We propose a new method to measure the metallicity of Type Ia supernova progenitors using Mn and Cr lines in the X-ray spectra of young supernova remnants. We show that the Mn to Cr mass ratio in Type Ia supernova ejecta is tightly correlated with the initial metallicity of the progenitor, as determined by the neutron excess of the white dwarf material before thermonuclear runaway. We use this correlation, together with the flux of the Cr and Mn Kalpha X-ray lines in the Tycho supernova remnant recently detected by Suzaku (Tamagawa et al. 2008) to derive a metallicity of log(Z) = -1.32 (+0.67,-0.33) for the progenitor of this supernova, which corresponds to log(Z/Zsun)= 0.60 (+0.31,-0.60) according to the latest determination of the solar metallicity by Asplund et al. (2005). The uncertainty in the measurement is large, but metallicities much smaller than the solar value can be ...
2008-01-01
During searches for new optical Galactic supernova remnants (SNRs) in the high resolution, high sensitivity Anglo-Australian Observatory/United Kingdom Schmidt Telescope (AAO/UKST) HAlpha survey of the southern Galactic plane, we uncovered a variety of filamentary and more diffuse, extensive nebular structures in the vicinity of Wolf-Rayet (WR) star 48 (Theta Muscae), only some of which were previously recognised. We used the double-beam spectrograph of the Mount Stromlo and Siding Spring Observatory (MSSSO) 2.3-m to obtain low and mid resolution spectra of selected new filaments and structures in this region. Despite spectral similarities between the optical spectra of WR star shells and SNRs, a careful assessment of the new spectral and morphological evidence from our deep HAlpha imagery suggests that the putative shell of Theta Mus is not a WR shell at all, as has been commonly accepted, but is ...
2009-01-01
High Energy Neutrino Telescopes
This paper presents a review of the history, motivation and current status of high energy neutrino telescopes. Many years after these detectors were first conceived, the operation of kilometer-cubed scale detectors is finally on the horizon at both the South Pole and in the Mediterranean Sea. These new detectors will perhaps provide us the first view of high energy astrophysical objects with a new messenger particle and provide us with our first real glimpse of the distant universe at energies above those accessible by gamma-ray instruments. Some of the topics that can be addressed by these new instruments include the origin of cosmic rays, the nature of dark matter, and the mechanisms at work in high energy astrophysical objects such as gamma-ray bursts, active galactic nuclei, pulsar wind nebula and supernova remnants.
2008-01-01
We review X-ray plasma diagnostics based on the line ratios of He-like ions. Triplet/singlet line intensities can be used to determine electronic temperature and density, and were first developed for the study of the solar corona. Since the launches of the X-ray satellites Chandra and XMM-Newton, these diagnostics have been extended and used (from CV to Si XIII) for a wide variety of astrophysical plasmas such as stellar coronae, supernova remnants, solar system objects, active galactic nuclei, and X-ray binaries. Moreover, the intensities of He-like ions can be used to determine the ionization process(es) at work, as well as the distance between the X-ray plasma and the UV emission source for example in hot stars. In the near future thanks to the next generation of X-ray satellites (e.g., Astro-H and IXO), higher-Z He-like lines (e.g., iron) will be resolved, allowing plasmas with higher temperatures and densities to be ...
2011-01-01
In this work we develop a new propagation model for the Galactic cosmic rays based on the GALPROP code, including contributions from dark matter annihilation. The model predicts compatible Galactic diffuse $\\gamma$ ray spectra with EGRET data in all sky regions. It also gives consistent results of the diffuse $\\gamma$ ray longitude and latitude distributions. Further the results for B/C, $^{10}$Be/$^9$Be, proton, electron and antiproton spectra are also consistent with cosmic ray measurements. In the model we have taken a universal proton spectrum throughout the Galaxy without introducing large fluctuation for the proton energy loss is negligible. The dark matter annihilation signals are `boosted' after taking the contribution from subhalos into account. Another interesting feature of the model is that it gives better description of the diffuse $\\gamma$ rays when taking the source distribution compatible with supernova ...
2007-01-01
Electron acceleration in supernova remnants and diffuse gamma rays above 1 GeV
DEFF Research Database (Denmark)
The recently observed X-ray synchrotron emission from four supernova remnants (SNRs) has strengthened the evidence that cosmic-ray electrons are accelerated in SNRs. We show that if this is indeed the case, the local electron spectrum will be strongly time-dependent, at least above roughly 30 GeV. The time dependence stems from the Poisson fluctuations in the number of SNRs within a certain volume and within a certain time interval. As far as cosmic-ray electrons are concerned, the Galaxy looks like actively bubbling Swiss cheese rather than a steady, homogeneously filled system. Our finding has important consequences for studies of the Galactic diffuse gamma-ray emission, for which a strong excess over model predictions above 1 GeV has recently been reported. While these models relied on an electron injection spectrum with index 2.4 (chosen to fit the local electron flux up to 1 TeV), we show that an electron injection ...
1998-01-01
Cosmic-Ray Nuclei, Antiprotons and Gamma-rays in the Galaxy: a New Diffusion Model
We model the transport of cosmic ray nuclei in the Galaxy by means of a new numerical code. Differently from previous numerical models we account for a generic spatial distribution of the diffusion coefficient. We found that in the case of radially uniform diffusion, the main secondary/primary ratios (B/C, N/O and sub-Fe/Fe) and the modulated antiproton spectrum match consistently the available observations. Convection and re-acceleration do not seem to be required in the energy range we consider: $1 \\le E \\le 10^3$ GeV/nucleon. We generalize these results accounting for radial dependence of the diffusion coefficient, which is assumed to trace that of supernova remnants. While this does not affect the prediction of secondary/primary ratios, the simulated longitude profile of the diffuse $\\gamma$-ray emission is significantly different from the uniform case and may agree with EGRET measurements without invoking {\\it ad hoc} assumptions on ...
2008-01-01
ROSAT Status 130: Update on Wurzburg Conference - HEASARC - NASA
Aug 21, 1995... F.D. Two Southern Supernova Remnants Shibazaki, N. Effect of a Superfluid- Crust Coupling on the Neutron Star Evolution Siddiqui, ...
GALAXY EVOLUTION EXPLORER (GALEX) GUEST ... - GALEX - NASA
star evolution, globular cluster structure and evolution, massive stars, supernova remnants, reflection nebulae, interstellar dust, structure of the ISM, ...
An X-ray source population study of the Andromeda galaxy M 31
XMM-Newton EPIC observations reveal the population of X-ray sources of the bright Local Group spiral galaxy M 31, a low-star-formation-rate galaxy like the Milky Way, down to a 0.2-4.5 keV luminosity of 4.4E34 erg/s. With the help of X-ray hardness ratios and optical and radio information different source classes can be distinguished. The survey detected 856 sources in an area of 1.24 square degrees. Sources within M 31 are 44 supernova remnants (SNR) and candidates, 18 super-soft sources (SSS), 16 X-ray binaries (XRBs) and candidates, as well as 37 globular cluster sources (GlC) and candidates, i.e. most likely low mass XRBs within the GlC. 567 hard sources may either be XRBs or Crab-like SNRs in M 31 or background AGN. 22 sources are new SNR candidates in M 31 based on X-ray selection criteria. Time variability information can be used to improve the source classification. Two GlC sources show type I X-ray bursts as known from ...
2005-01-01
Bullets in a Core Collapse Supernova Remnant The Vela Remnant
We use two-dimensional hydrodynamical simulations to investigate the properties of dense ejecta clumps (bullets) in a core collapse supernova remnant, motivated by the observation of protrusions probably caused by clumps in the Vela supernova remnant. The ejecta, with an inner flat and an outer steep power law density distribution, were assumed to freely expand into an ambient medium with a constant density, $\\sim 0.1$ H atoms cm$^{-3}$ for the case of Vela. At an age of $10^4$ yr, the reverse shock front is expected to have moved back to the center of the remnant. Ejecta clumps with an initial density contrast $\\chi \\sim 100$ relative to their surroundings are found to be rapidly fragmented and decelerated. In order to cause a pronounced protrusion on the blast wave, as observed in the Vela remnant, $\\chi \\sim 1000$ may be required. In this case, the clump should be near the inflection point in ...
2001-01-01
Exploring the Physics of Type Ia Supernovae Through the X-ray Spectra of their Remnants
We present the results of an ongoing project to use the X-ray observations of Type Ia Supernova Remnants to constrain the physical processes involved in Type Ia Supernova explosions. We use the Tycho Supernova Remnant (SN 1572) as a benchmark case, comparing its observed spectrum with models for the X-ray emission from the shocked ejecta generated from different kinds of Type Ia explosions. Both the integrated spectrum of Tycho and the spatial distribution of the Fe and Si emission in the remnant are well reproduced by delayed detonation models with stratified ejecta. All the other Type Ia explosion models fail, including well-mixed deflagrations calculated in three dimensions.
2005-01-01
Antimatter production in supernova remnants
We calculate the energy spectra of cosmic rays (CR) and their secondaries produced in a supernova remnant (SNR), taking into account the time-dependence of the SNR shock. We model the trajectories of charged particles as a random walk with a prescribed diffusion coefficient, accelerating the particles at each shock crossing. Secondary production by CRs colliding with gas is included as a Monte Carlo process. We find that SNRs produce less antimatter than suggested previously: The positron/electron ratio and the antiproton/proton ratio are a few percent and few $\\times 10^{-5}$, respectively. Moreover, the obtained positron/electron ratio decreases with energy, while the antiproton/proton ratio rises at most by a factor of two above 10 GeV.
2011-01-01
Is the Supernova Remnant RX J1713.7-3946 a Hadronic Cosmic Ray Accelerator ?
The non-thermal supernova remnant RX J1713.7-3946 (G347.3-0.5) has recently been shown to be a site of cosmic ray (CR) electron acceleration to TeV energies (Muraishi et al. 2000). Here we present evidence that this remnant is also accelerating CR nuclei. Such nuclei can interact with ambient interstellar gas to produce high energy gamma-rays via the decay of neutral pions. We associate the unidentified EGRET GeV gamma- ray source 3EG J1714-3857 with a massive (~3*10 5 Mo) and dense (~500 nucleons cm -3) molecular cloud interacting with RX J1713.7-3946. Direct evidence for such interaction is provided by observations of the lowest two rotational transitions of CO in the cloud; as in other clear cases of interaction, the CO(J=2-1)/CO(J=1-0) ratio is significantly enhanced. Since the cloud is of low radio and X-ray brightness, CR electrons cannot be responsible for the bulk of its GeV emission there. A picture thus emerges where both electrons ...
2001-01-01
Integration and Testing of the Micro-X Rocket Payload
The Micro-X instrument is a rocket borne, X-ray imaging spectrometer planned for launch in October 2011. An array of 128 Transition Edge Sensors (TESs) on a 600 micron pitch will observe incoming photons in the 0.2-3 keV energy band with an energy resolution of 2-4 eV at 1 keV. X-rays will be focused onto the TES array by a conically approximated Wolter optic with an effective area of 300 cm^2 giving the instrument a field of view of 11.8 arcmin. This performance will constitute a substantial improvement over current non-dispersive detectors for X-ray spectroscopy of extended sources and will be the first demonstration of a TES-based microcalorimeter in space. The TESs will utilize the 50 mK stage of an Adiabatic Demagnetization Refrigerator (ADR) as a heat bath, and will be read out by a SQUID time division multiplexer. The first flight of the Micro-X instrument will observe the Puppis A supernova remnant. Future targets include the core of ...
2011-05-01
A Chandra Observation of Supernova Remnant G350.1-0.3 and Its Central Compact Object
We present a new Chandra observation of supernova remnant (SNR) G350.1-0.3. The high resolution X-ray data reveal previously unresolved filamentary structures and allow us to perform detailed spectroscopy in the diffuse regions of this SNR. Spectral analysis demonstrates that the region of brightest emission is dominated by hot, metal-rich ejecta while the ambient material along the perimeter of the ejecta region and throughout the remnant's western half is mostly low-temperature, shocked interstellar/circumstellar medium (ISM/CSM) with solar-type composition. The data reveal that the emission extends far to the west of the ejecta region and imply a lower limit of 6.6 pc on the diameter of the source (at a distance of 4.5 kpc). We show that G350.1-0.3 is likely in the free expansion (ejecta-dominated) stage and calculate an age of 600-1200 years. The derived relationship between the shock velocity and the electron/proton temperature ratio is ...
2011-01-01
Images of very high energy cosmic ray sources in the Galaxy: I. A source towards the galactic centre
Energy Technology Data Exchange (ETDEWEB)
Recent analyses of the anisotropy of cosmic rays at 10{sup 18} eV (the AGASA and SUGAR data) show significant excesses from regions close to the galactic centre and Cygnus. Our aim is to check whether such anisotropies can be caused by single sources of charged particles. We investigate propagation of protons in two models of the galactic regular magnetic field (with the irregular component included) assuming that the particles are injected by a short-lived discrete source lying in the direction of the galactic centre. We show that apart from a prompt image of the source, the regular magnetic field may cause delayed images at quite large angular distances from the actual source direction. The image is strongly dependent on the time elapsed after ejection of particles and it is also very sensitive to their energy. For the most favourable conditions for particle acceleration by a young pulsar, the ...
2002-08-01
International Nuclear Information System (INIS)
Rossi X-ray Timing Explorer (RXTE) observations of the bright supernova remnant Cas A have revealed a hard power law component above 10 keV in addition to two thermal components inferred from ASCA measurements of the many line centroids from low-Z elements. The power law can be shown to be consistent with synchrotron emission from radio to hard x-rays by electrons of up to 4 x 10"1"3 eV. Measurement of the 1157 keV line by CGRO from "4"4Sc in the chain of decay of "4"4Ti predicts that the two "4"4Ti lines at 68 and 78 keV should appear at the CGRO intensity. RXTE has placed upper limits on such lines that are marginally consistent with the CGRO measurement. Implications of these results on sites for cosmic ray acceleration and nucleosynthesis are discussed.
1999-01-01
On the evolution of supernova remnants: Pt. 2
International Nuclear Information System (INIS)
Supernova explosions within wind-driven bubbles are studied with 2D hydrodynamical calculations. Two different density distributions for the ejecta are considered: (i) a smooth, unfragmented power-law stratification, and (ii) a fragmented distribution. As in 1D models, the presence of the shell of interstellar swept-up matter causes the rapid evolution of the remnant to the radiative phase. The main 2D effects, for both fragmented and unfragmented ejecta, include: (i) substantial chaotic deviations from a purely radial flow in the remnant interior, (ii) efficient turbulent mixing between the ejecta and the shocked wind, resulting in homogenization of the former wind cavity, and (iii) severe distortion of the wind-driven shell by cooling and Rayleigh-Taylor instabilities. (author).
Magnetospheric particle acceleration and X-ray emission of pulsars
The available data on isolated X-ray pulsars, their wind nebulae, and the supernova remnants which are connected to some of these sources are analyzed. It is shown that electric fields of neutron stars tear off charged particles from the surface of neutron star and trigger the acceleration of particles. The charged particles are accelerated mainly in the field of magneto-dipole radiation wave. Power and energy spectra of the charged particles depend on the strength of the magneto-dipole radiation. Therefore, the X-ray radiation is strongly dependent on the rate of rotational energy loss and weakly dependent on the electric field intensity. Coulomb interaction between the charged particles is the main factor for the energy loss and the X-ray spectra of the charged particles.
2007-01-01
DETECTION OF AN X-RAY PULSATION FOR THE GAMMA-RAY PULSAR CENTERED IN CTA 1
International Nuclear Information System (INIS)
We report the detection of X-ray pulsations with a period of ?315.87 ms from the 2009 XMM-Newton observation for the radio-quiet ?-ray pulsar, LAT PSR J0007+7303, centered in the supernova remnant CTA 1. The detected pulsed period is consistent with the ?-ray periodicity at the same epoch found with the Fermi Gamma-ray Space Telescope. The broader sinusoidal structure in the folded light curve of the X-ray emission is dissimilar to that of the ?-ray emission, and the phase of the peak is about 0.5 shifting from the peak in the ?-ray bands, indicating that the main component of the X-rays originates from different sites of the pulsar. We conclude that the main component of the X-ray pulsation is contributed by the thermal emission from the neutron star. Although with a significantly different characteristic age, PSR J0007+7303 is similar to Geminga in emission properties of X-rays and ?-rays; this makes PSR J0007+7303 the second radio-quiet ...
2010-12-10
Binaries migrating in a gaseous disk: Where are the Galactic center binaries?
The massive stars in the Galactic center inner arcsecond share analogous properties with the so-called Hot Jupiters. Most of these young stars have highly eccentric orbits, and were probably not formed in-situ. It has been proposed that these stars acquired their current orbits from the tidal disruption of compact massive binaries scattered toward the proximity of the central supermassive black hole. Assuming a binary star formed in a thin gaseous disk beyond 0.1 pc from the central object, we investigate the relevance of disk-satellite interactions to harden the binding energy of the binary, and to drive its inward migration. A massive, equal-mass binary star is found to become more tightly wound as it migrates inwards toward the central black hole. The migration timescale is very similar to that of a single-star satellite of the same mass. The binary's hardening is caused by the formation of spiral tails lagging the stars inside the binary's ...
2010-01-01
THE CHEMICAL EVOLUTION OF THE URSA MINOR DWARF SPHEROIDAL GALAXY
International Nuclear Information System (INIS)
We present an abundance analysis based on high-resolution spectra of 10 stars selected to span the full range in metallicity in the Ursa Minor (UMi) dwarf spheroidal (dSph) galaxy. We find that [Fe/H] for the sample stars ranges from -1.35 to -3.10 dex. Combining our sample with previously published work for a total of 16 luminous UMi giants, we establish the trends of abundance ratios [X/Fe] as functions of [Fe/H] for 15 elements. In key cases, particularly for the #alpha#-elements, these trends resemble those for stars in the outer part of the Galactic halo, especially at the lowest metallicities probed. The neutron-capture elements show an r-process distribution over the full range of Fe metallicity reached in this dSph galaxy. This suggests that the duration of star formation in the UMi dSph was shorter than in other dSph galaxies. The derived ages for a larger sample of UMi stars with more uncertain metallicities also suggest a population dominated by ...
2010-08-10
In a recent survey of the stellar populations of LINERS and LINER/HII Transition Objects (TOs) we identified a numerous class of nuclei which stand out because of their conspicuous 10^8-9 yr populations. These objects were called ``Young-TOs'', since they all have TO-like emission line ratios. In this paper we investigate the radial variations of spectral properties in Low Luminosity AGN. Our analysis is based on high S/N, 3500-5500 A, long-slit spectra for 47 galaxies. The data probe distances of typically up to 850 pc from the nucleus with a resolution of ~ 100 pc and S/N ~ 30. Stellar population gradients are mapped by the radial profiles of absorption line equivalent widths and colours along the slit. These variations are further analyzed by means of a decomposition of each spectrum in terms of template galaxies representative of very young (<= 10^7 yr), intermediate age (10^8-9 yr) and old (10^10 yr) populations. Our main findings are: ...
2004-01-01
EVIDENCE FOR DELAYED MASSIVE STAR FORMATION IN THE M17 PROTO-OB ASSOCIATION
International Nuclear Information System (INIS)
Through analysis of archival images and photometry from the Spitzer GLIMPSE and MIPSGAL surveys combined with Two Micron All Sky Survey and MSX data, we have identified 488 candidate young stellar objects (YSOs) in the giant molecular cloud M17 SWex, which extends #approx#50 pc southwest from the prominent Galactic H II region M17. Our sample includes >200 YSOs with masses >3 M _s_u_n that will become B-type stars on the main sequence. Extrapolating over the stellar initial mass function (IMF), we find that M17 SWex contains >1.3 x 10"4 young stars, representing a proto-OB association. The YSO mass function is significantly steeper than the Salpeter IMF, and early O stars are conspicuously absent from M17 SWex. Assuming M17 SWex will form an OB association with a Salpeter IMF, these results reveal the combined effects of (1) more rapid circumstellar disk evolution in more massive YSOs and (2) delayed onset of ...
2010-05-10
Energy Technology Data Exchange (ETDEWEB)
The INTEGRAL/SPI spectrometer was designed to observe the sky in the energy band of 20 keV to 8 MeV. The specificity of instrument SPI rests on the excellent spectral resolution (2.3 keV with 1 MeV) of its detecting plan, composed of 19 cooled germanium crystals; covering an effective area of 508 cm{sup 2}. The use of a coded mask, located at 1.7 m above the detection plan ensures to it a resolving power of 2.5 degrees. The aim of this thesis, begun before the INTEGRAL launch, is made up of two parts. The first part relates to the analysis of the spectrometer calibration data. The objective was to measure and check the performances of the telescope, in particular to validate simulations of the INTEGRAL/SPI instrument response. This objective was successfully achieved. This analysis also highlights the presence of a significant instrumental background noise. Whereas, the second part concentrates on the data analysis of the Vela region observations. I have approached two astrophysical ...
2005-01-15
Solar neutrinos, solar flares, solar activity cycle and the proton decay
It is shown that there may be a correlation between the galactic cosmic rays and the solar neutrino
1985-01-01
Rates of galactic star formation
Energy Technology Data Exchange (ETDEWEB)
A remarkably simple argument successfully accounts for the rate of star formation in different galaxies. The snag is that the timescale is uncomfortably short.
1985-08-29
APOD: 2009 May 25 - Hubble Floats Free
Space Telescope is currently planned for launch in 2014. Tomorrow's picture: galactic whirlpool ...
2011-10-07
APOD: 2000 July 18 - A Russian Proton Rocket Launches Zvezda
is launched from the Baikonur Cosmodrome in Kazakstan. Tomorrow's picture: A Galactic Whirlpool ...
2011-10-07
Acquired extrahepatic portosystemic shunts in a young dog
UK PubMed Central (United Kingdom)
AbstractA young, male miniature poodle was presented with severe neurological problems. Laboratory tests and ultrasonograph examination were consistent with extrahepatic portosystemic...Full Text Available
2006-07-01
The Galactic Exoplanet Survey Telescope (GEST)
The Galactic Exoplanet Survey Telescope (GEST) will observe a 2 square degree field in the Galactic bulge to search for extra-solar planets using a gravitational lensing technique. This gravitational lensing technique is the only method employing currently available technology that can detect Earth-mass planets at high signal-to-noise, and can measure the frequency of terrestrial planets as a function of Galactic position. GEST's sensitivity extends down to the mass of Mars, and it can detect hundreds of terrestrial planets with semi-major axes ranging from 0.7 AU to infinity. GEST will be the first truly comprehensive survey of the Galaxy for planets like those in our own Solar System.
2002-01-01
APOD: October 19, 1997 - The Heart Of NGC 4261
creating such active galactic nuclei as quasars. Strangely, the center of this fiery whirlpool is offset from the exact center of the galaxy - for a reason that for now remains an...
2011-10-07
APOD: December 5, 1995 - The Swirling Center of NGC 4261
creating such active galactic nuclei as quasars. Strangely, the center of this fiery whirlpool is offset from the exact center of the galaxy - for a reason that for now remains an...
2011-10-07
Galactic deuterium abundance as a test of cosmological models
Energy Technology Data Exchange (ETDEWEB)
The problem on change of deuterium abundance in the process of galactic evolution (star evolution, supernova explosions, nucleosynthesis in supermassive objects) is considered. It is shown that the observable deuterium quantity in the interstellar medium must correspond to its cosmological abundance. This conclusion is independent of the rate of accretion of intergalactic gas by Galaxy. The effect of hypothetical pregalactic active objects on cosmological deuterium is small. It is poind out that observations of interstellar deuterium in absorbtion at lambda=91.6 cm are significant.
1982-02-01
Emission-Line versus Continuum Correlations in Active Galactic Nuclei
The Baldwin Effect, a negative correlation between emission-line equivalent width and luminosity in active galactic nuclei, is still of interest as a diagnostic of accretion physics nearly thirty years after its discovery. This review examines recent developments in the study of correlations between line and continuum emission in AGNs, as measured both in ensembles and in individual sources.
2006-01-01
Energy Technology Data Exchange (ETDEWEB)
A new era for the field of Galactic structure is about to be opened with the advent of wide-area digital sky surveys. In this article, the author reviews the status and prospects for research for 3 new ground-based surveys: the Sloan Digital Sky Survey (SDSS), the Deep Near-Infrared Survey of the Southern Sky (DENIS) and the Two Micron AU Sky Survey (2MASS). These surveys will permit detailed studies of Galactic structure and stellar populations in the Galaxy with unprecedented detail. Extracting the information, however, will be challenging.
1994-11-01
KINEMATICS AT THE EDGE OF THE GALACTIC BULGE: EVIDENCE FOR CYLINDRICAL ROTATION
International Nuclear Information System (INIS)
We present new results from BRAVA, a large-scale radial velocity survey of the Galactic bulge, using M giant stars selected from the Two Micron All Sky Survey catalog as targets for the Cerro Tololo Inter-American Observatory 4 m Hydra multi-object spectrograph. The purpose of this survey is to construct a new generation of self-consistent bar models that conform to these observations. We report the dynamics for fields at the edge of the Galactic bulge at latitudes b = -8 deg. and compare to the dynamics at b = -4 deg. We find that the rotation curve V(r) is the same at b = -8 deg. as at b = -4 deg. That is, the Galactic boxy bulge rotates cylindrically, as do boxy bulges of other galaxies. The summed line-of-sight velocity distribution at b = -8 deg. is Gaussian, and the binned longitude-velocity plot shows no evidence for either a (disk) population with cold dynamics or for a (classical bulge) population with hot ...
2009-09-10
UK PubMed Central (United Kingdom)
This research focuses on young Mexican American girls who are not formal gang members yet participate in street-based activities of male gangs and engage in risk behaviors. These females comprise...Full Text Available
2003-01-01
UK PubMed Central (United Kingdom)
This study sought to assess the association between traditional masculine gender role ideologies and sexual risk and intimate partner violence (IPV) perpetration behaviors in young men's heterosexual...Full Text Available
2006-07-01
... the nest with young when the female left (male meadow voles were in the nest with young too infrequently ... prairie voles, whereas the number of checks that male meadow voles were in the nest increased s...
Hereditary Connective Tissue Diseases in Young Adult Stroke: A Comprehensive Synthesis
UK PubMed Central (United Kingdom)
Though the genetic background of ischaemic and haemorrhagic stroke is often polygenetic or multifactorial, it can in some cases result from a monogenic disease, particularly in young adults. Besides...Full Text Available
Economic Factors and Relationship Quality Among Young Couples: Comparing Cohabitation and Marriage
UK PubMed Central (United Kingdom)
Are economic resources related to relationship quality among young couples, and to what extent does this vary by relationship type? To answer these questions, we estimated regression models...Full Text Available
2010-10-01
Influence of HNS on the Microstructure and Properties of Cast ...
... The ultimate compressive strength was measured, and values for Young's modulus were calculated from the linear portion of the test curve. ...
1981-04-01
On the radial distribution of gamma rays in the outer galaxy
International Nuclear Information System (INIS)
The authors describe a new method which makes it possible to determine the radial distribution of the diffuse component of galactic gamma rays outside the solar circle. They use the observation that a good correlation exists between gamma-ray intensities and total column densities of the local interstellar gas and that the fractional column density of H_2<0.1 HI outside the solar circle. Thus the gamma-ray intensities are shown to be proportional to N(HI). The authors use the kinematics of the HI to determine the distances from which various fractions of the emission originate in the second and third galactic quadrants. Preliminary results of our analysis show that a significant flux of gamma rays originates from distances as large as 18 kpc from the galactic centre. (Auth.).
1982-08-04
The possible physical linkage between galactic cosmic rays intensity and the Earth's cloud cover is discussed using the analysis of the first indirect aerosol effect (Twomey effect) and its experimental representation as the dependence of average cloud droplet effective radius on aerosol index characterizing the aerosol concentration in the atmospheric air column of unit section. It is shown that the basic kinetic equation of the Earth's climate energy-balance model is described by the bifurcation equation (with respect to the temperature of the Earth's surface) in the form of fold catastrophe with two governing parameters defining the variations of insolation and Earth's magnetic field (or galactic cosmic rays intensity in the atmosphere), respectively. The principle of hierarchical climatic models construction, which consists in the structural invariance of balance equations of these models evolving on the different time scales, is described. ...
2008-01-01
Extragalactic Planetary Nebulae: Observational Challenges & Future Prospects
The study of extragalactic planetary nebulae (EPN) is a rapidly expanding field. The advent of powerful new instrumentation such as the PN spectrograph has led to an avalanche of new EPN discoveries both within and between galaxies. We now have thousands of EPN detections in a heterogeneous selection of nearby galaxies and their local environments, dwarfing the combined galactic detection efforts of the last century. Key scientific motivations driving this rapid growth in EPN research and discovery have been the use of the PNLF as a standard candle, as dynamical tracers of their host galaxies and dark matter and as probes of Galactic evolution. This is coupled with the basic utility of PN as laboratories of nebula physics and the consequent comparison with theory where population differences, abundance variations and star formation history within and between stellar systems informs both stellar and galactic evolution. Here ...
2004-01-01
The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III
Energy Technology Data Exchange (ETDEWEB)
The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Ly{alpha} forest, and a radial velocity search for planets around {approx}8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes 5-band imaging of roughly 5200 deg{sup 2} in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg{sup 2}, or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and ...
2011-01-01
Probing active galactic nuclei with H2O megamasers.
UK PubMed Central (United Kingdom)
We describe the characteristics of the rapidly rotating molecular disk in the nucleus of the mildly active galaxy NGC4258. The morphology and kinematics of the disk are delineated by the point-like...Full Text Available
1995-12-05
Galactic open clusters are since long recognized as one of the best tools for investigating the radial distribution of iron and other metals. We employed FLAMES at VLT to collect UVES spectra of bright giant stars in a large sample of open clusters, spanning a wide range of Galactocentric distances, ages, and metallicities. We present here the results for four clusters: Berkeley 20 and Berkeley 29, the two most distant clusters in the sample; Collinder 261, the oldest and the one with the minimum Galactocentric distance; Melotte 66. Equivalent width analysis was carried out using the spectral code MOOG and Kurucz model atmospheres to derive abundances of Fe, Al, Mg, Si, Ca, Ti, Cr, Ni, Ba; non-LTE Na abundances were derived by direct line-profile fitting. We obtain subsolar metallicities for the two anticenter clusters Be 20 ([Fe/H]=-0.30, rms=0.02) and Be 29 ([Fe/H]=-0.31, rms=0.03), and for Mel 66 ([Fe/H]=-0.33, rms=0.03), located in the third ...
2008-01-01
Cold dark matter annihilations: A source of gamma rays and antiprotons
Energy Technology Data Exchange (ETDEWEB)
Massive particle candidates for dark matter provide a potentially observable signature by virtue of their annihilations in the galactic halo at a known but model-dependent rate. Possible signatures are described, including cosmic ray antiproton and gamma-ray production. (orig.).
1989-08-01
Theoretical investigation of the behavior of an acoustic metamaterial with extreme Young's modulus
British Library Electronic Table of Contents (United Kingdom)
A mechanical model with local resonators is proposed as an acoustic metamaterial that exhibits an unusual frequency-dependent effective stiffness. If treated as an equivalent elastic solid, its effective Young's modulus can become unbounded or vanishingly small at two respective frequencies. Moreover, in a certain frequency range, the effective Young's modulus would become negative, resulting in a band gap that coincides with this frequency range. The wave attenuation behavior and mechanism are studied through numerical simulations on the acoustic metamaterial model. The capability of the metamaterial to selectively block or filter unwanted waves is demonstrated by a numerical simulation example.
2011-01-01
The diagnosis of young-onset dementia
UK PubMed Central (United Kingdom)
A diagnosis of dementia is devastating at any age but diagnosis in younger patients presents a particular challenge. The differential diagnosis is broad as late presentation of metabolic disease...Full Text Available
2010-08-01
UK PubMed Central (United Kingdom)
For some neurotoxic chemicals, neurobehavioral effects are now considered to be among the most sensitive end points yet detected, particularly if exposures occur during critical windows of vulnerability....Full Text Available
1999-06-01
Is Maternal Marriage Beneficial for Low-Income Adolescents?
UK PubMed Central (United Kingdom)
The present study investigated the association of mothers’ marriage and changes in young adolescents’ cognitive and socioemotional development and changes in family processes....Full Text Available
2009-01-01
International Nuclear Information System (INIS)
Turkish English ... Authors Sahin, O. (Suleyman Demirel University, Department of Physics, Isparta (Turkey))
2007-08-28
If I Had - Acne As a Young Female
... VIDEO: FASDs Cause More Severe Behavioral Problems Than ADHD, Baking Soda May Slow Chronic Kidney Disease, Higher ...
Effect of Smoking Scenes in Films on Immediate Smoking
UK PubMed Central (United Kingdom)
BackgroundThe National Cancer Institute has concluded that exposure to smoking in movies causes adolescent smoking and there are similar results for young adults.Full Text Available
2010-04-01
Age Preservation of the Syntactic Processor in Production
UK PubMed Central (United Kingdom)
Two experiments are reported on the influence of cognitive aging on grammatical choice in language production. In both experiments, participants from two age-groups (young and old) produced...Full Text Available
2003-09-01
Satellite CMB anisotropy missions and new generation of balloon-borne and ground experiments, make use of complex multi-frequency instruments at the focus of a meter class telescope. Between 70 GHz and 300 GHz, where foreground contamination is minimum, it is extremely important to reach the best trade-off between the improvement of the angular resolution and the minimization of the straylight contamination mainly due to the Galactic emission. We focus here, as a working case, on the 30 and 100 GHz channels of the Planck Low Frequency Instrument (LFI). We evaluate the GSC introduced by the most relevant Galactic foreground components for a reference set of optical configurations. We show that it is possible to improve the angular resolution of 5-7% by keeping the overall GSC below the level of few microKelvin. A comparison between the level of straylight introduced by the different Galactic components for different beam ...
2003-01-01
We study the Sunyaev-Zel'dovich (SZ) effect potentially generated by relativistic electrons injected from dark matter (DM) annihilation or decay in the Galaxy, and check whether it could be observed by Planck or ALMA, or even imprint the current CMB data as e.g. the specific fluctuation excess claimed from an recent re-analysis of the WMAP-5 data. We focus on high-latitude regions to avoid contamination of the Galactic astrophysical electron foreground, and consider the annihilation or decay coming from the smooth DM halo as well as from subhalos, further extending our analysis to a generic modeling of spikes arising around intermediate-mass-black-holes (IMBHs). We show that all these dark Galactic components are unlikely to produce any observable SZ effect. For a self-annihilating DM particle of 10 GeV with canonical properties, the largest optical depth we find is $\\tau_e \\lesssim 10^{-7}$ for massive isolated subhalos hosting IMBHs. We ...
2010-01-01
Modeling the Galactic CV Distribution for the ChaMPlane Survey
For purposes of designing targeted cataclysmic variable (CV) detection surveys and interpreting results of other projects with many CV detections such as the ChaMPlane Survey, we have created a model of the CV distribution in the Galaxy. It is modeled as a warped, flared exponential disk with a gaussian vertical distribution. Extinction is based on a detailed Galactic dust and gas model. A luminosity function for CVs is also incorporated, based on a smoothed version of published data. We calculate predicted field detection rates as a function of the limiting magnitude expected for the detecting system (i.e. WIYN/Hydra or NOAO 4m/Mosaic). Monte-Carlo techniques are used to assess statistical fluctuations in these rates. We have created maps of the expected CV distribution for the full non-bulge Galactic plane (20 2007-01-01
Energy Technology Data Exchange (ETDEWEB)
Diffuse {gamma}-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of view and long observation time, the Milagro Gamma Ray Observatory is an ideal instrument for surveying large regions of the Northern Hemisphere sky and for detecting diffuse {gamma}-ray emission at very high energies. Here, the spatial distribution and the flux of the diffuse {gamma}-ray emission in the TeV energy range with a median energy of 15 TeV for Galactic longitudes between 30{sup o} and 110{sup o} and between 136{sup o} and 216{sup o} and for Galactic latitudes between -10{sup o} and 10{sup o} are determined. The measured fluxes are consistent with predictions of the GALPROP model everywhere except for the Cygnus region (l {element_of} [65{sup o}, 85{sup o}]). For the Cygnus region, the ...
2008-05-14
Two years of flight of the Pamela experiment: results and perspectives
PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antinuclei with a precision of the order of $10^{-8}$). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, $15^{th}$ 2006 in a $350\\times 600 km$ orbit with an inclination of 70 degrees. In this work we describe the scientific objectives and the performance of PAMELA in its first two years of operation. Data on protons of trapped, secondary and galactic nature - as well as measurements of the December $13^{th}$ 2006 Solar Particle Event - are also provided.
2008-01-01
Nuclear reaction rates and opacity in massive star evolution calculations
International Nuclear Information System (INIS)
Nuclear reaction rates and opacity are important parameters in stellar evolution. The input physics in a stellar evolution code determines the main theoretical characteristics of the stellar structure, evolution and nucleosynthesis of a star. For different input physics, in this work we calculate stellar evolution models of very massive first stars during the hydrogen and helium burning phases. We have considered 100 and 200M_sun galactic and pregalactic stars with metallicity Z = 10"-"6 and 10"9, respectively. The results show important differences from old to new formulations for the opacity and nuclear reaction rates, in particular the evolutionary tracks are significantly affected, that indicates the importance of using up to date and reliable input physics. The triple alpha reaction activates sooner for pregalactic than for galactic stars.
2010-07-01
Jets and accretion processes in Active Galactic Nuclei further clues
We present evidence in favour of a link between the luminosity radiatively dissipated in the central engine of radio-loud Active Galactic Nuclei and the kinetic power in their jets. This piece of evidence is based on the relation we find between the luminosity in broad emission lines and the kinetic power in pc-scale radio jets, for a sample of radio-loud quasars for which suitable data are available in the literature. We find that the ionizing luminosity and the kinetic one are of the same order of magnitude, suggesting that the processes responsible for them are somehow related. A strong magnetic field in equipartition with the radiation field could be responsible for regulating both processes. BL Lac objects seem to follow a similar behaviour, but with comparatively fainter broad line emission.
1996-01-01
Young Generation of OAO 'Mashinostroitelny Zavod' Specialists Trends and Prospects
Energy Technology Data Exchange (ETDEWEB)
The paper brings forth the information related to the youth organizations acting at the factory, their policies, provisions of youth incentives, intake of employees to the company, labor motivation. There is also the information on the events, which take place on site, on the arrangements of the young employees' leisure, as well as on the creative and productive potential of the factory. (author)
2008-07-01
Weight-control behaviors and subsequent weight change among adolescents and young adult females123
UK PubMed Central (United Kingdom)
Background: Little is known about the effectiveness of behavioral strategies to prevent long-term weight gain among adolescents and young adults.Objective: The objective...Full Text Available
2010-01-01
UK PubMed Central (United Kingdom)
BackgroundAs the promotion of alcohol and tobacco to young people through direct advertising has become increasingly restricted, there has been greater interest in whether images...Full Text Available
... Future Job Fund Scheme Goodwood Allotments Location: Goodwood Allotments Work undertaken by long-term unemployed young people under the Future Jobs Fund (FJF) transforms derelict allotments into a readily workable space for the local community. New Parks Skegness Ride Location: New Parks Youth Centre Youths from the New Parks Club for Young People engage with sustainable transport and develop teamwork skills via a team bike ride. ...
This paper presents new images and spectroscopy of NGC 34 (Mrk 938) obtained with the du Pont 2.5-m and Baade 6.5-m telescopes at Las Campanas, plus photometry of an HST archival V image. This Mv = -21.6 galaxy has often been classified as a Seyfert 2, yet recently published infrared spectra suggest a dominant central starburst. We find that the galaxy features a single nucleus, a main spheroid containing a blue central disk, and tidal tails indicative of two former disk galaxies. These galaxies appear to have completed merging. The remnant shows three clear optical signs that the merger was gas-rich ("wet") and accompanied by a starburst: (1) It sports a rich system of young star clusters, of which 87 have absolute magnitudes -10.0 > Mv > -15.4. Five clusters with available spectra have ages in the range 0.1-1.0 Gyr, photometric masses between 2x10^6 and 2x10^7 Msun, and are gravitationally bound young globulars. (2) The blue central ...
2007-01-01
Surface photometry and the structure of elliptical galaxies
International Nuclear Information System (INIS)
Surface photometry of bulges and elliptical galaxies is reviewed. The properties of cores and nuclei as revealed by improvements in seeing and the use of CCDs are examined, and newly discovered structural details such as dust, shells, and dynamical subsystems which show the importance of accretion events in galactic evolution are addressed. Improved constraints on galaxy formation resulting from better measurements of parameter scaling laws are discussed, and accurate measurements of departures from elliptical isophotes and of color gradients obtained with CCDs are considered.
Energy Technology Data Exchange (ETDEWEB)
A possibility of generating collimated beams of faster-than-light particles (tachyons) and using them for rocket propulsion is explored. The relativistic rocket equations are derived, and are solved for a single-stage rocket with constant mass flow rate, constant exhaust velocity and no coasting period. The features of these solutions for faster-than-light exhaust velocities are discussed. It is shown that a tachyon drive would not violate the first law of thermodynamics. However, as seen in the Galactic frame, it would violate the second law.
1989-07-01
Indirect Dark Matter Detection with Cosmic Antimatter
The indirect detection of particle dark matter (DM) is based on the search for anomalous components in cosmic rays (CRs) due to the annihilation of DM pairs in the galactic halo, on the top of the standard astrophysical production. These additional exotic components are potentially detectable at Earth as spectral distortions for the various cosmic radiations: $\\chi + \\chi \\to q \\bar{q}, W^+ W^-, ... \\to \\bar{p}, \\bar{D}, e^+ \\gamma and \
2010-01-01
Global effects of interactions on galaxy evolution
International Nuclear Information System (INIS)
Recent observations of the evolutionary properties of paired and interacting galaxies are reviewed, with special emphasis on their global emission properties and star formation rates. Data at several wavelengths provide strong confirmation of the hypothesis, proposed originally by Larson and Tinsley, that interactions trigger global bursts of star formation in galaxies. The nature and properties of the starbursts, and their overall role in galactic evolution are also discussed.
1990-11-01
Contribution of pulsars to the cosmic rays in the Galaxy
Energy Technology Data Exchange (ETDEWEB)
The contribution of pulsar accelerated nuclei to the cosmic rays inside the Galaxy is calculated assuming that a significant part of the pulsar rotational energy is lost on acceleration of iron nuclei extracted from the surface of the neutron star. Different models of the galactic pulsar population are discussed. It is shown that the best description of the observed cosmic ray spectrum and the mass composition between a few 10{sup 15} eV and a few 10{sup 18} eV is obtained for the model B of Lorimer et al. (1993)
2004-11-15
British Library Electronic Table of Contents (United Kingdom)
Participation in conventional politics, such as elections, membership of organizations and political parties, is relatively low among young adults of ethnic minority background. Instead, engagement seems to find its way through aesthetic and other expressive channels of influence drawing on new technologies, impulses from transnational youth culture traditions, and both street riots and less conflictual actions. The aim of this article is to grasp a potential social movement in the making, by exploring the processes of articulation through which young people from immigrant families in Norway express their political engagement. The phenomenon of articulation is understood as a process comprising three steps or modes: (i) becoming conscious; (ii) generating expressions and (iii) collective a...
2011-01-01
Management of young onset colorectal cancer: divergent practice in the East of England
British Library Electronic Table of Contents (United Kingdom)
Abstract Aim- According to the revised Bethesda Guidelines, colorectal cancer (CRC) occurring under age 50-years should be screened to exclude Lynch syndrome. However, in current practice in East Anglia, tumour screening is initiated only after genetics referral, reserved for those with a strong pedigree. This study aimed to determine how many patients with young-onset CRC undergo tumour screening in hospitals in East Anglia. Method- A retrospective case notes review over 5-years in four hospitals was undertaken to determine what proportion of those with young-onset CRC underwent referral for tumour screening and to assess local practices in terms of patient counselling and management. Results- One hundred and twenty-two patients were included. There was an average yearly caseload of 6-9 p...
2011-01-01
Effect of aging on learning new names and descriptions for objects
British Library Electronic Table of Contents (United Kingdom)
The present study consisted of two experiments to compare new word learning in healthy young (N = 11) and older (N = 17) adults within an explicit learning paradigm. Experiment 1 investigated the new name learning for familiar objects, while Experiment 2 investigated learning names and descriptions for unfamiliar objects. Participants attended five learning sessions over 5 consecutive days, during which they viewed objects with novel names with/without descriptions. The older adults were as accurate as the young adults when recalling and recognizing new names during the learning sessions. With respect to response times, the older adults were as rapid as the young adults at recognizing the new names for the familiar objects, but were slower during the follow-up sessions. The older adults we...
2011-01-01
British Library Electronic Table of Contents (United Kingdom)
Nitric oxide (NO) is a gas produced through the action of nitric oxide synthase that acts as a neurotransmitter in the central nervous system (CNS) of adult gastropod mollusks. There are no known reports of the presence of NOS-containing neurons and glial cells in young and adult Megalobulimus abbreviatus. Therefore, NADPH-d histochemistry was employed to map the nitrergic distribution in the CNS of young and adult snails in an attempt to identify any transient enzymatic activity in the developing CNS. Reaction was observed in neurons and fibers in all CNS ganglia of both age groups, but in the pedal and cerebral ganglia, positive neurons were more intense than in other ganglia, forming clusters symmetrically located in both paired ganglia. However, neuronal NADPH-d activity in the mesocer...
2010-01-01
UK PubMed Central (United Kingdom)
BackgroundModern metal-on-metal hip resurfacing implants are being increasingly used for young and active patients, although the long-term outcome and failure mechanisms of these...Full Text Available
2010-06-01
UK PubMed Central (United Kingdom)
Presented here is a case of a young woman, with an undiagnosed osteoid osteoma of the spine, which presented with painful scoliosis in adolescence and was treated by bracing until her accession to adulthood....Full Text Available
UK PubMed Central (United Kingdom)
AbstractThe structural integrity of striated muscle is determined by extra-sarcomere cytoskeleton that includes structures that connect the Z-disks and M-bands of a sarcomere to sarcomeres...Full Text Available
2010-02-03
The preparation of a `metal-free' nappy and its application to metabolic balances in children
UK PubMed Central (United Kingdom)
Disposable nappies (diapers) have been satisfactorily demineralized and used for the collection of excreta from infants and young children during mineral and trace metal balances. It was possible to...Full Text Available
1972-11-01
UK PubMed Central (United Kingdom)
PurposeDutasteride and finasteride are 5α-reductase inhibitors that dramatically decrease serum levels of dihydrotestosterone. Because androgens...Full Text Available
2008-06-01
The Aging Heart and Post-Infarction Left Ventricular Remodeling
UK PubMed Central (United Kingdom)
Aging is a risk factor for heart failure, which is a leading cause of death world-wide. Elderly patients are more likely than young patients to experience a myocardial infarction (MI) and are...Full Text Available
2010-12-28
Tandem repeats analysis for the high resolution phylogenetic analysis of Yersinia pestis
UK PubMed Central (United Kingdom)
BackgroundYersinia pestis, the agent of plague, is a young and highly monomorphic species. Three biovars, each one thought to be associated with the last three Y....Full Text Available
TSH Isoforms: About a Case of Hypothyroidism in a Down's Syndrome Young Adult
UK PubMed Central (United Kingdom)
Background. For unknown reasons, the prevalence of thyroid autoimmune disorders is higher in patients with Down's syndrome than in the general population. The present case strongly...Full Text Available
THE STRUCTURE AND FUNCTION OF CENTRIOLES AND THEIR SATELLITES IN THE JELLYFISH PHIALIDIUM GREGARIUM
UK PubMed Central (United Kingdom)
Testes of jellyfish Phialidium gregarium were fixed in 2 per cent OsO4 in Veronal-acetate buffer at pH 7.4. Thin sections showed that in young spermatids the spindle fibers...Full Text Available
1964-06-01
Suffering in silence: consequences of sexual violence within marriage among young women in Nepal
UK PubMed Central (United Kingdom)
BackgroundDespite the grave consequences of sexual violence, and it's persistence both within and outside marriages, this subject has received relatively little attention from researchers,...Full Text Available
UK PubMed Central (United Kingdom)
BackgroundIndia experienced a rapid economic boom between 1991 and 2007. However, this economic growth has not translated into improved nutritional status among young Indian children....Full Text Available
UK PubMed Central (United Kingdom)
Objective:This article examines relationships between reproductive onset and lifetime history of smoking, regular smoking, and nicotine dependence, and cannabis and other illicit...Full Text Available
2009-09-01
UK PubMed Central (United Kingdom)
BackgroundSeverely disabling chronic pain in the adult population is strongly associated with a range of negative health consequences for individuals and high health care costs,...Full Text Available
UK PubMed Central (United Kingdom)
This review presents a summary of existing knowledge regarding the impact of testicular cancer along four broad domains, including romantic and sexual relationships, body image, and fertility....Full Text Available
2010-08-01
Reliability and Validity of the Sexual Pressure Scale for Women-Revised
UK PubMed Central (United Kingdom)
Sexual pressure among young urban women represents adherence to gender stereotypical expectations to engage in sex. Revision of the original 5-factor Sexual Pressure Scale was undertaken in...Full Text Available
2009-02-01
Refilling of Embolized Vessels in Young Stems of Laurel. Do We Need a New Paradigm?1
UK PubMed Central (United Kingdom)
Recovery of hydraulic conductivity after the induction of embolisms was studied in woody stems of laurel (Laurus nobilis). Previous experiments confirming the recovery of hydraulic...Full Text Available
1999-05-01
Reduced thermal sensitivity and Nav1.8 and TRPV1 channel expression in sensory neurons of aged mice
UK PubMed Central (United Kingdom)
Sensory neurons in aging mammals undergo changes in anatomy, physiology and gene expression that correlate with reduced sensory perception. In this study we compared young and aged mice to identify...Full Text Available
2006-06-01
Physique and Serum Lipids of Young London Busmen in relation to Ischaemic Heart Disease
UK PubMed Central (United Kingdom)
Earlier studies of white London busmen revealed that the ischaemic heart disease experience of conductors is better than that of drivers. Various factors which might be related to this difference have...Full Text Available
1967-07-01
Pharmacologically Induced Hypogonadism and Sexual Function in Healthy Young Women and Men
UK PubMed Central (United Kingdom)
Studies fail to find uniform effects of age-related or induced hypogonadism on human sexual function. We examined the effects of induced hypogonadism on sexual function in healthy men and women...Full Text Available
2009-02-01
UK PubMed Central (United Kingdom)
Young men's errors in sexual perception have been linked to sexual coercion. The current investigation sought to explicate the perceptual and decisional sources of these social perception errors,...Full Text Available
2010-01-01
PREVENTING TOBACCO USE AMONG YOUNG PEOPLE
UK PubMed Central (United Kingdom)
Preventing tobacco use in youths may be an easier task than helping adults break the habit of smoking and overcome its ill effects. Using experimental procedures based on social work techniques,...Full Text Available
1986-01-01
UK PubMed Central (United Kingdom)
Background and purpose:The chicken anterior mesenteric artery contains an outer longitudinal smooth muscle layer, whose neural regulation remains to be elucidated. ATP evokes a depolarization...Full Text Available
2009-10-01
Observations of late-type young stars in the Rho Oph dark cloud
Energy Technology Data Exchange (ETDEWEB)
We present photoelectric BVRI photometry for 16 T Tau and related stars in the Rho Oph dark cloud, as well as vidicon spectroscopic observations for nine stars. The color excesses of these stars favor circumstellar dust shells as the source of the observed infrared excesses.
1980-04-01
Multiple mechanisms account for lower plasma iron in young copper deficient rats
UK PubMed Central (United Kingdom)
Copper deficiency lowers brain copper and iron during development. The reduced iron content could be due to hypoferremia. Experiments were conducted to evaluate plasma iron and “ferroxidase”...Full Text Available
2008-06-01
Multifocal papillary-cystic neoplasm of the pancreas.
UK PubMed Central (United Kingdom)
This case report describes the second known instance of a multifocal capillary pancreatic neoplasm. Both cases occurred in young African American females. A less-than-total pancreatectomy was performed...Full Text Available
2003-12-01
UK PubMed Central (United Kingdom)
The goal of this study was to determine if the exaggerated morphine-induced conditioned place preference (CPP) response seen in adult rats after preweanling methylphenidate exposure is unique...Full Text Available
2009-03-01
Memories of John N. Brady: scientist, mentor and friend
UK PubMed Central (United Kingdom)
Friends and colleagues remember John N. Brady, Ph.D., Chief of the Virus Tumor Biology Section of the Laboratory of Cellular Oncology, who died much too young at the age of 57 on April 27, 2009 of colon...Full Text Available
Lower extremity vascular stenting for a post-traumatic pseudoaneurysm in a young trauma patient
UK PubMed Central (United Kingdom)
Endovascular treatment of post-traumatic pseudoaneurysms has become a viable, less invasive option when compared to open repair. Due to the relative youth of this technology, studies have yet to be...Full Text Available
2011-04-01
Impact of Lifelong Sedentary Behavior on Mitochondrial Function of Mice Skeletal Muscle
UK PubMed Central (United Kingdom)
This study investigated the impact of lifelong sedentariness on skeletal muscle mass and mitochondrial function. Thirty C57BL/6 strain mice (2 months) were randomly divided into three groups (young-Y;...Full Text Available
2009-09-01
Hormone Receptor Status in Breast Cancer and its Relation to Age and Other Prognostic Factors
UK PubMed Central (United Kingdom)
Background:Increasing evidence shows the importance of young age, estrogen receptor (ER), progesterone receptor (PR) status, and HER-2 expression in patients with breast cancers.Patients...Full Text Available
Hardness, density, and shrinkage characteristics of silk-oak from ...
Sep 1, 2011 ... Title: Hardness, density, and shrinkage characteristics of silk-oak from Hawaii. Author: Youngs, R. L.. Date: 1964. Source: Research note FPL ...
Genomic Expression Libraries for the Identification of Cross-Reactive Orthopoxvirus Antigens
UK PubMed Central (United Kingdom)
Increasing numbers of human cowpox virus infections that are being observed and that particularly affect young non-vaccinated persons have renewed interest in this zoonotic disease. Usually causing...Full Text Available
UK PubMed Central (United Kingdom)
The discovery that aerobic exercise increases adult hippocampal neurogenesis and can enhance cognitive performance holds promise as a model for regenerative medicine. This study adds two new...Full Text Available
2009-10-01
UK PubMed Central (United Kingdom)
1. One hundred and thirty-two antidromically identified paraventricular (PV) and supraoptic (SO) neurones were studied during milk ejection evoked by the suckling of the young, in thirty-four lactating...Full Text Available
1975-09-01
Ewing's sarcoma: a neuroectodermal tumor of the chest wall
International Nuclear Information System (INIS)
Ewing's sarcoma is the second most common malignant bone tumor in children and young adults. It is most prevalent between the ages of 10 and 15 years. There are present two cases of Ewing's sarcoma of the chest wall. The clinical, radiological and pathological features are described and the therapeutic options are discussed. (Author)
Evidence That Two Major Replicons Comprise the Genome of Staphylococcus Aureus.
In Staphylococcus aureus, a pronounced shift in position of the acriflavin resistance locus was observed when gene order was determined by marker frequency analysis of cells of various ages. In young cells (2-hour culture), acriflavin resistance was mappe...
1967-01-01
Epidemiology of underweight and overweight-obesity among term pregnant Sudanese women
UK PubMed Central (United Kingdom)
BackgroundThe increasing prevalence of obesity in young women is a major public health concern. Few data are available concerning the epidemiology of malnutrition especially obesity...Full Text Available
Effect of a Longitudinally Applied Voltage Upon the Growth of Zea mays Seedlings 1
UK PubMed Central (United Kingdom)
The electrical parameters that affect young seedling growth were investigated. Voltages ranging from 5 to 40 volts were applied longitudinally along the mesocotyl region of 4-day old Zea mays...Full Text Available
1988-08-01
EFFECT OF AGE ON THE ROLE OF RHO-KINASE IN SHORT TERM PARTIAL BLADDER OUTLET OBSTRUCTION
UK PubMed Central (United Kingdom)
ObjectivesWe examined the expression of Rho Kinase (ROK) isoforms in young and old rabbit’s detrusor smooth muscles (SM) during the progression of short term...Full Text Available
2008-03-01
EF Cha: Warm Dust Orbiting a Nearby 10 Myr Old Star
Most Vega-like stars have far-infrared excess (60micron or longward in IRAS, ISO, or Spitzer MIPS bands) and contain cold dust (~ 4% of the stars in nearby young stellar associations.
2007-01-01
UK PubMed Central (United Kingdom)
BackgroundWebsites of many rogue sellers of medications are accessible through links in email spam messages or via web search engines. This study examined...Full Text Available
Current Therapeutic Approaches in Metastatic and Recurrent Ewing Sarcoma
UK PubMed Central (United Kingdom)
Ewing sarcoma (ES) is the second most common type of primary bone malignancy in children and young adults. Survival rates for localized ES have improved to upwards of 70% with aggressive chemotherapy...Full Text Available
2011-01-01
Copy Number Alterations and Methylation in Ewing's Sarcoma
UK PubMed Central (United Kingdom)
Ewing's sarcoma is the second most common bone malignancy affecting children and young adults. The prognosis is especially poor in metastatic or relapsed disease. The cell of origin remains elusive,...Full Text Available
2011-01-01
UK PubMed Central (United Kingdom)
Schwannomas are rare mesenchymal tumors of the gastrointestinal tract. Occurrence of these tumors is more common in the stomach than in the large intestine. These tumors usually present as polypoidal...Full Text Available
2011-01-01
Cancer in young people in the north of England, 1968-85: analysis by census wards.
UK PubMed Central (United Kingdom)
OBJECTIVE--To determine whether the seeming excess of childhood leukaemia and lymphoma identified in Seascale, Cumbria, UK, remains unusual when put into a wider context. DESIGN--Analysis of cancer...Full Text Available
1993-04-01
Branch morphology in young poplar clones on floodplain sites in ...
Sep 28, 2011 ... Description: Four Populus clones were grown in central Missouri for 2 years at 1 x 1 m spacing to study total biomass production on floodplain ...
Biogeography of Tick-Borne Bhanja Virus (Bunyaviridae) in Europe
UK PubMed Central (United Kingdom)
Bhanja virus (BHAV) is pathogenic for young domestic ruminants and also for humans, causing fever and affections of the central nervous system. This generally neglected arbovirus of the family Bunyaviridae...Full Text Available
2009-01-01
UK PubMed Central (United Kingdom)
BackgroundIn Germany, there is a shortage of young physicians in several specialties, the situation of general practitioners (GP) being especially precarious. The factors influencing...Full Text Available
Automatic evaluation of body-related words among young women: an experimental study
UK PubMed Central (United Kingdom)
BackgroundPrevious research has demonstrated that exposure to images depicting the thin female ideal has negative effects on some females' levels of body dissatisfaction. Much of...Full Text Available
UK PubMed Central (United Kingdom)
Solid-pseudopapillary tumor (SPT) is a rare neoplasm of the pancreas that usually occurs in young females. It is generally considered a low-grade malignant tumor that can remain asymptomatic for several...Full Text Available
2008-02-14
UK PubMed Central (United Kingdom)
Neurons are born throughout adulthood in the hippocampus and show enhanced plasticity compared to mature neurons. However, there are conflicting reports on whether or not young neurons contribute...Full Text Available
2009-11-18
UK PubMed Central (United Kingdom)
BackgroundWith rates of childhood obesity increasing, physical activity (PA) promotion especially in young children has assumed greater importance. Given the limited effectiveness...Full Text Available
Neutrinos produced by nuclei injected by young pulsars inside compact massive binaries
Energy Technology Data Exchange (ETDEWEB)
We consider propagation of relativistic heavy nuclei injected by a young pulsar into the radiation field of a massive companion. If the binary system (BS) is compact enough, then the nuclei suffer multiple photodisintegrations in collisions with thermal photons coming from the massive star (MS). Due to the propagation effects of charged particles in the magnetic field of the MS some hadrons can impinge onto the MS surface at large angles. We calculate the fluxes of produced neutrinos as a function of the viewing angle measured from the plane of the BS. It is found that significant fluxes of neutrinos should be also expected in the case of non-eclipsing BSs.
2005-06-15
Depression among Alumni of Foster Care: Decreasing Rates through Improvement of Experiences in Care
The Northwest Foster Care Alumni Study examined the relation between experiences in foster care and depression among young adults who spent at least a year in foster care as adolescents. Results indicate that preparation for leaving foster care, nurturing supports from the foster family, school stability, access to tutoring, access to therapeutic service and support, and a shorter and more stable placement history were associated with a lower probability of depression in young adulthood. Results provide evidence that suggest ways to improve practice to decrease rates of depression among alumni of care. (Contains 2 tables.)
2008-12-01
A Virtual Young's Double Slit Experiment for Hard X-ray Photons
We have implemented a virtual Young's double slit experiment for hard X-ray photons with micro-fabricated bi-prisms. We observe fringe patterns with a scintillator, and quantify interferograms by detecting X-ray fluorescence from a scanned 30nm Cr metal film. The observed intensities are best modeled with a near-field, Fresnel analysis. The maximum fringe number in the overlap region is proportional to the ratio of real to imaginary parts refractive index of the prism material. The horizontal and vertical transverse coherence lengths at beamline APS 8-ID are measured.
2009-01-01
International Nuclear Information System (INIS)
We report the discovery of an active galactic nucleus (AGN) pair in the interacting galaxy system IRAS 20210+1121 at z = 0.056. An XMM-Newton observation reveals the presence of an obscured (N _H #approx# 5 x 10"2"3 cm"-"2), Seyfert-like (L _2_-_1_0_k_e_V = 4.7 x 10"4"2 erg s"-"1) nucleus in the northern galaxy, which lacks unambiguous optical AGN signatures. Our spectral analysis also provides strong evidence that the IR-luminous southern galaxy hosts a Type 2 quasar embedded in a bright starburst emission. In particular, the X-ray primary continuum from the nucleus appears totally depressed in the XMM-Newton band as expected in the case of a Compton-thick absorber, and only the emission produced by Compton scattering ('reflection') of the continuum from circumnuclear matter is seen. As such, IRAS 20210+1121 seems to provide an excellent opportunity to witness a key, early phase in the quasar evolution predicted by the theoretical models of quasar activation by ...
2010-10-20
The Galactic Center Region Gamma Ray Excess from A Supersymmetric Leptophilic Higgs Model
In a recent paper by Hooper and Goodenough, data from the Fermi Gamma Ray Telescope was analyzed and an excess of gamma rays was found in the emission spectrum from the Galactic Center Region. Hooper and Goodenough show that the excess can be well explained by 7-10 GeV annihilating dark matter with a power law density profile if the dark matter annihilates predominantly to tau pairs. In this paper we present such a dark matter model by extending the MSSM to include four Higgs doublets and one scalar singlet. A Z2 symmetry is imposed that enforces a Yukawa structure so that the up quarks, down quarks, and leptons each receive mass from a distinct doublet. This leads to an enhanced coupling of scalars to leptons and allows the model to naturally achieve the required phenomenology in order to explain the gamma ray excess. Our model yields the correct dark matter thermal relic density and avoids collider bounds from measurements of the Z width as well as direct ...
2011-01-01
We study the sensitivity to neutrino masses of a Galactic supernova neutrino signal as could be measured with the detectors presently in operation and with future large volume water \\v{C}erencov and scintillator detectors. The analysis uses the full statistics of neutrino events. The method proposed uses the principles of Bayesian inference reasoning and has shown a remarkably independence of astrophysical assumptions. We show that, after accounting for the uncertainties in the detailed astrophysical description of the neutrino signal and taking into account the effects of neutrino oscillations in the supernova mantle, detectors presently in operation can have enough sensitivity to reveal a neutrino mass (or to set upper limits) at the level of 1 eV. This is sensibly better than present results from tritium $\\beta$-decay experiments, competitive with the most conservative limits from neutrinoless double $\\beta$-decay and less precise but remarkably less ...
2005-01-01
Statistical studies of Galactic open clusters I. Structural and basic astrophysical parameters
Context. Study of open clusters is important not only for learning properties of these objects but also for understanding the process of formation and evolution of stars and the Milky Way. Aims. The paper contains determination of the global (geometrical and physical) characteristics of a large sample of Galactic open clusters from homogeneous near-infrared photometric data and analysis of mutual relations between those characteristics. Methods. The near-infrared JHK photometric data from the 2-Micron All Sky Survey were used to determine new coordinates of the centres, angular sizes and radial density profiles of 849 open clusters in the MilkyWay. Additionally, for 754 of these clusters age, reddening, distance and linear sizes were also derived. The sample contains 140 open clusters which have not been studied before. Results. The analysed sample contains open clusters with ages in the range from 7 Myr to 10 Gyr. The majority of these clusters are located up to 3 ...
2010-01-01
RESOLVING DOPPLER-FACTOR CRISIS IN ACTIVE GALACTIC NUCLEI: NON-STEADY MAGNETIZED OUTFLOWS
International Nuclear Information System (INIS)
Magnetically driven non-stationary acceleration of jets in active galactic nuclei results in the leading parts of the flow being accelerated to much higher Lorentz factors than in the case of steady-state acceleration with the same parameters. The higher Doppler-boosted parts of the flow may dominate the high-energy emission of blazar jets. We suggest that highly variable GeV and TeV emission in blazars is produced by the faster moving leading edges of highly magnetized non-stationary ejection blobs, while the radio data trace the slower-moving bulk flow. Thus, the radio and gamma-ray emission regions have different, but correlated, Doppler factors. High-energy emission is generated, typically within the optically thick core, in the outer parts of the broad-line emission region, avoiding the radiative drag on the faster parts of the flow. The radio emission should correlate with the gamma-ray emission, delayed with frequency-dependent time lag of the order of weeks ...
2010-10-10
Measurement of redshifted 21-cm emission from neutral hydrogen promises to be the most effective method for studying the reionisation history of hydrogen and, indirectly, the first galaxies. These studies will be limited not by raw sensitivity to the signal, but rather, by bright foreground radiation from Galactic and extragalactic radio sources and the Galactic continuum. In addition, leakage due to gain errors and non-ideal feeds conspire to further contaminate low-frequency radio obsevations. This leakage leads to a portion of the complex linear polarisation signal finding its way into Stokes I, and inhibits the detection of the non-polarised cosmological signal from the epoch of reionisation. In this work, we show that rotation measure synthesis can be used to recover the signature of cosmic hydrogen reionisation in the presence of contamination by polarised foregrounds. To achieve this, we apply the rotation measure synthesis technique to ...
2010-01-01
High Angular Resolution Imaging Spectroscopy of the Galactic Ultra-Compact HII Region K3-50A
Gemini North adaptive optics imaging spectroscopy is presented for the Galactic ultra-compact HII (UCHII) region K3-50A. Data were obtained in the K-band using the Near-infrared Integral Field Spectrograph (NIFS) behind the facility adaptive optics module ALTAIR in natural guide star mode. The NIFS data cube reveals a complex spatial morphology across the 0.1 pc scale of the 3'' UCHII region. Comparison of the nebular emission to Cloudy ionization models shows that the central source must have an effective temperature between about 37000 K and 45000 K with preferred values near 40000 K. Evidence is presented for sharp density variations in the nebula which are interpreted as a clearing of material nearest the central source. High excitation lines of FeIII and SeIV show that the ionization of the nebula clearly changes with distance from the central source. A double lobed kinematic signature (+/- 25 kms) is evident in the Br gamma line map which may be related to ...
2009-01-01
Baryonic Collapse within Dark Matter Halos and the Formation of Gaseous Galactic Disks
This paper constructs an analytic framework for calculating the assembly of galactic disks from the collapse of gas within dark matter halos, with the goal of determining the surface density profiles. Gas parcels (baryons) fall through the potentials of dark matter halos on nearly ballistic, zero energy orbits and collect in a rotating disk. The dark matter halos have a nearly universal form, as determined previously through numerical simulations. The calculation is first carried out for a variety of pre-collapse mass distributions and rotation profiles, including polytropic spheres in hydrostatic equilibrium with the halo potential. The resulting disk surface density profiles have nearly power-law forms, with well-defined edges. This idealized scenario is generalized to include non-spherical starting states and multiple accretion events (due to gas being added to the halo via merger events). This latter complication is explored in detail and considers a log-normal ...
2006-01-01
Antideuteron fluxes from dark matter annihilation in diffusion models
Antideuterons are among the most promising galactic cosmic ray-related targets for dark matter indirect detection. Currently only upper limits exist on the flux, but the development of new experiments, such as GAPS and AMS-02, provides exciting perspectives for a positive measurement in the near future. In this Paper, we present a novel and updated calculation of both the secondary and primary antideuteron fluxes. We employ a two-zone diffusion model which successfully reproduces cosmic-ray nuclear data and the observed antiproton flux. We review the nuclear and astrophysical uncertainties and provide an up to date secondary (i.e. background) antideuteron flux. The primary (i.e. signal) contribution is calculated for generic WIMPs annihilating in the galactic halo: we explicitly consider and quantify the various sources of uncertainty in the theoretical evaluations. Propagation uncertainties, as is the case of antiprotons, are sizeable. ...
2008-01-01
A Remarkable Low-Mass X-ray Binary within 0.1 pc of the Galactic Center
Recent X-ray and radio observations have identified a transient low-mass X-ray binary (LMXB) located only 0.1 pc in projection from the Galactic center, CXOGC J174540.0-290031. In this paper, we report the detailed analysis of X-ray and infrared observations of the transient and its surroundings. Chandra bservations detect the source at a flux of F_X = 2e-12 erg cm^-2 s^-1 (2-8 keV). After accounting for absorption both in the interstellar medium and in material local to the source, the implied luminosity of the source is only L_X = 4e34 erg/s (2-8 keV; D=8 kpc). However, the diffuse X-ray emission near the source also brightened by a factor of 2. The enhanced diffuse X-ray emission lies on top of a known ridge of dust and ionized gas that is visible infrared images. We interpret the X-ray emission as scattered flux from the outburst, and determine that the peak luminosity of CXOGC J174540.0-290031 was >2e36 erg/s. We suggest that the relatively small observed ...
2005-01-01
4U 1907+09: a HMXB running away from the Galactic plane
We report the discovery of a bow shock around the high-mass X-ray binary (HMXB) 4U 1907+09 using the Spitzer Space Telescope 24 $\\mu$m data (after Vela X-1 the second example of bow shocks associated with HMXBs). The detection of the bow shock implies that 4U 1907+09 is moving through the space with a high (supersonic) peculiar velocity. To confirm the runaway nature of 4U 1907+09, we measured its proper motion, which for an adopted distance to the system of 4 kpc corresponds to a peculiar transverse velocity of $\\simeq 160 \\pm 115$ km/s, meaning that 4U 1907+09 is indeed a runaway system and supporting the general belief that most of HMXBs possess high space velocities. The direction of motion of 4U 1907+09 inferred from the proper motion measurement is consistent with the orientation of the symmetry axis of the bow shock, and shows that the HMXB is running away from the Galactic plane. We also present the Spitzer images of the bow shock around Vela X-1 (a ...
2011-01-01
Sunyaev-Zel'dovich Effects from Quasars Shining in Galaxies and Groups
The energy fed by active galactic nuclei to the surrounding diffuse baryons changes the latter's amount, temperature, and distribution; so in groups and in member galaxies it affects the X-ray luminosity and also the Sunyaev-Zel'dovich effect. Here we compute how the latter is enhanced by the transient blastwave driven by a shining quasar, and is depressed when the equilibrium is recovered with a depleted density. We constrain such depressions and enhancements with the masses of relic black holes in galaxies and the X-ray luminosities in groups. We discuss how all these linked observables can tell the quasar contribution to the thermal history of the baryons pervading galaxies and groups.
2003-01-01
SKA in VLBI Impact on Studies of Small Scale Structures in Active Galactic Nuclei
We discuss the advantages which the next generation interferometer SKA (the Square Kilometer Array) will bring for Very Long Baseline Interferometry (VLBI) at centimeter wavelengths. With a sensitivity to micro-Jy level flux density, a brightness temperature limit of about 10.000 K, and an expected dynamic range in future VLBI maps of better than 1.000.000, the impact of SKA on the research of compact extragalactic radio sources and their energetic jets will be very strong. We discuss some consequences, including a possible combination of SKA with future space VLBI missions.
1999-01-01
International Nuclear Information System (INIS)
The mass distribution of the Sombrero Galaxy, NGC 4594, is calculated in order to investigate the suspicion that the rotational velocity of the galactic gas does not measure the circular velocity in the galaxy. It is shown that the H II rotation velocities are much less than circular in the central 35 arcsec of the galaxy, and that the suspicion is correct. Thus, the H II rotation velocities cannot be used to measure the mass distribution. The absorption-line rotation curve is used to derive the mass distribution, and it is found that the M/L ratio is nearly constant. It is concluded that the visible matter is self-gravitating at least in the central 180 arcsec. 44 references.
Magnetic braking of collapsing interstellar clouds
International Nuclear Information System (INIS)
The purpose of this investigation is to show that resource to anisotropic compression along a magnetic field is not a necessary condition for star formation within large collapsing interstellar gas clouds. Although such a scenario would certainly eliminate the magnetic field and angular momentum problems associated with isotropically collapsing clouds, it is believed there is sufficient observational theoretical evidence to warrant the present study of magnetically braked, isotropically collapsing gas clouds. It is not attempted to disprove the hypothesis of anisotropic compression, but to offer instead, a reasonable alternative. Angular momentum transfer from magnetically braked, cool interstellar gas clouds of 10"2, 10"3 and 10"4 times the mass of the sun is examined. Magnetic torques acting on a contracting, rotating cloud, permeated by a frozen-in magnetic field coupling the cloud to the galactic field of the surrounding interstellar medium, produce kinks in ...
Young Cypriots' perspectives of the symbolic values of smoking
British Library Electronic Table of Contents (United Kingdom)
This paper reports the findings of a study that explores the perspectives of 25 young Cypriots regarding the symbolic values of smoking with respect to their everyday lived experiences. This study was motivated by recognising the high levels of smoking prevalence among adolescents in Cyprus and the absence of published research 'recording' their own versions of reality about smoking. Data for the study were generated from one-to-one qualitative interviews which encouraged the participants to articulate the symbolic value of smoking in their day-to-day experiences. The analysis focuses first, on the content of the embedded symbolic values of smoking (e.g. the quality of being 'cool') and second on the role of these values (e.g. used in projecting an image) in their everyday lives. A central...
2010-01-01
British Library Electronic Table of Contents (United Kingdom)
Purpose Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. Design Optical radiation measurement, analysis, and perspective. Methods Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. Results Crystalline lens UV-B retinal protection is deficient in children and young adults, incre...
2010-01-01
The influence of normal human ageing on automatic movements
British Library Electronic Table of Contents (United Kingdom)
There is evidence that aged normal subjects have more difficulty in achieving automaticity than young subjects. The underlying central neural mechanism for this phenomenon is unclear. In the present study, functional magnetic resonance imaging (fMRI) was used to investigate the effect of normal ageing on automaticity. Aged healthy subjects were asked to practice self-initiated, self-paced, memorized sequential finger movements with different complexity until they could perform the tasks automatically. Automaticity was evaluated by having subjects perform a secondary task simultaneously with the sequential movements. Although it took more time, most aged subjects eventually performed the tasks automatically at the same level as the young subjects. Functional MRI results showed that, for bot...
2005-01-01
British Library Electronic Table of Contents (United Kingdom)
Bisphenol-A (BPA) is one of the most common environmental endocrine disrupters and has a wide range of effects on central nervous system. Adolescence is another important developmental period besides the early critical prenatal and neonatal periods. In the present study, we exposed mice to BPA (40, 400 mg/kg/d) between adolescence and young adulthood for 8 weeks and investigated its effects on the non-reproductive behaviors. In open field tests, rearing and grooming sex differences were abolished by BPA exposure. In the elevated plus maze test, the number of open arm entries, the time spent in open arms, and the number of unprotected head dips in the center area were reduced in males but increased in females by BPA at 40 or 400 mg/kg/d, thus eliminating or reversing sex differences in thes...
2011-01-01
Environmental Research Database
ObjectivesThe International Network for Young Scientists is holding a China:UK workshop in Shanghai in December. It will focus specifically on Renewable Energy. Profs Wallace and Infield have been invited to be the UK academic partners. Dr. Luo Yong Hao, Deputy Director of Institute for Thermal Engineering at Shanghai Jiao Tong University is the lead Chinese academic partner. British Council Shanghai are the co-ordinators of the event and have obtained some limited funding to cover the costs.. ~%~~%~T [continued...]DescriptionReseachers are being brought together at a China:UK Renewable Energy Research Workshop. They will define and initiate joint research and staff/student exchanges between Chinese and UK universities to advance renewable energy and related research to meet the energy needs of both China and the UK.~%~
2007-01-07
British Library Electronic Table of Contents (United Kingdom)
Effect of oil palm empty fruit bunch (OPEFB) fiber and poly(methyl acrylate) grafted OPEFB on several mechanical properties of poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blends using HAKEE Rheomixer at the rotor speed of 50 rpm, mixing temperature 150degreeC, and mixing period of 20 min. The fiber loadings were varied from 0 to 30% and the effect of fiber content in the composites on their ultimate tensile strength (UTS), Youngs modulus, elongation at break, flexural modulus, hardness, and impact strength were determined. An increasing trend was observed in the Youngs modulus, flexural modulus, and hardness with the addition of grafted and ungrafted fiber to the PVC/ENR blends. However the i...
2008-01-01
Effect of host nutrition on immunity and local immune response of rabbits to Obeliscoides cuniculi
International Nuclear Information System (INIS)
In a series of experiments carried out on young and adult rabbits the effect of isocaloric low protein diets containing 4% or 8% protein compared with a diet containing 21% protein on Obeliscoides cuniculi infection was studied. The pathogenesis, resistance and local immunity were assessed after single infections with 10,000 larvae or reinfection with 5000 larvae. Live weight gain was reduced in young and adult rabbits fed the low protein diets, but the establishment of parasites was not substantially influenced by protein deprivation. However, development of worms in the histotrophic phase and parasite fecundity were impaired in association with the low protein diet. Moreover, mild anaemia as well as changes in the mucosal immune response as a result of infection were related to the level of dietary protein. (author). 30 refs, 6 figs, 5 tabs.
1987-05-11
Bilateral primary breast neuroendocrine carcinoma in a young woman: Report of a case
British Library Electronic Table of Contents (United Kingdom)
Bilateral breast carcinoma accounts for approximately 5% of all patients with breast cancer, while neuroendocrine breast carcinomas comprise less than 5% of invasive breast carcinomas. In addition, most patients with breast neuroendocrine carcinomas are older. Therefore, bilateral primary breast neuroendocrine carcinoma at a young age is extremely rare. We herein report bilateral neuroendocrine carcinoma of the breast in a 29-year-old woman who underwent bilateral lumpectomy with the initial symptom of bilateral nipple discharge. Grossly, the lesions in both breasts were masses with infinite margins. Histologically, this case was consistent with primary neuroendocrine carcinoma arising in bilateral breasts. Cells from both breast tumors were positive for chromogranin A, neuron-specific eno...
2011-01-01
British Library Electronic Table of Contents (United Kingdom)
Abstract Micronutrient deficiencies are a public health concern among young children in low-income countries, and novel strategies are needed to improve the nutritional status of children at risk. One promising approach is the use of lipid-based nutrient supplements (LNS), which can be added to complementary food at the time of consumption. The optimal amount of zinc to include in LNS is uncertain, and concerns have been expressed about possible adverse effects of zinc on sensory characteristics of LNS. We conducted a series of acceptability studies of LNS containing either 0 or 10-mg of zinc per daily 20-g LNS dose among Burkinabe children 9-15 months old and their mothers. These acceptability studies included observations of children's consumption, maternal and child sensory reaction to ...
2011-01-01
British Library Electronic Table of Contents (United Kingdom)
The survival of acetabular components depends on several factors: wear, osteolysis and septic or aseptic loosening. Osteolysis seems to be the main cause for concern in cementless arthroplasties. Acetabular osteolysis results from particle debris and segmental unloading of acetabular bone by rigid sockets. We investigated a cementless elastic monoblock socket with regard to acetabular osteolysis and aseptic loosening in a cohort of young patients. We evaluated 158 hip arthroplasties with a minimum follow-up of ten?years (ten to 18) and a mean age of 42?years (18?50). The overall revision rate at 14?years was 80% with a 98% survival rate for aseptic loosening. The mean polyethylene wear rate was 0.11?mm/year. Progressive acetabular osteolysis was seen in 3% of patients evaluated. In conclus...
2011-01-01
Upper Limits from HESS Observations of AGN in 2005-2007
Very high energy (VHE; >100 GeV) observations of a sample of selected active galactic nuclei (AGN) were performed between January 2005 and April 2007 with the High Energy Stereoscopic System (HESS), an array of imaging atmospheric-Cherenkov telescopes. Significant detections are reported elsewhere for many of these objects. Here, integral flux upper limits for twelve candidate very high energy (VHE; >100 GeV) gamma-ray emitters are presented. In addition, results from HESS observations of four known VHE-bright AGN are given although no significant signal is measured. For three of these AGN (1ES 1101-232, 1ES 1218+304, and Mkn 501) simultaneous data were taken with the Suzaku X-ray satellite.
2007-01-01
The number and metallicities of the most metal-poor stars
Simple, one-zone models for inhomogeneous chemical evolution of the Galactic halo are used to predict the number fraction of zero-metallicity, Population III stars, which currently is empirically estimated at < 4e-4. These analytic models minimize the number of free parameters, highlighting the most fundamental constraints on halo evolution. There are disagreements of at least an order of magnitude between observations and predictions in limiting cases for both homogeneous Simple Model and Simple Inhomogeneous Model (SIM). Hence, this demonstrates a quantitative, unambiguous discrepancy in the observed and expected fraction of Population III stars. We explore how the metallicity distribution of the parent enrichment events f(z_0) drives the SIM and predictions for the Population III fraction. The SIM shows that the previously-identified "high halo" and "low halo" populations are consistent with a continuous evolutionary progression, and therefore may not ...
2003-01-01
The Concentration-Density Relation of Galaxies in Las Campanas Redshift Survey
We report the results of the evaluation of the ``concentration-density'' relation of galaxies in the local universe, taking advantage of the very large and homogeneous data set available from the Las Campanas Redshift Survey (Shectman et al. 1996). This data set consists of galaxies inhabiting the entire range of galactic environments, from the sparsest field to the densest clusters, thus allowing us to study environmental variations without combining multiple data sets with inhomogeneous characteristics. Concentration is quantified by the automatically-measured concentration index $C$, which is a good measure of a galaxy's bulge-to-disk ratio. The environment of the sample galaxies is characterized both by the three-space local galaxy density and by membership in groups and clusters. We find that the distribution of C in galaxy populations varies both with local density and with cluster/group membership: the fraction of centrally-concentrated galaxies increases ...
1999-01-01
Status of combined point source search with neutrino telescopes IceCube and AMANDA
Energy Technology Data Exchange (ETDEWEB)
In this talk, we summarize recent results obtained from the combined neutrino telescopes IceCube and AMANDA. The combined approach, including data taken from both detectors simultaneously, is compared to other analyses that are using IceCube only data. The main benefit of the combined detector is its improved performance at low energies, meaning energies below 1 TeV (close to the energy threshold of the detector). The discussion is focused on the search for extra-terrestrial neutrinos from candidate sources in our Galaxy. Using appropriate cuts, the sensitivity can be optimized for soft spectra neutrino sources. With the resulting data sample, several studies are performed: an unbinned Galactic Plane Scan and a Cygnus region analysis: the Multi Point Source analysis. The current status of these analyses is presented.
2010-07-01
Measurement of the antiproton/proton ratio in the few-TeV energy range with ARGO-YBJ
Cosmic ray antiprotons provide an important probe for the study of cosmic ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. The ARGO-YBJ experiment is observing the Moon shadow with high statistical significance at an energy threshold of a few hundred GeV. Using all the data collected until November 2009, we set two upper limits on the antip/p flux ratio: 5% at an energy of 1.4 TeV and 6% at 5 TeV with a confidence level of 90%. In the few-TeV range the ARGO-YBJ results are the lowest available, useful to constrain models for antiproton production in antimatter domains.
2010-01-01
Indirect Dark Matter Signals from EGRET and PAMELA compared
Dark Matter annihilation (DMA) may yield an excess of gamma rays and antimatter particles, like antiprotons and positrons, above the background from cosmic ray interactions. The excess of diffuse Galactic Gamma Rays from EGRET shows all the features expected from DMA. The new precise measurements of the antiproton and positron fractions from PAMELA are compared with the EGRET excess. It is shown that the charged particles are strongly dependent on the propagation model used. The usual propagation models with isotropic propagation models are incompatible with the recently observed convection in our Galaxy. Convection leads to an order of magnitude uncertainty in the yield of charged particles from DMA, since even a rather small convection will let drift the charged particles in the halo to outer space. It is shown that such anisotropic propagation models including convection prefer a contribution from DMA for the antiprotons, but the rise in the positron fraction, ...
2009-01-01
Galaxy rotation curves: the effect of Formula Not Shown force
British Library Electronic Table of Contents (United Kingdom)
Using the Galaxy as an example, we study the effect of Formula Not Shown force on the rotational curves of gas and plasma in galaxies. Acceptable model for the galactic magnetic field and plausible physical parameters are used to fit the flat rotational curve for gas and plasma based on the observed baryonic (visible) matter distribution and Formula Not Shown force term in the static MHD equation of motion. We also study the effects of varied strength of the magnetic field, its pitch angle and length scale on the rotational curves. We show that Formula Not Shown force does not play an important role on the plasma dynamics in the intermediate range of distances 6?12?kpc from the centre, whilst the effect is sizable for larger r (r?15?kpc), where it is the most crucial.
2011-01-01
Experimental measurement of low-energy antiprotons in the cosmic radiation
Energy Technology Data Exchange (ETDEWEB)
Researchers report results from the Low Energy Antiproton Experiment (LEAP), a balloon-borne instrument which was flown in August, 1987. They found a value of 4.2 by 10-6 for the antiproton to proton ratio in the energy range from 120 MeV to 600 MeV at the top of the atmosphere. In particular, this experiment places an upper limit on the flux almost an order of magnitude below the reported flux of Buffington et al. This upper limit allows us to place significant constraints on both the primordial black hole and weakly interacting Majorana Fermion hypothesis, as well as on the low energy processes in more conventional models of galactic cosmic ray antiproton production.
1990-01-01
Cosmological Questions for the European Southern Observatory Very Large Telescope
The next decade promises an observational revolution which will change cosmology forever. The precise measurement of the angular anisotropy of the cosmic microwave background should specify to a few percent all of the parameters of the cosmological model which effect astrophysics. The growth of structure will then be determined (but not yet observed) until gravitational collapse becomes highly non-linear and stars, galaxies and active galactic nuclei (AGN) form. These processes are hard to model with basic physics because they are complex and allow a rich variety of expression. Instead observations will determine when the first stars and quasars formed, and how and when galaxies assembled. If we can reconcile the numerous contradictions which characterize the subject today, cosmology will become a mature subject, founded on the agreement between detailed, inclusive and realistic models, which make precise predictions, and the wealth of new data which will come from ...
1996-01-01
A simple model for AGN feedback in nearby early-type galaxies
British Library Electronic Table of Contents (United Kingdom)
Abstract Recent work (Schawinski et al.) indicates that star-forming early-type galaxies residing in the blue cloud migrate rapidly to the red sequence within around a Gyr, passing through several phases of increasingly strong active galactic nucleus (AGN) activity in the process. We show that natural depletion of the cold gas reservoir through star formation (i.e. in the absence of any feedback from the AGN) induces a blue-to-red reddening rate that is several factors lower than that observed by Schawinski et al. This is because the gas depletion rate due to star formation alone is too slow, implying that another process needs to be invoked to remove cold gas from the system and accelerate the reddening rate. We develop a simple phenomenological model, in which a fraction of the AGN-s lum...
2011-01-01
This report describes a technique of inserting an implantable venous access port (portacath) through a thrombosed and occluded vein employing a pre-existing peripherally inserted central catheter (PICC) as the route of access. The PICC was used as a conduit for venous access in a way that has not been described previously in the literature. This procedure was performed in a young patient with cystic fibrosis in an effort to prevent the use of his virgin contralateral veins, which might be used in the future.
2010-02-15
This study examined preliminary psychometric properties of the Teaching Practices Observation Scale (TPOS), a newly developed observational taxonomy for assessing teacher behaviors during free play with young children. Behaviors of 42 child caregivers and junior kindergarten teachers were coded using a combination of time-sampling, event-sampling, and behavior ratings. Findings support the validity of observational coding scheme. (Author/KB)
1998-12-01
...Site Home About The Project Advisory Board Advisory Board Kenneth Geiser Omar Friella Darryl Young Jennie Curtis Michael Maniates Stuart Baker Beverly Thorpe Erica Priggen Kenneth Geiser is Professor of Work Environment and Director of the Lowell Center for Sustainable Production at the University of Massachusetts Lowell. Ken is one of the authors of the landmark Massachusetts Toxics Use Reduction Act and served as Director of the Massachusetts Toxics Use Reduction ...
UK PubMed Central (United Kingdom)
Lower respiratory tract infections are one of the leading causes of morbidity and mortality in children worldwide. Recent technological advances in the field of molecular biology have allowed virologists...Full Text Available
2010-12-01
UK PubMed Central (United Kingdom)
BackgroundThe Plasmodium falciparum pre-erythrocytic stage candidate vaccine RTS,S is being developed for protection of young children against...Full Text Available
DEFF Research Database (Denmark)
A previously healthy young man experienced several episodes of syncope while being treated with tenofovir, emtricitabine and nevirapine initiated during primary HIV-1 infection. Symptoms disappeared after discontinuation of antiretroviral therapy and we suggest that syncope may be a side effect to one of the three antiretroviral drugs that has not been described previously.
2008-01-01
Sustainable managment of the weaner pig through nutrition
Environmental Research Database
DescriptionIn young pigs the post-weaning period is generally characterised by a marked reduction in voluntary feed intake, poor growth and development, and diarrhoea. The associated reduction in digestive and absorptive capacity of the gastrointestinal tract decreases the overall efficiency of nutrient capture and utilisation, thereby causing an increase in nutrient loading to the environment. The reduction in digestive and absorptive efficiency after weaning has implications for lifetime performance be [continued...
2006-01-31
... Future Job Fund Scheme Goodwood Allotments Location: Goodwood Allotments Work undertaken by long-term unemployed young people under the Future Jobs Fund (FJF) transforms derelict allotments into a readily workable space for the local community. Western Park Location: Western Park, Hinckley Road, Leicester Groundwork conservation officers and Future Jobs Fund staff renew a Western Park spinney making it a better place for all. Bhavyesh ...
Shorter anogenital distance predicts poorer semen quality in young men in Rochester, New York
DEFF Research Database (Denmark)
In male rodents, anogenital distance (AGD) provides a sensitive and continuous correlate of androgen exposure in the intrauterine environment and predicts later reproductive success. Some endocrine-disrupting chemicals can alter male reproductive tract development, including shortening AGD, in both rodents and humans. Whether AGD is related to semen quality in human is unknown.
2011-01-01
UK PubMed Central (United Kingdom)
Pneumococcal disease in young children has not been as well characterized in East Africa as it has been in industrialized countries. Although pneumococci are likely to cause substantial mortality...Full Text Available
2009-03-01
UK PubMed Central (United Kingdom)
Anaplastic lymphoma kinase-positive, anaplastic large cell lymphoma (ALK+ ALCL) is an aggressive non-Hodgkin lymphoma of T/null immunophenotype that is most prevalent in children and young adults. The...Full Text Available
2011-02-15
... I worked on the Young City Farmers course in 2008, where I was voted the best-spoken bus driver and teacher the participants had ever had!! I am a representative of the University for widening participation and outreach, for my enthusiasm, communication and personal skills. I look forward to meeting you, welcoming you to the College and helping with your learning and progression. Sam Parkes Hi I'm ...
... Based in the Philippines, it has a broad remit, covering all philosophical topics, but with a particular focus on analytic ...net/ Cultura is a Romanian-based international journal devoted to philosophy of culture and axiology (the study of value). It aims ...edu/ Aporia is an online undergraduate philosophy journal based at Brigham Young University in Utah, USA. All articles are written by undergraduates,...edu/pcs/basic.html Theoretical and Conceptual Advances in the Cognitive Neuroscience of Self Representation: Representations of the Minimal Self in Self-Narrative is ...
... This is true because a shorter residence time means that ground water moves 'faster.' Thus, contamination will get to the drinking well from the recharge area (point of entry) faster if the ground water is younger. However, it has been difficult to measure the exact age of young ground water. The conventional indicator has been tritium, a radioactive form of hydrogen, but its ...
Microradiographic investigations of bone mineralisation in premature and young infants
International Nuclear Information System (INIS)
The paper intends to lay down the fundamentals of normal mineralisation in the perinatal phase as a basis for investigations of disturbed mineralisation. Data are presented on the percentage area of the mineralized osseous tissue, the osteocyte density, and the mineral contents of healthy bones at this age. Comparative morphological examinations of thin bone sections and microradiographs give a picture of bone development at this age. (orig./AJ).
Magnetization and magnetostriction curves for highly magnetostrictive materials
Energy Technology Data Exchange (ETDEWEB)
The macroscopic behavior of magnetostrictive materials results from domain evolutions occurring at a microscopic scale. The author shows how to compute magnetization and magnetostriction curves by appraising the behavior of the underlying microstructures. The method hinges on an averaging device (Young measures), which allows one to pass from the microscopic to the macroscopic scale. He takes into account the kinematical constraints on the accommodation of elastic effects, and he highlights the role of material symmetry in the selection of energetically optimal microstructures.
1994-12-31
Klippel-feil syndrome with situs inversus. A rare association
International Nuclear Information System (INIS)
Klippel-Feil Syndrome (KFS) is a congenital anomaly characterized by a defect in the formation or segmentation of the cervical vertebrae. The clinical triad consists of short neck, low posterior hairline and limited neck movement. Multiple congenital anomalies have been associated with this disease. This is a case of KFS in a young girl along with situs inversus, which is an extremely rare association. Various systemic associations occurring in this multi-system disorder are also discussed. (author)
2008-04-01
UK PubMed Central (United Kingdom)
Newly hatched chicks were dosed orally with a Salmonella typhimurium wild-type strain, an S. enteritidis wild-type strain, and a genetically defined S. enteritidis aroA vaccine candidate, strain CVL30....Full Text Available
1994-11-01
IDEAS: Oxford Review of Economic Policy, Oxford University Press
...Older Siblings by Adriaan R Soetevent & Peter Kooreman 392-415 Vocational Training and Gender: Wages and Occupational Mobility among Young Workers by Bernd Fitzenberger & Astrid Kunze 416-438 Gender Role Attitudes and the Labour-market Outcomes of Women across OECD Countries by Nicole M Fortin 439-461 Gender, Time Use, and Public Policy over ...
Fundamentals of polymeric materials
Energy Technology Data Exchange (ETDEWEB)
The polymer industry is a young industry that has undergone tremendous growth and change over the last sixty years. Many important discoveries in polymer science have been accidental. Most of the learning has been by trial and error and most of the understanding is still basically empirical--make a polymer material or compound and then put it to the test to study what it is and how it performs. This article provides an overview of what polymers and polymer compounds are, why they behave as they do, and it discusses several examples of failures of rubber and plastic components.
1998-12-31
Disk's Spiral Arms Point to Possible Planets
National Aeronautics and Space Administration (NASA)
Simulations of young stellar systems suggest that planets embedded in a circumstellar disk can produce many distinctive structures, including rings, gaps and spiral arms. This video compares computer simulations of hypothetical systems to an image of system SAO 206462 taken by the Subaru Telescope and its HiCIAO instrument. n nCredit: NASA Goddard Space Flight Center/NCSA
2011-10-18
UK PubMed Central (United Kingdom)
Bovine paratuberculosis is caused by infection of young calves with Mycobacterium avium subsp. paratuberculosis. In some of the chronically infected cows the long asymptomatic...Full Text Available
2001-03-01
UK PubMed Central (United Kingdom)
Experiments were conducted with field-grown cotton (Gossypium hirsutum L.) in 1985 and 1986 to determine effects of water deficit on levels of conjugated indole 3-acetic...Full Text Available
1988-01-01
Calculation method of elastic moduli of textured two-phase titanium alloys
International Nuclear Information System (INIS)
On the basis of symmetry way of texture description a calculation method of elastic moduli of two-phase titanium alloys with rolling texture has been suggested. Efficiency of the calculation formulas is checked by comparing the calculation results of Young modulus anisotropy in the sheet plane of (#alpha#+#beta#)-titanium alloy VT23 with the experimental data.
Energy Technology Data Exchange (ETDEWEB)
This is an account of the initial struggles and subsequently successful career of a young woman growing up in prewar Australia with the overriding desire to become a physicist despite various problems and prejudices. The book provides first-hand accounts of wartime radar research and development in Australia; the immediately post-war era in nuclear physics at the Cavendish Laboratory, Cambridge; and work in the Nuclear Physics Division at AERE Harwell in the period from the 1950s onwards. (UK).
1991-01-01
UK PubMed Central (United Kingdom)
Using QCT, we made a longitudinal, population-based assessment of rates of bone loss over life at the distal radius, distal tibia, and lumbar spine. Cortical bone loss began in perimenopause in women...Full Text Available
2008-02-01
2004 Reversible Associations in Structure & Molecular Biology
Energy Technology Data Exchange (ETDEWEB)
The Gordon Research Conference (GRC) on 2004 Gordon Research Conference on Reversible Associations in Structure & Molecular Biology was held at Four Points Sheraton, CA, 1/25-30/2004. The Conference was well attended with 82 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students.
2005-03-23
Radiation hardening technologies facing total dose, S.E.U. and S.E.L. in spatial environment
International Nuclear Information System (INIS)
Space particles act on semiconductor devices by creating charges (electrons, holes) in the silicon and the silicon dioxide, and by creating displacement damage. These primary phenomena alter the electrical parameters of MOS and bipolar devices (threshold voltage V_t, mobility #mu#, conductivity #sigma#, current gain #beta#). The dose rate is not important in space (a few rad (Si)/h) but as the durations of space expeditions are on average from seven to twelve years, the total dose is an aggravating factor in the behaviour of the electrical parameters and also in device operation. The total dose effect from the beginning of charge creation (ionization) to the parameter shifts is reviewed. One can note that this effect is permanent because there will almost always be charge creation in space. Another important phenomenon is called the Single Event Upset (S.E.U.) and caused by the heavy ions and the protons which come from the galactic rays. The consequence of S.E.U. ...
Energy Technology Data Exchange (ETDEWEB)
We analyze the timing of photons observed by the MAGIC telescope during a flare of the active galactic nucleus Mkn 501 for a possible correlation with energy, as suggested by some models of quantum gravity (QG), which predict a vacuum refractive index {approx_equal}1+(E/M{sub QGn}){sup n}, n=1,2. Parametrizing the delay between {gamma}-rays of different energies as {delta}t={+-}{tau}{sub l}E or {delta}t={+-}{tau}{sub q}E{sup 2}, we find {tau}{sub l}=(0.030{+-}0.012) s/GeV at the 2.5-{sigma} level, and {tau}{sub q}=(3.71{+-}2.57)x10{sup -6} s/GeV{sup 2}, respectively. We use these results to establish lower limits M{sub QG1}>0.21x10{sup 18} GeV and M{sub QG2}>0.26x10{sup 11} GeV at the 95% C.L. Monte Carlo studies confirm the MAGIC sensitivity to propagation effects at these levels. Thermal plasma effects in the source are negligible, but we cannot exclude the importance of some other source effect.
2008-10-16
Study of the thermodynamic properties of (U,Ce)O{sub 2}
Energy Technology Data Exchange (ETDEWEB)
The X-ray diffraction analysis of (U,Ce)O{sub 2} with the CeO{sub 2} contents ranging from 0 to 20 mol% CeO{sub 2} was performed at room temperature to obtain the variation in the lattice parameter with the CeO{sub 2} content. Ultrasonic pulse echo measurements were also carried out to estimate the change in the mechanical properties of (U,Ce)O{sub 2} with the CeO{sub 2} content. The lattice parameter of (U,Ce)O{sub 2} was found to decrease with increasing CeO{sub 2} content. The variation in the lattice parameter with the CeO{sub 2} content closely followed the Vegard law. The shear and longitudinal velocities in (U,Ce)O{sub 2} were found to decrease with increasing CeO{sub 2} content. The Young`s and shear moduli, and Poisson`s ratio estimated from the wave velocities decreased with the CeO{sub 2} content. No mechanical property showed anomaly in low CeO{sub 2} content region. (orig.).
1997-08-01
Rotation periods of late-type stars in the young open cluster IC 2602
We present the results of a monitoring campaign aimed at deriving rotation periods for a representative sample of stars in the young (30 Myr) open cluster IC 2602. Rotation periods were derived for 29 of 33 stars monitored. The periods derived range from 0.2d (one of the shortest known rotation periods of any single open cluster star) to about 10d (which is almost twice as long as the longest period previously known for a cluster of this age). We are able to confirm 8 previously known periods and derive 21 new ones, delineating the long period end of the distribution. Despite our sensitivity to longer periods, we do not detect any variables with periods longer than about 10d. The combination of these data with those for IC 2391, an almost identical cluster, leads to the following conclusions: 1) The fast rotators in a 30 Myr cluster are distributed across the entire 0.5 < B-V < 1.6 color range. 2) 6 stars in our sample are slow rotators, with periods longer ...
1999-01-01
Physical properties of Ti/sub 50/Be/sub 40/Zr/sub 10/ glass
Continuous metallic glass ribbons were produced by mejans of liquid-quenching at rates >10/sup 50/C/s. The ribbons, typically 30 ..mu..m thick and 1 to 2 mm wide, were determined to be glassy by X-ray diffraction (XRD) employing CuK..cap alpha.. and MoK..cap alpha.. radiation. Mechanical properties of the as-quenched product were determined by measurements of hardness, tensile strength and Young's modulus. The Vicker's diamond pyramid microhardness (H/sub V/) was measured on epoxy mounted samples using a Lietz Miniload instrument with a 100 g load. Tensile tests were conducted in an Instron machine using specimens which were hand-polished to produce smooth, parallel sides. Young's modulus (E) is given by the relationship rho V/sub E/sup 2//. V/sub E/, the velocity of extensional mode waves, was measured by the pulse-echo technique using a Panametrics Intervalometer and glass density, rho, was obtained by the liquid ...
1977-09-01
Oil palm empty fruit bunch (OPEFB) fiber reinforced PVC/ENR blend-electron beam irradiation
Energy Technology Data Exchange (ETDEWEB)
The effect of irradiation on the tensile properties of oil palm empty fruit bunch (OPEFB) fiber reinforced poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blend using HAAKE Rheomixer at 150 deg. C. The composites were then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 0 to 100 kGy in air and room temperature. The tensile strength, Young's modulus, elongation at break and gel fraction of the composites were measured. Comparative studies were also made by using poly(methyl acrylate) grafted OPEFB fiber in the similar blend system. An increase in tensile strength, Young's modulus and gel fraction, with a concurrent reduction in the elongation at break (Eb) of the PVC/ENR/OPEFB composites were observed upon electron beam irradiation. Studies revealed that grafting of the OPEFB fiber with methyl acrylate did ...
2007-12-15
Multi-wavelength observations of the young binary system Haro 6-10: The case of misaligned discs
Context. We present a multi-wavelength, high-resolution observational survey of the young binary system Haro 6-10 (GV Tau, IRAS 04263+2426), which is harbouring one of the few known infrared companions. Aims. The primary goal of this project is to determine the physical and geometrical properties of the circumstellar and circumbinary material in the Haro 6-10 system. Methods. High-resolution optical (HST/WFPC2) and near-infrared (VLT/NACO) images in different bands were analysed to investigate the large-scale structures of the material around the binary.Mid-infrared interferometry (VLTI/MIDI) and spectroscopy (TIMMI2 at the 3.6m ESO telescope) were carried out to determine the structure and optical depth of the circumstellar material around the individual components. Results. The multi-wavelength observations suggest that both components of the binary system Haro 6-10 are embedded in a common envelope. The measured extinction indicates a dust composition of the ...
2011-01-01
Keck Diffraction-Limited Imaging of the Young Quadruple Star System HD 98800
This paper presents diffraction-limited 1-18 micron images of the young quadruple star system HD 98800 obtained with the W. M. Keck 10-m telescopes using speckle and adaptive optics imaging at near-IR wavelengths and direct imaging at mid-IR wavelengths. The two components of the visual binary, A and B, both themselves spectroscopic binaries, were separable at all wavelengths, allowing us to determine their stellar and circumstellar properties. Combining these observations with spectroscopic data from the literature, we derive an age of 10 Myr, masses of 0.93 and 0.64 M_sun and an inclination angle of 58 deg for the spectroscopic components of HD 98800 B, and an age of 10 Myr and a mass of 1.1 M_sun for HD 98800 Aa. Our data confirm that the large mid-IR excess is entirely associated with HD 98800 B. This excess exhibits a black body temperature of 150 K and a strong 10 micron silicate emission feature. The theoretical equilibrium radius of large, perfectly ...
2001-01-01
Evaluation of magnetization transfer ratios for breast tissues and breast diseases
Energy Technology Data Exchange (ETDEWEB)
To determine MTRs for normal structures and benign diseases in the breast two-dimensional magnetization transfer imaging was performed in 62 patients and in 3 young female volunteers. With regard to the MTRs of measurements in the normal breast tissues, fat tissues which is close to simple cysts in MTRs show little transfer of longitudinal magnetization. MTRs of the muscles was 15.15{+-}6.22%, which exceeded those of breast parenchyma. The breast parenchyma didn`t show the change of MTR value due to the difference of patient age and due to variable amount of fat and fibrous tissues. Breast parenchyma in the two young volunteers clearly showed biphasic change of MTR values in accordance with the menstrual cycle; little transfer value was due to hydration in the postovulatory period and high transfer value was due to dehydration in the preovulatory period. In the remaining one volunteer during lactation period, mammary parenchyma shows sever ...
1997-03-01
Vegetation re-establishment on a hardwood forest site denuded by brine
Energy Technology Data Exchange (ETDEWEB)
Brine from active oil wells seeped through the soil of a forested site in north-western Pennsylvania and killed all vegetation in its path, leaving the affected area unproductive and unsightly. After the brine source was eliminated, herbaceous plants, shrubs and forest tree seedlings became established and developed rapidly. Establishment began in the first year and by Year 4 the site had developed into a healthy young forest. Results show that Allegheny hardwood forest sites damaged by brine water will rapidly revegetate once the brine water discharge is stopped if there is a seed supply and if the area is fenced to exclude deer. 3 figs., 12 refs.
1989-04-01
Uptake and translocation of {sup 137}Cs by Houttuynia cordata (in water culture)
Energy Technology Data Exchange (ETDEWEB)
The water culture experiment of Houttuynia cordata of the medicinal plant was carried out, and basic study on {sup 137}Cs accumulation characteristic and internal circulation in H. cordata in the fruiting stage was investigated since the flowering season. H. cordata accumulated 80% of {sup 137}Cs absorbed unlike K to the root, rhizome, terminal bud of the underground part for the rhizome reproduction. {sup 137}Cs content to the young leaf, spike, involucre increased in the flowering season. Thereafter, {sup 137}Cs was recirculated to the developing organs in second generations such as the rhizome and bud. (author)
2001-08-01
Propagation of jarrah (Eucalyptus marginata) by organ and tissue culture
Energy Technology Data Exchange (ETDEWEB)
Methods are described for the production of callus and subsequent shoot and root induction and multiplication using stamen filaments, nodes of young stems of mature trees or cotyledon petioles. A high frequency of contamination occurred using nodal sections from mature trees, whereas up to 100% sterility was obtained with cotyledons and stamens. The rooting % of shoot cultures from nodes or stamen callus was low compared with that of shoots from seedling callus. Considerable variation was observed between clones from different trees in their ability to produce shoots and roots. 27 references
1982-01-01
Energy Technology Data Exchange (ETDEWEB)
Posttraumatic tibia valga is a well-recognized complication following fracture of the upper tibial metaphysis in young children. We present a case of a child who developed a valgus deformity following fracture of the proximal tibia and fibula in which quantitative bone scintigraphy at 5 months after injury demonstrated increased uptake at the proximal tibial growth plate with proportionally greater uptake on the medial side. This finding suggests that the valgus deformity in this patient was due to a relative increase in vascularity and consequent overgrowth of the medial portion of the proximal tibial physis.
1987-07-01
International Nuclear Information System (INIS)
Posttraumatic tibia valga is a well-recognized complication following fracture of the upper tibial metaphysis in young children. We present a case of a child who developed a valgus deformity following fracture of the proximal tibia and fibula in which quantitative bone scintigraphy at 5 months after injury demonstrated increased uptake at the proximal tibial growth plate with proportionally greater uptake on the medial side. This finding suggests that the valgus deformity in this patient was due to a relative increase in vascularity and consequent overgrowth of the medial portion of the proximal tibial physis.
Scientific Electronic Library Online (English)
Abstract in english Odontopus brevirostris (Hustache, 1936) feeding on Annona squamosa L., A. cherimola Mill., A. glabra L., and A. muricata L. was observed. The last three host plants are recorded for the first time. The endophitic oviposition occurs in the veins of the ventral surface of the young leaves. The larvae, leaf miners, eat the parenchyma and the adults make small holes in the leaves. The pupation occurs in spherical cocoons protected by a sort of nest (pupation chamber) between the two epidermal layers.
2002-01-01
Nuclear education in Russia: Status, peculiarities, problems and perspectives
Energy Technology Data Exchange (ETDEWEB)
The paper is devoted to analysis of Russian nuclear education system: its current status, specific features, difficulties and prospects. Russian higher education system in nuclear engineering has been created simultaneously with the development of nuclear industry, and the system completely satisfied all industrial demands for the specialists of different qualification levels. For the past several decades, nuclear education has lost its attractiveness to young people. The paper discusses the actions to be undertaken for reversing the situation. The paper underlines particularly the special role of international collaboration and all-European integration of nuclear educational programmes for further development of nuclear education all over the world. (author)
2005-07-01
International Nuclear Information System (INIS)
Measurements of the humeral cortical thickness demonstrate that generalised osteoporosis in female Bantu commences in the fifth decade and gradually increases until, in the ninth decade, all subjects are osteoporotic. The combined cortical thickness (CCT) of the humerus in young adults is very similar to that found previously in a white London population and the loss of cortex with age is very similar. It is concluded that the known low incidence of femoral neck fracture in Bantu is not due to a lower incidence of generalised osteoporosis but to environmental factors. The chief environmental factor postulated is the greater amount of physical work performed by the Bantu. A more careful mode of walking is suggested as a subsidiary cause. (orig.).
Effect of protein malnutrition on the metabolism of bone collagen in albino rats
International Nuclear Information System (INIS)
The effect of protein malnutrition on the metabolism of collagen in bone was studied in young female albino rats after a single injection of "3H-proline. Both specific and total radioactivities of hydroxyproline in the total collagen of the bone were found to decrease in the protein-deficient animals, indicating decreased rate of collagen synthesis. In the urine the amount of hydroxyproline excreted and total radioactivity of "3H-hydroxyproline were greatly decreased. The results of the present investigation therefore clearly indicate decreased synthesis and catabolism of collagen in bones of protein deficient animals compared to controls. (auth.).
1981-01-01
Energy Technology Data Exchange (ETDEWEB)
We report here the imaging findings of a rare case of a lethal form of Gorham disease in a young female patient. Multimodality imaging findings over 13 year-follow-up demonstrated progressive wide spread skeletal and soft tissue abnormalities with permeative osteolysis, pathological fractures and severe skeletal deformities. Unusual extensive osseous and soft tissue pneumatosis was illustrated on cross-sectional studies. The progressive nature of this form of Gorham disease and the subsequent complications eventually culminated in patient's death. (orig.)
2008-11-15
International Nuclear Information System (INIS)
We report here the imaging findings of a rare case of a lethal form of Gorham disease in a young female patient. Multimodality imaging findings over 13 year-follow-up demonstrated progressive wide spread skeletal and soft tissue abnormalities with permeative osteolysis, pathological fractures and severe skeletal deformities. Unusual extensive osseous and soft tissue pneumatosis was illustrated on cross-sectional studies. The progressive nature of this form of Gorham disease and the subsequent complications eventually culminated in patient's death. (orig.)
2008-11-01
Respiratory responses of young asthmatic volunteers in controlled exposures to sulfuric acid aerosol
Energy Technology Data Exchange (ETDEWEB)
Thirty-two asthmatic volunteers 8 to 16 yr of age, recruited through local schools and private physicians, were exposed in a chamber to clean air (control condition) and to sulfuric acid aerosol at a low concentration (46 +/- 11 micrograms/m3; mean +/- SD) and at a high concentration (127 +/- 21 micrograms/m3). Acid aerosols had mass median aerodynamic diameters near 0.5 microns with geometric standard deviations near 1.9. Temperature was 21 degrees C, and relative humidity was near 50%. Subjects were exposed with unencumbered oronasal breathing for 30 min at rest plus 10 min at moderate exercise (ventilation rate approximately 20 L/min/m2 of body surface). A subgroup (21 subjects) were exposed similarly to clean air and to high acid (134 +/- 20 micrograms/m3) with 100% oral breathing. Increased symptoms and bronchoconstriction were found after exercise under all exposure conditions. For the group, symptom and lung function responses were not statistically different during control and ...
1990-08-01
Dietary energy requirements of young adult men, determined by using the doubly labeled water method
International Nuclear Information System (INIS)
The autors examined the hypothesis that current recommendations on dietary energy requirements may underestimate the total energy needs of young adult men, by measuring total energy expenditure (TEE) and resting energy expenditure (REE) in 14 weight-maintaining healthy subjects leading unrestricted lives. TEE and body composition were measured by using 2H(2)18O, and REE was measured by using indirect calorimetry. All subjects had sedentary full-time occupations and participated in strenuous leisure activities for 34 #+-# 6 (SE) min/d. TEE and REE were 14.61 #+-# 0.76 and 7.39 #+-# 0.26 MJ/d, respectively, and 202 #+-# 2 and 122 #+-# 2 kJ.kg-1.d-1. There were significant relationships between TEE and both body fat-free mass (r = 0.732, P less than 0.005) and measured REE (r = 0.568, P less than 0.05). Measured TEE:REE values were significantly higher than the recommended energy requirement (1.98 #+-# 0.09, compared with 1.55 or 1.67, P less than 0.005). These ...
Variability and spectral modeling of the hard X-ray emission of GX 339-4 in a bright low/hard state
We study the high-energy emission of the Galactic black hole candidate GX 339-4 using INTEGRAL/SPI and simultaneous RXTE/PCA data. By the end of January 2007, when it reached its peak luminosity in hard X-rays, the source was in a bright hard state. The SPI data from this period show a good signal to noise ratio, allowing a detailed study of the spectral energy distribution up to several hundred keV. As a main result, we report on the detection of a variable hard spectral feature (>150 keV) which represents a significant excess with respect to the cutoff power law shape of the spectrum. The SPI data suggest that the intensity of this feature is positively correlated with the 25 - 50 keV luminosity of the source and the associated variability time scale is shorter than 7 hours. The simultaneous PCA data, however, show no significant change in the spectral shape, indicating that the source is not undergoing a canonical state transition. We analyzed the broad band ...
2010-01-01
Type Ia supernova science 2010-2020
In the next decade Type Ia supernovae (SNe Ia) will be used to test theories predicting changes in the Dark Energy equation of state with time. Ultimately this requires a dedicated space mission like JDEM. SNe Ia are mature cosmological probes --- their limitations are well characterized, and a path to improvement is clear. Dominant systematic errors include photometric calibration, selection effects, reddening, and population-dependent differences. Building on past lessons, well-controlled new surveys are poised to make strides in these areas: the Palomar Transient Factory, Skymapper, La Silla QUEST, Pan-STARRS, the Dark Energy Survey, LSST, and JDEM. They will obviate historical calibrations and selection biases, and allow comparisons via large subsamples. Some systematics follow from our ignorance of SN Ia progenitors, which there is hope of determining with SN Ia rate studies from 0
2009-01-01
The origin of large scale magnetic fields
Magnetic fields correlated on several kiloparsec scales are seen in spiral galaxies. Their origin could be due to the winding up of a primordial cosmological field or due to amplification of a small seed field by a turbulent galactic dynamo. Both options have difficulties: There is no known battery mechanism for producing the required primordial field. Equally the turbulent dynamo may self destruct before being able to produce the large scale field, due to excess generation of small scale power. The current status of these difficulties is discussed. The resolution could depend on the nature of the saturated field produced by the small scale dynamo. We argue that the small scale fields do not fill most of the volume of the fluid and instead concentrate into intermittent ropes, with their peak value of order equipartition fields, and radii much smaller than their lengths. In this case these fields neither drain significant energy from the turbulence nor convert eddy ...
1996-01-01
Two dimensional Fourier spectra of near-infrared images of galaxies provide a powerful diagnostic tool for the detection of spiral arm modulation in stellar disks. Spiral arm modulation may be understood in terms of interference patterns of outgoing and incoming density wave packets or modes. The brightness along a spiral arm will be increased where two wave crests meet and constructively interfere, but will be decreased where a wave crest and a wave trough destructively interfere. Spiral arm modulation has hitherto only been detected in grand design spirals (such as Messier 81). Spiral arm amplitude variations have the potential to become a powerful constraint for the study of galactic dynamics. We illustrate our method in two galaxies: NGC 4062 and NGC 5248. In both cases, we have detected trailing and leading m=2 waves with similar pitch angles. This suggests that the amplification mechanism is the WASER type II. In this mechanism, the bulge region reflects ...
2000-01-01
We present a detailed spectral analysis of point-like X-ray sources in the XMM-COSMOS field. Our sample of 135 sources only includes those that have more than 100 net counts in the 0.3-10 keV energy band and have been identified through optical spectroscopy. The majority of the sources are well described by a simple power-law model with either no absorption (76%) or a significant intrinsic, absorbing column (20%).As expected, the distribution of intrinsic absorbing column densities is markedly different between AGN with or without broad optical emission lines. We find within our sample four Type-2 QSOs candidates (L_X > 10^44 erg/s, N_H > 10^22 cm^-2), with a spectral energy distribution well reproduced by a composite Seyfert-2 spectrum, that demonstrates the strength of the wide field XMM/COSMOS survey to detect these rare and underrepresented sources.
2006-01-01
The Pamela Cosmic Ray Space Observatory: Detector, Objectives and First Results
PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of $10^{-8}$). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15 2006 in a $350\\times 600 km$ orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the satellite. In self-trigger ...
2009-01-01
The Mid-Infrared Narrow Line Baldwin Effect Revealed by Spitzer
We present our discovery of a narrow-line Baldwin effect, an anti-correlation between the equivalent width (EW) of a line and the flux of the associated continuum, in 5-20$\\mu$m mid-infared lines from a sample of 68 Active Galactic Nuclei (AGN), located at z$<$0.5, observed with the Infrared Spectrograph on the {\\it Spitzer Space Telescope}. Our analysis reveals a clear anti-correlation between the EW of the [SIV] 10.51$\\mu$m, [NeII] 12.81$\\mu$m, and [NeIII] 15.56$\\mu$m lines and their mid-IR continuum luminosities, while the Baldwin effect for [NeV] 14.32$\\mu$m is not as obvious. We suggest that this anti-correlation is driven by the central AGN and not circumnuclear star formation in the host galaxy. We also find that the slope of the narrow-line Baldwin effect in the mid-infrared does not appear to steepen with increasing ionization potential. Examining the dependence of the EW to the Eddington Ratio ($L/L_{Edd}$) we find no strong relationship for ...
2008-01-01
Stellar and Dust Properties of Local Elliptical Galaxies: Clues to the Onset of Nuclear Activity
We study the stellar and dust properties of a well-defined sample of local elliptical galaxies to investigate the relationship between host galaxy properties and nuclear activity. We select a complete sample of 45 ellipticals from the Palomar spectroscopic survey of nearby galaxies, which includes 20 low-luminosity active galactic nuclei classified as LINERs and 25 inactive galaxies. Using a stellar population synthesis method, we compare the derived stellar population properties of the LINER versus the inactive subsamples. We also study the dust and stellar surface brightness distributions of the central regions of these galaxies using high-resolution images obtained with the {\\it Hubble Space Telescope}. Relative to the inactive subsample, ellipticals hosting LINERs share similar total optical and near-infrared luminosity, central stellar velocity dispersions, and nuclear stellar populations as judged from their luminosity-weighted ages and metallicities. ...
2008-01-01
We numerically investigate whether and how gaseous ejecta from AGB stars can be converted into new stars within originally massive star clusters (MSCs) in order to understand the origin of multiple stellar populations in globular clusters (GCs). We adopt a scenario in which (i) MSCs with masses of M_s can be formed from high-mass, high-density giant molecular clouds (GMCs) in their host galactic building blocks embedded in dark matter halos at high redshifts and (ii) their evolution therefore can be significantly influenced by M_s, their initial locations, and physical properties of their hosts. Our 3D hydrodynamical simulations show that gaseous ejecta from AGB stars can be retained within MSCs and consequently converted into new stars very efficiently in the central regions of MSCs, only if M_s exceed a threshold mass (M_th) of ~10^6 M_sun. The new stars can correspond to the ``second generation (SG)'' of stars with higher Na and lower O abundances observed in ...
2010-01-01
The data obtained by the recent modern sky surveys enable detailed studies of the stellar distribution in the multi-dimensional space spanned by spatial coordinates, velocity and metallicity, from the solar neighborhood all the way out to the outer Milky Way halo. While these results represent exciting observational breakthroughs, their interpretation is not simple. For example, traditional decomposition of the thin and thick disks predicts a strong correlation in metallicity and kinematics at $\\sim$1 kpc from the Galactic plane; however, recent SDSS--based work has demonstrated an absence of this correlation for disk stars. Instead, the variation of the metallicity and rotational velocity distributions can be modeled using non--Gaussian functions that retain their shapes and only shift as the distance from the mid--plane increases. To fully contextualize these recent observational results, a detailed comparison with sophisticated numerical models is necessary. ...
2008-01-01
Energy Technology Data Exchange (ETDEWEB)
The X-ray spectra of {approx}200 AGN collected from Swift-BAT were analyzed to test the Unified Model for AGN. Specifically, the photon indices, high energy cutoffs, and reflection components of Sy1 and Sy2 were compared. Under the Unified Model, the photon indices and reflection components for Sy1 should be larger than Sy2 and the high energy cutoffs should be the same. Fitting a simple power law model to the sample spectra proved to be insufficient. The PEXRAV model fit the spectra of the Sy1 and Sy2 significantly better, indicating that a reflection component and/or high energy cutoff exists as the Unified Model expects. Using both the simple power law and PEXRAV models it was concluded that in the population studied, Sy1 had a larger photon index than Sy2, as expected by the Unified Model. For Sy1 and Sy2, the reflection components were found to be compatible, but given the large errors, this finding cannot be said to be evidence against the Unified Model. However, it was concluded ...
2010-08-25
We propose the Particle Swarm Optimization (PSO) as an alternative method for locating periodic orbits in a three--dimensional (3D) model of barred galaxies. We develop an appropriate scheme that transforms the problem of finding periodic orbits into the problem of detecting global minimizers of a function, which is defined on the Poincar\\'{e} Surface of Section (PSS) of the Hamiltonian system. By combining the PSO method with deflection techniques, we succeeded in tracing systematically several periodic orbits of the system. The method succeeded in tracing the initial conditions of periodic orbits in cases where Newton iterative techniques had difficulties. In particular, we found families of 2D and 3D periodic orbits associated with the inner 8:1 to 12:1 resonances, between the radial 4:1 and corotation resonances of our 3D Ferrers bar model. The main advantages of the proposed algorithm is its simplicity, its ability to work using function values solely, as well as its ability to ...
2005-01-01
Observation of the Far-ultraviolet Continuum Background with SPEAR/FIMS
We present the general properties of the far-ultraviolet (FUV; 1370-1720A) continuum background over most of the sky, obtained with the Spectroscopy of Plasma Evolution from Astrophysical Radiation instrument (SPEAR, also known as FIMS), flown aboard the STSAT-1 satellite mission. We find that the diffuse FUV continuum intensity is well correlated with N_{HI}, 100 $\\mu$m, and H-alpha intensities but anti-correlated with soft X-ray. The strongest correlation is with the H-alpha emission, and the correlation of the diffuse background with the direct stellar flux is weaker than the correlation with other parameters. The continuum spectra are relatively flat. However, a weak softening of the FUV spectra toward some sight lines, mostly at high Galactic latitudes, is found not only in direct-stellar but also in diffuse background spectra. The diffuse background is relatively softer that the direct stellar spectrum. We also find that the diffuse FUV background averaged ...
2010-01-01
New constraints on the primordial black hole number density from Galactic gamma-ray astronomy
Primordial black holes are unique probes of cosmology, general relativity, quantum gravity and non standard particle physics. They can be considered as the ultimate particle accelerator in their last (explosive) moments since they are supposed to reach, very briefly, the Planck temperature. Upper limits on the primordial black hole number density of mass $M_{\\star} = 5 10^{14}$ g, the Hawking mass (born in the big-bang terminating their life presently), is determined comparing their predicted cumulative $\\gamma$-ray emission, galaxy-wise, to the one observed by the EGRET satellite, once corrected for non thermal $\\gamma$-ray background emission induced by cosmic ray protons and electrons interacting with light and matter in the Milky Way. A model with free gas emissivities is used to map the Galaxy in the 100 MeV photon range, where the peak of the primordial black hole emission is expected. The best gas emissivities and additional model parameters are obtained by fitting the EGRET ...
2009-01-01
Microlens Parallax Measurements with a Warm Spitzer
Because Spitzer is an Earth-trailing orbit, losing about 0.1 AU/yr, it is excellently located to perform microlens parallax observations toward the Magellanic Clouds (LMC/SMC) and the Galactic bulge. These yield the so-called ``projected velocity'' of the lens, which can distinguish statistically among different populations. A few such measurements toward the LMC/SMC would reveal the nature of the lenses being detected in this direction (dark halo objects, or ordinary LMC/SMC stars). Cool Spitzer has already made one such measurement of a (rare) bright red-clump source, but warm (presumably less oversubscribed) Spitzer could devote the extra time required to obtain microlens parallaxes for the more common, but fainter, turnoff sources. Warm Spitzer could observe bulge microlenses for 38 days per year, which would permit up to 24 microlens parallaxes per year. This would yield interesting information on the disk mass function, particularly old brown dwarfs, which at ...
2007-01-01
Measurement of the antiproton/proton ratio at few-TeV energies with the ARGO-YBJ experiment
Cosmic ray antiprotons provide an important probe for the study of cosmic-ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. Cosmic rays are hampered by the Moon, therefore a deficit of cosmic rays in its direction is expected (the so-called "Moon shadow"). The Earth-Moon system acts as a magnetic spectrometer. In fact, due to the geomagnetic field the center of the Moon shifts westward by an amount depending on the primary cosmic ray energy. Paths of primary antiprotons are therefore deflected in an opposite sense in their way to the Earth. This effect allows, in principle, the search of antiparticles in the opposite direction of the observed Moon shadow. The ARGO-YBJ experiment, in stable data taking since November 2007 with an energy threshold of a few hundreds of GeV, is observing the Moon shadow with high statistical significance. Using about 1 year data, an upper limit of the antip/p flux ratio in the few-TeV ...
2009-01-01
Locally Optimally-emitting Clouds and the Narrow Emission Lines in Seyfert Galaxies
The narrow emission line spectra of active galactic nuclei are not accurately described by simple photoionization models of single clouds. Recent Hubble Space Telescope images of Seyfert 2 galaxies show that these objects are rich with ionization cones, knots, filaments, and strands of ionized gas. Here we extend to the narrow line region the ``locally optimally emitting cloud'' (LOC) model, in which the observed spectra are predominantly determined by powerful selection effects. We present a large grid of photoionization models covering a wide range of physical conditions and show the optimal conditions for producing many of the strongest emission lines. We show that the integrated narrow line spectrum can be predicted by an integration of an ensemble of clouds, and we present these results in the form of diagnostic line ratio diagrams making comparisons with observations. We also predict key diagnostic line ratios as a function of distance from the ionizing ...
1997-01-01
Launch of the Space experiment PAMELA
PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of 10^-8). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15, 2006 in a 350*600 km orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the satellite. In self-trigger mode the ...
2007-01-01
Is there an enhancement of muons at sea level from transient events?
In a recent study of a search for enhancements from the galactic center with muons at sea level using the TUPI muon telescope, we have found several ground level enhancements (GLEs) as very sharp peaks above the count rate background. This paper reports a consistent analysis of two GLEs observed in December 2003 and detected after an up-grade of the data acquisition system, which includes a noise filter and which allows us to verify that the GLEs are not mere background fluctuations. The main target of this study is a search for the origin of the GLEs. The results show that one of them has a strong correlation with a solar flare, while the other has an unknown origin, because there is neither a satellite report of a solar flare, nor prompt X-ray emission, and nor a excess of nuclei during the raster scan where the GLE was observed. Even so, two possibilities are analyzed: the solar flare hypothesis and the gamma ray burst (GRB) hypothesis. We show, by using the ...
2004-01-01
Gas and stellar dynamics in NGC 1068. Probing the galactic gravitational potential
We present Sauron 2D spectrography of the central 1.5 kpc of the nearby Sey2 galaxy NGC1068, encompassing the well-known NIR inner bar. We have successively disentangled the respective contributions of the ionized gas and stars, thus deriving their 2D distribution and kinematics. The [OIII] and Hbeta emission lines exhibit very different spatial distribution and kinematics, the latter following inner spiral arms with clumps associated with star formation. Strong inwards streaming motions are observed in both the Hbeta and [OIII] kinematics. The stellar kinematics also exhibit clear signatures of a non-axisymmetric tumbling potential, with a twist in both the velocity and h3 fields. We re-examined the long-slit data of Shapiro et al (2003) using pPXF: a strong decoupling of h3 is revealed, and the central decrease in h4 hinted in the Sauron data is confirmed. These data also suggest that NGC1068 is a good candidate for a so-called sigma-drop. We confirm the possible presence of two ...
2006-01-01
Anti-proton and positron Galactic cosmic ray (GCR) spectra are among the key targets for indirect detection of dark matter (DM). The boost factors, corresponding to an enhancement of the signal|linked to the clumpiness properties of the dark matter distribution|, have been taken as high as thousands in the past. The dramatic impact of these boost factors for indirect detection of antiparticles, for instance with the PAMELA satellite or the coming AMS-02 experiment, asks for their detailed calculation. We take into account the state-of-the-art results of high resolution N-body dark matter simulations to calculate the most likely energy dependent boost factors|linked to the GCR propagation properties|, for anti-protons and positrons. The results from extreme, but still possible, configurations of the clumpy dark matter component is also discussed. Starting from the mass and space distributions of sub-halos, the anti-proton and positron propagators are used to ...
2007-01-01
Formation and dynamical evolution of galaxies and of their components
From this vast subject, I will pick out and review three specific topics, namely the formation and evolution of bars, the formation of bulges, and the evolution during multiple major mergers. Bars form naturally in galactic discs. Their evolution is driven by the exchange of angular momentum within the galaxy. This is emitted mainly by near-resonant material in the inner disc (bar), and is absorbed by near-resonant material in the outer disc and in the halo. As a result of this, the bar becomes stronger and rotates slower. Bulges are not a homogeneous class of objects. Based on their formation history, one can distinguish three types. Classical bulges are mainly formed before the actual disc component, from collapses or mergers and the corresponding dissipative processes. Boxy/peanut bulges are parts of bars seen edge-on. Finally, disc-like bulges are formed by the inflow of material to the center due to bar torques. Major mergers bring strong and fast evolution ...
2005-01-01
Exploring Quantum Gravity with Very-High-Energy Gamma-Ray Instruments - Prospects and Limitations
Some models for quantum gravity (QG) violate Lorentz invariance and predict an energy dependence of the speed of light, leading to a dispersion of high-energy gamma-ray signals that travel over cosmological distances. Limits on the dispersion from short-duration substructures observed in gamma-rays emitted by gamma-ray bursts (GRBs) at cosmological distances have provided interesting bounds on Lorentz invariance violation (LIV). Recent observations of unprecedentedly fast flares in the very-high energy gamma-ray emission of the active galactic nuclei (AGNs) Mkn 501 in 2005 and PKS 2155-304 in 2006 resulted in the most constraining limits on LIV from light-travel observations, approaching the Planck mass scale, at which QG effects are assumed to become important. I review the current status of LIV searches using GRBs and AGN flare events, and discuss limitations of light-travel time analyses and prospects for future instruments in the gamma-ray domain.
2009-01-01
Evolution of spiral galaxies in modified gravity
We compare N-body simulations of isolated galaxies performed in both frameworks of modified Newtonian dynamics (MOND) and Newtonian gravity with dark matter (DM). We have developed a multigrid code able to efficiently solve the modified Poisson equation derived from the Lagrangian formalism AQUAL. We take particular care of the boundary conditions that are a crucial point in MOND. The 3-dimensional dynamics of initially identical stellar discs is studied in both models. In Newtonian gravity the live DM halo is chosen to fit the rotation curve of the MOND galaxy. For the same value of the Toomre parameter (Q_T), galactic discs in MOND develop a bar instability sooner than in the DM model. In a second phase the MOND bars weaken while the DM bars continue to grow by exchanging angular momentum with the halo. The bar pattern speed evolves quite differently in the two models: there is no dynamical friction on the MOND bars so they keep a constant pattern speed while the ...
2007-01-01
Energy Technology Data Exchange (ETDEWEB)
Yet designed to measure charged component of the cosmic rays, the foreseen Alpha Magnetic Spectrometer (AMS-02) could also release {gamma}-ray studies, in the energy range from GeV to TeV, using the tracker system, for {gamma}-rays converted in e{sup +}e{sup -} pair, and the electromagnetic calorimeter. In the first part of the thesis are described the calibrations and the performances of the engineering model of the calorimeter, obtained from the analysis of data taken during a test-beam performed at CERN in July 2002. In the second part of the thesis, the AMS-02 discovery potential for {gamma}-astrophysics is presented. While exposure maps of the {gamma}--sky are computed for one year of data taking with the {gamma}--detectors, the acceptance of the calorimeter is obtained from Monte-Carlo simulations. The AMS-02 potential is then estimated for signals from the Vela pulsar and for some supersymmetric signals from the Galactic Center. (author)
2004-12-15
Compact source origin of cosmic ray antiprotons
Energy Technology Data Exchange (ETDEWEB)
The flux of cosmic ray antiprotons with kinetic energies between /approximately/1 and 15 GeV is /approximately/5 times greater than the flux predicted on the basis of the leaky-box model. This excess is attributed to secondary antineutron production in compact sources. Because the antineutrons are not confined by the magnetic field of the compact source, they leave the interaction site, decay in interstellar space and account for the apparent excess cosmic ray antiproton flux. The escape and decay of neutrons produced in association with the antineutrons is a source of cosmic ray protons. Observations of the angular variation of the intensity and spectral shape of 100 MeV ..gamma..-rays produced by neutron-decay protons in the reaction p + p ..-->.. ..pi../sup 0/ ..-->.. 2..gamma.. could reveal compact-source cosmic ray production sites. COS-B observations of spectral hardening near point sources, and future high-resolution observations of galactic point ...
1989-02-01
Chemical Compositions of a sample of candidate post-AGB stars
We have derived elemental abundances for a sample of nine IRAS sources with colours similar to those of post-AGB stars. For IRAS 01259+6823, IRAS 05208-2035, IRAS 04535+3747 and IRAS 08187-1905 this is the first detailed abundance analysis based upon high resolution spectra. Mild indication of s-processing for IRAS 01259+6823, IRAS 05208-2035 and IRAS 08187-1905 have been found and a more comprehensive study of s-process enhanced objects IRAS 17279-1119 and IRAS 22223+4327 have been carried out. We have also made a contemporary abundance analysis of the high galactic latitude supergiants BD+39 4926 and HD 107369. The former is heavily depleted in refractories and estimated [Zn/H] of -0.7 dex most likely gives initial metallicity of the star. For HD 107369 the abundances of alpha and Fe-peak elements are similar to those of halo objects and moderate deficiency of s-process elements is seen. IRAS 07140-2321 despite being a short period binary with circumstellar shell ...
2011-01-01
Chandra Observations of Nuclear X-ray Emission from a Sample of Radio Sources
We present the X-ray properties of a sample of 17 radio sources observed with the Chandra X-ray Observatory as part of a project aimed at studying the X-ray emission from their radio jets. In this paper, we concentrate on the X-ray properties of the unresolved cores. The sample includes 16 quasars (11 core-dominated and 5 lobe-dominated) in the redshift range z=0.30--1.96, and one low-power radio-galaxy at z=0.064. No diffuse X-ray emission is present around the cores of the quasars, except for the nearby low-power galaxy that has diffuse emission on a scale and with a luminosity consistent with other FRIs. No high-amplitude, short-term variability is detected within the relatively short Chandra exposures. However, 1510-089 shows low-amplitude flux changes with a timescale of $\\sim$25 minutes. The X-ray spectra of the quasar cores are generally well described by a single power law model with Galactic absorption. However, in six quasars we find soft X-ray excess ...
2003-01-01
Binary compact object coalescence rates: The role of elliptical galaxies
We estimate binary compact object merger detection rates for LIGO, including the binaries formed in ellipticals long ago. Specifically, we convolve hundreds of model realizations of elliptical- and spiral-galaxy population syntheses with a model for elliptical- and spiral-galaxy star formation history as a function of redshift. Our results favor local merger rate densities of 4\\times 10^{-3} {Mpc}^{-3}{Myr}^{-1} for binary black holes (BH), 3\\times 10^{-2} {Mpc}^{-3}{Myr}^{-1} for binary neutron stars (NS), and 10^{-2} {Mpc}^{-3}{Myr}^{-1} for BH-NS binaries. Mergers in elliptical galaxies are a significant fraction of our total estimate for BH-BH and BH-NS detection rates; NS-NS detection rates are dominated by the contribution from spiral galaxies. Using only models that reproduce current observations of Galactic NS-NS binaries, we find slightly higher rates for NS-NS and largely similar ranges for BH-NS and BH-BH binaries. Assuming a detection signal-to-noise ...
2009-01-01
An alternative explanation of the COBE data
Energy Technology Data Exchange (ETDEWEB)
The COBE data on cosmic background radiation (CBR) isotropy and spectrum are generally considered to be explicable only in the context of the Big Bang theory and to be confirmation of that theory. However, this data can also be explained by an alternative, non-Big Bang model which hypothesizes an intergalactic radio-absorbing and scattering medium. Dense, force-free magnetic filaments generated by quasars, active galactic nuclei and Herbig-Haro objects can remain stable in the intergalactic medium for many Gy. They will be opaque to radiation with wavelengths longer than 100--400 microns, and essentially transparent to shorter wavelengths. They are thus capable of thermalizing and isotropizing the cosmic background radiation, and of accounting for the observed decrease of radio luminosity of galaxies within increasing distance from earth. A simple, inhomogeneous model of such an absorbing medium can reproduce both the isotropy and spectrum of the CBR within the ...
1994-12-31
Accretion onto Supermassive Black Holes in Quasars: Learning from Optical/UV Observations
Accretion processes in quasars and active galactic nuclei are still poorly understood, especially as far as the connection between observed spectral properties and physical parameters is concerned. Quasars show an additional degree of complexity compared to stars that is related to anisotropic emission/obscuration influencing the observed properties in most spectral ranges. This complicating factor has hampered efforts to define the equivalent of an Hertzsprung-Russel diagram for quasars. Even if it has recently become possible to estimate black hole mass and Eddington ratio for sources using optical and UV broad emission lines, the results are still plagued by large uncertainties. Nevertheless, robust trends are emerging from multivariate analysis of large spectral datasets of quasars. A firm observational basis is being laid out by accurate measurements of broad emission line properties especially when the source rest-frame is known. We consider the most widely ...
2006-01-01
AGN Outflows in Emission and Absorption: The SDSS Perspective
A variety of investigations have demonstrated commonalities between the Baldwin (1977) Effect, the blueshifting of CIV emission lines (e.g., Gaskell 1982; Richards et al. 2002), and the L_UV-L_X relationship (e.g., Avni & Tananbaum 1982; Strateva et al. 2005; Steffen et al. 2006); indeed all three of these observational effects may be manifestations of the same underlying (but still uncertain) physics. This commonality is of interest to investigations of accretion disk winds (e.g., Murray et al. 1995; Proga et al. 2000) from active galactic nuclei (AGN) as there is evidence that broad absorption line quasars (BALQSOs) are drawn from a parent sample of quasars that exhibit larger than average CIV blueshifts, weaker than average CIV emission line strengths, and bluer than average (intrinsic) colors. The properties of the absorption troughs appear to be dependent upon these parameters. Thus, it is suggested that not all quasars will host bona-fide BAL troughs, but ...
2006-01-01
The interaction of accretion disks with the magnetospheres of young stars can produce X-winds and funnel flows. With the assumption of axial symmetry and steady state flow, the problem can be formulated in terms of quantities that are conserved along streamlines, such as the Bernoulli integral (BI), plus a partial differential equation (PDE), called the Grad-Shafranov equation (GSE), that governs the distribution of streamlines in the meridional plane. The GSE plus BI yields a PDE of mixed type, elliptic before critical surfaces where the flow speed equals certain characteristic wave speeds are crossed and hyperbolic afterward. The computational difficulties are exacerbated by the locations of the critical surfaces not being known in advance. To overcome these obstacles, we consider a variational principle by which the GSE can be attacked by extremizing an action integral, with all other conserved quantities of the problem explicitly included as part of the overall ...
2007-01-01
Tunneling magnetoresistance from a symmetry filtering effect
International Nuclear Information System (INIS)
This paper provides a brief overview of the young, but rapidly growing field of spintronics. Its primary objective is to explain how as electrons tunnel through simple insulators such as MgO, wavefunctions of certain symmetries are preferentially transmitted. This symmetry filtering property can be converted into a spin-filtering property if the insulator is joined epitaxially to a ferromagnetic electrode with the same two-dimensional symmetry parallel to the interface. A second requirement of the ferromagnetic electrodes is that a wavefunction with the preferred symmetry exists in one of the two spin channels but not in the other. These requirements are satisfied for electrons traveling perpendicular to the interface for Fe-MgO-Fe tunnel barriers. This leads to a large change in the resistance when the magnetic moment of one of the electrodes is rotated relative to those of the other electrode. This large tunneling magnetoresistance effect is being used as the ...
2008-04-01
The temporal distribution of past and future autobiographical events across the lifespan.
Knowledge and awareness of past and future autobiographical events may be mediated by a common system that supports intentional, goal-directed behavior. The purpose of this study was to assess the correspondence of past and future autobiographical thought. In Experiment 1, 300 undergraduates aged 19 years generated and assigned dates to past and f utu re autobiographical events. Thetemporal distribution of past events replicated a power function for retention as has been described in past research. The intention function of future autobiographical events fit the inverse of this same power function, reflecting a temporality of past and future mental time travel centered around the present moment. In Experiment 2, these findings were extended to young, middle-aged, and older groups. These data provide empirical support for the notion that thinking outside of "now" is mediated by a common system, regardless of whether one is thinking about the past or the future. ...
2006-12-01
The objectives for deep scientific drilling in Yellowstone National Park
Energy Technology Data Exchange (ETDEWEB)
The western area of the United Stated contains three young silicic calderas, all of which contain attractive targets for scientific drilling. Of the three, the Yellowstone caldera complex is the largest, has the most intense geothermal anomalies, and is the most seismically active. On the basis of scientific objectives alone. it is easily the first choice for investigating active hydrothermal processes. This report briefly reviews what is known about the geology of Yellowstone National Park and highlights unique information that could be acquired by research drilling only in Yellowstone. However, it is not the purpose of this report to recommend specific drill sites or to put forth a specific drilling proposal. 175 refs., 9 figs., 2 tabs.
1987-01-01
The evolution of the Cepheid stars
International Nuclear Information System (INIS)
The evolution of intermediate and high mass stars is reviewed focusing on the interpretation of Pop I Cepheids. First, a summary is given of the classical results of stellar evolution theory for the main evolutionary phases (main sequence and core He-burning) all over the HR diagram, putting into evidence the various points of disagreement with current observational data. Second, models incorporating the effect of convective overshoot, are reviewed, and studies are presented on the rich, young clusters in the Large Magellanic Cloud, in which the models are compared with the observational data. Arguments are given to favor the adoption of models with convective overshoot instead of the classical ones. Third, new results are presented for pulsational models of the Cepheid stars, and the shape of the instability strip in the HR diagram, the number frequency-period distribution, and the mass discrepancy are discussed. 81 refs.
1990-05-28
This article examines relevant government policy documents on education and culture and discovers that Nigerian education authorities do not "discriminate" against art and culture in its articulation of educational policies per se, but lack of administrative machinery or political will has resulted in the deprivation of the Nigerian child in the process of creative activity in early childhood development. The article argues that lack of creative ability in our educational products is perhaps a major setback in the nation's quest for industrial and technological development. In this article a new art curriculum for elementary schools is advocated as a means of engaging the young child in order to attain functional educational skills necessary in the world of work.
2008-10-01
TeV gamma-rays from the Northern sky pulsar wind nebulae
Energy Technology Data Exchange (ETDEWEB)
We estimate the TeV {gamma}-ray fluxes expected from the population of young pulsars in terms of the self-consistent time-dependent hadronic-leptonic model for the high-energy processes inside the pulsar wind nebulae (PWNe). This radiation model is based on the hypothesis of Arons and collaborators who postulate that leptons are accelerated inside the nebulae as a result of resonant scattering on heavy nuclei, which in turn are accelerated in the pulsar wind region or the pulsar inner magnetosphere. Our aim is to find out which PWNe on the northern hemisphere are the best candidates for detection at energies above 60 GeV and 200 GeV by the next generation of low-threshold Cherenkov telescopes.
2005-12-01
British Library Electronic Table of Contents (United Kingdom)
Background Previous reports in adults have suggested that the effects experienced after cannabis use can be described in terms of positive and negative subtypes that are heritable and are associated with abuse and dependence. This study extends existing research by inclusion of adolescents and young adults in an offspring of twins design which makes it possible to take into account genetic and environmental risks for substance use disorder. Methods Data were collected from 725 twin members of the Vietnam Era Twin Registry, 839 of their 12-32 year old biological offspring and 427 mothers. Offspring who had ever used cannabis (n=464) were asked the degree to which they typically experienced 13 subjective effects shortly after using cannabis. Latent class analysis (LCA) was used to derive sub...
2009-01-01
Spin-down of protostars through gravitational torques
British Library Electronic Table of Contents (United Kingdom)
Abstract Young protostars embedded in circumstellar discs accrete from an angular momentum rich mass reservoir. Without some braking mechanism, all stars should be spinning at or near breakup velocity. In this paper, we perform simulations of the self-gravitational collapse of an isothermal cloud using the orion adaptive-mesh refinement code and investigate the role that gravitational torques might play in the spin-down of the dense central object. While magnetic effects likely dominate for low-mass stars, high-mass and Population III stars might be less well magnetized. We find that gravitational torques alone prevent the central object from spinning up to more than half of its breakup velocity, because higher rotation rates lead to bar-like deformations that enable efficient angular mome...
2011-01-01
Science and Society: Integrity and honesty in research
Results that contradict known physics, data manipulated, lack of vigilance by co-authors, failures in the system for scientific publication... Last September a US Committee of Enquiry unveiled one of the most serious frauds in the history of physics. Over a two year period, a young researcher at Bell Laboratories had published a large number of articles with exciting results for solid state physics, but which, alas, were fraudulent! Obviously a fraud of this magnitude is exceptional. However, it did serve to focus attention on the problem of integrity and honesty in research practices. This subject, crucial to the well-being and credibility of scientific research, will be the central theme of the lecture given by Nicholas Steneck, Professor of History at the University of Michigan. A leading expert on this issue, on which he has published extensively, he is a consultant to the Office of Research Integrity in the US, and has been closely involved in public ...
2003-01-01
Responding to diversity: the challenge of expanding basic education for young people in the south
British Library Electronic Table of Contents (United Kingdom)
This article explores the extent to which and how non-formal education (NFE) contributes to the development of a more diversified basic education system and thus to the achievement of EFA. It outlines the current nature of NFE, the frameworks provided by the EFA movement, and the evolution of reflection, policies and practices in NFE in relation to basic education as a whole. Based on significant developments in various countries across the South, the article also discusses some key challenges that ministries of education and their partners need to face in moving towards relevant and equitable diversity in education. The article posits that, despite the many problems faced by NFE, there is justification for building on its experiences and integrating these within a larger policy and system...
2008-01-01
Protoplanetary Disks of Binary Systems in Orion
Dusty primordial disks surrounding young low-mass stars are revealing tracers of stellar and planetary formation. The evolution and lifetime of these disks define the boundary conditions of the mechanisms of planet formation. Stellar companions, however, can significantly change this evolution through their tidal interactions. Stellar evolution and planet formation in binaries have to respond to an environment of truncated, quickly disappearing disks--very different compared to an isolated star environment. In order to investigate details of the influence of binarity on circumstellar disk evolution, we obtained adaptive optics supported near-infrared imaging and spectroscopy of the individual components of 22 low-mass binaries in the well-known Orion Nebula Cluster. Brackett gamma emission, which we detect in several systems, is used as a tracer for the presence of an active accretion disk around each binary component. We find a low fraction of accreting binary ...
2010-01-01
Prevalence and Incidence of HCV Infection among Vietnam Heroin Users with Recent Onset of Injection
British Library Electronic Table of Contents (United Kingdom)
HCV infection continues to spread at an alarming rate among IDU populations. The available evidence suggests that HCV is acquired relatively quickly following onset of injection. However, there are few prospective studies of HCV acquisition, particularly among IDU populations in resource-poor settings. A sample of young male heroin injectors with recent onset of injection (<4?years) was recruited in Hanoi, Vietnam for a prospective assessment of the early course of injection (n?=?179). Both behavioral and biological assessments (including detailed retrospective assessment of injection initiation) were conducted at baseline and repeated at 6-month intervals for a period of 16?months. Variables associated with HCV infection (p value?p value?=?0.0005). In multivariate logistic regression anal...
2010-01-01
Polysomaty analysis in diploid and tetraploid Portulaca grandiflora.
Polysomaty analysis of the succulent portulaca (Portulaca grandiflora Hook.) plant was carried out using flow cytometry. For both diploid and tetraploid plants, mature leaf tissue was found to have a higher level of polysomaty than young leaf tissue. Mesophyll (MP), bundle sheath (BSP) and water storage protoplasts (WSP) were isolated from leaf tissues of diploid portulaca plants. WSP had a higher degree of endopolyploidization than MP and BSP. The ploidy distribution was also variable in different floral organs. Tetraploid plants artificially induced by colchicine treatment showed a decline in the degree of polysomaty compared to diploid plants. Tetraploid plants had more spherical leaves, a larger number of petals and lower pollen fertility than diploid plants. PMID:10936528
2000-07-28
British Library Electronic Table of Contents (United Kingdom)
Concerns for potential vulnerability to manganese (Mn) neurotoxicity during fetal and neonatal development have been raised due to increased needs for Mn for normal growth, different sources of exposure to Mn, and pharmacokinetic differences between the young and adults. A physiologically based pharmacokinetic (PBPK) model for Mn during human gestation and lactation was developed to predict Mn in fetal and neonatal brain using a parallelogram approach based upon extrapolation across life stages in rats and cross-species extrapolation to humans. Based on the rodent modeling, key physiological processes controlling Mn kinetics during gestation and lactation were incorporated, including alterations in Mn uptake, excretion, tissue-specific distributions, and placental and lactational transfer ...
2011-01-01
Physiological changes in rats after exposure to low levels of microwaves
Energy Technology Data Exchange (ETDEWEB)
The effects of exposure to sublethal levels of microwaves were studied. Young albino rats of both sexes were exposed for 60 days to 7.5-GHz microwaves (1.0-KHz square wave modulation, average power 0.6 mW/cm2) for 3 h daily. During and after microwave exposure several physiological parameters were measured in both control and exposed animals. It was found that the animals exposed to microwaves tended to eat and drink less and thus showed a smaller gain in body weight. Some of the hematological parameters and organ weights were also significantly different. It is proposed that a nonspecific stress response due to microwave exposure and mediated through the central nervous system is responsible for the observed physiological changes.
1990-08-01
Percutaneous nephrolithotomy for staghorn kidney stones in elderly patients
British Library Electronic Table of Contents (United Kingdom)
Purpose We retrospectively analyzed the results of percutaneous nephrolithotomy operations for treatment of staghorn kidney stone disease in elderly patients and compared surgical parameters and outcomes with a control group of young adult patients. Patients and method Between 2002 and 2010, 300 consecutive patients underwent percutaneous nephrolithotomy operation for treatment of staghorn kidney stone disease. Forty-five of the patients were older than 65?years and considered to be in elderly group. Thirty-seven of the patients were between the ages 18 and 36?years and considered to be the control group. Surgical parameters and outcomes were compared between groups. Results There were no significant differences between groups for stone area, operation time, difference in hemoglobin levels...
2011-01-01
Optical dating: insufficiently bleached sediments
International Nuclear Information System (INIS)
Although infrared-stimulated luminescence (IRSL) signals in feldspars can be bleached rapidly by sunlight, there could still be a small amount of IRSL signal remaining in sediment grains if they have experienced only relatively short sunlight exposure before deposition. This remaining signal results in a ''remnant dose'' stored in the grain and is important for young samples but negligible for old samples. Several methods have been introduced to detect insufficient bleaching, and some of them can provide information on the extent of the bleaching. Others can only distinguish between samples bleached for a very long time and for a short time. Empirical methods are introduced to evaluate the possible values of equivalent dose accumulated since the grains were deposited. These methods involve the analysis of the equivalent doses and the natural IRSL signals obtained using single-disc dose determination methods. (author).
1993-07-01
Ontology and law in the early Poulantzas
British Library Electronic Table of Contents (United Kingdom)
This article reviews the little examined early work of the Greek Marxist and state theorist, Nicos Poulantzas (1936-1979). In his first book, Nature du choses et droit of 1965, the young scholar developed a sociology of law culled from the insights of philosophical ontology. The article sets out the central claims of that book and reflects on its place in Poulantzass intellectual development. Drawing on Heidegger, Sartre and Marx, Poulantzas proposed a species of Natural Law theory that unified `facts' and `values' by grounding legal concepts in a theory of social praxis centred on material labour. Legal categories were thus irreducible to ahistorical essences but were, rather, expressions of mankinds struggle to realize its intrinsic freedom. As we shall see, although flawed and in key re...
2009-01-01
Nonlinear evolution of protostellar disks and light modulations in young stellar objects
International Nuclear Information System (INIS)
An evolutionary model of dynamical processes in protostellar disks is described and illustrated with graphs of typical results. The effective transport mechanisms are discussed, including thermal convection, nonaxisymmetric gravitational instabilities in the outer regions of disks, and wave propagation. Consideration is then given to the stages of dynamical evolution, FU Ori outburst phenomena, unsteady accretion-disk flows, and nonlinear feedback as a mechanism to modulate mass transfer. The simulations show that mass redistribution is determined by angular-momentum transfer, which in turn is regulated by the effective viscosity generated by convectively driven turbulence. Significant mass transfer occurs as a result of mixing of infalling material with disk gas and is affected by the tidal torque associated with the growth of nonaxisymmetric disturbances in the outer disk. The time scale for disk evolution is found to be about 1 Myr. 72 refs.
1989-10-05
Neutron star evolution and emission
This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors investigated the evolution and radiation characteristics of individual neutron stars and stellar systems. The work concentrated on phenomena where new techniques and observations are dramatically enlarging the understanding of stellar phenomena. Part of this project was a study of x-ray and gamma-ray emission from neutron stars and other compact objects. This effort included calculating the thermal x-ray emission from young neutron stars, deriving the radio and gamma-ray emission from active pulsars and modeling intense gamma-ray bursts in distant galaxies. They also measured periodic optical and infrared fluctuations from rotating neutron stars and search for high-energy TeV gamma rays from discrete celestial sources.
1997-08-01
...Shipley BD17 01274 413536 Sandra Higgins Baildon Shipley BD17 01274 530097 / 07958479176 Natasha Young Baildon Shipley BD17 01274 594272 Ann and Derick Hellewell Otley Road, Shipley, BD18 01274 586387 Zoe and Rosie Shepherd Nab Wood Drive, Shipley BD18 01274 588053 Sarah Roberts Moorview Av, Shipley BD18 01274 584283 Mandy Watkins Park Grove, Shipley BD18 01274 598372 Monica Huntley Silsden BD20 01535 658539 Carolyn Vinter Silsden BD20 01535 655359 Sharon Dunning Utley BD20 01535 603698 / 07877376414 Ellen Begbie Busy buzy bumblebees Silsden BD20 ...
Mechanical properties of SiAlON glass surface after swift heavy-ion bombardment
International Nuclear Information System (INIS)
A Y-Mg-Si-Al-O-N glass was submitted to swift heavy-ion bombardment at GANIL (Caen, France) and the influence of irradiation on the mechanical properties was studied. The mechanical properties of the glass were characterized both before and after irradiation. Changes in hardness, elastic modulus and fracture toughness of the near-surface irradiated layer were determined using indentation techniques. SRIM calculations allowed to estimate the ions penetration range and the energy deposition relative to electronic and nuclear interactions, which can be correlated to the experimental damaged depth. Meyer's hardness and Young's modulus decrease by about 30 %, while fracture toughness is increased by more than 40 %. (authors)
Locally invasive lymphangiosarcoma in a young domestic shorthair
British Library Electronic Table of Contents (United Kingdom)
A 2-year-old, female spayed, domestic shorthair cat presented to the University of Missouri-Veterinary Medical Teaching Hospital (UMC-VMTH) with an approximately 11-month history of fluid-draining pockets along her ventral thorax and axillae. The skin in these regions was erythematous, and multiple areas drained a serous to serosanguinous fluid. Fluid-filled, nodules formed along the ventrum, but these nodules disappeared as fluid drained spontaneously. Histologic assessment of skin biopsies revealed areas of vascular proliferation extending along the deep margin of the section and rare instances of invasion into the superficial dermis. These vascular channels were devoid of cells, lined by variably pleomorphic endothelial cells which had a low mitotic index. Based on the mild to moderate ...
2011-01-01
Lithium abundances of southern F, G, and K dwarfs
Energy Technology Data Exchange (ETDEWEB)
Observations are reported of the lithium feature (6708 A) in some bright southern stars, most of which are F, G, or K dwarfs. Three of these stars have been suggested as belonging to the Ursa Major Group. Two of these three have the large Li abundance and strong Ca II H and K emission expected of such young stars. The third potential Ursa Major Group member has little Li, but is also not a true kinematic member. No stars were found with abnormal (Li-6)/(Li-7) ratios, in accord with other recent analyses. Thus it appears that all stars have (Li-6)/(Li-7) near the solar/terrestrial value of 0.08. 31 references.
1985-01-01
Energy Technology Data Exchange (ETDEWEB)
A rare case of primary splenic cyst is shown in a young woman who had a left subcostal abdominal pain. Abdominal echography and CT scan revealed a cyst of the anterior aspect of the spleen. A sorologic test for hidatic disease was negative. On the basis of a presumed diagnostic of nonparasitic cyst, the patient was referred to a laparoscopic decapsulation with excision of the cysts wall not covered by splenic tissue. The patient was discharged 24 hours later. Histological report revealed epidermoid cyst. The laparoscopic approach has being recently considered an effective and less invasive alternative in the treatment of splenic diseases. We demonstrated that it should be considered for the treatment of splenic cysts present in a superficial location, with the advantage of organ preservation. (author)
2000-10-01
Internet use and online social support among same sex attracted individuals of different ages
British Library Electronic Table of Contents (United Kingdom)
The current research addressed age differences in internet use among Same Sex Attracted (SSA) individuals. In general, online communities are found to be a source of social support, especially for minority group members. However, it is unclear whether younger and older SSA people differ in their use of these communities. The present research examined age differences in use of online communities, hypothesizing that young SSA people primarily use these for social interaction and support, whereas older SSA people use online communities to seek sexual contacts. Study 1 examined age differences in motives to start using these websites. Study 2 examined age differences in use of online profiles and online social support. Results of both studies confirmed our hypotheses. Younger compared to older...
2011-01-01
International Union of Forest Research Organization 19th world congress proceedings
Energy Technology Data Exchange (ETDEWEB)
An international conference on forestry research presented papers on topics including forest mensuration, growth and yield; growth/yield relationships; design, performance, and evaluation of experiments; forest resource inventory and monitoring techniques; forest management, planning, and managerial economics; forestry and rural development in developing countries; forestry in sustainable economic development; conceptual advances in multiple-use forestry evaluations; economic evaluation of forest damages; supply and demand of roundwood and forest industry products; forestry and rural development in industrialized countries; analysis and evaluation of forest policies; forest institutions and organizations; biological and economic considerations when harvesting young thinning stands; applied sector modelling; and structural changes of the forest sector in a global perspective. Separate abstracts have been prepared for 3 papers from this conference.
1990-01-01
International Nuclear Information System (INIS)
Fly ash from Lagisza power station with addition of kaolin and calculated amount of carbon was reacted in flowing nitrogen at 1520"oC in order to obtain #beta#-sialon. The resulted powder was sintered with and without Y_2O_3 addition. Examinations show that it is possible to sinter that material without any sintering additives, however additive of Y_2O_3 decreases sintering temperature of about 100"oC. Sintering temperature influences the final mechanical properties like: flexural strength, microhardness, Young elastic modulus (E) and fracture toughness (K_I_c). (author)
2004-09-12
International Nuclear Information System (INIS)
From the first principles total energy calculations based on full-potential linear augmented plane wave method (FPLAPW), the elastic properties of XPt_3 (X=V, Cr, Mn, Fe, Co, Ni) are reported here. Theoretical values of Young's modulus, shear modulus, Poisson's ratio and Debye temperature are estimated from the computed elastic constants. From the analysis of the ratio of shear to bulk modulus, it is found that these intermetallic compounds are ductile in nature except CrPt_3, which is brittle. The calculated results are compared with other reported values.
2010-06-01
Emergency medicine in Oman: current status and future challenges
British Library Electronic Table of Contents (United Kingdom)
The Sultanate of Oman has a relatively young national health care system that could demonstrate its high performance at an international level. Emergency medicine as a specialty has developed rapidly in the country over the last decade. This has involved the parallel development of local emergency residency training, prehospital emergency care, and emergency nursing programs. This article reviews the progress of emergency care practice in this country from a general primary care system toward becoming an established specialty in hospital, prehospital, and private emergency care settings. It also describes aspects of undergraduate, postgraduate, and continuous emergency medicine education in the country. Further, a glimpse into academic emergency medicine and emergency nursing is provided. ...
2009-01-01
Elastic properties, hardness and indentation fracture toughness of #beta#-sialons
International Nuclear Information System (INIS)
Dense samples of #beta#-sialons (with z from 1 to 4) were pressuressly sintered for different time (15-240 minutes) and at relatively low temperature of 1600 C using single-phase #beta#-sialon powders synthesized by combustion nitridation. The samples were characterized using ultrasonic method for determination of elastic properties (E,G,#mu#). Also, hardness by Knoop and fracture toughness by Vickers indentation microfracture method was estimated. With increasing z number Young's modulus decreases from 293 to 179 GPa. Simultaneously Poisson ratio increases by about 30%. The highest values of hardness and fracture toughness were obtained for sialon with z equal to 1. (orig.).
1993-10-04
Effects of continuous exposure to carbon monoxide on auditory vigilance in man
Energy Technology Data Exchange (ETDEWEB)
Six different groups of non-smoking young male subjects were studied separately for 18 consecutive days each in a closed controlled-environmental human exposure chamber. Each group was subjected to a 5-day control period in fresh air followed successively by an 8-day period of continuous exposure to 50 ppm, 15 ppm or 0 ppm (control) by volume of carbon monoxide (CO) in air, and a 5-day recovery period in fresh air. The subjects performed a 1-h auditory vigilance task every day at the same time of day in a fixed qualitative, quantitative, and temporal relationship with food intake, consumption of stimulating beverages, physical activity, and sleep. It was concluded that such CO exposure, involving the continuous carriage of carboxyhaemoglobin loads up to 7%, was without significant effect on auditory vigilance.
1981-01-01
Effects of Valproic Acid on Organic Acid Metabolism in Children: A Metabolic Profiling Study
British Library Electronic Table of Contents (United Kingdom)
Young children are at increased risk for valproic acid (VPA) hepatotoxicity. Urinary organic acid profiles, as a surrogate of mitochondrial function, were obtained in children 1.9 to 17.3 years of age (n = 52) who were undergoing treatment with VPA for seizure disorders. Age-matched patients receiving treatment with carbamazepine (CBZ; n = 50) and healthy children not undergoing treatment (n = 22) served as controls. Age-related changes in organic acid profiles were observed in all three groups. Although the untreated and CBZ control groups were indistinguishable from each other with respect to the principal-component analysis (PCA) score plots of the subjects, a distinct boundary was apparent between the VPA and each of the control groups. Interindividual variability was observed in the V...
2011-01-01
Energy Technology Data Exchange (ETDEWEB)
Young rats were given a single irradiation dose (0.5, 2, 5 or 8 Gy) to the left knee-joint. The right unexposed knee-joint served as control. The animals were decapitated 1.5, 3, 7, 14 or 30 days after the irradiation. Longitudinal bone growth in the tibial epiphysis was established using tetracycline as an intravital marker. During the first 1.5 days after irradiation with 5 and 8 Gy, the growth was slightly inhibited (6-7%). Maximum growth retardation (20%) was found 7 to 14 days after irradiation with 5 and 8 Gy. No consistent effect occurred after 0.5 and 2 Gy. Between 14 to 30 days following irradiation growth was normalized.
1983-01-01
Early Years of Support Group I: Three Therapists' Views
British Library Electronic Table of Contents (United Kingdom)
This three-part article describes the early years of one of the mother-baby-children groups of the Project for Mothers, Infants, and Young Children of September 11, 2001. The goal of the group was to help prevent the effects of trauma and loss from disrupting the relationships among the mothers, their infants, and growing children. View I by Anni Bergman describes the mothers' states of minds as the group began, when they felt that their worlds had collapsed under them. View II by Sally Moskowitz focuses on the clinical experience of working in the group, transference and countertransference themes, helping the mothers and children with their mourning process, and helping the mothers' relationships to each other, their babies, older children, family, and friends. The evolution of a casual,...
2011-01-01
Early Language Learning and Literacy: Neuroscience Implications for Education
British Library Electronic Table of Contents (United Kingdom)
The last decade has produced an explosion in neuroscience research examining young children's early processing of language that has implications for education. Noninvasive, safe functional brain measurements have now been proven feasible for use with children starting at birth. In the arena of language, the neural signatures of learning can be documented at a remarkably early point in development, and these early measures predict performance in children's language and pre-reading abilities in the second, third, and fifth year of life, a finding with theoretical and educational import. There is evidence that children's early mastery of language requires learning in a social context, and this finding also has important implications for education. Evidence relating socioeconomic status (SES) ...
2011-01-01
Dating Studies of Elephant Tusks Using Accelerator Mass Spectrometry
Energy Technology Data Exchange (ETDEWEB)
A new method for determining the year of birth, the year of death, and hence, the age at death, of post-bomb and recently deceased elephants has been developed. The technique is based on Accelerator Mass Spectrometry radiocarbon analyses of small-sized samples extracted from along the length of a ge-line of an elephant tusk. The measured radiocarbon concentrations in the samples from a tusk can be compared to the {sup 14}C atmospheric bomb-pulse curve to derive the growth years of the initial and final samples from the tusk. Initial data from the application of this method to two tusks will be presented. Potentially, the method may play a significant role in wildlife management practices of African national parks. Additionally, the method may contribute to the underpinnings of efforts to define new international trade regulations, which could, in effect, decrease poaching and the killing of very young animals.
2002-10-03
Database for thermal and mechanical properties of REBaCuO bulks
International Nuclear Information System (INIS)
The thermal properties (thermal conductivity, thermal diffusivity, thermoelectric power, thermal dilatation, etc.) and the mechanical properties (Young's modulus, strength, hardness, fracture toughness, etc.) have been measured at low temperatures (4-300K) and under a high magnetic field (0-10T) for about 50 REBaCuO bulks (RE=Y, Gd, Nd, Sm, Dy, etc.). We have constructed the database of these properties and opened it on the Web site (thermal properties: http://ikebehp.mat.iwate-u.ac.jp/database.html and mechanical properties: http://paris.mech.iwate-u.ac.jp/sc-bulk/database.html). The influence of the species of RE ions, the content, size and dispersion of the RE211 (or Nd422) phase and Ag particles and the defects distribution on these properties is characterized.
2005-10-01
International Nuclear Information System (INIS)
The lower condition factors for two catfish species in water heated by effluents from APCo's Glen Lyn, Virginia plant as compared to control areas probably is not due to lack of food as evidenced by macroinvertebrate sampling and the fact that only 4.3 percent of the catfish stomachs were empty. Results suggested that young-of-the-year channel catfish were nonselectively eating food organisms present at both control and heated stations. The difference between stomach contents of flatheat catfish from the heated site and fauna available at that site indicated that fish were either moving out of the heated area to feed or were selectively feeding on organisms (particularly mayflies) which were in the substrate or drifted into the heated area. Stomach contents of the two species and distribution and abundance of the macroinvertebrate benthos community are detailed.
Challenges in conducting clinical trials in children: approaches for improving performance
British Library Electronic Table of Contents (United Kingdom)
Recent legislative changes in both Europe and the USA have increased the responsibility of drug developers to purposefully study the agents they market in children so that specific dosing recommendations can be made to assist clinicians in their use. Typically, clinicians use empirical- or experiential-based rationales for selecting the dose to use in children, generally in a manner that attempts to achieve the same dose-exposure or pharmacokinetic profile in children as in adults. However, whether this approach achieves the necessary dose exposure or exposure effect needed may not be systematically explored during off-label use. This creates the opportunity for under- or over-exposure in children, particularly in very young children (i.e., less than 2 years old) where a combination of fac...
2009-01-01
Block Talk: Spatial Language During Block Play
British Library Electronic Table of Contents (United Kingdom)
Spatial skills are a central component of intellect and show marked individual differences. There is evidence that variations in the spatial language young children hear, which directs their attention to important aspects of the spatial environment, may be one of the mechanisms that contributes to these differences. To investigate how play affects variations in language, parents and children were assigned to 1 of 3 conditions: free play with blocks, guided play, or play with preassembled structures (Study 1). Parents in the guided play condition produced significantly higher proportions of spatial talk than parents in the other two conditions, and children in the guided play condition produced significantly more spatial talk than those in the free play condition. Study 2 established baseli...
2011-01-01
Bipolar Disorder in Children and Adolescents Recognised in the UK: A Clinic-Based Study
British Library Electronic Table of Contents (United Kingdom)
Background:- Diagnoses of paediatric bipolar disorder have increased over the last two decades in the United States, where high levels of comorbidity with ADHD have also been reported. Aims:- To explore how British clinicians apply these diagnoses. Method:- We compared 378 young people under the age of 18 who received a diagnosis of bipolar disorder and/or ADHD from a large NHS mental health trust between 1992 and 2007. Results:- Children with bipolar disorder were rare in this sample (n-=-35, 1.0%), particularly under the age of 13 (n-=-9, 0.3%). Children with bipolar disorder presented more often with affective and psychotic symptoms than children with ADHD. Irritability was common in both disorders. Core ADHD symptoms were prevalent in both conditions but occurred in a greater proportio...
2011-01-01
Aluminium phosphide poisoning with esophageal stricture and tracheoesophageal fistula
British Library Electronic Table of Contents (United Kingdom)
Background Aluminium phosphide tablets popularly known, as ?celphos? is a highly toxic fumigant used as insecticide for preservation of food grains. India is an agricultural country and celphos tablets are easily available to psychologically vulnerable young people. It is swallowed with suicidal intent and death comes in minutes. Patients and methods In this series there were seven patients with tracheo esophageal complications out of 342 patients reviewed. Four patients had esophageal stricture and three had stricture plus tracheo esophageal fistulas. Types of symptoms including progressive dyshagia and extent of respiratory symptoms were evaluated. Nutrition status and success or failure of dilatation at the time of endoscopy was taken into account. The criteria for oesophageal replaceme...
2010-01-01
Final technical report for ''Frontiers in Plasma Kinetic Theory''
International Nuclear Information System (INIS)
This report summarizes the results and activities funded by this three-year award. The principal goal of this project was to determine the thermal conductivity in clusters of galaxies. Intracluster plasmas possess chaotic magnetic fields. Since charged particles are constrained to move primarily along magnetic field lines, the topology of intracluster magnetic fields slows particle diffusion relative to the non-magnetized case, thereby reducing the thermal conductivity. Our first approach to this problem was to employ the static-magnetic-field approximation. In reality, intracluster magnetic field lines are constantly moving, since they are advected by turbulent intracluster motions. The turbulent velocities, however, are much smaller than the rapid speeds of thermal electrons, which make the dominant contribution to the thermal conductivity. In the static-field approximation, one neglects turbulent motions of field lines, and calculates the diffusion coefficient of thermal electrons ...
2007-02-01
Energy Technology Data Exchange (ETDEWEB)
The aim of this case study is to analyse the socio-economic effects of forest fuel supply and use chains. Two of the four cases are rural district heating plants. In Perho, the co-operative organisation of forest owners maintains the fuel supply and operates the plant. In Ruukki, the local forestry association supplies forest chips to the plant. These medium-scale plants use small-sized trees from young thinning stands as their main fuel. The trees are felled manually. The other two cases are large power plants. Alholmens Kraft's new power plant in Pietarsaari aim to use 250 000 solid-m3 of forest chips annually. The logging residues are hauled to the plant as bales using traditional timber harvesting equipment or as bulk material. At young thinning stands the trees are harvested using an accumulating feller buncher. The Toppila I and II power plants in the city of Oulu used about 36 000 solid-m3 of forest chips. Over 300 000 solid-m3 ...
2003-07-01
Energy Technology Data Exchange (ETDEWEB)
Purpose: Reconstruction of radiation doses for the thoracoabdominal babygram and the abdomen X-ray from radiographic settings and exposure data acquired at Dr. von Hauner's Kinderspital (children's hospital of the University of Munich, DvHK) between 1976 and 2007; comparison of these dose values with values reported in the literature; recommendation of a reference dose value for the thoracoabdominal babygram. Materials and Methods: The data from all X-ray examinations performed since 1976 at DvHK were stored electronically in a database. After 30 years of data collection, the database now includes 305 107 radiological examinations (radiographs and fluoroscopies), especially 1493 thoracoabdominal babygrams and 3632 abdomen X-rays of newborns and young infants. With the computer program PAeDOS, a specific dose reconstruction algorithm was developed. Results: the entrance dose values of thoracoabdominal babygrams and abdomen X-rays in DvHK could be ...
2010-06-15
International Nuclear Information System (INIS)
Purpose: Reconstruction of radiation doses for the thoracoabdominal babygram and the abdomen X-ray from radiographic settings and exposure data acquired at Dr. von Hauner's Kinderspital (children's hospital of the University of Munich, DvHK) between 1976 and 2007; comparison of these dose values with values reported in the literature; recommendation of a reference dose value for the thoracoabdominal babygram. Materials and Methods: The data from all X-ray examinations performed since 1976 at DvHK were stored electronically in a database. After 30 years of data collection, the database now includes 305 107 radiological examinations (radiographs and fluoroscopies), especially 1493 thoracoabdominal babygrams and 3632 abdomen X-rays of newborns and young infants. With the computer program PAeDOS, a specific dose reconstruction algorithm was developed. Results: the entrance dose values of thoracoabdominal babygrams and abdomen X-rays in DvHK could be reduced in the last ...
2010-06-01
Origin of {gamma}-rays from young open clusters
Energy Technology Data Exchange (ETDEWEB)
The young open cluster Berkeley 87 was predicted to be associated with the COS B {gamma}-ray source 2CG 075+00 on the basis of the experimental evidence of the presence of a shock front around the Wolf - Rayet star ST3 placed in the inner part of the cluster. The CGRO phase-1 data confirm this identification. Protons accelerated at the shock boundary can produce {pi} deg. via p-p interactions and then {gamma}-rays. With the measured flux F{sub {gamma}} (E > 100 MeV) {approx_equal} 9x10{sup -7} ph cm{sup -2} s{sup -1} and the power-law proton spectrum with spectral index {gamma} = 2, the cosmic-ray-energy-density in the inner part ({approx} 0.8 pc radius) of Berk 87 is about 100 times greater than that in the vicinity of the Earth. We have calculated {gamma}-ray spectra expected from the decay of {pi}{sup d}eg. produced in p-p interactions. The spectra have been normalized to the observed flux of Berk 87 by using different input proton spectra. The comparison ...
1996-08-01
International Nuclear Information System (INIS)
The upper range of the requirement for methionine plus cystine in healthy adults was proposed in 1985 by FAO/WHO/UNU to be 13 mg.kg body wt-1.d-1. To explore the validity of this estimate, five healthy, young adult men were given for 7 d a diet based on an L-amino acid mixture supplying 13 mg methionine.kg-1.d-1 (87 mumol.kg-1.d-1) without cystine. Constant intravenous infusions of L-[2H3-methyl-1-13C]methionine were given on days 5 and 7 while subjects were in the fed and postabsorptive states, respectively. Estimates were made of methionine oxidation, and daily methionine balance was derived from the intake-oxidation data. For the five subjects, methionine balances were -0.9, +0.7, +3.5, -3.1, and -3.8 mg kg-1.d-1, or -6, +5, +23, -21, and -26 mumol.kg-1.d-1. These findings lead to the conclusion that the upper range of the requirement for methionine plus cystine probably exceeds 13 mg.kg-1.d-1 in healthy young adults. The implications of ...
International Nuclear Information System (INIS)
A series of Model Tests of Embedment Effect on Reactor Buildings has been carried out by the Nuclear Power Engineering Corporation (NUPEC), under the sponsorship of the Ministry of International Trade and Industry (MITI) of Japan. Reactor buildings in Japan are partially embedded in general. Therefore, it is important to know how partial embedment affects the vibration characteristics of reactor buildings relating to seismic safety. Laboratory tests were conducted using a ground model made of silicone rubber (Young's modulus 2.3x10"6 Pa, Poisson's ratio 0.484, Density 1.24x 10"3 kg/m3 , Damping ratio 0.01) and a foundation model made of aluminum shown to study the effects of embedment on soil-structure interaction with different backfill types. The ground model is a cylinder, 70 cm high and 300 cm in diameter, with pit where the parallelepiped foundation model with square plan of 30 cm x 30 cm and 18 cm high was placed. Four types of backfill of silicone rubber ...
1993-08-15
Health-hazard evaluation report HETA 88-108-2146, Asarco New Market/Young Mines, Mascot, Tennessee
Energy Technology Data Exchange (ETDEWEB)
In response to a request from the International Chemical Workers Union, Akron, Ohio, an investigation was made into possible hazardous working conditions at two American Smelting and Refining Company (SIC-1031) zinc mines (New Market and Young) in Mascot, Tennessee. Specifically, exposures to asbestos (1332214), silica (14808607), and diesel emissions were determined. At both mines overexposures were found to nitrogen-dioxide (10102440) (NO2) and coal-tar pitch volatiles. Twenty-four percent of the NO2 measurements taken were above the NIOSH recommended ceiling of 1 part per million (ppm), but none exceeded the Mine Safety and Health Administration's (MSHA) ceiling of 5ppm. Exposure to diesel particulates ranged from 0.24 to 1.06mg/cu m. None of the 52 respirable dust samples collected exceeded the calculated MSHA limits for free silica exposure. A medical evaluation was offered and 83 of the 400 current employees and one retired employee participated. ...
1991-10-01
Functional magnetic resonance imaging of the normal and abnormal visual system in early life.
DEFF Research Database (Denmark)
Functional magnetic resonance imaging (fMRI) in young children may provide information about the development of the visual cortex, and may have predictive value for later visual performance. The purpose of this study was to evaluate the usefulness of fMRI for examining cerebral processing of vision in very young infants and in infants with brain damage. We examined 15 preterm infants, 12 children suspected of having a cerebral visual impairment and 10 children with a normal visual system, all of whom were either spontaneously asleep or sedated with chloral hydrate. Cortical response to stroboscopic light stimulation could be demonstrated in all technically acceptable data sets from children with a post-menstrual age (PMA) of > 41 weeks, but not in younger infants. Children < 60 weeks PMA showed either a blood oxygenation level-dependent (BOLD) signal increase or decrease, while all older children showed a signal decrease. The activated ...
2000-01-01
Forestry-service entrepreneurs as producers of services
International Nuclear Information System (INIS)
The concept of forestry-service enterprise used in the joint study (1997-7999) by the TTS-Institute and the Finnish Forest Research Institute (Metla) refers to enterprises and co-operatives (including forest workers operating as entrepreneurs) offering services in the fields of silviculture, basic forest improvement, planning and wood-harvesting sector. Companies practicing large-scale wood-conversion and traditional forestry-machine and road haulage contractors are not included in this approach. It can be estimated that there is a total of 450 such entrepreneurs in the country Those engaged in only a minor degree in providing forestry services are not included in the figure. The nation-wide research material was collected in the form of a mail questionnaire addressed to forestry-service entrepreneurs (n=320) in the spring of 1998. Almost all forestry-service entrepreneurs provide timber felling as a service. More than half of them do planting, cleaning of young ...
Evaluation of a novel radiopacifiying agent on the physical properties of surgical spineplex.
Polymethlylmethacrylate (PMMA) is the most frequently used cement for percutaneous vertebroplasty and kyphoplasty. To aid visualisation during surgery cements are doped with radiopacifying agents such as Barium sulphate (Ba(2)SO(4)) or Zirconium Dioxide (ZiO(2)). Mounting research suggests that these agents may impair the biocompatibility of the cements. However, incorporating an alternative radiopacifier agent with excellent biocompatibility would be a significant step forward. Bioactive radiopaque glasses incorporating elements such as strontium (Sr) and zinc (Zn), known to have beneficial and therapeutic effects on bone, are of great interest in this respect. In this study, the Ba(2)SO(4) of the commercially available Spineplex was incrementally replaced with a radiopaque therapeutic glass composition. The resulting effects on cement setting time, peak isotherm, ultimate compressive strength, Young's modulus (up to 30 days cement maturation) and radiopacity were ...
2009-08-18
This study investigated whether estradiol influenced the survival of new granule neurons, independent of altering cell proliferation, in the adult rodent dentate gyrus and whether estradiol-induced changes in new neuron number relate to any observed changes in hippocampus-dependent behavior. To test whether estradiol specifically promotes the survival of new neurons we injected castrated adult male meadow voles with the cell synthesis marker bromodeoxyuridine (BrdU; 50 mg/kg) twice on day 0 and then injected either estradiol (10 microg) or vehicle for 5 consecutive days either over days 1-5, days 6-10 or days 11-15 and perfused them on day 16. Estradiol doubled the number of hippocampal BrdU-labeled neurons but only when administered during a discrete period (days 6-10; P< or =0.01) when most new neurons extend their axons [J Comp Neurol 413 (1999) 146]. To test whether the estradiol-induced increase in new neuron number was related to hippocampus-dependent behavior, males were ...
2004-01-01
Developmental cortical thinning in fetal alcohol spectrum disorders.
Regional cortical thickness was evaluated using CIVET processing of 3D T1-weighted images (i) to compare the variation in cortical thickness between 33 participants with fetal alcohol spectrum disorders (FASD) aged 6-30 years (mean age 12.3 years) versus 33 age/sex/hand-matched controls, and (ii) to examine developmental changes in cortical thickness with age from children to young adults in both groups. Significant cortical thinning was found in the participants with FASD in large areas of the bilateral middle frontal lobe, pre- and post- central areas, lateral and inferior temporal and occipital lobes compared to controls. No significant cortical thickness increases were observed for the FASD group. Cortical thinning with age in a linear model was observed in both groups, but the locations were different for each group. FASD participants showed thinning with age in the left middle frontal, bilateral precentral, bilateral precuneus and paracingulate, left inferior ...
2011-06-17
APERTURE SYNTHESIS IMAGING OF V892 Tau AND PV Cep: DISK EVOLUTION
International Nuclear Information System (INIS)
I present a study of two Herbig Ae stars that are in completely different evolutionary stages: V892 Tau and PV Cep. Using sub-arcsecond interferometric observations obtained with the Combined Array for Research in Millimeter-wave Astronomy at #lambda# = 1.3 and 2.7 mm, I have for the first time resolved their disks. I deduce that the 5 Myr old V892 Tau has a low dust opacity index #beta# = 1.1 and a disk mass of #approx#0.03 M_s_u_n. These values correspond to the growth of its dust into large, up to centimeters size, structures. In contrast, the very young (a few x10"5 yr) PV Cep has a quite high opacity index #beta# = 1.75 and a more massive disk 0.8 M_s_u_n. PV Cep has the youngest resolved disk around any Herbig Ae star. Unlike the youngest T Tauri and Class 0 stars, which contain large and processed grains, the young Herbig Ae star, PV Cep, disk contains interstellar-medium-like unprocessed dust. This suggests that PV Cep's dust evolution ...
2010-10-10
THE M-#sigma# AND M-L RELATIONS IN GALACTIC BULGES, AND DETERMINATIONS OF THEIR INTRINSIC SCATTER
International Nuclear Information System (INIS)
We derive improved versions of the relations between supermassive black hole mass (M _B_H) and host-galaxy bulge velocity dispersion (#sigma#) and luminosity (L; the M-#sigma# and M-L relations), based on 49 M _B_H measurements and 19 upper limits. Particular attention is paid to recovery of the intrinsic scatter (#epsilon#_0) in both relations. We find log(M _B_H/M _s_u_n) = #alpha# + #beta#log(#sigma#/200 km s"-"1) with (#alpha#, #beta#, #epsilon#_0) = (8.12 #+-# 0.08, 4.24 #+-# 0.41, 0.44 #+-# 0.06) for all galaxies and (#alpha#, #beta#, #epsilon#_0) = (8.23 #+-# 0.08, 3.96 #+-# 0.42, 0.31 #+-# 0.06) for ellipticals. The results for ellipticals are consistent with previous studies, but the intrinsic scatter recovered for spirals is significantly larger. The scatter inferred reinforces the need for its consideration when calculating local black hole mass function based on the M-#sigma# relation, and further implies that there may be substantial selection bias in studies of the ...
2009-06-10
THE EVOLUTION OF THE KINEMATICS OF NEBULAR SHELLS IN PLANETARY NEBULAE IN THE MILKY WAY BULGE
International Nuclear Information System (INIS)
We study the line widths in the [O III]#lambda#5007 and H#alpha# lines for two groups of planetary nebulae in the Milky Way bulge based upon spectroscopy obtained at the Observatorio Astronomico Nacional in the Sierra San Pedro Martir (OAN-SPM) using the Manchester Echelle Spectrograph. The first sample includes objects early in their evolution, having high H#beta# luminosities, but [O III]#lambda#5007/H#beta# < 3. The second sample comprises objects late in their evolution, with He II #lambda#4686/H#beta#>0.5. These planetary nebulae represent evolutionary phases preceding and following those of the objects studied by Richer et al. in 2008. Our sample of planetary nebulae with weak [O III]#lambda#5007 has a line width distribution similar to that of the expansion velocities of the envelopes of asymptotic giant branch stars and shifted to systematically lower values as compared to the less evolved objects studied by Richer et al. The sample with strong He II #lambda#4686 has a ...
2010-06-10
PROBING THE ORIGINS OF THE C IV AND Fe K? BALDWIN EFFECTS
International Nuclear Information System (INIS)
We use UV/optical and X-ray observations of 272 radio-quiet Type 1 active galactic nuclei and quasars to investigate the C IV Baldwin Effect (BEff). The UV/optical spectra are drawn from the Hubble Space Telescope, International Ultraviolet Explorer and Sloan Digital Sky Survey archives. The X-ray spectra are from the Chandra and XMM-Newton archives. We apply correlation and partial-correlation analyses to the equivalent widths (EWs), continuum monochromatic luminosities, and ?ox, which characterizes the relative X-ray to UV brightness. The EW of the C IV ?1549 emission line is correlated with both ?ox and luminosity. We find that by regressing l?(2500 A) with EW(C IV) and ?ox, we can obtain tighter correlations than by regressing l?(2500 A) with only EW(C IV). Both correlation and regression analyses imply that l?(2500 A) is not the only factor controlling the changes of EW(C IV); ?ox (or, equivalently, the soft X-ray emission) plays a fundamental role in the ...
2009-09-01
MONTE CARLO SIMULATIONS OF GLOBULAR CLUSTER EVOLUTION. V. BINARY STELLAR EVOLUTION
International Nuclear Information System (INIS)
We study the dynamical evolution of globular clusters containing primordial binaries, including full single and binary stellar evolution using our Monte Carlo cluster evolution code updated with an adaptation of the single and binary stellar evolution codes SSE and BSE from Hurley et al. We describe the modifications that we have made to the code. We present several test calculations and comparisons with existing studies to illustrate the validity of the code. We show that our code finds very good agreement with direct N-body simulations including primordial binaries and stellar evolution. We find significant differences in the evolution of the global properties of the simulated clusters using stellar evolution compared with simulations without any stellar evolution. In particular, we find that the mass loss from the stellar evolution acts as a significant energy production channel simply by reducing the total gravitational binding energy and can significantly prolong the initial core ...
2010-08-10
Long-term modulation of cosmic rays in interplanetary magnetic turbulence
Energy Technology Data Exchange (ETDEWEB)
Long-term modulation of galactic cosmic rays in interplanetary magnetic field (IMF) turbulence is a fundamental subject for understanding the connection between cosmic ray transport and solar activity. The discovery of a new cosmic ray modulation phenomenon is reported. Analysis of neutron monitor data has revealed that the difference in amplitude of the cosmic ray diurnal anisotropy for IMF sectors directed toward and away from the Sun displays a solar cycle variation. Neutron monitor data recorded at Climax, Deep River, Hyancayo, Kiel, Mt. Washington, and Swarthmore/Newark over the period 1957 to 1988 show that the amplitude difference varied between approximately 0.1 to -0.1 percent, with peaks in 1960, 1972, and 1982. A theoretical expression for this difference was derived from a three-dimensional model. Analysis also showed that the latitudinal density gradient of cosmic rays changed between 1.6 and -1.6 percent/AU with a solar cycle variation, which may ...
1989-01-01
Is the Short Distance Scale a Result of a Problem with the LMC Photometric Zero Point?
Energy Technology Data Exchange (ETDEWEB)
I present a promising route to harmonize distance measurements based on clump giants and RR Lyrae stars. This is achieved by comparing the brightness of these distance indicators in three environments: the solar neighborhood, Galactic bulge and Large Magellanic Cloud (LMC). As a result of harmonizing the distance scales in the solar neighborhood and Baade's Window, I derive the new absolute magnitude of RR Lyrae stars, M{sub v}(RR) at [Fe/H] = -1.6 (0.59 {+-} 0.05, 0.70 {+-} 0.05). Being somewhat brighter than the statistical parallax solution, but fainter than typical results of the main sequence fitting to Hipparcos data, these values of M{sub V}(RR) favor intermediate or old ages of globular clusters. Harmonizing the distance scales in the LMC and Baade's Window, I show that the most likely distance modulus to the LMC, {mu}{sub LMC} is in the range 18.24 - 18.44. The Hubble constant of about 70 km/s/Mpc reported by the HST Key Project is based ...
2004-03-29
Galactic evolution of D and "3He including stellar production of "3He
International Nuclear Information System (INIS)
New stellar models which track the production and destruction of "3He (and D) have been evolved for a range of stellar masses (0.65#<=#M/M_c_i_r_c_l_e_-_d_o_t#<=#100), metallicities (0.01#<=#Z/Z_c_i_r_c_l_e_-_d_o_t#<=#1), and initial (main-sequence) "3He mass fractions (10"-"5#<=#X_3_,_M_S#<=#10"-"3). Armed with the "3He yields from these stellar models we have followed the evolution of D and "3He using a variety of chemical evolution models with and without infall of primordial or processed material. Production of new "3He by the lower mass stars overwhelms any reasonable primordial contributions and leads to predicted abundances in the presolar nebula and/or the present interstellar medium in excess of the observationally inferred values. This result, which obtains even for zero primordial D and "3He, and was anticipated by Rood, Steigman, ampersand Tinsley is insensitive to the choice of chemical evolution model; it is driven by the large "3He yields from low-mass ...
Composition, structure and evolution of neutron stars with kaon condensates
International Nuclear Information System (INIS)
We investigate the possibility of kaon condensation in the dense interior of neutron stars through the s-wave interaction of kaons with nucleons. We include nucleon-nucleon interactions by using simple parametrizations of realistic forces, and include electrons and muons in #beta#-equilibrium. The equation of state above the condensate threshold is derived in the mean field approximation. The conditions under which kaon condensed cores undergo a transition to quark matter containing strange quarks are also established.The critical density for kaon condensation lies in the range (2.3-5.0)#rho#_0, where #rho#_0=0.16 fm"-"3 is the equilibrium density of nuclear matter. The critical density depends largely on the value of the strangeness content of the proton, the size of which is controversial. For too large a value of the strangeness content, matter with a kaon condensate is not sufficiently stiff to support the lower limit of 1.44 M_o_e_d_o_t for a neutron star. Kaon condensation ...
Central engine of quasars and AGNs: a relativistic proton radiative shock
International Nuclear Information System (INIS)
Active galactic nuclei (AGNs) and quasars (QSOs) appear to emit roughly equal energy per decade from radio to gamma-ray energies (e.g. Ramaty and Ligenfelter 1982). This argues strongly for a nonthermal radiation mechanism (see Rees 1984). In addition, statistical studies have indicated that the spectra of these objects in the IR-UV and 2 to 50 keV x-ray band, can be fitted very well with power laws of specific indices. These spectral indices do not seem to depend on the luminosity or morphology of the objects (Rothschild et al. 1983; Malkan 1984), and any theory should account for them in a basic and model independent way. If shocks accelerate relativistic protons via the first-order Fermi mechanism (e.g. Axfor 1981), the radiating electrons can be produced as secondaries throughout the source by proton-proton (p-p) collisions and pion decay, thus eliminating Compton losses (Protheroe and Kazanas 1983). As shown by Kazanas (1984), if relativistic electrons are ...
1985-08-01
Vascular plants of the Hanford Site
Energy Technology Data Exchange (ETDEWEB)
An updated listing of the vascular plants of the Hanford Site is provided, along with discussions of how humans may interact with local plants and have influenced the regional flora. Based on examinations of herbarium collections at the Westinghouse Hanford Company, Pacific Northwest Laboratory, Washington State University, and Brigham Young University, 590 vascular plant species have been identified on or near the Hanford Site. This is more than twice the number of species on previously published lists of Hanford Site vascular plants. A review of the plant species that are currently listed as endangered, threatened, sensitive, or otherwise of concern to the Washington State Natural Heritage Program and the Federal Fish and Wildlife Service is included. Color photographs of selected species are included to aid identification. Lists are provided of the Hanford Site plant species that could be used as food and medicinal sources and of those introduced to the region ...
1992-07-01
Variability of infrared stimulated luminescence properties from fractured feldspar grains
Energy Technology Data Exchange (ETDEWEB)
A series of OSL properties of fragments from split feldspar grains have been investigated. These are (1) the response to a radiation dose, (2) the recycling of corrected induced luminescence (L{sub i}/T{sub i}), (3) the corrected natural luminescence (L{sub N}/T{sub N}), (4) the corrected thermal transfer luminescence (termed herein L{sub tt}/T{sub tt}) and, (5) the rate of anomalous fading ('g'). It was found that the parameters of different parts of the same grain are the same. The relative uncertainty, at the 2 sigma level, at which we can claim that the measured parameters are correlated, is generally less than 5% but is ca 40% for the anomalous fading rate due to measurement uncertainty. For young partially bleached sediments, the result is that one could use one fragment to evaluate the equivalent dose and another to assess the contribution of thermal transfer resulting from preheating the natural luminescence.
2003-10-01
Through the collaborative efforts of undergraduates and faculty at Gettysburg and Franklin & Marshall Colleges, we present the compilation of 10 years of differential photometry for three K-type stars in the Pleiades. These young stars have rotational light curves with V-band amplitudes of a few percent (10% in the most active) due to BY Draconis-type behavior (modulation due to rotation of a star with non-uniform surface brightness). With 10 years of photometry reduced, measured, and compiled we are now in a position to probe the V-band variations in these stars for indications of the extent of brightness asymmetry in the photosphere, and characteristics of the long-term activity of these stars. These observations were acquired at the National Undergraduate Research Observatory, operated by Lowell Observatory and Northern Arizona University. This work is supported by Gettysburg College, the Pennsylvania Space Grant Consortium, Arizona Space Grant, NSF grant ...
2007-05-01
The relationship between hyperactivity and neuropsychological test performance at different age levels was examined. It was found that for young children (6 to 8 years of age, n = 90), there was no significant association between hyperactivity/attentional problems (as measured by the Hyperactivity scale of the Child Behavior Checklist) and performance on neuropsychological tasks thought to contain an attentional component (WISC-R Coding, Arithmetic, and Digit Span; WRAT Arithmetic; and the Benton Visual Retention Test). However, for older children (9 to 12 years of age, n = 92), there were significant and large negative correlations between CBC Hyperactivity scores and Coding, WRAT Arithmetic, and Benton VRT scores. Multiple regression analyses supported the above results (for Coding and WRAT Arithmetic), indicating that hyperactivity/inattention has a particularly deleterious effect on test performance (relative to same-age peers) as age increases. PMID:3361033
1988-02-01
International Nuclear Information System (INIS)
In the future even more than in the past, nuclear power will be indispensable in the present industrialized countries and in those still under development. The safe, nonpolluting, and economic supply of energy to mankind in the future includes so many different problems that the technology of the high-temperature reactor at its present level of development, and with the possibilities is offers above and beyond those provided by other, established, technologies, does not have to mark the end of some old line of development, but rather should be seen as the starting point of a development offering promise for the future. It is for this very reason that the extensive, valuable knowledge and experience accumulated in the construction, operation, and decommissioning of the AVR and THTR plants, the development of the HTR module and other variants and, last, but not least, the valuable results of projects such as PNP, NFE, and HHT, must be preserved at the research centers and with former ...
The Star Clusters in the Irregular Galaxy NGC 4449
We examine the star clusters in the irregular galaxy NGC 4449. We use a near-infrared spectrum and broad-band images taken with the HST to place a limit of 8--15 Myrs on the age of the bright central ojbect in NGC 4449. Its luminosity and size suggest that it is comparable to young super star clusters. However, there is a peculiar nucleated-bar structure at the center of this star cluster, and we suggest that this structure is debris from the interaction that has produced the counter-rotating gas systems and extended gas streamers in the galaxy. From the images we identify 60 other candidate compact star clusters in NGC 4449. Fourteen of these could be background elliptical galaxies or old globular star clusters. Of the star clusters, three, in addition to the central object, are potentially super star clusters, and many others are comparable to the populous clusters found in the LMC. The star clusters span a large range in ages with no obvious peak in cluster ...
2000-01-01
The Local Environment of the FUor-like Objects AR 6A and 6B
We present new 12CO J=3-2 and HCN J=3-2 molecular line maps of the region surrounding the young star AR 6 using the 15 metre James Clerk Maxwell Telescope. AR 6 was previously found to be a double source with both components exhibiting several characteristics of FU Orionis (FUor) eruptive variable stars. Our data indicates that AR 6, like FU Orionis itself, does not possess a CO outflow and likewise, does not show evidence for large amounts of molecular g as in its circumstellar environment. We conclude that from the near-IR to the sub-mm, AR 6 is similar to FU Orionis in several respects. We interpret the lack of significant dust and molecular gas in the circumstellar environment of AR 6, together with the large near-IR thermal excess, as evidence that the sources have exhausted their natal envelopes, that they have at least small hot circumstellar disks, and that they are more evolved than Class I protostars. This, in itself, suggests that, since FUor eruptions ...
2008-01-01
The Effects of Capitation on Outpatient Mental Health Episodes of Children
We analyzed the effects of the Colorado Medicaid Capitation Program on the duration and services of over 21,000 outpatient mental health episodes for young children. The study spanned a three year period before and after capitation was implemented, and compared episodes of outpatient care for children from 14 capitated Community Mental Health Centers (CMHCs) with those from three CMHCs that remained fee-for-service. Proportional hazards regressions revealed that capitation resulted in an increase in outpatient episode duration, over and above similar effects for the comparison fee-for-service episodes. The hypothesis that there were longer capitated episodes for children who were hospitalized was not supported. Children with behavioral and anxiety disorders had longer capitated episodes. Service intensity decreased over time in the managed care sites. Changes in case mix may have had an impact on changes in episode duration and service intensity. That outpatient ...
2006-02-01
Energy Technology Data Exchange (ETDEWEB)
Thermal and mechanical properties for geothermal formations are tabulated for a range of temperatures and stress conditions. Data was obtained from the technical literature and direct contacts with industry. Thermal properties include heat capacity, conductivity, and diffusivity. Undisturbed geothermal profiles are also presented. Mechanical properties include Youngs modulus and Poisson ratio. GEOTEMP thermal simulations of drilling, production and injection are reported for two geothermal regions, the hot dry rock area near Los Alamos and the East Mesa field in the Imperial Valley. Actual drilling, production, and injection histories are simulated. Results are documented in the form of printed GEOTEMP output and plots of temperatures versus depth, radius, and time. Discussion and interpretation of the results are presented for drilling and well completion design to determine: wellbore temperatures during drilling as a function of depth; bit temperatures over the ...
1981-07-01
Synthesis and characterization of #beta#-SiAlON with a rare earth concentrate as sintering aid
International Nuclear Information System (INIS)
Silicon nitride-based ceramics behavior is strongly influenced by microstructural parameters, which, in turn are determined by chosen densification method. Highly covalent Si-N bond hind are the silicon nitride densification. Therefore, metal oxides are used in order to get high density. However, such oxides must be carefully selected, because they affect the general macroscopic properties of sintered bodies. In the present work, the viability of rare earth concentrate use to produce #beta#--Si_6_-_xAl_xO_xN_8_-_x and its effect on mechanical properties of the sintering ceramics are studied. Additive composition, heating rate, soaking time and sintering temperature were took as variables. Hardness, fracture toughness, Young's modulus and flexural strength were investigated. Lattice parameter compositional dependence and secondary phases crystallized after past-sintering heat treatment were also determined. The results show that rare earth concentrate works very ...
Surface treatment of Ti-6Al-4V alloy by rf plasma nitriding
Energy Technology Data Exchange (ETDEWEB)
The Ti-6Al-4V alloy was treated by inductively coupled rf plasma nitriding. The effects of plasma-processing time in the range of 5-35 min on the microstructure and the mechanical properties of the plasma-nitrided Ti-6Al-4V samples were studied. The plasma power input was adjusted at 450 W and pure N{sub 2} gas was introduced to establish a treatment pressure of 8.0-8.4 x 10{sup -2} mbar. The characteristics of the nitrided layers have been investigated by microhardness testing, surface roughness measurements, optical microscopy, and x-ray diffraction. The results show that the surface microhardness increases as the plasma-processing time increases to reach 2000 HV0.1 at a plasma-processing time of 35 min. A high nitriding rate of 2.81 {mu}m{sup 2} s{sup -1} at a plasma-processing time of 25 min was achieved. The formation of the hard phases TiN, Ti{sub 2}N, and Ti(N) in the Ti-6Al-4V surfaces are found to be the reason for the increased microhardness. Surface energy, yield strength ...
2007-10-03
Surface treatment of Ti-6Al-4V alloy by rf plasma nitriding
International Nuclear Information System (INIS)
The Ti-6Al-4V alloy was treated by inductively coupled rf plasma nitriding. The effects of plasma-processing time in the range of 5-35 min on the microstructure and the mechanical properties of the plasma-nitrided Ti-6Al-4V samples were studied. The plasma power input was adjusted at 450 W and pure N_2 gas was introduced to establish a treatment pressure of 8.0-8.4 x 10"-"2 mbar. The characteristics of the nitrided layers have been investigated by microhardness testing, surface roughness measurements, optical microscopy, and x-ray diffraction. The results show that the surface microhardness increases as the plasma-processing time increases to reach 2000 HV0.1 at a plasma-processing time of 35 min. A high nitriding rate of 2.81 #mu#m"2 s"-"1 at a plasma-processing time of 25 min was achieved. The formation of the hard phases TiN, Ti_2N, and Ti(N) in the Ti-6Al-4V surfaces are found to be the reason for the increased microhardness. Surface energy, yield strength and ...
2007-10-03
Student Concern and Potential Action Regarding Nuclear Threat.
Throughout their history, Americans have believed that citizens' fulfillment of their individual duties in a participatory democracy is at least partly met through the forming of groups around important societal issues. Given the complex nature of political socialization, this study investigated identifiable determinants of social action that might be used to advantage in educating young people for citizenship in a democracy. This study attempted to differentiate among junior high, high school and college students (N=517) who were inclined and not inclined to act on their concerns about nuclear threat with selected demographic, psychological, political, and educational variables. The results of a discriminant functional analysis indicated that in comparison with the non-action group, students in the action group were characterized by reporting less trust in government, more exposure to sources of nuclear war information, more political knowledge, a more liberal ...
1990-08-01
Stellar Populations of Lyman-alpha Emitters at z=4.86: A Comparison to $z\\sim5$ LBGs
(abridged) We present a study of stellar population of LAEs at z=4.86 in GOODS-N and its flanking field. With the publicly available IRAC data in GOODS-N and further IRAC observations in the flanking fields, we select five LAEs which are not contaminated by neighboring objects in IRAC images and construct their observed SEDs with I_c, z', IRAC 3.6micron, and 4.5micron band photometry. The SEDs cover the rest-frame UV to optical wavelengths. We derive stellar masses, ages, color excesses, and star formation rates of five LAEs using SED fitting method. Assuming the constant star formation history, we find that the stellar masses range from 10^8 to $10^{10} Msun with the median value of 2.5x10^9 Msun. The derived ages range from very young ages (7.4 Myr) to 437 Myr with a median age of 25 Myr. The color excess E(B-V) are between 0.1-0.4 mag. Star formation rates are 55-209 Msun/yr. A comparison of the stellar populations is made between three LAEs and 88 LBGs selected ...
2010-01-01
International Nuclear Information System (INIS)
Iron is an essential micronutrient. As an integral part of hemoglobin, it is essential for the transport of oxygen in blood to the tissues. It is an important component of cytochromes and other tissue enzymes that are critical for cellular respiration and of myoglobin that helps maintain oxygen reserve in the muscle. It is also involved in the normal functioning of the immune function, and in the synthesis of steroid hormones and bile acids. There are serious functional consequences to iron deficiency and iron deficiency anemia (IDA) in the human body. The deleterious effects include increased morbidity, preterm delivery, low birth weight, delayed cognitive development, lowered cellular immunity and reduced physical work capacity. However, iron deficiency and IDA remain the world's most common deficiency disease in the 21st century. Recent estimates of people affected with iron deficiency and IDA are 3.5 billion. Iron deficiency anemia is most prevalent and severe in women and children ...
2002-06-24
Solid-pseudopapillary tumor of the pancreas in a 13-year-old girl - case report
International Nuclear Information System (INIS)
The solid-pseudopapillary tumor (SPT) of the pancreas is a rare type of exocrine pancreatic neoplasm. SPT predominantly affects young women and female children, and is usually discovered incidentally. This tumor is generally benign with a low incidence of malignancy. A 13-year-old girl was admitted to the hospital with a few weeks' history of mild abdominal pain and jaundice. On physical examination, there was no palpable mass. The laboratory tests showed increased SR, CRP, high bilirubin, amylase and lipase serum levels. Ultrasound imaging revealed a solid lesion in the region of the pancreatic head. On MRI, precise tumor localization in the head of the pancreas with pancreatic duct dilatation and compression of the common bile duct were visualized. Pancreaticoduodenectomy and cholecystectomy was performed with good clinical outcome. Microscopic and immunohistochemical studies indicated that tumor cells were typical of SPT without any signs of malignancy. After ...
British Library Electronic Table of Contents (United Kingdom)
We hypothesized that I kappa B kinase (IKK)-mediated nuclear factor kappa B and forkhead BoxO3a phosphorylation will be associated with age-related endothelial dysfunction. Endothelium-dependent dilation and aortic protein expression/phosphorylation were determined in young and old male B6D2F1 mice and old mice treated with the IKK inhibitor, salicylate. IKK activation was greater in old mice and was associated with greater nitrotyrosine and cytokines. Endothelium-dependent dilation, nitric oxide (NO), and endothelial NO synthase phosphorylation were lower in old mice. Endothelium-dependent dilation and NO bioavailability were restored by a superoxide dismutase mimetic. Nuclear factor kappa B and forkhead BoxO3a phosphorylation were greater in old and were associated with increased express...
2011-01-01
Role of limited cell replicative capacity in pathological age change. A review
Energy Technology Data Exchange (ETDEWEB)
Physiological functions are carried out by differentiated cells, with finite lifespans, which age and need to be replaced. In young individuals, tissue functions are sustained at optimal levels because cellular dysfunction and cell loss are balanced by the emergence of newly differentiated cells as stem cells and their partially differentiated descendants replicate. However, with the passage of time the mitotic rates of these cells diminish. Eventually, replications occur too infrequently to offset the loss. It is at this point that the tissue begins to show structural changes and declining function which, as they become pervasive, are identified as ageing. In this paper the theory is set forth that: (1) Diminishing mitotic activity in older tissues results from limited stem cell replicative capacity. (2) All stem cells, regardless of tissue, exhibit similar replicative patterns over time, progressing from the actively proliferating to the nonproliferating state. ...
1982-01-01
British Library Electronic Table of Contents (United Kingdom)
Abstract Turnip (Brassica rapa L.) plants were grown at adequate (25 mmol L-1) or low (<2.5 mmol L-1) boron (B) supply in nutrient solution for 1 month. The shoot and root dry weight was inhibited by up to 77% and 45%, respectively, in response to low B supply. The results of a retranslocation experiment showed that loaded B in the mature leaves was depleted rapidly during the experimental period and that this B was retranslocated to younger leaves as judged by B depletion from mature leaves simultaneously with the appearance of B in new leaves. Up to 89% of the B content of mature leaves was lost during 4 weeks of growth under B-deficient conditions. In addition, in B-deficient plants, a greater proportion of the total plant B was allocated to young leaves compared with B-sufficient plant...
2010-01-01
Energy Technology Data Exchange (ETDEWEB)
In order to design roof bolting systems safely and economically, it is essential to understand the flexural behaviour of the immediate roof. Based on the strata sequence, the strata in the immediate roof are divided into three types. The flexural behaviour of the three strata types are investigated in terms of the following effects: roof span, horizontal stress, thickness and Young's modulus of the lowest strata. The suspension reinforcement mechanism is analysed using beam-column theory. The equations for the maximum bending stress, deflection and transferred bolt load for the bolted strata are derived. In the analysis, the bolt load is assumed to be a point load and a horizontal stress is uniformly applied to each stratum. The friction reinforcement mechanism is also investigated. The major function of roof bolting in this case is to create frictional resistance by tensioning the roof bolts so that the individual layers are combined into one single thick ...
1985-05-01
Patterns of photometric and chromospheric variation among Sun-like stars: A 20-year perspective
We examine patterns of variation of 32 primarily main sequence stars, extending our previous 7-12 year time series to 13-20 years by combining b, y data from Lowell Observatory with similar data from Fairborn Observatory. Parallel chromospheric Ca II H and K emission data from the Mount Wilson Observatory span the entire interval. The extended data strengthen the relationship between chromospheric and photometric variation derived previously. Twenty-seven stars are deemed variable. On a year-to-year timescale young active stars become fainter when their Ca II emission increases while older less active stars such as the Sun become brighter when their Ca II emission increases. The Sun's total irradiance variation, scaled to the b and y filter photometry, still appears to be somewhat smaller than stars in our limited sample with similar mean chromospheric activity, but we now regard this discrepancy as probably due mainly to our limited stellar sample
2007-01-01
Ontogeny of accidental wetlands and hydric soil development in surface mined landscapes
Energy Technology Data Exchange (ETDEWEB)
Reducing conditions are periodically present in hydric soils and are essential for chemical processes that support wetland functions and values. Indicators of these conditions, i.e., redoximorphic features, can be useful in determining the presence of a hydric soil. However, young wetlands, i.e., those recently formed, may not possess reducing conditions and/or may not exhibit redoximorphic features. Few studies have addressed the time needed for hydric soil development. In this study, we present data on redoximorphic features, including chroma and oxidized rhizospheres, gathered from two sets of wetlands in southwestern Virginia, including (1) constructed wetlands that are 3 years old and (2) accidental wetlands that are 10 to 30 years old. Under conditions described for these sites, there is strong evidence that discernable redoximorphic features form in accidental wetlands within 10 years, but not within 3 years in constructed wetlands. Since accidental wetlands ...
1996-12-31
New dimensions in our understanding of the human health effects of environmental pollutants
Energy Technology Data Exchange (ETDEWEB)
The term {open_quotes}hazardous{close_quotes} waste is used primarily in reference to potential hazards to human health and, to a lesser decree, hazards to wildlife and the ecosystem. Many of the chemicals associated with hazardous waste sites are also widely distributed throughout the environment; therefore, the health hazards associated with hazardous waste sites are not different from those associated with general environmental contamination. Until recently, it was generally assumed that cancer was the human disease of greatest concern associated with toxic chemicals. In fact, most governmental regulations related to exposure are designed on the basis of presumed cancer risks. Since the evidence that hazardous chemicals can cause cancer is strong, it is appropriate to be concerned about cancer risk. Recent evidence, however, has triggered a reevaluation of the assumption that only cancer is of concern. New evidence suggests that noncancer endpoints may occur more frequently than ...
1996-12-31
Nanomechanical properties of vimentin intermediate filament dimers
International Nuclear Information System (INIS)
The cell's cytoskeleton, providing the cell with structure and shape, consists of a complex array of structural proteins, including microtubules, microfilaments and intermediate filaments. Intermediate filaments play a crucial role in mechanotransduction and in providing mechanical stability to cells, in particular under large deformation. By utilizing molecular simulation, here we report a nanomechanical analysis of vimentin intermediate filament dimers, the basic building blocks of intermediate filaments. We describe a detailed analysis of the mechanical properties and associated deformation mechanisms, and find that mechanical stretch induces a transition from alpha-helices to beta-sheets, a phenomenon known as alpha-beta transition. A comparison of the Young's modulus predicted from simulation with experimental measurements is provided, and good agreement is found. We present an analysis of structural changes during deformation, domain unfolding patterns, rate ...
2009-10-21
British Library Electronic Table of Contents (United Kingdom)
The effect of Mo addition on the glass-forming ability (GFA), magnetic properties, mechanical properties and corrosion resistance of (Fe0.76Si0.096B0.084P0.06)100-xMox (x=0, 2, 4 and 6at.%) bulk glassy alloys (BGAs) with high Fe contents was investigated. The 2at.% Mo addition makes the alloy composition approach towards a eutectic point, which could result in an increase in the GFA. The BGA rod with diameters up to 3.5mm was produced by copper mold casting. These BGAs exhibit a rather high saturation magnetization of 0.98-1.51T and lower coercive force of 1.7-2.1A/m. A significant improvement in corrosion resistance was observed with microalloying Mo element in 1N H2SO4 solution. Furthermore, these Fe-based BGAs show super-high strength of ~3.3GPa and Young's modulus of 200GPa.
2011-01-01
Mechanical property of superplastic-deformed ceramics by micro-indentation method
Energy Technology Data Exchange (ETDEWEB)
A neutron irradiation test on superplastic ceramic materials at high temperature has been proposed as an innovative basic research on high-temperature engineering using the High Temperature Engineering Test Reactor (HTTR). We investigated mechanical properties, such as the hardness and Young's modulus, of ceramic specimens after superplastic deformation. The tested material was 3Y-TZP (3mol% Yttria stabilized Tetragonal Zirconia Polycrystal) which is one of the representative superplastic ceramics. The properties were measured by a microindentation method. We also studied the relationship between crystal microstructures and the mechanical properties of deformed 3Y-TZP by scanning electron microscope (SEM). The indentation test showed that the mechanical properties of the specimens were reduced to about 1/2 by 30% deformation and to about 1/4 by 150% deformation. The SEM images showed that average grain size and deviation of grain size of each specimen ...
2001-03-01
Understanding the influence of interfacial structures on the nanoarchitecture mechanical properties is of particular importance for its mechanical applications. Due to a small size of constituting nanostructural units and a consequently high volume ratio of such interfacial regions, this question becomes crucial for the overall mechanical performance. Boron nitride bamboo-like nanotubes, called hereafter boron nitride nanobamboos (BNNBs), are composed of short BN nanotubular segments with specific interfaces at the bamboo-shaped joints. In this work, the mechanical properties of such structures are investigated by using direct in situ transmission electron microscopy tensile tests and molecular dynamics simulations. The mechanical properties and deformation behaviors are correlated with the interfacial structure under atomic resolution, and a geometry strengthening effect is clearly demonstrated. Due to the interlocked joint interfacial structures and compressive interfacial stresses, ...
2011-08-10
Influence of animal age upon antioxidant-modified UV carcinogenesis
International Nuclear Information System (INIS)
Studies were undertaken to examine the effects of animal age on the anticarcinogenic properties of antioxidants. Female hairless mice, 2.5, 4.5 and 9.5 months of age, were subjected to daily irradiation from Westinghouse BZS-WLG lamps for 19 weeks. Experimental groups of animals were maintained on a commercial rodent meal supplemented with a 2% (w/w) antioxidant mixture. Control groups received only the meal. Tumour latency, expressed as median time to tumor development, was significantly greater for all age groups receiving antioxidants than for their similarly aged controls. However, the response to antioxidants appeared to decrease with age and the antioxidant effect was significantly less in the 9.5 month-old group than in the 2.5 month-old group. Likewise, the two youngest groups receiving antioxidants demonstrated a significantly fewer number of tumors per animal. It is concluded that animal age influences the degree of photoprotection provided by antioxidants. Whether this ...
Individual differences and weight bias: Do people with an anti-fat bias have a pro-thin bias?
While levels of weight bias vary among individuals, it is not clear why one person possesses stronger anti-fat attitudes than another person. This investigation examined whether individual differences commonly associated with greater anti-fat bias are also associated with a greater preference for thinness among people of varying levels of weight. Young adults (62% women; 84% Caucasian) recruited from psychology classes (N=308) rated four male and female figures with approximate BMIs of 18.5, 25, 30, and 40, on measures of dislike and personality characteristics and completed measures assessing weight controllability, attitudes toward the obese, and perceptual reliance. Greater negative attitudes, weight controllability beliefs, and perceptual reliance were positively associated with greater dislike and negative personality attributes among obese/severely obese figures, but inversely related among low normal weight figures. Individuals who judge others based on ...
2010-01-20
HD 100453: A Link Between Gas-Rich Protoplanetary Disks and Gas-Poor Debris Disks
HD 100453 has an IR spectral energy distribution (SED) which can be fit with a power-law plus a blackbody. Previous analysis of the SED suggests that the system is a young Herbig Ae star with a gas-rich, flared disk. We reexamine the evolutionary state of the HD 100453 system by refining its age (based on a candidate low-mass companion) and by examining limits on the disk extent, mass accretion rate, and gas content of the disk environment. We confirm that HD 100453B is a common proper motion companion to HD 100453A, with a spectral type of M4.0V - M4.5V, and derive an age of 10 +/- 2 Myr. We find no evidence of mass accretion onto the star. Chandra ACIS-S imagery shows that the Herbig Ae star has L_X/L_Bol and an X-ray spectrum similar to non-accreting Beta Pic Moving Group early F stars. Moreover, the disk lacks the conspicuous Fe II emission and excess FUV continuum seen in spectra of actively accreting Herbig Ae stars, and from the FUV continuum, we find the ...
2009-01-01
Geochemical study on origin of natural gases in Japanese oil and gas fields
Energy Technology Data Exchange (ETDEWEB)
The origin of natural gas in the Japanese oil and gas fields are geochemically studied. Samples are taken from structural natural gas, surface gas seepage, water-dissolved natural gas and coal-field gas of the Japan Sea coast area. The origins of primary hydrocarbons are classified into bacteria gas and thermogenic gas, the latter being subclassified into gas in oil production zone with the per million deviation of the carbon isotope (/sup 13/C/sup 1/) of methane less than -35 and those gases with maturity higher than this. Surface gas seepage is subjected to migration and bacterial oxidation. Coal gas is similar to oil gas. The CO/sub 2/ concentration is 0 - 2% and /sup 13/CO/sub 2/ deviations from -30 - +30. The origin can be barely estimated from the isotopic composition because of the wide secondary change in the composition. The origin and migration of gas from the gas field of northern Niigata are not similar to those in the southern area, which consist of a thermal decomposition ...
1988-05-01
Further evidence supporting the concurrent influence of aflatoxin and manganese
Energy Technology Data Exchange (ETDEWEB)
Trace elements, including manganese may afford protection from deleterious effects of aflatoxin. Young male Fischer rats received ip injections of aflatoxin B1 (AFB1) in dimethyl sulfoxide (DMSO), 1 mg/kg, 2 mg/kg or 4 mg/kg. Control groups received DMSO ip or no injection. All animals were intubated with 3 microCi of (/sup 54/Mn)-MnCl/sub 2/ 12 hr post-injection. Sacrifice occurred 72 hr after gavage of the radiolabel. All tested levels of AFB1 affected the loss of total body radioactivity. This response was observed within 12 hr when toxin-treated groups excreted almost 4 times more counts than controls. From 12-36 hr following radiolabel administration, AFB1 appeared to enhance excretion; by 72 hr, toxin-treated animals (especially those receiving higher doses) appeared to conserve the metal. Aflatoxicosis manifested itself through reduced body weight gain. The data provide support evidence that Mn and AFB1 biointeract.
1987-04-01
Energy Technology Data Exchange (ETDEWEB)
In order to clarify the alkali-resistance of fibers to be utilized as reinforcing materials for concrete, such as glass fiber, Aramid fiber, and carbon fiber, accelerated aging tests in alkaline solution were conducted. In detail, the degree of degradation of the fracture strength and Young's modulus were investigated through static tensile strength tests after soaking in alkaline solution of these fibers and then the mechanism of degradation was examined by observation using a scanning electron microscope. The conclusion obtained was as follows. Glass fiber was easily degraded in the alkaline solution and the progress of degradation was simulated quantitatively by the method proposed in this paper, which was based on a diffusion theory. Both Aramid fiber and carbon fiber showed a significant alkali-resistance without degrading. The reaction of glass fiber with alkaline solution proceeded uniformly from the surface of glass fiber into the inner direction ...
1994-05-20
In the present political climate, politicians are singling out children's programs and services for budget cuts. The need for teacher education programs to prepare early childhood teachers as children's advocates is becoming ever more evident. For years, the National Association for the Education of Young Children has called for greater involvement of early childhood educators as advocates for programs and services that promote children's health and education. In teacher education programs, however, this call has largely gone unheeded. The purpose of this article is to discuss the importance of involving teacher candidates in advocacy activities and policy research, the obstacles that teacher educators can face when incorporating advocacy components into their teacher education courses and programs, and resources and strategies they can use. This discussion builds upon a motivation-obstacles-resources framework developed for adoption of innovative practices ...
2003-12-01
Effect of vitamin C on copper retention in young men
International Nuclear Information System (INIS)
Previous work suggests that supplemental ascorbic acid (AA) may inhibit intestinal copper absorption by stabilizing the less absorbable cuprous state. The authors studied copper absorption in healthy men (age 19-32) fed a constant diet with different amounts of ascorbic acid supplements. The 6 men were confined to a metabolic unit for the entire 14 week study. The basal diet consisted of a 7 day rotating menu which provided an average of 2.1 mg Cu/d and was adequate in all other nutrients except AA (5 mg/d). The basal diet was supplemented with either zero, 60, or 600 mg of AA daily, added to grape juice and consumed at each meal. All feces were collected. Blood was taken weekly for monitoring AA and copper status. Copper absorption was determined by both balance and "6"5Cu stable isotope techniques. As determined by fecal Cu excretion, varying intakes of AA between 0.1 to 10 times the RDA had no significant effect on copper retention. This is consistent with the lack of change in ...
1986-04-13
Coir fibers received three treatments, namely washing with water, alkali treatment (mercerization) and bleaching. Treated fibers were incorporated in starch/ethylene vinyl alcohol copolymers (EVOH) blends. Mechanical and thermal properties of starch/EVOH/coir biocomposites were evaluated. Fiber morphology and the fiber/matrix interface were further characterized by scanning electron microscopy (SEM). All treatments produced surface modifications and improved the thermal stability of the fibers and consequently of the composites. The best results were obtained for mercerized fibers where the tensile strength was increased by about 53% as compared to the composites with untreated fibers, and about 33.3% as compared to the composites without fibers. The mercerization improved fiber-matrix adhesion, allowing an efficient stress transfer from the matrix to the fibers. The increased adhesion between fiber and matrix was also observed by SEM. Treatment with water also improved values of ...
2009-06-26
Disturbed tooth formation by /sup 60/Co-gamma-ray radiation
Energy Technology Data Exchange (ETDEWEB)
The molar of guinea pigs was irradiated with /sup 60/Co-..gamma.. ray for daily observations of the manifestation of disturbed tooth formation by microradiography and the time registration by tetracycline-labelling. Irradiation first injured young blast cells of the dentin in the growth phase, dental pulp cells, and cells of the enamel. The portion composed of injured cells formed a depressed ''constriction'' from the dental pulp side toward the border between the enamel and dentin. The cells of the enamel injured by irradiation in the growth phase later formed a very thin irregular stroma. In contrast, cells in the differentiation or subsequent phase at the time of irradiation and cells probably having started to grow after irradiation proceeded with formation of a normal stroma and calcification. No uniform relation was obtained between the histological staining of the organic stroma of normal or abnormal dentin and ...
1982-02-01
Different Evolutionary Stages in the Massive Star Forming Region S255 Complex
To understand evolutionary and environmental effects during the formation of high-mass stars, we observed three regions of massive star formation at different evolutionary stages that reside in the same natal molecular cloud. Methods. The three regions S255IR, S255N and S255S were observed at 1.3 mm with the Submillimeter Array (SMA) and followup short spacing information was obtained with the IRAM 30m telescope. Near infrared (NIR) H + K-band spectra and continuum observations were taken for S255IR with VLT-SINFONI to study the different stellar populations in this region. The combination of millimeter (mm) and near infrared data allow us to characterize different stellar populations within the young forming cluster in detail. While we find multiple mm continuum sources toward all regions, their outflow, disk and chemical properties vary considerably. The most evolved source S255IR exhibits a collimated bipolar outflow visible in CO and H2 emission, the outflows ...
2010-01-01
British Library Electronic Table of Contents (United Kingdom)
Soils of arid regions of Central Asia contain salts of different types that may differentially affect seed germination and plant development. We studied effect of NaCl, Na2SO4, 2NaCl + KCl + CaCl2 and 2Na2SO4+K2SO4+MgSO4 on germination of Kochia prostrata and Kochia scoparia seeds under a range of concentrations from 0.5 to 5% and at two constant temperature regimes +22 degrees C and +6 degrees C. The observed salt tolerance limit of germination at constant temperature +22 degrees C for both species was 5-6%, while at low temperature (+6 degrees C) this limit was 2%. The salt tolerance of young plants (before flowering) was 3% for NaCl. Low concentrations of sulfuric and mixed salts had a stimulating effect on seed germination in K. prostrata. Despite similarity of salt-tolerance limits...
2011-01-01
Carbon pools and flux in the forests of Korea
Energy Technology Data Exchange (ETDEWEB)
This paper describes the estimated the rate of carbon accumulation in the woody biomass and total carbon storage in the forests including trees, soil and litter in Korea. The relevant data come from the Statistical Yearbook of Forestry and major results of the studies on forest biomass in Korea. Most of the forests, which has been denuded or degraded during the 2nd World War and the Korean War, were recovered through ``Reforestation Project(1973-1987)`` and natural regeneration. So, now they are mostly young secondary forests and grow rapidly. Total carbon removal by forests is estimated at 8.1 million tonnes of carbon(MtC) and the carbon emission by commercial harvesting at 0.9 MtC. therefore, the forests in Korea play an essential role as a net carbon sink. The annul net carbon removal is 7.2 MtC and accounts for about 11.0% of total carbon emissions in energy sector of Korea. The carbon storage in the forests is 589.9 MtC, 22.4% of that stored in trees, 64.1% in ...
1998-04-01
Carbon in boreal coniferous forest soil
Energy Technology Data Exchange (ETDEWEB)
The working hypothesis of the research was that the soil of boreal forests is a large carbon store and the amount of C is still increasing in young soils, like in the forest soils of Finland, which makes these soils important sinks for atmospheric CO{sub 2}. Since the processes defining the soil C balance, primary production of plants and decomposition, are dependent on environmental factors and site properties, it was assumed that the organic carbon pool in the soil is also dependent on the same factors. The soil C store is therefore likely to change in response to climatic warming. The aim of this research was to estimate the C balance of forest soil in Finland and predict changes in the balance in response to changes in climatic conditions. To achieve the aim (1) intensive empirical experimentation on the density of C in different pools in the soil and on fluxes between the pools was done was done, (2) the effect of site fertility and climate on the amount and ...
1996-12-31
International Nuclear Information System (INIS)
The effect of a carbohydrate, a 20% protein, or a carbohydrate +0.3% tryptophan TRP breakfast on plasma large neutral amino acid ratio was studied in 6 healthy men. The carbohydrate-rich meal produced shifts in plasma amino acid concentrations such that plasma TRP/LNAA ratios increased from 0.13 to 0.15 (p<0.04) and the protein meal decreased the ratio from 0.14 to 0.11 (p<0.04) after 1 hour. Addition of 0.3% TRP to the carbohydrate-rich meal increased plasma TRP/LNAA ratios more than 2-fold. The TRP containing meal was thus the only one likely to influence brain 5-HT synthesis, although the difference between the plasma TRP/LNAA ratios after carbohydrate and protein breakfasts suggests that the brain may distinguish, by synthesizing more or less 5-HT, the composition of breakfast meals. (Author).
Postresection villus hyperplasia is a major compensatory mechanism in the short-bowel patient. Substances capable of augmenting postresection mucosal hyperplasia could have therapeutic implications. Human growth hormone (hGH) and human growth hormone releasing factor (hGHRF) stimulate growth of the gastrointestinal tract; however, the diabetogenic actions of growth hormone limit its usefulness in clinical practice. Plerocercoid larvae of the tapeworm Spirometra mansonoides produce an analog of hGH void of diabetogenic side effects. We assessed effects of plerocercoid growth factor (PGF) on mucosal adaptation following 70% proximal jejunoileal resection in young rats. Mucosal weight, DNA, protein, and total sucrase activity per centimeter of bowel were increased in resected PGF-treated animals compared to resected controls. We conclude PGF augments intrinsic postresection mucosal hyperplasia following extensive intestinal resection. PMID:3665682
1987-11-01
Aging, tumor suppression and cancer: High-wire act!
Energy Technology Data Exchange (ETDEWEB)
Evolutionary theory holds that aging is a consequence of the declining force of natural selection with age. We discuss here the evidence that among the causes of aging in complex multicellular organisms, such as mammals, is the antagonistically pleiotropic effects of the cellular responses that protect the organism from cancer. Cancer is relatively rare in young mammals, owing in large measure to the activity of tumor suppressor mechanisms. These mechanisms either protect the genome from damage and/or mutations, or they elicit cellular responses--apoptosis or senescence--that eliminate or prevent the proliferation of somatic cells at risk for neoplastic transformation.We focus here on the senescence response, reviewing its causes, regulation and effects. In addition, we describe recent data that support the idea that both senescence and apoptosis may indeed be the double-edged swords predicted by the evolutionary hypothesis of antagonistic pleiotropy--protecting ...
2004-08-15
Divided into three sections, this paper briefly presents Kohlberg's theory of moral reasoning; surveys some key research relating childrearing practices to adolescents' social competence, including moral reasoning; and reports research findings concerning the value systems adolescents develop. The first section characterizes preconventional, conventional, and postconventional morality and explores ways of promoting the development of a mature concept of justice, which includes role taking and living in a "just community." The second section focuses on aspects of social learning, which include authoritative parenting, inductive discipline, argumentative discourse, and tradition-based upbringing. In addition, this section explores socialization practices that hinder the development of mature moral reasoning. Focusing initially on characteristics of alienated youth and parental influences on such youth, the third section describes studies investigating the values development of New York ...
1981-12-01
International Nuclear Information System (INIS)
Absolute total cross sections for electron-impact excitation of the 2s"2S#->#2p"2P transition in C"3"+ were measured from 7.35 eV to 8.45 eV using the merged electron-ion-beams energy-loss technique. The results settle the discrepancy between two previous experiments using the crossed-beams fluorescence method, being in very good agreement with the older results [P. O. Taylor, D. Gregory, G. H. Dunn, R. A. Phaneuf, and D. H. Crandall, Phys. Rev. Lett. 39, 1256 (1977)] but less so with the more recent ones [D. W. Savin, L. D. Gardner, D. B. Reisenfeld, A. R. Young, and J. L. Kohl, Phys. Rev. A 51, 2162 (1995)]. The present measurements are also in good agreement with unitarized Coulomb-Born and close-coupling calculations. copyright 1998 The American Physical Society.
ACerS History: Ceramic Education
Website hosted by the American Ceramics Society with history of ceramics education, along with notable ceramic engineering educators. "In May 1894, two rooms in the basement of The Ohio State University?s College of Engineering were set aside to create a new department: Clay-Working and Ceramics. Founded with a $10,000 grant from the State of Ohio, the department was the first of its kind anywhere in the nation. The course of study was the idea and personal project of Edward Orton Jr., a young mining engineer. Orton had gathered his ceramic knowledge, piece by piece, from various jobs in coalmines, glass factories and steel plants. In 1893 he was the superintendent for a factory that made paving bricks. Orton?s factory, hit by an ?acute crisis,? closed, leaving him with some unexpected extra time. He used the opportunity to lobby for the passage of what some people dubbed the ?Mud Pie Bill? ? legislated funding to establish a school to train professionals in the ...
2008-03-01
A radiation hardening model of 9%Cr-martensitic steels including dpa and helium
International Nuclear Information System (INIS)
This paper provides a physically-based engineering model to estimate radiation hardening of 9%Cr-steels under both displacement damage (dpa) and helium. The model is essentially based on the dispersed barrier hardening theory and the dynamic re-solution of helium under displacement cascades but incorporating a number of assumptions and simplifications [Trinkaus, J. Nucl. Mater. 318 (2003) 234-340]. As a result, the kinetics of the damage accumulation kept fixed, its amplitude is fitted on one experimental condition. The model was rationalized on an experimental database that mainly consists of ?9%Cr-steels irradiated in the range of 50-600 deg. C up to 50 dpa and with a He-content up to 5000 appm. The test temperature effect is taken into account through a normalization procedure based on the change of the Young's modulus and the anelastic deformation that occurs at high temperature. Despite the large experimental scatter, inherent to the variety of the material ...
2009-04-30
A MODEL OF THE SPECTRAL EVOLUTION OF PULSAR WIND NEBULAE
International Nuclear Information System (INIS)
We study the spectral evolution of pulsar wind nebulae (PWNe) taking into account the energy injected when they are young. We model the evolution of the magnetic field inside a uniformly expanding PWN. Considering time-dependent injection from the pulsar and coolings by radiative and adiabatic losses, we solve the evolution of the particle distribution function. The model is calibrated by fitting the calculated spectrum to the observations of the Crab Nebula at an age of a thousand years. The spectral evolution of the Crab Nebula in our model shows that the flux ratio of TeV #gamma#-rays to X-rays increases with time, which implies that old PWNe are faint in X-rays, but not in TeV #gamma#-rays. The increase of this ratio is because the magnetic field decreases with time and is not because the X-ray emitting particles are cooled more rapidly than the TeV #gamma#-ray emitting particles. Our spectral evolution model matches the observed rate of the radio flux decrease ...
2010-06-01
A Compact Linac for Proton Therapy Based on a Dielectric Wall Accelerator
Energy Technology Data Exchange (ETDEWEB)
A novel compact CT-guided intensity modulated proton radiotherapy (IMPT) system is described. The system is being designed to deliver fast IMPT so that larger target volumes and motion management can be accomplished. The system will be ideal for large and complex target volumes in young patients. The basis of the design is the dielectric wall accelerator (DWA) system being developed at the Lawrence Livermore National Laboratory (LLNL). The DWA uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. High electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The system will produce individual pulses that can be varied in intensity, energy and spot width. The IMPT planning system will optimize delivery characteristics. The system will be capable of being sited in a conventional linac vault and provide intensity ...
2007-10-29
International Nuclear Information System (INIS)
It has been previously stated that the minimum physiological recommendations for the indispensable amino acids in health adults, as proposed by FAO/WHO/UNU in 1985, are far too low, except for the methionine. An amino acid stable isotopic kinetic study was conducted to seek further experimental support to this hypothesis. Twenty healthy young men received an l-amino acid based diet, supplying 140 mg N.kg"-"1.d"-"1, patterned on egg protein for 1 week, then for 3 weeks either i) a pattern based on current international recommendations (FAO diet, n=7), ii) a the tentative Laboratory of Human Nutrition of the Massachusetts Institute of Technology, new amino acid recommendation pattern (MIT diet, n=7) or iii) again the egg hen pattern (EGG diet, n=6). All subjects were again studied for one final, consecutive week of the egg diet. At the end of the initial week, at the first and third week with the three experimental diets,and after three days following the return of ...
On the impact of low power density microwaves in some living tissues
Energy Technology Data Exchange (ETDEWEB)
The biomedical and ecological interest for the microwave impact on the Earth biosphere is continuously increased since the industrial, military and communication activities strongly contribute to the electromagnetic stress of living bodies. In the next the authors present some of the main results obtained regarding the microwave exposure of various types of biological material: bacteria, fungi, young plant seedlings, dry seeds, animal tissues. The electromagnetic exposure was carried out in open space in well controlled environmental conditions by using 10.75 GHz/1 m W cm{sup -2} microwaves. Biochemical assays and cytogenetic tests have been carried out to reveal the changes induced post irradiation. The response of some pathogen bacteria, have been emphasized by means of turbidimetric measurements - the stimulatory effect being noticed at the level of the microbial population density (the stimulation of the human body microbial flora seems to be one of the side ...
2006-07-01
THE EVOLUTION OF THE STAR FORMATION RATE OF GALAXIES AT 0.0 #<=# z #<=# 1.2
International Nuclear Information System (INIS)
We present the 24 #mu#m rest-frame luminosity function (LF) of star-forming galaxies in the redshift range 0.0 #<=# z #<=# 0.6 constructed from 4047 spectroscopic redshifts from the AGN and Galaxy Evolution Survey of 24 #mu#m selected sources in the Booetes field of the NOAO Deep Wide-Field Survey. This sample provides the best available combination of large area (9 deg"2), depth, and statistically complete spectroscopic observations, allowing us to probe the evolution of the 24 #mu#m LF of galaxies at low and intermediate redshifts while minimizing the effects of cosmic variance. In order to use the observed 24 #mu#m luminosity as a tracer for star formation, active galactic nuclei (AGNs) that could contribute significantly at 24 #mu#m are identified and excluded from our star-forming galaxy sample based on their mid-IR spectral energy distributions or the detection of X-ray emission. Optical emission line diagnostics are considered for AGN identification, ...
2010-08-01
THE DOUBLE-DEGENERATE NUCLEUS OF THE PLANETARY NEBULA TS 01: A CLOSE BINARY EVOLUTION SHOWCASE
International Nuclear Information System (INIS)
We present a detailed investigation of SBS 1150+599A, a close binary star hosted by the planetary nebula PN G135.9+55.9 (TS 01). The nebula, located in the Galactic halo, is the most oxygen-poor known to date and is the only one known to harbor a double degenerate core. We present XMM-Newton observations of this object, which allowed the detection of the previously invisible component of the binary core, whose existence was inferred so far only from radial velocity (RV) and photometric variations. The parameters of the binary system were deduced from a wealth of information via three independent routes using the spectral energy distribution (from the infrared to X-rays), the light and RV curves, and a detailed model atmosphere fitting of the stellar absorption features of the optical/UV component. We find that the cool component must have a mass of 0.54 #+-# 0.2 M_s_u_n, an average effective temperature, T_e_f_f, of 58,000 #+-# 3000 K, a mean radius of 0.43 #+-# ...
2010-05-01
New sets of cross sections for the production of krypton isotopes from targets of Rb, Sr, Y, and Zr were constructed primarily on the bases of experimental excitation functions for Kr production from Y. These cross sections were used to calculate galactic-cosmic-ray and solar-proton production rates for Kr isotopes in the moon. Spallation Kr data obtained from ilmenite separates of rocks 10017 and 10047 are reported. Production rates and isotopic ratios for cosmogenic Kr observed in ten well-documented lunar samples and in ilmenite separates and bulk samples from several lunar rocks with long but unknown irradiation histories were compared with predicted rates and ratios. The agreements were generally quite good. Erosion of rock surfaces affected rates or ratios for only near-surface samples, where solar-proton production is important. There were considerable spreads in predicted-to-observed production rates of /sup 83/Kr, due at least in part to uncertainties in ...
1979-01-01
Pre-Flight Development of the PoGOLite Pathfinder
International Nuclear Information System (INIS)
The Polarized Gamma-ray Observer (PoGOLite) is a balloon-borne instrument that will measure gamma-ray polarization in the energy range 25-80 keV from astronomical sources such as pulsars, accretion discs and jets from active galactic nuclei. The two additional parameters provided by such observations, polarization angle and degree, will allow these objects to be studied in a new way, providing information about their emission mechanisms and geometries. The instrument measures azimuthal scattering angles of photons within a close packed array of phoswich detector cells (PDCs) based on coincident detection of Compton scattering and photoelectric absorption. Each PDC comprises three different scintillating components and combines photon detection, active collimation and bottom anticoincidence into one single unit. The three parts are viewed by a photomultiplier tube (PMT) and pulse shape discrimination is used to identify signals from dierent parts. Surrounding the ...
Launching proton-dominated jets from accreting Kerr black holes: the case of M87
A general relativistic model for the formation and acceleration of lowmass-loaded jets from systems containing accreting black holes is presented. The model is based on previous numerical results and theoretical studies in the Newtonian regime, but modified to include the effects of space-time curvature in the vicinity of the event horizon of a spinning black hole. It is argued that the boundary layer between the Keplerian accretion disk and the event horizon is best suited for the formation and acceleration of the accretion-powered jets in active galactic nuclei and micro-quasars. The model presented here is based on matching the solutions of three different regions: i- a weakly magnetized Keplerian accretion disk in the outer part, where the transport of angular momentum is mediated through the magentorotational instability, ii- a strongly magnetized, advection-dominated and turbulent-free boundary layer (BL) between the outer cold accretion disk and the event ...
2011-07-01
DISSIPATION AND EXTRA LIGHT IN GALACTIC NUCLEI. III. 'CORE' ELLIPTICALS AND 'MISSING' LIGHT
International Nuclear Information System (INIS)
We investigate how 'extra' or 'excess' central light in the surface brightness profiles of cusp or power-law elliptical galaxies relates to the profiles of ellipticals with cores. The envelopes of cusp ellipticals are established by violent relaxation in mergers acting on stars present in gas-rich progenitor disks, while their centers are structured by the relics of dissipational, compact starbursts. Ellipticals with cores are formed by the subsequent merging of the now gas-poor cusp ellipticals, with the fossil starburst components combining to preserve a dense, compact component in these galaxies as well (although mixing of stars smooths the transition from the outer to inner components in the profiles). By comparing extensive hydrodynamical simulations to observed profiles spanning a broad mass range, we show how to observationally isolate and characterize the relic starburst component in core ellipticals. Our method recovers the younger starburst population, demonstrating that ...
2009-04-01
DISSIPATION AND EXTRA LIGHT IN GALACTIC NUCLEI. II. 'CUSP' ELLIPTICALS
International Nuclear Information System (INIS)
We study the origin and properties of 'extra' or 'excess' central light in the surface brightness profiles of cusp or power-law elliptical galaxies. Dissipational mergers give rise to two-component profiles: an outer profile established by violent relaxation acting on stars already present in the progenitor galaxies prior to the final stages of the merger, and an inner stellar population comprising the extra light, formed in a compact central starburst. By combining a large set of hydrodynamical simulations with data that span a broad range of profiles at various masses, we show that observed cusp ellipticals appear consistent with the predicted 'extra light' structure, and we use our simulations to motivate a two-component description of the observations that allows us to examine how the properties and mass of this component scale with, e.g., the mass, gas content, and other properties of the galaxies. We show how to robustly separate the physically meaningful extra light and outer, ...
2009-03-01
Energy Technology Data Exchange (ETDEWEB)
The purpose of this study was to evaluate the ability to enhance distribution of eelgrass (Zostera marina) in the Columbia River Estuary to serve as refuge and feeding habitat for juvenile salmon, Dungeness crab, and other fish and wildlife. We strongly suspected that limited eelgrass seed dispersal has resulted in the present distribution of eelgrass meadows, and that there are other suitable places for eelgrass to survive and form functional meadows. Funded as part of the Bonneville Power Administration's call for Innovative Projects, we initiated a multistage study in 2008 that combined modeling, remote sensing, and field experimentation to: (1) Spatially predict habitat quality for eelgrass; (2) Conduct experimental plantings; and (3) Evaluate restoration potential. Baseline in-situ measurements and remote satellite observations were acquired for locations in the Lower Columbia River Estuary (LCRE) to determine ambient habitat conditions. These were used to create a ...
2009-09-08
Unusual Recharge Processes near Arroyos of the Rio Grande Aquifer, El Paso/Juarez Area
The twin-cities of El Paso and Juarez share the water resources of the Hueco Bolson aquifer and overlying Rio Grande aquifer. Both aquifers span the international border between Mexico and the United States. Salinity in the Rio Grande aquifer varies widely, some parts of the shallow aquifer containing less than 1,000 mg/L total dissolved solids (TDS), other parts of the aquifer exceeding 5,000 mg/L TDS. One sizable part of the "Lower Valley" area, approximately 45 km below El Paso contains very dilute water near the outer edge of the floodplain. Historically it had been thought that the dilute waters in this location were derived from recharge from arroyos that drained proximal parts of the Hueco Bolson. Instead, our hydrogen and oxygen isotope data and carbon-14 data indicate that these dilute waters were derived from pre-dam infiltration of the Rio Grande. Relatively light and slightly evaporated pre-dam waters (-11.5 del O18) at the arroyos are also relatively ...
2005-12-01
Turnover of whole body proteins and myofibrillar proteins in middle-aged active men
International Nuclear Information System (INIS)
Endurance-trained older men have a higher proportion of lean tissue and greater muscle cell oxidative capacity, reversing age-related trends and suggesting major changes in protein metabolism. In this study, protein turnover was determined in 6 middle-aged (52+/-1 yr) men who were well trained (VO_2 max 55.2+/-5.0 ml O_2/kg.min) and lean (body fat 18.9+/-2.8%, muscle mass 36.6+/-0.6%). The maintained habitual exercise while consuming 0.6, 0.9 or 1.2 g protein/kg.day for 10-day periods. N flux was measured from "1"5N in urea after oral "1"5N-glycine administration. Myofibrillar protein breakdown was estimated from urinary 3-methyl-histidine. Dietary protein had no effect on turnover rates, even when N balance was negative. Whole body protein synthesis was 3.60+/-0.12 g/kg.day and breakdown was 3.40+/-0.14 g/kg.day for all N intakes. Whole body protein flux, synthesis and breakdown were similar to values reported for sedentary young (SY) or sedentary old (SO) men on ...
1986-04-13
International Nuclear Information System (INIS)
We have measured the densities at temperatures T = (278.15 to 363.15) K and heat capacities at T = (278.15 to 393.15) K of aqueous solutions of 18-crown-6 and of (18-crown-6 + KCl) at molalities m = (0.02 to 0.3) mol . kg"-"1 and at the pressure 0.35 MPa. We have calculated apparent molar volumes V_#phi# and apparent molar heat capacities C_p_,_#phi# for 18-crown-6(aq), and we have applied Young's Rule and have accounted for chemical speciation and relaxation effects to resolve V_#phi# and C_p_,_#phi# for the (18-crown-6: K"+,Cl"-)(aq) complex in the mixture. We have also calculated estimates of the change in volume #DELTA#_rV_m, the change in heat capacity #DELTA#_rC_p_,_m, the change in enthalpy #DELTA#_rH_m, and the equilibrium quotient log Q for formation of the complex at T = (278.15 to 393.15) K and m = (0 to 0.3) mol . kg"-"1.
2004-12-01
International Nuclear Information System (INIS)
Full text: Founded in 1964, Ankara Nuclear Research and Training Center (ANRTC) conducts and facilitates the scientific activities including training (summer practice, MSc and Ph D studies in physics and chemistry, IAEA fellowship programs etc.), research and other studies in nuclear and related fields. As it's a part of main duties, ANRTC has analysis on the variety of samples, and radiation protection services commercially, for radiation workers in state, public and private sectors. Research, development and application projects implemented in this Center have mostly been supported by State Planning Organization (SPO) and Turkish Atomic Energy Authority (TAEA). In addition to the projects there are on going collaborative studies with some national Universities and International Atomic Energy Agency. The main activities carried out in ANRTC can be summarized as: studies on experimental nuclear physics, application of nuclear techniques such as XRF, XRD, Gamma, Alpha, etc. for ...
2004-10-01
The characteristics of a hydroxyapatite-chitosan-PMMA bone cement.
In this study, we propose a new bioactive bone cement (BBC), composed of natural bone powder (hydroxyapatite; HA), chitosan powder, and the currently available polymethylmethacrylate (PMMA) bone cement, for use in orthopedic surgeries such as vertebroplasty or as bone filler. Three types of BBCs (BBC I, BBC II, and BBC III) were prepared with different composition ratios. In vitro tests and animal studies were performed with the new BBCs, and with a currently available commercial PMMA bone cement. Surface morphology, chemical composition, changes in pH over time, exothermic temperatures, intrusion, and cellular responses were investigated in vitro. Scanning electron microscopy (SEM) and radiological and histological examinations were performed in animal studies. The results showed that the major components of the BBCs were C, O, Ca, P, Cl, Si, S, Ba, and Mg. The pH values of the BBCs decreased after 1 day, but eventually recovered to 7.2-7.4. The water absorbency, weight loss, and ...
2004-11-01
Stochastic risk estimation from medical x-ray diagnostic examinations, 2
International Nuclear Information System (INIS)
The risks of genetic, leukemia and malignant diseases from medical X-ray diagnostic examinations were estimated using the frequency of radiographic and fluoroscopic exposures per diagnostic examination, child expectancy, leukemia and malignancy significant factors, and using a weighting factor determined on the basis of data concerning the cancer mortality among atomic bomb survivors in Nagasaki and of a recommendation of International Commission of Radiological Protection. The organ or tissue doses with respect to the stochastic risks were determined with ionization chambers and thermoluminescent dosimeters placed at the positions of the organs or tissues in a RANDO woman phantom which was exposed to diagnostic X-rays according to technical factors of typical radiographic and fluoroscopic examinations obtained from a nationwide survey. The resultant risks by age-group and type of radiographic and fluoroscopic examination are tabulated in terms of risk level of 10"-"6. In general, the ...
1981-01-01
Silica, silicosis and tuberculosis.
Exposure to crystalline silica dust causes multiple diseases, but silicosis and silica dust-associated tuberculosis (TB), in particular, are the two diseases that remain high on the list of occupational health priorities in low-income countries and that still occur in some high-income countries. The prevalence of silica-related TB is exacerbated by the human immunodeficiency virus (HIV) epidemic in low-income countries. This review describes the morphology of silica and the variable potency of the different forms. Sources of crystalline silica are discussed, with emphasis on less commonly recognised sources, such as small-scale mining operations and agriculture. Trends in the prevalence of silicosis are also presented. Although efforts have been made for many years in most countries to reduce silica dust levels, silicosis continues to occur even in young people. The clinical and pathological features and diagnosis of silicosis, with emphasis on chest radiography, ...
2007-05-01
Radiation effects on shoot tip culture of chrysanthemum, 2
International Nuclear Information System (INIS)
(1) Young chrysanthemums were planted after being irradiated at the time of shoot tip culture and the influence of irradiation was evaluated from the point of view of establishment of mutants. (2) Two cultivars, Kin-tenryu and Tenryu-no-asa were used in this experiment. The percentage of cultivars healthy enough to transplant on June 10, 1972 showed a decrease in proportion to the increase of dosage. Some plants of cultivar Kin-tenryu died after being transplanted. (3) Few plants of either cultivar could overwinter, and in particular no plant irradiated by gamma-rays of 20 kR. (4) Plant height showed a tendency of inhibition in both cultivars. (5) Three chlorophyll mutants showing chimera appeared. One of them was in the cultivar Tenryu-no-asa irradiated by 10 kR at 3 days after planting; two of them were in the cultivar Tenryu-no-asa irradiated by 10 kR at 5 days after planting. One mutant exhibiting malformation of entire leaves appeared in the cultivar ...
Quaternary tilt of Death Valley determined from landform modelling of alluvial fans
Energy Technology Data Exchange (ETDEWEB)
Alluvial fans along the east side of central Death Valley are being actively back-tilted along the Death Valley fault zone. Initial modelling of the Copper Canyon and Furnace Creek fans led to recognition of distinct segments. Field reconnaissance and aerial photo mapping were conducted to check model results and improve segment discrimination. Surface roughness, relative position, vegetation distribution, and drainage patterns provided independent evidence for segment discrimination. Subsequent modelling of individual segments produced a range of tilt values from 0.275[degree] to 0.559[degree] down to the northeast. Continued analysis of these fan segments is concentrated on: (1) assigning confidence and error values to the tilt values; and (2) dating individual segments. Further work will compare the tilt rates of east-side fans with those from the west. The mean squared error (MSE) is currently being used as a first order assessment of the quality of the model's fit to data ...
1993-04-01
QCD Phase Transitions, Volume 15
Energy Technology Data Exchange (ETDEWEB)
The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of ...
1999-03-20
QCD PHASE TRANSITIONS-VOLUME 15.
Energy Technology Data Exchange (ETDEWEB)
The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of ...
1998-11-04
We present deep images of dust continuum emission at 450, 800, and 850 micron of the dark cloud LDN 1689N which harbors the low-mass young stellar objects (YSOs) IRAS 16293-2422A and B (I16293A and I16293B) and the cold prestellar object I16293E. Toward the positions of I16293A and E we also obtained spectra of CO-isotopomers and deep submillimeter observations of chemically related molecules with high critical densities. To I16293A we report the detection of the HDO 1_01 - 0_00 and H2O 1_10 - 1_01 ground-state transitions as broad self-reversed emission profiles with narrow absorption, and a tentative detection of H2D+ 1_10 - 1_11. To I16293E we detect weak emission of subthermally excited HDO 1_01 - 0_00. Based on this set of submillimeter continuum and line data we model the envelopes around I16293A and E. The density and velocity structure of I16293A is fit by an inside-out collapse model, yielding a sound speed of a=0.7 km/s, an age of t=(0.6--2.5)e4 yr, and a ...
2004-01-01
Primary spinal epidural extraosseous Ewing's sarcoma: Report of five cases and literature review
International Nuclear Information System (INIS)
Ewing's sarcoma is the most common malignant bone tumour occurring in children and adolescents and exists in two different clinico pathological entities: osseous Ewing's sarcoma (OES) and extraosseous Ewing's sarcoma (EES). Five cases of primary epidural EES are described, which presented with non-specific symptoms leading to a long diagnostic delay. The median age at diagnosis was 22 years (range 13-36 years). The median diagnostic delay was 3 months. All patients had one or more neurological deficits. All underwent surgical exploration with a laminectomy and partial resection followed by adjuvant radiotherapy to a dose of 46-50 Gy and chemotherapy with VAC (vincristine, adriamycin and cyclophosphamide) alternating with ICE (ifosphamide, cisplatin and etoposide) for at least six cycles. The mean follow-up period is 21.2 months (range 11-32 months). Four of the five patients achieved a complete remission and are disease free at the time of writing this report. Two patients have a ...
2001-08-01
Energy Technology Data Exchange (ETDEWEB)
The research carried out in Canada in the design of containers for the disposal of radioactive waste has focussed on spent nuclear fuel, even though the quantities of other currently stored radioactive wastes are substantially greater. Research carried out at the Royal Military College of Canada on the effects of mixed fields of radiation on high polymer adhesives and composite materials has shown that some polymers are quite resistant to radiation and could well serve in the fabrication of radioactive waste disposal containers. The purpose of this research was to determine if thermoplastic polymers could be used as superior materials to replace metals in the application of low and intermediate level radioactive waste disposal containers. Polymers have the advantage that they do not corrode like metals. The experimental methods, used in this research, focused on the effects of radiation on the properties of the materials. Polypropylene, Nylon 66, Polycarbonate, and Polyurethane, with ...
2001-07-01
Patterns of radionuclide concentrations in life-cycle of birds
Energy Technology Data Exchange (ETDEWEB)
Breeding populations of Great Tit Parus major and Pied Flycatcher Ficedida hypoleuca was studied to determine radionuclide ({sup 137}Cs, {sup 90}Sr) concentrations in bodies and foods (contents of gastrointestinal tracts) at different stages of the life-cycle and radiation effects upon the populations. The study was carried out in 1989--1992 near Chernobyl (in two areas with differed contamination levels: 90 Ci/km{sup 2}, 5 Ci/km{sup 2}) and East-Ural radioactive trace (Russia) (1,500 Ci/km{sup 2}, 2 Ci/km{sup 2}). Concentrations of {sup 90}Sr in egg shells of Great Tit collected near Chernobyl were 65 times higher in the more radioactive area than in the less contaminated area and varied from 56.6 to 79.7 Bq/g. Concentration of {sup 90}Sr in the contents of gastrointestinal tracts were from 0 to 10.8 Bq/g. Concentrations of radionuclides in the food increased in the sequence ``nestlings < fledglings < adults``. However, the accumulation declined from nestlings to adults. {sup ...
1995-12-31
Energy Technology Data Exchange (ETDEWEB)
The aim of the thesis is to validate concepts used in hydrocarbon generation and migration models; the model considered is the Temispack model developed by IFP, and the validation is based on the investigation of the thermal and hydraulic evolution in various sedimentary basins. It is shown that, in general, the thermal history of sediments is influenced by external processes (sedimentation rates, lithology, climate changes, regional-scale groundwater circulations) which frequently overprint internal processes (variations of crustal/mantle heat flow). It is found that external processes can frequently explain past thermal events that were erroneously attributed to internal causes (tectonic-thermal events). The origin of over-pressures in young basins with high sedimentation rates is shown to be generally related to compaction disequilibrium. Shale permeability values calibrated against overpressure profiles are consistent with experimental constraints. Compaction ...
1997-07-10
We model nongraphitized carbon black surfaces and investigate adsorption of argon on these surfaces by using the grand canonical Monte Carlo simulation. In this model, the nongraphitized surface is modeled as a stack of graphene layers with some carbon atoms of the top graphene layer being randomly removed. The percentage of the surface carbon atoms being removed and the effective size of the defect (created by the removal) are the key parameters to characterize the nongraphitized surface. The patterns of adsorption isotherm and isosteric heat are particularly studied, as a function of these surface parameters as well as pressure and temperature. It is shown that the adsorption isotherm shows a steplike behavior on a perfect graphite surface and becomes smoother on nongraphitized surfaces. Regarding the isosteric heat versus loading, we observe for the case of graphitized thermal carbon black the increase of heat in the submonolayer coverage and then a sharp decline in the heat when ...
2006-09-01
Methionine kinetics in adult men: effects of dietary betaine on L-[2H3-methyl-1-13C]methionine
International Nuclear Information System (INIS)
The effects of a daily 3-g supplement of betaine on kinetic aspects of L-[2H3-methyl-1-13C]methionine (MET) metabolism in healthy young adult men were explored. Four groups of four subjects each were given a control diet, based on an L-amino acid mixture supplying 29.5 and 21.9 mg.kg-1.d-1 of L-methionine and L-cystine for 4 d before the tracer study, conducted on day 5 during the fed state. Two groups received the control diet and two groups received the betaine supplement. Tracer was given intravenously (iv) or orally. The transmethylation rate of MET (TM), homocysteine remethylation (RM), and oxidation of methionine were estimated from plasma methionine labeling and 13C enrichment of expired air. RM tended to increase (P = 0.14) but the TM and methionine oxidation were significantly (P less than 0.05) higher after betaine supplementation when estimated with the oral tracer. No differences were detected with the intravenous tracer. Methionine concentration in ...
Luminous HC3N line emission in NGC4418 - buried AGN or nascent starburst?
IRAM 30m observations reveal that the deeply obscured IR-luminous galaxy NGC4418 has a rich molecular chemistry - including unusually luminous HC3N line emission. We furthermore detect: ortho-H2CO 2-1, 3-2; CN 1-0, 2-1; HCO+, 1-0. 3-2, HCN 3-2, HNC 1-0, 3-2 (and tentatively OCS 12-11). The HCN, HCO+, H2CO and CN line emission can be fitted to densities of n=5 x 10E4 - 10E5 cm-3 and gas temperatures Tk=80-150 K. Both HNC and HC3N are, however, significantly more excited than the other species which requires higher gas densities - or radiative excitation through e.g. mid-IR pumping. The HCN line intensity is fainter than that of HCO+ and HNC for the 3-2 transition, in contrast to previous findings for the 1-0 lines where the HCN emission is the most luminous. We tentatively suggest that the observed molecular line emission is consistent with a young starburst, where the emission can be understood as emerging from dense, warm gas with an additional PDR component. We ...
2007-01-01
International Nuclear Information System (INIS)
Purpose: To identify results and prognostic factors on long-term survival and local control following treatment of localized Ewing's sarcoma. Patients and Methods: Between 1979 and 2004, a total of 60 children and young adults with Ewing's sarcoma were treated. Patients with distant metastases at presentation (n = 6) and recurrent cases (n = 2) were excluded from this analysis. Patients were exclusively treated within ongoing national and international protocols CESS-81, CESS-86, EICESS-92, EURO-EWING-99. All patients received local irradiation with a total dose of 45-60 Gy; in addition, 41 (79%) of the patients had local surgical procedures, 27 (52%) of them with clear margins. Results: Overall survival rates at 5 and 10 years were 56% and 45%, respectively. Patients #<=# 14 years at diagnosis had overall survival rates of 66% and 61% at 5 and 10 years compared to older patients with corresponding survival rates of 47% and 31%, respectively (p = 0.05). Patients ...
2008-03-01
The Kansas State Board of Education awarded $10.25 million to local education agencies through the Carl D. Perkins Vocational and Applied Technology Education Act of 1990. A work group developed the System of Measures and Standards of Performance (SMSP). Programs for single parents, displaced homemakers, and single pregnant women were funded to provide education/training, employment readiness, and job placement. Seven gender equity facilitator projects and 17 projects to provide young women access to training and support services for technical and nontraditional occupations were funded. Funding provided programs for criminal offenders in corrections institutions and special populations students. To promote state leadership and professional development, funds for curriculum development, inservice training, and vocational student organizations were awarded. Community-based organizations provided transitional programs, outreach programs, and other services for ...
1994-01-11
International Symposium on Nuclear Energy SIEN 2009. Nuclear Power - A New Challenge
International Nuclear Information System (INIS)
The SIEN 2009 symposium organized by Romanian Nuclear Energy Association, AREN, in co-operation with Romanian Atomic Forum, ROMATOM, was primarily targeting the expert community involved in developing new nuclear power projects and implementing the National Nuclear Program. The symposium was also open as a discussion and information forum for scientists, engineers, technicians and students interested in scientific and technologic topics of Nuclear Power. It was structured in the following 6 sections: - Nuclear new builds and developments; - Operation, inspection and maintenance; - Increasing nuclear safety features; - Fuel cycle and decommissioning; - Public perception and confidence strengthening; - Environmental management. The symposium began with three plenary lectures dealing with: - Sustainable Nuclear Energy European Technology Platform; - Nuclear new-build; - Current issues of nuclear equipment standardization in Romania. A poster session of 5 presentations and a workshop ...
2009-10-12
Parenting programmes are effective interventions for preventing and treating conduct problems in young children. Up to 20% of children in disadvantaged areas have conduct disorder. Recent government initiatives such as targeting early years services to designated disadvantaged Flying Start areas in Wales have resulted in increased nursery-care provision for pre-schoolers, yet little has been done to equip nursery staff with effective child behaviour management strategies. The purpose of this non-randomised trial platform study was to establish the feasibility of delivery and the effectiveness of the new Incredible Years Toddler Parent Programme in supporting nursery staff in managing difficult behaviour in the nursery. The Parent Programme is a 12-session (a two-hour session/week) course for carers/parents of children aged one to three years old, which encourages carers to: establish positive relationships with children through play and child-centred activities; ...
2010-12-01
Health impact of low indoor temperatures
Energy Technology Data Exchange (ETDEWEB)
The undeniable success in controlling some preventable communicable respiratory diseases in Europe has created an impression that respiratory infections are no longer as dangerous as they once were, and efforts of public health services should be concentrated on other problems. However, epidemiological data do not exactly confirm this optimistic view, as acute respiratory diseases are among the leading causes of death in Europe. When morbidity statistics - which are usually less reliable - are considered, acute respiratory infections in Europe take the lead among all communicable diseases. For example, each year 15% of the population in Spain and 30% of the population in the United Kingdom have a recorded acute respiratory disease. Several environmental risk factors of acute respiratory diseases have been recorded, the main ones being indoor and outdoor air pollution, overcrowding in dwellings and public transport, and poor indoor climate. Improvement of the indoor climate of dwellings ...
1987-01-01
International Nuclear Information System (INIS)
Japan International Cooperation Agency (JICA) Technical Cooperation Project on Reduction of Seismic Risk for Buildings and Structures started in Romania on October 1, 2002. The aim of the Project is to strengthen the capacity of earthquake disaster related activities in Romania. The Project approval is the result of four years of intensive efforts made by professionals from Technical University of Civil Engineering Bucharest (UTCB), Ministry of Transport, Constructions and Tourism (MTCT), Romania, National Building Research Institute (INCERC) Bucharest, JICA, Building Research Institute (BRI), Tsukuba, and National Institute for Land, Infrastructure and Management (NILIM), Tsukuba, Japan. The duration of the Project is five years. The implementing agency is the National Center for Seismic Risk Reduction (NCSRR) as a public institution of national interest under MTCT. The activities are carried out by NCSRR in partnership with UTCB and INCERC. During the Project period, 29 ...
2007-04-26
International Nuclear Information System (INIS)
The fundamentals and the technical application methods of the imaging procedures are discussed in detail with regard to their application in medicine. The development of the X-ray contrast media has led to a better tolerance and a significant reduction of risks. Problems relating to radiation protection and radiation exposure are discussed critically. The general point gives an overview of the radiological examination methods and is meant to deepen the understanding of the special techniques and their rationally determined application. The following special part deals with diagnosing of organs in the region of the neck and the thorax. The general basis is the conventional radiological examination. The great increase in information achieved by means of the new imaging methods becomes clear if we look at the diagnostics of the soft tissue of the neck. Computerized tomography and NMR imaging open the view at the fine structures of the mediastinum. Mammography is an examination method ...
We will present the first astronomical images taken with MIRSI (Mid-InfraRed Spectrometer and Imager). First light for MIRSI is scheduled for December 2001. MIRSI is a mid-infrared camera system recently completed at Boston University that has both spectroscopic and imaging capabilities. The camera utilizes a new 320x240 Si:As IBC array developed for ground-based astronomy by Raytheon/SBRC. MIRSI offers a large field of view (1.6 arcmin x 1.2 arcmin at the IRTF with a pixel scale of 0.3 arcsec), diffraction-limited spatial resolution, complete spectral coverage over the 8-14 micron and 17-26 micron atmospheric windows for both imaging (discrete filters and CVF) and spectroscopy (10 and 20 micron grisms), and high sensitivity (expected 1-sigma point source sensitivities of 5 and 20 mJy at 10 and 20 microns, respectively, for on-source integration time of 30 seconds). This system offers the unique ability to acquire both spectra and high-resolution, multi-wavelength images of an ...
2001-12-01
International Nuclear Information System (INIS)
The formation and evolution of the circumstellar disk in unmagnetized molecular clouds is investigated using three-dimensional hydrodynamic simulations from the prestellar core until the end of the main accretion phase. In collapsing cloud cores, the first (adiabatic) core with a size of #approx#>3 AU forms prior to the formation of the protostar. At its formation, the first core has a thick disk-like structure and is mainly supported by the thermal pressure. After the protostar formation, it decreases the thickness gradually and becomes supported by the centrifugal force. We found that the first core is a precursor of the circumstellar disk with a size of >3 AU. This means that unmagnetized protoplanetary disk smaller than <3 AU does not exist. Reflecting the thermodynamics of the collapsing gas, at the protostar formation epoch, the first core (or the circumstellar disk) has a mass of #approx#0.005-0.1 M_s_u_n, while the protostar has a mass of #approx#10"-"3 M_s_u_n. Thus, ...
2010-12-01
Evolution of nitrogen oxide(s) during in vivo nitrate reductase assay of soybean leaves
Energy Technology Data Exchange (ETDEWEB)
Studies were conducted to quantitate the evolution of nitrogen oxides (NO/sub (x)/) from soybean (Glycine max (L.) Merr.) leaves during in vivo nitrate reductase (NR) assays with aerobic and anaerobic gas purging. Anaerobic gas purging (N/sub 2/ and argon) consistently resulted in greater NO/sub (x)/ evolution than did aerobic gas purging (air and O/sub 2/). The evolution of NO/sub (x)/ was dependent on gas flow rate and on NO/sub 2//sup -/ formation in the assay medium; although a threshold level of NO/sub 2//sup -/ appeared to exist beyond which the rate of NO/sub (x)/ evolution did not increase further. The loss of NO/sub (x)/ from in vivo NR assays under gas purging explains partially, but not stoichiometrically, the decrease of NO/sub 2//sup -/ accumulation in in vivo NR assay medium with young soybean leaves. The lack of stoichiometry between NO/sub (x)/ evolution and apparent NO/sub 2//sup -/ loss suggests that other mechanisms are also involved in loss of ...
1981-12-01
Based on a recent investigation that modeled the elastic properties (ie, strength, stiffness and range) of multistranded wires made from linearly elastic materials, three-stranded (triple) and six-stranded coaxial (coax) stainless steel (SS) wires were compared to single-stranded (single) SS and conventional nickel titanium (NiTi) leveling wires. To measure Young's modulus of elasticity (E), flexural tests were performed with an Instron mechanical testing machine in a three-point bending arrangement having a span length of 8.9 mm or 12.5 mm. A strong correlation between wire stiffness and the area moment of inertia demonstrated that strand interaction was negligible at low activations and that E = 199 GPa was constant even for the heavily drawn coax strands. Using the Instron with an extensometer, the 0.1% yield strengths (sigma(YS)) of the single SS wires and the straight inner strands within the coax wires were tested. The ratio of the sigma(YS) to the ultimate ...
2002-08-01
International Nuclear Information System (INIS)
Mutations in transcription factors hepatocyte nuclear factors (HNF)-1#alpha# and HNF-1#beta# cause maturity-onset diabetes of the young (MODY) types 3 and 5, respectively. HNF-1#alpha# and HNF-1#beta# mutations are well studied in some tissues, but the mechanism by which HNF-1#alpha# and HNF-1#beta# mutations affect sucrase-isomaltase (SI) transcription in the small intestine is unclear. We studied the effects of 13 HNF-1#alpha# mutants and 2 HNF-1#beta# mutants on human SI gene transcription, which were identified in subjects with MODY3 and MODY5, respectively. Transactivation activity of 11 HNF-1#alpha# and 2 HNF-1#beta# mutants was significantly lower than that of wild (wt)-HNF-1#alpha# and wt-HNF-1#beta#. Furthermore, in co-expression studies with mutant (mu)-HNF-1#alpha#/ wt-HNF-1#beta# and wt-HNF-1#alpha#/mu-HNF-1#beta#, the combination of mu-HNF-1#alpha# (P379fsdelCT and T539fsdelC)/wt-HNF-1#beta# impaired SI transcription, but the others were not remarkably ...
2004-12-03
International Nuclear Information System (INIS)
We present sensitive high angular resolution (0.''57-0.''78) SO, SO_2, CO, C_2H_5OH, HC_3N, and HCOCH_2OH line observations at millimeter and submillimeter wavelengths of the young O-type protostar W51 North made with the Submillimeter Array. We report the presence of a large (about 8000 AU) and hot molecular circumstellar disk around this object, which connects the inner dusty disk with the molecular ring or toroid reported recently and confirms the existence of a single bipolar outflow emanating from this object. The molecular emission from the large disk is observed in layers with the transitions characterized by high excitation temperatures in their lower energy states (up to 1512 K) being concentrated closer to the central massive protostar. The molecular emission from those transitions with low or moderate excitation temperatures is found in the outermost parts of the disk and exhibits an inner cavity with an angular size of around 0.''7. We modeled all lines ...
2010-12-10
Energy Technology Data Exchange (ETDEWEB)
Objective: To assess dynamic MRI with Gd-DTPA enhancement for evaluating inflammatory changes in the subacromial bursa. Design and patients: We detected the signal intensity changes in dynamic MRI of the subacromial bursa, and confirmed these macroscopically by arthroscopy and histologically. The signal intensity was measured using built-in software, and the enhancement ratio (E ratio) was calculated from dynamic MR images. In addition, as a parameter of the rate of the increase in the signal intensity from 0 to 80 s, the mean increase per second in the E ratio was obtained as the coefficient of enhancement (CE). The correlation was studied of the E ratio and CE with the arthroscopic findings (redness, villous formation, thickening and adhesion), and of the E ratio and CE with the histological findings (capillary proliferation, papillary hyperplasia, fibrosis and inflammatory cell infiltration) of the subacromial bursa. Of patients with shoulder pain, this study included those with ...
2003-09-01
Energy Technology Data Exchange (ETDEWEB)
A large part of mechanical and durability characteristics of cement-based materials comes from the performances of the hydrated cement, cohesive matrix surrounding the granular skeleton. Experimental studies, in situ or in laboratory, associated to models, have notably enhanced knowledge on the cement material and led to adapted formulations to specific applications or particularly aggressive environments. Nevertheless, these models, developed for precise cases, do not permit to specifically conclude for other experimental conclusions. To extend its applicability domain, we propose a new evolutive approach, based on reactive transport expressed at the microstructure scale of the cement. In a general point of view, the evolution of the solid compounds of the cement matrix, by dissolutions or precipitations, during chemical aggressions can be related to the pore solution evolution, and this one relied to the ionic exchanges with the external environment. By the utilization of a ...
2004-09-15
Energy Technology Data Exchange (ETDEWEB)
Milk can be a significant source of lead (Pb) for young mammals, including humans. Certain essential trace elements have previously been shown to be specifically associated with particular milk components and such associations often increase bioavailability. Thus, the first goal of this study was to determine the distribution of Pb in cream, casein, and whey fractions of various milks under various conditions using /sup 203/Pb as a tracer. In rat milk almost 90% of the Pb was found to be associated with the casein micelles, regardless of: 1) whether the milk was labeled in vivo or in vitro; b) whether the milk was fresh or frozen; and c) the added concentration of Pb. The remainder of the Pb was approximately equally distributed between cream and whey. A virtually identical pattern of Pb distribution was observed with bovine milk. Pb added to infant formula also associated predominantly with casein micelles, although the Pb content of this fraction was ...
1988-01-01
Energy Technology Data Exchange (ETDEWEB)
Either airway cooling or sulfur dioxide (SO/sub 2/) can induce bronchoconstriction in many asthmatics. Whether these two stresses act synergistically is a question with important public health implications. Eight young adult asthmatic volunteers were exposed to SO/sub 2/ at 0.0, 0.2, 0.4, and 0.6 ppm, during 5 min heavy exercise at 5 degrees C, both with high (approximately 85%) and with low (approximately 50%) relative humidity. Physiologic response increased with increasing SO/sub 2/ concentration but did not vary significantly with humidity. Symptom response was marginally greater at low than at high humidity. Twenty-four asthmatics were exposed similarly to clean air and to 0.6 ppm SO/sub 2/, at 5 degrees C and also at 22 degrees C, always at high relative humidity. For this group, physiologic and clinical responses to SO/sub 2/ (in excess of responses to clean air) were highly significant, regardless of temperature. The mean excess responses at 5 degrees ...
1984-02-01
Energy Technology Data Exchange (ETDEWEB)
The existence of stem cells committed to the T lymphoid lineage was deduced from studying how rat T and B stem cells differ in their expression of membrane W3/13 antigen and in their susceptibility in vivo to gamma irradiation. Stem cell activity of rat bone marrow and fetal liver was measured in long-term radiation chimeras using B and T cell alloantigenic surface markers to identify the progeny of donor cells. Monoclonal mouse anti-rat thymocyte antibody W3/13 labeled approximately 40% of fetal liver cells and 60-70% of young rat bone marrow cells (40% brightly, 25% dimly). Bright, dim, and negative cells were separated on a fluorescence-activated cell sorter. All B and T lymphoid stem cells in fetal liver were W3/13 bright, as were B lymphoid stem cells in bone marrow. W3/13 dim bone marrow had over half the T cell repopulating activity of unseparated marrow but gave virtually no B cell repopulation. In further experiments, the radiosensitivity of endogenous B ...
1981-01-01
Chronic treatment with polychlorinated biphenyls (PCB) during pregnancy and lactation in the rat
International Nuclear Information System (INIS)
The gender-specific expression pattern of aromatase and 5alpha-reductases (5alpha-R) during brain development provides neurons the right amount of estradiol and DHT to induce a dimorphic organization of the structure. Polychlorinated biphenyls (PCBs) are endocrine disruptive pollutants; exposure to PCBs through placental transfer and breast-feeding may adversely affect the organizational action of sex steroid, resulting in long-term alteration of reproductive neuroendocrinology. The study was aimed at: a) evaluating the hypothalamic expression of aromatase, 5alpha-R1 and 5alpha-R2 in fetuses (GD20), infant (PN12), weaning (PN21) and young adult (PN60) male and female rats exposed to PCBs during development; b) correlating these parameters with the time of testicular descent, puberty onset, estrous cyclicity and copulatory behavior; c) evaluating possible alterations of some non reproductive behaviors (locomotion, learning and memory, depression/anxiety behavior). A ...
2009-08-15
Energy Technology Data Exchange (ETDEWEB)
There was a total bus strike in the Danish town of Esbjerg during the spring of 1995. It lasted for a very long period of time and was extremely disruptive. After this the number of bus passengers fell dramatically. As a result, a group of researchers in this field, employed at Aalborg University initiated an investigation of how former bus passengers solved their personal transport problems without the help of a bus service. Telephone interviews were carried out and 1485 persons agreed to take part in the investigation. The data collected in this way are presented in the paper and give information on the number of people who owned cars, how often members of a family availed themselves of bus transport, age groups, the alternative means of transport used generally or for conveyance to the place of work or school, amount of extra, or less, travel time, travel expenses, and other irritations experienced in connection with the strike. It is concluded that the inhabitants of Esbjerg could ...
1995-12-31
Avian utilization of subsidence wetlands
Energy Technology Data Exchange (ETDEWEB)
Diverse and productive wetlands have resulted from coal mining in the midwest. The trend from surface to underground mining has increased the potential for subsidence. Planned subsidence of longwall mining areas provides increased opportunities for wetland habitat establishment. Planned subsidence over a 180 meter (590 foot) deep longwall mine in southern Illinois during 1984 to 1986 produced three subsidence wetlands totaling 15 hectares (38 acres). The resulting palustrine emergent wetlands enhanced habitat diversity within the surrounding palustrine forested unsubsided area. Habitat assessments and evaluations of avian utilization of the subsidence wetlands were conducted during February 1990 through October 1991. Avian utilization was greatest within the subsided wetlands. Fifty-three bird species representing seven foraging guilds utilized the subsidence wetlands. Wading/fishing, dabbling waterfowl, and insectivorous avian guilds dominated the subsidence wetlands. The subsidence ...
1995-09-01
Assimilation of /sup 14/CO/sub 2/ and /sup 14/C sucrose by citrus fruit tissues
Energy Technology Data Exchange (ETDEWEB)
Assimilation and metabolism of /sup 14/CO/sub 2/ was compared to that of (U-/sup 14/C) sucrose in young grapefruit (ca 25 mm diameter) to determine their respective roles in fruit growth. Fixation of /sup 14/CO/sub 2/ by isolated fruit tissues during 10 min in light exceeded that in dark by 2- to 30-fold depending on tissue content of chlorophyll. Greatest apparent photosynthesis occurred in outer green peel, but green juice tissues assimilated more than did adjoining inner peel tissue. In the dark, juice tissues incorporated 2.5-fold more /sup 14/CO/sub 2/ than any other tissue. Neutral sugars accounted for a smaller proportion and organic acids, a greater proportion, of the /sup 14/C-assimilates in interior peel and juice tissues. These data suggest more extensive production of organic acids from /sup 14/CO/sub 2/ in tissues isolated from the fruit interior. In contrast, little difference among tissues was evident in extent of organic- and amino-acid production ...
1987-04-01
One of the biggest fears and challenges a parent of a child with special needs faces is navigating the post-22 landscape. When a child hits the age of 22, the Department of Elementary and Secondary Education (DESE) is no longer required to provide daily services and support. Whatever the abilities, or disabilities, of a child, every parent has the same concerns about how their child will productively fill their days and live as independently as possible without the safety net of the DESE. One of the transition paths most frequented is entering the workforce. Public and private schools alike work to teach their students the basic skills they need to work. In fact, the national Individuals with Disabilities Education Act (IDEA) states that students must have a transition plan in formulation by the age of 16. This article describes the vocational program developed by the League School of Greater Boston which specifically addresses the challenges students, their parents, and their ...
2010-10-01
A radiation hardening model of 9Cr-martensitic steels including Dpa and helium
International Nuclear Information System (INIS)
Full text of publication follows: Low activation ferritic/martensitic steels are receiving a high priority in the European long term materials research. Although extensively investigated, the available experimental data do not cover all required parameter ranges and cannot unambiguously be used to produce hardening/embrittlement trend curves. Therefore, the main objective of this work is to provide a physically-based engineering model offering a rational to experimental observations. From the literature, experimental data were selected to establish a database that mainly consists of 8 to 9Cr-steels irradiated in the range of 50 to 600 deg. C up to 30 dpa and with a He-content up to 5000 appm. The database includes neutron and proton irradiations, He-implanted as well as B- and Ni-doped steels. Because of the difficulty of interpretation inherent to the Charpy impact test, only tensile data were considered. The difficulty stems from the large range of specimen sizes that are used, the ...
2007-12-10
17- and 24-GHz observations of southern pulsars
We present observations of PSRs J0437-4715, J0738-4042, J0835-4510, J0908-4913, J1048-5832, J1622-4950, J1644-4559, J1721-3532 and J1740-3015 at 17 GHz using the Parkes radio telescope. All nine were detected at 17 GHz, additionally, we detected PSR J0835-4510 and J1622-4950 at 24 GHz. Polarization profiles of each pulsar and the variation with frequency are discussed. In general, we find that the highly polarized edge components of young pulsars continue to dominate their profiles at 17 GHz. Older pulsars (?105 yr) appear to be almost completely depolarized. Our detection of PSR J0437-4715 is the highest frequency observation of a millisecond pulsar to date, and implies a luminosity at 17 GHz of 14 ?Jy kpc2, and a mean spectral index of 2.2. We find that the spectral index of the magnetar PSR J1622-4950 is flat between 1.4 and 24 GHz, similar to the other known radio magnetars XTE J1810-197 and 1E 1547.0-5408. The profile is similar to that at 3.1 GHz, and is ...
2011-06-01
(/sup 14/C)sucrose uptake and labeling of starch in developing grains of normal segl barley
Energy Technology Data Exchange (ETDEWEB)
Previous work showed that the segl mutant of barley (Hordeum vulgare o Betzes) did not differ from normal Betzes in plant growth, photosynthesis, or fertility, but it produced only shrunken seeds regardless of pollen source. To determine whether defects in sucrose uptake or starch synthesis resulted in the shrunken condition, developing grains of Betzes and segl were cultured in (/sup 14/C)sucrose solutions after slicing transversely to expose the endosperm cavity and free space. In both young grains (before genotypes differed in dry weight) and older grains (17 days after anthesis, when segl grains were smaller than Betzes), sucrose uptake and starch synthesis were similar in both genotypes on a dry weight basis. To determine if sucrose was hydrolyzed during uptake, spikes of Betzes and segl were allowed to take up (fructose-U-/sup 14/C)sucrose 14 days after anthesis and the radioactivity of endosperm sugars was examined during 3 hours of incubation. Whereas less ...
1984-01-01
Transient optical and electrical effects in polymeric semiconductors
Energy Technology Data Exchange (ETDEWEB)
Classical semiconductor physics has been continuously improving electronic components such as diodes, light-emitting diodes, solar cells and transistors based on highly purified inorganic crystals over the past decades. Organic semiconductors, notably polymeric, are a comparatively young field of research, the first light-emitting diode based on conjugated polymers having been demonstrated in 1990. Polymeric semiconductors are of tremendous interest for high-volume, low-cost manufacturing (''printed electronics''). Due to their rather simple device structure mostly comprising only one or two functional layers, polymeric diodes are much more difficult to optimize compared to small-molecular organic devices. Usually, functions such as charge injection and transport are handled by the same material which thus needs to be highly optimized. The present work contributes to expanding the knowledge on the physical mechanisms determining ...
2009-05-28
We describe the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Early Release Science (ERS) observations in the GOODS-South field. The new WFC3 ERS data provide calibrated, drizzled mosaics with FHWM=0.07--0.15" in the near-UV (filters F225W, F275W, and F336W) and near-IR (F098W, F125W, and F160W) in typically 2 orbits per filter. Together with the existing HST/ACS GOODS-S mosaics in the BVi'z' filters, the 10-band ERS data cover 40-50 sq. arcmin to AB=26-27.0 mag (10-sigma for point sources). In this poster, we describe the: (1) scientific rationale, data taking and reduction procedures of the WFC3 ERS mosaics; (2) object cataloging and star-galaxy separation techniques used in these 10 different filters; (3) reliability and completeness of the 10-band object catalogs from the ERS mosaics; (4) object counts in 10 different filters from 0.2-1.7 microns to AB=26.0-27.0 mag; and (5) the full-color 10-band ERS images. We discuss the panchromatic structure for a variety of ...
2010-01-01
Activity patterns in elementary and high school students exposed to oxidant pollution
Energy Technology Data Exchange (ETDEWEB)
We investigated activity patterns of 17 elementary school students aged 10-12, and 19 high school students aged 13-17, in suburban Los Angeles during the oxidant pollution season. Individuals' relationships between ventilation rate (VR) and heart rate (HR) were calibrated' in supervised outdoor walking/jogging. Log VR was consistently proportional to HR; although calibrations' were limited by a restricted range of exercise, and possibly by artifact due to mouthpiece breathing, which may cause overestimation of VR at rest. Each subject then recorded activities in diaries, and recorded HR once per minute by wearing Heart Watches, over 3 days (Saturday-Monday). For each activity the subject estimated a breathing rate--slow (slow walking), medium (fast walking), or fast (running). VR ranges for each breathing rate and activity type were estimated from HR recordings. High-school students' diaries showed their aggregate distribution of waking hours as 68% ...
1992-07-01
Energy Technology Data Exchange (ETDEWEB)
We present the first 3.8 {micro}m image of the dusty ring surrounding the young binary system GG Tau, obtained with the W. M. Keck II 10m telescope's adaptive optics system. THis is the longest wavelength at which the ring has been detected in scattered light so far, allowing a multi-wavelength analysis of the scattering proiperties of the dust grains present in this protoplanetary disk in combination with previous, shorter wavelengths, HST images. We find that the scattering phase function of the dust grains in the disk is only weakly dependent on the wavelength. This is inconsistent with dust models inferred from observations of the interstellar medium or dense molecular clouds. In particular, the strongly forward-throwing scattering phase function observed at 3.8 {micro}m implies a significant increase in the population of large ({approx}> 1 {micro}m) grains, which provides direct evidence for grain growth in the ring. However, the grain size ...
2004-02-04
STRUCTURE AND FORMATION OF ELLIPTICAL AND SPHEROIDAL GALAXIES
International Nuclear Information System (INIS)
New surface photometry of all known elliptical galaxies in the Virgo cluster is combined with published data to derive composite profiles of brightness, ellipticity, position angle, isophote shape, and color over large radius ranges. These provide enough leverage to show that Sersic log I #propor to# r "1"/"n functions fit the brightness profiles I(r) of nearly all ellipticals remarkably well over large dynamic ranges. Therefore, we can confidently identify departures from these profiles that are diagnostic of galaxy formation. Two kinds of departures are seen at small radii. All 10 of our ellipticals with total absolute magnitudes M_V_T #<=# -21.66 have cuspy cores-"missing light"-at small radii. Cores are well known and naturally scoured by binary black holes (BHs) formed in dissipationless ("dry") mergers. All 17 ellipticals with -21.54 #<=# M_V_T #<=# -15.53 do not have cores. We find a new distinct component in these galaxies: all coreless ellipticals in our sample have ...
2009-05-01
Energy Technology Data Exchange (ETDEWEB)
In the future even more than in the past, nuclear power will be indispensable in the present industrialized countries and in those still under development. The safe, nonpolluting, and economic supply of energy to mankind in the future includes so many different problems that the technology of the high-temperature reactor at its present level of development, and with the possibilities is offers above and beyond those provided by other, established, technologies, does not have to mark the end of some old line of development, but rather should be seen as the starting point of a development offering promise for the future. It is for this very reason that the extensive, valuable knowledge and experience accumulated in the construction, operation, and decommissioning of the AVR and THTR plants, the development of the HTR module and other variants and, last, but not least, the valuable results of projects such as PNP, NFE, and HHT, must be preserved at the research centers and with former ...
1996-08-01
The Path to Fusion Energy for Concepts Currently at the Concept Exploration Level
Energy Technology Data Exchange (ETDEWEB)
Concept Exploration (CE) experiments within the Innovative Confinement Concept Program have a unique role which impacts their contributions to the development of fusion energy. As stated in the FESAC ''Report on Alternate Concepts:'' These [CE] programs are aimed at innovation and basic understanding of relevant scientific phenomena. The emphasis on innovation motivates their application to the search for a better fusion reactor configuration. In addition, because of their unique character the CE experiments offer excellent opportunities to couple fusion-plasma physics to other sciences. A recent example of coupling is the fusion self-organized plasmas to reconnection physics and extra-terrestrial plasmas. Perhaps of even greater importance is the education of the future scientists needed for developing fusion energy. The CE experiments, both at universities and national labs, are of a size students can ''get their hands ...
2003-01-09
40th Anniversary of the First Proton-Proton Collisions in the CERN Intersecting Storage Rings (ISR)
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