417 research outputs found
The contribution of injury severity, executive and implicit functions to awareness of defi cits after traumatic brain injury (TBI)
Deficits in self-awareness are commonly seen after Traumatic Brain Injury (TBI) and adversely affect rehabilitative efforts, independence and quality of life (Ponsford, 2004). Awareness models predict that executive and implicit functions are important cognitive components of awareness though the putative relationship between implicit and awareness processes has not been subject to empirical investigation (Crosson et al., 1989; Ownsworth, Clare, & Morris, 2006; Toglia & Kirk, 2000). Severity of injury, also thought to be a crucial determinant of awareness outcome post-insult, is under-explored in awareness studies (Sherer, Boake, Levin, Silver, Ringholz, & Walter, 1998 ). The present study measured the contribution of injury severity, IQ, mood state, executive and implicit functions to awareness in head-injured patients assigned to moderate/severe head-injured groups using several awareness, executive, and implicit measures. Severe injuries resulted in greater impairments across most awareness, executive and implicit measures compared with moderate injuries, although deficits were still seen in the moderate group. Hierarchical regression results showed that severity of injury, IQ, mood state, executive and implicit functions made signifi cant unique contributions to selective aspects of awareness. Future models of awareness should account for both implicit and executive contributions
to awareness and the possibility that both are vulnerable to disruption after neuropathology. ( JINS , 2010, 16 , 1– 10 .
Evaluation of coalbed methane resource potential using limited data
Thesis (M.S.) University of Alaska Fairbanks, 2005This study presents the results of the evaluation of the Coalbed Methane (CBM) resource potential of the Cook Inlet Basin using a computer-aided well log analysis of the subsurface data. Coal seams were identified from the well logs. Formation and reservoir fluid properties including porosity, water saturation and net pay thickness of the coal seams were determined. The analysis revealed discontinuous coal seams interspaced largely by mudstone, silt, and sandstone formations within the depth of investigation. The CBM resource (Original Gas In Place) and recoverable reserves were estimated on per acre-foot basis. Monte Carlo simulation was run to refine the estimated CBM reserves and to allow for variations in the measured petrophysical input parameters used in the resource evaluation.Introduction -- Overview of the Cook Inlet Basin -- Formation evaluation and development of petrophysical property database -- Evaluation of resource potential -- Conclusions and recommendations -- Nomenclature -- References
Hydrocarbon Potential of the Upper Green River Petroleum System in the Uinta Basin, Utah: A Basin Modeling Approach
The Late Cretaceous Uinta Basin is a foreland basin located in northeastern Utah within the northern most portion of the Colorado Plateau. The basin's uplift and subsidence history and thermal evolution have impacted the maturity of source beds in the Parachute Creek Member. Sixty wells and three 2-D models generated from well logs are used in a basin modeling study of the Uinta Basin’s thermal structure, tectonic history, and petroleum system. These factors impact the maturation of source rocks within the Parachute Creek Member of the Green River Formation. All models were calibrated to measured data, including vitrinite reflectance and transformation ratios from Rock-Eval pyrolysis. The models predict that the heat flow ranges from 65 mW/m2 to 45 mW/m2 from south to north in the study area. Additionally, model calibration provides a means for estimating the amount of uplift and erosion in the Uinta Basin. For the three 2-D models, uplift and erosion predicted for the Uinta Basin ranges from 6700 ft to 7200 ft (2042 m to 2195 m). Based on the eroded thicknesses and heat flow values determined from calibration to measured thermal maturity indicators, the maturity of the rich oil shales of the Parachute Creek Member is inferred. Model predictions have suggested that source intervals of the Parachute Creek Member follow a general trend of increasing maturity from south to north in the study area. Local variations in predicted maturity that deviate from this trend most likely occur due to the effects of decreasing heat flow outpacing the effects of greater burial depths from south to north.Earth and Atmospheric Sciences, Department o
Electron microprobe investigations of metamorphic reactions and mineral growth histories, Kwoiek area, British Columbia
The Kwoiek Area of British Columbia contains a pendant or screen
of metamorphosed sedimentary and volcanic rocks almost entirely
surrounded by a portion of the Coast Range Batholith, and intruded by
several dozen stocks. The major metamorphic effects were produced by
the quartz diorite batholithic rocks, with minor and later effects by
the quartz diorite stocks. The sequence of important metamorphic
reactions in the metasedimentary and metavolcanic rocks, ranging in
grade from chlorite to sillimanite, is:
1. chlorite + carbonate + muscovite → epidote + biotite
2. chlorite + carbonate → actinolite + epidote
3. chlorite + muscovite → garnet + biotite
4. chlorite + epidote → garnet + hornblende
5. chlorite + muscovite → garnet + staurolite + biotite
6. chlorite + muscovite → aluminum silicate + biotite
7. muscovite + staurolite → garnet + aluminum silicate + biotite
8. staurolite → garnet + aluminum silicate
Continuous reactions, occurring between reactions 5 and 7, are:
A. chlorite + (high Ti) biotite + Al2O3 (from plagioclase?)→
garnet + staurolite + (low Ti) biotite + O2
B. muscovite (phengitic) → garnet + staurolite +muscovite (less
phengitic) + O2 (?)
Detailed electron microprobe work on garnet, staurolite, biotite,
and chlorite shows that:
(1) The garnet porphyroblasts are zoned according to a depletion
model, called the Rayleigh depletion model, which assumes equilibrium
between the edge of a growing garnet and the minerals which are
unzoned, notably biotite, chlorite, and muscovite, but which assumes
disequilibrium within the garnet.
(2) The staurolite porphyroblasts are also zoned, and from their
zoning patterns reactions A, B, and 5 are documented. Progressive
reduction of iron with increasing grade of metamorphism is also
inferred from the staurolite zoning patterns.
(3) During a late period of falling temperature garnet continued
to grow and the biotite and chlorite reequilibrated. The biotite,
chlorite, and garnet edge compositions can vary from point to point in
a given thin section, indicating that the volume of equilibrium at the
final stage of metamorphism was only a few cubic microns.
(4) The horizon within the garnet that grew at maximum temperature
can be identified. The Mg/Fe ratio of this horizon, if the garnet
composition is a limiting composition in the Al2O3 - K2O - FeO - MgO
tetrahedron, increases systematically with increasing metamorphic
grade. Biotite and chlorite compositions also show a general increase
in Mg/Fe ratio with increasing metamorphic grade, but staurolite
appears to show the reverse effect.
(5) The Mg/Fe ratio at the maximum temperature horizon of the
garnet porphyroblasts is a function of its Mn content as evidenced
from the study of five garnet-bearing rocks, collected from one outcrop
area, with the same assemblage but with differing proportions of
minerals.
An important implication of zoned minerals is that the effective
composition of a system in a phase lies on the join between
the homogeneous minerals (if there are two) and not within three-or-
four-phase fields when a zoned mineral, such as garnet or staurolite,
is present in the assemblage.
Study of the three aluminum silicates found in the Kwoiek Area
showed that a constant pressure change in polymorphs from andalusite
to kyanite to sillimanite took place with increasing temperature.
This transition series is best explained by the metastable formation
of andalusite.
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Inferring the Individual Psychopathologic Deficits With Structural Connectivity in a Longitudinal Cohort of Schizophrenia.
The prediction of schizophrenia-related psychopathologic deficits is exceedingly important in the fields of psychiatry and clinical practice. However, objective association of the brain structure alterations to the illness clinical symptoms is challenging. Although, schizophrenia has been characterized as a brain dysconnectivity syndrome, evidence accounting for neuroanatomical network alterations remain scarce. Moreover, the absence of generalized connectome biomarkers for the assessment of illness progression further perplexes the prediction of long-term symptom severity. In this paper, a combination of individualized prediction models with quantitative graph theoretical analysis was adopted, providing a comprehensive appreciation of the extent to which the brain network properties are affected over time in schizophrenia. Specifically, Connectome-based Prediction Models were employed on Structural Connectivity (SC) features, efficiently capturing individual network-related differences, while identifying the anatomical connectivity disturbances contributing to the prediction of psychopathological deficits. Our results demonstrated distinctions among widespread cortical circuits responsible for different domains of symptoms, indicating the complex neural mechanisms underlying schizophrenia. Furthermore, the generated models were able to significantly predict changes of symptoms using SC features at follow-up, while the preserved SC features suggested an association with improved positive and overall symptoms. Moreover, cross-sectional significant deficits were observed in network efficiency and a progressive aberration of global integration in patients compared to healthy controls, representing a group-consensus pathological map, while supporting the dysconnectivity hypothesis
Sequence Stratigraphy and Petrophysics of the late Ordovician Utica-Point Pleasant Interval in the Middle Appalachian Basin, Eastern Ohio and Western Pennsylvania
Approximately 400 well logs and two drill cores from eastern Ohio, western Pennsylvania, and northern West Virginia are used to construct a depositional model of the Utica Shale and associated Upper Ordovician strata. Previous studies of outcrop data from the Cincinnati arch and Jessamine dome recognized a number of Late Mohawkian to Early Cincinnatian third-order sequences deposited in an active foreland basin during onset of the Taconic orogeny. Sequences consist of deepening upward successions of transgressive limestone and shale, recording a period of sustained subsidence and rising sea-level along the eastern margin of North America. The transition from a carbonate-dominated system to a clastic-dominated system reflects the drowning of a widespread carbonate platform. The units of the Trenton Group and Lexington Limestone through Utica Shale comprise the transgressive systems tract (TST) of a large second-order sequence, composed of three, smaller scale third-order composite sequences. Third order sequences are regionally correlative, aggradational, and lack low-stand deposits. Sequences are separated by type 3 sequence boundaries that amalgamate with transgressive surfaces and separate the underlying highstand system tract (HST) from the overlying transgressive systems tract (TST). Chronostratigraphic surfaces demonstrate that basinal interbedded lime mudstone, shale, and marl facies of the Logana Shale and Point Pleasant Formations are contemporaneous and genetically related to platform limestone on the flanking Trenton and Lexington platforms. Average gamma-ray value contour maps of systems tracts and composite sequences indicate significant accumulation of carbonate sediment and build-up of the platforms during the Late Mohawkian, followed by increased clastic sedimentation and basin fill in the cross-strike Sebree trough and Point Pleasant sub-basin during the early Cincinnatian. Intervals with potentially high total organic carbon (TOC) content were identified using the Passey DeltaLogR method and a regression fit between bulk density and TOC, and compared to publicly available source rock data. The Logana through Point Pleasant intervals contain the highest amount of TOC in the area of the Point Pleasant sub-basin in eastern Ohio, with the Utica Shale containing marginal amounts of TOC in the Sebree trough and along the Trenton platform in northwestern Pennsylvania. Rock-eval geochemical data were used to map source potential and thermal maturity. The data shows southwest-northeast trending zones of maximum oil generation, a narrow liquids window, and a wide dry gas window. Maturity maps combined with porosity maps indicate a southwest-northeast trending prospective play fairway of the highest porosity and ideal thermally mature Point Pleasant reservoir, confined to eastern Ohio
Extragalactic chemical abundances: do HII regions and young stars tell the same story? The case of the spiral galaxy NGC 300
(Abridged) We have obtained new spectrophotometric data for 28 HII regions in
the spiral galaxy NGC 300, a member of the nearby Sculptor Group. The detection
of auroral lines, including [OIII]4363, [SIII]6312 and [NII]5755, has allowed
us to measure electron temperatures and direct chemical abundances for the
whole sample. We determine for the first time in this galaxy a radial gas-phase
oxygen abundance gradient based solely on auroral lines, and obtain the
following least-square solution: 12+log(O/H)=8.57-0.41 R/R25, where the
galactocentric distance is expressed in terms of the isophotal radius R25. The
gradient corresponds to -0.077 dex/kpc, and agrees very well with the
galactocentric trend in metallicity obtained for 29 B and A supergiants in the
same galaxy. The intercept of the regression for the nebular data virtually
coincides with the intercept obtained from the stellar data. This allows little
room for depletion of nebular oxygen onto dust grains, although in this kind of
comparison we are somewhat limited by systematic uncertainties, such as those
related to the atomic parameters used to derive the chemical compositions.
We discuss the implications of our result with regard to strong-line
abundance indicators commonly used to estimate the chemical compositions of
star-forming galaxies, such as R23. By applying a few popular calibrations of
these indices based on grids of photoionization models on the NGC 300 HII
region fluxes we find metallicities that are higher by 0.3 dex (a factor of
two) or more relative to our nebular (Te-based) and stellar ones.
We confirm a metallicity dependence of the `softness' parameter
eta=(O+/O++)/(S+/S++), in the sense that softer stellar continua are found at
high metallicity.Comment: Accepted for publication in The Astrophysical Journa
Inner forearc sequence architecture in response to climatic and tectonic forcing since 150 ka : Hawhe's Bay, New Zealand
International audienceThe influence of eustasy, tectonic deformation, and sediment flux as controlling parameters on basin stratigraphy and depositional sequence development are largely accepted. Eustasy is usually considered as the dominant mechanism of sequence generation, especially for Pleistocene successions. In active subduction-margin settings, the high rates of tectonic deformation are expected to have a stronger influence on basin-fill architecture, while sediment flux is generally less well constrained, and therefore less frequently considered. The active Hikurangi subduction margin in New Zealand offers the opportunity to quantitatively assess the relative roles of tectonic, climatic, and eustatic drivers. We present a quantitative source-to-sink-like study of the late Pleistocene succession from the Hawke's Bay sector of the inner forearc domain (c. 150 ka to present). The interpretation of a grid of high-resolution marine seismic data, onland and offshore core and well descriptions, and the integration of geomorphic studies enabled identification of system tracts. In turn these comprise two sea-level-cycle depositional sequences (LPS1 and LPS2), including one complete 100 ka sequence (LPS1). Isopach maps of both sequences reveal changes in sediment distribution and preservation that reflect the relative roles of tectonic deformation and eustasy. Eustasy dominates development of sequence architecture at relatively short time scales (i.e., 100 kyrs). Four long-lasting depocenters are identified over the inner forearc domain and located in four subsiding basins (Kidnappers, Mahia, Lachlan, and Motu-o-Kura basins). Significant shifts of the depocenter location in the basins are correlated with eustatic sea-level changes. Estimates of sediment volumes and masses from isopach maps indicate higher mass accumulation rates during climato-eustatic extremes, which we correlated to the onland erosional response. Sediment distribution and landscape evolution are strongly influenced by the interaction of the structural deformation and sediment flux. We present paleogeographic reconstructions for the inner forearc domain coincident with two paleoclimatic extremes (Last Glacial Maximum and Holocene Optimum). These illustrate the importance of eustatic changes, structural deformation, and sediment flux on the pattern of sediment distribution, accumulation, and sequence architecture
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