1,090 research outputs found

    The Rise of the Industrial Rural Tenant Laborers and the Rise of the Industrial Economy: Historical Ethnography of the Heminitz Property ,Site (36LH267), Upper Macungie Township, Lehigh County,Pennsylvania

    Get PDF
    This paper presents the results of excavations at the Heminitz Property Site (36LH267), a rural domestic site in Upper Macungie Township, Lehigh County, Pennsylvania; Excavation, .\u27of several spatially and temporally discrete features and midden deposits in yards surrounding the house produced 6,875 artifacts. Documentary research revealed that the ca. 1843 house was intended to house tenant families engaged in agricultural labor. Analysis of the archaeological and documentary records associated with this site and the region shows that inthe mid-1800s, agricultural laborers possessed similar material. culture to neighboring independent farmers, while subsisting at a lower level of consumption. The transiiionfromagricultural to manufacturing labor occurred at the Heminitz Property Site in the mid-18/!Os, a time period\u27 that saw an increase in the quantity and value of domestic artifacts acquired by the site\u27s occupants. Archaeological and documentary data indicate that manufacturing laborers were materially betteT off than agricultural workers, though these benefits most likely came at the expense of chronic, low~l~erdebtto local storeowners. This investigation suggests the existence of a rural agrarian culture in\u27which individualsimd families could participate in differently, according to their particular economic circumstances

    Neutral Evolution as Diffusion in phenotype space: reproduction with mutation but without selection

    Full text link
    The process of `Evolutionary Diffusion', i.e. reproduction with local mutation but without selection in a biological population, resembles standard Diffusion in many ways. However, Evolutionary Diffusion allows the formation of local peaks with a characteristic width that undergo drift, even in the infinite population limit. We analytically calculate the mean peak width and the effective random walk step size, and obtain the distribution of the peak width which has a power law tail. We find that independent local mutations act as a diffusion of interacting particles with increased stepsize.Comment: 4 pages, 2 figures. Paper now representative of published articl

    Increased brain activation during working memory processing after pediatric mild traumatic brain injury (mTBI).

    Get PDF
    Purpose: The neural substrate of post-concussive symptoms following the initial injury period after mild traumatic brain injury (mTBI) in pediatric populations remains poorly elucidated. This study examined neuropsychological, behavioral, and brain functioning in adolescents post-mTBI to assess whether persistent differences were detectable up to a year post-injury. Methods: Nineteen adolescents (mean age 14.7 years) who experienced mTBI 3–12 months previously (mean 7.5 months) and 19 matched healthy controls (mean age 14.0 years) completed neuropsychological testing and an fMRI auditory-verbal N-back working memory task. Parents completed behavioral ratings. Results: No between-group differences were found for cognition, behavior, or N-back task performance, though the expected decreased accuracy and increased reaction time as task difficulty increased were apparent. However, the mTBI group showed significantly greater brain activation than controls during the most difficult working memory task condition. Conclusion: Greater working memory task-related activation was found in adolescents up to one year post-mTBI relative to controls, potentially indicating compensatory activation to support normal task performance. Differences in brain activation in the mTBI group so long after injury may indicate residual alterations in brain function much later than would be expected based on the typical pattern of natural recovery, which could have important clinical implications

    Decreased cerebral blood flow in chronic pediatric mild TBI: an MRI perfusion study

    Get PDF
    We evaluated cerebral blood flow (CBF) in chronic pediatric mild traumatic brain injury (mTBI) using arterial spin labeling (ASL) magnetic resonance imaging perfusion. mTBI patients showed lower CBF than controls in bilateral frontotemporal regions, with no between-group cognitive differences. Findings suggest ASL may be useful to assess functional abnormalities in pediatric mTBI

    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey : measuring DA and H at z = 0.57 from the baryon acoustic peak in the Data Release 9 spectroscopic Galaxy sample

    Get PDF
    We present measurements of the angular diameter distance to and Hubble parameter at z = 0.57 from the measurement of the baryon acoustic peak in the correlation of galaxies from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey. Our analysis is based on a sample from Data Release 9 of 264 283 galaxies over 3275 square degrees in the redshift range 0.43 < z < 0.70. We use two different methods to provide robust measurement of the acoustic peak position across and along the line of sight in order to measure the cosmological distance scale. We find DA(0.57) = 1408 ± 45 Mpc and H(0.57) = 92.9 ± 7.8 km s−1 Mpc−1 for our fiducial value of the sound horizon. These results from the anisotropic fitting are fully consistent with the analysis of the spherically averaged acoustic peak position presented in Anderson et al. Our distance measurements are a close match to the predictions of the standard cosmological model featuring a cosmological constant and zero spatial curvature.Publisher PDFPeer reviewe

    Exercise training reduces the acute physiological severity of post-menopausal hot flushes.

    Get PDF
    A hot-flush is characterised by feelings of intense heat, profuse elevations in cutaneous vasodilation and sweating, and reduced brain blood flow. Exercise training reduces self-reported hot-flush severity, but underpinning physiological data are lacking. We hypothesised that exercise training attenuates the changes in cutaneous vasodilation, sweat rate and cerebral blood flow during a hot flush. In a preference trial, 18 symptomatic post-menopausal women underwent a passive heat stress to induce hot-flushes at baseline and follow-up. Fourteen participants opted for a 16-week moderate intensity supervised exercise intervention, while 7 participants opted for control. Sweat rate, cutaneous vasodilation, blood pressure, heart rate and middle cerebral artery velocity (MCAv) were measured during the hot-flushes. Data were binned into eight equal segments, each representing 12.5% of hot flush duration. Weekly self-reported frequency and severity of hot flushes were also recorded at baseline and follow-up. Following training, mean hot-flush sweat rate decreased by 0.04 mg·cm2 ·min-1 at the chest (95% CI: 0.02-0.06, P = 0.01) and by 0.03 mg·cm2 ·min-1 (0.02-0.05, P = 0.03) at the forearm, compared with negligible changes in control. Training also mediated reductions in cutaneous vasodilation by 9% (6-12) at the chest and by 7% (4-9) at forearm (P≤0.05). Training attenuated hot flush MCAv by 3.4 cm/s (0.7-5.1, P = 0.04) compared with negligible changes in control. Exercise training reduced the self-reported severity of hot-flush by 109 arbitrary units (80-121, P<0.001). These data indicate that exercise training leads to parallel reductions in hot-flush severity and within-flush changes in cutaneous vasodilation, sweating and cerebral blood flo

    The Phoenix Mars Landing: An Initial Look

    Get PDF
    This presentation was part of the session : Ongoing and Proposed EDL Technology DevelopmentSixth International Planetary Probe WorkshopNASA's Phoenix Mars Lander will make a landing on Mars on May 25th, 2008. Following on from the overview of the Phoenix entry, descent and landing (EDL) system given at IPPW5, an initial look at the Phoenix landing will be presented, highlighting the salient, high level events that occurred during EDL. Initial EDL flight reconstruction results will be presented, along with a retelling of the flight operations events that occurred on approach to Mars, and during the landing event itself. Note: Given the short time duration between the Phoenix landing and IPPW6, only a presentation will be prepared for the workshop.NAS

    Role of microstructure and surface defects on the dissolution kinetics of CeO2, a UO2 fuel analogue.

    Get PDF
    The release of radionuclides from spent fuel in a geological disposal facility is controlled by the surface mediated dissolution of UO2 in groundwater. In this study we investigate the influence of reactive surface sites on the dissolution of a synthesised CeO2 analogue for UO2 fuel. Dissolution was performed on: CeO2 annealed at high temperature, which eliminated intrinsic surface defects (point defects and dislocations); CeO2-x annealed in inert and reducing atmospheres to induce oxygen vacancy defects; and on crushed CeO2 particles of different size fractions. BET surface area measurements were used as an indicator of reactive surface site concentration. Cerium stoichiometry, determined using X-ray Photoelectron Spectroscopy (XPS) and supported by X-ray Diffraction (XRD) analysis, was used to determine oxygen vacancy concentration. Upon dissolution in nitric acid medium at 90°C, a quantifiable relationship was established between the concentration of high energy surface sites and CeO2 dissolution rate; the greater the proportion of intrinsic defects and oxygen vacancies, the higher the dissolution rate. Dissolution of oxygen vacancy-containing CeO2-x gave rise to rates that were an order of magnitude greater than for CeO2 with fewer oxygen vacancies. While enhanced solubility of Ce3+ influenced the dissolution, it was shown that replacement of vacancy sites by oxygen significantly affected the dissolution mechanism due to changes in the lattice volume and strain upon dissolution and concurrent grain boundary decohesion. These results highlight the significant influence of defect sites and grain boundaries on the dissolution kinetics of UO2 fuel analogues and reduce uncertainty in the long-term performance of spent fuel in geological disposal
    • …
    corecore