389 research outputs found
Preserving the Memory of those Perilous Times: Archaeology of a Civil War Prison in Blackshear, Georgia
In the closing months of 1864 Confederate prison authorities were forced to evacuate the large stockade prisoner of war (POW) camps at Millen and Andersonville, Georgia in the face of General Sherman’s ‘March to the Sea’. While attempting to evade Union forces, approximately 5,000 POWs were sent along the Atlantic and Gulf railroad in south east Georgia, stopping just outside of the town of Blackshear. For three weeks prisoners and guards camped along a small tributary of the Alabaha River with only a few steaks to mark a deadline between them. No formal prison enclosure or fortifications were constructed and while escapes were frequent the majority of the prisoners would endure their stay before continuing down the line to Thomasville. In this thesis, I continue the investigation of site 9PR26 by further delineating the boundaries with metal detection survey. By examining the artifact patterning I attempt to determine the general layout of the camp and why this particular location was chosen as the site of a makeshift prison by its commander
Initial Metabolic Profiles Are Associated with 7-Day Survival among Infants Born at 22-25 Weeks of Gestation.
OBJECTIVE:To evaluate the association between early metabolic profiles combined with infant characteristics and survival past 7 days of age in infants born at 22-25 weeks of gestation. STUDY DESIGN:This nested case-control consisted of 465 singleton live births in California from 2005 to 2011 at 22-25 weeks of gestation. All infants had newborn metabolic screening data available. Data included linked birth certificate and mother and infant hospital discharge records. Mortality was derived from linked death certificates and death discharge information. Each death within 7 days was matched to 4 surviving controls by gestational age and birth weight z score category, leaving 93 cases and 372 controls. The association between explanatory variables and 7-day survival was modeled via stepwise logistic regression. Infant characteristics, 42 metabolites, and 12 metabolite ratios were considered for model inclusion. Model performance was assessed via area under the curve. RESULTS:The final model included 1 characteristic and 11 metabolites. The model demonstrated a strong association between metabolic patterns and infant survival (area under the curve [AUC] 0.885, 95% CI 0.851-0.920). Furthermore, a model with just the selected metabolites performed better (AUC 0.879, 95% CI 0.841-0.916) than a model with multiple clinical characteristics (AUC 0.685, 95% CI 0.627-0.742). CONCLUSIONS:Use of metabolomics significantly strengthens the association with 7-day survival in infants born extremely premature. Physicians may be able to use metabolic profiles at birth to refine mortality risks and inform postnatal counseling for infants born at <26 weeks of gestation
Cosmic variance of the local Hubble flow in large-scale cosmological simulations
The increasing precision in the determination of the Hubble parameter has reached a per cent level at which large-scale cosmic flows induced by inhomogeneities of the matter distribution become non-negligible. Here, we use large-scale cosmological N-body simulations to study statistical properties of the local Hubble parameter as measured by local observers. We show that the distribution of the local Hubble parameter depends not only on the scale of inhomogeneities, but also on how one defines the positions of observers in the cosmic web and what reference frame is used. Observers located in random dark matter haloes measure on average lower expansion rates than those at random positions in space or in the centres of cosmic voids, and this effect is stronger from the halo rest frames compared to the cosmic microwave background (CMB) rest frame. We compare the predictions for the local Hubble parameter with observational constraints based on Type Ia supernova (SNIa) and CMB observations. Due to cosmic variance, for observers located in random haloes we show that the Hubble constant determined from nearby SNIa may differ from that measured from the CMB by ±0.8 per cent at 1σ statistical significance. This scatter is too small to significantly alleviate a recently claimed discrepancy between current measurements assuming a flat Λ cold dark matter (ΛCDM) model. However, for observers located in the centres of the largest voids permitted by the standard ΛCDM model, we find that Hubble constant measurements from SNIa would be biased high by 5 per cent, rendering this tension non-existent in this extreme case
The Atacama Cosmology Telescope: Two-Season ACTPol Spectra and Parameters
We present the temperature and polarization angular power spectra measured by
the Atacama Cosmology Telescope Polarimeter (ACTPol). We analyze night-time
data collected during 2013-14 using two detector arrays at 149 GHz, from 548
deg of sky on the celestial equator. We use these spectra, and the spectra
measured with the MBAC camera on ACT from 2008-10, in combination with Planck
and WMAP data to estimate cosmological parameters from the temperature,
polarization, and temperature-polarization cross-correlations. We find the new
ACTPol data to be consistent with the LCDM model. The ACTPol
temperature-polarization cross-spectrum now provides stronger constraints on
multiple parameters than the ACTPol temperature spectrum, including the baryon
density, the acoustic peak angular scale, and the derived Hubble constant.
Adding the new data to planck temperature data tightens the limits on damping
tail parameters, for example reducing the joint uncertainty on the number of
neutrino species and the primordial helium fraction by 20%.Comment: 23 pages, 25 figure
The Atacama Cosmology Telescope: Cosmological parameters from three seasons of data
We present constraints on cosmological and astrophysical parameters from
high-resolution microwave background maps at 148 GHz and 218 GHz made by the
Atacama Cosmology Telescope (ACT) in three seasons of observations from 2008 to
2010. A model of primary cosmological and secondary foreground parameters is
fit to the map power spectra and lensing deflection power spectrum, including
contributions from both the thermal Sunyaev-Zeldovich (tSZ) effect and the
kinematic Sunyaev-Zeldovich (kSZ) effect, Poisson and correlated anisotropy
from unresolved infrared sources, radio sources, and the correlation between
the tSZ effect and infrared sources. The power ell^2 C_ell/2pi of the thermal
SZ power spectrum at 148 GHz is measured to be 3.4 +\- 1.4 muK^2 at ell=3000,
while the corresponding amplitude of the kinematic SZ power spectrum has a 95%
confidence level upper limit of 8.6 muK^2. Combining ACT power spectra with the
WMAP 7-year temperature and polarization power spectra, we find excellent
consistency with the LCDM model. We constrain the number of effective
relativistic degrees of freedom in the early universe to be Neff=2.79 +\- 0.56,
in agreement with the canonical value of Neff=3.046 for three massless
neutrinos. We constrain the sum of the neutrino masses to be Sigma m_nu < 0.39
eV at 95% confidence when combining ACT and WMAP 7-year data with BAO and
Hubble constant measurements. We constrain the amount of primordial helium to
be Yp = 0.225 +\- 0.034, and measure no variation in the fine structure
constant alpha since recombination, with alpha/alpha0 = 1.004 +/- 0.005. We
also find no evidence for any running of the scalar spectral index, dns/dlnk =
-0.004 +\- 0.012.Comment: 26 pages, 22 figures. This paper is a companion to Das et al. (2013)
and Dunkley et al. (2013). Matches published JCAP versio
Interim heterogeneity changes measured using entropy texture features on T2- weighted MRI at 3.0 T predict pathological response to neoadjuvant chemotherapy in primary breast cancer
Objectives: This study investigated whether interim changes in hetereogeneity (measured using entropy features) on magnetic resonance images (MRI) were associated with pathological residual cancer burden (RCB) at final surgery in patients receiving neoadjuvant chemotherapy (NAC) for primary breast cancer.Methods: Institutional review board approval was waived for this retrospective study of 88 consenting women (age:30-79). Scanning was performed on a 3.0T MRI scanner prior to NAC (baseline) and after 2-3 cycles of treatment (interim). Entropy was derived from the grey-level co-occurrence matrix, on slice-matched baseline/interim T2- weighted images. Response, assessed using RCB score on surgically resected specimens, was compared statistically with entropy/heterogeneity changes and ROC analysis performed. Prediction of pCR within each tumour immunophenotype was evaluated.Results: Mean entropy percent differences between examinations, by response category, were: pCR:32.8%, RCB-I:10.5%, RCB-II:9.7% and RCB-III:3.0%. Prediction of ultimate pCR from coarse entropy changes between baseline/interim MRI across all lesions yielded 85.2% accuracy (area under ROC curve:0.845). Excellent sensitivity/specificity was obtained for pCR prediction within each immunophenotype: ER+: 100%/100%; HER2+: 83.3%/95.7%, TNBC: 87.5%/80.0%.Conclusions: Lesion T2 heterogeneity changes are associated with response to NAC using RCB scores, particularly for pCR, and can be useful in prediction across all immunophenotypes with good diagnostic accuracy
Evidence of lensing of the cosmic microwave background by dark matter halos
We present evidence of the gravitational lensing of the cosmic microwave background by 1013 solar
mass dark matter halos. Lensing convergence maps from the Atacama Cosmology Telescope Polarimeter
(ACTPol) are stacked at the positions of around 12 000 optically selected CMASS galaxies from the
SDSS-III/BOSS survey. The mean lensing signal is consistent with simulated dark matter halo profiles and
is favored over a null signal at 3.2σ significance. This result demonstrates the potential of microwave
background lensing to probe the dark matter distribution in galaxy group and galaxy cluster halos
Re-thinking the southern British oppida: networks, kingdoms and material culture
Copyright © 2010 SAGE Publications. Open access article.This article examines the role of a range of large settlements in late Iron Age and early Roman southern Britain (c. 100 BC–AD 70) conventionally described as oppida. After reviewing current perspectives on the function and chronology of British oppida, new insights are provided through the statistical analysis of assemblages of brooches and imported ceramics at a broad sample of sites. Analysis of material culture reveals distinct similarities and differences between several groups of sites, often transcending regional traditions and supposed tribal boundaries. This patterning is primarily explained by the emergence of new forms of political organization prior to Roman annexation, particularly the creation of the Southern and Eastern Kingdoms
Parental perception of neonatal intensive care in public sector hospitals in South Africa
Background. Little is known about parental experience and decision making with regard to premature infants requiring intensive care in developing countries. We undertook this study to characterise parents' experience of physician counselling and their role in making life-support decisions for very low-birth-weight (VLBW) (birth weight < 1 501 g) infants born in South Africa's public-sector neonatal intensive care units (NICUs).Methods. Parents of surviving VLBW infants treated in three Johannesburg-area public hospitals and attending follow-up clinics in August 2001 were interviewed regarding their experience of perinatal counselling on outcomes (pain, survival, disability), perception of actual and optimal decision making, and satisfaction with NICU communication.Results. Parents of 51 infants were interviewed. Seventy-five per cent of parents reported antenatal counselling by physicians on at least one perinatal topic (severe disability,pain, death, finances or religious/moral considerations). The majority of parents(> 60%) who received counselling thought that these topics had been discussed adequately. Most parents reported that doctors had the primary decisionmaking role, either without consulting them (41 %) or after consulting them (37%). Joint decision making was rare (14%). Parents wanted more input in life-support decisions than they reported being given.Conclusion. Counselling is not consistently provided in publicsector hospitals in Johannesburg. Parents of premature infants want a larger share in NICU decision making than they currently experience. Most parents were satisfied with communication later during their infant's hospitalisation. South Africa presents a unique opportunity to study the use of advanced medical technologies in a nation with marked disparities in access to care.
Core elements of exemplary academic integrity policy in Australian higher education
This paper reports on one important aspect of the preliminary findings from the Australian Learning and Teaching Council (ALTC) project, Academic integrity standards: Aligning policy and practice in Australian universities. Our project aims to identify approaches to the complex issues of academic integrity, and then to build on these approaches to develop exemplars for adaptation across the higher education sector. Based on analysis of publicly available online academic integrity policies at each of the 39 Australian universities, we have identified five core elements of exemplary academic integrity policy. These have been grouped under the headings, Access, Approach, Responsibility, Detail and Support, with no element given priority over another. In this paper we compare the five core elements identified in our research with best practice guidelines recommended by the Higher Education Academy (HEA) in the UK. We conclude that an exemplar policy needs to provide an upfront, consistent message, reiterated throughout the entire policy, which indicates a systemic and sustained commitment to the values of academic integrity and the practices that ensure it. Whereas the HEA created two discrete resources, the key aim and challenge of this project will be to develop exemplars that demonstrate a strong alignment between policy and practice
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