30,158 research outputs found
Human serum haptoglobin is toxic to Plasmodium falciparum in vitro
Innate immune responses are important in the control of malaria, particularly in those who have not yet mounted an effective adaptive response. Here we report that the human serum acute phase protein, haptoglobin is toxic to Plasmodium falciparum cultured in vitro. This effect is phenotype-dependent and occurs during the trophozoite phase of the asexual life cycle. We propose that the increased levels of haptoglobin seen in the acute phase response may be protective against malaria in humans
Voltage regulator/amplifier is self-regulated
Signal modulated, self-regulating voltage regulator/amplifier controls the output b-plus voltage in modulated regulator systems. It uses self-oscillation with feedback to a control circuit with a discontinuous amplitude action feedback loop
A Volume Clearing Algorithm for Muon Tomography
The primary objective is to enhance muon-tomographic image reconstruction
capability by providing distinctive information in terms of deciding on the
properties of regions or voxels within a probed volume "V" during any point of
scanning: threat type, non-threat type, or not-sufficient data. An algorithm
(MTclear) is being developed to ray-trace muon tracks and count how many
straight tracks are passing through a voxel. If a voxel "v" has sufficient
number of straight tracks (t), then "v" is a non-threat type voxel, unless
there are sufficient number of scattering points (p) in "v" that will make it a
threat-type voxel. The algorithm also keeps track of voxels for which not
enough information is known: where p and v both fall below their respective
threshold parameters. We present preliminary results showing how the algorithm
works on data collected with a Muon Tomography station based on gas electron
multipliers operated by our group. The MTclear algorithm provides more
comprehensive information to a human operator or to a decision algorithm than
that provided by conventional muon-tomographic reconstruction algorithms, in
terms of qualitatively determining the threat possibility from a probed volume.
This is quite important because only low numbers of cosmic ray source muons are
typically available in nature for tomography, while a quick determination of
threats is essential.Comment: 3 pages, 3 figures, submitted to conf. record of 2014 IEEE Nucl. Sci.
Symposium, Seattl
Computer program samples digital data for CRT display
High volume, multichannel data reduction computer program permits selection of the rates at which digital data is sampled. The program, written in FORTRAN 4 source language, also permits accessibility to the original mass of data
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The response of tropospheric circulation to perturbations in lower-stratospheric temperature
A multiple regression analysis of the NCEP-NCAR reanalysis dataset shows a response to increased solar activity of a weakening and poleward shift of the subtropical jets. This signal is separable from other influences, such as those of El Nino-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO), and is very similar to that seen in previous studies using global circulation models (GCMs) of the effects of an increase in solar spectral irradiance. The response to increased stratospheric (volcanic) aerosol is found in the data to be a weakening and equatorward shift of the jets. The GCM studies of the solar influence also showed an impact on tropospheric mean meridional circulation with a weakening and expansion of the tropical Hadley cells and a poleward shift of the Ferrel cells. To understand the mechanisms whereby the changes in solar irradiance affect tropospheric winds and circulation, experiments have been carried out with a simplified global circulation model. The results show that generic heating of the lower stratosphere tends to weaken the subtropical jets and the tropospheric mean meridional circulations. The positions of the jets, and the extent of the Hadley cells, respond to the distribution of the stratospheric heating, with low-latitude heating forcing them to move poleward, and high-latitude or latitudinally uniform heating forcing them equatorward. The patterns of response are similar to those that are found to be a result of the solar or volcanic influences, respectively, in the data analysis. This demonstrates that perturbations to the heat balance of the lower stratosphere, such as those brought about by solar or volcanic activity, can produce changes in the mean tropospheric circulation, even without any direct forcing below the tropopause
MEA/A-1 experiment 81F01 conducted on STS-7 flight, June 1983. Containerless processing of glass forming melts
The space processing of containerless, glassforming melts on board the space shuttle flight STS-7 is investigated. Objectives include; (1) obtain quantitative evidence for the supression of heterogeneous nucleation/crystallization, (2) study melt homogenization without gravity driven convection, (3) procedural development for bubble free, high purity homogeneous melts inmicro-g, (4) comparative analysis of melts on Earth and in micro g, and (5) assess the apparatus for processing multicomponent, glass forming melts in a low gravity environment
Containerless processing of glass forming melts: D-1, MEA/A-2 experiment 81F01 conducted on STS-61A flight, October 1985
Results of experiment 81F01, which was conducted in the Material Experiment Assembly MEA/A-2 on the D-1 Spacelab Mission (STS-61A), are presented. The general plan of the experiment was to heat, melt, and quench six spherical samples of different glass forming compositions while they were levitated in a single axis acoustic levitator furnace (SAAL). In addition, two non-melting sintered alumina samples were used to check the operational characteristics of the SAAL under reduced gravity conditions. Three of the eight samples were levitated between 1250 and 1500 C before the lack of coolant created an over-temperature condition that caused the SAAL to shut down prematurely. Two of the three samples processed were calcia-gallia-silica and soda-lime-silica glass forming compositions. Evidence of a two to three times increase in the tendency for glass formation was obtained for the calcia-gallia-silica. The final glass appeared reasonably homogeneous even though it was made from hot pressed powders containing deliberate heterogeneities. A photographic record was obtained of the microgravity sample processing sequences
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