Reference values for the incremental shuttle walk test in patients with cardiovascular disease entering exercise-based cardiac rehabilitation     

Fernando M.F. Cardoso  Meshal Almodhy  Garyfalia Pepera  Dimitrios M. Stasinopoulos 《Journal of sports sciences》2017,35(1):1-6

The incremental shuttle walk test (ISWT) is used to assess functional capacity of patients entering cardiac rehabilitation. Factors such as age and sex account for a proportion of the variance in test performance in healthy individuals but there are no reference values for patients with cardiovascular disease. The aim of this study was to produce reference values for the ISWT. Participants were n = 548 patients referred to outpatient cardiac rehabilitation who underwent a clinical examination and performed the ISWT. We used regression to identify predictors of performance and produced centile values using the generalised additive model for location, scale and shape model. Men walked significantly further than women (395 ± 165 vs. 269 ± 118 m; t = 9.5, P < 0.001) so data were analysed separately by sex. Age (years) was the strongest predictor of performance in men (β = ?5.9; 95% CI: ?7.1 to ?4.6 m) and women (β = ?4.8; 95% CI: ?6.3 to 3.3). Centile curves demonstrated a broadly linear decrease in expected ISWT values in males (25–85 years) and a more curvilinear trend in females. Patients entering cardiac rehabilitation present with highly heterogeneous ISWT values. Much of the variance in performance can be explained by patients’ age and sex. Comparing absolute values with age-and sex-specific reference values may aid interpretation of ISWT performance during initial patient assessment at entry to cardiac rehabilitation.  相似文献   

Laboratory predictors of uphill cycling performance in trained cyclists     

Arthur Henrique Bossi  Pedro Lima  Jorge Perrout de Lima  James Hopker 《Journal of sports sciences》2017,35(14):1364-1371

ABSTRACT

This study aimed to assess the relationship between an uphill time-trial (TT) performance and both aerobic and anaerobic parameters obtained from laboratory tests. Fifteen cyclists performed a Wingate anaerobic test, a graded exercise test (GXT) and a field-based 20-min TT with 2.7% mean gradient. After a 5-week non-supervised training period, 10 of them performed a second TT for analysis of pacing reproducibility. Stepwise multiple regressions demonstrated that 91% of TT mean power output variation (W kg^?1) could be explained by peak oxygen uptake (ml kg^?1.min^?1) and the respiratory compensation point (W kg^?1), with standardised beta coefficients of 0.64 and 0.39, respectively. The agreement between mean power output and power at respiratory compensation point showed a bias ± random error of 16.2 ± 51.8 W or 5.7 ± 19.7%. One-way repeated-measures analysis of variance revealed a significant effect of the time interval (123.1 ± 8.7; 97.8 ± 1.2 and 94.0 ± 7.2% of mean power output, for epochs 0–2, 2–18 and 18–20 min, respectively; P < 0.001), characterising a positive pacing profile. This study indicates that an uphill, 20-min TT-type performance is correlated to aerobic physiological GXT variables and that cyclists adopt reproducible pacing strategies when they are tested 5 weeks apart (coefficients of variation of 6.3; 1 and 4%, for 0–2, 2–18 and 18–20 min, respectively).  相似文献   

An analysis of question asking on scientific texts explaining natural phenomena     

Jorge Costa  Helena Caldeira  Juan R. Gallstegui  Jos Otero 《科学教学研究杂志》2000,37(6):602-614

This article relays results of a study focused on questions invoked to correct declarative knowledge deficits while readers process science texts explaining natural phenomena. Firstly, the authors focused on finding out what kind of questions are asked by students who read these texts and, secondly how task demand influences quantity and quality of formulated questions. Two hundred and eighty nine Portuguese students from 8th, 10th, and 12th grade participated in the study. The students were instructed to ask questions on two short science paragraphs that explained natural phenomena. Three task conditions were chosen. Thus, in the “Class” condition, the task was introduced as an activity aimed at developing the capacity to ask questions. In the “Examination” condition, the task was presented as a test on question generation. Finally, in the “Extra‐academic” condition the questioning task was camouflaged as a participation in a research project sponsored by the Ministry of Education and geared at the improvement of science textbooks. The results have shown that students are able to ask many questions when given an opportunity to do so. The study has also proven that students are capable of generating a large volume of causal‐antecedent questions relative to this kind of texts. Finally, no clear effects were found between grade level and/or task demand as defined in the conducted study. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 602–614, 2000  相似文献   

Identifying Temporary and Permanent Gaps in Universal Service     

Jorge Reina Schement  Scott C. Forbes 《The Information Society》2000,16(2):117-126

This article examines the nature of the gap in household telephone penetration among Whites, Blacks, and Hispanics. By analyzing historic and current penetration levels of the radio, television, and telephone, it suggests that most information technology gaps are amalgamations of smaller socioeconomic trends and can be discerned and reduced only with careful historical analysis of both technology choices and living patterns. It proposes localized universal service strategies, since the penetration gaps are affected by a complex array of factors more particular to localities than to the country as a whole and as such must be investigated with rigor and caution if progress toward the elimination of penetration gaps is to occur.  相似文献   

Influence of different sports on bone mass in growing girls     

Esther Ubago-Guisado  Alba Gómez-Cabello  Javier Sánchez-Sánchez  Jorge García-Unanue  Leonor Gallardo 《Journal of sports sciences》2015,33(16):1710-1718

The aim of this study was to analyse whether there are differences in bone mass in girls playing different sports. Two hundred girls (10.6 ± 1.5 years old, Tanner stages I–III) participated in the study and were divided into groups of 40 (swimmers, soccer players, basketball players, handball players and controls). Bone mineral content and bone mineral density (BMD) (whole body and hip) were measured using dual-energy X-ray absorptiometry. The degree of sexual development was determined using Tanner test, and physical activity habits were recorded through a questionnaire designed ad hoc for this research. Girls were divided by pubertal stage and the type of sport. In the prepubertal group, intertrochanteric BMD was significantly higher in both handball and soccer players compared with the control group (P < 0.05). Furthermore, in the pubertal group, total BMD, mean arms BMD, pelvis BMD, femoral neck BMD, intertrochanteric BMD and Ward’s triangle BMD were significantly higher in soccer and handball players compared with the control group (P < 0.05), and the swimmers showed significantly higher values in the mean arms BMD compared with the control group (P < 0.01). Our data suggest that sport practice during puberty, especially in activities that support the body weight, may be an important factor in achieving a high peak bone mass and improving bone health in girls.  相似文献   

随机扩增多态性DNA技术研究发现二氧化钛纳米颗粒对西葫芦具有基因毒性     

Fabiola MORENO-OLIVAS  ;Vincent U.GANT Jr  ;Kyle L.JOHNSON  ;Jose R.PERALTA-VIDEA  ;Jorge L.GARDEA-TORRESDEY 《浙江大学学报(A卷英文版)》2014,15(8):618-623

研究目的：二氧化钛（TiO2）纳米颗粒已经广泛应用于化妆品、防晒霜、涂料和牙膏等。这些纳米颗粒性质非常稳定,能在废水和生物固体中转移和分散。现有研究表明,TiO2纳米颗粒对动物正常生理活动具有毒性等负面作用。但是,它们对植物是否具有毒性特别是是否会产生植物基因毒性至今尚不清楚。因此,本文使用随机扩增多态性DNA技术研究TiO2纳米颗粒是否对西葫芦具有基因毒性,为TiO2纳米颗粒排放进入环境后的潜在植物毒性风险评价提供依据。 创新要点：首次发现了TiO2纳米颗粒对西葫芦具有基因毒性。 重要结论：采用随机扩增多态性DNA技术,发现TiO2纳米颗粒污染处理的西葫芦样品与未处理样品的基因组DNA图谱相比,不仅在谱带强度有明显差异,而且存在谱带消失和新谱带产生现象,表明TiO2纳米颗粒对西葫芦具有基因毒性。  相似文献   

An empirical investigation of mobile government adoption in rural China: A case study in Zhejiang province     

Yong Liu  Hongxiu Li  Vassilis Kostakos  Jorge Goncalves  Simo Hosio  Feng Hu 《Government Information Quarterly》2014

This study is among the first attempts to empirically investigate the adoption of mobile government by rural populations in developing economies. Based on 409 validated questionnaires collected from families living in rural China, the study examines the interdependences among rural inhabitants' demographic attributes, their access to and perceptions of mobile government, and quantifies how their intention to use mobile government is influenced by technology attributes, social factors and trust beliefs. The results indicate that young males, who live far from a village center or market, and have some knowledge of recent government policies, tend to have a more positive perception of mobile government, and therefore become potential adopters of the service. Perceived ease of use, near-term usefulness, long-term usefulness, integrity, benevolence, image and social influence have significant and positive influences on the intention to use mobile government. Specifically, perceived ease of use, long-term usefulness and social influence have a direct influence on intention to use, while perceived near-term usefulness, integrity, benevolence and image have an indirect influence.  相似文献   

Discrete-time modeling and control of a boost converter by means of a variational integrator and sliding modes     

Jorge Rivera  Florentino Chavira  Alexander Loukianov  Susana Ortega  Juan J. Raygoza 《Journal of The Franklin Institute》2014

This work deals with the discrete-time modeling of a boost DC-to-DC power converter by means of a discrete Lagrangian formulation based on the midpoint rule integration method. Then in the basis of this model, a discrete-time sliding mode regulator is designed in order to force the boost circuit to track a DC-biased sinusoidal signal. Simulations and experimental tests are carried on where the great performance of the proposed methodology is verified.  相似文献   

A pictorial view of the physical activity socialization of young adolescents outside of school     

Beets MW  Banda JA  Erwin HE  Beighle A 《Research quarterly for exercise and sport》2011,82(4):769-778

Childhood obesity prevention has fallen short of anticipated impact. Therefore, intervention programs need to be redirected to other potential settings to increase youth physical activity. This qualitative study, using autodriven interview techniques, was conducted to identify out-of-school settings that youth perceive as important for physical activity. Sixty-six children took photographs involving their physical activity involvement. A subsample completed follow-up focus groups. Salient themes included types of physical activities related to free play, fitness, organized sports, and chores. Most photographs included multiple children of similar age and were taken outdoors. Data suggest children associate chores with physical activity and engage in fitness-related activities. In addition, friends and family, the outdoors, and importantly, the home emerged as natural intervention components that may prove useful towards decreasing the physical inactivity and obesity of youth.  相似文献   

Perceptions of Video Scenarios to Learn Human Pathophysiology Among Undergraduate Science Students     

Chen  Hui  Power  Tamara  Hayes  Carolyn  Reyna  Jorge  van Reyk  David 《Journal of Science Education and Technology》2020,29(5):597-604

Pathophysiology describes and explains the physiological dysfunctions that occur in human diseases. Pathophysiology is content heavy, often leading to medical/biomedical science students adopting a surface approach to learning. To encourage more engagement, we developed clinical simulation practical classes using manikin patients. Students considered these were more effective than paper-based case studies. However, they found the first encounter with the manikins daunting. In addition, they did not have a strong sense of responsibility towards the outcome of their treatment choices largely because they recognized this as a simulated experience. Video is a powerful teaching tool to demonstrate situations that are difficult to explain in words, to see theory applied to practice or create enthusiasm and confidence in the viewer regarding the use of new practices. In this study, we evaluated the effectiveness of exposure to a video scenario, in which a high-fidelity manikin was used as the ‘patient’, before the students’ own interactions with the manikin in later classes. Survey results suggested that the students felt more engaged with the case study. They felt the video helped them appreciate aspects of clinical communication and prepare for their time in the simulation laboratory interacting with the manikin. They saw the video as a useful addition to the written case study notes. Their criticisms were mainly around the production quality. This study supports the use of video scenarios as a valuable adjunct to the teaching of pathophysiology to medical/biomedical science students when using either paper- or simulation-based case studies.

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