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Search Results: 1 - 10 of 616941 matches for " Franklin J. Méndez "
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Biological Template Based on ent-Kaurane Diterpenoid Glycosides for the Synthesis of Inorganic Porous Materials  [PDF]
ángela B. Sifontes, Mirla Rodriguez, David Freire, Wendy Rondón, Ligia Llovera, Edgar Ca?izales, Franklin J. Méndez, Andrea Monaco, Yraida Díaz
Advances in Chemical Engineering and Science (ACES) , 2013, DOI: 10.4236/aces.2013.34035
Abstract: Recent studies on the preparation of porous nano-materials revealed that the use of kaurane diterpenoids molecules from steviol as biological template favors the obtaining of metallic oxides with tubular morphology as nanorods or nanofibers. In this sense, the present contribution shows an analysis in order to understand how these glycosides of kaurane diterpenoids control the nucleation and growth of inorganic materials favoring the obtaining of these morphologies. For this purpose, it was necessary to carry out studies of the leaf aqueous extract of Stevia rebaudiana by HRTEM, FTIR and 1H-NMR.
Second order parameter-uniform convergence for a finite difference method for a singularly perturbed linear parabolic system
V. Franklin,M. Paramasivam,S. Valarmathi,J. J. H. Miller
Mathematics , 2010,
Abstract: A singularly perturbed linear system of second order partial differential equations of parabolic reaction-diffusion type with given initial and boundary conditions is considered. The leading term of each equation is multiplied by a small positive parameter. These singular perturbation parameters are assumed to be distinct. The components of the solution exhibit overlapping layers. Shishkin piecewise-uniform meshes are introduced, which are used in conjunction with a classical finite difference discretisation, to construct a numerical method for solving this problem. It is proved that the numerical approximations obtained with this method are first order convergent in time and essentially second order convergent in the space variable uniformly with respect to all of the parameters.
Using Program Visualization to Improve ICT skills towards achieving Vision 2030
Mutua M. Stephen,Wabwoba Franklin,Ogao J. Patrick,Abenga Elizabeth
International Journal of Information and Communication Technology Research , 2011,
Abstract: ICT has become an imperative component in enhancing industrialization and socio-economic growth in developed and developing countries. It is thus irresistible for any nation that wishes and plans to expand its growth. In the Vision 2030, the country seeks to provide ICT services that are quality and affordable to many. Any ICT component will include some software (program) and hardware. However, programming remains a hurdle to many ICT professionals, teachers and the students thereof and thus country imports most of its software. This poses a danger of slowing down possible innovations and developments that would otherwise be realized if the programming skill is mastered. This paper evaluates programming from the students’ perspective on its relevance, understandability and usage of emerging trends to learn it. During the study, a sampled population of students of IT and computer science students was evaluated using questionnaires. It was evident that most students desired better ways other than the chalk-board method or using PowerPoint slides. It however emerged that most students were unaware of existing tools that can aid learn programming. The paper culminates by a brief discussion of the emerging trend of using program visualization tools to teach/learn programming.
Investigation of CO, C2H6 and aerosols in a boreal fire plume over eastern Canada during BORTAS 2011 using ground- and satellite-based observations, and model simulations
D. Griffin,K. A. Walker,J. E. Franklin,M. Parrington
Atmospheric Chemistry and Physics Discussions , 2013, DOI: 10.5194/acpd-13-11071-2013
Abstract: We present the results of total column measurements of CO, C2H6 and fine mode aerosol optical depth (AOD) during the "Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites" (BORTAS-B) campaign over Eastern Canada. Ground-based observations, using Fourier transform spectrometers (FTSs) and sun photometers, were carried out in July and August 2011. These measurements were taken in Halifax, Nova Scotia, which is an ideal location to monitor the outflow of boreal fires from North America, and also in Toronto, Ontario. Measurements of fine mode AOD enhancements were highly correlated with enhancements in coincident trace gas (CO and C2H6) observations between 19 and 21 July 2011, which is typical for a smoke plume event. In this paper, we focus on the identification of the origin and the transport of this smoke plume. We use back-trajectories calculated by the Canadian Meteorological Centre as well as FLEXPART forward-trajectories to demonstrate that the enhanced CO, C2H6 and fine mode AOD seen near Halifax and Toronto originated from forest fires in Northwestern Ontario that occurred between 17 and 19 July 2011. In addition, total column measurements of CO from the satellite-borne Infrared Atmospheric Sounding Interferometer (IASI) have been used to trace the smoke plume and to confirm the origin of the CO enhancement. Furthermore, the emission ratio (ERC2H6/CO) and the emission factor (EFC2H6) of C2H6 (with respect to the CO emission) were estimated from these ground-based observations. These C2H6 emission results from boreal fires in Northwestern Ontario agree well with C2H6 emission measurements from other boreal regions, and are relatively high compared to fires from other geographical regions. The ground-based CO and C2H6 observations were compared with outputs from the 3-D global chemical transport model GEOS-Chem, using the Fire Locating And Monitoring of Burning Emissions (FLAMBE) inventory. Agreement within the stated measurement uncertainty was found for the magnitude of the enhancement of the total columns of CO (~3%) and C2H6 (~8%) between the measured and modelled results. However, there is a small shift in time (of approximately 6 h) of arrival of the plume over Halifax between the results.
Estudos histomorfométrico e histológico das les?es ósseas causadas por flúor em aves
Raffi, Margarida Buss;Méndez, Maria del Carmen;Riet-Correa, Franklin;
Pesquisa Veterinária Brasileira , 1997, DOI: 10.1590/S0100-736X1997000200005
Abstract: sodium fluoride was administered in the water to 2 groups of 25 shaver female poultry. group a received fluoride from 1 to 120 days of age and group b from 61 to 120 days. each group was divided into 5 treatments, with 5 chickens each, which received 0, 25, 50, 200, and 400 ppm of fluoride in the water, respectively. all animals were killed at 120 days of age. for histomorphometric studies the left femur and tibia were used, and for histologic studies the right femur and tibia. in the cortical bone, cortical porosity was slightly increased by fluoride, but the differences with the control group were not significant. cortical thickness increased in the animals treated with fluoride (p<0,05, r2 = 0,59 ). in the trabecular bone, of group a, trabecular thickness (tt) (p<0,05, r2 = 0,63) and trabecular bone volume (tbv) (p<0,05, r2 = 0,72) increased in treatments receiving 25-200 ppm, and decreased in the 400 ppm treatment, as it was demonstrated by quadratic regression analysis. in group b there was a positive linear correlation on tt (p<0,05, r2 = 0,98) and tbv (p<0,05, r2 = 0,77) with fluoride ingestion.the osteoid surface was also positively correlated with the amount of fluoride ingested by the animals (p<0,001, r2 = 0,80). these results suggest that fluoride improves osteoblastic function resulting in increased osteoid production and bone apposition. in the other hand, in the animals treated with 400 ppm of fluoride for 120 days bone apposition was reduced suggesting a functional alteration of the osteoblasts or improved bone resorption. in the histological study of bone tissue all animals that received fluoride showed an increased trabecular thickness which was more marked in the 200-400 ppm treatments. in chickens treated with 200-400 ppm of fluoride osteoblasts and osteoclasts were more numerous suggesting an increased bone turnover. in cortical bone haversian canals were narrowed on the periosteal surfaces and resorption spaces were enlarged on the endosteal su
Estudos histomorfométrico e histológico das les es ósseas causadas por flúor em aves
Raffi Margarida Buss,Méndez Maria del Carmen,Riet-Correa Franklin
Pesquisa Veterinária Brasileira , 1997,
Abstract: Fluoreto de sódio foi administrado na água de 2 grupos de 25 aves, fêmeas, da ra a Shaver. O grupo A recebeu flúor do 1 ao 120 dia de idade e o grupo B do 61 ao 120 dia de idade. Cada grupo foi dividido em 5 níveis de tratamento: 0, 25, 50, 200 e 400 ppm de flúor, com 5 animais por tratamento. Todos os animais foram sacrificados aos 120 dias de idade. Para o estudo histomorfométrico foram coletados o fêmur e a tíbia esquerdos, e para o estudo histológico foram coletados fêmur e tíbia direitos. No estudo histomorfométrico do osso compacto observou-se um discreto aumento da porosidade cortical, que n o foi estatisticamente significativo. A espessura do osso cortical aumentou nos animais tratados com flúor (p<0,05, r2 = 0,59). No osso trabecular, do grupo A, houve um aumento da espessura trabecular (ET) (p<0,05, r2 = 0,63) e do volume trabecular ósseo (VTO) (p<0,05, r2 = 0,72) até a dose de 200 ppm; e, na dose de 400 ppm, ocorreu um decréscimo, demonstrado pela regress o quadrática obtida na análise de regress o. No grupo B houve um aumento progressivo da ET (p<0,05, r2 = 0,98) e do VTO (p<0,05, r2 = 0,77) diretamente relacionado com a dose de flúor. A superfície de osteóide (SO) apresentou, também, um aumento gradativo relacionado com a dose, nos animais tratados com flúor (p<0,001, r2 = 0,80). Esses resultados sugerem que o flúor estimula a fun o osteoblástica, resultando em aumento da SO, e consequentemente maior aposi o óssea. No entanto, nos animais tratados com 400 ppm, durante 120 dias, esse estímulo sobre a aposi o óssea n o foi t o evidente, sugerindo que o flúor determina alguma altera o funcional sobre os osteoblastos ou um aumento da reabsor o óssea. Histologicamente, observou-se espessamento trabecular nos animais tratados com flúor, mais marcado nas doses de 200 e 400 ppm, em ambos os grupos. Sobre a superfície trabecular, dos animais tratados com 200 e 400 ppm, evidenciou-se, principalmente, osteoblastos ativos e osteoclastos, sugerindo um aumento da remodela o óssea. No osso cortical observou-se diminui o dos canais de Havers, próximos a superfície periosteal, e aumento das lacunas de reabsor o próximas a superfície endosteal.
Experimental intoxication by the leaves of Melia azedarach (Meliaceae) in cattle
Carmen Méndez Maria del,Arag?o Marcos,Fabiana Elias,Riet-Correa Franklin
Pesquisa Veterinária Brasileira , 2002,
Abstract: Green leaves of Melia azedarach were administered at single doses ranging from 5 to 30 g/kg bw to 11 calves. Clinical signs were depression, ruminal stasis, dry feces with blood, ataxia, muscle tremors, sternal recumbency, hypothermia and abdominal pain. Serum AST and CPK were increased. Signs appeared from 8 to 24 hours after dosing, and the clinical course lasted from 2 to 72 hours. Three calves dosed with 30g/kg bw died. The macroscopic findings included intestinal congestion, yellow discoloration of the liver, brain congestion and dry feces with blood in the rectum. The liver showed swollen and vacuolated hepatocytes. Necrotic hepatocytes were scattered throughout the parenchyma or concentrated in the periacinar zone. Degenerative and necrotic changes were observed in the epithelium of the forestomachs. There was also necrosis of the lymphoid tissue. Skeletal muscles showed hyaline degeneration and fiber necrosis. The necrotic fragments contained floccular or granular debris with infiltration by macrophages and satellite cells.
Intoxica o experimental com frutos de Melia azedarach (Meliaceae) em suínos
Méndez Maria del Carmen,Elias Fabiana,Riet-Correa Franklin,Gimeno Eduardo Juan
Pesquisa Veterinária Brasileira , 2006,
Abstract: Frutos maduros, triturados, de Melia azedarach foram administrados misturados à ra o a 8 suínos em doses únicas de 5-20g/kg. Diarréia passageira foi o único sinal nos 2 suínos que consumiram 5g/kg. Os sinais clínicos observados nos animais que ingeriram doses únicas de 10, 15 e 20g/kg caracterizaram-se por incoordena o, tremores musculares, dificuldade para manter-se de pé, relutancia para levantar-se, decúbito esternal e hipotermia. Os 2 suínos que ingeriram 20g/kg morreram. Macroscopicamente observou-se congest o do intestino delgado e da mucosa do est mago. As altera es histológicas caracterizaram-se por discreta a moderada necrose do tecido linfático, necrose dos músculos esqueléticos, congest o e necrose da mucosa gástrica e do intestino delgado e altera es degenerativas moderadas no fígado e rim. Os níveis séricos de AST e CPK aumentaram após a ingest o do tóxico. Observaram-se valores altos de CPK nos animais que morreram, evidenciando a mionecrose. Os resultados obtidos demonstram que, para suínos, a ingest o de altas doses de frutos de Melia azedarach induz ao aparecimento de sinais clínicos da intoxica o e causa les es em diversos órg os, inclusive a morte.
Experimental intoxication by the leaves of Melia azedarach (Meliaceae) in cattle
Carmen Méndez, Maria del;Arag?o, Marcos;Fabiana, Elias;Riet-Correa, Franklin;Juan Gimeno, Eduardo;
Pesquisa Veterinária Brasileira , 2002, DOI: 10.1590/S0100-736X2002000100005
Abstract: green leaves of melia azedarach were administered at single doses ranging from 5 to 30 g/kg bw to 11 calves. clinical signs were depression, ruminal stasis, dry feces with blood, ataxia, muscle tremors, sternal recumbency, hypothermia and abdominal pain. serum ast and cpk were increased. signs appeared from 8 to 24 hours after dosing, and the clinical course lasted from 2 to 72 hours. three calves dosed with 30g/kg bw died. the macroscopic findings included intestinal congestion, yellow discoloration of the liver, brain congestion and dry feces with blood in the rectum. the liver showed swollen and vacuolated hepatocytes. necrotic hepatocytes were scattered throughout the parenchyma or concentrated in the periacinar zone. degenerative and necrotic changes were observed in the epithelium of the forestomachs. there was also necrosis of the lymphoid tissue. skeletal muscles showed hyaline degeneration and fiber necrosis. the necrotic fragments contained floccular or granular debris with infiltration by macrophages and satellite cells.
Fenologia de quatro espécies tóxicas de Senecio (Asteraceae) na regi?o Sul do Rio Grande do Sul
Karam, Fernando Sérgio Castilhos;Carmen Méndez, Maria del;Jarenkow, Jo?o André;Riet-Correa, Franklin;
Pesquisa Veterinária Brasileira , 2002, DOI: 10.1590/S0100-736X2002000100007
Abstract: this study aimed to determine the phenology of senecio brasiliensis, s. oxyphyllus, s. heterotrichius and s. selloi, and their relationship with cattle poisoning in the southern region of the state of rio grande do sul, brazil. the phenology was studied during two years in the rural area of the municipalities of bagé and cap?o do le?o. these phenological observations were made at monthly intervals during the vegetative phase, and every 15 days during the reproductive period. the plants were observed from emergence until the dispersal of seeds, considering their vigor and their relationship with environmental factors. the results indicate that whenever the environmental conditions, like moisture and light, were favorable, senecio spp emerge. the vegetative phenophases are practically constant during all life cycle of the plant and the whole year. unfavorable environmental factors like water stress, soil management and damage by insects, associated or not, can alter the cycle of the plants and determine their permanence in the environment. the majority of the species studied behaved like annual and monocarpic plants. according with the permanence during the two years of observation, the most persistent species in the environment was s. heterotrichius (15% of the plants persisted during the two year period), followed by s. selloi (2,8%) and s. brasiliensis (0,9%). s. oxyphyllus did not persist for more than one year.
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