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Search Results: 1 - 10 of 468786 matches for " Gustavo A; "
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Variation of Total Ozone during 24 August 2005 Magnetic Storm: A Case Study  [PDF]
Gustavo A. Mansilla
Atmospheric and Climate Sciences (ACS) , 2013, DOI: 10.4236/acs.2013.34049
Abstract:

This paper presents the longitudinal distribution of total ozone along several latitudinal circles from both hemispheres during a strong geomagnetic storm that occurred on 24 August 2005 after a solar proton event (the maximum flux of protons with energy > 10 MeV was 1.70 × 107 protons cm-2.day-1.sr-1 on 23 August). For that, we use average daily values of total ozone observations (=column ozone amount) in Dobson units for the period 18-25 August 2005 (obtained from the Total Ozone Mapping Spectrometer, TOMS). The considered storm occurred after a relatively quiet geomagnetic period and it is not superposed by another perturbation, which permit us to identify clearly the effects of the geomagnetic storm on total ozone. The results show statistically significant decreases in ozone along the latitudinal circles 70°N and 70°S (summer and winter), no statistically significant effects at middle latitudes (40°S) and sparse statistically significant increases at low latitudes (20°S). The role of some mechanisms to explain the features observed is considered.

Effect of Trisodium Citrate on the Properties of Electrodeposited Cu2ZnSnS4 (CZTS) Layers on ZnS Thin Films Using a 2-Electrode Method  [PDF]
Gustavo A. Silva Hernandez, Ajith R. Weerasinghe
Advances in Materials Physics and Chemistry (AMPC) , 2018, DOI: 10.4236/ampc.2018.88021
Abstract: Electrodeposition of CZTS thin films on ZnS was carried using a 2-electrode method to fabricate superstrate structure solar cells. A comprehensive study was performed on the effects of trisodium citrate on the CZTS electrolyte bath. In the present investigation, it is demonstrated that using a CZTS electrolyte with a concentration of 0.2 M trisodium citrate yields CZTS thin films with an electronic bandgap of 1.52 eV, a p-type nature, and good uniformity, which are all results desired for the fabrication of thin film solar cells. Characterization was performed using UV-Vi-IR optical absorption, SEM imaging, Raman spectrometry, and photoelectrochemical cells conducted for electronic bandgap, morphology, chemical composition, and semiconductor conductivity, respectively.
Alpha Centauri System and Meteorites Origin  [PDF]
Gustavo V. López, Juan A. Nieto
Journal of Applied Mathematics and Physics (JAMP) , 2018, DOI: 10.4236/jamp.2018.611199
Abstract: We propose a mathematical model for determining the probability of meteorite origin, impacting the earth. Our method is based on axioms similar to both the complex networks and emergent gravity. As a consequence, we are able to derive a link between complex networks and Newton’s gravity law, and as a possible application of our model we discuss several aspects of the Bacubirito meteorite. In particular, we analyze the possibility that the origin of this meteorite may be alpha Centauri system. Moreover, we find that in order for the Bacubirito meteorite to come from alpha Cen and be injected into our Solar System, its velocity must be reduced one order of magnitude of its ejected scape velocity from alpha Cen. There are several ways how this could happened, for example through collision with the Oort cloud objects (located outside the boundary of our Solar System), and/or through collisions within the Solar meteorites belt (located between Mars and Jupiter). We also argue that it may be interesting to study the Bacubirito meteorite from the perspective of the recently discovered Oumuamua object.
Uso de teorías y modelos en contribuciones de la Revista de Salud Pública de la Universidad Nacional de Colombia, 1999-2004
Cabrera A,Gustavo A;
Revista Facultad Nacional de Salud Pública , 2008,
Abstract: objective: to identify the main features of the theories and theoretical models used in the articles published by the revista de salud pública (public health journal) of the national university of colombia. methods: in february 2005 all the numbers published by the journal from 1999 to 2004 were analyzed. a trained reader registered different variables of interest based on instruments and criteria adapted from previous studies. results: a total amount of six volumes corresponding to 21 numbers of the journal were read, 18 of the periodical publication and 3 special numbers. a total amount of 154 contributions were classified into 66 articles or research summaries (43%), 62 essays, revisions or conferences on specific topics (40%), and 26 on up-to-date subjects or symposia (17%). the main topics were health system and policies (26%), epidemiology (21%) and health management (13%). although 34 of 154 articles (22%) referred to 9 theories and 39 models as theoretical frameworks, only 17 (11%) involve a deep usage of them according to the criteria adopted. conclusions: the articles published in the journal revealed a limited use of theories and models and a lack of rigor in the way the authors structured them from the point of view of subject, methodology and analysis.
Theories and models used on articles published by the Public Health Journal of the National University of Colombia, 1999-2004
Gustavo A. Cabrera A
Revista Facultad Nacional de Salud Pública , 2008,
Abstract: Objective: to identify the main features of the theories and theoretical models used in the articles published by the Revista de Salud Pública (Public Health Journal) of the National University of Colombia. Methods: in February 2005 all the numbers published by the journal from 1999 to 2004 were analyzed. A trained reader registered different variables of interest based on instruments and criteria adapted from previous studies. Results: A total amount of six volumes corresponding to 21 numbers of the journal were read, 18 of the periodical publication and 3 special numbers. A total amount of 154 contributions were classified into 66 articles or research summaries (43%), 62 essays, revisions or conferences on specific topics (40%), and 26 on up-to-date subjects or symposia (17%). The main topics were health system and policies (26%), epidemiology (21%) and health management (13%). Although 34 of 154 articles (22%) referred to 9 theories and 39 models as theoretical frameworks, only 17 (11%) involve a deep usage of them according to the criteria adopted. Conclusions: the articles published in the journal revealed a limited use of theories and models and a lack of rigor in the way the authors structured them from the point of view of subject, methodology and analysis.
La pesquería mixta de las centollas Lithodes santolla y Paralomis granulosa (Anomura: Lithodidae) en Tierra del Fuego, Argentina
Lovrich,Gustavo A.;
Investigaciones marinas , 1997, DOI: 10.4067/S0717-71781997002500004
Abstract: in the beagle channel, argentina (55os; 66ow) the individuals of two sympatric species of lithodids occur simultaneously in commercial traps: the southern king crab, lithodes santolla and the false southern king crab, paralomis granulosa. hence, this is a mixed fishery. both species differ markedly in their reproductive potential and therefore, if overexploited, time for stock rebuilding also differs between the species. l. santolla is large (maximum size of 180 mm carapace length, cl, and 6 kg weight), has a generation time of 6 y, the reproductive cycle is annual and females carry between 5,000-32,000 eggs per female per clutch. p. granulosa is smaller than its cogener (maximum 115 mm cl and 1.5 kg weight), has a generation time of 12 y, the reproductive cycle is biennial and females carry between 800-10,000 eggs per female per clutch. in the beagle channel near the city of ushuaia, l. santolla population was over-exploited, mainly due to the extraction of larger animals, irrespective of the sex. in the period 1975-1994, the deacrese of: the yield per trap, the average mean size of trapped individuals, the frequency of ovigerous females, and the constant sex-ratio, evidenced the extraction of all marketable animals from the population. therefore, in 1994, the fishing for l. santolla was closed to allow the population to recover to acceptable commercial and biological levels. for p. granulosa, it is suggested that its life-history traits constrains fishing to low rates, since its recuperation potential is lower than that of l. santolla
A new species of Chaetostoma Tschudi (Siluriformes: Loricariidae) from Colombia with a definition of the C. anale species group
Ballen, Gustavo A.;
Papéis Avulsos de Zoologia (S?o Paulo) , 2011, DOI: 10.1590/S0031-10492011002600001
Abstract: chaetostoma formosae sp. nov. is described from piedmont tributaries of the upper río meta on the cordillera oriental in colombia. the new species is distinguished from its congeners by the presence of an elongate unbranched anal-fin ray with two posterior dermal ridges in mature males, the presence of strongly recurved cheek odontodes, the presence of a parieto-supraoccipital dermal keel, the posterior margin of the pelvic-fin strongly projected and angulate in shape in mature males, and by details of coloration. the new species belongs to an informal monophyletic group herein called the chaetostoma anale species group, along with two additional species, c. anale and c. jegui, from colombia and brazil respectively, based on an apomorphic modification of the anal fin in mature males.
Da doen?a renal ao renal cr?nico
Matta, Gustavo Corrêa;
Physis: Revista de Saúde Coletiva , 2000, DOI: 10.1590/S0103-73312000000100004
Abstract: this paper describes the complex network of beliefs and values that envelopes the practices, discourses, habits, routines and language of individuals suffering from chronic renal failure and undergoing hemodialysis. taking a neopragmatic perspective of the individual as a starting point, the institutional trajectory of the chronic patient was investigated, charting his/her path, the descriptions of the disease, his/her body and identity; his/her relationship with medical discursive practices, state intervention and his/her new social identity: that of a chronic renal.
Economic ideas in the early Republic of Bolivia: notes on an anonymous manuscript of 1830
Robles,Gustavo A. Prado;
Revista de Humanidades y Ciencias Sociales (Santa Cruz de la Sierra) , 2005,
Abstract: this essay examines the theoretical framework underlying an anonymous manuscript of 1830 which contains a discussion of bolivian economic problems during the early years of the republic, and a proposal for protectionism. the manuscript is an example of the degree of refinement that had been achieved by the intellectual elite of charcas towards the end of the colonial period. in this essay we question the hypothesis of doctrinal unity between protectionists and free-traders during the first decades of the republic: it is shown that the anonymous author is critical and selective vis-a-vis the principles of classical political economy, and that his protectionist prescriptions are based, for the most part, on the notion of historical relativism as expounded in montesquieu?s the spirit of laws. we begin with a brief presentation of the contents of the manuscript, followed by an analysis of the author?s theoretical framework, and concluding with a review of the set of protectionist measures adopted by the bolivian government between 1829 and 1832.
A organiza??o mundial da saúde: do controle de epidemias à luta pela hegemonia
Matta, Gustavo Corrêa;
Trabalho, Educa??o e Saúde , 2005, DOI: 10.1590/S1981-77462005000200007
Abstract: the objective of this article is to discuss the emergence of the world health organization (who) as an international specialized agency. it also debates how the organization operates, major historic and political landmarks and its strategies in the struggle for hegemony in the international sanitary scenario. for such, we researched who's documents, directors-general's speeches, texts introducing the institution, articles and editorials. two specific moments were of fundamental influence to who's international health policies: the program health for all (2000) and the policies fostered by the gro-brundtland administration (1998-2002). in this period, not only profound transformations in international health policies were undertaken, but also, the need to establish political and methodological links to the globalization of the economy and the global health policies emerged.
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