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Search Results: 1 - 10 of 209299 matches for " Dina L. López "
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Chemical and Geological Control on Surface Water within the Shade River Watershed in Southeastern Ohio  [PDF]
Prosper Gbolo, Dina L. López
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.41001
Abstract:

The under-sampled middle and western branches of Shade River Watershed (SRW) in SE Ohio were investigated as part of the Ohio University—U.S. Environmental Protection Agency (EPA) STAR grant. This project was for monitoring the quality of watersheds in Ohio and classifying them according to their physical, chemical, and biological conditions. Water samples, as well as field parameters, were taken at twenty-two sites for chemical analyses. The ions analyzed included Ca, Mg, Na, Fe, Mn, Al, NO3, SO4, HCO3, and total PO4, while the field parameters measured included pH, dissolved oxygen (DO), total dissolved solids (TDS), electrical conductivity (EC), and alkalinity. To assess the water quality within the SRW, the analyzed ions and field parameters were compared to the USEPA criteria for the survival of aquatic life. Analytical results showed that the watershed is dominated by Ca-HCO3waters with DO, Fe, Mn, and PO4being the main causes of impairment within the streams. The relatively elevated concentrations of manganese and less extent iron may be associated with the local geology and the acidic nature of the soils. The high alkalinity and calcium concentrations are due to the limestone geology. The elevated phosphate concentration may be due to anthropogenic sources, fertilizers, or contributions from phosphorus-rich bedrock that differs geochemically from other areas.

Pesticide-Handling Practices in Agriculture in El Salvador: An Example from 42 Patient Farmers with Chronic Kidney Disease in the Bajo Lempa Region  [PDF]
Roberto Mejía, Edgar Quinteros, Alejandro López, Alexandre Ribó, Humberto Cedillos, Carlos M. Orantes, Eliette Valladares, Dina L. López
Occupational Diseases and Environmental Medicine (ODEM) , 2014, DOI: 10.4236/odem.2014.23007
Abstract:

Introduction: The occupational toxic risks from agricultural activities in El Salvador affect human and environmental health. The objective of this paper is to describe the management of pesticide by farmers confirmed with a chronic kidney disease of uncertain etiology (CKDu) not associated to diabetes mellitus or hypertension. Methods: The study involved 42 male patients older than 18 years old with confirmed CKDu that have participated in different stages of pesticides management. This is a cross-sectional study; it was conducted from January to June 2011, in three communities of Bajo Lempa region, El Salvador. An interview was especially designed to investigate which pesticides were used and the farmer practices at different stages of pesticide use. Statistical descriptive analysis was carried out for the several studied variables. Results: All interviewed people had a direct relationship with agricultural activities. The majority of patients had poor education, 19% were illiterate and 55% only have primary education. Most farmers with CKDu had been exposed more than 10 years to hazardous pesticides. The most used pesticide was Hedonal/2, 4 D (100%). 95% interviewed patients mixed different pesticides and 63% dumped empty pesticide containers in the fields. Interviewees did not use appropriate personal protective equipment (100%). Conclusions: There is high use of hazardous pesticides by patients and some of these are banned and some are legal in El Salvador, but prohibited by other countries. Interviewed CKDu patients had high exposure to toxic pesticides due to the misuse in almost all stages. There is inadequate legislation and a poor law enforcement to prevent the misuse of pesticides in El Salvador.

Effects of High Plant Protein and High Soluble Fiber Beverages on Satiety, Appetite Control and Subsequent Food Intake in Healthy Men  [PDF]
Dina Fernández-Raudales, Mike Yor-Aguilar, Jose Andino-Segura, Adriana Hernández, Russ Egbert, Julio R. López-Cintrón
Food and Nutrition Sciences (FNS) , 2018, DOI: 10.4236/fns.2018.96057
Abstract: Plant based proteins and fibers are attractive ingredients for weight management-dietary preventive strategies due to their positive satiety enhancement effects. The objective of this study was to evaluate the effect of beverages high in plant-protein and soluble fiber on satiety, appetite, hunger and subsequent food intake in healthy young men. This was a randomized crossover study with 30 normal weight male participants, BMI 23.6 ± 1.6 and age 22 ± 1.4. Volunteers consumed one high carbohydrates control (B) and 3 treatments on different days with 3-day washout period. Beverages had similar viscosity and energy content (238 ± 3.8 Kcal). The blank contained (B)-0 g protein/2g fiber), High protein (HP)-30 g protein/2g fiber, High Fiber (HF)-0 g protein/11g fiber and High protein high fiber beverage (HPHF)-30g protein/11g fiber. Visual Analogue Scales VAS were used for subjective satiety, hunger and appetite. Subsequent energy and macronutrient intake was measured by difference after consuming lunch ad libitum. Beverages HP, HF and HPHF showed higher satiety effect than B after 2 and 3 hours post consumption (P = 0.02). HP showed the most prolonged effect on satiety (4 h) compared to the control (P = 0.02). Appetite control was not different between treatments but significant differences were observed against the control after 2 h of consumption (P = 0.01). No differences on hunger perception, subsequent energy or macronutrient intake were observed among all beverages (P > 0.05). The current study demonstrates that HPHF, HP and HF beverages led to improved satiety over high carbohydrate beverages. In conclusion, beverages formulated with plant-based proteins, soluble corn fiber or both may be an effective strategy to promote satiety as part of an overall weight management plan.
MODELACIóN GEOQUíMICA DEL AGUA SUBTERRáNEA EN UN SITIO DE DISPOSICIóN FINAL DE RESIDUOS SóLIDOS URBANOS
Francisco Javier GóMEZ-PUENTES,Jaime Alonso REYES-LóPEZ,Dina L-LóPEZ,Salvador BELMONTE-JIMéNEZ
Revista internacional de contaminación ambiental , 2012,
Abstract: Entre las fuentes potenciales de contaminación de aguas subterráneas se encuentra la migración de contaminantes desde sitios no controlados de disposición final de los residuos sólidos urbanos. Uno de estos sitios es el tiradero Vado Carranza, localizado en el Valle de Mexicali, B. C. en el noroeste de México, el cual está en operación desde hace quince a os y recibe alrededor de 30 Mg/día de residuos sólidos. Las características de operación de este sitio, entre ellas la disposición y la quema a cielo abierto de los residuos, aunado a la poca profundidad del acuífero de la zona, hacen vulnerables a padecer procesos de contaminación tanto al suelo como al agua subterránea. En esta investigación se llevó a cabo la modelación geoquímica del agua subterránea mediante el programa PHREEQC con el objeto de estimar su evolución geoquímica en el área del tiradero. Para ello se tomaron como base tanto la dirección de flujo así como los parámetros físicos y químicos medidos en la red piezométrica instalada en el acuífero somero. Los resultados de la modelación sugieren como procesos importantes los siguientes: evaporación de agua, intercambio catiónico y adsorción de metales.
Respuesta al tratamiento antituberculosis en pacientes con historia de tratamientos previos en el Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas
Martínez, Dina;Salazar Lezama, Miguel ángel;Castillejos López, Manuel de Jesús;García Sancho Figueroa, Ma. Cecilia;
Revista del Instituto Nacional de Enfermedades Respiratorias , 2006,
Abstract: background: the national institute of respiratory diseases ismael cosío villegas (iner) is a national third level referral center for all respiratory diseases, including multitreaded pulmonary tuberculosis patients (ptb). the purpose of this study was to evaluate the results of supervised ptb retreatment at the iner in patients previously treated for ptb. methods: retrospective review of clinical charts by a standardized questionary of previous treated ptb patients and whose new treatment was given and supervised al the iner from 1994 to 2001. the response was analyzed according to the number of previous treatments, history of failure to previous treatments and presence or absence of mdr ptb. results: one hundred and forty seven patients had previously received treatment for ptb. the cure rates for patients with one, two, three or more previous ptb treatments were 68.2%, 40.4%, and 8.8% (p = 0.009); desertion 6.8%, 4.3%, and 3.1% (p = 0.7); failure 18.2%, 27.7%, and 25 % (p = 0.6) for each one of the groups, respectively. the proportion of mdr- ptb was 64.4%, 86.3%, and 94.4% in each group (x2 trend, p = 0.0004). a previous treatment failure was a predictor of failure of treatment at the iner [or = 2.4 (ci95% 0.9-9.64), p = 0.04]. according to resistance, cure rates were 71.4% for one drug resistance, mdr 44.9% and poly resistance 30.8% (x2 trend, p= -03). conclusions: for patients with one or more failed previous treatments for ptb, receiving a new supervised treatment regime at the iner, there were low cure rates, a high proportion of treatment failures and a high rate of mdr-ptb.
Biología y comportamiento sexual del mutante ojos amarillos de Anastrepha Ludens (Diptera: Tephritidae)
QUINTERO-FONG, José Luis;MEZA-HERNáNDEZ, José Salvador;OROZCO-DáVILA, Dina;FIGUEROA, Miguel Salvador;CRUZ-LóPEZ, Leopoldo;
Acta zoológica mexicana , 2009,
Abstract: we compared the biology and sexual behavior between a strain of laboratory with wild phenotype (lfs) and a strain of laboratory with mutant phenotype (lfm) of anastrepha ludens (loew), characterized by clear coloration of the body and creamy yellow eyes to determine their potential as genetic marker in the control programmes through the use of the sterile insect technique. the survey results indicated that individuals of the lfm mutant strain not differ significantly from individuals of the lfs strain respect to their fecundity, fertility and survival of immature stages, as well as in the emission of sexual pheromone. this indicates that could be adapted to mass-rearing. however, mating tests indicated that although the lfm insects mated with the insects of field of wild phenotype (cfs), presented some degree of isolation and low percentages of mating of males with both lfs and cfs females, implying that is not recommended the use of the lfm mutant strain as genetic marker in programs that use the sterile insect technique, for the control of the mexican fruit fly.
Study of Decoherence of Elementary Gates Implemented in a Chain of Few Nuclear Spins Quantum Computer Model  [PDF]
G. V. López, P. López
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.31013
Abstract: We study the phenomenon of decoherence during the operation of one qubit transformation, controlled-not (CNOT) and controlled-controlled-not (C2NOT) quantum gates in a quantum computer model formed by a linear chain of three nuclear spins system. We make this study with different type of environments, and we determine the associated decoherence time as a function of the dissipative parameter. We found that the dissipation parameter to get a well defined quantum gates (without significant decoherence) must be within the range of . We also study the behavior of the purity parameter for these gates and different environments and found linear or quadratic decays of this parameter depending on the type of environments.
Study of Decoherence on the Teleportation Algorithm in a Chain of Three Nuclear Spins System  [PDF]
G. V. López, P. López
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.41012
Abstract:

We make a numerical study of decoherence on the teleportation algorithm implemented in a linear chain of three nuclear spins system. We study different types of environments, and we determine the associated decoherence time as a function of the dissipative parameter. We found that the dissipation parameter to get a well defined quantum gates (without significant decoherence) must be within the range of γ4×10-4 for not thermalized case, which was determined by using the purity parameter calculated at the end of the algorithm. For the thermalized case the decoherence is stablished for very small dissipation parameter, making almost not possible to implement this algorithm for not zero temperature.

On the Quantization of One-Dimensional Conservative Systems with Variable mass  [PDF]
G. V. López
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.38102
Abstract: The Hamiltonian associated to the mass variable system is constructed from first principles through finding a constant of motion of the system. A comparison is made of the classical motion of a body with its mass position depending in the (x,v) space and (x,p) space which are defined by the constant of motion and the Hamiltonian, for a particular model of mass variation. As one could expected, these motion looks different on these spaces. The quantization of the harmonic oscillator with this mass variation is done, and a comparison is made by using the usual Hamiltonian approach with the proposed quantization of the constant of motion approach. This comparison is done at first order in perturbation theory, and one sees a difference between both approaches which can, in principle, be measured.
Generalization of the Force Approach to Radiation Reaction  [PDF]
Gustavo V. López
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.53048
Abstract: A new approach to radiation reaction for the correction of the linear and circular motion of a charged particle takes into account the emission of electromagnetic radiation due to its acceleration. This new formulation was based on expressing the radiation reaction force in terms of the external force rather than the acceleration of the charge. In this paper, a generalization of the radiation reaction force in terms of the external force approach is formulated for any arbitrary motion of the charged particle. This generalization includes the linear and circular acceleration cases previously investigated.
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