oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 917 )

2018 ( 1296 )

2017 ( 1242 )

2016 ( 1772 )

Custom range...

Search Results: 1 - 10 of 735475 matches for " Luis M. Mejía-Mendoza "
All listed articles are free for downloading (OA Articles)
Page 1 /735475
Display every page Item
New Approaches to the Computer Simulation of Amorphous Alloys: A Review
Ariel A. Valladares,Juan A. Díaz-Celaya,Jonathan Galván-Colín,Luis M. Mejía-Mendoza,José A. Reyes-Retana,Renela M. Valladares,Alexander Valladares,Fernando Alvarez-Ramirez,Dongdong Qu,Jun Shen
Materials , 2011, DOI: 10.3390/ma4040716
Abstract: In this work we review our new methods to computer generate amorphous atomic topologies of several binary alloys: SiH, SiN, CN; binary systems based on group IV elements like SiC; the GeSe 2 chalcogenide; aluminum-based systems: AlN and AlSi, and the CuZr amorphous alloy. We use an ab initio approach based on density functionals and computationally thermally-randomized periodically-continued cells with at least 108 atoms. The computational thermal process to generate the amorphous alloys is the undermelt-quench approach, or one of its variants, that consists in linearly heating the samples to just below their melting (or liquidus) temperatures, and then linearly cooling them afterwards. These processes are carried out from initial crystalline conditions using short and long time steps. We find that a step four-times the default time step is adequate for most of the simulations. Radial distribution functions (partial and total) are calculated and compared whenever possible with experimental results, and the agreement is very good. For some materials we report studies of the effect of the topological disorder on their electronic and vibrational densities of states and on their optical properties.
Culture Mixed-Sex and Monosex of Tilapia in Ponds in Mexico City  [PDF]
Jose Luis Gómez-Márquez, Bertha Pe?a-Mendoza, María del Carmen Alejo-Plata, José Luis Guzmán-Santiago
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.62017
Abstract: In this study, the growth of Oreochromis niloticus both mixed sex and males sexually reversed were analyzed in concrete ponds in the FES Zaragoza, UNAM, under the environmental conditions of the Mexico City. The experiment was carried from May to November 2013, in two concrete ponds of 50 m2. Similar feeding regime and stocking density of fish were maintained for the culture systems. Different growth parameters like body weight, length, daily weight gain (DWG), specific growth rate (SGR), feed conversion rate (FCR), Fulton’s condition index (K) and survival were analyzed during six months culture period. It was found that culture with monosex males tilapias yielded the highest weight, length, DWG and SGR compared to mixed sex populations tilapias. Water quality was monitored along the experiment. Based on the results, there were statistically significant differences in size (W = 20942.5, p < 0.05) and weight (W = 21413.0, p < 0.05) between the divisions of the pond. The initial total length used was 1.2 cm and ended with 20.4 cm for monosex males, higher than mixed-sex population. The initial average body weight of the fish was 0.21 g and they recorded 192.2 g at the end of culture for monosex males. The weight-length relationship for both populations of fish was positive allometric. The percentage gain in body weight and total length averaged were 150% and 31.8% respectively. Specific growth rates in weight and length for monosex males were higher than mixed-sex population. Daily weight gain and size was similar in both populations. The FCR had a mean value of 1.9:1 for monosex males and condition factor (K) had an average of 1.45 for mixed-sex population. Water quality indicated good oxygenation (>5 mg/L), warm water (>20°C), productive (<100 mg/L CaCO3) and slightly basic (pH > 8). Acceptable growth of fish and a yield of 3 ton/ha/6 months were obtained in both two ponds; therefore, the culture of tilapia under conditions of Mexico City was recommended.
Age and growth of the tilapia, Oreochromis niloticus (Perciformes: Cichlidae) from a tropical shallow lake in Mexico
Gómez-Márquez,José Luis; Pe?a-Mendoza,Bertha; Salgado-Ugarte,Isaías H; Arredondo-Figueroa,José Luis;
Revista de Biología Tropical , 2008,
Abstract: age and growth of nile tilapia (oreochromis niloticus) were determined using 1 039 specimens collected in a tropical shallow lake of mexico, from january to december 1993. standard length of females ranged from 9.0 to 16.5 cm and males from 8.9 to 14.8 cm. the standard length-weight relationships for all individuals was bw=0.1207 sl2.469. the age data, derived from opercular bone readings, were used to estimate the growth parameters of the von bertalanffy equation: =17.88 cm, k=0.3409, to=-1.543, and w=149.21 g. the oldest male and female were 2.5 years old. the sex ratio (female:male) was of 1:1 (x2=0.02, p>0.05). rev. biol. trop. 56 (2): 875-884. epub 2008 june 30.
Reproduction of the fish Poeciliopsis gracilis (Cyprinodontiformes: Poeciliidae) in Coatetelco, a tropical shallow lake in Mexico
Gómez-Márquez,José Luis; Pe?a-Mendoza,Bertha; Salgado-Ugarte,Isaías H; Sánchez-Herrera,Abby K; Sastré-Baez,Leonardo;
Revista de Biología Tropical , 2008,
Abstract: a reproductive analysis of 1 225 specimens of poeciliopsis gracilis obtained through monthly samples from coatetelco, a tropical shallow lake in central mexico, was made. there was an evident sexual dimorphism, including a difference in body size at the onset of reproduction. sex ratio deviated significantly from unity. monthly variations in gonadosomatic (gsi), hepatosomatic (hsi) indexes and ovarian development stages showed that the spawning season was from july to october, coinciding with the rainy season and phytoplankton biomass increase. the largest sizes were 50 mm for females and 43 mm for males. rev. biol. trop. 56 (4): 1801-1812. epub 2008 december 12.
Reproduction of the fish Poeciliopsis gracilis (Cyprinodontiformes: Poeciliidae) in Coatetelco, a tropical shallow lake in Mexico
José Luis Gómez-Márquez,Bertha Pe?a-Mendoza,Isaías H Salgado-Ugarte,Abby K Sánchez-Herrera
Revista de Biología Tropical , 2008,
Abstract: A reproductive analysis of 1 225 specimens of Poeciliopsis gracilis obtained through monthly samples from Coatetelco, a tropical shallow lake in Central Mexico, was made. There was an evident sexual dimorphism, including a difference in body size at the onset of reproduction. Sex ratio deviated significantly from unity. Monthly variations in gonadosomatic (GSI), hepatosomatic (HSI) indexes and ovarian development stages showed that the spawning season was from July to October, coinciding with the rainy season and phytoplankton biomass increase. The largest sizes were 50 mm for females and 43 mm for males. Rev. Biol. Trop. 56 (4): 1801-1812. Epub 2008 December 12. Se realizó el análisis reproductivo de 1 225 organismos de Poeciliopsis gracilis que se obtuvieron de manera mensual en el lago Coatetelco, un cuerpo somero tropical en México. Se hizo evidente un dimorfismo sexual en las características morfológicas de esta especie. Se observó una diferencia en el tama o corporal entre los sexos al inicio de la reproducción. La proporción sexual fue diferente de uno. Con base en la variación mensual del índice gonadosomático (IGS), hepatosomático (IHS) y los estadios de madurez gonádica, se observó que la época de reproducción de P. gracilis se realiza entre julio y octubre, que coincide con la época de lluvias e incremento de la biomasa del fitoplancton. La talla más grande registrada fue de 50 mm para las hembras y de 43 mm para los machos.
Spanish validation of the "Kidney Transplant Questionnaire": a useful instrument for assessing health related quality of life in kidney transplant patients
Pablo Rebollo, Francisco Ortega, Teresa Ortega, Covadonga Valdés, Mónica García-Mendoza, Ernesto Gómez
Health and Quality of Life Outcomes , 2003, DOI: 10.1186/1477-7525-1-56
Abstract: Prospective study of 31 patients on transplant waiting list who received the first kidney. Patients were evaluated before transplant and after 1, 3, 6 and 12 months, using the KTQ and the SF-36 Health Survey. Feasibility, validity, reliability, and sensibility to change were evaluated.Mean time of administration of the KTQ was 12 minutes. Correlation coefficients among KTQ dimensions range between 0.32 and 0.72. Correlation coefficients of KTQ dimensions with SF-36 PCS were low (r<0.4), and with SF-36 MCS were moderate-high (r>0.4) except for Physical Symptom dimension (r = 0.33). Cronbach's Alpha was satisfactory for all KTQ dimensions (Physical Symptoms = 0.80; Fatigue = 0.93; Uncertainty/Fear = 0.81; Emotional= 0.90) except Appearance (0.69). Intraclass correlation coefficients ranged between 0.63 and 0.85, similar to those of the original KTQ version.Results of validation study show that feasibility, validity, reliability and sensibility to change of the Spanish version of the KTQ are similar to those of the original version.The evaluation of Health Related Quality of Life (HRQoL) in chronic diseases is becoming more and more important. The reasons for the importance of HRQoL assessment can be summarized as follows [1]: 1° to determine the efficacy of medical intervention; 2° to improve the process of making clinical decisions; 3° to evaluate the quality of care; 4° to estimate the health care need of the general population; and 5° to gain a better understanding of the causes and consequences of the differences in health. For some authors [2] the assessment of perceived health status is especially important in the evaluation of the consequences of chronic diseases, because clinicians require information about the effects of a specific disease on patients, and also of the effect of a specific treatment, in order to improve its management and the assessment of the evolution of the patient.In the Nephrology field, the evaluation of HRQoL involves: 1st determining t
Reproductive aspects of Oreochromis niloticus (Perciformes: Cichlidae) at Coatetelco lake, Morelos, Mexico
Gómez-Márquez,J.L.; Pe?a-Mendoza,B.; Salgado-Ugarte,I.H.; Guzmán-Arroyo,M.;
Revista de Biología Tropical , 2003,
Abstract: sex ratio, size at maturity, maturity stages, fecundity and egg diameter of oreochromis niloticus from coatetelco lake, morelos state, mexico, were studied from january to december 1993. sex ratio (male:female) was approximately 1:1.02. length at maturity was 117 mm (males) and 120 mm (females). the fecundity ranged between 104 and 709 eggs, with egg diameter from 1 000 to 3 000 μm. the gonadosomatic and hepatosomatic index indicate that the species breeds during summer and winter.
Reproductive aspects of Oreochromis niloticus (Perciformes: Cichlidae) at Coatetelco lake, Morelos, Mexico
J.L. Gómez-Márquez,B. Pe?a-Mendoza,I.H. Salgado-Ugarte,M. Guzmán-Arroyo
Revista de Biología Tropical , 2003,
Abstract: Sex ratio, size at maturity, maturity stages, fecundity and egg diameter of Oreochromis niloticus from Coatetelco Lake, Morelos State, Mexico, were studied from January to December 1993. Sex ratio (male:female) was approximately 1:1.02. Length at maturity was 117 mm (males) and 120 mm (females). The fecundity ranged between 104 and 709 eggs, with egg diameter from 1 000 to 3 000 μm. The gonadosomatic and hepatosomatic index indicate that the species breeds during summer and winter. En este estudio se analizaron algunos aspectos reproductivos de la mojarra-tilapia Oreochromis niloticus L. en el lago de Coatetelco, Morelos. La información esta basada en los datos biológicos de 319 organismos obtenidos de enero a diciembre de 1993 de la captura comercial. Las hembras (161) representaron el 51% y los machos (158) el 49 % del total de la población. La proporción de sexo fue de 1:1.02 _ = 0.02; p=0.05). Los peces alcanzan la primera madurez sexual a los 117 mm y 120 mm de longitud total (hembras y machos respectivamente). El número de óvulos presentes en las gónadas osciló entre 104 y 709 con diámetro de 1 000 a 3 000 μm, lo cual hace que esta especie tenga baja fecundidad pero alta fertilidad por los hábitos de reproducción que presenta la especie. Se aplicó el indice gonadosomático y hepatosomático con los cuales se detectaron dos períodos (verano e invierno) de máxima actividad reproductiva.
Reproductive biology of Oreochromis niloticus (Perciformes: Cichlidae) at Emiliano Zapata dam, Morelos, Mexico
Pe?a-Mendoza,B; Gómez-Márquez,J.L; Salgado-Ugarte,I.H; Ramírez-Noguera,D;
Revista de Biología Tropical , 2005,
Abstract: the reproductive season of tilapia was studied by monthly samplings at emiliano zapata dam, morelos state, mexico. from february 1999 through february 2000 a sample of 50 fish was taken from the commercial catch (castnet, 6.5 cm of mesh size). the observed sex ratio was 1:1.29 (females:males) (??2=10.26; p<0.05). the tilapia reached maturity at 151.3 mm (females) and 152.0 mm (males) of total length. rainy (august) and dry (february) seasons were determined as the breeding period. fecundity variation was better correlated with length (r=0.7473; p<0.002) than with weight (r=0.7395; p<0.002). the fecundity ranged between 243 and 847 oocytes per fish, with egg diameter from 300 to 3 700 μm. intensive breeding activity in august and february coincide with phytoplankton biomass increase. rev. biol. trop. 53(3-4): 515-522. epub 2005 oct 3.
Reproductive biology of Oreochromis niloticus (Perciformes: Cichlidae) at Emiliano Zapata dam, Morelos, Mexico
B Pe?a-Mendoza,J.L Gómez-Márquez,I.H Salgado-Ugarte,D Ramírez-Noguera
Revista de Biología Tropical , 2005,
Abstract: The reproductive season of tilapia was studied by monthly samplings at Emiliano Zapata dam, Morelos State, Mexico. From February 1999 through February 2000 a sample of 50 fish was taken from the commercial catch (castnet, 6.5 cm of mesh size). The observed sex ratio was 1:1.29 (females:males) ( 2=10.26; p<0.05). The tilapia reached maturity at 151.3 mm (females) and 152.0 mm (males) of total length. Rainy (August) and dry (February) seasons were determined as the breeding period. Fecundity variation was better correlated with length (r=0.7473; p<0.002) than with weight (r=0.7395; p<0.002). The fecundity ranged between 243 and 847 oocytes per fish, with egg diameter from 300 to 3 700 μm. Intensive breeding activity in August and February coincide with phytoplankton biomass increase. Rev. Biol. Trop. 53(3-4): 515-522. Epub 2005 Oct 3. Se analizó la biología reproductiva de la tilapia en la presa Emiliano Zapata, Morelos, México. Para esto se realizaron muestreos de febrero 1999 a febrero 2000. Se tomaron 50 organismos mensuales de la captura comer-cial obtenidos con una atarraya de 6.5 cm de luz de malla. La proporción sexual fue de1:1.29 hembras:machos (X2=10.26; p<0.05). La madurez sexual se alcanza a los 151.3 mm (hembras) y a los 152.0 mm (machos) de longi-tud total. Se detectaron dos épocas de reproducción para la especie: durante la estación lluviosa (agosto) y durante la estación de secas (febrero). La fecundidad relativa presentó mayor correlación con la longitud (r=0.7473; p<0.002) que con el peso (r=0.7395; p<0.002). Por otra parte, el intervalo para la fecundidad osciló entre 243 y 847 ovocitos por pez, con diámetros de 300 a 3 700 μm. Asimismo, la actividad reproductiva de la especie en Agosto y Febrero, coincide con el incremento de biomasa fitoplanctónica.
Page 1 /735475
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.