15 research outputs found
Primera descripción del macho de Oonops nigromaculatus Mello-Leitão, 1944 (Araneae: Oonopidae) con la redescripción de la hembra y nuevos registros
The male of Oonops nigromaculatus Mello-Leitão 1944 is described for the first time and the female is redescribed from recently collected specimens. New records from Argentina and Uruguay are provided.Se describe por primera vez el macho de Oonops nigromaculatus Mello-Leitáo 1944, y la hembra se redescribe sobre la base de nuevos especímenes colectados recientemente. Se proveen nuevos registros de la Argentina y Uruguay.Centro de Estudios Parasitológicos y de Vectore
Primera descripción del macho de Oonops nigromaculatus Mello-Leitão, 1944 (Araneae: Oonopidae) con la redescripción de la hembra y nuevos registros
The male of Oonops nigromaculatus Mello-Leitão 1944 is described for the first time and the female is redescribed from recently collected specimens. New records from Argentina and Uruguay are provided.Se describe por primera vez el macho de Oonops nigromaculatus Mello-Leitáo 1944, y la hembra se redescribe sobre la base de nuevos especímenes colectados recientemente. Se proveen nuevos registros de la Argentina y Uruguay.Centro de Estudios Parasitológicos y de Vectore
Evidence of spatial clustering of childhood acute lymphoblastic leukemia cases in Greater Mexico City: report from the Mexican Inter-Institutional Group for the identification of the causes of childhood leukemia
BackgroundA heterogeneous geographic distribution of childhood acute lymphoblastic leukemia (ALL) cases has been described, possibly, related to the presence of different environmental factors. The aim of the present study was to explore the geographical distribution of childhood ALL cases in Greater Mexico City (GMC).MethodsA population-based case-control study was conducted. Children <18 years old, newly diagnosed with ALL and residents of GMC were included. Controls were patients without leukemia recruited from second-level public hospitals, frequency-matched by sex, age, and health institution with the cases. The residence address where the patients lived during the last year before diagnosis (cases) or the interview (controls) was used for geolocation. Kulldorff’s spatial scan statistic was used to detect spatial clusters (SCs). Relative risks (RR), associated p-value and number of cases included for each cluster were obtained.ResultsA total of 1054 cases with ALL were analyzed. Of these, 408 (38.7%) were distributed across eight SCs detected. A relative risk of 1.61 (p<0.0001) was observed for the main cluster. Similar results were noted for the remaining seven ones. Additionally, a proximity between SCs, electrical installations and petrochemical facilities was observed.ConclusionsThe identification of SCs in certain regions of GMC suggest the possible role of environmental factors in the etiology of childhood ALL
First description of the male of Oonops nigromaculatus Mello-Leitão, 1944 (Araneae: Oonopidae) with the redescription of the female and new records Primera descripción del macho de Oonops nigromaculatus Mello-Leitão, 1944 (Araneae: Oonopidae) con la redescripción de la hembra y nuevos registros
The male of Oonops nigromaculatus Mello-Leitão 1944 is described for the first time and the female is redescribed from recently collected specimens. New records from Argentina and Uruguay are provided.Se describe por primera vez el macho de Oonops nigromaculatus Mello-Leitão 1944, y la hembra se redescribe sobre la base de nuevos especímenes colectados recientemente. Se proveen nuevos registros de la Argentina y Uruguay
Procedimientos gráficos para obtener expresiones analíticas del estado estacionario y de las condiciones de estabilidad
Se presentan procedimientos gráficos para obtener
expresiones analíticas de la respuesta en estado
estacionario, y de las condiciones de estabilidad
de un sistema LTI MIMO modelado en Bond
Graph. Con técnicas de teoría de grafos se representa
la estructura de unión del sistema por un
grafo de Coates modificado, que permite determinar
el polinomio característico del sistema. Se
propone un grafo de estabilidad de Coates del
que se obtienen las condiciones de estabilidad.
Además, los valores de estado estacionario del sistema
en lazo abierto o en lazo cerrado se encuentran
directamente en la estructura de unión de su
modelo en Bond Graph en causalidad derivativa.
Graphical procedures are presented to get analytical
expressions of the stationary state response,
and of the stability conditions of a LTI MIMO
system modeled in Bond Graph. By using graph
theory techniques, the junction structure of the
system is represented by a modified Coates graph,
which allows determining the characteristic polynomial
of the system. A Coates stability graph is
proposed, from which the stability conditions are
obtained. Also, the stationary state values of the
system in open or closed loop are obtained directly
from the junction structure of its Bond
Graph model in derivative causality
Phytoplankton photosynthetic parameters off Baja California: A tool to estimate primary production with remote sensing data
Phytoplankton photosynthetic parameters (maximum light utilization coefficient, alpha*; maximum photosynthetic rate, P*m; maximum quantum yield, phi-max) off Baja California were estimated from samples collected at the 50% light level during winter, spring, summer, and autumn 1999. Chlorophyll concentration was also determined, and in situ experiments were conducted using the 14C method to determine primary production (PP) in the euphotic zone. The highest alpha* and phi-max values were found during the spring survey, mainly at the coastal areas, associated with diatom and dinoflagellate abundances and high chlorophyll concentrations. However, high P*m values were measured during autumn in both inshore and offshore areas due to the presence of smaller phytoplankton cells. The average profiles of the photosynthetic parameters (alpha*(z) and P*m(z)) in the water column were estimated for 2 regions. These parameters were used to estimate PP with semi-analytical models. Modeled PP was contrasted with in situ PP to validate our calculated photosynthetic parameters in the euphotic zone. In general, modeled PP values were similar to in situ values (94 mg C·m–2·h–1), with a high correlation coefficient (r = 0.85). Modeled PP for coastal waters in the northern and central regions was 1.5-fold greater than in situ estimates during spring. In conclusion, when used with remotely sensed phytoplankton pigment and surface irradiance data, the average profiles of alpha* and P*m(z) could be a useful tool to calculate PP in our study area
Effects of the interannual variability of water column stratification on phytoplankton production and biomass at the north zone off Baja California
The ocean off the Baja California Peninsula (Mexico) has been affected by interannual processes. Some of these processes have produced changes in oceanic circulation and the atmosphere, which have been reflected in the structure of the water column. Stratification, defined as the amount of energy needed to mix water throughout the water column, determines nutrient availability in the euphotic zone for phytoplankton growth. The aim of this study is to describe and relate the interannual variations of phytoplankton production and biomass with changes in the structure of the water column. To this end, we analyzed time series (1997–2016) for integrated Chlorophyll a, integrated primary production, pycnocline depth, mixed layer depth, and stratification indices along line 100 of the Investigaciones Mexicanas de la Corriente de California (IMECOCAL) program. The results showed 2 periods of high stratification and a decrease in phytoplankton production and biomass off Baja California, corresponding to the intrusion of subarctic water and El Niño 2015–2016. Finally, by using generalized additive models, we related 2 photosynthethic parameters-maximum photosynthetic rate and maximum light utilization coefficient-with water stratification. These relationships explained interannual variations in phytoplankton production in terms of water column stratification. The time series and the analysis reported here for IMECOCAL line 100 could be used to extrapolate the effects of interannual physical processes on phytoplankton in other zones off the Baja California peninsula
Evaluation of a Wetland Constructed with Typha domingensis Pers., for the Recovery of Contaminated Water from Hospital Effluents
The objective of this research project was to evaluate the implementation of a phytoremediation system for the effluents generated by the National Cancer Institute (INCAN), Central Department, Paraguay to contribute to the management of the liquid waste that it generates. The system consisted of a set of three pools, in which were made up of floating Typha domingensis Pers plants, at an approximate density of 10 plants per m2, all the roots formed a filter, which was in direct contact with the effluent. The effluent was of continuous flow; the flows of entry and exit were regulated according to the generation of liquid waste by INCAN. There were 5 measurements made with an interval of 7 days for each measurement, at a point of entry and exit of the effluent, to determine the system. The parameters evaluated were: BOD5, COD, NTK, PT, pH, temperature, conductivity, turbidity, dissolved oxygen and fecal coliforms. The results showed a considerable reduction of the pollutants generated for all the parameters evaluated, obtaining an efficiency of 67.9 to 92.4% in the evaluated parameters, indicating that it is very feasible to implement this type of systems for phytodepuration of liquid waste
El capital social para el turismo rural en Mata Clara y El Mirador, comunidades afrodescendientes de Veracruz
Social capital is the intangible ways of an individual functioning collectively, such as cooperation, trust, norms, social cohesion, and networks. These aspects can create and take advantage of other forms of capital such as physical, economic, and human. Consequently, social capital is essential to undertake a rural tourism project, and it is a priority to consider it an integral part of the project. To know their strengths and opportunities, the objective was to analyze the social capital oriented to rural tourism in two Afromexican communities in the Great Mountains region of Veracruz. A mixed investigation with discretionary non-probabilistic sampling was carried out on 31 people. The first part consisted of a survey to recognize the social capital in the communities of El Mirador in the municipality of Yanga, and Mata Clara in the municipality of Cuitlahuac. In the second part, in-depth interviews were conducted to build a heritage discourse to be used for tourist use. A certain degree of community fragmentation was identified, limiting opinions such as distrust of the government, insecurity, and identity. However, there is an attitude towards creating groups to carry out community tourism activities based on collaboration with work or economics based on trust in friends and family. In addition, a particular appropriation of some heritage elements is observed, the lack of knowledge of their history and the absence of background identity, as the main elements that limit the undertaking of community tourism projects.El capital social son las formas intangibles de un individuo que funciona colectivamente, como la cooperación, la confianza, las normas, la cohesión social y las redes; aspectos capaces de crear y aprovechar otras formas de capital como el físico, el económico y el humano; en consecuencia, el capital social es fundamental para emprender un proyecto de turismo rural y resulta prioritario estimarlo como parte integral del proyecto. El objetivo fue analizar el capital social orientado al turismo rural en dos comunidades afromexicanas de la región de las Grandes Montañas de Veracruz, para conocer sus fortalezas y oportunidades. Se realizó una investigación mixta con muestreo no probabilístico discrecional a 31 personas. La primera parte consistió de una encuesta para reconocer el capital social en las comunidades de El Mirador en el municipio de Yanga, y Mata Clara en el municipio de Cuitláhuac. En la segunda parte se realizaron entrevistas a profundidad para construir un discurso del patrimonio con miras a ser empleado para su aprovechamiento turístico. Se identifica cierto grado de fragmentación comunitaria, opiniones limitantes como la desconfianza al gobierno, inseguridad e identidad; sin embargo, existe una actitud a la creación de colectivos para realizar actividades turísticas comunitarias, fundadas en la colaboración con trabajo o económico con base en la confianza en amigos y familiares. Además, se observa cierta apropiación de algunos elementos patrimoniales, el desconocimiento de su historia y la ausencia de identidad de fondo, como los principales elementos que limitan el emprendimiento de proyectos turísticos comunitarios
Response of primary producers to the hydrographic variability in the southern region of the California Current System
The response of primary producers to seasonal and interannual variabilities in the hydrographic conditions observed between 1997 and 2012 is analyzed for the southern portion of the California Current System (CCS). The analysis uses the optimum rate of primary productivity (PP) normalized by units of chlorophyll (Chla) in the water column (PBopt) and Chla concentration. In situ PP estimations using the 14C method were obtained as part of the seasonal cruises conducted by the Investigaciones Mexicanas de la Corriente de California program. Supplementary data included sea surface temperature (SST) as measured by the AVHRR sensor from 1985–2009. We found the mean value of PBopt to be at 5.1 ± 3.3 mg C·(mg Chla)–1·h–1, with maximum ranges of 0.5 and 17.5 mg C·(mg Chla)–1·h–1. The relationship between PBopt and SST suggested a phytoplankton community change at around 19 ºC, which characterized the transitional nature of the southern portion of the CCS. SST data suggested, on the one hand, that on average the 19 ºC isotherm is located in the vicinity of Punta Eugenia and, on the other, that its spatial variability defined the alternating cool–warm conditions. At the seasonal scale, this isotherm showed a marked latitudinal displacement (from 24ºN to 32ºN), which was observed to be even out of this range during interannual events associated with El Niño/La Niña. Under both cool-warm hydrographic conditions, the phytoplanktonic community showed large PBopt rates (~6 mg C·(mg Chla)–1·h–1). At the interannual scale, changes were associated to changes in the abundance and composition of nano-microphytoplankton. Additionally, data suggested that high PP rates during warm periods could be attributed to an enhanced picoplankton contribution