291 research outputs found
Fishtail projectile points from South America: the Brazilian record
The projectile points known as Fishtail or Fell represent a specific design associated with the earliesthunter-gatherers of the Pleistocene-Holocene transition in South America. Brazil was traditionallyconsidered as a marginal area of their distribution because in the past there were only asmall number of findings known, often inadequately documented. In this paper we present a generaland unified overview of the Brazilian record, including previously unpublished metric, technologicaland stylistic features. Also, we report on new findings of fishtail points in order to expandthe amount of information currently available. Some issues related to these records are alsoevaluated by comparing them with data from the Uruguayan plains and the Argentinean pampas.The general picture that emerges after this analysis shows a growing record of fishtail projectilepoints in southern Brazil, demonstrating a significant presence of these early paleo-South Americanpopulations.Fil: Loponte, Daniel Marcelo. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carbonera, M.. Regional Community University of Chapeco; BrasilFil: Sacur Silvestre, Romina. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentin
Study of second and third harmonic generation from an indium tin oxide nanolayer: Influence of nonlocal effects and hot electrons
We report comparative experimental and theoretical studies of the second and third harmonic generation from a 20 nm-thick indium tin oxide layer in proximity of the epsilon-near-zero condition. Using a tunable optical parametric amplifier, we record both spectral and angular dependence of the generated harmonic signals close to this particular point. In addition to the enhancement of the second harmonic efficiency close to the epsilon-near-zero wavelength, at oblique incidence, third harmonic generation displays an unusual behavior, predicted but not observed before. We implement a comprehensive, first-principles hydrodynamic approach able to simulate our experimental conditions. The model is unique, flexible, and able to capture all major physical mechanisms that drive the electrodynamic behavior of conductive oxide layers: nonlocal effects, which blueshift the epsilon-near-zero resonance by tens of nanometers; plasma frequency redshift due to variations of the effective mass of hot carriers; charge density distribution inside the layer, which determines the nonlinear surface and magnetic interactions; and the nonlinearity of the background medium triggered by bound electrons. We show that, by taking these contributions into account, our theoretical predictions are in very good qualitative and quantitative agreement with our experimental results. We expect that our results can be extended to other geometries where epsilon-near-zero nonlinearity plays an important role.Peer ReviewedPostprint (published version
Preservation of information in a prebiotic package model
The coexistence between different informational molecules has been the
preferred mode to circumvent the limitation posed by imperfect replication on
the amount of information stored by each of these molecules. Here we reexamine
a classic package model in which distinct information carriers or templates are
forced to coexist within vesicles, which in turn can proliferate freely through
binary division. The combined dynamics of vesicles and templates is described
by a multitype branching process which allows us to write equations for the
average number of the different types of vesicles as well as for their
extinction probabilities. The threshold phenomenon associated to the extinction
of the vesicle population is studied quantitatively using finite-size scaling
techniques. We conclude that the resultant coexistence is too frail in the
presence of parasites and so confinement of templates in vesicles without an
explicit mechanism of cooperation does not resolve the information crisis of
prebiotic evolution.Comment: 9 pages, 8 figures, accepted version, to be published in PR
Mechanical and environmental performance of asphalt concrete with high amounts of recycled concrete aggregates (RCA) for use in surface courses of pavements
Using aggregates from alternative sources has been considerably encouraged in recent decades. Reducing the consumption of natural aggregates from quarries (which have a substantial economic, visual, and environmental impact) is increasingly a concern. These needs have led to the broader use of more sustainable aggregates, increasing the incorporation percentages and extending their use to more demanding pavement layers (e.g., surface). In order to prove the efficiency of recycled concrete aggregates (RCAs) under such conditions, the “CirMat” project was developed. Among other works and tests, an asphalt concrete (AC) incorporating 52.3% RCA was characterized mechanically and environmentally. Empirical properties were evaluated, including the Marshall test (S = 20.2 kN; F = 2.9 mm) and resistance to permanent deformation (WTS = 0.10 mm/103 cycles), as well as a life cycle assessment (LCA), which confirmed that nine indicators were improved (from 1% to 93%). The test samples were taken from mixtures produced in the laboratory and at a plant (after which they were applied on a construction site). Comparing the results with those obtained in a reference AC (with natural aggregates), it was possible to conclude that the performance of the AC with RCAs was very similar. Therefore, the use of these aggregates, at high rates, does not represent additional risks for asphalt mixtures and has lower environmental impacts in most categories.This research was funded by the “Environment, Climate Change and Low Carbon Economy Programme—Environment Programme” (EEA financial mechanism 2014–2021) through the Funding Mechanism Commission established by Iceland, Liechtenstein, Norway, and Portugal, under the scope of project “CirMat—CIRcular aggregates for sustainable road and building MATerials” (Project 16 Call#2). This study was also supported by Fundação para a Ciência e a Tecnologia through the PhD grants number 2021.06428.BD and 2021.08004.BD. This work was also partly financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020, and under the Associate Laboratory Advanced Production and Intelligent Systems ARISE under reference LA/P/0112/2020
Outcomes of Transcutaneous Aortic Valve Replacement among high risk WV sample population.
Introduction:Transcatheter aortic valve replacement (TAVR) is a relatively new strategy for replacing the aortic valve. We elected to review our early experience to see if we could identify clinical characteristics at baseline or immediately following the procedure that would predict death within one year.
Methods:Charts for all patients assigned to receive TAVR procedure at St Mary’s medical center, Huntington, West Virginia between April, 2013 till November, 2016 were identified and reviewed. A total of seventy-two (72) cases were included.
Results: All cause mortality rate at index hospitalization, 30 days, and 12 months was 5.6%(N=4), 6.9%(N=5), 19.4%(N=14) respectively. Stroke rate at index hospitalization, 30 days, and 12 months was 2.8%(N=2), 2.8%(N=2), 8.3%(N=6) respectively. Major predictors of death were post procedure GFR, Contrast volume, and number of antiplatelet agents therapy (AUC= 0.638, 0.632, 0.637 respectively).
Conclusion: We found that post procedure GFR, less number of antiplatelet agents post procedure, and contrast volume may predict mortality within first 12 months post TAVR. Further studies focused on the above factors may be warranted
Baryon Structure and the Chiral Symmetry of QCD
Beyond the spontaneous chiral symmetry breaking scale light and strange
baryons should be considered as systems of three constituent quarks with an
effective confining interaction and a chiral interaction that is mediated by
the octet of Goldstone bosons (pseudoscalar mesons) between the constituent
quarks.Comment: Lecture given at the 35. Universit\"atswochen f\"ur Kern- und
Teilchenphysik, Schladming, Austria, March 1996 (Perturbative and
Nonperturbative Aspects of Quantum Field Theory, ed. by H. Latal and W.
Schweiger, Springer 1996). Paper (23 pages) with 2 figures and the required
macro lamuphy
Heart failure associated with imported malaria:a nationwide Danish cohort study
Abstract Aims Despite adequate treatment, recent studies have hypothesized that malaria may affect long‐term cardiovascular function. We aimed to investigate the long‐term risk of cardiovascular events and death in individuals with a history of imported malaria in Denmark. Methods Using nationwide Danish registries, we followed individuals with a history of malaria for the risk of incident heart failure (HF), myocardial infarction (MI), cardiovascular death and all‐cause death (1 January 1994 to 1 January 2017). The population was age‐ and sex‐matched with individuals without a history of malaria from the Danish population (ratio 1:9). We excluded patients with known HF and ischaemic heart disease at inclusion. Results We identified 3912 cases with a history of malaria (mean age 33 ± 17 years, 57% male, 41% Plasmodium falciparum infections). The median follow‐up was 9.8 years (interquartile range 3.9–16.4 years). Event rates per 1000 person‐years for individuals with a history vs. no history of malaria were HF: 1.84 vs. 1.32; MI: 1.28 vs. 1.30; cardiovascular death: 1.40 vs. 1.77; and all‐cause death: 5.04 vs. 5.28. In Cox proportional hazards models adjusted for cardiovascular risk factors, concomitant pharmacotherapy, region of origin, household income and educational level, malaria was associated with HF (HR: 1.59 [1.21–2.09], P = 0.001), but not MI (HR: 1.00 [0.72–1.39], P = 1.00), cardiovascular death (HR: 1.00 [0.74–1.35], P = 0.98) or all‐cause death (HR 1.11 [0.94–1.30], P = 0.21). Specifically, P. falciparum infection was associated with increased risk of HF (HR: 1.64 [1.14–2.36], P = 0.008). Conclusion Individuals with a history of imported malaria, specifically P. falciparum, may have an increased risk of incident HF
Outcomes of Transcutaneous Aortic Valve Replacement among high risk WV sample population
Introduction:Transcatheter aortic valve replacement (TAVR) is a relatively new strategy for replacing the aortic valve. We elected to review our early experience to see if we could identify clinical characteristics at baseline or immediately following the procedure that would predict death within one year.
Methods:Charts for all patients assigned to receive TAVR procedure at St Mary’s medical center, Huntington, West Virginia between April, 2013 till November, 2016 were identified and reviewed. A total of seventy-two (72) cases were included.
Results: All cause mortality rate at index hospitalization, 30 days, and 12 months was 5.6%(N=4), 6.9%(N=5), 19.4%(N=14) respectively. Stroke rate at index hospitalization, 30 days, and 12 months was 2.8%(N=2), 2.8%(N=2), 8.3%(N=6) respectively. Major predictors of death were post procedure GFR, Contrast volume, and number of antiplatelet agents therapy (AUC= 0.638, 0.632, 0.637 respectively).
Conclusion: We found that post procedure GFR, less number of antiplatelet agents post procedure, and contrast volume may predict mortality within first 12 months post TAVR. Further studies focused on the above factors may be warranted
Latent tuberculosis infection, tuberculin skin test and vitamin D status in contacts of tuberculosis patients: a cross-sectional and case-control study
<p>Abstract</p> <p>Background</p> <p>Deficient serum vitamin D levels have been associated with incidence of tuberculosis (TB), and latent tuberculosis infection (LTBI). However, to our knowledge, no studies on vitamin D status and tuberculin skin test (TST) conversion have been published to date. The aim of this study was to estimate the associations of serum 25-hydroxyvitamin D<sub>3 </sub>(25[OH]D) status with LTBI prevalence and TST conversion in contacts of active TB in Castellon (Spain).</p> <p>Methods</p> <p>The study was designed in two phases: cross-sectional and case-control. From November 2009 to October 2010, contacts of 42 TB patients (36 pulmonary, and 6 extra-pulmonary) were studied in order to screen for TB. LTBI and TST conversion cases were defined following TST, clinical, analytic and radiographic examinations. Serum 25(OH)D levels were measured by electrochemiluminescence immunoassay (ECLIA) on a COBAS<sup>® </sup>410 ROCHE<sup>® </sup>analyzer. Logistic regression models were used in the statistical analysis.</p> <p>Results</p> <p>The study comprised 202 people with a participation rate of 60.1%. Only 20.3% of the participants had a sufficient serum 25(OH)D (≥ 30 ng/ml) level. In the cross-sectional phase, 50 participants had LTBI and no association between LTBI status and serum 25(OH)D was found. After 2 months, 11 out of 93 negative LTBI participants, without primary prophylaxis, presented TST conversion with initial serum 25(OH)D levels: a:19.4% (7/36): < 20 ng/ml, b:12.5% (4/32):20-29 ng/ml, and c:0%(0/25) ≥ 30 ng/ml. A sufficient serum 25(OH)D level was a protector against TST conversion a: Odds Ratio (OR) = 1.00; b: OR = 0.49 (95% confidence interval (CI) 0.07-2.66); and c: OR = 0.10 (95% CI 0.00-0.76), trends p = 0.019, adjusted for high exposure and sputum acid-fast bacilli positive index cases. The mean of serum level 25(OH)D in TST conversion cases was lower than controls,17.5 ± 5.6 ng/ml versus 25.9 ± 13.7 ng/ml (p = 0.041).</p> <p>Conclusions</p> <p>The results suggest that sufficient serum 25(OH)D levels protect against TST conversion.</p
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