714 research outputs found
Room temperature mid-IR single photon spectral imaging
Spectral imaging and detection of mid-infrared (mid-IR) wavelengths are
emerging as an enabling technology of great technical and scientific interest;
primarily because important chemical compounds display unique and strong mid-IR
spectral fingerprints revealing valuable chemical information. While modern
Quantum cascade lasers have evolved as ideal coherent mid-IR excitation
sources, simple, low noise, room temperature detectors and imaging systems
still lag behind. We address this need presenting a novel, field-deployable,
upconversion system for sensitive, 2-D, mid-IR spectral imaging. Measured room
temperature dark noise is 0.2 photons/spatial element/second, which is a
billion times below the dark noise level of cryogenically cooled InSb cameras.
Single photon imaging and up to 200 x 100 spatial elements resolution is
obtained reaching record high continuous wave quantum efficiency of about 20 %
for polarized incoherent light at 3 \mum. The proposed method is relevant for
existing and new mid-IR applications like gas analysis and medical diagnostics
A surge of light at the birth of a supernova.
It is difficult to establish the properties of massive stars that explode as supernovae. The electromagnetic emission during the first minutes to hours after the emergence of the shock from the stellar surface conveys important information about the final evolution and structure of the exploding star. However, the unpredictable nature of supernova events hinders the detection of this brief initial phase. Here we report the serendipitous discovery of a newly born, normal type IIb supernova (SN 2016gkg), which reveals a rapid brightening at optical wavelengths of about 40 magnitudes per day. The very frequent sampling of the observations allowed us to study in detail the outermost structure of the progenitor of the supernova and the physics of the emergence of the shock. We develop hydrodynamical models of the explosion that naturally account for the complete evolution of the supernova over distinct phases regulated by different physical processes. This result suggests that it is appropriate to decouple the treatment of the shock propagation from the unknown mechanism that triggers the explosion
A review of the benefits and drawbacks to virtual field guides in today’s Geoscience higher education environment
Virtual Field Guides are a way for educators to tackle the growing issue of funding pressures in areas of higher education, such as geography. Virtual Field Guides are however underutilised and can offer students a different way of learning. Virtual Field Guides have many benefits to students, such as being more inclusive, building student skills and confidence in a controlled environment pre fieldtrip and can increase engagement in the topic studied. There are also benefits to the educator, such as reduced cost, more efficient students on fieldwork tasks and the ability to tailor and update their field guides to suit their needs. However there are drawbacks in the challenge of creation and their outcome as educational standalone tools. This paper reviews the literature around the benefits and draw backs to the creation and incorporation of virtual field guides in geoscience education. © 2017, The Author(s)
An inflamed necrotic appendix epiploicum with immediate contact to a non-inflamed appendix vermiformis: a case report
<p>Abstract</p> <p>Introduction</p> <p>Epiploic appendagitis is a rare cause of focal abdominal pain which, depending on its localisation, can mimic a variety of abdominal diseases. We describe a patient with an inflamed necrotic appendix epiploicum with immediate contact to a non-inflamed appendix vermiformis mimicking acute appendicitis. Considering the rare localization, this is the first report of this kind in the literature.</p> <p>Case presentation</p> <p>We present the case of a 50-year-old Caucasian man who presented with classic signs of acute appendicitis. On clinical exam, McBurney and Blumberg signs were positive. Additionally he had fever, leucocytosis (12/nl) and a slight increase in C-reactive protein (1 mg/dl). Based on the clinical presentation, the patient was taken to the operating room to perform an appendicectomy. Surprisingly, we found an inflamed necrotic appendix epiploicum, located immediately on a non-inflamed appendix vermiformis, which was ligated and excised.</p> <p>Conclusion</p> <p>This case report demonstrates that epiploic appendagitis can mimic acute appendicitis on clinical exam and should be considered in the broad spectrum of abdominal disease presenting with right lower quadrant pain.</p
Population genomics of marine zooplankton
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Bucklin, Ann et al. "Population Genomics of Marine Zooplankton." Population Genomics: Marine Organisms. Ed. Om P. Rajora and Marjorie Oleksiak. Springer, 2018. doi:10.1007/13836_2017_9.The exceptionally large population size and cosmopolitan biogeographic distribution that
distinguish many – but not all – marine zooplankton species generate similarly exceptional patterns of
population genetic and genomic diversity and structure. The phylogenetic diversity of zooplankton has
slowed the application of population genomic approaches, due to lack of genomic resources for closelyrelated
species and diversity of genomic architecture, including highly-replicated genomes of many
crustaceans. Use of numerous genomic markers, especially single nucleotide polymorphisms (SNPs), is
transforming our ability to analyze population genetics and connectivity of marine zooplankton, and
providing new understanding and different answers than earlier analyses, which typically used
mitochondrial DNA and microsatellite markers. Population genomic approaches have confirmed that,
despite high dispersal potential, many zooplankton species exhibit genetic structuring among geographic
populations, especially at large ocean-basin scales, and have revealed patterns and pathways of population
connectivity that do not always track ocean circulation. Genomic and transcriptomic resources are
critically needed to allow further examination of micro-evolution and local adaptation, including
identification of genes that show evidence of selection. These new tools will also enable further
examination of the significance of small-scale genetic heterogeneity of marine zooplankton, to
discriminate genetic “noise” in large and patchy populations from local adaptation to environmental
conditions and change.Support was provided by the
US National Science Foundation to AB and RJO (PLR-1044982) and to RJO (MCB-1613856); support to
IS and MC was provided by Nord University (Norway)
QCD and strongly coupled gauge theories : challenges and perspectives
We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe
Daily calcium intake in male children and adolescents obtained from the rapid assessment method and the 24-hour recall method
<p>Abstract</p> <p>Background</p> <p>In order to rapidly assess nutrient intake, Food Frequency Questionnaires (FFQ) have been developed and proven to be reliable for quick, user friendly analysis in adults. However, the accuracy of these questionnaires in children has been studied to a limited extent. The aim of this study was to compare the daily calcium intake values obtained from the Rapid Assessment Method (RAM), an FFQ, for assessing daily calcium intake in child and adolescent males with the values obtained from the 24-hour recall method.</p> <p>Methods</p> <p>Subjects included 162 child and adolescent males, aged 9–16 years, subdivided into elementary school (ES, 9–12 years) and high school (HS, 14–16 years) age groups.</p> <p>Results</p> <p>Daily calcium intake was significantly lower in ES compared with HS, using both methods. The intra-class correlation coefficients (ICC) between RAM values and those obtained using the 24-hour recall questionnaire were significant yet moderate (ICC = 0.46 and 0.43 for ES and HS, respectively). However, daily calcium intake obtained using RAM was significantly higher when compared with the 24-hour recall values in both ES (1576 +/- 1101 vs. 1003 +/- 543 mg, in RAM and 24-hour, respectively) and in HS males (1873 +/- 739 vs. 1159 +/- 515 mg, in RAM and 24-hour, respectively).</p> <p>Conclusion</p> <p>RAM overestimates daily calcium intake as compared with the 24-hour recall method in both child and adolescent males.</p
Short-term costs of conventional vs laparoscopic assisted surgery in patients with colorectal cancer (MRC CLASICC trial)
The short-term clinical results of the CLASICC trial indicated that clinical outcomes were similar between laparoscopic and open approaches. This study presents the short-term (3 month) cost analysis undertaken on a subset of patients entered into the CLASICC trial (682 of 794 patients). As expected the costs associated with the operation were higher in the 452 patients randomised to laparoscopic surgery (lap) compared with the 230 randomised to open procedure (open), £1703 vs £1386. This was partially offset by the other hospital (nontheatre) costs, which were lower in the lap group (£2930 vs £3176). The average cost to individuals for reoperations was higher in the lap group (£762 vs £553). Overall costs were slightly higher in the lap group (£6899 vs £6631), with mean difference of £268 (95%CI −689 to 1457). Sensitivity analysis made little difference to these results. The cost of rectal surgery was higher than for colon, for lap (£8259 vs £5586) and open procedures (£7820 vs £5503). The short-term cost analysis for the CLASICC trial indicates that the costs of either laparoscopic or open procedure were similar, lap surgery costing marginally more on average than open surgery
Field-study science classrooms as positive and enjoyable learning environments
We investigated differences between field-study classrooms and traditional science classrooms in terms of the learning environment and students’ attitudes to science, as well as the differential effectiveness of field-study classrooms for students differing in sex and English proficiency. A modified version of selected scales from the What Is Happening In this Class? questionnaire was used to assess the learning environment, whereas students’ attitudes were assessed with a shortened version of a scale from the Test of Science Related Attitudes. A sample of 765 grade 5 students from 17 schools responded to the learning environment and attitude scales in terms of both their traditional science classrooms and classrooms at a field-study centre in Florida. Large effect sizes supported the effectiveness of the field-studies classroom in terms of both the learning environment and student attitudes. Relative to the home school science class, the field-study class was considerably more effective for students with limited English proficiency than for native English speakers
Breast cancer risk prediction in women aged 35-50 years: impact of including sex hormone concentrations in the Gail model.
BACKGROUND: Models that accurately predict risk of breast cancer are needed to help younger women make decisions about when to begin screening. Premenopausal concentrations of circulating anti-Müllerian hormone (AMH), a biomarker of ovarian reserve, and testosterone have been positively associated with breast cancer risk in prospective studies. We assessed whether adding AMH and/or testosterone to the Gail model improves its prediction performance for women aged 35-50. METHODS: In a nested case-control study including ten prospective cohorts (1762 invasive cases/1890 matched controls) with pre-diagnostic serum/plasma samples, we estimated relative risks (RR) for the biomarkers and Gail risk factors using conditional logistic regression and random-effects meta-analysis. Absolute risk models were developed using these RR estimates, attributable risk fractions calculated using the distributions of the risk factors in the cases from the consortium, and population-based incidence and mortality rates. The area under the receiver operating characteristic curve (AUC) was used to compare the discriminatory accuracy of the models with and without biomarkers. RESULTS: The AUC for invasive breast cancer including only the Gail risk factor variables was 55.3 (95% CI 53.4, 57.1). The AUC increased moderately with the addition of AMH (AUC 57.6, 95% CI 55.7, 59.5), testosterone (AUC 56.2, 95% CI 54.4, 58.1), or both (AUC 58.1, 95% CI 56.2, 59.9). The largest AUC improvement (4.0) was among women without a family history of breast cancer. CONCLUSIONS: AMH and testosterone moderately increase the discriminatory accuracy of the Gail model among women aged 35-50. We observed the largest AUC increase for women without a family history of breast cancer, the group that would benefit most from improved risk prediction because early screening is already recommended for women with a family history
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