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We investigate the spectral and temporal behavior of the high mass X-ray binary Vela X-1 during a phase of high activity, with special focus on the observed giant flares and off states. INTEGRAL observed Vela X-1 in a long almost uninterrupted observation for two weeks in 2003 Nov/Dec. The data were analyzed with OSA 7.0 and FTOOLS 6.2. We derive the pulse period, light curves, spectra, hardness ratios, and hardness intensity diagrams, and study the eclipse. In addition to an already high activity level, Vela X-1 exhibited several intense flares, the brightest ones reaching a maximum intensity of more than 5 Crab in the 20-40 keV band and several off states where the source was no longer detected by INTEGRAL. We determine the pulse period to be 283.5320+/-0.0002 s, which is stable throughout the entire observation. Analyzing the eclipses provided an improvement in the ephemeris. Spectral analysis of the ...

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PMID:13363598

Science.gov (United States)

It is shown that there may be a correlation between the galactic cosmic rays and the solar neutrino

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Hard X-ray/gamma-ray spectrometers aboard two interplanetary spacecraft, Ulysses and Pioneer Venus Orbiter (PVO), and two near-Earth spacecraft, Yohkoh and Compton Gamma Ray Observatory (GRO/BATSE), are currently in operation. A unique set of circumstances have permitted the observation of the 15 November 1991 (2238 UT) flare by all the four instruments. This intense flare (GOES class X 1.5) was associated with the bright (3B) H-alpha flare located on the disk (S13, W19) in the active region 6919. At the time of the flare, the Ulysses and PVO spacecraft were located respectively 101[degree] and 52[degree] west of the Sun-Earth line. Thus the view angles for the PVO and Ulysses instruments were quite different from those of the near-Earth instruments on GRO and Yohkoh. The preliminary photon energy spectra observed by the four instruments at different times during the flare will be ...

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... electrons fine structure giant resonance inelastic scattering iron 54 iron 54

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... I3a. -YPE OF REPORT T7b 7,ME COVEE 14 DATE OF REPORT (Year, Month. ... the addition of various materials to the standard flare in order to ...

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The determination of Li and proton-capture element abundances in globular cluster (GC) giants allows us to constrain several key questions on the multiple population scenarios in GCs, from formation and early evolution to pollution and dilution mechanisms. In this Letter, we present our results on Li abundances for a large sample of giants in the intermediate-metallicity GC NGC 6121 (M4), for which Na and O have been already determined by Marino et al. The stars analyzed are both below and above the red giant branch bump luminosity. We found that the first and second generation stars share the same Li content, suggesting that a Li production must have occurred. This provides strong observational evidence supporting the scenario in which asymptotic giant branch stars are GC polluters.

UK PubMed Central (United Kingdom)

Although deep-sea cephalopods are key marine organims, their feeding ecology remains essentially unknown. Here, we report for the first time the trophic structure of an assemblage of these animals (19...Full Text Available

UK PubMed Central (United Kingdom)

During attempts to establish tissue cultures from hepatopancreas, heart, and hemolymph of the giant tiger prawn (Penaeus monodon), using a medium including penicillin, streptomycin, and amphotericin...Full Text Available

UK PubMed Central (United Kingdom)

The rate of survival for infants with intact giant exomphatos has much improved during the last 20 years; this is partly due to better respiratory and nutritional support. The use of a staged operative...Full Text Available

UK PubMed Central (United Kingdom)

Four cases of unilateral giant breasts from two unrelated families are described. Three of the patients were managed surgically. It is speculated from a review of available published reports that this...Full Text Available

International Nuclear Information System (INIS)

Three classes of solar emanations, namely, photon radiation from solar flares, solar energetic particles, and inhomogeneities in the solar wind that drive magnetic storms, are examined, and their effects on humans and technological systems are discussed. Solar flares may disrupt radio communications in the HF and VLF ranges. Energetic particles pose a special hazard at low-earth orbit and above, where they can penetrate barriers such as spacesuits and aluminum and destroy cells and solid state electronics. Energetic solar particles also influence terrestrial radio waves propagating through polar regions. Magnetic storms may disturb the operation of navigation instruments, power lines and pipelines, and satellites; they give rise to ionospheric storms which affect radio communication at all latitudes. There is also a growing body of evidence that changes in the geomagnetic field affect biological systems. 3 refs.

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Results are presented of an empirical analysis of the global thermodynamical requirements of the winds in the outer atmospheres of a representative sample of red giant stars of low- and intermediate-mass range. Results indicate that the mass-loss rates in these stars are not strongly dependent on the actual physical processes driving the winds. It is suggested that nonlinear processes act to regulate wind energy fluxes. Possible mechanisms responsible for the chromospheric heating and the mass loss in the low- and intermediate-mass giant stars are discussed. 151 refs.

CERN Document Server

The nature of the hard X-ray source XSSJ12270-4859 is still unclear though it was claimed to be a magnetic Cataclysmic Variable. We here present a broad-band X-ray and gamma ray study based on a recent XMM-Newton observation and archival INTEGRAL and RXTE data. From the Fermi/LAT 1-year point source catalogue, we tentatively associate XSSJ12270-4859 with 1FGLJ1227.9-4852, a source of high energy gamma rays with emission up to 10GeV. We complement the study with UV photometry from XMM-Newton and ground-based optical and near-IR photometry. The X-ray emission is highly variable showing flares and intensity dips. The X-ray flares consist of flare-dip pairs. Flares are also detected in the UV range but not the dips. Aperiodic dipping behaviour is also observed during X-ray quiescence but not in the UV. The 0.2-100keV spectrum is featureless and described by a power law model with Gamma=1.7. The 100MeV-10GeV ...

Science.gov (United States)

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 ...

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... Garlic mustard Alliaria petiolata 4 Common (lesser) burdock Arctium minus 6 Giant reed Arundo donax 7 ... Common (lesser) burdock (Arctium minus) ...

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Aug 23, 2011 ... Earthquakes, Hurricanes and Stubborn Instruments ... And if earthquakes and stubborn instruments aren't enough, there's this giant hurricane ...

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Proton and alpha decay from the giant resonance region of {sup 28}Si excited with a 129 MeV alpha particle beam has been measured in coincidence with inelastic alpha particles detected at 0{degree}. The angular correlation data show the presence of decay from both {ital E}0 and {ital E}2 giant resonances. The {ital E}0 giant resonance decays primarily through the {alpha}{sub 0}, {alpha}{sub 1}, {ital p}{sub 0}, and {ital p}{sub 1,2} channels with the branching ratios 18{plus minus}6 %, 24{plus minus}8 %, 23{plus minus}9 %, and 18{plus minus}8 %, respectively. Substantial direct decay is observed.

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Mar 6, 2009 ... remnants of massive star evolution) to worlds that are more reassuringly familiar. In the latter category, we now have excellent evidence ...

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for massive star evolution, or they could all be very blue super- giant stars experiencing A , = 1-1.5 mag. The fact that the en- ...

CERN Document Server

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 ...

UK PubMed Central (United Kingdom)

Electrically triggered action potentials in the giant alga Chara corallina are associated with a transient rise in the concentration of free Ca²+ in the cytoplasm (Ca²+_cyt)....Full Text Available

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Giant magnetoresistance (GMR) has been used with Eddy current testing to detect small defects not only in thin film structures but also in multilayered metallic structures. This work detected small scratches in the thin film under the surface where these defects were unable to be inspected or monitored by regular testing. In addition, rotational GMR magnetic sensor based Eddy current probes were used for detecting buried corner cracks at the edge of holes in metallic structures. The results of this study proved that giant magnetoresistance is very powerful and effective to sense the magnetic field, which is the result from the perturbation of the Eddy currents caused by a defect. This method can be used for quality control of metallization layers on silicon wafer and to detect cracks in thick structures such as cracks in aging aircraft.

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Formulas are obtained for calculation of the energies and B(Elambda) values of T/sub greater-than/ giant resonances in the quasiparticle-phonon model of the nucleus. Characteristics of giant dipole resonances are calculated in several spherical nuclei and the correct location is obtained for T/sub less-than/ and T/sub greater-than/ collective 1/sup -/ states. The calculated ratios sigma/sub -/1(T/sub greater-than/)/sigma/sub -/1(T/sub less-than/) agree with the experimental data for /sup 88/Sr, /sup 90/Zr, and /sup 92/Mo and are 3 times larger than the experimental values for /sup 116,120,124/Sn. The decrease of the cross sections sigma/sub -/1(T/sub greater-than/) in /sup 124/Sn in comparison with /sup 116/Sn is correctly reproduced.

CERN Document Server

Context: Our previous models of a giant planet migrating through an inner protoplanet/planetesimal disk find that the giant shepherds a portion of the material it encounters into interior orbits, whilst scattering the rest into external orbits. Scattering tends to dominate, leaving behind abundant material that can accrete into terrestrial planets. Aims: We add to the possible realism of our model by simulating type I migration forces which cause an inward drift, and strong eccentricity and inclination damping of protoplanetary bodies. This extra dissipation might be expected to enhance shepherding at the expense of scattering, possibly modifying our previous conclusions. Methods: We employ an N-body code that is linked to a viscous gas disk algorithm capable of simulating: gas accretion onto the central star; gap formation in the vicinity of the giant planet; type II migration of the giant planet; type ...

UK PubMed Central (United Kingdom)

Six related Staphylococcus phages spontaneously produced various abnormal head and tail structures: (i) giant capsids which were tailed and apparently contained nucleic acid; (ii) regular and irregular...Full Text Available

International Nuclear Information System (INIS)

The primary E1, M1 and E2 #gamma#-radiation in "8"7","8"8","8"9Sr observed after thermal neutron capture was compared with the predictions of single particle and giant resonance models. The nuclei feature a wide range of neutron binding energies between 6.3 and 11.1 MeV, which makes a 5.5 MeV spectrum of primary transition energies available for investigation. The (n, #gamma#) reaction was used to estimate the parameters of the spin-flip M1 giant resonance in strontium. The total energy weighted M1 strength of this resonance exceeds the results of shell model and random phase approximation calculations for "9"0Zr by a factor of 3-4. The E1 strengths were found to agree with the established giant dipole resonance model. The few data on primary E2 transitions do not allow to differentiate between the giant quadrupole resonance and the single particle models. (orig.).

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Rapamycin inhibits the mTOR (target of rapamycin) pathway and extends lifespan in multiple species. The tuberous sclerosis complex (TSC) protein is a negative regulator of mTOR. In humans, loss of the...Full Text Available

International Nuclear Information System (INIS)

The possibility to compress and to split laser pulses at their nonlinear optical transmission through semiconductor films was investigated

UK PubMed Central (United Kingdom)

Genome endoreduplication during mammalian development is a rare event for which the mechanism is unknown. It first appears when fibroblast growth factor 4 (FGF4) deprivation induces differentiation...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundMimivirus, a giant dsDNA virus infecting Acanthamoeba, is the prototype of the mimiviridae family, the latest addition to the family of the nucleocytoplasmic...Full Text Available

UK PubMed Central (United Kingdom)

Alton Ochsner was a giant of American surgery. His career encompassed patient care, teaching, and research as symbolized on the original seal of the Ochsner Clinic. His ideas were innovative and groundbreaking...Full Text Available

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The mechanism of abrupt increase of the giant magneto impedance (GMI) ratio in the ion irradiated Co-based amorphous ribbon has been investigated. The grazing incident X-ray diffraction and transmission electron microscope were used to characterize the samples before and after ion irradiation. The GMI-ratio considerably increased in the ion irradiated samples and the GMI response showed strong dependence on the driving frequencies. The Barkhausen noise (BN) signals are increased for the Ar ion irradiated sample with dose of 1x10^1^7 ion/cm^2. The results are interpreted in terms of GMI variation associated with domain wall dynamics.

International Nuclear Information System (INIS)

The US study of the posterior compartment of the knee usually allows the clinical suspicion of popliteal cyst to be confirmed. Neverthless, in case of giant Baker's cysts - which are, at any rate, less frequent -US diagnosis is more difficult. CT can help determine the benign nature of the lesion, and hallow an accurate spatial evaluation. Moreover CT, when accurately performed, demonstrates the caudal or cranial cystic spread, together with its clear separation from adjacent muscular tissues. Direct coronal scans are more useful to obtain better spatial definition than reformatted images.

CERN Document Server

A fundamental and very well studied region of the Erd\\"os-R\\'enyi process is the phase transition at n/2 edges in which a giant component suddenly appears. We examine the process beginning with an initial graph. We further examine the Bohman-Frieze process in which edges between isolated vertices are more likely. While the positions of the phase transitions vary, the three processes belong, roughly speaking, to the same universality class. In particular, the growth of the giant component in the barely supercritical region is linear in all cases.

CERN Document Server

Three red giants (HD 49566 (G5III), HD 169370 (K0III) and HD 169751 (K2III)) have been observed in the CoRoT seismo field and additional ground-based spectra have been acquired. We present preliminary results of a detailed study of these stars using the observational constraints from the spectra and CoRoT data, and models from the YREC stellar evolution code.

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We present a forward modelling technique for calculating the surface X-ray spectra for a variety of lunar terrains. Our calculations considered variations in solar fluxes from solar quiescent condition to large flare activity (M1 flare), and expected elemental concentrations in the target, as well as yield, instrumental, and viewing geometry parameters for X-ray induced fluorescence from the lunar surface. Additionally, we present estimates of anticipated XRF signals from prominent Ka lines observable by a collimated 14cm2 X-ray detector from a 100km lunar orbit with 20km spatial resolution. Our results show that Mg, Al and Si characteristic Ka lines can be observed for all solar conditions. The Ca Ka lines line can be differentiated from a fixed background during more energetic solar cond...

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Dynamic quantitative bone scintigraphy was performed on 31 men with prostatic carcinoma before orchiectomy as well as 2 weeks, 2 and 6 months postoperatively. After injection of technetium methylene diphosphonate Tc 99m ("9"9"mTc-MDP) the count rate was recorded as serial images over the lower thoracic and all the lumbar vertebrae from 1 to 240 min post-injection. Thirteen men had normal bone scintigrams with no changes in "9"9"mTc-MDP content at the four different investigation times. Eighteen men had skeletal metastases. Throughout the study half of the abnormal vertebrae in these patients showed an abnormal count rate after only 6 min post-injection. After 1 h it was possible in almost all abnormal vertebrae to predict abnormal bone uptake. In response to therapy a 'flare phenomenon' with an increase in count rate was seen 2 weeks after orchiectomy followed by a decrease 2 months postoperatively in most of the abnormal vertebrae. The count rate decreased even ...

British Library Electronic Table of Contents (United Kingdom)

Green Lake Landslide is an ancient giant rock slide in gneiss and granodiorite located in the deeply glaciated Fiordland region of New Zealand. The landslide covers an area of 45km2 and has a volume of about 27km3. It is believed to be New Zealands largest landslide, and possibly the largest landslide of its type on Earth. It is one of 39 known very large (106-107 m3) and giant (?108m3) postglacial landslides in Fiordland discussed in the paper. Green Lake Landslide resulted in the collapse of a 9km segment of the southern Hunter Mountains. Slide debris moved up to 2.5km laterally and 700m vertically, and formed a landslide dam about 800m high, impounding a lake about 11km long that was eventually infilled with sediments. Geomorphic evidence supported by radiocarbon dating indicates tha...

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The presence of two major aminopeptidases (aminopeptidases I and II) in the giant alga Chara australis was shown using polyacrylamide gel electrophoresis. Partially purified aminopeptidase I had a molecular weight of about 120,000, hydrolyzed both leucine-?-naphthylamide (pH optimum 6.0) and alanine-?-naphthylamide (pH optimum 7.5), and was located both inside and outside the vacuole. Aminopeptidase I was inhibited by p-chloromercuribenzoic acid, iodoacetic acid, 1,10-phenanthroline, and N-tosyl-l-phenylalanine chloromethyl ketone. Aminopeptidase II hydrolyzed alanine-?-naphthylamide but not leucine-?-naphthylamide and was located only outside the vacuole.ImagesFig. 1Fig. 2Fig. 4Fig. 5

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Since some of the earliest evolutionary calculations it has been found that post main sequence stars become red giants (e.g. Sandage and Schwarzschild, 1952). However the exact physical processes that lead to and determine the rate of redward evolution are not completely understood. We hypothesized that the redward evolution might be due to an increase in radiation pressure somewhere in the star that causes the layers above it to be pushed outward, resulting in an expanded envelope and a cooler surface temperature. If the radiative luminosity somewhere in the star approached the Eddington limit, the outer layers would obviously expand. However, due to the presence of gas pressure, the critical value for expansion would be somewhat less than the Eddington limit.

British Library Electronic Table of Contents (United Kingdom)

Field-annealed Co-based amorphous ribbon (Metglas? 2705M) with a meander structure is fabricated by MEMS technology and the giant magnetoimpedance (GMI) effects are studied at different magnetic fields and frequencies. The maximum longitudinal GMI ratio of the ribbon is 193.7% and the magnetic field sensitivity is 17.4%/Oe. The maximum GMI ratio of the meander ribbon is much larger than the single strip ribbon mainly due to the larger change ratio of inductance L. The sensitivity of an output U reach up to 10 V/A and U thermal fluctuation is less than 15 mV in the temperature range of ?20 to 40?C. This meander shape ribbon can be considered as a good candidate for the GMI-based sensor fabrication.

British Library Electronic Table of Contents (United Kingdom)

? Introduction For large trees without a continuous sequence of growth rings in their trunk, such as the African baobab (Adansonia digitata L.), the only accurate method for age determination is radiocarbon dating. As of today, this method was limited to dating samples collected from the remains of dead specimens. ? Methods Our research extends significantly the dating of such trees to large live specimens with inner cavities. The new approach is based on collecting samples from the cavities and their subsequent radiocarbon dating. ? Results The giant two-stemmed Platland tree, also known as Sunland baobab, was investigated by using this new approach. AMS radiocarbon dates of the oldest sample segments originating from the two inner cavities indicate that the large stem I (364.5?m3) is 750...

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Contents include: index for 1970-1980; January 1981 data -- alert periods, daily solar indices, solar flares, solar radio emission, coronal holes, inferred interplanetary magnetic field polarities, mean solar magnetic field, spacecraft observations, December 1980 data -- daily solar-activity centers, sudden ionospheric disturbances, spacecraft observations, solar radio emission, cosmic rays, geomagnetic indices, radio-propagation indices; late data -- solar radio emission November, December 1980, spacecraft observations November 1980, cosmic rays, Huancayo Oct 1980 -- climax, alert, Deep River Nov 1980.

Science.gov (United States)

Apparent evolution of relativistic flows as traced by radio emission results from a combination of several factors related to propagation of relativistic blobs or shocks, velocity, density and pressure stratification of the underlying flow, plasma instability and (possibly also) phase and time travel effect. This combination can create an intricate and chaotic patterns of the observed morphological changes in radio emission, which complicates the analysis and interpretation of kinematic and physical properties of the jet plasma. Recent studies have indicated that slow and quasi-stationary patterns in jets are most likely formed by plasma instabilities while faster, superluminally moving patterns are related to highly relativistic plasma condensations produced by the nuclear flares. Some of the stationary patterns may also be related to recollimation shocks or locations where strong non-thermal continuum is produced in jets. Similarities and differences of the AGN ...

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Abstract Smoke is a mixture of toxic gases and suspended particulate matter of solids and liquids that evolves from a fire of flammable materials. This article presents real-time consequence modeling to track the concentration of individual species in smoke as well as its soot deposition. In the modeling process presented, the burning rate or vapor mass is fed into a combustion model in which the combustion of products has been identified and quantified along with the temperature of the fire. The output of the combustion model is the smoke that will be dispersed into the ambient. The fire geometry, which depends on the type of fire (e.g., pool or flare), is identified. A dispersion model with the capability of determining particulate deposition is then used for tracking the smoke plume. Th...

International Nuclear Information System (INIS)

Since the commissioning of the first 10 strings of the AMANDA neutrino telescope, more than nine years of data has been collected. The proof of principle of high-energy neutrino detection in ice is established. No positive signal of an extra-terrestrial high-energy neutrino flux have been found so far. However, the most stringent upper limits to the flux of cosmic neutrinos-respectively, diffuse, point like or associated with gamma-ray bursts-have been presented. A sample of 3329 up-going muon tracks, representing the largest statistics ever of high-energy neutrino induced events, has been collected between 2000 and 2003. A coincidence of neutrino with an anomalous high-energy gamma-ray flare has been observed from the direction of the Blazar 1ES1959+650-although the observation were not conclusive. Selected results of data taken with the AMANDA detector are here reported.

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To understand the evolution of giant stars, it is important to pin down the masses for Cepheids. The 7- to 10-day bump Cepheids imply lower than evolutionary mass (60%). Recent theoretical work, though, indicates that for Cepheids with periods of 15 to 16 days, the best understanding of the light curves results from using evolutionary masses.

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The giant resonance regions of {sup 90}Zr, {sup 116}Sn, {sup 144}Sm and {sup 208}Pb were investigated using 240 MeV {alpha} particle scattering at small angles including 0 deg. E1 strengths corresponding to 91{+-}11%, 89{+-}10%, 105{+-}12% and 95{+-}13% of the isoscalar E1 energy-weighted sum rule were identified between 18{<=}E{sub x}{<=}31 MeV, 16{<=}E{sub x}{<=}30 MeV, 15{<=}E{sub x}{<=}27 MeV and 15{<=}E{sub x}{<=}25 MeV with centroid energies of 24.8{+-}0.4 MeV, 22.5{+-}0.3 MeV, 21.6{+-}0.3 MeV and 19.3{+-}0.3 MeV and rms widths of 3.2{+-}0.2 MeV, 3.5{+-}0.2 MeV, 3.2{+-}0.2 MeV and 2.5{+-}0.2 MeV for {sup 90}Zr, {sup 116}Sn, {sup 144}Sm and {sup 208}Pb, respectively. Parameters obtained for the isoscalar giant monopole resonance, isoscalar giant quadrupole resonance and high energy octupole resonance are in agreement with accepted values.

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High resolution imagery of the clumpy irregular galaxy Mkn 325 shows that some clumps have sizes approximately 300 pc while some may still be unresolved and approximately < 100 pc. In spite of dimensions comparable to - or even smaller than - those of the giant H II complex 30 Doradus, one clump has a star formation rate 100 times higher.

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Abstract Adult rhabdomyoma is a rare primary benign tumour of striated muscle origin that almost exclusively presents in the head and neck region with predilection for male. We herein report a case of an adult rhabdomyoma in a 67-year-old male with cytologic features. The lesions was located in the tongue extended to the left parapharyngeal region. We discuss the cytological findings with a brief review of the literature on this entity. Diagn. Cytopathol. 2010. 2010 Wiley-Liss, Inc.

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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.

Science.gov (United States)

The giant alga Chara corallina generates action potentials (APs) in response to mechanical stimulation, injury, or direct electrical stimulation. Students examine the waveform characteristics of these APs using standard intracellular recording techniques. Intracellular recording is easier than with neurons because of the large size of the Chara cell. Students observe very negative resting potentials (up to -250 mV), large AP amplitudes with depolarizing peaks approaching 0 mV, AP durations of seconds, and refractory periods up to several minutes. Students calculate Nernst potentials for the ions distributed across the Chara cell membrane to hypothesize the ions responsible for the resting potential and for the depolarizing phase of the AP. These calculations suggest that K+ is responsible for the resting potential and that Ca2+ influx and Ca2+-activated Cl- efflux are responsible for depolarizing phases of the AP, which they are. Comparison of the Chara AP ...

International Nuclear Information System (INIS)

After presenting a general account of the observed global properties of single stars of low, intermediate, and high mass, together with their theoretical Hertzsprung-Russell diagram evolution, attention is given to the observed properties of various evolved close binaries and to an assessment of the value of comparisons between observation and crude theory in characterizing the physics of mass transfer within interacting binary systems. Detailed consideration is then undertaken of such topics as stellar evolution in globular clusters, interior star changes due to nucleosynthesis and mixing, asymptotic giant branch stars of intermediate mass, the response of white dwarfs in binary systems to mass accretion, and scenarios for binary star evolution tending toward close white dwarf pairs.

International Nuclear Information System (INIS)

Several recent experiments on micro- (or nano-) structured samples of ferromagnetic materials are introduced. Magnetization reversal phenomena are investigated on submicron wire samples of trilayer structure using the giant magnetoresistance effect. Domain wall movements are sensitively monitored by resistivity measurements and the velocity of propagation is determined. The contribution of domain wall to the resistivity is argued from the results on artificially designed samples of a spring-magnet system. In circular dots of permalloy, the existence of vortex magnetization is confirmed and the reversal of the vortex core magnetization is studied from magnetic force microscopy measurements. (author)

CERN Document Server

CH Cygni is a symbiotic star consisting of an M giant and an accreting white dwarf, which is known to be a highly variable X-ray source with a complex, two-component, spectra. Here we report on two Suzaku observations of CH Cyg, taken in 2006 January and May, during which the system was seen to be in a soft X-ray bright, hard X-ray faint state. Based on the extraordinary strength of the 6.4 keV fluorescent Fe K-alpha line, we show that the hard X-rays observed with Suzaku are dominated by scattering.

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Ordos Basin, the second largest sedimentary basin in China, contains enormous natural gas resources. Each of the four giant gas fields discovered so far in this basin (i.e., Sulige, Yulin, Wushenqi and Jingbian) has over 100 billion cubic meters (bcm) or 3.53 trillion cubic feet (tcf) of proven gas reserves. This study examines the stable carbon isotope data of 125 gas samples collected from the four giant gas fields in the Ordos Basin. Source rocks in the Upper Paleozoic coal measures are suggested by the generally high {delta}{sup 13}C values of C{sub 2}-C{sub 4} gaseous hydrocarbons in the gases from the Sulige, Yulin and Wushenqi gas fields. The {delta}{sup 13}C values of methane, benzene and toluene in gases from the Lower Paleozoic reservoirs of the Jingbian field indicate a significant contribution from humic source rocks, as they are similar to those in the Upper Paleozoic reservoirs of the Sulige, Yulin and Wushenqi gas fields. ...

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Electrical heating of subsea flowlines is an effective way to prevent wax and hydrate information, especially for long transportation distances and in low-temperature deep water. Systems are available for use in conjunction with bundles, pipe-in-pipe, and wet-thermal-insulation systems. These systems provide environmentally friendly fluid-temperature control without chemicals or flaring for pipeline depressurizing. Enhanced production is achieved because no time is lost by unnecessary depressurizing, pigging, heating-medium circulation, or removal of hydrate and wax blockages. The seabed temperature at 100-m and greater water depths may range from 7 to {minus}1.5 C, causing a rapid cooling of the hot well streams being transported in subsea flowlines. Under these supercooling conditions, vulnerable crude oils and multiphase compositions will deposit wax and asphalts; also the gas/water phase may freeze solid with hydrate particles. The paper discusses ...

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The synchronous orbit performance of Hughes Aircraft Company solar arrays is presented and compared with the results of ground based predictions for orbital durations of almost 11 years. Performances of the Intelsat IV*, IVA*, and Telesat (Anik) solar arrays are detailed. This paper is an update of the in-orbit performances previously reported in 1976 (1). The in-space performance data indicate solar array power degradation of 16.7 percent for Intelsat IV F-2 after 130 months in orbit, and 13.0 percent for Telesat F-1 after 85 months in orbit. The predicted output of each of these solar arrays is within 2 percent of the actual in-orbit performance of these systems. The Intelsat IV F-2 experienced the 4 August 1972 solar flare. The ability to accurately predict the performance of solar arrays within telemetry accuracy is demonstrated. This ability combines the electrical measurements of a solar array in the ''as built'' ...

International Nuclear Information System (INIS)

Bone scintigraphy was performed in 16 men with newly diagnosed prostatic carcinoma before orchiectomy as well as 2 weeks and 2 months after operation. The uptake in the lower thoracic and lumbar vertebrae was registered up to 240 min after injection of "9"9"mTc-MDP and was then calculated for each patient and vertebra. The relative standard deviation in measured uptake due to measuring technique was estimated to be #+-#7%. In eight patients, who had normal bone scintigraphies before orchiectomy, there were no changes in the uptake values after operation. The remaining eight patients had widespread metastatic involvement prior to treatment, six of these patients showed a so-called 'flare phenomenon' in the abnormal vertebrae which means an initial increase in uptake after operation followed by a decreased uptake in response to therapy. One patient had a continuously increased uptake in all the abnormal vertebrae which correlated well with the clinical progression of ...

International Nuclear Information System (INIS)

Quantitative bone scintigraphy was performed in 24 patients with prostatic carcinoma before orchiectomy and up to one to four years after operation. The gamma camera count rate was recorded over the lower thoracic and all lumbar vertebrae 4 h after injection of "9"9"mTc-MDP. Twelve patients has normal bone scintigrams throughout the study. They showed from two years after operation a slight increase in count rate values compared with the preoperative values, probability due to hormonal changes after orchiectomy and to age-related alterations in skeletal metabolism. Twelve patients had abnormal bone scintigrams. They showed as a response to treatment the flare phenomenon with an increase in count rate over the abnormal vertebrae when measured two weeks after operation followed by a decrease after two months. The lowest count rate values were obtained between six months and one year after operation. Thereafter the count rate seemed to remain on the same level. An ...

International Nuclear Information System (INIS)

Thirty-four patients with prostatic carcinoma were studied with quantitative bone scintigraphy and whole-body counting (WBC) 1 and 24 h after injection of "9"9"mTc-MDP before as well as two weeks and two months after orchiectomy. Thirteen of the patients had normal bone scintigrams and WBR at the three different investigations; 21 had skeletal metastases. The latter showed throughout the study higher local gamma camera count rates as well as WBR values than the patiens with normal scintigrams. In these patients a ''flare phenomenon'', with an increase in count rate two weeks after orchiectomy followed by a decrease two months post-operatively, was seen with quantitative bone scintigraphy but not with WBC. However, WBC may be a valuable method indicating the total extent of skeletal metastases in the body, while quantitative bone scintigraphy is more accurate in the interpretation of individual skeletal metastases. (orig.).

CERN Document Server

Context. The I(15.01 A)/I(16.78 A) emission line intensity ratio in Fe XVII has been reported to deviate from its theoretical value in solar and stellar X-ray spectra. This is attributed to opacity in the 15.01 A line, leading to a reduction in its intensity, and was interpreted in terms of a geometry in which the emitters and absorbers are spatially distinct. Aims. We study the I(15.01 A)/I(16.78 A) intensity ratio for the active cool dwarf EV Lac, in both flare and quiescent spectra. Methods. The observations were obtained with the Reflection Grating Spectrometer on the XMM-Newton satellite. The emission measure distribution versus temperature reconstruction technique is used for our analysis. Results. We find that the 15.01 A line exhibits a significant enhancement in intensity over the optically thin value. To our knowledge, this is the first time that such an enhancement has been detected on such a sound statistical basis. We interpret this enhancement in ...

Energy Technology Data Exchange (ETDEWEB)

To evaluate the efficacy of newly designed covered and non-covered coated colorectal stents for colonic decompression. Twenty-six patients, (15 palliative cases and 11 preoperative) underwent treatment for the relief of colorectal obstruction using metallic stents positioned under fluoroscopic guidance. In 24 of the 26, primary colorectal carcinoma was diagnosed, and in the remaining two, recurrent colorectal carcinoma. Twenty-one patients were randomly selected to receive either a type A or type B stent; for the remaining five, type C was used. Type A, an uncovered nitinol wire stent, was lightly coated to ensure structural integrity. Type B (flare type) and C (shoulder type) stents were polyurethane covered and their diameter was 24 and 26mm, respectively. The rates of technical success, clinical success, and complications were analyzed using the chi-square test, and to analyse the mean period of patency, the Kaplan-Meier method was used. Thirty of 31 attempted ...

British Library Electronic Table of Contents (United Kingdom)

Abstract We analyse extinction maps of nearby giant molecular clouds to forge a link between driving processes of turbulence and modes of star formation. Our investigation focuses on cloud structure in the column density range above the self-shielding threshold of 1-mag AV and below the star formation threshold - the regime in which turbulence is expected to dominate. We identify clouds with shallow mass distributions as cluster forming. Clouds that form stars in a less clustered or isolated mode show a steeper mass distribution. Structure functions prove inadequate to distinguish between clouds of different star formation mode. They may, however, suggest that the turbulence in the average cloud is governed by solenoidal forcing. The same is found using the -variance analysis which also in...

CERN Document Server

We report Sr, Pd and Ag abundances for a sample of metal-poor field giants and analyze a larger sample of Y, Zr, and Ba abundances. The [Y/Zr] and [Pd/Ag] abundance ratios are similar to those measured for the r-process-rich stars CS 22892-052 and CS 31082-001. The [Pd/Ag] ratio is larger than predicted from the solar-system r-process abundances. The constant[Y/Zr] and [Sr/Y] values in the field stars places strong limits on the contributions of the weak s-process and the main s-process to the light neutron-capture elements. Stars in the globular cluster M 15 possess lower [Y/Zr] values than the field stars. There is a large dispersion in [Y/Ba]. Because the r-process is responsible for the production of the heavy elements in the early Galaxy, these dispersions require varying light-to-heavy ratios in r-process yields.

CERN Document Server

Spatial Fluorescence Cross Correlation Spectroscopy is a rarely investigated version of Fluorescence Correlation Spectroscopy, in which the fluorescence signals from differ-ent observation volumes are cross-correlated. In the reported experiments, two observation volumes, typically shifted by a few $\\mu$m, are produced, with a Spatial Light Modulator and two adjustable pinholes. We illustrated the feasibility and potentiality of this technique by: i) measuring molecular flows, in the range 0.2 - 1.5 $\\mu$m/ms, of solutions seeded with fluorescent nanobeads or rhodamine molecules (simulating active transport phenomenons); ii) investigating the perme-ability of phospholipidic membrane of Giant Unilamellar Vesicles versus hydrophilic or hydrophobic molecules (in that case the laser spots were set on both sides of the mem-brane). Theoretical descriptions are proposed together with a discussion about FCS based, alternative methods.

Energy Technology Data Exchange (ETDEWEB)

In this paper we discuss a number of astrophysical environments and how improved nuclear data could facilitate a better understanding of them. One area of interest includes proton and alpha-particle reactions with unstable nuclei which are necessary for understanding the nucleosynthesis and energy generation in hot hydrogen-burning environments. Efforts underway at LLNL and elsewhere to develop the technology for the measurement of these reaction rates are discussed. Heavy-element nucleosynthesis in the late stages of red-giant stars and supernovae requires a complete network of neutron capture rates and beta-decay rates for nuclei near and far from stability. Experimental and theoretical efforts at LLNL to supply the input data and to model the nucleosynthetic environments will be outlined. Suggestions are made as to which nuclear data are most critical for the various scenarios. 42 refs., 11 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

The observed inhibition of M4 transitions in A approx. 90 nuclei has represented a long standing theoretical problem. In particular by calculating first- and second-order configuration mixing contributions to the inhibited M4 lifetimes of /sup 89/Y and /sup 87/Sr, it is found that the first-order perturbative treatment of the residual interaction usually used in shell-model calculations is unjustified in this case. Using random-phase approximation techniques, the renormalization effects of collective (''giant'') M4 resonances in /sup 88/Sr on the low energy M4 transitions in /sup 89/Y and /sup 87/Sr are investigated. It is concluded that the observed retardation of M4 lifetimes in these nuclei is consistent with the manifestation of nuclear spin polarization.

International Nuclear Information System (INIS)

The resonant scattering of bremsstrahlung #gamma#-rays by a SrCO_3 target has been studied for #gamma#-ray energies of 5-11 MeV. Six #gamma#-transitions of energies between 6-8 MeV, which indicate six resonant states in "8"8Sr, were observed. The relative intensities of the resonantly scattered #gamma#-rays at 125 and 150"0 were found to be compatible only with the assignment of spin 1 to the six states. Radiative widths of the resonant states were deduced. The possibility that these states are components of the giant M1 resonance in "8"8Sr is discussed. (orig.).

International Nuclear Information System (INIS)

Spin-flip probabilities for "4"8Ca(p vector, n vector)"4"8Sc reveal that at 0"0 the apparent continuum under and adjacent to the Gamow-Teller giant resonance is also primarily 1"+ strength. A comparison of "4"0Ca(p vector,n vector)"4"8Sc shows no discernable signature of Gamow-Teller strength in the region -30 > Q(MeV) > -45. The spin-flip component of the dipole resonance for "4"0Ca is broader than the non-spin-flip component. (orig.).

Energy Technology Data Exchange (ETDEWEB)

This research deals with in the study of the use of innovating magnetic sensors in eddy current non destructive inspection. The author reports an analysis survey of magnetic sensor performances. This survey enables the selection of magnetic sensor technologies used in non destructive inspection. He presents the state-of-the-art of eddy current probes exploiting the qualities of innovating magnetic sensors, and describes the methods enabling the use of these magnetic sensors in non destructive testing. Two main applications of innovating magnetic sensors are identified: the detection of very small defects by means of magneto-resistive sensors, and the detection of deep defects by means of giant magneto-impedances. Based on the use of modelling, optimization, signal processing tools, probes are manufactured for these both applications.

CERN Document Server

A prescription is given for computing anomalous dimensions of single trace operators in SYM at strong coupling and large $N$ using a reduced model of matrix quantum mechanics. The method involves treating some parts of the operators as "BPS condensates" which, in certain limit, have a dual description as null geodesics on the $S^5$. In the gauge theory, the condensate is similar to a representative of the chiral ring and it is described by a background of commuting matrices. Excitations around these condensates correspond to excitations around this background and take the form of ``string bits" which are dual to the "giant magnons" of Hofman and Maldacena. In fact, the matrix model approach gives a {\\it quantum} description of these string configurations and explains why the infinite momentum limit suppresses the quantum effects. This method allows, not only to derive part of the classical sigma model Hamiltonian of the dual string (in the infinite momentum ...

Energy Technology Data Exchange (ETDEWEB)

The 66 fields discovered since the 1960s in the northern West Siberian basin contain at least 22 trillion m/sup 3/ (777 tcf) of proved gas, almost one-third of the world's reserves. Half of these fields are giants (> 85 billion m/sup 3/ or 3000 bcf of reserves). These include the largest and second-largest gas fields in the world-Urengoy (8.099 trillion m/sup 3/ or 286 tcf of gas) and Yamburg (4.81 trillion m/sup 3/ or 170 tcf of gas)-as well as most of the other ten largest gas fields in the world. The West Siberian basin occupies a 3.4-million km/sup 2/ (1.31-million mi/sup 2/) arctic lowland immediately east of the Ural Mountains, extending north under the Kara Sea. It is a composite basin, with Mesozoic-Cenozoic basin fill on top of a Paleozoic basin that overlies a crystalline Archean-Proterozoic framework. The productive zones in the northern basin are principally in the Neocomian section (at an average depth of 2800m or 9200 ft) and the ...

Science.gov (United States)

Electrically triggered action potentials in the giant alga Chara corallina are associated with a transient rise in the concentration of free Ca(2)+ in the cytoplasm (Ca(2)+(cyt)). The present measurements of Ca(2)+(cyt) during membrane excitation show that stimulating pulses of low magnitude (subthreshold pulse) had no perceivable effect on Ca(2)+(cyt). When the strength of a pulse exceeded a narrow threshold (suprathreshold pulse) it evoked the full extent of the Ca(2)+(cyt) elevation. This suggests an all-or-none mechanism for Ca(2)+ mobilization. A transient calcium rise could also be induced by one subthreshold pulse if it was after another subthreshold pulse of the same kind after a suitable interval, i.e., not closer than a few 100 ms and not longer than a few seconds. This dependency of Ca(2)+ mobilization on single and double pulses can be simulated by a model in which a second messenger is produced in a voltage-dependent manner. This second messenger ...

Energy Technology Data Exchange (ETDEWEB)

This spring, Newfoundland will send off a floating production, storage and offloading (FPSO) vessel to the offshore Terra Nova field. The Terra Nova will proceed southeast through Bull Arm, then northeast out of Trinity Bay, then heads southeast to the Jeanne d'Arc Basin on the Grand Banks. The Terra Nova is expected to produce 115,000 barrels of oil per day for six years, when it reaches full capacity. The consortium, headed by Petro-Canada as senior ownership partner and operator, built an environment protection program into every aspect of the project. Some of the features of the environment protection program include glory holes excavated on the ocean floor for the protection of production equipment from icebergs, to a flare stack on the platform, which has four legs to provide stability in rough seas. The FPSO was designed to withstand sea ice, icebergs, and severe winter storms. Flow lines are also protected, and in the event that a line is damaged, ...

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. is a transient upset ...

Energy Technology Data Exchange (ETDEWEB)

As part of The International Northern Sea Route Programme (INSROP), Subprogram III, Trade and Commercial Shipping, a study has been made concerning seaborne export of liquefied petroleum gas (LPG) from the Northern Russia, especially the West Siberian fields in Tyumen. The main purpose of the total project III.0703, part 2 and this study is to evaluate the economic viability of seaborne export from this area to the European region, mainly with the use of a special ice-strengthened LPG vessel, constructed and designed for such seaborne operations. This study concentrates on both seaborne LPG transportation, the demand and supply for seaborne LPG in the world and marine transportation of LPG from the West Siberian fields. Another purpose is to see which regions are potential exporters, importers and buyers of seaborne export of LPG from Tyumen. Currently large quantities of liquefied gas are flared off at the West Siberian fields due to insufficient infrastructure, ...

CERN Document Server

We demonstrate that a massive asymptotic giant branch (AGB) star is a good candidate as the main source of short-lived radionuclides in the early solar system. Recent identification of massive (4-8 solar masses) AGB stars in the Galaxy, which are both lithium- and rubidium-rich, demonstrates that these stars experience proton captures at the base of the convective envelope (hot bottom burning), together with high-neutron density nucleosynthesis with 22Ne as a neutron source in the He shell and efficient dredge-up of the processed material. A model of a 6.5 solar masses star of solar metallicity can simultaneously match the abundances of 26Al, 41Ca, 60Fe, and 107Pd inferred to have been present in the solar nebula by using a dilution factor of 1 part of AGB material per 300 parts of original solar nebula material, and taking into account a time interval between injection of the short-lived nuclides and consolidation of the first meteorites equal to 0.53 Myr. Such a ...

CERN Document Server

We outline to the community the value of a Magellanic Clouds Survey that consists of three components: I) a complete-area, high resolution, multi-band UV-near-IR broadband survey; II) a narrowband survey in 7 key nebular filters to cover a statistically significant sample of representative HII regions and a large-area, contiguous survey of the diffuse, warm ISM; and III) a comprehensive FUV spectroscopic survey of 1300 early-type stars. The science areas enabled by such a dataset are as follows: A) assessment of massive star feedback in both HII regions and the diffuse, warm ISM; B) completion of a comprehensive study of the 30 Doradus giant extragalactic HII region (GEHR); C) development and quantitative parameterization of stellar clustering properties; D) extensive FUV studies of early-type stellar atmospheres and their energy distributions; and E) similarly extensive FUV absorption-line studies of molecular cloud structure and ISM extinction properties. These ...

Energy Technology Data Exchange (ETDEWEB)

The deep water parts of the Moere and Southern Voering Basins are large frontier areas, which are considered to contain significant undiscovered hydrocarbon resources, within Cretaceous and Paleogene reservoirs. PGS Reservoir AS have evaluated the Cretaceous and Paleogene successions of the shallow and deep water areas offshore Mid-Norway using high-resolution sequence stratigraphic techniques. The successions have been subdivided into about 20 stratigraphic sequences. The results are: (1) A more acurate and higher resolution stratigraphy, (2) Greater constraints on basin palaeoenvironmental and palaeogeographic reconstructions, (4) Fully integrated sandstone fairway models, with increased ability to reservoir and seal quality and continuity, (5) In addition to several obvious giant domal traps, subtler yet significant structural and stratigraphic leads and prospects can be identified, (6) The timing, volume and phase of hydrocarbon generation may be estimated more ...

Energy Technology Data Exchange (ETDEWEB)

More details about the construction of the Terra Nova floating production, storage and offloading (FPSO) vessel are provided. The vessel was built in the Daewoo shipyard in South Korea, and is now undergoing final fitting at Bull Arm, near St. John's, Newfoundland. When complete, the vessel will operate 350 km offshore, southeast of St. John's. It is 291 metres long and 45.5 metres wide and has a capacity of 960,000 barrels of oil. Although the FPSO will hold less than half of the last giant supertanker which sailed for Irving Oil, it has a crew of 81, four times the size of the supertanker, reflecting the technical uniqueness of the vessel and the intense pre-occupation with safety associated with the combination of winds, ice, waves, and shallow water around the Grand Banks. Also described is the alliance system of partnership between the oil companies and the main contractors. The deal stipulates that if the project ran over its budget, the oil ...

CERN Document Server

Simulations of planetary microlensing at high magnification that were carried out on a cluster computer are presented. It was found that the perturbations due to two-thirds of all planets occur in the time interval [-0.5t_FWHM, 0.5t_ FWHM] with respect to the peak of the microlensing light curve, where t_FWHM is typically about 14 hours. This implies that only this restricted portion of the light curve need be intensively monitored for planets, a very significant practical advantage. Nearly all planetary detections in high magnification events will not involve caustic crossings. The position angle, mass and projected orbital radius of a planet may be systematically determined from the planetary deviation. Earth mass planets may be detected with 1-m class telescopes if their projected orbital radii lie within about 1.5 - 2.5 AU. Giant planets are detectable over a much larger region. For multi-planet systems the perturbations due to individual planets can be ...

CERN Document Server

All of the solar system gas giants produce electron cyclotron masers, driven by the solar wind impinging on their magnetospheres. Extrapolating to the planet orbiting tau Boo, various authors have predicted that it may be within the detection limits of the 4-meter wavelength (74 MHz) system on the Very Large Array. This paper reports three epochs of observations of tau Boo. In no epoch do we detect the planet; various means of determining the upper limit to the emission yield single-epoch limits ranging from 135 to 300 mJy. We develop a likelihood method for multi-epoch observations and use it to constrain various radiation properties of the planet. Assuming that the planet does radiate at our observation wavelength, its typical luminosity must be less than about 10^{16} W, unless its radiation is highly beamed into a solid angle Omega << 1 sr. While within the range of luminosities predicted by various authors for this planet, this value is lower than recent ...

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 dynamics. The observed kinematics are well modeled ...

CERN Document Server

Current theories on planetary formation establish that giant planet formation should be contextual to their quick migration towards the central star due to the protoplanets-disc interactions on a timescale of the order of $10^5$ years, for objects of nearly 10 terrestrial masses. Such a timescale should be smaller by an order of magnitude than that of gas accretion onto the protoplanet during the hierarchical growing-up of protoplanets by collisions with other minor objects. These arguments have recently been analysed using N-body and/or fluid-dynamics codes or a mixing of them. In this work, inviscid 2D simulations are performed, using the SPH method, to study the migration of one protoplanet, to evaluate the effectiveness of the accretion disc in the protoplanet dragging towards the central star, as a function of the mass of the planet itself, of disc tangential kinematics and of the presence of a planet ``pseudo-atmosphere''. To this purpose, the SPH scheme is ...

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 massive star formation.

CERN Document Server

Delta Scorpii is a double giant Be star in the forefront of the Scorpio, well visible to the naked eye, being normally of magnitude 2.3. In the year 2000 its luminosity rose up suddenly to the magnitude 1.6, changing the usual aspect of the constellation of Scorpio. This phenomenon has been associated to the close periastron of the companion, orbiting on a elongate ellipse with a period of about 11 years. The periastron, on basis of high precision astrometry, is expected to occur in the first decade of July 2011, and the second star of the system is approaching the atmosphere of the primary, whose circumstellar disk has a H-alpha diameter of 5 milliarcsec, comparable with the periastron distance. The preliminary results of a photometric campaign, here presented in the very days of the periastron, show an irregular behavior of the star's luminosity, which can reflect some shocks between material around the two stars. The small luminosity increasement detected in the ...

International Nuclear Information System (INIS)

We have developed a new method for calculating common envelope (CE) events based on explicit consideration of the donor star's structural response to adiabatic mass loss. In contrast to existing CE prescriptions, which specify a priori the donor's remnant mass, we determine this quantity self-consistently and find that it depends on binary and CE parameters. This aspect of our model is particularly important to realistic modeling for upper main-sequence star donors without strongly degenerate cores (and hence without a clear core/envelope boundary). We illustrate the central features of our method by considering CE events involving 10 M_s_u_n donors on or before their red giant branch. For such donors, the remnant core mass can be as much as 30% larger than the star's He-core mass. Applied across a population of such binaries, our methodology results in a significantly broader remnant mass and final orbital separation distribution and a 20% increase in CE survival ...

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 ...

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 ...

International Nuclear Information System (INIS)

Over the recent years the nuclear structure around the N = 50 shell closure, which is very pronounced in the strontium and zirconium isotopes, has been the subject of extensive experimental and theoretical work. On the proton side Z = 38 and Z = 40 provide fairly closed sub-shells. In the strontium isotopes the lg/sub 9/2/ neutron shell is closed at "8"8Sr, supplying relatively pure neutron-hole and neutron-particle states with large spectroscopic factors in "8"7Sr and "8"9Sr, as well as core-coupled states. The mass region is thus ideally suited to examine the transition from a correlated to an uncorrelated (chaotic?) excitational behavior. These two types are characterized e.g. by the density of excited states, the transition strengths, and the spectroscopic factors observed in transfer reactions. We conducted (n,#gamma#) and (d,p) reactions leading to /sup 87,88,89/Sr in addition to "8"8Sr(d,t)"8"7Sr and 24 keV neutron capture in "8"8Sr. The vast amounts of data were used to analyze ...

International Nuclear Information System (INIS)

Iron is one of the main constituents of stainless steel which is used as a structural material in nuclear reactors. In fast and conceptual fusion and fusion-fission hybrid systems the primary energy range of neutron interaction lies between 1 and 20 MeV which opens up several reaction channels. The reaction cross-sections in this energy range are important for dosimetry, radiation damage, neutronics and safety studies of nuclear reactors. Keeping this in view Nuclear Data Section of the International Atomic Energy Agency has sponsored a Research Co-ordination Programme on Methods for the Calculation of Fast Neutron Nuclear Data for Structural Elements. Under this programme we propose to study (n,n'), (n,2n), (n,3n), (n,p), (n,np), (n,pn), (n,#alpha#), (n,n#alpha#), (n,#alpha#n) and (n,#gamma#) reaction cross-sections. Besides these, total, elastic and discrete level inelastic scattering cross-sections, angular distributions of neutron production cross-sections, neutron emission ...

International Nuclear Information System (INIS)

The mechanism of cobalt uptake was investigated using cells of the giant alga Chara corallina in which it is possible to resolve separately uptake by the cell wall and actual influx across the cell membrane. The absorption of "6"0Co by Chara cells appeared to saturate within 2 h. but this was mainly due to rapid uptake into the cell wall which accounted for 87-92% of the total activity. Even after prolonged desorption most of the cell-associated "6"0Co was found on the cell wall. The intracellular distribution of absorbed "6"0Co was investigated by fractionating the cell into cytoplasm and vacuole. It was shown that "6"0Co influx to the vacuole occurs simultaneously with influx to the cytoplasm. The transported species appears to be Co"2"+ rather than the less charged Co(OH)"+ or Co(O)_2. "6"0Co influx is pH dependent (optimum pH 7-9), and is sensitive to some other divalent metals. Influx from solutions containing 1 #mu#M "6"0Co was inhibited by 5 #mu#M Cd"2"+, ...

Energy Technology Data Exchange (ETDEWEB)

The Ordos Basin, the second largest sedimentary basin in China, contains the broad distribution of natural gas types. So far, several giant gas fields have been discovered in the Upper and Lower Paleozoic in this basin, each having over 1000x10{sup 8}m{sup 3} of proven gas reserves, and several gas pools have also been discovered in the Mesozoic. This paper collected the data of natural gases and elucidated the geochemical characteristics of gases from different reservoirs, and then discussed their origin. For hydrocarbons preserved in the Upper Paleozoic, the elevated {delta}{sup 13}C values of methane, ethane and propane indicate that the gases would be mainly coal-formed gases; the singular reversal in the stable carbon isotopes of gaseous alkanes suggests the mixed gases from humic sources with different maturity. In the Lower Paleozoic, the {delta} {sup 13}C{sub 1} values are mostly similar with those in the Upper Paleozoic, but the {delta}{sup 13}C{sub 2} and ...

International Nuclear Information System (INIS)

Numerical simulations show that box-shaped bulges of edge-on galaxies are not bulges: they are bars seen side-on. Therefore, the two components that are seen in edge-on Sb galaxies such as NGC 4565 are a disk and a bar. But face-on SBb galaxies always show a disk, a bar, and a (pseudo)bulge. Where is the (pseudo)bulge in NGC 4565? We use archival Hubble Space Telescope H-band images and Spitzer Space Telescope 3.6 #mu#m wavelength images, both calibrated to Two Micron All Sky Survey K_s band, to penetrate the prominent dust lane in NGC 4565. We find a high surface brightness, central stellar component that is clearly distinct from the boxy bar and from the disk. Its brightness profile is a Sersic function with index n = 1.55 #+-# 0.07 along the major axis and 1.33 #+-# 0.12 along the minor axis. Therefore, it is a pseudobulge. It is much less luminous than the boxy bar, so the true pseudobulge-to-total luminosity ratio of the galaxy is PB/T = 0.06 #+-# 0.01, much less than the ...

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 ...

Science.gov (United States)

1. Contest rules The European Space Agency (ESA) is launching a public competition to find the most suitable names for its four Cluster II space weather satellites. The quartet, which are currently known as flight models 5, 6, 7 and 8, are scheduled for launch from Baikonur Space Centre in Kazakhstan in June and July 2000. Professor Roger Bonnet, ESA Director of Science Programme, announced the competition for the first time to the European Delegations on the occasion of the Science Programme Committee (SPC) meeting held in Paris on 21-22 February 2000. The competition is open to people of all the ESA member states (*). Each entry should include a set of FOUR names (places, people, or things from history, mythology, or fiction, but NOT living persons). Contestants should also describe in a few sentences why their chosen names would be appropriate for the four Cluster II satellites. The winners will be those which are considered most suitable and relevant for the Cluster II mission. ...