232 research outputs found
Energy Localization in the Peyrard-Bishop DNA model
We study energy localization on the oscillator-chain proposed by Peyrard and
Bishop to model the DNA. We search numerically for conditions with initial
energy in a small subgroup of consecutive oscillators of a finite chain and
such that the oscillation amplitude is small outside this subgroup for a long
timescale. We use a localization criterion based on the information entropy and
we verify numerically that such localized excitations exist when the nonlinear
dynamics of the subgroup oscillates with a frequency inside the reactive band
of the linear chain. We predict a mimium value for the Morse parameter (the only parameter of our normalized model), in agreement with the
numerical calculations (an estimate for the biological value is ).
For supercritical masses, we use canonical perturbation theory to expand the
frequencies of the subgroup and we calculate an energy threshold in agreement
with the numerical calculations
Percepção sobre a importùncia da formação profissional por treinadores de judÎ de elite
This paper aims to report what is the importance elite judo coaches give to vocational training, in order to plain, prescript and control the training process. The paper is using a qualitative approach, and can be classified as a multiple case study. Eight judo coaches have been intentionally selected to take part of the research. Interviews have been performed with the coaches in two different moments: the first part was structured and the second part was semi structured. This study sample was composed by young coaches (37.4±3.8 years), who have already conquer expressive results in their carriers. They all have physical education degrees, while six of them are post-graduated (four specialists and two masters). We could observe that, for this group, the vocational training has always been of essential importance in their carriers as sportive coaches
Determination of surface lattice strain in ZnTe epilayers on {100}GaAs by ion channeling and reflectance spectroscopy
We report on the direct measurements of surface lattice strain in ZnTe epitaxial layers on {100}GaAs substrates by ion channeling Rutherford backscattering spectrometry and lowâtemperature (10 K) reflectance spectroscopy measurements. The measured ZnTe strain is the superposition of the expected thermal (tensile) strain and a thicknessâdependent residual compressive strain. Our data indicate that the removal of this residual strain is slower than the rate predicted by the equilibrium theory, following an apparent hâ1/2 powerâlaw dependence on the epilayer thickness h, above âŒ100 nm
Ground state of excitons and charged excitons in a quantum well
A variational calculation of the ground state of a neutral exciton and of
positively and negatively charged excitons (trions) in single quantum well is
presented. We study the dependance of the correlation energy and of the binding
energy on the well width and on the hole mass. Our results are are compared
with previous theoretical results and with avalaible experimental data.Comment: 8 pages, 5 figures presented to OECS
Prevalence and risk factors associated with cat parasites in Italy: a multicenter study
Background: Parasites that infect cats include protozoa, helminths and arthropods, many of which are transmissible to humans. Effective control relies on a good knowledge of parasite distribution and the risk factors for infection. The present study was aimed at evaluating the prevalence of major feline parasites in Italy and the risk factors associated with their occurrence. Methods: Over a 12-month study period, feces, hair and ectoparasites from naturally infected cats from feral colonies, shelters and private households were analyzed at 13 study centers across Italy. Samples from these cats (n = 987) were analyzed at all centers using the same diagnostic methods. Prevalence values and risk factors were evaluated statistically for the identification of predictors of risk. Results: The overall prevalence of gastro-intestinal and broncho-pulmonary (BP) nematodes was 35.9% (354/987). Toxocara cati was the most prevalent species (253/987; 25.6%), followed by Ancylostomatidae (98/987; 9.9%). Among BP nematodes, Aelurostrongylus abstrusus was the most common (76/987; 7.7%). Approximately 35.7% (352/987) of the study population was infested by ectoparasites, of which the most common were fleas (29.4%, 290/987), followed by ear mites Otodectes cynotis (9.8%, 97/987). Predictors of risk for parasite infection included age, a predominantly or exclusively outdoor lifestyle, geographic area and lack of antiparasitic treatment. Conclusions: Both ecto- and endoparasites are still common in cats throughout Italy, many of them being of zoonotic concern and vectors of pathogens to humans. Given the presence of parasites throughout the entire study period, year-round treatment should be considered. Furthermore, data confirm the need to protect the humanâanimal bond using proper endo- and ectoparasiticides to reduce the risk of human infection, in application of the One-Health concept
Typical Lung Carcinoids with Metastasis:Potential Role of MicroRNAs in the Regulation of Adaptive Immunity Associated with Disease: a Case Study
A Novel Pathway Regulates Thyroid Hormone Availability in Rat and Human Hypothalamic Neurosecretory Neurons
Hypothalamic neurosecretory systems are fundamental regulatory circuits influenced by thyroid hormone. Monocarboxylate-transporter-8 (MCT8)-mediated uptake of thyroid hormone followed by type 3 deiodinase (D3)-catalyzed inactivation represent limiting regulatory factors of neuronal T3 availability. In the present study we addressed the localization and subcellular distribution of D3 and MCT8 in neurosecretory neurons and addressed D3 function in their axons. Intense D3-immunoreactivity was observed in axon varicosities in the external zone of the rat median eminence and the neurohaemal zone of the human infundibulum containing axon terminals of hypophysiotropic parvocellular neurons. Immuno-electronmicroscopy localized D3 to dense-core vesicles in hypophysiotropic axon varicosities. N-STORM-superresolution-microscopy detected the active center containing C-terminus of D3 at the outer surface of these organelles. Double-labeling immunofluorescent confocal microscopy revealed that D3 is present in the majority of GnRH, CRH and GHRH axons but only in a minority of TRH axons, while absent from somatostatin-containing neurons. Bimolecular-Fluorescence-Complementation identified D3 homodimers, a prerequisite for D3 activity, in processes of GT1-7 cells. Furthermore, T3-inducible D3 catalytic activity was detected in the rat median eminence. Triple-labeling immunofluorescence and immuno-electronmicroscopy revealed the presence of MCT8 on the surface of the vast majority of all types of hypophysiotropic terminals. The presence of MCT8 was also demonstrated on the axon terminals in the neurohaemal zone of the human infundibulum. The unexpected role of hypophysiotropic axons in fine-tuned regulation of T3 availability in these cells via MCT8-mediated transport and D3-catalyzed inactivation may represent a novel regulatory core mechanism for metabolism, growth, stress and reproduction in rodents and humans
A construção da imagem de treinadores desportivos na internet: estudo de caso em um site de notĂcias esportivas
Objetivo: Verificar como Ă© construĂda a imagem dos treinadores desportivos, atravĂ©s da anĂĄlise de um site de notĂcias esportivas de grande acesso. Metodologia: Os dados foram obtidos a partir da coleta de todas as notĂcias relativas a treinadores, durante um mĂȘs (de 15 de agosto a 15 de setembro de 2011). As notĂcias foram classificadas por modalidade e a partir da leitura na Ăntegra das mesmas, foram elaboradas categorias que representassem o modo pelo qual essa mĂdia transmitia a imagem dos treinadores. De todas as notĂcias sobre esporte (total de 7894) foram selecionadas 1048 notĂcias alusivas a treinadores. Dessas, 987 eram relacionadas a treinadores de futebol masculino de grandes clubes e apenas 62 sobre treinadores de outras modalidades. Resultados: Os jornalistas da mĂdia analisada tĂȘm prioridade em produzir notĂcias que tratam os tĂ©cnicos desportivos como competentes ou incompetentes
Genetic susceptibility to Chagas disease cardiomyopathy: involvement of several genes of the innate immunity and chemokine-dependent migration pathways
Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study
: The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (pâ=â0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (pâ=â0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (pâ=â0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (pâ=â0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (pâ=â0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (pâ=â0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (pâ=â0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (pâ<â0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (pâ=â0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (pâ=â0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)
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