The regional-scale surface mass balance of Pine Island Glacier, West Antarctica, over the period 2005--2014, derived from airborne radar soundings and neutron probe measurements

We derive recent surface mass balance (SMB) estimates from airborne radar observations along the iSTAR traverse (2013, 2014) at Pine Island Glacier (PIG), West Antarctica. Ground-based neutron probe measurements provide information of snow and firn density with depth at 22 locations and were used to date internal annual reflection layers. The 2005 layer was traced for a total distance of 2367 km to determine annual mean SMB for the period 2005–2014. Using complementary SMB estimates from two regional climate models, RACMO2.3p2 and MAR, and a geostatistical kriging scheme, we determine a regional-scale SMB distribution with similar main characteristics to that determined for the period 1985–2009 in previous studies. Local departures exist for the northern PIG slopes, where the orographic precipitation shadow effect appears to be more pronounced in our observations, and the southward interior, where the SMB gradient is more pronounced in previous studies. We derive total mass inputs of 79.9 +/- 19.2 and 82.1 +/- 19.2 Gt yr-1 to the PIG basin based on complementary ASIRAS–RACMO and ASIRAS–MAR SMB estimates, respectively. These are not significantly different to the value of 78.3 +/- 6.8 Gt yr-1 for the period 1985–2009. Thus, there is no evidence of a secular trend at decadal scales in total mass input to the PIG basin. We note, however, that our estimated uncertainty is more than twice the uncertainty for the 1985–2009 estimate on total mass input. Our error analysis indicates that uncertainty estimates on total mass input are highly sensitive to the selected krige methodology and assumptions made on the interpolation error, which we identify as the main cause for the increased uncertainty range compared to the 1985–2009 estimates

The assessment of science: the relative merits of post- publication review, the impact factor, and the number of citations

The assessment of scientific publications is an integral part of the scientific process. Here we investigate three methods of assessing the merit of a scientific paper: subjective post-publication peer review, the number of citations gained by a paper, and the impact factor of the journal in which the article was published. We investigate these methods using two datasets in which subjective post-publication assessments of scientific publications have been made by experts. We find that there are moderate, but statistically significant, correlations between assessor scores, when two assessors have rated the same paper, and between assessor score and the number of citations a paper accrues. However, we show that assessor score depends strongly on the journal in which the paper is published, and that assessors tend to over-rate papers published in journals with high impact factors. If we control for this bias, we find that the correlation between assessor scores and between assessor score and the number of citations is weak, suggesting that scientists have little ability to judge either the intrinsic merit of a paper or its likely impact. We also show that the number of citations a paper receives is an extremely error-prone measure of scientific merit. Finally, we argue that the impact factor is likely to be a poor measure of merit, since it depends on subjective assessment. We conclude that the three measures of scientific merit considered here are poor; in particular subjective assessments are an error-prone, biased, and expensive method by which to assess merit. We argue that the impact factor may be the most satisfactory of the methods we have considered, since it is a form of pre-publication review. However, we emphasise that it is likely to be a very error-prone measure of merit that is qualitative, not quantitative

969-99 Biocompatible Mechanical Left Ventricular Support: Potential Alternative to Transplantation

Use of mechanical circulatory support has been limited by its associated bleeding and thrombotic complications. Blood contact with an artificial surface results in a well-deined pattern of hematologic alterations. The TCI HeartMate® left ventricular assist device (LVAD) is an implantable circulatory support pump currently used as a bridge to transplantation. Its textured blood contacting surfaces result in a formation of an adherent pseudoneointimal lining which eliminates the direct interaction of blood elements with the artificial surface. To determine if this biological lining could mitigate the stereotypical blood-synthetic surface interactions, we studied eight patients who underwent implantation at our institution over a 10 month period from 5/93 to 3/94. Seven of the 8 patients were bridged to transplantation. Three patients were transplanted within 10 days and one month data could not be obtained. Hemodynamic and hemostatic parameters (mean±sd) were studied as follows:Pre-implantPOD 7POD 28Cardiac index (I/min/m2)1.8±0.73.2±0.43.1±0.5Systolic BP (mmHg)759±6.8125.8±9.7130.4±8.1Hemoglobin (mg/dl)7.4±1.88.2±1.69.6±2.0Plasma free hemoglobin (mg/dl)15.4±1.76.4±2.36.8±1.9Prothrombin time (sec)14.2±1.113.4±0.713.3±0.7Partial thromboplastin time (sec)56.7±15.931.8±4.837.6±11.9Platelet count (× 103lcu mm)250±81269±63325±37In vitro platelet reactivity to the agonist ADP remained normal pre and post implantation. Average perioperative blood requirements included PRBC, 3.3±1.3 units; platelets, 2.3±4.5 units; fresh frozen plasma, 2±1.9 units. No blood products were required after postoperative day 2.We conclude that TCI LVAD support improves hemodynamics and can bridge patients in pre-implant cardiogenic shock to transplantation. Furthermore, no red cell destruction or hemostatic and thrombotic complications were observed despite one month of support without anticoagulation therapy. Therefore, as the donor shortage continues, LVADs with biocompatible surfaces may provide an alternative to cardiac transplantation

Transcriptomes of post-mitotic neurons identify the usage of alternative pathways during adult and embryonic neuronal differentiation

Original Panther analysis tool data tables showing values and p -values for overrepresentation data sets. (XLSX 21 kb

Glaciological characteristics in the Dome Fuji region and new assessment for 1.5 Ma old ice

The retrieval of a continuous Antarctic ice-core record dating back 1.5 Ma is a key objective in palaeo-climatologyin order to understand why the frequency of ice ages changed from 40 ka to 100 ka approximately 1 Ma ago. Here,we investigate the probability that the Dome Fuji region in East Antarctica contains ice more than 1.5 Ma old.We use a new radar dataset acquired in the Antarctic seasons 2014/15 and 2016/17 to improve the ice thickness map. Compared to previous maps of the region, the new dataset shows a more complex landscape with networks of valleys and mountain plateaus. We use the new dataset as input in a thermokinematic model that incorporates uncertainties in geothermal heat flux values in order to improve the predictions of potential ice-core sites. Our results indicate several areas of interest, especially the region immediately south of Dome Fuji station appears to be a good candidate site. An initial assessment of basal conditions revealed the existence of several wet-based areas and further radar data analysis shows overall high continuity of layer stratigraphy in the region. Thus, if a new drill operation were to take place in this area, extending the age-depth information from the Dome Fuji ice core to a new ice-core drill site is a viable option

Phylogenomics of the Reproductive Parasite Wolbachia pipientis wMel: A Streamlined Genome Overrun by Mobile Genetic Elements

The complete sequence of the 1,267,782 bp genome of Wolbachia pipientis wMel, an obligate intracellular bacteria of Drosophila melanogaster, has been determined. Wolbachia, which are found in a variety of invertebrate species, are of great interest due to their diverse interactions with different hosts, which range from many forms of reproductive parasitism to mutualistic symbioses. Analysis of the wMel genome, in particular phylogenomic comparisons with other intracellular bacteria, has revealed many insights into the biology and evolution of wMel and Wolbachia in general. For example, the wMel genome is unique among sequenced obligate intracellular species in both being highly streamlined and containing very high levels of repetitive DNA and mobile DNA elements. This observation, coupled with multiple evolutionary reconstructions, suggests that natural selection is somewhat inefficient in wMel, most likely owing to the occurrence of repeated population bottlenecks. Genome analysis predicts many metabolic differences with the closely related Rickettsia species, including the presence of intact glycolysis and purine synthesis, which may compensate for an inability to obtain ATP directly from its host, as Rickettsia can. Other discoveries include the apparent inability of wMel to synthesize lipopolysaccharide and the presence of the most genes encoding proteins with ankyrin repeat domains of any prokaryotic genome yet sequenced. Despite the ability of wMel to infect the germline of its host, we find no evidence for either recent lateral gene transfer between wMel and D. melanogaster or older transfers between Wolbachia and any host. Evolutionary analysis further supports the hypothesis that mitochondria share a common ancestor with the α-Proteobacteria, but shows little support for the grouping of mitochondria with species in the order Rickettsiales. With the availability of the complete genomes of both species and excellent genetic tools for the host, the wMel–D. melanogaster symbiosis is now an ideal system for studying the biology and evolution of Wolbachia infections