Process to create simulated lunar agglutinate particles

A method of creating simulated agglutinate particles by applying a heat source sufficient to partially melt a raw material is provided. The raw material is preferably any lunar soil simulant, crushed mineral, mixture of crushed minerals, or similar material, and the heat source creates localized heating of the raw material

Color and pigment polymorphisms of northern leopard frogs on a prairie landscape

Variation allows populations to adapt to changing conditions. As human activities continue to alter environments and evolutionary processes, it becomes increasingly important to conserve standing genetic variation. Despite technical advances in population genetics, it is still useful to have inexpensive methods of detecting and monitoring genetic variation, particularly in traits that potentially influence fitness. In the Northern Leopard Frog, Lithobates pipiens (= Rana pipiens), genetically determined color (green [dominant: G] or brown [recessive: g]) and two pigment pattern polymorphisms (Burnsi/spotless [B] or spotted [b]; Kandiyohi/mottled [K] or non-mottled[k]) are hypothesized to have adaptive benefits. We assessed spatiotemporal patterns of these polymorphisms during two time periods in one of the largest remaining grasslands in North America. The frequency of the dominant green phenotype remained consistent from the early-to-late 2000s; however, we observed Kandiyohi phenotypes more frequently during 2001–2002 compared to 2009–2010. By contrast, we observed dominant Burnsi phenotypes more frequently in the latter time period. Although not statistically significant, we observed green phenotypes more frequently in areas with less water on the landscape and in locations closer to tree cover. Burnsi phenotypes were more common in wetlands that did not dry out and Kandiyohi phenotypes were more common in wetlands with aquatic vegetation, although not significantly. No pigment polymorphism was associated with body size. We found no indication of spatial structure, suggesting ample gene flow. The correlations were generally weak, but some were consistent with hypotheses of adaptive benefits. This genetically determined phenotypic variation could be important under changing climactic conditions or if land uses change

Nitrogen restricts future sub-Arctic treeline advance in an individual-based dynamic vegetation model

Arctic environmental change induces shifts in high-latitude plant community composition and stature with implications for Arctic carbon cycling and energy exchange. Two major components of change in high-latitude ecosystems are the advancement of trees into tundra and the increased abundance and size of shrubs. How future changes in key climatic and environmental drivers will affect distributions of major ecosystem types is an active area of research. Dynamic vegetation models (DVMs) offer a way to investigate multiple and interacting drivers of vegetation distribution and ecosystem function. We employed the LPJ-GUESS tree-individual-based DVM over the Torneträsk area, a sub-Arctic landscape in northern Sweden. Using a highly resolved climate dataset to downscale CMIP5 climate data from three global climate models and two 21st-century future scenarios (RCP2.6 and RCP8.5), we investigated future impacts of climate change on these ecosystems. We also performed model experiments where we factorially varied drivers (climate, nitrogen deposition and [CO2]) to disentangle the effects of each on ecosystem properties and functions. Our model predicted that treelines could advance by between 45 and 195 elevational metres by 2100, depending on the scenario. Temperature was a strong driver of vegetation change, with nitrogen availability identified as an important modulator of treeline advance. While increased CO2 fertilisation drove productivity increases, it did not result in range shifts of trees. Treeline advance was realistically simulated without any temperature dependence on growth, but biomass was overestimated. Our finding that nitrogen cycling could modulate treeline advance underlines the importance of representing plant-soil interactions in models to project future Arctic vegetation change

SEARCH: Spatially Explicit Animal Response to Composition of Habitat.

Complex decisions dramatically affect animal dispersal and space use. Dispersing individuals respond to a combination of fine-scale environmental stimuli and internal attributes. Individual-based modeling offers a valuable approach for the investigation of such interactions because it combines the heterogeneity of animal behaviors with spatial detail. Most individual-based models (IBMs), however, vastly oversimplify animal behavior and such behavioral minimalism diminishes the value of these models. We present program SEARCH (Spatially Explicit Animal Response to Composition of Habitat), a spatially explicit, individual-based, population model of animal dispersal through realistic landscapes. SEARCH uses values in Geographic Information System (GIS) maps to apply rules that animals follow during dispersal, thus allowing virtual animals to respond to fine-scale features of the landscape and maintain a detailed memory of areas sensed during movement. SEARCH also incorporates temporally dynamic landscapes so that the environment to which virtual animals respond can change during the course of a simulation. Animals in SEARCH are behaviorally dynamic and able to respond to stimuli based upon their individual experiences. Therefore, SEARCH is able to model behavioral traits of dispersing animals at fine scales and with many dynamic aspects. Such added complexity allows investigation of unique ecological questions. To illustrate SEARCH\u27s capabilities, we simulated case studies using three mammals. We examined the impact of seasonally variable food resources on the weight distribution of dispersing raccoons (Procyon lotor), the effect of temporally dynamic mortality pressure in combination with various levels of behavioral responsiveness in eastern chipmunks (Tamias striatus), and the impact of behavioral plasticity and home range selection on disperser mortality and weight change in virtual American martens (Martes americana). These simulations highlight the relevance of SEARCH for a variety of applications and illustrate benefits it can provide for conservation planning

Overexpression of Protein Kinase C βII Induces Colonic Hyperproliferation and Increased Sensitivity to Colon Carcinogenesis

Protein kinase C βII (PKC βII) has been implicated in proliferation of the intestinal epithelium. To investigate PKC βII function in vivo, we generated transgenic mice that overexpress PKC βII in the intestinal epithelium. Transgenic PKC βII mice exhibit hyperproliferation of the colonic epithelium and an increased susceptibility to azoxymethane-induced aberrant crypt foci, preneoplastic lesions in the colon. Furthermore, transgenic PKC βII mice exhibit elevated colonic β-catenin levels and decreased glycogen synthase kinase 3β activity, indicating that PKC βII stimulates the Wnt/adenomatous polyposis coli (APC)/β-catenin proliferative signaling pathway in vivo. These data demonstrate a direct role for PKC βII in colonic epithelial cell proliferation and colon carcinogenesis, possibly through activation of the APC/β-catenin signaling pathway

Receptors and Other Signaling Proteins Required for Serotonin Control of Locomotion in Caenorhabditis elegans

A better understanding of the molecular mechanisms of signaling by the neurotransmitter serotonin is required to assess the hypothesis that defects in serotonin signaling underlie depression in humans. Caenorhabditis elegans uses serotonin as a neurotransmitter to regulate locomotion, providing a genetic system to analyze serotonin signaling. From large-scale genetic screens we identified 36 mutants of C. elegans in which serotonin fails to have its normal effect of slowing locomotion, and we molecularly identified eight genes affected by 19 of the mutations. Two of the genes encode the serotonin-gated ion channel MOD-1 and the G-protein-coupled serotonin receptor SER-4. mod-1 is expressed in the neurons and muscles that directly control locomotion, while ser-4 is expressed in an almost entirely non-overlapping set of sensory and interneurons. The cells expressing the two receptors are largely not direct postsynaptic targets of serotonergic neurons. We analyzed animals lacking or overexpressing the receptors in various combinations using several assays for serotonin response. We found that the two receptors act in parallel to affect locomotion. Our results show that serotonin functions as an extrasynaptic signal that independently activates multiple receptors at a distance from its release sites and identify at least six additional proteins that appear to act with serotonin receptors to mediate serotonin response.National Institutes of Health (U.S.) (Grant GM24663

Performance of a fast, highly segmented electromagnetic calorimeter

We describe the energy, position, and angular resolutions of an electromagnetic calorimeter consisting of 56 layers of proportional wire and lead-filled tubes. The calorimeter was tested with two different electronic readout systems in a beam of electrons with energies ranging from 10 to 200 GeV.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29102/1/0000140.pd