2,338 research outputs found
Astrophysics from data analysis of spherical gravitational wave detectors
The direct detection of gravitational waves will provide valuable
astrophysical information about many celestial objects. Also, it will be an
important test to general relativity and other theories of gravitation. The
gravitational wave detector SCHENBERG has recently undergone its first test
run. It is expected to have its first scientific run soon. In this work the
data analysis system of this spherical, resonant mass detector is tested
through the simulation of the detection of gravitational waves generated during
the inspiralling phase of a binary system. It is shown from the simulated data
that it is not necessary to have all six transducers operational in order to
determine the source's direction and the wave's amplitudes.Comment: 8 pages and 3 figure
George McClellan [1849-1913]: A Memoir read before the College of Physicians of Philadelphia, by J. Chalmers Da Costa, M.D., LL.D., Samuel D. Gross Professor of Surgery in Jefferson Medical College
A memoir of Dr. George McClellan (1849-1913). Dr. McClellan was the author of the book Regional Anatomy, and grandson of George McClellan, M.D.; the founder of Jefferson Medical College
Population expansion in the North African Late Pleistocene signalled by mitochondrial DNA haplogroup U6
Background
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The archaeology of North Africa remains enigmatic, with questions of population continuity versus discontinuity taking centre-stage. Debates have focused on population transitions between the bearers of the Middle Palaeolithic Aterian industry and the later Upper Palaeolithic populations of the Maghreb, as well as between the late Pleistocene and Holocene.
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Results
Improved resolution of the mitochondrial DNA (mtDNA) haplogroup U6 phylogeny, by the screening of 39 new complete sequences, has enabled us to infer a signal of moderate population expansion using Bayesian coalescent methods. To ascertain the time for this expansion, we applied both a mutation rate accounting for purifying selection and one with an internal calibration based on four approximate archaeological dates: the settlement of the Canary Islands, the settlement of Sardinia and its internal population re-expansion, and the split between haplogroups U5 and U6 around the time of the first modern human settlement of the Near East.
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Conclusions
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A Bayesian skyline plot placed the main expansion in the time frame of the Late Pleistocene, around 20 ka, and spatial smoothing techniques suggested that the most probable geographic region for this demographic event was to the west of North Africa. A comparison with U6's European sister clade, U5, revealed a stronger population expansion at around this time in Europe. Also in contrast with U5, a weak signal of a recent population expansion in the last 5,000 years was observed in North Africa, pointing to a moderate impact of the late Neolithic on the local population size of the southern Mediterranean coast
An analysis of the FIR/RADIO Continuum Correlation in the Small Magellanic Cloud
The local correlation between far-infrared (FIR) emission and radio-continuum
(RC) emission for the Small Magellanic Cloud (SMC) is investigated over scales
from 3 kpc to 0.01 kpc. Here, we report good FIR/RC correlation down to ~15 pc.
The reciprocal slope of the FIR/RC emission correlation (RC/FIR) in the SMC is
shown to be greatest in the most active star forming regions with a power law
slope of ~1.14 indicating that the RC emission increases faster than the FIR
emission. The slope of the other regions and the SMC are much flatter and in
the range of 0.63-0.85. The slopes tend to follow the thermal fractions of the
regions which range from 0.5 to 0.95. The thermal fraction of the RC emission
alone can provide the expected FIR/RC correlation. The results are consistent
with a common source for ultraviolet (UV) photons heating dust and Cosmic Ray
electrons (CRe-s) diffusing away from the star forming regions. Since the CRe-s
appear to escape the SMC so readily, the results here may not provide support
for coupling between the local gas density and the magnetic field intensity.Comment: 19 pages, 7 Figure
Seminal quality, testicle and epididymis morphology of bulls fed a diet containing gossypol
The objective was to evaluate the effect of intake of free gossypol on sperm quality and morphology of the testicles and epididymis of Nelore bulls. Twelve bulls were fed diets containing 3.3g of free gossypol/bull/day (cottonseed) (Group 1, n = 6) and a diet free of gossypol (Group 2, n = 6), respectively. Semen samples were collected in the beginning and end of the experiment which lasted 73 days. In the end of the study the testes and epididymis of bulls were removed to study the effect of free gossypol on histological characteristics. The average consumption of 3.3g of free gossypol/bull/day (mean 7.1mg of free gossypol/kg/day) reduced motility and sperm concentration and increased the percentage of major and total sperm defects, as well as the animals showing testes with seminiferous tubules of smaller thickness, fewer layers of spermatogenic lineage cells, smaller epididymal epithelium thickness and smaller number of sperm within the epididymal ducts, compared to animals with a diet free of gossypol (Group 2). The consumption of 3.3g of free gossypol/bull/day led to changes in morphology and morphometry of the testes and epididymis and reduced sperm quality of bulls.Objetivou-se avaliar o efeito da ingestão de gossipol livre sobre a qualidade espermática e a morfologia dos testículos e dos epidídimos de touros da raça Nelore. Doze touros receberam dieta contendo 3,3g de gossipol livre/touro/dia (caroço de algodão) (Grupo 1, n=6) e dieta isenta de gossipol (Grupo 2, n=6), respectivamente. Foram realizadas coletas de sêmen no início e no final do experimento, que teve duração de 73 dias. Ao final do estudo, foram retirados os testículos e os epidídimos dos touros para se estudar o efeito do gossipol livre sobre as características histológicas. O consumo médio de 3,3g de gossipol livre/touro/dia (média 7,1mg de gossipol livre/kg/dia) reduziu a motilidade e a concentração espermática e aumentou a porcentagem de defeitos espermáticos maiores e totais. Além disso, os animais apresentaram testículos com túbulos seminíferos de menor espessura de parede, menor número de camadas de células espermatogênicas, menor espessura do epitélio epididimário e menor número de espermatozoide no interior dos ductos epidídimários, em relação aos animais com dieta isenta de gossipol (Grupo 2). O consumo de 3,3g de gossipol livre/touro/dia acarretou alterações na morfologia e na morfometria dos testículos e dos epidídimos e reduziu a qualidade espermática dos touros.Universidade de Cuiabá Faculdade de Medicina VeterináriaUFMS Faculdade de Medicina Veterinária e ZootecniaEpamigUniversidade Federal do Mato GrossoUNIFESP-EPMUNIFESP, EPMSciEL
Daucus carota L. – An old model for cell reprogramming gains new importance through a novel expansion pattern of alternative oxidase (AOX) genes
The paper highlights Daucus carota L. as an ideal model to complement plant stress research on Arabidopsis thaliana L. Recently, alternative oxidase (AOX) is discussed as functional marker candidate for cell reprogramming upon stress. Carrot is the most studied species for cell reprogramming and our current research reveals that it is the only one that has expanded both AOX sub-family genes. We point to recently published, but not discussed results on conserved differences in the vicinity of the most active functional site of AOX1 and AOX2, which indicate the importance of studying AOX sequence polymorphism, structure and functionality. Thus, stress-inducible experimental systems of D. carota are especially appropriate to bring research on stress tolerance a significant step forward
Intraoperative imaging O-Arm™ in secondary surgical correction of post-traumatic orbital fractures
Abstract Purpose To determine the safety and efficacy of O-Arm™ intraoperative imaging in maxillofacial surgery of post-traumatic orbital fractures. In order to ensure correct placement of titanium plate, immediately after fixing, viewable, in the axial, sagittal and coronal images. Methods The authors evaluated 5 consecutive adult patients with orbital fractures who required a reoperation involving displacement of titanium mesh between January and December 2015. The displacement or incorrect positioning of titanium mesh was detected at post-operative CT scan or clinical neurological findings. Intraoperative O-Arm™ imaging was used for our patients who underwent secondary maxillofacial orbital fracture surgery due to the failure of first surgical approach. Results An eyelid incision was performed in order to obtain maximal exposure and minimizing cosmetic defects. Any previous fixation device was skeletonized and removed, any improperly reduced fracture was mobilized, reduced and refixated with 1.5 mm plates, screws and titanium mesh. The intra-operative O-Arm™ imaging technique was used at the end of the procedures. In 4 cases it confirmed the appropriateness of the newly obtained reconstruction, in 1 case a first scan showed a suboptimal result and the devices were correctly repositioned, guided by the O-Arm™ images. Conclusions Intraoperative O-Arm™ assisted craniofacial reconstruction surgery improves the assessment of neurovascular structure decompression, skeletal fragment identification, fixation procedures and for the correct re-establishment of facial symmetry in orbital floor fractures
Asymmetries between the production of D+ and D- mesons from 500 GeV/c pi- nucleon interactions as a function of xF and pt**2
We present asymmetries between the production of D+ and D- mesons in Fermilab
experiment E791 as a function of xF and pt**2. The data used here consist of
74,000 fully-reconstructed charmed mesons produced by a 500 GeV/c pi- beam on C
and Pt foils. The measurements are compared to results of models which predict
differences between the production of heavy-quark mesons that have a light
quark in common with the beam (leading particles) and those that do not
(non-leading particles). While the default models do not agree with our data,
we can reach agreement with one of them, PYTHIA, by making a limited number of
changes to parameters used
Mass Splitting and Production of and Measured in N Interactions
From a sample of decaying to the
final state, we have observed, in the hadroproduction experiment E791 at
Fermilab, and through
their decays to . The mass difference ) is measured to be ; for
, we find .
The rate of production from decays of the triplet is
(22\pm 2\pm 3) {%} of the total production assuming equal rate
of production from all three, as measured for and .
We do not observe a statistically significant baryon-antibaryon
production asymmetry. The and spectra of from
decays are observed to be similar to those for all 's
produced.Comment: 15 pages, uuencoded postscript 3 figures uuencoded, tar-compressed
fil
Interdisciplinary pedagogical activity, collaborative teaching under COVID-19
The Mundial Higher Education System is facing diverse and several challenges in a very short period of time. The pandemic situation of COVID-19 the world is facing imposed some really important changes in the Higher Education System: (i) The presence of a hybrid classes system (the online class combined with face-to-face classes); (ii) The acquisition of appropriate technologies and skills in order to use online platforms; (iii) The social distaimposed between students, teachers and between students and teachers; and (iv) the continuous teaching/learning process is complemented with the utilization of different tools of communications that support online classes.
In these circumstances, it is important to adopt innovative pedagogies that can better prepare students to ingress in the tourism profession, particularly in the context of the crisis that the tourism sector is facing. In order to bridge the gap between how different Tourism subjects can be taught in university and how Tourism Professional Teams Works in a real-life context under a pandemic situation, interdisciplinary pedagogical activities implemented within the classroom.
This article aims to describe and present interdisciplinary pedagogical practices within the Planning and Politics of Tourism and Introduction of EconoTourism classes, under a particular context, in order to develop important competencies that will allow students to be better prepared to work in the tourism sector. Specifically, the principal goal is to investigate the students’ perception of competencies acquired through interdisciplinary active under a collaborative learning activity within a pandemic situation.
This investigation adopted a case study method. In a quantitative approach, the students answered a questionnaire about self-assessment, motivatiskills, and competencies acquired along diff erent stages of collaborative teamwork between peers. Complementing these fi ndings, we used a qualitatapproach. We describe teacher’s and students´ cooperation, and coordination eff orts throughout the activity carried out along two diff erent disciplines
This research also provides important and novel insights to understand how students can develop important competencies, under a pandemic contexts learning from a hybrid process using interdisciplinary pedagogies. Teachers cooperation working through collaborative teaching activities and design considered as a proper interdisciplinary activity in order to graduate better students. The world is living a unique moment within a pandemic situation. Ait has a strong impact on the Higher Education System and all academic communities. In this sense, teachers must be open-minded regarding the learn process, as well as the use of new technologies.info:eu-repo/semantics/publishedVersio
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