El estado actual del estudio de florecimientos algales nocivos en México

This review presents an analysis of the state of knowledge of harmful algae studies in the marine environment in Mexico, in order to evaluate how we can optimize the available resources to study these events, identify unattended issues, and propose improvements in monitoring and/or research programs that could help to further understand the complexity of HAB in our coasts. An exhaustive bibliographic revision, from 1940 to 2011, was done consulting specialized data analyses, conference meetings, and specialized books and manuals. The number of researchers and institutions involved in HAB (harmful algal blooms) studies has increased significantly during the last decades, which is reflected in the number and quality of publications. However most of the existing HAB reports are based on sporadic sampling and short-term research programs. Monitoring programs and research activities have been focused in only a few HAB species; many toxic and harmful microalgal species have not been considered. To date, there is no laboratory with the capacity and techniques to analyze all the phycotoxins detected in Mexican coasts. Also, many research areas have not been attended adequately in Mexico such as cyst studies, allelophaty, exotic species, effect of climate change, use of molecular tools and teledetection, socioeconomic analyses, and mitigation strategies among others. This review shows that there has been a significantly improvement in the study of HAB in Mexico. However the studies are still addressed under an individual and disperse way and lack coordination. Greater achievements would be obtained if we concentrate the efforts of researchers and institutions were coordinated in order to optimize the available resources for HAB studies.Esta revisión da a conocer el estado de conocimiento de los estudios de Florecimientos Algales Nocivos (FAN) en el ámbito marino en México, con el objeto de evaluar la manera de optimizar los recursos destinados para el estudio de FAN en nuestro país, identificando líneas no abordadas y proponiendo mejoras en las actividades de monitoreo y de investigación que puedan aumentar nuestro conocimiento sobre la complejidad de FAN en nuestras costas. Se realizó una búsqueda bibliográfica de 1940 a 2011 consultando bases de datos, reuniones académicas y libros especializados. El número de investigadores e instituciones involucrados con el estudio de FAN se ha incrementado significativamente en las últimas décadas, lo cual se ve reflejado en el número y calidad de las publicaciones. Sin embargo, la mayoría de los programas y actividades de investigación están basados en muestreos puntuales y programas de investigación a corto plazo, enfocándose a pocas especies de FAN. Actualmente, varias líneas de investigación relacionadas con los FAN se han abordado pobremente o no se han considerado como son los estudios sobre quistes, alelopatía, transportación de especies por aguas de lastre, efecto del cambio climático, utilización de imágenes de satélite, uso de herramientas moleculares, análisis socioeconómicos y estrategias de mitigación, entre otros. Este análisis muestra que ha habido un avance significativo en el estudio de FAN en México, si bien la manera de abordar su estudio ha sido individualizada y dispersa. Se obtendría un mayor avance si se coordinaran los esfuerzos entre los diversos investigadores e instituciones para optimizar los recursos disponibles para el estudio de los FAN

Confianza y redes sociales en productores de hortalizas en San Luis Potosí, México

In this study, there were two objectives: a) analyzing the social networks of vegetable producers in the middle zone of San Luis Potosí, México, in order to determine their organization; and b) establishing the importance that trust has for business relations such as loaning money, asking for money or setting up a society. Surveys were applied to 35 producers, who referenced 170 names that were later concentrated into 39 producers. With the field information, symmetrical matrices were built to schematize the network structure, and three logistic regression models were formulated to establish the probability of intention for action based on trust. The results show the importance that proximity between actors has. It is concluded that different levels of trust explain the disposition to lending money, setting up a society and, to a lesser degree, asking for money on loan.En la presente investigación se tuvieron dos objetivos: a) analizar las redes sociales de los productores de hortalizas de la zona media de San Luis Potosí, México, a fin de determinar su organización; y b) establecer la importancia que tiene la confianza para las relaciones de negocios como prestar dinero, pedir dinero o hacer una sociedad. Se encuestó a 35 productores, que referenciaron 170 nombres que posteriormente se concentraron en 39 productores. Con la información de campo se construyeron matrices simétricas para esquematizar la estructura de la red y se formularon tres modelos de regresión logística para establecer la probabilidad de la intención de acción basada en la confianza. Los resultados muestran la importancia que tiene la proximidad entre actores. Se concluye que diferentes niveles de confianza explican la disposición a prestar dinero, hacer una sociedad y, en menor medida, a pedir dinero prestado

Toxinas paralizantes en moluscos bivalvos durante una proliferación de Gymnodinium catenatum Graham en la Bahía de La Paz, México

From February to March 2007 a harmful algae bloom of Gymnodinium catenatum Graham ocurred in Bahía de La Paz, Mexico, with cell densities from 6 x 105 to 2,39 x 106 cells L-1. During this event the toxin concentration and toxin profile of paralytic shellfish toxins in mollusks (Pinna rugosa, Modiolus capax, Megapitaria squalida, Periglypta multicostata, Dosinia ponderosa, and Megapitaria aurantiaca), and in phytoplankton samples were determined. Some physicochemical data were obtained. The average values of the surface temperature and dissolved oxygen were 20.9 ± 0.7 °C and 6.9 ± 0.3 mg L-1. The average concentrations of nitrites, nitrates, ammonium, phosphates, and silicates were 0.22 ± 0.05, 1.04 ± 0.33, 0.89 ± 0.88, 0.81 ± 0.76, and 8.85 ± 1.60 µM, respectively. The concentration of paralytic shellfish toxins in the net phytoplankton samples varied from 4.32 to 79.60 ng saxitoxin equivalents filter-1, identifying 8 toxins, the most abundant being C1 and C2. The highest toxin concentration found in mollusks were 31.14, 37.74, and 25.89 µg STXeq 100 g-1 in M. capax, P. rugosa, and M. aurantiaca, respectively. The variations in the paralytic toxin profile in the different mollusks species are given.De febrero a marzo de 2007, se presentó una proliferación de Gymnodinium catenatum Graham en la Bahía de La Paz (México), con densidades de 6 x 105 a 2,39 x 106 cél. L-1. Durante este evento se determinó la concentración y el perfil de toxinas paralizantes en moluscos bivalvos (Pinna rugosa, Modiolus capax, Megapitaria squalida, Periglypta multicostata, Dosinia ponderosa y Megapitaria aurantiaca) y en muestras de fitoplancton. También se obtuvieron algunos parámetros físicos y químicos. Los valores promedios de la temperatura superficial y del oxígeno disuelto fueron de 20.9 ± 0.7 °C y 6.9 ± 0.3 mg L-1, respectivamente. Las concentraciones promedios de nitritos, nitratos, amonio, fosfatos y silicatos fueron de 0.22 ± 0.05, 1.04 ± 0.33, 0.89 ± 0.88, 0.81 ± 0.76 y 8.85 ± 1.60 µM, respectivamente. El contenido de toxinas paralizantes en las muestras de arrastres de red variaron de 4.32 a 79.60 ng saxitoxina equivalente filtro-1, identificándose 8 toxinas, siendo la C1 y C2 las dominantes. Las máximas concentraciones de toxinas paralizantes en los moluscos fueron de 31.14, 37.74 y 25.89 µg STXeq. 100 g-1 en M. capax, P. rugosa y M. aurantiaca, respectivamente. Se dan a conocer las variaciones en el perfil de toxinas paralizantes en las diversas especies de moluscos

Paralytic Toxin Producing Dinoflagellates in Latin America: Ecology and Physiology

In this review we summarize the current state of knowledge regarding taxonomy, bloom dynamics, toxicity, autoecology, and trophic interactions, of saxitoxin producing dinoflagellates in this region. The dinoflagellates Gymnodinium catenatum, Pyrodinium bahamense and several species of Alexandrium are saxitoxin producers, and have been responsible of paralytic shellfish poisoning in different regions of Latin America, causing intoxications and important fisheries losses. The species distribution differ; most harmful algal blooms of G. catenatum are from the northern region, however this species has also been reported in central and southern regions. Blooms of P. bahamense are mostly reported in North and Central America, while blooms of Alexandrium species are more common in South America, however this genus is widely spread in Latin America. Species and regional differences are contrasted, with the aim to contribute to future guidelines for an international scientific approach for research and monitoring activities that are needed to increase our understanding of paralytic toxin producing dinoflagellates in this region

Ecological and Physiological Studies of Gymnodinium catenatum in the Mexican Pacific: A Review

This review presents a detailed analysis of the state of knowledge of studies done in Mexico related to the dinoflagellate Gymnodinium catenatum, a paralytic toxin producer. This species was first reported in the Gulf of California in 1939; since then most studies in Mexico have focused on local blooms and seasonal variations. G. catenatum is most abundant during March and April, usually associated with water temperatures between 18 and 25 ºC and an increase in nutrients. In vitro studies of G. catenatum strains from different bays along the Pacific coast of Mexico show that this species can grow in wide ranges of salinities, temperatures, and N:P ratios. Latitudinal differences are observed in the toxicity and toxin profile, but the presence of dcSTX, dcGTX2-3, C1, and C2 are usual components. A common characteristic of the toxin profile found in shellfish, when G. catenatum is present in the coastal environment, is the detection of dcGTX2-3, dcSTX, C1, and C2. Few bioassay studies have reported effects in mollusks and lethal effects in mice, and shrimp; however no adverse effects have been observed in the copepod Acartia clausi. Interestingly, genetic sequencing of D1-D2 LSU rDNA revealed that it differs only in one base pair, compared with strains from other regions

Elevated cholesterol in ATAD3 mutants is a compensatory mechanism that leads to membrane cholesterol aggregation

Aberrant cholesterol metabolism causes neurological disease and neurodegeneration, and mitochondria have been linked to perturbed cholesterol homeostasis via the study of pathological mutations in the ATAD3 gene cluster. However, whether the cholesterol changes were compensatory or contributory to the disorder was unclear, and the effects on cell membranes and the wider cell were also unknown. Using patient-derived cells, we show that cholesterol perturbation is a conserved feature of pathological ATAD3 variants that is accompanied by an expanded lysosome population containing membrane whorls characteristic of lysosomal storage diseases. Lysosomes are also more numerous in Drosophila neural progenitor cells expressing mutant Atad3, which exhibit abundant membrane-bound cholesterol aggregates, many of which co-localize with lysosomes. By subjecting the Drosophila Atad3 mutant to nutrient restriction and cholesterol supplementation, we show that the mutant displays heightened cholesterol dependence. Collectively, these findings suggest that elevated cholesterol enhances tolerance to pathological ATAD3 variants; however, this comes at the cost of inducing cholesterol aggregation in membranes, which lysosomal clearance only partly mitigates.M.M.O. was supported by a predoctoral fellowship from the University of the Basque Country (PIF18/317) and later partially supported by the Ikerbasque, Basque Foundation for Science IKUR strategy Neurodegenprot project. A.L. and U.F.P. were recipients of pre-doctoral fellowships from the Basque Government (PRE_2019_1_0184 and PRE_2018_1_0253). The study was supported by funding to I.J.H. from the Instituto de Salud Carlos III (PI17-00380; PI20/00096) and the Basque Government Department of Health (Osasun Saila, Eusko Jaurlaritzako) (grants 2021111070; 2022333050; 2018111043; 2018222031). A.Sp. receives support from Miriam Marks Senior Fellowship, Brain Research UK (202021-26), the Research Councils UK (MR/X002365/1) and the Lily Foundation. W.H.Y. is supported by the National Institute of Neurological Disorders and Stroke (5R01 NS121298-03) of the National Institutes of Health, Oklahoma Center for Adult Stem Cell Research (OCASCR) (221009 and 241006) and Presbyterian Health Foundation (4411-09-10-0).Peer reviewe

Role of age and comorbidities in mortality of patients with infective endocarditis

[Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. [Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. [Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. [Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe