Testing the use of molluscs to infer climate with special reference to the late Cenozoic molluscs of the Meade Basin, southwest Kansas.

Twenty-six fossil assemblages of land and freshwater molluscs from the Pliocene to the present, were collected from locations near the town of Meade, Kansas, U.S.A. and were analyzed (along with the extant molluscan fauna of Meade County, Kansas) to look for changes in molluscan diversity through time. The fossil assemblages were analyzed for two reasons: I) to test the hypothesis that diversity (measured as taxonomic richness, dominance, turnover and habitat type) did not change through the five million years of this study (HOI); and 2) to test the hypothesis that there is no relationship between the taxonomic composition of a molluscan assemblage and the local climate (H02)\u27 The latter hypothesis was tested by re-examining prior molluscan paleoecological studies, by analyzing the molluscan assemblages collected for this study and through ordination analysis. The results of the first analysis clearly showed that the taxonomic structure of the assemblages changed through time (HOI was falsified), but the changes appeared to be random fluctuations. Richness ranged from 7 taxa (in assemblages AGO, FAL, RYA, SPA) to 30 (C03B) with r2 = 0.237. Dominance ranged from 1.40 (SPA) to 9.66 (RTA) with r2 = 0.113. The Habitat Ratio ranged from -0.43 (FAL) to 1.00 (X I E) with r2 = 0.029 and Turnover ranged from 0.17 (AGO, F AL) to 1.00 (RNT), when each assemblage was compared to RNT (r2 = 0.024). No discernable long-tern trend in taxonomic diversity or community composition was observed. The results of the second analysis indicate that molluscs, as a group, are not as useful as climate indicators as previously supposed. Today, both land and freshwater mollusc species are broadly geographically distributed and thus are found in a variety of locations with different local climates and vegetation. Previously, Miller (1975, 1976) grouped molluscan species with similar environmental tolerances into four units called Climate Groups and used them to infer the past climatic conditions of a region. However, only a weak climate signal was detected (ANOY A found significant differences among the Groups for minimum temperature [p \u3c 0.0001], maximum temperature [p \u3c 0.0001] and annual precipitation [p = 0.0082]), after the previous results were reanalyzed using the methods of this study. The fossil molluscan assemblages collected for this study displayed no climate signal (ANOY A found no significant differences among the assemblages for minimum temperature [p = 0.0714] or precipitation [p =0.691] but did find a difference in maximum temperature [p = 0.0207]. A subsequent Tukey-Kramer HSD test failed to find significant differences among assemblages). Finally, the results from ordination analysis of my data did not show a strong relationship between the climate variables used in this study (minimum and maximum temperatures, annual precipitation) and the current geographic distribution of molluscan taxa. One should proceed with caution if molluscs are to be used to interpret climate. The results of this study do not provide a strong endorsement for using molluscs as paleoclimate indicators. This finding is counter to the prevailing wisdom among paleontologists. More work needs to be done in the area of molluscan biogeography and physiology to see if the conclusions herein hold up and to better understand molluscan biology in general

Porcupine homolog is required for canonical Wnt signaling and gastrulation in mouse embryos

AbstractWnt signaling plays important roles in development and disease. The X-chromosomal Porcupine homolog gene (Porcn) encodes an evolutionary conserved member of the membrane bound O-acyl transferase (MBOAT) superfamily that has been shown to be required for the palmitoylation and secretion of Wnt3a, a mechanism that has been suggested to be conserved for all mammalian Wnt ligands. PORCN mutations in humans cause Focal Dermal Hypoplasia (FDH), a disorder causing developmental defects in heterozygous females and embryonic lethality in hemizygous males. In this study, Porcn mutant mouse embryonic stem (ES) cells were used to analyze the role of Porcn in mammalian embryonic development. In vitro, we show an exclusive requirement for Porcn in Wnt secreting cells and further, that any of the four Porcn isoforms is sufficient to allow for the secretion of functional Wnt3a. Embryos generated by aggregation of Porcn mutant ES cells with wildtype embryos fail to complete gastrulation in vivo, but remain in an epiblast-like state, similar to Wnt3 and Gpr177/Wls mutants. Consistent with this phenotype, in vitro differentiated mutant ES cells fail to generate endoderm and mesoderm derivatives. Taken together, these data confirm the importance of Porcn for Wnt secretion and gastrulation and suggest that disruption of early development underlies the male lethality of human PORCN mutants

Heat Matters: The Missing Link in REPowerEU:2030 District Heating Deployment for a long-term Fossil-free Future

This report employs a Smart Energy System approach to redesign Europe's energy infrastructure, emphasizing the expansion of district heating as a strategic move to eliminate gas-based heating in European buildings. It introduces a novel quantification of waste heat potentials and integrates it with analyses of future potential district heating market shares in Europe. Both in a REPowerEU 2030 and long-term decarbonization temporal perspective. Additionally, it provides a quantification of the investment required in district heating infrastructure to achieve substantial reductions in the EU's natural gas consumption. This report contributes to the ongoing the Heat Roadmap Europe project series

Measuring Replicative Life Span in the Budding Yeast

Aging is a degenerative process characterized by a progressive deterioration of cellular components and organelles resulting in mortality. The budding yeast Saccharomyces cerevisiae has been used extensively to study the biology of aging, and several determinants of yeast longevity have been shown to be conserved in multicellular eukaryotes, including worms, flies, and mice 1. Due to the lack of easily quantified age-associated phenotypes, aging in yeast has been assayed almost exclusively by measuring the life span of cells in different contexts, with two different life span paradigms in common usage 2. Chronological life span refers to the length of time that a mother cell can survive in a non-dividing, quiescence-like state, and is proposed to serve as a model for aging of post-mitotic cells in multicellular eukaryotes. Replicative life span, in contrast, refers the number of daughter cells produced by a mother cell prior to senescence, and is thought to provide a model of aging in mitotically active cells. Here we present a generalized protocol for measuring the replicative life span of budding yeast mother cells. The goal of the replicative life span assay is to determine how many times each mother cell buds. The mother and daughter cells can be easily differentiated by an experienced researcher using a standard light microscope (total magnification 160X), such as the Zeiss Axioscope 40 or another comparable model. Physical separation of daughter cells from mother cells is achieved using a manual micromanipulator equipped with a fiber-optic needle. Typical laboratory yeast strains produce 20-30 daughter cells per mother and one life span experiment requires 2-3 weeks

Association Between Homocysteine and Vascular Calcification Incidence, Prevalence, and Progression in the MESA Cohort.

Background While elevated homocysteine has been associated with calcification in several studies, its importance as a cardiovascular risk factor remains unclear. This study examines the relationship between homocysteine and vascular and valve calcification in the MESA (Multi-ethnic Study of Atherosclerosis) cohort. Methods and Results MESA participants with baseline homocysteine measurements and cardiac computed tomography scans were included (N=6789). Baseline and follow-up assessment of vascular (coronary artery [CAC], descending thoracic aorta [DTAC]) and valve (aortic valve [AVC], mitral annular [MAC]) calcification was performed. Prevalence ratio/relative risk regression was used to assess the relationship of homocysteine with prevalent and incident calcification, and multivariable logistic regression was used to assess associations between homocysteine and calcification progression. Elevated homocysteine was associated with greater relative risk of prevalent and incident CAC and incident DTAC. We also identified a strong association between elevated homocysteine and CAC and DTAC progression. Elevated homocysteine was found to confer a >2-fold increased risk of severe CAC progression (defined as ΔCAC ≥100/year) and an ≈1.5-fold increased risk for severe DTAC progression (defined as ΔDTAC ≥100/year). Conclusions To our knowledge, this is the first study demonstrating an association between elevated homocysteine and both incidence and progression of coronary and extra-coronary vascular calcification. Our findings suggest a potential role for elevated homocysteine as a risk factor for severe vascular calcification progression. Future studies are warranted to further assess the utility of homocysteine as a biomarker for vascular calcification incidence and progression. Clinical Trial Registration https://www.clinicaltrials.gov/. Unique identifier: NCT00005487

Thermal modelling of Advanced LIGO test masses

High-reflectivity fused silica mirrors are at the epicentre of current advanced gravitational wave detectors. In these detectors, the mirrors interact with high power laser beams. As a result of finite absorption in the high reflectivity coatings the mirrors suffer from a variety of thermal effects that impact on the detectors performance. We propose a model of the Advanced LIGO mirrors that introduces an empirical term to account for the radiative heat transfer between the mirror and its surroundings. The mechanical mode frequency is used as a probe for the overall temperature of the mirror. The thermal transient after power build-up in the optical cavities is used to refine and test the model. The model provides a coating absorption estimate of 1.5 to 2.0 ppm and estimates that 0.3 to 1.3 ppm of the circulating light is scattered on to the ring heater.Comment: 14 pages, 9 figure