Environmental Effects On Drosophila Brain Development And Learning

Brain development and behavior are sensitive to a variety of environmental influences including social interactions and physicochemical stressors. Sensory input in situ is a mosaic of both enrichment and stress, yet little is known about how multiple environmental factors interact to affect brain anatomical structures, circuits and cognitive function. In this study, we addressed these issues by testing the individual and combined effects of sub-adult thermal stress, larval density and early-adult living spatial enrichment on brain anatomy and olfactory associative learning in adult Drosophila melanogaster. In response to heat stress, the mushroom bodies (MBs) were the most volumetrically impaired among all of the brain structures, an effect highly correlated with reduced odor learning performance. However, MBs were not sensitive to either larval culture density or early-adult living conditions. Extreme larval crowding reduced the volume of the antennal lobes, optic lobes and central complex. Neither larval crowding nor early-adult spatial enrichment affected olfactory learning. These results illustrate that various brain structures react differently to environmental inputs, and that MB development and learning are highly sensitive to certain stressors (pre-adult hyperthermia) and resistant to others (larval crowding). © 2018. Published by The Company of Biologists Ltd

Distinct expressions of the BSR using various frequencies offshore Uruguay and its correspondence with the gas hydrate stability zone

At the Uruguayan continental margin, seismic evidence for the occurrence of gas hydrate has been identified based on the presence of BSRs in densely spaced 2D reflection seismic sections from different surveys. Mapping of BSRs based on 2D seismic data acquired in 2007 and 2008 suggested the presence of gas hydrates in areas that were not previously identified; hence hydrate occurrence offshore Uruguay is more widespread than previously thought. Recently ANCAP has digitized offshore seismic data acquired between 1970 and 1982. Being able to work on this data using interpretation software, and integrating results with the latest interpretations performed on the seismic collected in 2007 and 2008, the BSR extends over an area of approximately 25.000 km2. It is present in water depths greater than 500 m and has high continuity in Pelotas Basin but is more discontinuous at Punta del Este Basin and southern part of Oriental del Plata Basin. In offshore basins around the world the base of GHSZ can have different seismic expressions such as continuous, segmented, and high-relief BSRs depending on the stratigraphic, fluid and geothermal setting. Here, we present examples of the influence of the acquisition parameters on the acoustic expression of the BSR, comparing commercial seismic sections acquired for hydrocarbon exploration and high resolution seismic sections acquired during the R/V Meteor Cruise M49/2 in 2001 and R/V Meteor Cruise M78/3a (May - June 2009) using different sources and streamer system. For the different data sets the BSR presents differences regarding its continuity and amplitude strength. In high resolution seismic, enhanced amplitudes and phase reversals are observed for several reflectors while deep penetration seismic shows only one single continuous reflector. This comparison may help to visualize the complexity of the free gas, gas hydrate and stratigraphic system behind the BSR, which is usually masked on low-frequency deep penetration seismic data

Spatial association between a spider wasp and its host in fragmented dune habitats

Volume: 33Start Page: 222End Page: 22

Hybrid Statistical Data Mining Framework for Multi-Commodity Fixed Charge Network Flow Problem

This paper presents a new approach to analyze the network structure in multi-commodity fixed charge network flow problems (MCFCNF). This methodology uses historical data produced from repeatedly solving the traditional MCFCNF mathematical model as input for the machine-learning framework. Further, we reshape the problem as a binary classification problem and employ machine-learning algorithms to predict network structure. This predicted network structure is further used as an initial solution for our mathematical model. The quality of the initial solution generated is judged on the basis of predictive accuracy, feasibility and reduction in solving time

Le récit d'une recherche d'information sur internet comme élément constitutif d'une didactique du Web

Nous étudions un dispositif expérimental auprès d'étudiants en sciences de l'éducation dans la réalisation d'une recherche de situation didactique pour laquelle il leur était demandé de consigner par écrit le récit de la recherche. Les récits ainsi produits mettent en évidence la difficulté de mettre en mots une recherche d'information sur le Web, d'en retracer l'historique, d'expliquer les choix des requêtes et des outils. L'expérimentation a pour objectif de mettre à l'épreuve un exercice pratique de recherche d'information dans le cadre d'une pédagogie de l'enquête et vise à contribuer au repérage d'activités pédagogiques pour une didactique du We

Morphological structures relate to the location and extent of the seismogenic zone - bathymetric studies of the Sunda margin, Indonesia

Earthquake history shows that the Sunda subduction zone of the Indonesian margin produces great earthquakes offshore Sumatra, whereas earthquakes of comparable magnitude are lacking offshore Java and the Lesser Sunda islands. Morphological structures from multibeam bathymetric data across the forearc relate with the extent of the seismogenic zone (SZ). Off Java and the Lesser Sunda islands the Indo-Australian plate subducts almost normal underneath the oceanic plate of the Indonesian archipelago. Landward of the trench, the outer wedge of the slope break is ~50 km uniformly wide with uniform bathymetric gradients. The slope of the outer wedge is locally cut by one/two steeper ridges of ~5 km extent. The sharp slope break corresponds to the updip limit of the SZ, which is also associated with the seawardmost part of the outer arc high. Landward of the slope break we find narrow, uniform outer arc ridges. The landward termination of these ridges coincides with the downdip limit of the SZ. The intersection of the shallow upper plate mantle with the subduction thrust fault marks the downdip limit of the SZ beneath the forearc. Off Sumatra the Indo-Australian plate subducts obliquely underneath the continental part of the Indonesian Sunda margin. Landward of the trench, the outer wedge varies, being mostly ~70 km wide, in some areas narrowing to 50 km width. The lower slope bathymetric gradients are steep. The outer wedge slope is made up of several steeper ridges of ~5 km extent. The slope break is only locally sharp, and corresponds to the updip limit of the SZ. The outer arc ridges off Sumatra are, in comparison with the forearc structures off Java and the Lesser Sunda islands, wider and partly elevated above sea level forming the Mentawai forearc islands. The downdip limit of the SZ coincides with the intersection of a deeper upper plate mantle with the subduction thrust fault beneath the forearc. Sunda Strait marks a transition zone between the Sumatra and Java margins. Seafloor morphology enables the identification of the seismogenic zone (SZ) across the entire Sunda margin. The SZ is uniformly wide for the Sumatra margin and narrows off Sunda Strait. Sunda Strait is the transition between the Sumatra margin and the uniformly narrow extent of the SZ of the Java/Lesser Sunda margin. Comparing the Java and Lesser Sunda islands with the Sumatra margin we find the differences along the Sunda margin, especially the wider extent of the SZ off Sumatra, producing larger earthquakes, to result from the combination of various causes: The sediment income on the oceanic incoming plate and the subduction direction; we attribute a major role to the continental/oceanic upper plate nature of Sumatra/Java influencing the composition and deformation style along the forearc and subduction fault. Off Sumatra the SZ is up to more than twice as wide as off Java/Lesser Sunda islands, enlarging the unstable regime off Sumatra and thus the risk of sudden stress release in a great earthquake

Graduate Recital: Adriana Ladage

Kemp Recital HallMarch 29, 2014Saturday Afternoon4:30 p.m

The clinical and cellular basis of contact lens-related corneal infections

Microbial keratitis (MK) is the most visually devastating complication associated with contact lens wear. Pseudomonas aeruginosa (PA) is highly invasive in the corneal epithelium and is responsible for more than half of the reported cases of contact lens-related MK. To protect against Pseudomonas-mediated MK, the corneal epithelium has evolved overlapping defense mechanisms that function to protect the ocular surface from microbial invasion. Research has shown that contact lens wear disrupts these protective mechanisms through breakdown of normal homeostatic surface renewal as well as damaging the corneal surface, exposing underlying cell membrane receptors that bind and internalize PA through the formation of lipid rafts. Human clinical trials have shown that initial adherence of PA with resulting increased risk for microbial infection is mediated in part by contact lens oxygen transmissibility. Recently, chemical preserved multipurpose solutions (MPS) have been implicated in increasing PA adherence to corneal epithelial cells, in addition to inducing significant levels of toxic staining when used in conjunction with specific silicone hydrogel lenses. This review summarizes what is currently known about the relationship between contact lenses, the corneal epithelium, MPS, and infection

Climate-Related Variation in Spatial Memory and Hippocampal Morphology in Food-Caching Chickadees.

Harsh environments may lead to increased demands on memory in animals that rely on memory for survival. We previously showed that winter severity is associated with non-experience-based differences in memory and the hippocampus over a large continental scale in food-caching black-capped chickadees (Poecile atricapillus). However, large climatic differences also occur along steep elevational gradients in montane environments over a small geographic scale. Here we demonstrate for the first time that large differences in memory and the hippocampus exist over extremely short distances (10km) along the elevation gradient. We discovered that food-caching mountain chickadees (P. gambeli) from the highest elevations in the Sierra Nevada Mountains exhibited significantly better spatial memory associated with larger hippocampi with almost twice the number of hippocampal neurons compared to individuals only 600m lower in elevation. We found similarly large differences in hippocampal neurogenesis rates as indicated by the total number of immature neurons. Our study therefore suggests that climate-related environmental differences can produce dramatic differences in memory and the hippocampus in animals within close proximity on small spatial scales and that currently observed trends in global climate may have significant effects on cognition and the brain. Additionally, we attempted to integrate a new metric for enhanced spatial memory by looking specifically at the morphology of the neuron. While most comparative studies of cognition have focused on volumetric brain measurements it remains unclear whether neuron morphology, which appears to be directly linked to cognitive functions, may be responsive to differential selection on cognitive ability. We show that neuron soma size in the hippocampus, exhibits significant population variation associated with different environmental pressures on spatial memory related to differences in winter climate harshness in two species of food-caching chickadees. Comparing ten populations of black-capped chickadees and three populations of mountain chickadees along a gradient of winter climate harshness, we found that birds from harsher environments had significantly larger hippocampal neuron soma sizes. Finally, using chickadees from the two most divergent populations reared in a laboratory environment, we showed that these differences appear to be at least partly heritable as significant differences between these populations remained in birds sharing the same laboratory environment. At the same time, laboratory reared birds had significantly smaller neuron soma size compared to the wild-sampled birds, suggesting that at least some variation in neuron soma size may be due to environment-related plasticity. Our data suggests that environment-related selection on memory may generate differences in neuron morphology, which appear to be controlled by some heritable mechanisms and likely underlie population differences in spatial memory