Deviational simulation of phonon transport in graphene ribbons with ab initio scattering

We present a deviational Monte Carlo method for solving the Boltzmann-Peierls equation with ab initio 3-phonon scattering, for temporally and spatially dependent thermal transport problems in arbitrary geometries. Phonon dispersion relations and transition rates for graphene are obtained from density functional theory calculations. The ab initio scattering operator is simulated by an energy-conserving stochastic algorithm embedded within a deviational, low-variance Monte Carlo formulation. The deviational formulation ensures that simulations are computationally feasible for arbitrarily small temperature differences, while the stochastic treatment of the scattering operator is both efficient and exhibits no timestep error. The proposed method, in which geometry and phonon-boundary scattering are explicitly treated, is extensively validated by comparison to analytical results, previous numerical solutions and experiments. It is subsequently used to generate solutions for heat transport in graphene ribbons of various geometries and evaluate the validity of some common approximations found in the literature. Our results show that modeling transport in long ribbons of finite width using the homogeneous Boltzmann equation and approximating phonon-boundary scattering using an additional homogeneous scattering rate introduces an error on the order of 10% at room temperature, with the maximum deviation reaching 30% in the middle of the transition regime.Singapore-MIT Alliance for Research and TechnologyAmerican Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipNational Science Foundation (U.S.). Graduate Research Fellowshi

MRI radiomic features are independently associated with overall survival in soft tissue sarcoma

Purpose: Soft tissue sarcomas (STS) represent a heterogeneous group of diseases, and selection of individualized treatments remains a challenge. The goal of this study was to determine whether radiomic features extracted from magnetic resonance (MR) images are independently associated with overall survival (OS) in STS. Methods and Materials: This study analyzed 2 independent cohorts of adult patients with stage II-III STS treated at center 1 (N = 165) and center 2 (N = 61). Thirty radiomic features were extracted from pretreatment T1-weighted contrast-enhanced MR images. Prognostic models for OS were derived on the center 1 cohort and validated on the center 2 cohort. Clinical-only (C), radiomics-only (R), and clinical and radiomics (C+R) penalized Cox models were constructed. Model performance was assessed using Harrell\u27s concordance index. Results: In the R model, tumor volume (hazard ratio [HR], 1.5) and 4 texture features (HR, 1.1-1.5) were selected. In the C+R model, both age (HR, 1.4) and grade (HR, 1.7) were selected along with 5 radiomic features. The adjusted c-indices of the 3 models ranged from 0.68 (C) to 0.74 (C+R) in the derivation cohort and 0.68 (R) to 0.78 (C+R) in the validation cohort. The radiomic features were independently associated with OS in the validation cohort after accounting for age and grade (HR, 2.4; Conclusions: This study found that radiomic features extracted from MR images are independently associated with OS when accounting for age and tumor grade. The overall predictive performance of 3-year OS using a model based on clinical and radiomic features was replicated in an independent cohort. Optimal models using clinical and radiomic features could improve personalized selection of therapy in patients with STS

An objective frequency domain method for quantifying confined aquifer compressible storage using Earth and atmospheric tides

The groundwater hydraulic head response to the worldwide and ubiquitous atmospheric tide at 2 cycles per day (cpd) is a direct function of confined aquifer compressible storage. The ratio of the responses of hydraulic head to the atmospheric pressure change is a measure of aquifer barometric efficiency, from which formation compressibility and aquifer specific storage can be determined in situ rather than resorting to laboratory or aquifer pumping tests. The Earth tide also impacts the hydraulic head response at the same frequency, and a method is developed here to quantify and remove this interference. As a result, the barometric efficiency can be routinely calculated from 6-hourly hydraulic head, atmospheric pressure, and modeled Earth tide records where available for a minimum of 15 days duration. This new approach will be of critical importance in assessing worldwide problems of land subsidence or groundwater resource evaluation that both occur due to groundwater abstractio

Hopewell Newsletter- June 2010

1. Small Scale Geoarchaeological Investigations of Earthen Wall Construction at the Hopeton Earthworks (33RO 26) Several geoarchaeological and geophysical investigations have been conducted at the Hopeton Earthworks (33RO26) and met with good success (Figure 1). As such, soil cores excavated in the summer of 2007 were studied using a two-pronged methodology of soil profile characterization and magnetic susceptibility testing. These techniques were employed to closely examine three sections of earthen wall at different locations at Hopeton as a means of understanding the soil composition of the walls and assessing possible uniformity in wall construction across the site. The following focuses solely on the geoarchaeological study of the selected locations. 2. The Role of Geophysics at Hopewell Culture National Historical Park Hopewell Culture National Historical Park is best known for its earthwork complexes built by the Hopewell during the Middle Woodland period. The park was originally established in 1923 to preserve the Mound City site after its use as a World War I training camp. In the past two decades, the park has added four additional earthworks—Hopeton Earthworks, Hopewell Mound Group, Seip Earthworks, and High Bank Works—and recently had its boundaries increased to include Spruce Hill. The recent growth in land located within the park has provided opportunities for archaeological research, most of which used some sort of geophysical technique. 3. Recent Investigations at the Mound City Group Ohio Hopewell earthworks have been studied extensively, both in historic and in modern times. Mound excavations during historic and modern times have revealed much about the construction and use of mound space. More recent research at Hopewell sites in Ohio has focused on non-mound areas both within and adjacent to the earthworks. This article focuses on current research conducted outside of the enclosure at the Mound City Group. 4. Clues to the Relationship of the Riverbank Site (33RO1059) to other Ohio Hopewell Sites Through Instrumental Neutron Activation Analysis on Pottery Excavations were conducted at the Riverbank Site (33RO1059), located by the Hopewell Site (33RO27), in 2004 and 2006 to gather data from the site before it is eroded away by the Paint Creek and to improve understanding of the role of small sites located near large Hopewell earthworks. Instrumental Neutron Activation Analysis (INAA) was conducted on pottery from the Riverbank Site to help clarify its relationship with other nearby sites. Fifteen sherds from the site were sent to the University of Missouri Research Reactor (MURR) for INAA, and the results were compared to the larger database of Hopewell ceramics. Based on the results, which show that the fifteen sherds formed a unique trace element compositional group, the site likely represents a shortterm occupation, possibly for a pilgrimage to the Hopewell Site, and the ceramics were likely either locally constructed for use at the site or constructed elsewhere to carry items on the way to Hopewell. 5. Feature Finds from the Riverbank Site, 33RO1059 Located just south and east of the Hopewell site’s Square Enclosure by about 225 meters is the Riverbank site, 33RO1059, which represents multiple occupations spanning the Archaic through historic periods, and includes a significant Middle Woodland component. Particularly noteworthy are two impressive pit features that were encountered in 2006 during a data recovery project undertaken by the Midwest Archeological Center. These pits, Features 7 and 8, would have been contemporaneous with Hopewell activities at the nearby earthwork complex, and the material culture recovered from them provides an intriguing glimpse of activities outside of the earthwork walls. 6. The Initial Phase of the Magnetic Investigations of the Mound City Group (32RO 32) at the Hopewell Culture National Historical Park, Ross County, Ohio The Mound City Group (Site 32RO32) covers approximately 13 acres. It contained at least 23 mounds when Squier and Davis made the first study of the mound complex in 1846. In the summer of 2009, the Midwest Archeological Center conducted the initial phase of a magnetic survey of the entire site. The magnetic survey in the southern portion of the site covered 11,200 m2 or 2.77 acres. The magnetic data indicated the presence of numerous magnetic anomalies associated with the Hopewell occupation and with the World War I training facility of Camp Sherman

Who is to blame? The relationship between ingroup identification and relative deprivation is moderated by ingroup attributions

Contradictory evidence can be found in the literature about whether ingroup identification and perceived relative deprivation are positively or negatively related. Indeed, theoretical arguments can be made for both effects. It was proposed that the contradictory findings can be explained by considering a hitherto unstudied moderator: The extent to which deprivation is attributed to the ingroup. It was hypothesised that identification would only have a negative impact on deprivation, and that deprivation would only have a negative impact on identification, if ingroup attributions are high. To test this, attributions to the ingroup were experimentally manipulated among British student participants (N = 189) who were asked about their perceived deprivation vis-à-vis German students, yield ing support for the hypotheses

Rosa hybrid gene GAPC is mutated in the presence of the Rose Rosette Virus

Rose Rosette Disease (RRD) harms the global rose supply by modification of the growth and development in rose cultivar. RRD spreads via a negative-sense RNA plant virus transmitted by eriophyid mites. Importantly, there is no pre-existing knowledge about the biochemistry by which this virus debilitates roses. Here we implicate glyceraldehyde-3-phosphate dehydrogenase (GAPDH), one of the major metabolic enzymes in plants, as a possible target of the virus. Genomic DNA of the cytosolic form of the protein encoded by GAPC was extracted from both virally-infected and non-infected samples of the Rosa hybrid cultivar Rosa Tropicana. The sequence results provided several distinct differences in the GAPC gene of the non-infected rose compared to the virally-infected rose. Importantly, these modified nucleotide bases resulted in a putative protein sequence containing four unique non-conserved amino acid substitutions in the GAPDH enzyme. This study provides the first evidence of a gene impacted in virally-infected rose plants

Detection of Coronary Artery Disease on CT Chest Imaging

Overall aim: Improve diagnosis and management of CAD based on CT chest imaging. Improve diagnosis of silent CAD based on CT chest imaging: more patients who have findings of CAC on CT chest imaging will be diagnosed with CAD. Increase the number of appropriate statin prescriptions based on CAD findings on CT chest imaging