7,211 research outputs found
Data base management system analysis and performance testing with respect to NASA requirements
Several candidate Data Base Management Systems (DBM's) that could support the NASA End-to-End Data System's Integrated Data Base Management System (IDBMS) Project, later rescoped and renamed the Packet Management System (PMS) were evaluated. The candidate DBMS systems which had to run on the Digital Equipment Corporation VAX 11/780 computer system were ORACLE, SEED and RIM. Oracle and RIM are both based on the relational data base model while SEED employs a CODASYL network approach. A single data base application which managed stratospheric temperature profiles was studied. The primary reasons for using this application were an insufficient volume of available PMS-like data, a mandate to use actual rather than simulated data, and the abundance of available temperature profile data
On Compact Routing for the Internet
While there exist compact routing schemes designed for grids, trees, and
Internet-like topologies that offer routing tables of sizes that scale
logarithmically with the network size, we demonstrate in this paper that in
view of recent results in compact routing research, such logarithmic scaling on
Internet-like topologies is fundamentally impossible in the presence of
topology dynamics or topology-independent (flat) addressing. We use analytic
arguments to show that the number of routing control messages per topology
change cannot scale better than linearly on Internet-like topologies. We also
employ simulations to confirm that logarithmic routing table size scaling gets
broken by topology-independent addressing, a cornerstone of popular
locator-identifier split proposals aiming at improving routing scaling in the
presence of network topology dynamics or host mobility. These pessimistic
findings lead us to the conclusion that a fundamental re-examination of
assumptions behind routing models and abstractions is needed in order to find a
routing architecture that would be able to scale ``indefinitely.''Comment: This is a significantly revised, journal version of cs/050802
Gas-Modified Electrospinning with a Portable Device
Project Objective
The objective of this work was to construct a miniaturized, portable electrospinning (ES) device for deposition on surfaces regardless of charge.
We hope this device can be used by doctors in rural areas to deliver drug delivery bandages.
Mathematical modeling was used to improve predictability of the completed portable ES device
Results of data base management system parameterized performance testing related to GSFC scientific applications
The results of a variety of tests designed to demonstrate and evaluate the performance of several commercially available data base management system (DBMS) products compatible with the Digital Equipment Corporation VAX 11/780 computer system are summarized. The tests were performed on the INGRES, ORACLE, and SEED DBMS products employing applications that were similar to scientific applications under development by NASA. The objectives of this testing included determining the strength and weaknesses of the candidate systems, performance trade-offs of various design alternatives and the impact of some installation and environmental (computer related) influences
Deposition of Drug-delivering Bandages via a Combined Electrostatic and Air-Driven Electrospinning Device
Electrospinning (ES) is an affordable manufacturing process to produce nanoscale, polymer fibers.
During ES, a high voltage differential is required to draw out polymer fibers from a polymer solution at a charged spinneret.
Fibers produced are then deposited onto an oppositely charged electrode.
ES typically requires large, immovable equipment and conductive surfaces for deposition of fibers.
Portability and on-demand ES of fiber mats onto non-conductive surfaces would enable use in re- mote locations with limited access to medicine
kt Effects in Direct-Photon Production
We discuss the phenomenology of initial-state parton-kt broadening in
direct-photon production and related processes in hadron collisions. After a
brief summary of the theoretical basis for a Gaussian-smearing approach, we
present a systematic study of recent results on fixed-target and collider
direct-photon production, using complementary data on diphoton and pion
production to provide empirical guidance on the required amount of kt
broadening. This approach provides a consistent description of the observed
pattern of deviation of next-to-leading order QCD calculations relative to the
direct-photon data, and accounts for the shape and normalization difference
between fixed-order perturbative calculations and the data. We also discuss the
uncertainties in this phenomenological approach, the implications of these
results on the extraction of the gluon distribution of the nucleon, and the
comparison of our findings to recent related work.Comment: LaTeX, uses revtex and epsf, 37 pages, 15 figure
Implications of Hadron Collider Observables on Parton Distribution Function Uncertainties
Standard parton distribution function sets do not have rigorously quantified
uncertainties. In recent years it has become apparent that these uncertainties
play an important role in the interpretation of hadron collider data. In this
paper, using the framework of statistical inference, we illustrate a technique
that can be used to efficiently propagate the uncertainties to new observables,
assess the compatibility of new data with an initial fit, and, in case the
compatibility is good, include the new data in the fit.Comment: 22 pages, 5 figure
Examination of direct-photon and pion production in proton-nucleon collisions
We present a study of inclusive direct-photon and pion production in hadronic
interactions, focusing on a comparison of the ratio of gamma/pi0 yields with
expectations from next-to-leading order perturbative QCD (NLO pQCD). We also
examine the impact of a phenomenological model involving k_T smearing (which
approximates effects of additional soft-gluon emission) on absolute predictions
for photon and pion production and their ratio.Comment: 20 pages, 12 figures. Minor changes in wording and in figure
GMO vs. Non-GMO: Comparing the Addictiveness of Corn in Rats
Genetically modified organisms (GMOs) refer to organisms whose DNA has been altered to produce a certain characteristic. GMOs account for a significant proportion of the crops produced in the United States. Specifically, GMO corn accounted for approximately 88% of all corn grown for human and animal consumption in the year 2012. Previously conducted studies have not uniformly demonstrated the safe use of GMO corn, and no studies have been conducted to analyze the addictiveness of GMO corn.
The idea of addiction refers to more than just a physical dependence, but to a psychological dependence on something as well. Addiction is sometimes accompanied by compulsive, uncontrollable behaviors that can interfere with other activities and which increase in intensity as there is an increase in access to the substance. Because food addiction is implicated in the prevalence of obesity and its associated pathologies, identifying addictiveness in GMO products may lead to changes in crop production, food production, and use.
This study will compare the addictive behaviors of rats who are fed GMO corn. The rats will be randomly divided into three groups. Each group will be fed a diet containing a portion of corn consisting of 0%, 50%, or 100% GMO corn, respectively, for 28 days. After the 28 day treatment period, the rats will be fed a corn-free diet for 10 days. The assessments will include both cage food consumption and body weight measurements taken during both the treatment and withdrawal periods, and behavioral symptoms observed in an open field test during the withdrawal period. The presence of withdrawal indicators will be scored for each rat. The scores will then be compared between the groups using a repeated measures ANOVA test
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