4,945 research outputs found
Human-specific CpG 'beacons' identify human-specific prefrontal cortex H3K4me3 chromatin peaks
Therefore, CpG-focused comparative sequence analysis can precisely pinpoint chromatin structures that contribute to the human-specific phenotype and further supports an integrated approach in genomic and epigenomic studie
Hydrothermal activity lowers trophic diversity in Antarctic sedimented hydrothermal vents
Sedimented hydrothermal vents are those in which hydrothermal fluid vents through sediment and are among the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermally active and off-vent areas of the Bransfield Strait (1050–1647 m depth). Microbial composition, biomass and fatty acid signatures varied widely between and within vent and non-vent sites and provided evidence of diverse metabolic activity. Several species showed diverse feeding strategies and occupied different trophic positions in vent and non-vent areas and stable isotope values of consumers were generally not consistent with feeding structure morphology. Niche area and the diversity of microbial fatty acids reflected trends in species diversity and was lowest at the most hydrothermally active site. Faunal utilisation of chemosynthetic activity was relatively limited but was detected at both vent and non-vent sites as evidenced by carbon and sulphur isotopic signatures, suggesting that the hydrothermal activity can affect trophodynamics over a much wider area than previously thought
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Tectonically controlled subglacial lakes on the flanks of the Gamburtsev Subglacial Mountains, East Antarctica
The morphology of surface lakes strongly influences their ecology and limnology (Wetzel, 2001). This morphology is a result of both the geologic processes that produce topographic basins and the regional climatic and local hydrologic processes that control water depth and sediment infilling (Carroll and Bohacs, 1999). Although basin forming processes range from glacial scour to meteorite impacts (Cohen, 2003), the deepest, oldest surface lakes are tectonically controlled (Meybeck, 1995) and contain diverse exotic ecosystems (Rossiterm and Kawanabe, 2000). Subglacial lakes are also thought to be ancient systems that may contain exotic biota (Bulat et al., 2004; Karl et al., 1999; Priscu et al., 1999). Here we present evidence for the scale and configuration of 2 large subglacial lakes in East Antarctica that together with Lake Vostok define a province of major lakes on the flanks of the Gamburtsev Subglacial Mountains. Spatially-defined in the new Moderate Resolution Imaging Spectroradiometer (MODIS) imagery of Antarctica (T. Scambos et al., A MODIS-based mosaic of Antarctica: MOA, submitted to Remote Sensing of Environment, 2005, hereinafter referred to as Scambos et al., submitted manuscript, 2005), these lakes are aligned parallel to Lake Vostok. Other data shows that they are distinguished by distinct gravity lows, flat ice surface slopes and have estimated water depths of at least 900 m. Surface elevation data indicates that large deep subglacial lakes have a profound influence on the regional ice sheet topography and probably ice sheet flow. These deep subglacial lakes with elongate, rectilinear morphology are tectonically controlled features. Unlike the shallow lakes in West Antarctica and beneath Dome Concordia, these deep subglacial lakes remained stable environments through many glacial cycles since their origin 10-35 Ma enabling the development of novel ecosystems
Spectroscopy of Giant Stars in the Pyxis Globular Cluster
The Pyxis globular cluster is a recently discovered globular cluster that
lies in the outer halo (R_{gc} ~ 40 kpc) of the Milky Way. Pyxis lies along one
of the proposed orbital planes of the Large Magellanic Cloud (LMC), and it has
been proposed to be a detached LMC globular cluster captured by the Milky Way.
We present the first measurement of the radial velocity of the Pyxis globular
cluster based on spectra of six Pyxis giant stars. The mean heliocentric radial
velocity is ~ 36 km/sec, and the corresponding velocity of Pyxis with respect
to a stationary observer at the position of the Sun is ~ -191 km/sec. This
radial velocity is a large enough fraction of the cluster's expected total
space velocity, assuming that it is bound to the Milky Way, that it allows
strict limits to be placed on the range of permissible transverse velocities
that Pyxis could have in the case that it still shares or nearly shares an
orbital pole with the LMC. We can rule out that Pyxis is on a near circular
orbit if it is Magellanic debris, but we cannot rule out an eccentric orbit
associated with the LMC. We have calculated the range of allowed proper motions
for the Pyxis globular cluster that result in the cluster having an orbital
pole within 15 degrees of the present orbital pole of the LMC and that are
consistent with our measured radial velocity, but verification of the tidal
capture hypothesis must await proper motion measurement from the Space
Interferometry Mission or HST. A spectroscopic metallicity estimate of [Fe/H] =
-1.4 +/- 0.1 is determined for Pyxis from several spectra of its brightest
giant; this is consistent with photometric determinations of the cluster
metallicity from isochrone fitting.Comment: 22 pages, 5 figures, aaspp4 style, accepted for publication in
October, 2000 issue of the PAS
A conventional surgical approach for removal of an ectopic tooth in the nasal cavity
A 40-year-old female patient presented to ears, nose and throat complaining of cacosmia and discharge from the left maxillary sinus. Her CT scan revealed an ectopic supplemental nasal tooth which could not be removed by nasoendoscopy. Therefore, a conventional intraoral surgical approach was taken. In this case, we discuss the indications for conventional surgical removal of teeth from the nasal cavity when a nasoendoscopic approach is not possible. We highlight the potential pitfalls of both conventional and nasoendoscopic approaches, including some essential considerations when treatment planning these cases
Anomaly mediated neutrino-photon interactions at finite baryon density
We propose new physical processes based on the axial vector anomaly and
described by the Wess-Zumino-Witten term that couples the photon, Z-boson, and
the omega-meson. The interaction takes the form of a pseudo-Chern-Simons term,
. This term
induces neutrino-photon interactions at finite baryon density via the coupling
of the Z-boson to neutrinos. These interactions may be detectable in various
laboratory and astrophysical arenas. The new interactions may account for the
MiniBooNE excess. They also produce a competitive contribution to neutron star
cooling at temperatures >10^9 K. These processes and related axion--photon
interactions at finite baryon density appear to be relevant in many
astrophysical regimes.Comment: 4 pages, 2 figures; references adde
Chronic Worry as Avoidance of Arousal
Previous research suggests that worry is primarily a verbal-linguistic activity that may serve as a method of cognitive avoidance of fearful imagery. The purpose of the present study was to examine cognitive avoidance in high worriers (N = 22) and low worriers (N = 24) using psychophysiological measures and a modified dichotic listening task. The task involved presenting neutral words into an unattending ear while worry or neutral scenarios were presented into the attending ear. Participants were given a surprise word recognition test of the words presented to provide evidence of cognitive avoidance beyond self-report. Contrary to the hypotheses, high worriers did not have less physiological reactivity than did low worriers. Low worriers recognized more words than did high worriers overall. High worriers remembered more words from the worry scenario than the neutral condition, as would be expected if they attempted to avoid the worry scenario. Implications for treatment of worry and the use of the dichotic listening task in researching worry are discussed
Chronic Worry as Avoidance of Arousal
Previous research suggests that worry is primarily a verbal-linguistic activity that may serve as a method of cognitive avoidance of fearful imagery. The purpose of the present study was to examine cognitive avoidance in high worriers (N = 22) and low worriers (N = 24) using psychophysiological measures and a modified dichotic listening task. The task involved presenting neutral words into an unattending ear while worry or neutral scenarios were presented into the attending ear. Participants were given a surprise word recognition test of the words presented to provide evidence of cognitive avoidance beyond self-report. Contrary to the hypotheses, high worriers did not have less physiological reactivity than did low worriers. Low worriers recognized more words than did high worriers overall. High worriers remembered more words from the worry scenario than the neutral condition, as would be expected if they attempted to avoid the worry scenario. Implications for treatment of worry and the use of the dichotic listening task in researching worry are discussed
Nickel thin films grown by pulsed laser deposition:influence of substrate and substrate temperature
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