231 research outputs found
How Students Make Book Choices
In an effort to learn the extent and variety of factors that influence students\u27 book selection, the study reported here was undertaken. The researchers also questioned students regarding what they liked to read about, what authors they liked, and books they had recently read and enjoyed. A total of 688 fifth through eighth grade students enrolled in public schools in two small cities in Nebraska and California responded to a questionnaire. Numbers of respondents from both sexes were fairly evenly distributed across four grades
Results of Lung Cancer Screening in the Community.
PURPOSE: To address doubts regarding National Lung Screening Trial (NLST) generalizability, we analyzed over 6,000 lung cancer screenings (LCSs) within a community health system.
METHODS: Our LCS program included 10 sites, 7 hospitals (2 non-university tertiary care, 5 community) and 3 free-standing imaging centers. Primary care clinicians referred patients. Standard criteria determined eligibility. Dedicated radiologists interpreted all LCSs, assigning Lung Imaging Reporting and Data System (Lung-RADS) categories. All category 4 Lung-RADS scans underwent multidisciplinary review and management recommendations. Data was prospectively collected from November 2013 through December 2018 and retrospectively analyzed.
RESULTS: Of 4,666 referrals, 1,264 individuals were excluded or declined, and 3,402 individuals underwent initial LCS. Second through eighth LCSs were performed on 2,758 patients, for a total of 6,161 LCSs. Intervention rate after LCS was 14.6% (500 individuals) and was most often additional imaging. Invasive interventions (n = 226) were performed, including 141 diagnostic procedures and 85 surgeries in 176 individuals (procedure rate 6.6%). Ninety-five lung cancers were diagnosed: 84 non-small cell (stage 1: 60; stage 2: 7; stage 3: 9; stage 4: 8), and 11 small cell lung cancers. The procedural adverse event rate was 23/226 (10.1%) in 21 patients (0.6% of all screened individuals). Pneumothorax (n = 10) was the most frequent, 6 requiring pleural drainage. There were 2 deaths among 85 surgeries or 2.3% surgical mortality.
CONCLUSIONS: Our LCS experience in a community setting demonstrated lung cancer diagnosis, stage shift, intervention frequency, and adverse event rate similar to the NLST. This study confirms that LCS can be performed successfully, safely, and with equivalence to the NLST in a community health care setting
Spin relaxation in (110) and (001) InAs/GaSb superlattices
We report an enhancement of the electron spin relaxation time (T1) in a (110)
InAs/GaSb superlattice by more than an order of magnitude (25 times) relative
to the corresponding (001) structure. The spin dynamics were measured using
polarization sensitive pump probe techniques and a mid-infrared, subpicosecond
PPLN OPO. Longer T1 times in (110) superlattices are attributed to the
suppression of the native interface asymmetry and bulk inversion asymmetry
contributions to the precessional D'yakonov Perel spin relaxation process.
Calculations using a nonperturbative 14-band nanostructure model give good
agreement with experiment and indicate that possible structural inversion
asymmetry contributions to T1 associated with compositional mixing at the
superlattice interfaces may limit the observed spin lifetime in (110)
superlattices. Our findings have implications for potential spintronics
applications using InAs/GaSb heterostructures.Comment: 4 pages, 2 figure
The GenoChip: A New Tool for Genetic Anthropology
The Genographic Project is an international effort aimed at charting human migratory history. The project is nonprofit and nonmedical, and, through its Legacy Fund, supports locally led efforts to preserve indigenous and traditional cultures. Although the first phase of the project was focused on uniparentally inherited markers on the Y-chromosome and mitochondrial DNA (mtDNA), the current phase focuses on markers from across the entire genome to obtain a more complete understanding of human genetic variation. Although many commercial arrays exist for genome-wide single-nucleotide polymorphism (SNP) genotyping, they were designed for medical genetic studies and contain medically related markers that are inappropriate for global population genetic studies. GenoChip, the Genographic Project’s new genotyping array, was designed to resolve these issues and enable higher resolution research into outstanding questions in genetic anthropology. The GenoChip includes ancestry informative markers obtained for over 450 human populations, an ancient human (Saqqaq), and two archaic hominins (Neanderthal and Denisovan) and was designed to identify all known Y-chromosome and mtDNA haplogroups. The chip was carefully vetted to avoid inclusion of medically relevant markers. To demonstrate its capabilities, we compared the FST distributions of GenoChip SNPs to those of two commercial arrays. Although all arrays yielded similarly shaped (inverse J) FST distributions, the GenoChip autosomal and X-chromosomal distributions had the highest mean FST, attesting to its ability to discern subpopulations. The chip performances are illustrated in a principal component analysis for 14 worldwide populations. In summary, the GenoChip is a dedicated genotyping platform for genetic anthropology. With an unprecedented number of approximately 12,000 Y-chromosomal and approximately 3,300 mtDNA SNPs and over 130,000 autosomal and X-chromosomal SNPs without any known health, medical, or phenotypic relevance, the GenoChip is a useful tool for genetic anthropology and population genetics
The usability of recycled carbon fibres in short fibre thermoplastics: interfacial properties
The objective of this study was to investigate the feasibility of combining discontinuous recycled carbon fibres with polypropylene, to produce a low-cost, high specific stiffness material for high-volume applications. The inherent low affinity of carbon fibre and polypropylene motivated a detailed study of the surface characteristics of carbon fibre and interfacial behaviour between the two materials, using the microbond test. The effects of removing the sizing from the fibres, as well as introducing a maleic anhydride-grafted polypropylene coupling agent, were extensively investigated. Polypropylene was found to degrade when prepared under atmospheric conditions; therefore, it was necessary to form droplets under nitrogen. Removal of the sizing from the fibre using pyrolysis and solvolysis techniques altered the surface morphology of the fibre and increased the interfacial shear strength (IFSS) by 4 and 33 %, respectively. A more significant improvement in the fibre–matrix adhesion was achieved by adding a maleic anhydride coupling agent at 2 wt%, which increased the IFSS by 320 %
Using Polarized Spectroscopy to Investigate Order in Thin-Films of Ionic Self-Assembled Materials Based on Azo-Dyes
Three series of ionic self-assembled materials based on anionic azo-dyes and cationic benzalkonium surfactants were synthesized and thin films were prepared by spin-casting. These thin films appear isotropic when investigated with polarized optical microscopy, although they are highly anisotropic. Here, three series of homologous materials were studied to rationalize this observation. Investigating thin films of ordered molecular materials relies to a large extent on advanced experimental methods and large research infrastructure. A statement that in particular is true for thin films with nanoscopic order, where X-ray reflectometry, X-ray and neutron scattering, electron microscopy and atom force microscopy (AFM) has to be used to elucidate film morphology and the underlying molecular structure. Here, the thin films were investigated using AFM, optical microscopy and polarized absorption spectroscopy. It was shown that by using numerical method for treating the polarized absorption spectroscopy data, the molecular structure can be elucidated. Further, it was shown that polarized optical spectroscopy is a general tool that allows determination of the molecular order in thin films. Finally, it was found that full control of thermal history and rigorous control of the ionic self-assembly conditions are required to reproducibly make these materials of high nanoscopic order. Similarly, the conditions for spin-casting are shown to be determining for the overall thin film morphology, while molecular order is maintained
Genome-wide association study of post-traumatic stress disorder reexperiencing symptoms in >165,000 US veterans
Post-traumatic stress disorder (PTSD) is a major problem among military veterans and civilians alike, yet its pathophysiology remains poorly understood. We performed a genome-wide association study and bioinformatic analyses, which included 146,660 European Americans and 19,983 African Americans in the US Million Veteran Program, to identify genetic risk factors relevant to intrusive reexperiencing of trauma, which is the most characteristic symptom cluster of PTSD. In European Americans, eight distinct significant regions were identified. Three regions had values of P < 5 × 10−10: CAMKV; chromosome 17 closest to KANSL1, but within a large high linkage disequilibrium region that also includes CRHR1; and TCF4. Associations were enriched with respect to the transcriptomic profiles of striatal medium spiny neurons. No significant associations were observed in the African American cohort of the sample. Results in European Americans were replicated in the UK Biobank data. These results provide new insights into the biology of PTSD in a well-powered genome-wide association study
Genomic Ancestry of North Africans Supports Back-to-Africa Migrations
North African populations are distinct from sub-Saharan Africans based on cultural, linguistic, and phenotypic attributes; however, the time and the extent of genetic divergence between populations north and south of the Sahara remain poorly understood. Here, we interrogate the multilayered history of North Africa by characterizing the effect of hypothesized migrations from the Near East, Europe, and sub-Saharan Africa on current genetic diversity. We present dense, genome-wide SNP genotyping array data (730,000 sites) from seven North African populations, spanning from Egypt to Morocco, and one Spanish population. We identify a gradient of likely autochthonous Maghrebi ancestry that increases from east to west across northern Africa; this ancestry is likely derived from “back-to-Africa” gene flow more than 12,000 years ago (ya), prior to the Holocene. The indigenous North African ancestry is more frequent in populations with historical Berber ethnicity. In most North African populations we also see substantial shared ancestry with the Near East, and to a lesser extent sub-Saharan Africa and Europe. To estimate the time of migration from sub-Saharan populations into North Africa, we implement a maximum likelihood dating method based on the distribution of migrant tracts. In order to first identify migrant tracts, we assign local ancestry to haplotypes using a novel, principal component-based analysis of three ancestral populations. We estimate that a migration of western African origin into Morocco began about 40 generations ago (approximately 1,200 ya); a migration of individuals with Nilotic ancestry into Egypt occurred about 25 generations ago (approximately 750 ya). Our genomic data reveal an extraordinarily complex history of migrations, involving at least five ancestral populations, into North Africa
Emergency department spirometric volume and base deficit delineate risk for torso injury in stable patients
BACKGROUND: We sought to determine torso injury rates and sensitivities associated with fluid-positive abdominal ultrasound, metabolic acidosis (increased base deficit and lactate), and impaired pulmonary physiology (decreased spirometric volume and PaO(2)/FiO(2)). METHODS: Level I trauma center prospective pilot and post-pilot study (2000–2001) of stable patients. Increased base deficit was < 0.0 in ethanol-negative and ≤ -3.0 in ethanol-positive patients. Increased lactate was > 2.5 mmol/L in ethanol-negative and ≥ 3.0 mmol/L in ethanol-positive patients. Decreased PaO(2)/FiO(2 )was < 350 and decreased spirometric volume was < 1.8 L. RESULTS: Of 215 patients, 66 (30.7%) had a torso injury (abdominal/pelvic injury n = 35 and/or thoracic injury n = 43). Glasgow Coma Scale score was 14.8 ± 0.5 (13–15). Torso injury rates and sensitivities were: abdominal ultrasound negative and normal base deficit, lactate, PaO(2)/FiO(2), and spirometric volume – 0.0% & 0.0%; normal base deficit and normal spirometric volume – 4.2% & 4.5%; chest/abdominal soft tissue injury – 37.8% & 47.0%; increased lactate – 39.7% & 47.0%; increased base deficit – 41.3% & 75.8%; increased base deficit and/or decreased spirometric volume – 43.8% & 95.5%; decreased PaO(2)/FiO(2 )– 48.9% & 33.3%; positive abdominal ultrasound – 62.5% & 7.6%; decreased spirometric volume – 73.4% & 71.2%; increased base deficit and decreased spirometric volume – 82.9% & 51.5%. CONCLUSIONS: Trauma patients with normal base deficit and spirometric volume are unlikely to have a torso injury. Patients with increased base deficit or lactate, decreased spirometric volume, decreased PaO(2)/FiO(2), or positive FAST have substantial risk for torso injury. Increased base deficit and/or decreased spirometric volume are highly sensitive for torso injury. Base deficit and spirometric volume values are readily available and increase or decrease the suspicion for torso injury
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