End-Cretaceous marine mass extinction not caused by productivity collapse

An asteroid impact at the end of the Cretaceous caused mass extinction, but extinction mechanisms are not well-understood. The collapse of sea surface to sea floor carbon isotope gradients has been interpreted as reflecting a global collapse of primary productivity (Strangelove Ocean) or export productivity (Living Ocean), which caused mass extinction higher in the marine food chain. Phytoplankton-dependent benthic foraminifera on the deep-sea floor, however, did not suffer significant extinction, suggesting that export productivity persisted at a level sufficient to support their populations. We compare benthic foraminiferal records with benthic and bulk stable carbon isotope records from the Pacific, Southeast Atlantic, and Southern Oceans. We conclude that end-Cretaceous decrease in export productivity was moderate, regional, and insufficient to explain marine mass extinction. A transient episode of surface ocean acidification may have been the main cause of extinction of calcifying plankton and ammonites, and recovery of productivity may have been as fast in the oceans as on land

Efficiency of priming methods in crop establishment of Ginger (Zingiber officinale Rosc.)

The present research work was conducted to evaluate the effect of different priming methods on Zingiber officinale Rosc. variety Karthika. Hydropriming was done by immersing the ginger rhizomes in distilled water for varied time durations (6, 12, 24, 36 and 48 hour), and for halopriming different concentrations (50mM,100mM, 250mM and 500mM) of sodium chloride (NaCl) solution was used for different time durations (6, 12, 18 and 24 hour). The primed plants showed fast germination than unprimed ones. The germination percentage of haloprimed (50 mM NaCl for 24 hour) plants was 89.22% and in hydropriming it was 90.33% (24 hours). But in the case of unprimed (control) plants, the germination percentage was only 55.11%. The present study showed that the optimum time duration for priming in ginger was 24 hours. In halopriming, the growth was highest in 50 mM NaCl for 24 hours. The carbohydrate content and photosynthetic pigment content were highest in primed plants when compared to unprimed plants.When comparing both priming methods, the haloprimed plants showed highest chlorophyll content and carbohydrate content than the hydroprimed ones. But, regarding the yield, hydroprimed plants produced more tillers and thus more yield. Since, ginger is cultivated for mainly for the rhizomes, among the two priming methods investigated, hydropriming was found to be more promising than halopriming in terms of yield

Multiparameter flow cytometry for the characterisation of extracellular markers on human mesenchymal stem cells

Extracellular surface proteins are used to identify fully-functional human mesenchymal stem cells (hMSCs) in a mixed population. Here, a multiparameter flow cytometry assay was developed to examine the expression of several bone marrow-derived hMSC markers simultaneously at the single cell level. The multiparameter approach demonstrates a depth of analysis that goes far beyond the conventional single or dual staining methods. CD73, CD90 and CD105 were chosen as positive markers as they are expressed on multipotent hMSCs, whilst CD34 and HLA-DR were chosen as negative indicators. Single colour analysis suggested a population purity of 100 %; in contrast, when analysed via the multiparameter method, the CD73/CD105/CD90/HLA-DR/CD34 phenotypes represented 94.5 ± 1.3 % of the total cell population. Also, although CD271 has been posited as a definite early stage hMSC marker, here we show it is not present on pre-passage cells, highlighting the need for careful marker selection. © 2013 Springer Science+Business Media Dordrecht

Astrophysical Ionizing Radiation and the Earth: A Brief Review and Census of Intermittent Intense Sources

Cosmic radiation backgrounds are a constraint on life, and their distribution will affect the Galactic Habitable Zone. Life on Earth has developed in the context of these backgrounds, and characterizing event rates will elaborate the important influences. This in turn can be a base for comparison with other potential life-bearing planets. In this review we estimate the intensities and rates of occurrence of many kinds of strong radiation bursts by astrophysical entities ranging from gamma-ray bursts at cosmological distances to the Sun itself. Many of these present potential hazards to the biosphere: on timescales long compared with human history, the probability of an event intense enough to disrupt life on the land surface or in the oceans becomes large. We enumerate the known sources of radiation and characterize their intensities at the Earth and rates or upper limits on these quantities. When possible, we estimate a "lethal interval", our best estimate of how often a major extinction-level event is probable given the current state of knowledge; we base these estimates on computed or expected depletion of stratospheric ozone. In general, moderate level events are dominated by the Sun, but the far more severe infrequent events are probably dominated by gamma-ray bursts and supernovae. We note for the first time that so-called "short-hard" gamma-ray bursts are a substantial threat, comparable in magnitude to supernovae and greater than that of the higher-luminosity long bursts considered in most past work. Given their precursors, short bursts may come with little or no warning.Comment: to be published in Astrobiolog

Characterization of human mesenchymal stem cells from multiple donors and the implications for large scale bioprocess development

Cell-based therapies have the potential to contribute to global healthcare, whereby the use of living cells and tissues can be used as medicinal therapies. Despite this potential, many challenges remain before the full value of this emerging field can be realized. The characterization of input material for cell-based therapy bioprocesses from multiple donors is necessary to identify and understand the potential implications of input variation on process development. In this work, we have characterized bone marrow derived human mesenchymal stem cells (BM-hMSCs) from multiple donors and discussed the implications of the measurable input variation on the development of autologous and allogeneic cell-based therapy manufacturing processes. The range of cumulative population doublings across the five BM-hMSC lines over 30 days of culture was 5.93, with an 18.2% range in colony forming efficiency at the end of the culture process and a 55.1% difference in the production of interleukin-6 between these cell lines. It has been demonstrated that this variation results in a range in the process time between these donor hMSC lines for a hypothetical product of over 13 days, creating potential batch timing issues when manufacturing products from multiple patients. All BM-hMSC donor lines demonstrated conformity to the ISCT criteria but showed a difference in cell morphology. Metabolite analysis showed that hMSCs from the different donors have a range in glucose consumption of 26.98 pmol cell−1 day−1, Lactate production of 29.45 pmol cell−1 day−1 and ammonium production of 1.35 pmol cell−1 day−1, demonstrating the extent of donor variability throughout the expansion process. Measuring informative product attributes during process development will facilitate progress towards consistent manufacturing processes, a critical step in the translation cell-based therapies

Physiological predictors of acute coronary syndromes: emerging insights from the plaque to the vulnerable patient

In this review, the authors explore the evolving evidence linking physiological assessment of coronary artery disease with plaque progression and vulnerability. Reducing adverse clinical events remains the ultimate goal for diagnostic tests, and this review highlights evidence supporting the prognostic value of physiological metrics in predicting outcomes. Historical and contemporary studies support synergy among lesion severity, ischemia, plaque vulnerability, and patient prognosis. Ischemia contributes to clinical events through association with plaque burden, but this review addresses the emerging concept that it associates with atherothrombosis via disturbed lesion hemodynamics. Biomechanical pathophysiological forces including endothelial shear stress-the frictional force generated by blood flow on the vessel wall-are increasingly linked with atherogenesis, vulnerable plaque morphology, and platelet and leukocyte activation. The authors conclude by transitioning from the model of the vulnerable plaque to the concept of the "vulnerable patient," looking more broadly at physiological contributors to Virchow's triad underpinning acute coronary syndrome

Achievement goals and motivational responses in tennis: Does the context matter?

Objectives: This study examined: (a) whether athletes’ goal orientations differ across training and competition; (b) whether goal orientations predict effort, enjoyment, and psychological skill use differently in training and competition; and (c) whether goal orientations predict perceived improvement in training and perceived performance in competition. Method: Participants were 116 competitive tennis players (mean age = 19.99, SD = 5.82), who completed questionnaires measuring goal orientations, effort, enjoyment, and psychological skill use in training and competition, perceived improvement in training, and perceived performance in competition. Results: Dependent t-tests revealed that athletes reported higher task orientation in training than in competition and higher ego orientation in competition than in training, while Pearson product-moment correlations revealed a high cross-contextual consistency for both task and ego goal orientations between training and competition. Regression analyses indicated that task orientation predicted positively effort, enjoyment, self-talk, and goal setting in both contexts, perceived improvement in training, and perceived performance in competition. An interaction effect also emerged whereby ego orientation predicted positively effort in competition only when task orientation was low or average. Conclusions: The findings suggest that goal orientations may differ between training and competition; task orientation is the goal that should be promoted in both contexts; and the context may affect the relationship between goal orientations and effort, enjoyment, and goal setting

Biomonitoring of Exposure in Farmworker Studies

Although biomonitoring has been used in many occupational and environmental health and exposure studies, we are only beginning to understand the complexities and uncertainties involved with the biomonitoring process—from study design, to sample collection, to chemical analysis—and with interpreting the resulting data. We present an overview of concepts that should be considered when using biomonitoring or biomonitoring data, assess the current status of biomonitoring, and detail potential advancements in the field that may improve our ability to both collect and interpret biomonitoring data. We discuss issues such as the appropriateness of biomonitoring for a given study, the sampling time frame, temporal variability in biological measurements to nonpersistent chemicals, and the complex issues surrounding data interpretation. In addition, we provide recommendations to improve the utility of biomonitoring in farmworker studies