Patrones de abundancia de los estadios tempranos de la sardina del Pacífico (Sardinops sagax) durante un periodo de enfriamiento en una laguna costera al sur de la corriente de California

Abundance patterns of eggs and larvae of the Pacific sardine, Sardinops sagax (Jenyns, 1842), in Bahía Magdalena, Baja California Sur, were analysed during a cooling period south of the California Current from 2005 to 2009. The thermohaline characteristics and zooplankton abundance were good descriptors of the potential spawning habitat. Individual quotient analyses showed a predominance of eggs and larvae within a SST range of 16 to 18°C, at low salinities (33.9-34.1) and at low density gradient variability (0.009-0.029), associated with deeper waters (25-40 m) near the main entrance, where the transparency was intermediate (6-8 m) and zooplankton abundance was relatively high ( > 316 ml/1000 m3). Increments within different class intervals meant that neither dissolved inorganic nitrogen (DIN), phosphates nor chlorophyll a predominated. The large interannual fluctuations in sardine spawning activity and preferential temperatures observed in historical and recent data suggest that two sardine stocks spawn in Bahia Magdalena: one stock spawned in the period 1981-1989 and one stock spawned in the period 1997-2009. The influence of cooling and warming periods as additional components of the regional environmental framework is analysed and discussed.Los patrones de abundancia de huevos y larvas de la sardina del Pacífico, Sardinops sagax, en Bahía Magdalena, Baja California Sur, fueron analizados durante un periodo de enfriamiento al sur de la Corriente de California de 2005 a 2009. La combinación de las características termohalinas y abundancia del zooplancton fueron buenos indicadores del hábitat potencial del desove. El análisis individual de cocientes mostró una predominancia de huevos y larvas en el intervalo de temperatura superficial del mar entre 16 y 18°C, a baja salinidad (33.9-34.1), y valores bajos de la diferencia del gradiente de densidad (0.009-0.029) asociados a las aguas profundas (25-40 m) cercanas a la entrada principal, donde la profundidad de transparencia fue intermedia (6-8 m), y la abundancia del zooplancton fue relativamente alta ( > 316 ml/1000 m3). El Nitrógeno Inorgánico Disuelto (DIN), fosfatos y clorofila a no revelan una clara predominancia, debido a incrementos en diferentes intervalos de clases. La amplia fluctuación interanual de la actividad reproductiva de la sardina y temperaturas preferenciales observadas en datos históricos y recientes sugiere la reproducción de dos poblaciones en Bahía Magdalena (1981-1989 y 1997-2009). La influencia de los periodos de enfriamiento y calentamiento como complemento de marco ambiental regional es analizada y discutida

Chitosan and Xyloglucan-Based Hydrogels: An Overview of Synthetic and Functional Utility

The development of new strategies for wound healing has resulted in the design of biomedical devices using polymers of natural origin. Hydrogels are biomaterials formed by three-dimensional polymeric networks that can retain large amounts of water or biological fluids, and smooth texture similar to living tissue. Chitosan is a linear polysaccharide, (1-4)-2-amino-2deoxy-ß-D-glucan, which has desirable features such as biocompatibility, non-toxicity, hemostasis and antibacterial character. Xyloglucans have different applications in tissue engineering for their physicochemical properties, biocompatibility and control of cell expansion. Hydrogels had been made of homogeneous mixtures prepared of chitosan and purified xyloglucan, followed by a freeze-drying process to develop a flexible and porous structure. Additionally, their mechanical properties such as porosity, solubility, biodegradation, and the antibacterial activity of the hydrogels are studied. The results suggest that the incorporation of xyloglucan favors the characteristics from chitosan-based hydrogels, providing a promising alternative for application in biomaterials with antimicrobial activity

Pesticide Exposure Alters Follicle-Stimulating Hormone Levels in Mexican Agricultural Workers

Organophosphorous pesticides (OPs) are suspected of altering reproductive function by reducing brain acetylcholinesterase activity and monoamine levels, thus impairing hypothalamic and/or pituitary endocrine functions and gonadal processes. Our objective was to evaluate in a longitudinal study the association between OP exposure and serum levels of pituitary and sex hormones. Urinary OP metabolite levels were measured by gas–liquid chromatography, and serum pituitary and sex hormone levels by enzymatic immunoassay and radioimmunoassay in 64 men. A total of 147 urine and blood samples were analyzed for each parameter. More than 80% of the participants had at least one OP metabolite in their urine samples. The most frequent metabolite found was diethylthiophosphate (DETP; 55%), followed by diethylphosphate (DEP; 46%), dimethylthiophosphate (DMTP; 32%), and dimethyldithiophosphate (DMDTP; 31%). However, the metabolites detected at higher concentrations were DMTP, DEP, DMDTP, and dimethylphosphate. There was a high proportion of individuals with follicle-stimulating hormone (FSH) concentrations outside the range of normality (48%). The average FSH serum levels were higher during the heavy pesticide spraying season. However, a multivariate analysis of data collected in all periods showed that serum FSH levels were negatively associated with urinary concentrations of both DMTP and DMDTP, whereas luteinizing hormone (LH) was negatively associated with DMTP. We observed no significant associations between estradiol or testosterone serum levels with OP metabolites. The hormonal disruption in agricultural workers presented here, together with results from experimental animal studies, suggests that OP exposure disrupts the hypothalamic–pituitary endocrine function and also indicates that FSH and LH are the hormones most affected

La agricultura periurbana multifuncional y sus aportaciones hacia la sustentabilidad regional en la Zona Metropolitana de Guadalajara, Jalisco, México

Un modelo de desarrollo basado en relaciones asimétricas y desequilibradas entre la ciudad y el campo, y entre la sociedad y sus ecosistemas, ha dado como resultado que en la Zona Metropolitana de Guadalajara (ZMG), en Jalisco, México, se generen conflictos ambientales en un entorno de creciente insustentabilidad regional. Algunas expresiones de esta situación se manifiestan en las áreas periurbanas y rurales con el avance descontrolado de la urbanización, la disminución de la superficie agropecuaria, la pérdida de vegetación y agrodiversidad, la deforestación, el agotamiento de los suelos, la disminución y contaminación del agua, la sanidad de los alimentos, las afectaciones a la salud pública y el deterioro del nivel de vida de sus habitantes. La importancia poblacional, económica y política de esta región y el aumento de los conflictos ambientales, demandan a los actores sociales e institucionales, la construcción de alternativas hacia la sustentabilidad regional, y en ellas juegan un papel fundamental la múltiples funciones que desempeña la agricultura periurbana o agricultura de proximidad. En este capítulo se presentan reflexiones y avances del proyecto de investigación e intervención “Agua, agrodiversidad y medio ambiente en la región Guadalajara-Chapala-Santiago” que a partir de una perspectiva de complejidad, ubicada en las ciencias de la sustentabilidad, ha realizado investigación interdisciplinaria en torno a tres procesos relevantes que generan conflictos ambientales en la región: a) uso y manejo del agua, b) relaciones ciudad campo, y c) gestión pública y social. El trabajo de intervención se ha orientado a la vinculación entre grupos y redes, a la formación campesino a campesino, al dialogo de saberes y al impulso de procesos sociales y organizativos, como parte del acompañamiento universitario a los actores locales en la construcción y fortalecimiento de sus alternativas hacia la sustentabilidad regional.ITESO, A.C

Comparación de la percepción social en playas recreativas arenosas de dos bahías localizadas en el Pacífico Mexicano

En el presente trabajo se desarrollaron dos formatos de encuesta, para incorporar la percepción de los usuarios a la evaluación de la calidad de las playas (Cervantes, 2006 y Silva-Iñiguez, 2006); ambos basados en un modelo cuantitativo para revelar la percepción social de las playas localizadas en la bahía de Santiago, Manzanillo, Col (MZO) y en Acapulco, Gro (ACA). Se aplicaron un total de 790 encuestas (ACA: 390 y MZO: 400), que permitieron conocer el perfil de los usuarios, sus hábitos de recreación y sus opiniones sobre las condiciones biofísicas y de infraestructura de cada playa. En ambas playas la mayoría prefirieron asistir acompañados por sus familias; las principales actividades recreativas fueron nadar, descansar, comer y beber. En general las demandas en ambos sitios coincidieron con incrementar el número de botes de basura, la frecuencia en el servicio de recolección y limpieza, baños y regaderas. Las razones por la que los usuarios seleccionaron la playa a visitar fueron la seguridad y vigilancia, así como las características biofísicas de la misma. La incorporación de esta información a modelos y/o esquemas de evaluación y gestión de playa (a través de índices ambientales) permitió realizar la valoración integral de la playa.In this paper it was developed two survey formats, to include the perception of users on the assessment of the quality of the beaches (Cervantes, 2006 and Silva-Iñiguez, 2006), both based on a quantitative model to reveal the social perception of the beaches on Santiago Bay, Manzanillo, Col (MZO) and Acapulco, Guerrero (ACA). We did a total of 790 surveys (ACA: 390 and MZO: 400), which allowed the user profile, recreation habits and their views on the biophysical and infrastructure of each beach. In both beaches, most people, attended with their families, the main recreational activities were swimming, resting, eating and drinking. In general the demands on both sites agreed to increase the number of waste baskets, the frequency of collection service and cleaning bathrooms and showers. The reasons why the users selected to visit the beach were the safety and security, as well as the biophysical characteristics of the same. Incorporating this information to models and / or evaluation schemes and beach management (through environmental ratings) allowed the comprehensive assessment of the beach

Scalar-field Pressure in Induced Gravity with Higgs Potential and Dark Matter

A model of induced gravity with a Higgs potential is investigated in detail in view of the pressure components related to the scalar-field excitations. The physical consequences emerging as an artifact due to the presence of these pressure terms are analysed in terms of the constraints parting from energy density, solar-relativistic effects and galactic dynamics along with the dark matter halos.Comment: 26 pages, 3 figures, Minor revision, Published in JHE

Identification of Phytoplankton Blooms under the Index of Inherent Optical Properties (IOP Index) in Optically Complex Waters

[EN] Phytoplankton blooms are sporadic events in time and are isolated in space. This complex phenomenon is produced by a variety of both natural and anthropogenic causes. Early detection of this phenomenon, as well as the classification of a water body under conditions of bloom or non-bloom, remains an unresolved problem. This research proposes the use of Inherent Optical Properties (IOPs) in optically complex waters to detect the bloom or non-bloom state of the phytoplankton community. An IOP index is calculated from the absorption coefficients of the colored dissolved organic matter (CDOM), the phytoplankton (phy) and the detritus (d), using the wavelength (lambda) 443 nm. The effectiveness of this index is tested in five bloom events in different places and with different characteristics from Mexican seas: 1. Dzilam (Caribbean Sea, Atlantic Ocean), a diatom bloom (Rhizosolenia hebetata); 2. Holbox (Caribbean Sea, Atlantic Ocean), a mixed bloom of dinoflagellates (Scrippsiella sp.) and diatoms (Chaetoceros sp.); 3. Campeche Bay in the Gulf of Mexico (Atlantic Ocean), a bloom of dinoflagellates (Karenia brevis); 4. Upper Gulf of California (UGC) (Pacific Ocean), a diatom bloom (Coscinodiscus and Pseudo-nitzschia) and 5. Todos Santos Bay, Ensenada (Pacific Ocean), a dinoflagellate bloom (Lingulodinium polyedrum). The diversity of sites show that the IOP index is a suitable method to determine the phytoplankton bloom conditions.CONACYT supported this research with a doctorate scholarship to Jesús A. Aguilar-Maldonado, with the announcement number 251025 in 2015. María-Teresa Sebastiá-Frasquet was a beneficiary of the BEST/2017/217 grant, supported by the Valencian Conselleria d Educació, Investigació, Cultura i Esport (Spain) during her stay at the Universidad Autónoma de Baja California (Mexico). 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Estuarine, Coastal and Shelf Science, 69(3-4), 459-470. doi:10.1016/j.ecss.2006.05.019Hernández-Terrones, L., Rebolledo-Vieyra, M., Merino-Ibarra, M., Soto, M., Le-Cossec, A., & Monroy-Ríos, E. (2010). Groundwater Pollution in a Karstic Region (NE Yucatan): Baseline Nutrient Content and Flux to Coastal Ecosystems. Water, Air, & Soil Pollution, 218(1-4), 517-528. doi:10.1007/s11270-010-0664-xMoore, Y. H., Stoessell, R. K., & Easley, D. H. (1992). Fresh-Water/Sea-Water Relationship Within a Ground-Water Flow System, Northeastern Coast of the Yucatan Peninsula. Ground Water, 30(3), 343-350. doi:10.1111/j.1745-6584.1992.tb02002.xBeddows, P. A., Smart, P. L., Whitaker, F. F., & Smith, S. L. (2007). Decoupled fresh–saline groundwater circulation of a coastal carbonate aquifer: Spatial patterns of temperature and specific electrical conductivity. Journal of Hydrology, 346(1-2), 18-32. doi:10.1016/j.jhydrol.2007.08.013Hernández-Terrones, L. M., Null, K. A., Ortega-Camacho, D., & Paytan, A. 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Environmental Development, 22, 120-128. doi:10.1016/j.envdev.2016.10.007Liefer, J. D., Robertson, A., MacIntyre, H. L., Smith, W. L., & Dorsey, C. P. (2013). Characterization of a toxic Pseudo-nitzschia spp. bloom in the Northern Gulf of Mexico associated with domoic acid accumulation in fish. Harmful Algae, 26, 20-32. doi:10.1016/j.hal.2013.03.002Schnetzer, A., Miller, P. E., Schaffner, R. A., Stauffer, B. A., Jones, B. H., Weisberg, S. B., … Caron, D. A. (2007). Blooms of Pseudo-nitzschia and domoic acid in the San Pedro Channel and Los Angeles harbor areas of the Southern California Bight, 2003–2004. Harmful Algae, 6(3), 372-387. doi:10.1016/j.hal.2006.11.004Peña Manjarrez, J. (2009). Environmental factors influencing the variability of Lingulodinium polyedrum and Scrippsiella trochoidea (Dinophyceae) cyst production. Ciencias Marinas, 35(1), 1-14. doi:10.7773/cm.v35i1.1406Ruiz-de la Torre, M. C., Maske, H., Ochoa, J., & Almeda-Jauregui, Cã©. O. (2013). 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Geographic factors associated with poorer outcomes in patients diagnosed with covid-19 in primary health care

Background: The prognosis of older age COVID-19 patients with comorbidities is associated with a more severe course and higher fatality rates but no analysis has yet included factors related to the geographical area/municipality in which the affected patients live, so the objective of this study was to analyse the prognosis of patients with COVID-19 in terms of sex, age, comorbidi-ties, and geographic variables. Methods: A retrospective cohort of 6286 patients diagnosed with COVID-19 was analysed, considering demographic data, previous comorbidities and geographic variables. The main study variables were hospital admission, intensive care unit (ICU) admission and death due to worsening symptoms; and the secondary variables were sex, age, comorbidities and geographic variables (size of the area of residence, distance to the hospital and the driving time to the hospital). A comparison analysis and a multivariate Cox model were performed. Results: The multivariate Cox model showed that women had a better prognosis in any type of analysed prog-nosis. Most of the comorbidities studied were related to a poorer prognosis except for dementia, which is related to lower admissions and higher mortality. Suburban areas were associated with greater mortality and with less hospital or ICU admission. Distance to the hospital was also associated with hospital admission. Conclusions: Factors such as type of municipality and distance to hospital act as social health determinants. This fact must be taken account in order to stablish specifics prevention measures and treatment protocols