167 research outputs found
Avaliação de um Algoritmo para Composição Automática de Web Services.
A composição de Web Services é um tema amplamente explorado na literatura sob diferentes aspectos. Contudo, observou-se que essas pesquisas não são voltadas para o processo como um todo: da requisição criada e enviada por um cliente até o recebimento de uma resposta por este, passando antes pelas etapas de composição dos serviços e execução do fluxo de trabalho. A partir dessa brecha, o presente trabalho mostra o desenvolvimento de um sistema – implantado em rede local – capaz de realizar todas as etapas citadas anteriormente, além de medir o tempo gasto em cada uma delas. Para tal, realizou-se a integração entre as ferramentas AWSCS e EPESWS com o objetivo de fazer a avaliação de desempenho de uma composição automática de Web Services. Os resultados aqui exibidos conseguem revelar qual etapa é o gargalo do sistema, ou seja, aquela que leva mais tempo para sua realização
Principles, Insights and Potential Pitfalls of the Non-Invasive Determination of Muscle Oxidative Capacity by Near-Infrared Spectroscopy
Skeletal muscle oxidative capacity is highly plastic, strongly associated with whole-body aerobic capacity (16, 18) and state of health. Loss of muscle oxidative capacity is associated with physical inactivity, aging and chronic disease (17), and has been implicated in the pathophysiology of obesity and diabetes (21). Evaluating these changes has traditionally been limited to invasive or costly assessments (biopsy or ³¹P MRS). To address this, Hamaoka and colleagues developed an innovative, non-invasive approach using near-infrared spectroscopy (NIRS) to quantitatively measure muscle oxygen consumption (mV̇O₂; 12) and use this to infer muscle oxidative capacity based on the mV̇O₂ recovery rate constant (k) (23; later modified 26). This technique has been subsequently used to interpret relative differences in oxidative capacity across a wide range of muscles, ages and disease states (Figure 1C). The purpose of this Viewpoint is to open a discussion on the principles, insights and potential pitfalls of using NIRS to measure k and infer muscle oxidative capacity
Energetics of walking in individuals with cerebral palsy and typical development, across severity and age: A systematic review and meta-analysis
Background:
Individuals with cerebral palsy (CP) report physical fatigue as a main cause of limitation, deterioration and eventually cessation of their walking ability. A consequence of higher level of fatigue in individuals with CP leads to a less efficient and long-distance walking ability.
Research question:
This systematic review investigates the difference in 1) walking energy expenditure between individuals with CP and age-matched typically developing (TD) individuals; and 2) energetics of walking across Gross Motor Function Classification System (GMFCS) levels and age.
Methods:
Five electronic databases (PubMed, Web of Science, CINAHL, ScienceDirect and Scopus) were searched using search terms related to CP and energetics of walking.
Results:
Forty-one studies met inclusion criteria. Thirty-one studies compared energy expenditure between CP and age-matched controls. Twelve studies correlated energy expenditure and oxygen cost across GMFCS levels. Three studies investigated the walking efficiency across different ages or over a time period. A significant increase of energy expenditure and oxygen cost was found in individuals with CP compared to TD age-matched individuals, with a strong relationship across GMFCS levels.
Significance:
Despite significant differences between individuals with CP compared to TD peers, variability in methods and testing protocols may play a confounding role. Analysis suggests oxygen cost being the preferred/unbiased physiological parameter to assess walking efficacy in CP. To date, there is a knowledge gap on age-related changes of walking efficiency across GMFCS levels and wider span of age ranges. Further systematic research looking at longitudinal age-related changes of energetics of walking in this population is warranted
Vagal blockade suppresses the phase I heart rate response but not the phase I cardiac output response at exercise onset in humans
Purpose
We tested the vagal withdrawal concept for heart rate (HR) and cardiac output (CO) kinetics upon moderate exercise onset, by analysing the effects of vagal blockade on cardiovascular kinetics in humans. We hypothesized that, under atropine, the φ1 amplitude (A1) for HR would reduce to nil, whereas the A1 for CO would still be positive, due to the sudden increase in stroke volume (SV) at exercise onset. Methods
On nine young non-smoking men, during 0–80 W exercise transients of 5-min duration on the cycle ergometer, preceded by 5-min rest, we continuously recorded HR, CO, SV and oxygen uptake (˙O2) upright and supine, in control condition and after full vagal blockade with atropine. Kinetics were analysed with the double exponential model, wherein we computed the amplitudes (A) and time constants (τ) of phase 1 (φ1) and phase 2 (φ2). Results
In atropine versus control, A1 for HR was strongly reduced and fell to 0 bpm in seven out of nine subjects for HR was practically suppressed by atropine in them. The A1 for CO was lower in atropine, but not reduced to nil. Thus, SV only determined A1 for CO in atropine. A2 did not differ between control and atropine. No effect on Ï„1 and Ï„2 was found. These patterns were independent of posture. Conclusion
The results are fully compatible with the tested hypothesis. They provide the first direct demonstration that vagal blockade, while suppressing HR φ1, did not affect φ1 of CO
A new interpolation-free procedure for breath-by-breath analysis of oxygen uptake in exercise transients
Introduction: Interpolation methods circumvent poor time resolution of breath-by-breath oxygen uptake ( V Ë™ O 2 ) kinetics at exercise onset. We report an interpolation-free approach to the improvement of poor time resolution in the analysis of V Ë™ O 2 kinetics. Methods: Noiseless and noisy (10% Gaussian noise) synthetic data were generated by Monte Carlo method from pre-selected parameters (Exact Parameters). Each data set comprised 10 ( V Ë™ O 2 )-on transitions with noisy breath distribution within a physiological range. Transitions were superposed (no interpolation, None), then analysed by bi-exponential model. Fitted model parameters were compared with those from interpolation methods (average transition after Linear or Step 1-s interpolations), applied on the same data. Experimental data during cycling were also analysed. The 95% confidence interval around a line of parameters' equality was computed to analyse agreement between exact parameters and corresponding parameters of fitted functions. Results: The line of parameters' equality stayed within confidence intervals for noiseless synthetic parameters with None, unlike Step and Linear, indicating that None reproduced Exact Parameters. Noise addition reduced differences among pre-treatment procedures. Experimental data provided lower phase I time constants with None than with Step. Conclusion: In conclusion, None revealed better precision and accuracy than Step and Linear, especially when phenomena characterized by time constants of <30s are to be analysed. Therefore, we endorse the utilization of None to improve the quality of breath-by-breath V Ë™ O 2 data during exercise transients, especially when a double exponential model is applied and phase I is accounted for
The Relationships between Total Protein Intake, Protein Sources, Physical Activity, and Lean Mass in a Representative Sample of the US Adults
Background: Although dietary protein and physical activity play essential roles in developing and preserving lean mass, studies exploring these relationships are inconsistent, and large-scale studies on sources of protein and lean mass are lacking. Accordingly, the present study examined the relationship between total protein intake, protein sources, physical activity, and lean mass in a representative sample of US adults. Methods: This cross-sectional study analyzed data from 2011–2016 US National Health and Nutrition Examination Survey and corresponding Food Patterns Equivalents Database (n = 7547). Multiple linear regression models were performed to examine the sex-specific associations between total protein intake, protein sources (Dairy, Total Protein Foods, Seafood, and Plant Proteins), physical activity, and lean mass adjusting for demographics, weight status, and total daily energy intake. Results: Total protein intake was inversely related to lean mass in females only (Lean mass index: β= −0.84, 95%CI: −1.06–−0.62; Appendicular lean mass index: β= −0.35, 95%CI: −0.48–−0.22). However, protein sources and physical activity was positively associated with lean mass in males and/or females (p \u3c 0.05). Conclusion. Study results suggest that consuming more protein daily had a detrimental influence on lean mass in females whereas eating high-quality sources of proteins and being physically active are important for lean mass for men and women. However, the importance of specific protein sources appears to differ by sex and warrants further investigation
Effects of step duration in incremental ramp protocols on peak power and maximal oxygen consumption
Purpose: Morton (J Sport Sci 29:307-309, 2011) proposed a model of the peak power attained in ramp protocol ( w · peak ) that included critical power (CP) and anaerobic capacity as constants, and mean ramp slope (S) as variable. Our hypothesis is that w · peak depends only on S, so that Morton's model should be applicable in all types of ramps. The aim of this study was to test this hypothesis by validating Morton's model using stepwise ramp tests with invariant step increment and increasing step duration. Methods: Sixteen men performed six ramp tests with 25W increments. Step duration was: 15, 30, 60, 90, 120 and 180s. Maximal oxygen consumption ( V · O 2 max ) and w · peak were identified as the highest values reached during each test. An Åstrand-type test was also performed. We measured oxygen consumption and ventilatory variables, together with lactate and heart rate. Results: V · O 2 max was the same in all tests; w · peak was significantly lower the longer the step duration, and all values differed from the maximal power of the Åstrand-type test ( w · max ). Morton's model yielded an excellent fitting, with mean CP equal to 198.08±37.46W and anaerobic capacity equal to 16.82±5.69kJ. Conclusions: Morton's model is a good descriptor of the mechanics of ramp tests. Further developments of Morton's model demonstrated that, whereas w · peak is a protocol-dependent variable, the difference between w · max and CP is a constant, so that their values do not depend on the protocol applie
Testing the vagal withdrawal hypothesis during light exercise under autonomic blockade: a heart rate variability study
Introduction. We performed the first analysis of heart rate variability (HRV) at rest and exercise under full autonomic blockade on the same subjects, to test the conjecture that vagal tone withdrawal occurs at exercise onset. We hypothesized that, between rest and exercise: i) no differences in total power (PTOT) under parasympathetic blockade; ii) a PTOT fall under β1-sympathetic blockade; iii) no differences in PTOT under blockade of both ANS branches.
Methods. 7 males (24±3 years) performed 5-min cycling (80W) supine, preceded by 5-min rest during control and with administration of atropine, metoprolol and atropine+metoprolol (double blockade). Heart rate and arterial blood pressure were continuously recorded. HRV and blood pressure variability were determined by power spectral analysis, and baroreflex sensitivity (BRS) by the sequence method.
Results. At rest, PTOT and the powers of low (LF) and high (HF) frequency components of HRV were dramatically decreased in atropine and double blockade compared to control and metoprolol, with no effects on LF/HF ratio and on the normalised LF (LFnu) and HF (HFnu). At exercise, patterns were the same as at rest. Comparing exercise to rest, PTOT varied as hypothesized. For SAP and DAP, resting PTOT was the same in all conditions. At exercise, in all conditions, PTOT was lower than in control. BRS decreased under atropine and double blockade at rest, under control and metoprolol during exercise.
Conclusions. The results support the hypothesis that vagal suppression determined disappearance of HRV during exercise
Nationwide consensus on the clinical management of treatment-resistant depression in Italy: a Delphi panel
Background: Treatment-resistant depression (TRD) is defined by the European Medicines Agency as a lack of clinically meaningful improvement after treatment, with at least two different antidepressants. Individual, familiar, and socio-economic burden of TRD is huge. Given the lack of clear guidelines, the large variability of TRD approaches across different countries and the availability of new medications to meet the need of effective and rapid acting therapeutic strategies, it is important to understand the consensus regarding the clinical characteristics and treatment pathways of patients with TRD in Italian routine clinical practice, particularly in view of the recent availability of esketamine nasal spray. Methods: A Delphi questionnaire with 17 statements (with a 7 points Likert scale for agreement) was administered via a customized web-based platform to Italian psychiatrists with at least 5 years of experience and specific expertise in the field of depression. In the second-round physicians were asked to answer the same statements considering the interquartile range of each question as an index of their colleagues' responses. Stata 16.1 software was used for the analyses. Results: Sixty panellists, representative of the Italian territory, answered the questionnaire at the first round. For 8/17 statements more than 75% of panellists reached agreement and a high consensus as they assigned similar scores; for 4 statements the panellists assigned similar scores but in the middle of the Likert scale showing a moderate agreement with the statement, while for 5 statements there was indecision in the agreement and low consensus with the statement. Conclusions: This Delphi Panel showed that there is a wide heterogeneity in Italy in the management of TRD patients, and a compelling need of standardised strategies and treatments specifically approved for TRD. A high level of consensus and agreement was obtained about the importance of adding lithium and/or antipsychotics as augmentation therapies and in the meantime about the need for long-term maintenance therapy. A high level of consensus and agreement was equally reached for the identification of esketamine nasal spray as the best option for TRD patients and for the possibility to administrate without difficulties esketamine in a community outpatient setting, highlighting the benefit of an appropriate educational support for patients
Relationship between maximal incremental and high-intensity interval exercise performance in elite athletes
This descriptive study aimed to explore the physiological factors that determine tolerance to exertion during high-intensity interval effort. Forty-seven young women (15–28 years old) were enrolled: 23 athletes from Taiwan national or national reserve teams and 24 moderately active females. Each participant underwent a maximal incremental INC (modified Bruce protocol) cardiopulmonary exercise test on the first day and high-intensity interval testing (HIIT) on the second day, both performed on a treadmill. The HIIT protocol involved alternation between 1-min effort at 120% of the maximal speed, at the same slope reached at the end of the INC, and 1-min rest until volitional exhaustion. Gas exchange, heart rate (HR), and muscle oxygenation at the right vastus lateralis, measured by near-infrared spectroscopy, were continuously recorded. The number of repetitions completed (Rlim) by each participant was considered the HIIT tolerance index. The results showed a large difference in the Rlim (range, 2.6–12.0 repetitions) among the participants. Stepwise linear regression revealed that the variance in the Rlim within the cohort was related to the recovery rates of oxygen consumption (), HR at the second minute after INC, and muscle tissue saturation index at exhaustion (R = 0.644). In addition, age was linearly correlated with Rlim (adjusted R = −0.518, p \u3c 0.0001). In conclusion, the recovery rates for and HR after the incremental test, and muscle saturation index at exhaustion, were the major physiological factors related to HIIT performance. These findings provide insights into the role of the recovery phase after maximal INC exercise testing. Future research investigating a combination of INC and HIIT testing to determine training-induced performance improvement is warranted
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