255 research outputs found

    Determination of Force Corresponding to Maximal Lactate Steady State in Tethered Swimming

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    The main aim of the present investigation was to verify if the aerobic capacity (AC) measured in tethered swimming corresponds to the maximal lactate steady state (MLSS) and its correlation with 30 min and 400m free style swimming. Twenty-five swimmers were submitted to an incremental tethered swimming test (ITS) with an initial load of 20N and increments of 10N each 3min. After each stage of 3min, the athletes had 30s of interval to blood sample collections that were used to measure blood lactate concentrations ([La-]). The ACBI was determined by the abrupt increase in [La-] versus force (F). The points obtained between [La-] versus force (N) were adjusted by an exponential curve model to determine AC corresponding to 3.5mmol.l-1 (AC3.5) and 4.0mmol.l-1 (AC4.0). After these procedures, the swimmers performed maximal efforts of 30min and 400m in free style swimming. We used the distance performed in 30min and the time performed in 400m to calculate the median velocities (i.e. V30 and V400) of these protocols. After one week, in order to measure the MLSS, nine athletes performed three 30-min tethered swimming efforts with intensities of 90, 100, and 110% of ACBI. The ANOVA one-way was used to compare the ACBI, AC3.5 and AC4.0. Correlations between ACs, and between ACs and V30 and V400 (p\u3c0.05) were determined using the Pearson’s correlation coefficient. The intensity corresponding to 100% of ACBI was similar to the MLSS. It was observed significant correlations of the aerobic capacities (i.e. ACBI, AC3.5 and AC4.0) with V30 (r\u3e0.91) and V400 (r\u3e0.63). According to our results, it is possible to conclude that the ACBI corresponds to the MLSS, and both the AC - individually determined - and the AC - determined using fixed blood lactate concentrations of 3.5 and 4.0mmol.l-1 - can be used to predict the mean velocity of 30min and 400m in free style swimming. In addition to that, the tethered swimming system can be used for aerobic development in places where official sized swimming pools are not available, such as rehabilitation clinics and health clubs

    Shadows of charged rotating black holes: Kerr-Newman versus Kerr-Sen

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    Celebrating the centennial of its first experimental test, the theory of General Relativity (GR) has successfully and consistently passed all subsequent tests with flying colours. It is expected, however, that at certain scales new physics, in particular in the form of quantum corrections, will emerge, changing some of the predictions of GR, which is a classical theory. In this respect, black holes (BHs) are natural configurations to explore the quantum effects on strong gravitational fields. BH solutions in the low-energy effective field theory description of the heterotic string theory, which is one of the leading candidates to describe quantum gravity, have been the focus of many studies in the last three decades. The recent interest in strong gravitational lensing by BHs, in the wake of the Event Horizon Telescope observations, suggests comparing the BH lensing in both GR and heterotic string theory, in order to assess the phenomenological differences between these models. In this work, we investigate the differences in the shadows of two charged BH solutions with rotation: one arising in the context of GR, namely the Kerr-Newman solution, and the other within the context of low-energy heterotic string theory, the Kerr-Sen solution. We show and interpret, in particular, that the stringy BH always has a larger shadow, for the same physical parameters and observation conditions.Comment: 11 pages, 11 figures, Contribution to Selected Papers of the Fifth Amazonian Symposium on Physics, v2: references added, typos corrected, matches published versio

    From handcrafting to a certified and ergonomic collaborative workstation: the digital transformation process

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    As manufacturing enters an era of mass customization, new technological solutions with more versatility and flexibility are brought to the industry. Collaborative robots, or COBOTs, can now safely work near humans, a key advantage that enables highly-flexible production and opens the possibility to tackle the incidence of occupational health problems. Although the advantages of collaborative robotic manufacturing have been extensively praised, adapting a manual production workstation to integrate robotic technology is far from being a linear and easy process. In this work, we explore this delicate balance between the ergonomic, production, and safety requirements in the design of a new collaborative cell. We explain the different steps of this digital transformation process and the thought process behind human-robot task allocation to maximize the collaborative robot efficiency while improving the work conditions. This work describes the development of a certified and production-ready collaborative workstation based on ergonomic criteria. Results show a significant reduction in the global ergonomic risk score associated with the workers' actions and postures and an increase in production quotas, compared to the previous manual process.This work was supported by NORTE-06-3559-FSE-000018, integrated into the invitation NORTE-59-2018-41, aiming to hire highly-qualified human resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund (ESF)

    (R)-(1-Ammonio­eth­yl)phospho­nate

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    The title compound, C2H8NO3P, crystallizes in its zwitterionic form H3N+CH(CH3)PO(O−)(OH). In the crystal, the molecules are linked by N—H⋯O and O—H⋯O hydrogen bonds

    Physical and morphological characterization of reactively magnetron sputtered TiN films

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    The present paper reports the influence of growth conditions on the properties of TiN thin films deposited by rf reactive magnetron sputtering in the low-pressure range. The effects of rf power at the Ti target and the negative bias voltage at the substrate in the morphology, structure, electrical resistivity and colour of the samples were studied in detail. X-Ray diffraction results showed that the delta-TiN phase (a(0) similar to 0.430 nm) is detected in all the samples. The sample prepared with grounded substrate revealed a lattice parameter close to the bulk value (0.424 nm), which is a consequence of a low stress state, due to the absence of ion bombardment. The sample deposited at 1000 W has a lattice parameter of 0.426 nm, close to that of the stress-free material (a(0) =0.424 nm), probably due to some stress relief. All films have a columnar-type structure, lying in the T and I zone of the Thornton Model. The resistivity of the TiN films is almost constant and close to 60 muOmega cm independently of the preparation conditions, except for the films deposited at 1000 W, p similar to 215 muOmega cm, and for the grounded sample, p similar to 153 muOmega cm. These values are probably due to cracks associated with stress relieves, in the first case, and the lack of ion bombardment that leads to films with lower density and higher number of defects in the second. No significant variations in colour were observed

    Safety requirements for the design of collaborative robotic workstations in europe – a review

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    Industrial manufacturing is moving towards flexible and intelligent processes. Human-Robot Collaboration (HRC) has a pivotal role in smart factories due to a more versatile resource allocation that ultimately drives higher productivity and efficiency. The physical barriers that separate robots’ and humans’ workspaces are removed to facilitate HRC, which raises new safety concerns. To cope with this new robotics paradigm, regulatory legislation and international safety standards have been issued and are enforced for any machinery placed in factories. In this paper, we aim to shorten the gap between research projects and industry-ready robotic systems, by providing the guidelines and general requirements for collaborative robotic applications. We review the current international safety standards, certification procedures under the scope of European jurisdiction, and elaborate a literature review of papers related to safety for collaborative workstations.This work was supported by NORTE-06-3559-FSE-000018, integrated into the invitation NORTE-59-2018-41, aiming to hire highly-qualified human resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund (ESF)

    Estimating dispersal and gene flow in the neotropical freshwater turtle Hydromedusa maximiliani (Chelidae) by combining ecological and genetic methods

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    Hydromedusa maximiliani is a vulnerable neotropical freshwater turtle endemic to mountainous regions of the Atlantic rainforest in southeastern Brazil. Random amplified polymorphic DNA (RAPD) was used to estimate the gene flow and dispersal for individuals inhabiting rivers and streams within a drainage. Nine primers generated 27 scoreable bands, of which 9 (33%) were polymorphic and produced 12 RAPD phenotypes. The gene flow estimates (Nm) among turtles inhabiting different rivers and streams were variable, ranging from 0.09 to 3.00 (mean: 0.60). For some loci, the rates of gene flow could offset population differentiation (Nm > 1), whereas for others random genetic drift could result in population divergence (Nm < 1). Since the genetic variation of this turtle seems to be structured according to the natural hierarchical system of rivers and streams within drainages, management programs involving translocations between different regions across the geographical range of H. maximiliani should be viewed with caution.151155Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Dissecção da Axila no Tratamento do Câncer de Mama

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    A dissecção da axila no tratamento do câncer da mama tem sido questionada quanto aos seus objetivos. No passado próximo a intenção era curativa: presentemente tem sido indicada principalmente para oferecer informação de extensão da doença (comprometimento de linfonodos por tumor) e tratamentos complementares, principalmente a quimioterapia adjuvante. Apenas alguns subgrupos de mulheres têm-se beneficiado realmente da quimioterapia adjuvante: as pré-meno-pausadas com linfonodos axilares comprometidos com tumor. Uma vez decidida a dissecção axilar, ainda resta a questão de saber se deve ser radical, ou limitada a níveis I e II (até músculo peitoral menor). Muitos centros importantes de câncer indicam a dissecção limitada da axila, que em média retira cerca de 10 linfonodos, alegando que desta forma não há risco de edema importante do braço e conseguem boa informação prognóstica e bom controle tumoral da axila. Aqueles que indicam a dissecção radical alegam que esta é a única forma de se obter informação real da situação axilar. Algumas pacientes podem ter linfonodos livres de tumor na parte baixa da axila, mas com tumor no ápice axilar ("skip metastasis") e a única forma de descobri-lo seria através da dissecção radical. Como a dissecção radical da axila pode causar edema do braço, é importante questionara real indicação da mesma. Pacientes em pós-menopausa e com axila clinicamente negativa talvez pudessem ter a alternativa de não dissecara axila de forma radical (e com isso não correr o risco de edema do braço), sem aumentara chance de falha de tratamento. O presente artigo discute o problema da dissecção da axila no tratamento do câncer da mama e mostra dados de 148 pacientes que fizeram tratamento conservador no Centro de Oncologia Campinas, metade das quais sem dissecção da axila

    The association of p16INK4A and fragile histidine triad gene expression and cervical lesions

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    Objective. This cross-sectional study was intended to assess the association between immunohistochemical analysis of p16INK4A and fragile histidine triad (FHIT) and the presence of precancerous cervical lesions. Materials and Methods. Women seen at Pe´ rola Byington Hospital, São Paulo, Brazil, with histologically confirmed cervicitis (n = 31), cervical intraepithelial neoplasia (CIN) 1 (n = 30), CIN 2,3 (n = 30), and cervical cancer (n = 7) had also cervical material collected for liquid-based cytology, human papillomavirus Hybrid Capture 2 (HC2) test, and p16 and FHIT immunohistochemical reactions. Results. p16 and FHIT reactions were scored as the following: G1%, 1% to 5%, 95% to 25%, and 925%. Receiver operating curve analysis was used to select p16 and FHIT score cutoffs for further categorical analyses. All but one of the 37 CIN 2,3/cancer cases had a p16 score of greater than 1% to 5%. Among the 61 cervicitis/CIN 1 cases, 46 (75%) had a p16 score lower than 1% to 5%. In contrast, no association of FHIT expression and severity of cervical lesions could be demonstrated in this data set. Receiver operating curve analyses suggested the score of 1% to 5% for p16 as the cutoff that best discriminates CIN 2,3/cancer from cervicitis/CIN 1. No cutoff for FHIT scores could be suggested with data set. Conclusions. p16, but not FHIT expression, has the potential to be used as complementary diagnostic tool to investigate human papillomavirusYinduced cervical lesions, if these results are confirmed in larger studies.(undefined
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