Isai Lopez - Academia.edu (original) (raw)
Papers by Isai Lopez
The California Horn Snail (Cerithideopsis californica) is an important primary intermediate host ... more The California Horn Snail (Cerithideopsis californica) is an important primary intermediate host in the life cycle of a variety of parasitic species that have extensive effects on ecological food webs. As such, parasite load in the California Horn Snail can serve as an important tool in assessing the effectiveness of restoration projects. The goal of the study was to investigate the population dynamics of the California Horn Snail in Ballona Wetlands, California, the only major coastal salt marsh in Los Angeles County. This study evaluated the spatial dispersion, size distribution, and density of C. californica collected from the Ballona Wetlands Ecological Preserve. The results showed that the population of C. californica in the preserve exhibited a bimodal distribution of size, with the large and small cohorts exhibiting significantly different patterns of dispersion. The study suggests that both bimodal size distribution and size-associated behavior of C. californica may be impor...
Información del libro El Cid, mito y realidad. Los caminos: Museu de Prehistòria i de les Culture... more Información del libro El Cid, mito y realidad. Los caminos: Museu de Prehistòria i de les Cultures de València, del 28 de marzo al 30 de abril de 2000.
Journal of Food Engineering, 2004
Theoretical moisture and temperature evolution during carrot slab drying were estimated with non-... more Theoretical moisture and temperature evolution during carrot slab drying were estimated with non-steady heat and mass transfer equations using constant and variable properties. Experimental drying kinetics of carrot slabs were obtained in order to compare with estimations. The results showed that moisture evolution, estimated for constant properties, reproduces approximately the experimental one, with deviations of experimental shape. Moisture evolution estimation for variable properties reproduces the experimental shape, but numerical effort is considerably increased. Temperature evolution is sensitive with respect to properties functions. This paper shows that constant properties assumption has application for engineering purposes and variable properties gives more phenomenological information for further predictions.
Journal of Food Engineering, 2008
A heat and mass transfer model in prolate spheroidal coordinates system was proposed to describe ... more A heat and mass transfer model in prolate spheroidal coordinates system was proposed to describe the drying of green coffee beans. The model describes the 3D moisture and temperature profiles inside the bean. The results were integrated over volume in order to obtain a drying kinetic equation for prolate spheroidal geometry. The average effective diffusivity of water as function of temperature and moisture was estimated at 45 and 60°C by slope method from experimental drying kinetic of green coffee beans. The expression obtained applied to drying kinetic equation reproduced approximately the experimental behavior.
Journal of Applied Phycology, 2008
The effect of several alkali treatments on the yield, gel strength, rheology, and chemical charac... more The effect of several alkali treatments on the yield, gel strength, rheology, and chemical characteristics (quality) of the agar obtained from Gracilariopsis lemaneiformis from the Gulf of California was analyzed using different alkali concentrations, temperatures and treatment times. In the first stage of the experiment, all treatments lasted 60 min and the NaOH concentrations (2.5, 3.0, 4.0, 5.0, 6.0%) and temperature (80, 90, 100°C) varied. At constant time, temperature played the predominant role, promoting an increase in agar gel strength. Based on the best treatment conditions found (4% and 5% NaOH, and 90°C and 100°C temperature), in the second stage different treatment times (15, 30, 60, 90, 120 min) were used. Since agar yields were not significantly different among temperatures and times, the optimal conditions to obtain best quality agar were those providing the highest gel strength. Treatment time played an important role in increasing gel strength. Maximum gel strength (Nikan, 954 g cm −2) was obtained with 5% NaOH at 100°C after 90 min of treatment, though these conditions resulted in an agar yield reduction of 25.5% relative to native agar. This treatment proved to efficiently yield G. lemaneiformis agar that will meet the commercial quality requirements regarding gel strength, 3,6 anhydrogalactose and sulfate content, as well as rheology and hysteresis.
European Journal of Neurology, 2007
Histamine has a selective affinity for H3‐receptors and it may specifically inhibit the neurogeni... more Histamine has a selective affinity for H3‐receptors and it may specifically inhibit the neurogenic edema response involved in migraine pathophysiology. The objective of this study was to evaluate the therapeutic potential of subcutaneous administration of histamine in migraine prophylaxis, compared with oral administration of sodium valproate, in an open clinical trial. Ninety‐two patients with migraine were selected under criteria established by the International Headache Society and enrolled in a 12‐week double‐blind controlled clinical trial to evaluate the efficacy of subcutaneous administration of histamine (1–10 ng twice a week; n = 46) compared with oral administration of sodium valproate (500 mg daily dose; n = 46). The variables studied were headache intensity, frequency, duration, analgesic intake and migraine disability assessment (MIDAS). Two‐tailed Student's t‐ test was used to compare means and the Mann–Whitney U and anova tests were used. The data collected during...
Impacto Cientifico, 2012
El trabajo que se presenta tiene por finalidad proponer la Coordinación de Prácticas Profesionale... more El trabajo que se presenta tiene por finalidad proponer la Coordinación de Prácticas Profesionales en el Programa Ciencias Económicas y Sociales del Núcleo Costa Oriental del Lago de la Universidad del Zulia. A través de las prácticas profesionales se pretende familiarizar al estudiante con los ambientes, actividades y tareas propias de la profesión, así como también con los instrumentos y sus diferentes campos de acción, además de los conocimientos necesarios para desarrollar la capacidad creativa e innovadora, de manera que pueda hacer frente a la realidad del país, participando en la dinámica de los procesos económicos, políticos y social-ambiental. Se espera que con la coordinación propuesta se logre la integración de la universidad con el sector productivo en la Costa Oriental del Lago en el estado Zulia.
The California Horn Snail (Cerithideopsis californica) is an important primary intermediate host ... more The California Horn Snail (Cerithideopsis californica) is an important primary intermediate host in the life cycle of a variety of parasitic species that have extensive effects on ecological food webs. As such, parasite load in the California Horn Snail can serve as an important tool in assessing the effectiveness of restoration projects. The goal of the study was to investigate the population dynamics of the California Horn Snail in Ballona Wetlands, California, the only major coastal salt marsh in Los Angeles County. This study evaluated the spatial dispersion, size distribution, and density of C. californica collected from the Ballona Wetlands Ecological Preserve. The results showed that the population of C. californica in the preserve exhibited a bimodal distribution of size, with the large and small cohorts exhibiting significantly different patterns of dispersion. The study suggests that both bimodal size distribution and size-associated behavior of C. californica may be impor...
Información del libro El Cid, mito y realidad. Los caminos: Museu de Prehistòria i de les Culture... more Información del libro El Cid, mito y realidad. Los caminos: Museu de Prehistòria i de les Cultures de València, del 28 de marzo al 30 de abril de 2000.
Journal of Food Engineering, 2004
Theoretical moisture and temperature evolution during carrot slab drying were estimated with non-... more Theoretical moisture and temperature evolution during carrot slab drying were estimated with non-steady heat and mass transfer equations using constant and variable properties. Experimental drying kinetics of carrot slabs were obtained in order to compare with estimations. The results showed that moisture evolution, estimated for constant properties, reproduces approximately the experimental one, with deviations of experimental shape. Moisture evolution estimation for variable properties reproduces the experimental shape, but numerical effort is considerably increased. Temperature evolution is sensitive with respect to properties functions. This paper shows that constant properties assumption has application for engineering purposes and variable properties gives more phenomenological information for further predictions.
Journal of Food Engineering, 2008
A heat and mass transfer model in prolate spheroidal coordinates system was proposed to describe ... more A heat and mass transfer model in prolate spheroidal coordinates system was proposed to describe the drying of green coffee beans. The model describes the 3D moisture and temperature profiles inside the bean. The results were integrated over volume in order to obtain a drying kinetic equation for prolate spheroidal geometry. The average effective diffusivity of water as function of temperature and moisture was estimated at 45 and 60°C by slope method from experimental drying kinetic of green coffee beans. The expression obtained applied to drying kinetic equation reproduced approximately the experimental behavior.
Journal of Applied Phycology, 2008
The effect of several alkali treatments on the yield, gel strength, rheology, and chemical charac... more The effect of several alkali treatments on the yield, gel strength, rheology, and chemical characteristics (quality) of the agar obtained from Gracilariopsis lemaneiformis from the Gulf of California was analyzed using different alkali concentrations, temperatures and treatment times. In the first stage of the experiment, all treatments lasted 60 min and the NaOH concentrations (2.5, 3.0, 4.0, 5.0, 6.0%) and temperature (80, 90, 100°C) varied. At constant time, temperature played the predominant role, promoting an increase in agar gel strength. Based on the best treatment conditions found (4% and 5% NaOH, and 90°C and 100°C temperature), in the second stage different treatment times (15, 30, 60, 90, 120 min) were used. Since agar yields were not significantly different among temperatures and times, the optimal conditions to obtain best quality agar were those providing the highest gel strength. Treatment time played an important role in increasing gel strength. Maximum gel strength (Nikan, 954 g cm −2) was obtained with 5% NaOH at 100°C after 90 min of treatment, though these conditions resulted in an agar yield reduction of 25.5% relative to native agar. This treatment proved to efficiently yield G. lemaneiformis agar that will meet the commercial quality requirements regarding gel strength, 3,6 anhydrogalactose and sulfate content, as well as rheology and hysteresis.
European Journal of Neurology, 2007
Histamine has a selective affinity for H3‐receptors and it may specifically inhibit the neurogeni... more Histamine has a selective affinity for H3‐receptors and it may specifically inhibit the neurogenic edema response involved in migraine pathophysiology. The objective of this study was to evaluate the therapeutic potential of subcutaneous administration of histamine in migraine prophylaxis, compared with oral administration of sodium valproate, in an open clinical trial. Ninety‐two patients with migraine were selected under criteria established by the International Headache Society and enrolled in a 12‐week double‐blind controlled clinical trial to evaluate the efficacy of subcutaneous administration of histamine (1–10 ng twice a week; n = 46) compared with oral administration of sodium valproate (500 mg daily dose; n = 46). The variables studied were headache intensity, frequency, duration, analgesic intake and migraine disability assessment (MIDAS). Two‐tailed Student's t‐ test was used to compare means and the Mann–Whitney U and anova tests were used. The data collected during...
Impacto Cientifico, 2012
El trabajo que se presenta tiene por finalidad proponer la Coordinación de Prácticas Profesionale... more El trabajo que se presenta tiene por finalidad proponer la Coordinación de Prácticas Profesionales en el Programa Ciencias Económicas y Sociales del Núcleo Costa Oriental del Lago de la Universidad del Zulia. A través de las prácticas profesionales se pretende familiarizar al estudiante con los ambientes, actividades y tareas propias de la profesión, así como también con los instrumentos y sus diferentes campos de acción, además de los conocimientos necesarios para desarrollar la capacidad creativa e innovadora, de manera que pueda hacer frente a la realidad del país, participando en la dinámica de los procesos económicos, políticos y social-ambiental. Se espera que con la coordinación propuesta se logre la integración de la universidad con el sector productivo en la Costa Oriental del Lago en el estado Zulia.