Persistence of full glacial conditions in the central Pacific until 15,000 years ago

The magnitude of atmospheric cooling during the Last Glacial Maximum and the timing of the transition into the current interglacial period remain poorly constrained in tropical regions, partly because of a lack of suitable climate records. Glacial moraines provide a method of reconstructing past temperatures, but they are relatively rare in the tropics. Here we present a reconstruction of atmospheric temperatures in the central Pacific during the last deglaciation on the basis of cosmogenic ^3He ages of moraines and numerical modelling of the ice cap on Mauna Kea volcano, Hawaii—the only highland in the central Pacific on which moraines that formed during the last glacial period are preserved. Our reconstruction indicates that the Last Glacial Maximum occurred between 19,000 and 16,000 years ago in this region and that temperatures at high elevations were about 7 °C lower than today during this interval. Glacial retreat began about 16,000 years ago, but temperatures were still about 6.5 °C lower than today until 15,000 years ago. When combined with estimates of sea surface temperatures in the central Pacific Ocean, our reconstruction indicates that the lapse rate during the Last Glacial Maximum was higher than at present, which is consistent with the proposal that the atmosphere was drier at that time. Furthermore, the persistence of full glacial conditions until 15,000 years ago is consistent with the relatively late and abrupt transition to warmer temperatures in Greenland5, indicating that there may have been an atmospheric teleconnection between the central Pacific and North Atlantic regions during the last deglaciation

Thermal imprint of rift-related processes in orogens as recorded in the Pyrenees

International audience19 The extent to which heat recorded in orogens reflects thermal conditions inherited from 20 previous rift-related processes is still debated and poorly documented. As a case study, we 21 examine the Mauléon basin in the north-western Pyrenees that experienced both extreme 22 crustal thinning and tectonic inversion within a period of ~30 Myrs. To constrain the time-23 temperature history of the basin in such a scenario, we provide new detrital zircon fission-24 track and (U-Th-Sm)/He thermochronology data. The role of rift-related processes in 25 subsequent collision is captured by inverse modeling of our thermochronological data, using 26 relationships between zircon (U-Th-Sm)/He ages and uranium content, combined with 27 thermo-kinematic models of a rift-orogen cycle. We show that the basin recorded significant 28 heating at about 100 Ma characterized by high geothermal gradients (~80°C/km). Our 29 thermo-kinematic modeling and geological constraints support the view that subcontinental 30 lithospheric mantle was exhumed at that time below the Mauléon basin. Such a high 31 geothermal gradient lasted 30 Myr after onset of convergence at ~83 Ma and was relaxed 32 during the collision phase from ~50 Ma. This study suggests that heat needed for ductile 33 shortening during convergence, is primarily inherited from extension rather than being only 34 related to tectonic and/or sedimentary burial. This should have strong implications on tectonic 35 reconstructions in many collision belts that resulted from inversion of hyper-extended rift 36 basins

Land systems as surrogates for biodiversity in conservation planning

Environmental surrogates (land classes) for the distribution of biodiversity are increasingly being used for conservation planning. However; data that demonstrate coincident patterns in land classes and biodiversity are limited. We ask the overall question, "Are land systems effective surrogates for the spatial configuration of biodiversity for conservation planning?" and we address three specific questions: (1) Do different land systems represent different biological assemblages.? (2) Do biological assemblages on the same land system remain similar with increasing geographic separation? and (3) Do biological assemblages on the same land system remain similar with increasing land system isolation? Vascular plants, invertebrates, and microbiota were surveyed from 24 sites in four land systems in and northwest New South Wales, Australia. Within each land system, sites were located to give a hierarchy of inter-site distances, and land systems were classified as either "low isolation" (large and continuous) or "high isolation" (small patches interspersed among other land systems). Each type of land system supported components of biodiversity either not found, or found infrequently, on other land systems, suggesting that land systems function as surrogates for biodiversity, and that conservation-area networks representing land-system diversity will also represent biological diversity. However, the majority of taxa were found on more than one land-system type, suggesting that a large proportion of the plant, arthropod, and microbial biodiversity may be characterized by widespread species with low fidelity to particular land systems. Significant relationships between geographic distance among sites and differences among assemblages were revealed for all taxa except the microbiota. Therefore, as sites on the same land system were located farther apart, the assemblages at those sites became more different. This finding strongly suggests that conservation planning based on land-system diversity should also sample the geographic range occupied by each land system. Land-system isolation was not revealed to be a significant Source of variation in assemblage composition. Our research finds support for environmental surrogates for biodiversity in conservation planning, specifically the use of land systems and similarly derived land classifications. However, the need for explicit modeling of geographic distance in conservation planning is clearly indicated

Non-Small Cell Lung Cancer Cells Expressing CD44 Are Enriched for Stem Cell-Like Properties

Background: The cancer stem cell theory hypothesizes that cancers are perpetuated by cancer stem cells (CSC) or tumor initiating cells (TIC) possessing self-renewal and other stem cell-like properties while differentiated non-stem/initiating cells have a finite life span. To investigate whether the hypothesis is applicable to lung cancer, identification of lung CSC and demonstration of these capacities is essential. Methodology/Principal Finding: The expression profiles of five stem cell markers (CD34, CD44, CD133, BMI1 and OCT4) were screened by flow cytometry in 10 lung cancer cell lines. CD44 was further investigated by testing for in vitro and in vivo tumorigenecity. Formation of spheroid bodies and in vivo tumor initiation ability were demonstrated in CD44+ cells of 4 cell lines. Serial in vivo tumor transplantability in nude mice was demonstrated using H1299 cell line. The primary xenografts initiated from CD44+ cells consisted of mixed CD44+ and CD44- cells in similar ratio as the parental H1299 cell line, supporting in vivo differentiation. Semi-quantitative Real-Time PCR (RT-PCR) showed that both freshly sorted CD44+ and CD44+ cells derived from CD44+-initiated tumors expressed the pluripotency genes OCT4/POU5F1, NANOG, SOX2. These stemness markers were not expressed by CD44- cells. Furthermore, freshly sorted CD44+ cells were more resistant to cisplatin treatment with lower apoptosis levels than CD44- cells. Immunohistochemical analysis of 141 resected non-small cell lung cancers showed tumor cell expression of CD44 in 50.4% of tumors while no CD34, and CD133 expression was observed in tumor cells. CD44 expression was associated with squamous cell carcinoma but unexpectedly, a longer survival was observed in CD44-expressing adenocarcinomas. Conclusion/Significance: Overall, our results demonstrated that stem cell-like properties are enriched in CD44-expressing subpopulations of some lung cancer cell lines. Further investigation is required to clarify the role of CD44 in tumor cell renewal and cancer propagation in the in vivo environment.© 2010 Leung et al.published_or_final_versio

Short-Range Ising Spin Glass: Multifractal Properties

The multifractal properties of the Edwards-Anderson order parameter of the short-range Ising spin glass model on d=3 diamond hierarchical lattices is studied via an exact recursion procedure. The profiles of the local order parameter are calculated and analysed within a range of temperatures close to the critical point with four symmetric distributions of the coupling constants (Gaussian, Bimodal, Uniform and Exponential). Unlike the pure case, the multifractal analysis of these profiles reveals that a large spectrum of the $\alpha$-H\"older exponent is required to describe the singularities of the measure defined by the normalized local order parameter, at and below the critical point. Minor changes in these spectra are observed for distinct initial distributions of coupling constants, suggesting an universal spectra behavior. For temperatures slightly above T_{c}, a dramatic change in the $F(\alpha)$ function is found, signalizing the transition.Comment: 8 pages, LaTex, PostScript-figures included but also available upon request. To be published in Physical Review E (01/March 97

Metabolic requirement of septic shock patients before and after liberation from mechanical ventilation

Objectives:Negative energy balance can impair regeneration of the respiratory epithelium and limit the functionality of respiratory muscles, which can prolong mechanical ventilation. The present study sought to quantify and identify the difference in energy expenditure of patients with septic shock during and upon liberation from mechanical ventilation. Methods:Patients admitted into intensive care with initial diagnosis of septic shock and mechanical ventilation-dependent were recruited. Their metabolic requirements before and after liberation from mechanical ventilation were measured by indirect calorimetry. A paired t-test was used to examine the variance between the two modes of breathing and a Spearman rho correlation coefficient to examine relationship of selected indicators.Results: Thirty-five patients, 20 males and 15 females mean age 69 ±10 years, body height of 1.58 ±0.08 meters, and ideal body mass 59.01 ±7.63 kg were recruited. Median APACHEII score was 22, length of stay in the intensive care was 45 ±65 days and duration on mechanical ventilation was 24 ±25 days. Measured energy expenditure during ventilation was 2090 ±489 kcal∙d-1 upon liberation from ventilation was 1910 ±579 kcal∙d-1 and actual caloric intake was 1148 ±495 kcal∙d-1. Measured energy expenditure (p=0.02), actual calories provision and energy expenditure with (p=0.00) and without (p=0.00) ventilator support were all significantly different. Mean carbohydrate oxidation was 0.17 ±0.09 g·min-1 when patients were on mechanical ventilation compared to 0.14 ±0.08 g·min-1 upon liberation, however, this difference was not statistically significant. Furthermore, mean lipid oxidation was 0.08 ±0.05 g·min-1 during mechanical ventilation and 0.09±0.07 g·min-1 upon liberation, which was also not statistically different. Comparison of carbohydrate utilization and lipid oxidation was not different during (0.7±0.36 vs 0.75±0.47 kcal·min-1) and upon liberation from mechanical ventilation (0.55±0.33 vs 0.78±0.59 kcal·min-1).Conclusions: This study examined energy expenditure and substrate oxidation within a single cohort of patients with and without mechanical ventilation. Measured energy expenditure was found to be higher during mechanical ventilation. The possible explanations were positive pressure support from ventilation, the repeated cycle of “rest” and “work” during weaning from ventilators and the asynchronization between self-initiated breathing effort and the ventilatory support. The change energy expenditure with and without ventilatory support should be monitored so that mismatch could be aligned. Future studies are important to examine whether matching energy expenditure with energy intake would promote positive outcomes.<br/

Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction

The mechanisms that drive the upwelling of chemical heterogeneity from the lower to upper mantle (e.g., thermal versus compositional buoyancy) are key to our understanding of whole mantle con- vective processes. We address these issues through a receiver function study on new seismic data from recent deployments located on the Afar Triple Junction, a location associated with deep mantle upwelling. The detailed images of upper mantle and mantle transition zone structure illuminate features that give insights into the nature of upwelling from the deep Earth. A seismic low-velocity layer directly above the mantle transition zone, interpreted as a stable melt layer, along with a prominent 520 km discontinuity sug- gest the presence of a hydrous upwelling. A relatively uniform transition zone thickness across the region suggests a weak thermal anomaly (<100 K) may be present and that upwelling must be at least partly driven by compositional buoyancy. The results suggest that the lower mantle is a source of volatile rich, chemically distinct upwellings that influence the structure of the upper mantle, and potentially the chemis- try of surface lavas