fluminense university (uff), the state university of rio de janeiro (uerj) and the national school of statistical sciences, of brazilian institute of geography and statistics (ence/ibge). in short, two major findings are detached. the first one is that correspondence analysis plots of literary consumer consumption, cultural practices and inequalities attributes are summarized in three major clusters. the first is applicants with strong cultural capital, however without the same level of economic resources. the second is students with low access to cultural goods, and the third and middle segment has an average among the two others segments. the second finding is the high level of inequality to cultural resources access, even to the prospective students who are able to apply to a university.
Participa??o e comportamento político no Estado de S?o Paulo, 1990
Ferreira, Marcelo Costa;
Opini?o Pública , 2000, DOI: 10.1590/S0104-62762000000200004
Abstract: the purpose of this article is to analyze the relationship between political participation and electoral behavior. empirical evidence comes from a survey conducted in s?o paulo by the ibope in 1990. the main finding suggests that voting and left-wing trends are correlated. however, this finding does not exclude an association between rightist voting and political participation. in short, few modalities of participation are related to electoral behavior, and political apathy should be correlated with few credibility in politics as mechanism of representation and conflict management.
Movimentos oculares no bebê: o que eles nos indicam sobre o status oftalmológico e neurológico
Costa, Marcelo Fernandes;
Psicologia USP , 2007, DOI: 10.1590/S0103-65642007000200004
Abstract: abnormal eye movements may be a result of early abnormal development or a sign of underlying neurological or neuromuscular disease. however, it is important to the clinician to know such abnormalities and to distinguish them from normal but immature eye movements. this paper intends to shed some light on the different types of ocular movements, on how to interpret them in healthy infants and what alterations are found in different visual and neurological diseases.
A clínica da psicofísica
Costa, Marcelo Fernandes;
Psicologia USP , 2011, DOI: 10.1590/S0103-65642011005000008
Abstract: introducing the psychophysics as an applied science in investigating and approaches and clinical diagnostics. initially, we introduce something of the epistemological and theoretical aspects of the area, we move to approaches that may provide on psychophysics clinical applicability and finally, we discuss the recent advances in clinical application, we present the experiences of our laboratory for clinical research in psychophysics, ending with the prospects for extending the use of psychophysics to clinical investigations of perceptual functions more complex.
Associativismo e contato político nas regi?es metropolitanas do Brasil: 1988-1996. Revisitando o problema da participa??o
Ferreira, Marcelo Costa;
Revista Brasileira de Ciências Sociais , 1999, DOI: 10.1590/S0102-69091999000300006
Abstract: the article compares the percentage of political participation (affiliation to unions, employees' associations, neighbourhood associations, sporting/cultural associations, philanthropic/religious associations; requests, demands, suggestions and complaints made to politicians; affiliation and militancy in political parties) in six metropolitan areas of brazil (s?o paulo, rio de janeiro, salvador, recife, porto alegre and belo horizonte) in the years 1988 and 1996. the comparison was made using a sub-sample from the 1988 national household sample survey (pesquisa nacional de amostra por domicílio - pnad), and the monthly employment survey (pme) of april 1996, which is compatible, and analysing information in the supplements on political participation contained in these two surveys. in the analysis of these data, a paradox is found: notwithstanding the institutional and political changes which have taken place in the country during the last eight years, the number of brazilians actually participating in associations, both in 1988 and 1996, is tiny, and this contradicts what is found in the literature which emphasizes the significant growth in the number of associations during the 70's and 80's.
Permeavel, ma non troppo?: A mobilidade social em setores de elite, Brasil - 1996
Ferreira, Marcelo Costa;
Revista Brasileira de Ciências Sociais , 2001, DOI: 10.1590/S0102-69092001000300009
Abstract: the objective of this article is to analyze the brazilian elites based on socioeconomic variables that affect the intergeneration occupational mobility between members and former-members of this social stratum. the methodological procedures used here consist of investigating the relationship between ascending, stable and descending intergeneration occupational mobility and other variables as skin color, occupation in the public or private sector, number of jobs, schooling and age insertion in the labor market. the empirical source is the social mobility supplement presented in the "1996 national survey by residential sample" (pnad) carried out by ibge. the main conclusion of this study is based on the evidences that the brazilian elites present an ambivalent profile in their social composition: on one hand, social inertia was found in 15% of the members of this stratum and, on the other hand, 85% of the ascending members could easily fall, since they possess the same social characteristics of the ones that have once been excluded from the elite.
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