38 research outputs found
Using Desalination to Improve Agricultural Yields: Success Cases in Mexico
Water scarcity is a global problem, motivating growth and development of new technologies for water treatment, reuse and desalination. For many arid regions in Mexico, especially in the northwest, agriculture is an important economic activity. The Yaqui Valley in Sonora, Mexico, faces problems related to aquifer overexploitation and saline intrusion, which have increased salt concentration in well water to 2000–9000 mg/L total dissolved solids (TDS) and led to soil salinization and low crop yields. This work evaluates the effect of TDS in irrigation water on crop yield. A 150 m3/d desalination plant was used, consisting of 12 SWC4B-MAX membrane modules, with 98% rejection and 75% recovery. Two crops were irrigated with control (4000 mg/L) and desalinated water (200 mg/L). Sorghum (Sorghum) had yields of 7.9 and 8.8 ton/ha, whereas tomatillo (Physalis philadelphica) had yields of 30.82 and 35.88 ton/ha, respectively. Evidently, the desalination process influences agricultural yields
Variability and Genetic Structure of the Montezuma Quail Cyrtonyx montezumae in the Northern Limit of its Distribution
A species’ geographic distribution of genetic variability is influenced by different factors including size of geographic distribution, dispersal capability, mating system, and migration. For instance, a low migration rate among populations may cause a decrease in genetic variation. Such is the case of the Montezuma quail (Cyrtonyx montezumae), a popular game bird with a limited flight capacity that prevents long-distance dispersal. In the northern limit of the species’ distribution in Arizona, New Mexico, and Texas in the United States, the species inhabits oak forests that are separated from one another by deserts. Consequently, Montezuma quail populations are distributed in patches or islands. Knowledge of the species’ genetic structure is likely to help inform habitat management decisions. The objective of this study was to determine patterns of genetic variation in populations of the Montezuma quail using 9 microsatellite DNA loci. We genotyped 119 individuals harvested from 4 populations: Arizona (AZ), western New Mexico (WNM), eastern New Mexico (ENM), and west Texas (WTX). Montezuma quail populations had low observed heterozygosity (Ho = 0.22 ± 0.04) and a low number of alleles per locus (A = 2.41 ± 0.27) compared to other quail species. A global population genetic differentiation index (RST) of 0.045 suggests a weak genetic structure. Max(RST) occurred among pairwise comparisons AZ-WTX, AZ-ENM, and WNM-WTX. A Bayesian allocation analysis indicates that individuals were separated into 3 groups (K = 3), placing the populations of Arizona and Texas in distinct groups apart from the 2 populations of New Mexico, which are in the same group. Despite this differentiation, the Bayesian allocation analysis suggests admixture among populations, which may be an indicator of migration between them, especially between the populations in New Mexico and Arizona. An isolation-by-distance analysis indicates that there is a strong correlation (R2 = 0.84) and suggestive evidence (P = 0.08) of non-independence between geographical and genetic distances, though Montezuma quail populations in the southwestern United States may not be isolated. Climate change projections indicate an increase in aridity conditions in this region, especially in temperate ecosystems where the species occurs. In this scenario, corridors between the populations may disappear, thus causing their complete isolation
Impacto de las TICs en el proceso de Aprendizaje de los estudiantes
ICTs are constantly evolving as part of daily life, they have taken a fundamental role in society and particularly in the educational field, so that ICTs are a basic tool in the teaching and learning process. The purpose of this article is to analyze the impact of ICTs in the learning process in students of the PCEI career of the fourth semester of the UTB of the academic period November 2021-April 2022 as well as throughout the article the main advantages and disadvantages that ICTs generate when integrating them in the learning process will be highlighted and at the same time the importance of using ICT tools in the learning process will be established. The methodology used in the research process was descriptive and exploratory. The population and sample surveyed was of 33 students, which resulted in a high degree of conformity, so that the highest percentage of the surveyed population showed that ICTs are essential in their learning process, since through ICTs they can access to various resources that can strengthen their skills. Therefore, it can be concluded that ICTs are essential in the educational field, since their implementation improves educational praxis and contributes to self-learning through the use of different tools, thus allowing students to awaken their curiosity and motivation to learn.Las TICs van evolucionando constantemente formando parte del diario vivir, estas han tomado un papel fundamental en la sociedad y en particular en el ámbito educativo, de manera que las TICs son una herramienta básica en el proceso de enseñanza y aprendizajes. El presente artículo tiene la finalidad de analizar el impacto de las TICs en el proceso de Aprendizaje en los estudiantes de la carrera PCEI del cuarto semestre de la UTB del periodo académico Noviembre 2021-Abril-2022 así como también a lo largo del artículo se destacara las principales ventajas y desventajas que generan las TICs al integrarlas en el proceso de aprendizaje y a su vez se establecerá la importancia de utilizar herramientas TICs en el proceso de aprendizaje. La metodología que se utilizó en el proceso de la investigación fue descriptiva y exploratoria. La población y muestra encuestada fue de 33 estudiantes, la cual se obtuvo como resultado un alto grado de conformidad, de manera que el mayor porcentaje de la población encuestada demostraron que las TICs son fundamentales en su proceso de aprendizaje, ya que por medio de las TICs pueden acceder a diversos recursos que permite fortalecer sus habilidades. Por lo tanto, se logra concluir que las TICs son imprescindible en el ámbito educativo ya que al implementarla mejora la praxis educativa del mismo modo contribuye con el autoaprendizaje a través del uso de diferentes herramientas, permitiendo así al estudiante despertar su curiosidad y motivación por aprender
Efficacy and safety of the metformin-mazindol anorectic combination in rat
The current study investigates the anorectic interaction and safety of the mazindol-metformin combination in rats. Isobologram and interaction index were used to determine anorectic interaction between mazindol and metformin in the sweetened milk model. The safety profile of the mazindol-metformin combination was determined by measuring anxiety, blood pressure, hematic biometry and blood chemistry. An acute dose of mazindol and metformin administered per os, individually or as a mixture, has reduced the milk consumption in rats in a dose-dependent manner. Theoretical effective dose 40 (ED40t) did not differ from the experimental effective dose 40 (ED40e) obtained with the mazindol-metformin mixture in the anorexia experiments, by Student´s t-test. In addition, the interaction index confirmed the additive anorectic effect between both drugs. A single oral dose of ED40e mazindol-metformin mixture induced anxiolysis in the elevated plus-maze test. Moreover, oral administration of mazindol-metformin combination for 3 months significantly decreased glycemia, but not blood pressure nor other parameters of hematic biometry and blood chemistry. Results suggest that mazindol-metformin combination exerts an additive anorectic effect, as well as anxiolytic and hypoglycemic properties. Mazindol-metformin combination might be useful in obese patients with anxiety disorders or diabetes risk factors
N-(4-Methoxy-2-nitrophenyl)hexadecanamide, a palmitoylethanolamide analogue, reduces formalin-induced nociception
Main methods: The formalin test was used to assess the antinociceptive activity of HD in vivo. The hydrolysis of anandamide catalyzed by fatty acid amide hydrolase (FAAH) was used to determine the action of HD on FAAH activity in vitro. Key findings: Local peripheral ipisilateral, but not contralateral, administration of HD (10-100 μg/paw) produced a dose-dependent antinociceptive effect in rats. The CB 1 and CB 2 receptor antagonists AM281 (0.3-30 μg/paw) and SR144528 (0.3-30 μg/paw), respectively, reduced the antinociceptive effect of HD (100 μg/paw). In addition, methiothepin (0.03-0.3 μg/paw) and naloxone (5-50 μg/paw) significantly reduced HD-induced antinociception (100 μg/paw). In vitro, HD reduced only to a minor extent the hydrolysis of anandamide catalyzed by FAAH. Significance: HD local administration produces antinociception that probably results from an indirect activation of peripheral CB 1 and CB 2 cannabinoid receptors. Data suggest that 5-HT 1 and opioid receptors also participate in the antinociceptive effect of this compound. HD may have potential as analgesic drug
Análise do comportamento de solos não saturados a pequenas deformações
Nos últimos anos tem aumentado o interesse no meio geotécnico em relação ao comportamento dos solos a pequenas deformações, sendo que a maioria das pesquisas estão relacionadas a solos saturados, não considerando a influência da sucção na variação do módulo de rigidez do solo (G). Neste trabalho foram realizados ensaios de coluna ressonante em um solo do
canal Alguerry-Balaguery, Espanha, em amostras a diversos teores de umidade, a fim de investigar o comportamento de solos nao saturados a pequenas deformações. Os valores de sucção do solo foram obtidos por meio da curva característica. Verificou-se que o comportamento do módulo de rigidez do solo (G) é elástico-linear apenas para deformações angulares menores que 0,001% e que o mesmo é influenciado pela variação do estado de tensão do solo (tensão média e sucção).Peer ReviewedPostprint (author’s final draft
In Search of Critically Endangered Species: The Current Situation of Two Tiny Salamander Species in the Neotropical Mountains of Mexico
Worldwide, one in every three species of amphibian is endangered, 39 species have gone extinct in the last 500 years and another 130 species are suspected to have gone extinct in recent decades. Of the amphibians, salamanders have the highest portion of their species in one of the risk categories, even higher than the frogs. To date there have been few studies that have used recent field data to examine the status of populations of endangered salamanders. In this study we evaluate the current situation of two tiny salamanders, Parvimolge townsendi and Thorius pennatulus, both of which are distributed at intermediate elevations in the mountains of the northern Neotropics and are considered to be critically endangered; the first has been proposed as possibly extinct. By carrying out exhaustive surveys in both historical and potentially suitable sites for these two species, we evaluated their abundance and the characteristics of their habitats, and we estimated their potential geographic distribution. We visited 22 sites, investing 672 person-hours of sampling effort in the surveys, and found 201 P. townsendi salamanders in 11 sites and only 13 T. pennatulus salamanders in 5 sites. Both species were preferentially found in cloud forest fragments that were well conserved or only moderately transformed, and some of the salamanders were found in shade coffee plantations. The potential distribution area of both species is markedly fragmented and we estimate that it has decreased by more than 48%. The results of this study highlight the importance of carrying out exhaustive, systematic field surveys to obtain accurate information about the current situation of critically endangered species, and help us better understand the crisis that amphibians are facing worldwide
Caracterizaci?n de cobertura vegetal y propuesta de una red de conectividad ecol?gica en el Corredor Biol?gico Volc?nica Central-Talamanca, Costa Rica
Tesis (M. Sc) -- CATIE, Turrialba (Costa Rica), 2006En este trabajo se realiza un estudio sobre identificaci?n y caracterizaci?n de los tipos de bosques naturales para una propuesta de red de conectividad estructural ecol?gica en el Corredor Biol?gico Volc?nica Central-Talamanca. Estos bosques, fueron caracterizados y comparados en cuanto a variables como composici?n, estructura, riqueza y diversidad flor?stica. La distribuci?n de los tipos de bosques se lig? principalmente a cambios altitudinales. Fue posible as? elaborar un mapa preliminar de tipos de bosque en funci?n a la variable altitud. Con aplicaci?n SIG se desarrollaron cinco escenarios de redes de conectividad estructural ecol?gica, tomando en cuenta las rutas de conexi?n m?s corta. Cada una de estas trayectorias muestra similaridades en el recorrido de las redes, en donde se identificaron nueve zonas prioritarias para la conectividad en el CBVCT. In this research, a study on the identification and characterization of natural forest types was carried out for a proposal of an ecological structure connectivity network in the Volc?nica Central-Talamanca Biological Corridor (VCTBC). These forests were characterized and compared according to variables such as composition, structure, richness, and floristic diversity. the distribution of forest types is related principally to altitudinal changes. It was possible to create a preliminary map of forest types as a function of the altitude variable. with the application of a GIS, five ecological structure connectivity network scenarios were developed taking into account the shortest connectivity routes. Each of these routes shows similarities in the network where nine priority zones were identified for connectivity in the VCTBC
Proyecto de expansión para candybuncho a travez del metodo de franquicia
EL SISTEMA DE FRANQUICIA ES DE COOPERACION MUTUA, UNO DE ELLOS ES QUE SI NO SE MANEJAN BIEN LAS VARIABLES QUE IMPLICA UNA FRANQUICIA, EL NEGOCIO TIENE EL RIESGO DE DETERIORAR SU MARCA, SON LOS INCOVENIENTES,
LAS VENTAJAS DE LA FRANQUICIA ES LA EXPANSION CON DINERO DE OTRA PERSONA