Detrital-zircon geochronology and provenance of the Ocloyic synorogenic clastic wedge, and Ordovician accretion of the Argentine Precordillera terrane

The Precordillera terrane in northwestern Argentina is interpreted to be anexotic (Laurentian) continental fragment that was accreted to western Gondwanaduring the Ordovician. One prominent manifestation of the subductionand collision process is a Middle?Upper Ordovician clastic wedge, which overliesa passive-margin carbonate-platform succession in the Precordillera. U/Pbages of detrital zircons from sandstones within the clastic wedge, as well as zirconsfrom clasts within conglomerates, provide documentation for the compositionof the sediment provenance. The ages of detrital zircons are consistentvertically through the succession, as well as laterally along and across strike ofthe Precordillera, indicating a single, persistent sediment source throughoutdeposition of the clastic wedge. The dominant mode (~1350?1000 Ma) of thedetrital-zircon ages corresponds to the ages of basement rocks in the WesternSierras Pampeanas along the eastern side of the Precordillera. A secondarymode (1500?1350 Ma) corresponds in age to the Granite-Rhyolite province ofLaurentia, an age range which is not known in ages of basement rocks of theWestern Sierras Pampeanas; however, detritus from Granite-Rhyolite-age rocksin the basement of the Precordillera was available through recycling of synriftand passive-margin cover strata. Igneous clasts in the conglomerates haveages (647?614 Ma) that correspond to the ages of minor synrift igneous rocks inthe nearby basement massifs; the same ages are represented in a minor mode(~750?570 Ma) of detrital-zircon ages. A quartzite clast in a conglomerate, aswell as parts of the population of detrital zircons, indicates the importanceof a source in the metasedimentary cover of the leading edge of the Precordillera.The Famatina continental-margin magmatic arc reflects pre-collisionsubduction of Precordillera lithosphere beneath the western Gondwana margin;however, no detrital zircons have ages that correspond to Famatina arcmagmatism, indicating that sedimentary detritus from the arc may have beentrapped in a forearc basin and did not reach the foreland. The indicators ofsedimentary provenance for the foreland deposits are consistent with subductionof the Precordillera beneath western Gondwana, imbrication of basementrocks from either the Precordillera or Gondwana into an accretionary complex,and recycling of deformed Precordillera cover rocks.Fil: Thomas, William A.. Geological Survey of Alabama; Estados UnidosFil: Astini, Ricardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Mueller, Paul A.. Florida State University; Estados UnidosFil: McClelland, William C.. University of Iowa; Estados Unido

Recovery of olfactory function after nine years of post-traumatic anosmia: a case report

<p>Abstract</p> <p>Introduction</p> <p>Olfactory loss due to head trauma is a common condition. Depending on the severity of the head trauma, anosmia might occur in up to 30% of patients. The period of time until recovery has been reported to be a couple of months in most cases. However, recovery from post-traumatic olfactory loss might occur much later. We present a rare case of recovery from anosmia nine years after the initial trauma.</p> <p>Case presentation</p> <p>We report the case of a 54-year-old Caucasian man who suffered complete anosmia from a severe car accident. Smell function as well as flavor perception during eating and drinking were also completely lost. After nine years, the patient had his first olfactory impressions, with his sense of smell gradually improving over a period of three years. We confirmed recovery of olfactory function using psychophysical and electrophysiological techniques.</p> <p>Conclusion</p> <p>In most cases, recovery of smell function occurs relatively soon after the head trauma and seems to rarely occur more than two years after the incident. However, patients should be informed that there is a small chance of recovery a long time after the trauma.</p

Fully covariant and conformal formulation of the Z4 system in a reference-metric approach: comparison with the BSSN formulation in spherical symmetry

We adopt a reference-metric approach to generalize a covariant and conformal version of the Z4 system of the Einstein equations. We refer to the resulting system as ``fully covariant and conformal", or fCCZ4 for short, since it is well suited for curvilinear as well as Cartesian coordinates. We implement this fCCZ4 formalism in spherical polar coordinates under the assumption of spherical symmetry using a partially-implicit Runge-Kutta (PIRK) method and show that our code can evolve both vacuum and non-vacuum spacetimes without encountering instabilities. Our method does not require regularization of the equations to handle coordinate singularities, nor does it depend on constraint-preserving outer boundary conditions, nor does it need any modifications of the equations for evolutions of black holes. We perform several tests and compare the performance of the fCCZ4 system, for different choices of certain free parameters, with that of BSSN. Confirming earlier results we find that, for an optimal choice of these parameters, and for neutron-star spacetimes, the violations of the Hamiltonian constraint can be between 1 and 3 orders of magnitude smaller in the fCCZ4 system than in the BSSN formulation. For black-hole spacetimes, on the other hand, any advantages of fCCZ4 over BSSN are less evident.Comment: 13 pages, 10 figure

ATLAS monitored drift tube chambers for super-LHC

After the high-luminosity upgrade of the Large Hadron Collider (LHC) at CERN, the ATLAS muon spectrometer is expected to work at 10 times increased background rates of gammas and neutrons. This is challenging as the momentum resolution of the spectrometer is expected to be 10 %. This requires a single tube resolution of the muon drift tubes of 80 mum. At background rates around 1000 Hz/cm2 space charge effects will lead in the slow and non-linear AR:CO2 = 93:7 gas mixture to a degradation of the drift-tube spatial resolution. This was studied before experimentally for gammas and low energetic neutrons. Almost no information exists for fast neutrons. Therefore, we organized our studies under the following aspects: - We investigated the influence of 11 MeV neutrons on the position resolution of ATLAS MDT chambers. At flux densities between 4 and 16 kHz/cm2, almost no influence on the position resolution was found, it degrades by only 10 mum at a detection efficiency of only 4*10-4. - We investigated inert gas mixtures on fastness and linearity of their position-drifttime (r-t) relation. At a reduction of the maximum drift time by a factor of 2, the use of the present hardware and electronics might be possible. For our experimental studies we used our Munich cosmic ray facility. Two gas mixtures show almost identical position resolution as the standard gas. - For spectrometer regions of highest background rates we contributed to the investigation of newly developed 15 mm drift tubes. Position resolutions have been measured as a function of gamma background rates between 0 and 1400 Hz/cm2. - Garfield simulations have been performed to simulate space charge effects due to gamma irradiation. Results will be presented for the standard geometry as well as for the new 15 mm drift tubes.Comment: 3 pages, 7 figures, conferenc

Physical Characterization of Warm Spitzer-observed Near-Earth Objects

Near-infrared spectroscopy of Near-Earth Objects (NEOs) connects diagnostic spectral features to specific surface mineralogies. The combination of spectroscopy with albedos and diameters derived from thermal infrared observations can increase the scientific return beyond that of the individual datasets. To that end, we have completed a spectroscopic observing campaign to complement the ExploreNEOs Warm Spitzer program that obtained albedos and diameters of nearly 600 NEOs (Trilling et al. 2010). Here we present the results of observations using the low-resolution prism mode (~0.7-2.5 microns) of the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). We also include near-infrared observations of ExploreNEOs targets from the MIT-UH-IRTF Joint Campaign for Spectral Reconnaissance. Our dataset includes near-infrared spectra of 187 ExploreNEOs targets (125 observations of 92 objects from our survey and 213 observations of 154 objects from the MIT survey). We identify a taxonomic class for each spectrum and use band parameter analysis to investigate the mineralogies for the S-, Q-, and V-complex objects. Our analysis suggests that for spectra that contain near-infrared data but lack the visible wavelength region, the Bus-DeMeo system misidentifies some S-types as Q-types. We find no correlation between spectral band parameters and ExploreNEOs albedos and diameters. We find slightly negative Band Area Ratio (BAR) correlations with phase angle for Eros and Ivar, but a positive BAR correlation with phase angle for Ganymed. We find evidence for spectral phase reddening for Eros, Ganymed, and Ivar. We identify the likely ordinary chondrite type analog for a subset of our sample. Our resulting proportions of H, L, and LL ordinary chondrites differ from those calculated for meteorite falls and in previous studies of ordinary chondrite-like NEOs.Comment: 6 Tables, 9 Figure

Social vs. practical problems in attaining a colonoscopy: Different patient profiles?

Background: Colonoscopy is an effective procedure for identifying precancerous polyps and cancerous lesions, but it is unlike other cancer screening tools in that it requires sedation and thus assistance from at least one other individual. The intent of this paper was to identify logistical problems in completing the colonoscopy and to examine their relationships with sociodemographic characteristics. Methods: All eligible patients (n = 2500) from two academic-affiliated colonoscopy centers (one free standing, one hospital-based) were invited to participate in an onsite, pre-colonoscopy survey; patients agreeing to participate (n = 1841, RR = 73.6%) received a $5.00 gift card. Multiple correspondence analysis (MCA) was used to identify the underlying dimensional structure of the problems. Bivariate statistics were performed to compare demographic variables and health literacy levels among patients reporting problems. Multivariate logistic regression with a backwards conditional solution was used to determine the demographic variables independently associated with problems. Results: Multiple correspondence analyses indicated two dimensions of problems (social and practical). Using logistic regression, social problems (e.g., finding someone to accompany the patient) were associated with not living in the same home as the driver, not working due to disability, and younger age. Practical problems (e.g., making an appointment) were associated with “other” minority race, poorer health, lower health literacy, and younger age. Conclusion: Patients experience different problems completing the colonoscopy based on socio-demographics. Particularly at risk are patients who find it difficult to navigate the system, are of younger age, or who may have smaller social networks

Macrophage-released ADAMTS1 promotes muscle stem cell activation.

Coordinated activation of muscle stem cells (known as satellite cells) is critical for postnatal muscle growth and regeneration. The muscle stem cell niche is central for regulating the activation state of satellite cells, but the specific extracellular signals that coordinate this regulation are poorly understood. Here we show that macrophages at sites of muscle injury induce activation of satellite cells via expression of Adamts1. Overexpression of Adamts1 in macrophages in vivo is sufficient to increase satellite cell activation and improve muscle regeneration in young mice. We demonstrate that NOTCH1 is a target of ADAMTS1 metalloproteinase activity, which reduces Notch signaling, leading to increased satellite cell activation. These results identify Adamts1 as a potent extracellular regulator of satellite cell activation and have significant implications for understanding the regulation of satellite cell activity and regeneration after muscle injury.Satellite cells are crucial for growth and regeneration of skeletal muscle. Here the authors show that in response to muscle injury, macrophages secrete Adamts1, which induces satellite cell activation by modulating Notch1 signaling