NASA's supercomputing experience

A brief overview of NASA's recent experience in supercomputing is presented from two perspectives: early systems development and advanced supercomputing applications. NASA's role in supercomputing systems development is illustrated by discussion of activities carried out by the Numerical Aerodynamical Simulation Program. Current capabilities in advanced technology applications are illustrated with examples in turbulence physics, aerodynamics, aerothermodynamics, chemistry, and structural mechanics. Capabilities in science applications are illustrated by examples in astrophysics and atmospheric modeling. Future directions and NASA's new High Performance Computing Program are briefly discussed

The Effect of Income on Educational Attainment: Evidence from State Earned Income Tax Credit Expansions

As of the early 2000s, the gap in college enrollment between children growing up in the highest income quartile and the lowest income quartile was over 50 percentage points (Bailey and Dynarski 2011). While previous work has analyzed the impact of various federal and state financial aid programs on college enrollment rates among low and moderate-income households, the Earned Income Tax Credit (EITC) has largely been overlooked as a potential source of financial aid. As of the 2011 tax year, the maximum federal EITC benefit was nearly $6,000, worth up to 45$1,000, 18-23 year old children growing up in likely EITC-eligible households are 1 percentage point more likely to have ever enrolled in college and 0.3 percentage points more likely to complete a bachelor’s degree

Cryogenic Fluid Pumping Applications

Discussion GroupCalculating efficiency, power & considerations Condition monitoring Cryogenic pump system components Accessories to cryogenic pump systems Shaft supports: bushings, bearings Rotordynamics Balance requirements for rotating components Bearing life and how to extend it Materials of construction & specifications Preventative maintenance (PM) requirements Vibration standards & monitoring Pump testing requirements & applicable test tolerances Troubleshooting Pump installation – steps and challenges Pump sizing for various cryogenic applications Motor sizing for cryogenic pumps Different kinds of cryogenic pumps and where they should be applied Cryogenic pump specific speed Marine & floating applications for cryogenic pumps Submerged motor design and its benefits Hazardous area classification for cryogenic pumps & systems Preservation and long-term storage of cryogenic pumps System design requirements Pressure vessel design Cryogenic pumping applications Pros and cons of conventional pump design versus Cryogenic submerged pump Pump columns/column diameters determination and benefit

Cryogenic Fluid Pumping Applications

Discussion Grou

What makes species unique? The contribution of proteins with obscure features

BACKGROUND: Proteins with obscure features (POFs), which lack currently defined motifs or domains, represent between 18% and 38% of a typical eukaryotic proteome. To evaluate the contribution of this class of proteins to the diversity of eukaryotes, we performed a comparative analysis of the predicted proteomes derived from 10 different sequenced genomes, including budding and fission yeast, worm, fly, mosquito, Arabidopsis, rice, mouse, rat, and human. RESULTS: Only 1,650 protein groups were found to be conserved among these proteomes (BLAST E-value threshold of 10(-6)). Of these, only three were designated as POFs. Surprisingly, we found that, on average, 60% of the POFs identified in these 10 proteomes (44,236 in total) were species specific. In contrast, only 7.5% of the proteins with defined features (PDFs) were species specific (17,554 in total). As a group, POFs appear similar to PDFs in their relative contribution to biological functions, as indicated by their expression, participation in protein-protein interactions and association with mutant phenotypes. However, POF have more predicted disordered structure than PDFs, implying that they may exhibit preferential involvement in species-specific regulatory and signaling networks. CONCLUSION: Because the majority of eukaryotic POFs are not well conserved, and by definition do not have defined domains or motifs upon which to formulate a functional working hypothesis, understanding their biochemical and biological functions will require species-specific investigations

Role of protein kinase C and μ-opioid receptor (MOPr) desensitization in tolerance to morphine in rat locus coeruleus neurons

In morphine tolerance a key question that remains to be answered is whether μ-opioid receptor (MOPr) desensitization contributes to morphine tolerance, and if so by what cellular mechanisms. Here we demonstrate that MOPr desensitization can be observed in single rat brainstem locus coeruleus (LC) neurons following either prolonged (> 4 h) exposure to morphine in vitro or following treatment of animals with morphine in vivo for 3 days. Analysis of receptor function by an operational model indicated that with either treatment morphine could induce a profound degree (70–80%) of loss of receptor function. Ongoing PKC activity in the MOPr-expressing neurons themselves, primarily by PKCα, was required to maintain morphine-induced MOPr desensitization, because exposure to PKC inhibitors for only the last 30–50 min of exposure to morphine reduced the MOPr desensitization that was induced both in vitro and in vivo. The presence of morphine was also required for maintenance of desensitization, as washout of morphine for > 2 h reversed MOPr desensitization. MOPr desensitization was homologous, as there was no change in α2-adrenoceptor or ORL1 receptor function. These results demonstrate that prolonged morphine treatment induces extensive homologous desensitization of MOPrs in mature neurons, that this desensitization has a significant PKC-dependent component and that this desensitization underlies the maintenance of morphine tolerance

The Red Sea, Coastal Landscapes, and Hominin Dispersals

This chapter provides a critical assessment of environment, landscape and resources in the Red Sea region over the past five million years in relation to archaeological evidence of hominin settlement, and of current hypotheses about the role of the region as a pathway or obstacle to population dispersals between Africa and Asia and the possible significance of coastal colonization. The discussion assesses the impact of factors such as topography and the distribution of resources on land and on the seacoast, taking account of geographical variation and changes in geology, sea levels and palaeoclimate. The merits of northern and southern routes of movement at either end of the Red Sea are compared. All the evidence indicates that there has been no land connection at the southern end since the beginning of the Pliocene period, but that short sea crossings would have been possible at lowest sea-level stands with little or no technical aids. More important than the possibilities of crossing the southern channel is the nature of the resources available in the adjacent coastal zones. There were many climatic episodes wetter than today, and during these periods water draining from the Arabian escarpment provided productive conditions for large mammals and human populations in coastal regions and eastwards into the desert. During drier episodes the coastal region would have provided important refugia both in upland areas and on the emerged shelves exposed by lowered sea level, especially in the southern sector and on both sides of the Red Sea. Marine resources may have offered an added advantage in coastal areas, but evidence for their exploitation is very limited, and their role has been over-exaggerated in hypotheses of coastal colonization

Cryogenic Fluid Pumping Applications

Discussion GroupCalculating efficiency, power & considerations Condition monitoring Cryogenic pump system components Accessories to cryogenic pump systems Shaft supports: bushings, bearings Rotordynamics Balance requirements for rotating components Bearing life and how to extend it Materials of construction & specifications Preventative maintenance (PM) requirements Vibration standards & monitoring Pump testing requirements & applicable test tolerances Troubleshooting Pump installation – steps and challenges Pump sizing for various cryogenic applications Motor sizing for cryogenic pumps Different kinds of cryogenic pumps and where they should be applied Cryogenic pump specific speed Marine & floating applications for cryogenic pumps Submerged motor design and its benefits Hazardous area classification for cryogenic pumps & systems Preservation and long-term storage of cryogenic pumps System design requirements Pressure vessel design Cryogenic pumping applications Pros and cons of conventional pump design versus Cryogenic submerged pump Pump columns/column diameters determination and benefit

Cryogenic Fluid Pumping Applications

Discussion Grou

Mechanisms explaining transitions between tonic and phasic firing in neuronal populations as predicted by a low dimensional firing rate model

Several firing patterns experimentally observed in neural populations have been successfully correlated to animal behavior. Population bursting, hereby regarded as a period of high firing rate followed by a period of quiescence, is typically observed in groups of neurons during behavior. Biophysical membrane-potential models of single cell bursting involve at least three equations. Extending such models to study the collective behavior of neural populations involves thousands of equations and can be very expensive computationally. For this reason, low dimensional population models that capture biophysical aspects of networks are needed. \noindent The present paper uses a firing-rate model to study mechanisms that trigger and stop transitions between tonic and phasic population firing. These mechanisms are captured through a two-dimensional system, which can potentially be extended to include interactions between different areas of the nervous system with a small number of equations. The typical behavior of midbrain dopaminergic neurons in the rodent is used as an example to illustrate and interpret our results. \noindent The model presented here can be used as a building block to study interactions between networks of neurons. This theoretical approach may help contextualize and understand the factors involved in regulating burst firing in populations and how it may modulate distinct aspects of behavior.Comment: 25 pages (including references and appendices); 12 figures uploaded as separate file