1,931 research outputs found

    Feeding Habits and Sexual Dimorphism of the Violet Goby, Gobioides broussoneti Lacepede (Pisces: Gobiidae), in the Estuarine System of Tecolutla, Veracruz, Mexico

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    Gobioides broussoneti were sampled in Silveña estuary, a branch of the Tecolutla estuary, Veracruz, Mexico, during 2 trips made between February 1998 and June 1999 to evaluate diet and sexual dimorphism. A total of 65 G. broussoneti ranging from 49–401 mm SL (0.7–124.2 g WW) were collected. There was a 1:1.2 sex ratio in favor of females. Seven food types were noted, with filamentous algae (25.4%) and detritus (21.3%) representing the principal food types. A 24 h feeding study revealed that this species feeds continuously throughout the day. The ovaries of all female G. broussoneti contained previtellogenic oocytes, characteristic of immature or regressed fish. In contrast, the lobular testis of the males contained late stages of spermatogenesis, suggesting that the fish examined were at the end of the reproductive season. Sexual dimorphism of G. broussoneti is distinguished by a small urogenital papilla, which is in the ventral region between the anal orifice and the anal fin origin. In the females it is short, blunt and has a yellow coloration; in males it is thin, pointed and has a smooth appearance. Only immature or regressed females were captured during this study indicating that G. broussoneti uses the Tecolutla estuary as a nursery and feeding ground. Questions about reproductive seasonality, ovarian development, and spawning of G. broussoneti need further investigation

    Physically-sound simulation of low-velocity impact on fiber reinforced laminates

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    A high-fidelity virtual tool for the numerical simulation of low-velocity impact damage in unidirectional composite laminates is proposed. A continuum material model for the simulation of intraply damage phenomena is implemented in a numerical scheme as a user subroutine of the commercially available Abaqus finite element package. Delaminations are simulated using of cohesive surfaces. The use of structured meshes, aligned with fiber directions allows the physically-sound simulation of matrix cracks parallel to fiber directions, and their interaction with the development of delaminations. The implementation of element erosion criteria and the application of intraply and interlaminar friction allow for the simulation of fiber splits and their entanglement, which in turn results in permanent indentation in the impacted laminate. It is shown that this simulation strategy gives sound results for impact energies bellow and above the Barely Visible Impact Damage threshold, up to laminate perforation condition

    A pitfall for classification

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    High-efficiency kesterite-based thin film solar cells typically feature Cu- poor, Zn-rich absorbers although secondary phases occur easily in non- stoichiometric Cu2ZnSnSe4. We therefore applied high-resolution X-ray fluorescence analysis using a synchrotron nanobeam to study the local composition of a CZTSe cross section lamella cut from a sample with an integral composition of Zn/Sn = 1.37 and Cu/(Zn+Sn) = 0.55. We find submicrometer-sized ZnSe-, SnSe/SnSe2-, and even CuSe/Cu2Se-like secondary phases, while the local compositions of the kesterite are highly Zn-rich yet barely Cu-poor with 1.5 ≤ Zn/Sn ≤ 2.2 and Cu/(Zn+Sn) ∼ 1.0. Consequently, great care must be taken when relating the integral composition to other material properties including the device performance

    Assessing myometrial infiltration by endometrial cancer: uterine virtual navigation with three-dimensional US

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    To describe and analyze the diagnostic performance of uterine virtual navigation with three-dimensional (3D) ultrasonography (US) for the assessment of the depth of myometrial infiltration by endometrial cancer. MATERIALS AND METHODS: Institutional review board approval was obtained; patients gave oral informed consent. Women with endometrial cancer were evaluated by using 3D US prior to surgical staging. A 3D volume of the whole uterus was obtained and analyzed by using software. Virtual navigation through three orthogonal planes was performed to identify the shortest myometrial tumor-free distance to serosa (TDS) by analyzing the lateral, anterior, posterior, and fundal portions of the myometrium. Myometrial infiltration was also assessed by subjective impression of an examiner. Histologic findings of myometrial infiltration and TDS measured by a pathologist were used as the reference standard. A receiver operating characteristic curve was plotted to identify the best cutoff for TDS for identifying myometrial infiltration of 50% or more. RESULTS: Ninety-six women (mean age, 61.8 years; range, 31-86 years) with endometrial cancer were included in the study. At histologic analysis, myometrial invasion was found to be less than 50% in 69 (72%) cases and 50% or more in 27 (28%) cases. TDS measured with US was positively correlated with histologically measured TDS (r = 0.649; 95% confidence interval: 0.52, 0.76). The best cutoff for US-measured TDS was 9.0 mm (sensitivity, 100%; specificity, 61%; negative predictive value, 100%; positive predictive value, 50%). Subjective impression had a sensitivity of 92.6%, a specificity of 82.3%, a negative predictive value of 96.6%, and a positive predictive value of 67.7%. CONCLUSION: Uterine virtual navigation with 3D US is a reliable method for the assessment of myometrial infiltration in patients with endometrial cancer

    Multiscale thermo-mechanical analysis of multi-layered coatings in solar thermal applications

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    Solar selective coatings can be multi-layered materials that optimize the solar absorption while reducing thermal radiation losses, granting the material long-term stability. These layers are deposited on structural materials (e.g., stainless steel, Inconel) in order to enhance the optical and thermal properties of the heat transfer system. However, interesting questions regarding their mechanical stability arise when operating at high temperatures. In this work, a full thermo-mechanical multiscale methodology is presented, covering the nano-, micro-, and macroscopic scales. In such methodology, fundamental material properties are determined by means of molecular dynamics simulations that are consequently implemented at the microstructural level by means of finite element analyses. On the other hand, the macroscale problem is solved while taking into account the effect of the microstructure via thermo-mechanical homogenization on a representative volume element (RVE). The methodology presented herein has been successfully implemented in a reference problem in concentrating solar power plants, namely the characterization of a carbon-based nanocomposite and the obtained results are in agreement with the expected theoretical values, demonstrating that it is now possible to apply successfully the concepts behind Integrated Computational Materials Engineering to design new coatings for complex realistic thermo-mechanical applications

    The Relationship between Squat Jump Performance and Sprint Profile in Collegiate Track and Field Athletes

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    The squat jump (SJ) necessitates the inter-play of various biomechanical components for better jump performance. Good sprint performance requires the inter-play of many of the same biomechanical components. Researchers have previously examined how the speed, force, velocity, and power interact during sprinting, but have yet to examine how these measures are associated with SJ performance measures. PURPOSE: Examine the relationship between squat jump performance measures and the sprint profile measurements of collegiate track and field athletes. METHODS: Twenty-five athletes (18 males and 7 females) completed two squat jump trials with a linear encoder attached to a 45 lbs. bar placed on the athlete’s upper back. Measures of interest during the concentric phase of the SJ included jump height, maximum force, maximum velocity, maximum power, and rate of force development. Athletes then completed two 30-meter acceleration sprints. The MySprint mobile application was used to acquire the athlete’s sprint profile and to assess maximal theoretical horizontal force, maximal theoretical velocity, optimal velocity, maximal theoretical power, maximal speed, maximal ratio of force, force-velocity slope, and decrease in ratio of force. The best trial was used for statistical analysis. Pearson’s or Spearman’s correlation coefficients were conducted between SJ measures and sprint profile measures. RESULTS: There was a positive correlation between SJ height and maximal speed (r = 0.402; p = 0.042). Maximal power during the SJ was positively correlated with maximal speed (r = 0.476; p = 0.014); optimal velocity (r = 0.469; p = 0.018); maximal theoretical power (r = 0.462; p = 0.018); maximal theoretical velocity (r = 0.452; p = 0.021); theoretical horizontal force (r = 0.431; p = 0.028); and maximal ratio force (r = 0.428; p = 0.029). Maximal velocity during the SJ was correlated with maximal speed (r = 0.519; p = 0.007); maximal theoretical velocity (r = 0.499; p = 0.010); optimal velocity (r = 0.486; p = 0.014); and maximal theoretical power (r = 0.484; p = 0.012). No other correlations were significant. CONCLUSION: Maximal velocity and power during the concentric phase of the SJ are moderately to strongly correlated with maximal sprinting speed, velocity, and power. SJ height is positively correlated with maximum sprint speed. There is a lack of significant correlations between other measures of the SJ and sprint profile measures. SJ power and velocity are correlated with sprint performance, therefore power and velocity improved through plyometric SJ training may be transferable to achieve better sprint performance

    Reformulating the direct convolution for high-performance deep learning inference on ARM processors

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    We present two high-performance implementations of the convolution operator via the direct algorithm that outperform the so-called lowering approach based on the im2col transform plus the gemm kernel on an ARMv8-based processor. One of our methods presents the additional advantage of zero-memory overhead while the other employs an additional yet rather moderate workspace, substantially smaller than that required by the im2col+gemm solution. In contrast with a previous implementation of a similar zero-memory overhead direct convolution, this work exhibits the key advantage of preserving the conventional NHWC data layout for the input/output activations of the convolution layers.Funding for open access charge: CRUE-Universitat Jaume

    The water supply system as a potential source of fungal infection in paediatric haematopoietic stem cell units

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    Background: We conducted a prospective study to investigate the presence of microfungal contamination in the water supply system of the Oncology Paediatric Institute, São Paulo - Brazil after the occurrence of one invasive Fusarium solani infection in a patient after Haematopoietic Stem Cell Transplantation (HSCT). During a twelve-month period, we investigated the water supply system of the HSCT unit by monitoring a total of fourteen different collection sites.Methods: One litre of water was collected in each location, filtered through a 0.45 mu m membrane and cultured on SDA to detect the presence of filamentous fungi. Physicochemical analyses of samples were performed to evaluate the temperature, turbidity, pH, and the concentration of free residual chlorine.Results: Over the 12 months of the study, 164 samples were collected from the water supply system of the HSCT unit, and 139 of the samples tested positive for filamentous fungi (84.8%), generating a total of 2,362 colonies. Cladosporium spp., Penicillium spp., Purpureocillium spp. and Aspergillus spp. were ranked as the most commonly found genera of mould in the collected samples. of note, Fusarium solani complex isolates were obtained from 14 out of the 106 samples that were collected from tap water (mean of 20 CFU/L). There was a positive correlation between the total number of fungal CFU obtained in all cultures and both water turbidity and temperature parameters. Our findings emphasise the need for the establishment of strict measures to limit the exposure of high-risk patients to waterborne fungal propagules.Conclusions: We were able to isolate a wide variety of filamentous fungi from the water of the HSCT unit where several immunocompromised patients are assisted.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Dept Med, Disciplina Infectol, BR-04024002 São Paulo, BrazilUniv Austral Chile, Inst Clin Microbiol, Valdivia, ChileUniv Antofagasta, Antofagasta, ChileUniversidade Federal de São Paulo, Inst Oncol Pediat, GRAACC, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Disciplina Infectol, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Inst Oncol Pediat, GRAACC, BR-04023062 São Paulo, BrazilFAPESP: 2005/02138-3CNPq: 133621/2007-3CAPES: PNPD 2312/2011CNPq: 150368/2005-4Web of Scienc
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