414 research outputs found
Should Species Distribution Models Account for Spatial Autocorrelation? A Test of Model Projections Across Eight Millennia of Climate Change
Aim: The distributions of many organisms are spatially autocorrelated, but it is unclear whether including spatial terms in species distribution models (SDMs) improves projections of species distributions under climate change. We provide one of the first comparative evaluations of the ability of a purely spatial SDM, a purely non-spatial SDM and a SDM that combines spatial and environmental information to project species distributions across eight millennia of climate change. Location: Eastern North America. Methods: To distinguish between the importance of climatic versus spatial explanatory variables we fit three Bayesian SDMs to modern occurrence data for Fagus and Tsuga, two tree genera whose distributions can be reliably inferred from fossil pollen: a spatially varying intercept model, a non-spatial model with climatic variables and a spatially varying intercept plus climate model. Using palaeoclimate data with a high temporal resolution, we hindcasted the SDMs in 1000-year time steps for 8000 years, and compared model projections with palynological data for the same periods. Results: For both genera, spatial SDMs provided better fits to the calibration data, more accurate predictions of a hold-out validation dataset of modern trees and higher variance in current predictions and hindcasted projections than non-spatial SDMs. Performance of non-spatial and spatial SDMs according to the area under the receiver operating curve varied by genus. For both genera, false negative rates between non-spatial and spatial models were similar, but spatial models had lower false positive rates than non-spatial models. Main conclusions: The inclusion of computationally demanding spatial random effects in SDMs may be warranted when ecological or evolutionary processes prevent taxa from shifting their distributions or when the cost of false positives is high.Organismic and Evolutionary Biolog
SLC26A11 (KBAT) in Purkinje Cells Is Critical for Inhibitory Transmission and Contributes to Locomotor Coordination
Chloride homeostasis determines the impact of inhibitory synaptic transmission and thereby mediates the excitability of neurons. Even though cerebellar Purkinje cells (PCs) receive a pronounced inhibitory GABAergic input from stellate and basket cells, the role of chloride homeostasis in these neurons is largely unknown. Here we studied at both the cellular and systems physiological level the function of a recently discovered chloride channel, SLC26A11 or kidney brain anion transporter (KBAT), which is prominently expressed in PCs. Using perforated patch clamp recordings of PCs, we found that a lack of KBAT channel in PC-specific KBAT KO mice (L7-KBAT KOs) induces a negative shift in the reversal potential of chloride as reflected in the GABAA-receptor- evoked currents, indicating a decrease in intracellular chloride concentration. Surprisingly, both in vitro and in vivo PCs in L7-KBAT KOs showed a significantly increased action potential firing frequency of simple spikes, which correlated with impaired motor performance on the Erasmus Ladder. Our findings support an important role for SLC26A11 in moderating chloride homeostasis and neuronal activity in the cerebellum
SLC26A11 (KBAT) in Purkinje Cells Is Critical for Inhibitory Transmission and Contributes to Locomotor Coordination
Chloride homeostasis determines the impact of inhibitory synaptic transmission and thereby mediates the excitability of neurons. Even though cerebellar Purkinje cells (PCs) receive a pronounced inhibitory GABAergic input from stellate and basket cells, the role of chloride homeostasis in these neurons is largely unknown. Here we studied at both the cellular and systems physiological level the function of a recently discovered chloride channel, SLC26A11 or kidney brain anion transporter (KBAT), which is prominently expressed in PCs. Using perforated patch clamp recordings of PCs, we found that a lack of KBAT channel in PC-specific KBAT KO mice (L7-KBAT KOs) induces a negative shift in the reversal potential of chloride as reflected in the GABAA-receptor-evoked currents, indicating a decrease in intracellular chloride concentration. Surprisingly, both in vitro and in vivo PCs in L7-KBAT KOs showed a significantly increased action potential firing frequency of simple spikes, which correlated with impaired motor performance on the Erasmus Ladder. Our findings support an important role for SLC26A11 in moderating chloride homeostasis and neuronal activity in the cerebellum
The Implications of Substance Abuse Among Dental Professionals
According to literature, the rate of drug abuse and addiction is higher in dental providers than in the general population. This is because dental providers have greater access to prescription drugs as well as occupational stresses that put these individuals at risk. The stresses of education, work, patient’s needs, finances, and economic burdens can lead to self-neglect and heightened chances of drug use among dental professionals. Hence, these individuals are at a greater risk of developing a substance abuse problem. Dental professionals that abuse substances while working violate many legal, ethical, and clinical standards amended by the ADA and the Texas State Board. Under the Hippocratic Oath, it is the healthcare provider’s duty to treat patients to the best of their ability and not endanger themselves with any substances that could lead to malpractice within the office. Any report of substance abuse within the health community will be referred to the state board of dentistry or other authorities where they may suspend or revoke their license. There are many strategies that may aid dental health professionals in their recovery from substance abuse. Many times, states offer a diversion program that allows dental health professionals to recover from their addiction without losing their license. These programs have high recovery rates among dental professionals. Overall, further research should be done on the topic of substance abuse within the professional dental community since this issue could lead to the possibility of patient endangerment if those affected by abuse are not helped
Gender Violence in the University: The Role of Higher Education Institutions in its Prevention
Talking about gender-based violence and sexual harassment at the Ecuadorian university has been considered by many as an uncomfortable subject, and for some years it has been silenced. It is only recently that this situation has become an essential topic to investigate, so that currently several universities have struggled to explore through studies the problems of gender violence, discrimination and sexual harassment in the university context. In this sense, the present study has tried to develop a review of all the investigations that have been carried out to identify cases or situations of gender violence in universities at international, national and local level, as well as to determine the role of education institutions superior in the prevention and eradication of this problem.
Keywords: gender violence, sexual harassment, university.
Resumen
Hablar de violencia de género y acoso sexual en la universidad ecuatoriana ha sido considerado por muchos como un tema incómodo por lo que durante algunos años ha permanecido silenciado. No es sino hace poco que esta situación se ha vuelto una temática imprescindible de investigar, por lo que actualmente varias universidades se han esforzado en explorar a través de estudios los problemas de violencia de género, discriminación y acoso sexual en el contexto universitario. En este sentido, el presente estudio ha pretendido desarrollar una revisión de todas las investigaciones que se han realizado para identificar los casos o situaciones de violencia de género en universidades a nivel internacional, nacional y local, así como determinar el rol de las instituciones de educación superior en la prevención y erradicación de esta problemática.
Palabras clave: violencia de género, acoso sexual, universidad
Extracción acuosa y secado del mucílago de yausabara (Pavonia sepium A. St.-Hil)
The objective of this research work was to evaluate the aqueous extraction process for obtaining mucilage from yausabara (Pavonia sepium A. St.-Hil.), a mucilaginous plant found in various wet areas. The research arose from the need to offer alternatives to the agro-industrial sector. The aqueous extracts of the mucilage were obtained from peeled stems, both chopped and ground, using solid-liquid ratios of 1:4 and 1:6, over periods of 6, 12, and 24 hours. The viscosity, turbidity, and total solid content of these extracts were determined. An optimal extraction run was achieved (peeled and chopped stems with a solid-liquid ratio of 1:4 for 20.42 hours), resulting in a viscosity of 51.72 mPa·s, turbidity of 2600 NTU, and a total solid content of 0.87%. The mucilage was precipitated with ethanol from the aqueous extract, and the precipitate was then dried at 40 ºC in an oven for 3 days. The antioxidant capacity and total phenolic content of the obtained powder were determined using the Folin-Ciocalteu and FRAP methods, respectively. The powdered mucilage showed a total phenolic content of 0.0046 mg/g and an antioxidant capacity expressed as Fe2+, of 18.63 µM/g of powder, values that are low compared to those reported for plant-derived extracts.El objetivo del presente trabajo de investigación fue evaluar el proceso de extracción acuosa para la obtención del mucílago de yausaba (Pavonia sepium A. St.-Hil.), una planta mucilaginosa que se encuentra en distintos terrenos húmedos. La investigación surgió de la necesidad de ofrecer alternativas al sector agroindustrial. La obtención de los extractos acuosos del mucílago se realizó a partir de tallos pelados, tanto troceados como molidos, utilizando relaciones sólido-líquido de 1:4 y 1:6, durante períodos de 6, 12 y 24 horas. Se determinó la viscosidad, turbidez y contenido de sólidos totales de dichos extractos. Se obtuvo una corrida con óptimas condiciones de extracción (tallos pelados y troceados con una relación sólido-líquido de 1:4 durante 20,42 horas), que arrojó como resultado una viscosidad de 51,72, una turbidez de 2600 NTU y un contenido de sólidos totales de 0,87%. El mucílago se precipitó con etanol a partir del extracto acuoso, y luego se realizó el secado del precipitado a 40 ºC en estufa durante 3 días. Al polvo obtenido se le determinó su capacidad antioxidante y contenido de polifenoles totales mediante los métodos Folin-Ciocalteu y FRAP, respectivamente. El mucílago en polvo presentó un contenido de polifenoles totales de 0,0046 mg/g y una capacidad antioxidante expresada como Fe2+, de 18,63 µM/g de polvo, valores bajos en comparación con los reportados para extractos de origen vegetal
Natural Energy Bars With Protein Improvement From Animal Origin Foods
The energy bars provide the consumer with nutritional and organoleptic quality, as well as a prolonged shelf life without the need to modify the temperature for storage, however, they do not satisfy the nutritional requirements of high-quality proteins since they are usually made from cereals, which are low cost ingredients and great energy contribution. The objective of this study was to create an energetic and nutritious bar, without diminishing the technological quality of the commercial bars and that, due to their sensory characteristics, are easily included in the daily consumption of people who exercise and want to control their weight. A product was formulated with a greater contribution and protein quality, and with a functional dose of macronutrients. The product was prepared in compliance with the regulations of the Ecuadorian Institute for Standardization (INEN) and the Food Codex, the premixing and roasting of ingredients was controlled and finally food with animal protein source such as egg white and powdered milk was added. For the premix oat flakes, nuts such as nuts, almonds and hazelnuts, chia seeds and honey were used, then added egg white and powdered milk. The protein content it reached was 29.01% on a wet basis, a fat value of 23.10% and carbohydrates of 25.24% on 100 g of sample on a wet basis. The energy distribution of macronutrients was balanced, and the sensory evaluation showed good product acceptability.
Keywords: cereal bars, protein, immediate energy.
Resumen
Las barras energéticas proporcionan al consumidor calidad nutricional y organoléptica, así como una vida de anaquel prolongada sin necesidad de modificar la temperatura para su almacenamiento, sin embargo, no satisfacen los requerimientos nutricionales de proteínas de alta calidad ya que generalmente están elaboradas a base de cereales, que son ingredientes de bajo costo y gran aporte energético. El objetivo se este estudio fue crear una barra energética y nutritiva, sin disminuir la calidad tecnológica de las barras comerciales y que por sus características sensoriales sean fácilmente incluidas en el consumo diario de personas que se ejercitan y quieren controlar su peso. Se formuló un producto con un mayor aporte y calidad proteica, y con una dosis funcional de macronutrientes. El producto se elaboró cumpliendo las normativas del Instituto Ecuatoriano de Normalización (INEN) y del Codex alimentario, se controló la premezcla y tostado de ingredientes y finalmente se adicionó los alimentos con fuente proteica animal como la clara de huevo y leche en polvo. Para la premezcla se utilizaron hojuelas de avena, frutos secos como nueces, almendras y avellanas, semillas de chía y miel de abeja, luego se adicionó la clara de huevo y la leche en polvo. El contenido proteico que alcanzó fue de 29,01% en base húmeda, un valor en grasas de 23,10% y de carbohidratos de 25,24% de muestra en base húmeda. La distribución energética de macronutrientes fue equilibrada y la evaluación sensorial arrojó una buena aceptabilidad del producto.
Palabras claves: barras de cereales, proteína, energía inmediata
Reducing GBA2 activity ameliorates neuropathology in niemann-pick type C mice
The enzyme glucocerebrosidase (GBA) hydrolyses glucosylceramide (GlcCer) in lysosomes. Markedly reduced GBA activity is associated with severe manifestations of Gaucher disease including neurological involvement. Mutations in the GBA gene have recently also been identified as major genetic risk factor for Parkinsonism. Disturbed metabolism of GlcCer may therefore play a role in neuropathology. Besides lysosomal GBA, cells also contain a non-lysosomal glucosylceramidase (GBA2). Given that the two β-glucosidases share substrates, we speculated that over-activity of GBA2 during severe GBA impairment might influence neuropathology. This hypothesis was studied in Niemann-Pick type C (Npc1-/-) mice showing secondary deficiency in GBA in various tissues. Here we report that GBA2 activity is indeed increased in the brain of Npc1-/- mice. We found that GBA2 is particularly abundant in Purkinje cells (PCs), one of the most affected neuronal populations in NPC disease. Inhibiting GBA2 in Npc1-/- mice with a brain-permeable low nanomolar inhibitor significantly improved motor coordination and extended lifespan in the absence of correction in cholesterol and ganglioside abnormalities. This trend was recapitulated, although not to full extent, by introducing a genetic loss of GBA2 in Npc1-/- mice. Our findings point to GBA2 activity as therapeutic target in NPC
Hexavalent Chromium in Waters for Human Consumption and Irrigation in the Guano Canton
Introduction: Considering the geographical location and industrial activities of the county Guano, which lies on an aquifer that supply water for both consumption and crop irrigation, it is necessary to examine the levels of chromium (Cr) in its watershed and tributaries. Objective: To evaluate the amount of Cr existing in the surface waters of the Guano river basin and aquifer. Methods: Several samples of the river and aquifer were taken and the amount of Cr present was measured. Using Z-test, Cr levels found in the water were compared with those recommended as normal by the World Health Organization (WHO), national standards of the Texto Unificado de Legislación Secundaria de Medio Ambiente (TULSMA) and the Servicio Ecuatoriano de Normalización 1108 ( INEN 1108). Results: Relatively high Cr values were found when compared with those established by the WHO. However, they were normal when compared with TULSMA and INEN 1108. Conclusion: The levels of Cr found in the Guano river and the aquifer were higher than those recommended by the WHO. It is recommended to replicate our findings in order to corroborate the results and to take appropriate measures in order to reduce water contamination.
Keywords: chromium, water, Guano, Ecuador.
Resumen
Introducción: Considerando la ubicación geográfica y actividades industriales del cantón Guano el cual yace sobre un acuífero que sustenta las necesidades de agua tanto para consumo y riego de la población es necesario examinar los niveles de Cromo (Cr) en su vertiente como sus afluentes. Objetivo: Evaluar la cantidad de Cr existente en las aguas superficiales de la cuenca del río Guano y en pequeños ojos de agua provenientes del acuífero. Métodos: Se tomó varias muestras de agua del río y ojos de agua y se midió la cantidad de Cr presente. Por medio de la prueba Z se comparó los niveles de Cr con los recomendados como normales por la Organización Mundial de la Salud (OMS), normas nacionales del Texto Unificado de Legislación Secundaria de Medio Ambiente (TULSMA) y Servicio Ecuatoriano de Normalización 1108 (INEN 1108). Resultados: Se encontró valores relativamente altos de Cr al compararlos con los establecidos por la OMS. Sin embargo, estos se encontraron dentro de rangos normales al compararlos con TULSMA e INEN 1108. Conclusiones: Los niveles de Cr encontrados en el río Guano y ojos de agua del acuífero son superiores a los recomendados por la OMS. Se recomienda replicar los hallazgos para corroborar los resultados y tomar las medidas adecuadas para reducir la contaminación del agua.
Palabras clave: cromo, agua, Guano, Ecuador
Which Factors Determine Spatial Segregation in the South American Opossums (Didelphis aurita and D. albiventris)? An Ecological Niche Modelling and Geometric Morphometrics Approach
Didelphis albiventris and D. aurita are Neotropical marsupials that share a unique evolutionary history and both are largely distributed throughout South America, being primarily allopatric throughout their ranges. In the Araucaria moist forest of Southern Brazil these species are sympatric and they might potentially compete having similar ecology. For this reason, they are ideal biological models to address questions about ecological character displacement and how closely related species might share their geographic space. Little is known about how two morphologically similar species of marsupials may affect each other through competition, if by competitive exclusion and competitive release. We combined ecological niche modeling and geometric morphometrics to explore the possible effects of competition on their distributional ranges and skull morphology. Ecological niche modeling was used to predict their potential distribution and this method enabled us to identify a case of biotic exclusion where the habit generalist D. albiventris is excluded by the presence of the specialist D. aurita. The morphometric analyses show that a degree of shape discrimination occurs between the species, strengthened by allometric differences, which possibly allowed them to occupy marginally different feeding niches supplemented by behavioral shift in contact areas. Overlap in skull morphology is shown between sympatric and allopatric specimens and a significant, but weak, shift in shape occurs only in D. aurita in sympatric areas. This could be a residual evidence of a higher past competition between both species, when contact zones were possibly larger than today. Therefore, the specialist D. aurita acts a biotic barrier to D. albiventris when niche diversity is not available for coexistence. On the other hand, when there is niche diversification (e.g. habitat mosaic), both species are capable to coexist with a minimal competitive effect on the morphology of D. aurita
- …
