Assessment of integration method for displacement determination using field accelerometer and geophone data     

F. Lamas-Lopez  Y. J. Cui  S. Costa D’Aguiar  N. Calon 《浙江大学学报(A卷英文版)》2017,18(7):553-566

A conventional French railway track was instrumented with accelerometers and geophones at three depths: sleeper (surface), interlayer (ITL, z=?0.93 m), and transition layer (TL, z=?1.20 m). A linear variable differential transformer (LVDT) was also used to monitor the displacement at the sleeper level. The recorded data allow the integration method (double for accelerometer and simple for geophone) for displacement determination to be assessed. Several questions need to be addressed prior to the selection of an adequate monitoring system: definition of signal filtering processes, influence on results of the different loading wavelengths, repeatability of measurements, train speed and axle load impact and their ranges of validity for each sensor. It was found that the main frequencies that caused more than 95% of the displacement of the monitored materials are in the low frequency range: <25 Hz for trains running up to 200 km/h. For an intercity train, the low frequencies are normally excited by long wavelengths, for instance, those corresponding to the 1/2 coach distance (λ=13.20 m), the bogies distance (λ=6.3 m), and the axle distance (λ=2.8 m). Comparison between the displacements deduced from the records of accelerometer and geophone and obtained from the records of LVDT shows quite consistent results; the mean displacement amplitudes obtained from accelerometers differ by only 20% from the LVDT records. The train speed does not have a strong effect on the obtained differences between sensors. The embedded sensors also gave consistent displacement results for each analysed depth. Moreover, the displacement amplitudes caused by different axle loads (locomotive or passenger coach) are distinguishable for all sensors at all depths. This validates the integration method used for the displacement determination.  相似文献   

Quantifying the interdisciplinarity of scientific journals and fields     

F.N. Silva  F.A. Rodrigues  O.N. Oliveira  L. da F. Costa 《Journal of Informetrics》2013,7(2):469-477

There is an overall perception of increased interdisciplinarity in science, but this is difficult to confirm quantitatively owing to the lack of adequate methods to evaluate subjective phenomena. This is no different from the difficulties in establishing quantitative relationships in human and social sciences. In this paper we quantified the interdisciplinarity of scientific journals and science fields by using an entropy measurement based on the diversity of the subject categories of journals citing a specific journal. The methodology consisted in building citation networks using the Journal Citation Reports^® database, in which the nodes were journals and edges were established based on citations among journals. The overall network for the 11-year period (1999–2009) studied was small-world and followed a power-law with exponential cutoff distribution with regard to the in-strength. Upon visualizing the network topology an overall structure of the various science fields could be inferred, especially their interconnections. We confirmed quantitatively that science fields are becoming increasingly interdisciplinary, with the degree of interdisplinarity (i.e. entropy) correlating strongly with the in-strength of journals and with the impact factor.  相似文献   

Does biological sex impact intestinal epithelial injury,small intestine permeability,gastrointestinal symptoms and systemic cytokine profile in response to exertional-heat stress?     

Rhiannon M. J. Snipe  Ricardo J. S. Costa 《Journal of sports sciences》2013,31(24):2827-2835

ABSTRACT

This study aimed to determine the influence of biological sex on intestinal injury, permeability, gastrointestinal symptoms, and systemic cytokine profile in response to exertional-heat stress. Male (n= 13) and eumenorrheic female (n= 11) endurance runners completed 2 h running at 60% V?O_2max in 35°C. Blood samples were collected pre- and post-exercise and during recovery to determine plasma intestinal fatty-acid binding protein (I-FABP) and systemic cytokine profile. Urinary lactulose:L-rhamnose ratio was used to determine small intestine permeability. I-FABP increased 479% pre- to post-exercise (p< 0.001), with no difference between sexes (p= 0.432). No differences between sexes were observed for small intestine permeability (p= 0.808), gut discomfort, total, upper- and lower-gastrointestinal symptoms. However, males reported significantly higher flatulence (p= 0.049) and abdominal stitch (p= 0.025) compared to females. IL-6, IL-8, IL-10 and IL-1ra increased pre- to post-exercise (p< 0.05), with no difference between sexes. However, IL-1β increased post-exercise in males only, and was higher in males compared to females (p= 0.044). Findings suggest that when females are in the follicular phase of the menstrual cycle, biological sex has no effect on intestinal epithelial injury and permeability, and minimal effect on gastrointestinal symptoms and systemic cytokine profile in response to exertional-heat stress.  相似文献   

A written language intervention for at-risk second grade students: a randomized controlled trial of the process assessment of the learner lesson plans in a tier 2 response-to-intervention (RtI) model     

Stephen R. Hooper  Lara-Jeane C. Costa  Matthew McBee  Kathleen L. Anderson  Donna Carlson Yerby  Amy Childress  Sean B. Knuth 《Annals of dyslexia》2013,63(1):44-64

In a randomized controlled trial, 205 students were followed from grades 1 to 3 with a focus on changes in their writing trajectories following an evidence-based intervention during the spring of second grade. Students were identified as being at-risk (n?=?138), and then randomized into treatment (n?=?68) versus business-as-usual conditions (n?=?70). A typical group also was included (n?=?67). The writing intervention comprised Lesson Sets 4 and 7 from the Process Assessment of the Learner (PAL), and was conducted via small groups (three to six students) twice a week for 12 weeks in accordance with a response-to-intervention Tier 2 model. The primary outcome was the Wechsler Individual Achievement Test-II Written Expression Scale. Results indicated modest support for the PAL lesson plans, with an accelerated rate of growth in writing skills following treatment. There were no significant moderator effects, although there was evidence that the most globally impaired students demonstrated a more rapid rate of growth following treatment. These findings suggest the need for ongoing examination of evidence-based treatments in writing for young elementary students.  相似文献   

Knowledge-intensive consumer services. Understanding KICS in the innovative global health-care sector     

Cátia Miriam Costa  Sandro Mendonça 《Research Policy》2019,48(4):968-982

This paper explores a case of knowledge-intensive consumer services (KICS). Services have become less neglected in the economics of technical change and innovation studies in general; nevertheless, the advance of this agenda has been uneven. A significant emphasis has been on knowledge-intensive business services (KIBS). Despite their direct impact on social needs and individual desires, innovation in consumer-oriented services continues to be relatively under-theorized and under-researched. This paper brings into focus the sources and patterns of innovation in those innovative services that target human satisfaction and well-being as a final goal. We show evidence from a little-explored health industry, oral care. We address Malo Clinic, a company specialized in the most complex patient situations and a rare instance of an internationalized firm in the health services business. On the basis of a 20-year thread of corporate history, we find that a wide array of qualitative (interviews, newspaper coverage, marketing material) and quantitative evidence (papers, patents, trademarks) illuminates some of the features that may characterize a particular class of dynamic activities tending to consumers’ needs, expectations and quality of life. We argue that these key characteristics may be on course to become more general as the learning economy spreads to fully embrace the realm of the service sphere. One conclusion is that both the technological and non-technological capabilities underpinning more types of innovation are increasingly becoming coupled in consumer-relevant services.  相似文献   

Reproducibility of upper leg EMG frequency content during cycling     

Rodrigo Rico Bini  Camila Peter Hoefelmann  Vitor Pereira Costa  Fernando Diefenthaeler 《Journal of sports sciences》2018,36(5):485-491

Reproducibility of frequency content from surface electromyography (sEMG) signals has not been assessed and it is unknown if incremental load testing design could affect sEMG in cycling. The goals of this study were to assess the reproducibility of measures from sEMG frequency content between sessions and to compare these frequency components between a ramp and a step incremental cycling test. Eighteen cyclists performed four incremental load cycling tests to exhaustion. Two tests were performed using a step increment (load started at 100 W for 3 min followed by increments of 30 W every 3 min) and two were performed using a ramp increment (load started at 100 W for 1 min followed by increments of 30 W·min^?1). sEMG was monitored bilaterally for the rectus femoris and vastus lateralis throughout the tests and converted into overall activation (whole signal bandwidth), high- and low-frequency contents. The reproducibility of the frequency content ranged from none to strong (ICC = 0.07–0.90). Vastus lateralis activation was larger at the step compared to the ramp test (P < 0.01), without differences for rectus femoris (P = 0.22–0.91) and for the high-frequency (P = 0.28–0.95) and low-frequency contents (P = 0.13–0.94). sEMG from vastus lateralis and rectus femoris presented none to strong reproducibility. Vastus lateralis is more activated in step test design.  相似文献   

Facilitating adult learning and a researcher identity through a higher education pedagogical process     

Lisa L. Wright Lange Elizabeth Da Costa Jose 《美中教育评论》2009,6(11):1-16

This empirical study uses auto-ethnography to describe a higher education pedagogical process that facilitated largely doctoral students in preparing their candidacy proposals through the use of specific adult learning principles. Students＇ experiences and points of view of such a learning environment were explored, including： （1） how they contributed to their peers＇ learning; （2） how their peers contributed to their own individual learning; and （3） how the learning environment impacted the process. Key factors identified as pivotal to learning to learn, include creating a learning sanctuary and trusting relationships, engaging in mutual inquiry and the co-construction of meaning, and bridging research theory and practice. These factors enabled students to expand their identities to include a researcher identity and to negotiate deep knowledge at the personal level. Throughout this article, the students＇ points of view are used to elucidate shared and diverse experiences, in addition to supporting conclusions and recommendations for practice and further study.  相似文献   

Outdoor play as a mean to achieve educational goals - a case study in a Portuguese day-care group     

Gabriela Bento  Jorge Adelino Costa 《Journal of Adventure Education & Outdoor Learning》2018,18(4):289-302

This study aims to explore the pedagogical potential of outdoor play situations, considering the educational goals established in the Portuguese Pedagogical Guidelines for 0–3-year-old children (ongoing work), namely development of a sense of security and positive self-esteem; development of curiosity and exploratory impetus; and development of social and communication skills. Following a qualitative methodology, during a period of 9 months, the outdoor play experiences of 14 children from a day-care centre were observed and monitored and the professionals were interviewed. The data shows that outdoor experiences can contribute to the achievement of the educational goals, enlarging opportunities for creative play, problem solving, experimentation, inquiry, dialogues and collaboration. The achievement of the educational goals is facilitated through supportive and positive relationships with adults and peers, provision for proper equipment, and contact with nature. This study offers a deep insight into how educational policies can be put into practice in the outdoor area.  相似文献   

The geometric curvature of the spine during the sirshasana,the yoga’s headstand     

Mário Hebling Campos  Nayane Martins Giraldi  Paulo Gentil  Claudio Andre Barbosa de Lira  Carlos A. Vieira  Marcelo Costa de Paula 《Journal of sports sciences》2017,35(12):1134-1141

This study analysed the behaviour of the geometric curvature of the spine during sirshasana. The position of dorsal retroreflective markers was computed via stereophotogrammetric analysis in six males and five females (29.4 ± 8.8 years, 63.0 ± 11.4 kg, 1.66 ± 0.08 m [average ± standard deviation]). The spinal points were projected onto the sagittal and frontal planes of the trunk, a polynomial was fitted to the data and the two-dimensional geometric curvature was quantified. The inferior lumbar lordosis decreased compared to the orthostatic position and gait, which may favour the posterior protrusion of the lumbar spinal nucleus pulposus in people with posterior herniation. The lateral deviation at the middle of the thoracic spine increases during sirshasana, which may reflect increased difficulties for postural control and spinal loads. It could be useful for promoting positive spinal structural and functional chronic adaptations for healthy participants, if the yoga programme is carefully planned and the spinal alignment is carefully monitored during a headstand. However, it may aggravate some spinal diseases, especially scoliosis.  相似文献   

Impact of interdisciplinary learning on the development of engineering students’ skills     

Alexandra R. Costa  Mafalda Ferreira  Ana Barata  Conceição Viterbo  José Salgado Rodrigues  José Magalhães 《European Journal of Engineering Education》2019,44(4):589-601

ABSTRACT

This paper intends to present an interdisciplinary project carried out in a School of Engineering, and to refer to its effects in the development of students’ skills. This project’s main goal was to present students with an intellectually demanding challenge which implied overcoming the disciplinary barriers thus integrating knowledge to solve the problems they were challenged with. After the project had been concluded, a study was carried out using a qualitative methodology by conducting two focus groups (n?=?16). The main goal of this procedure was to get a better perception of (1) how students understood the project; (2) what kind of skills students considered to have developed throughout the project, and (3) the importance they have attributed to this kind of project. The results demonstrate that students are aware of the relevance of the project not only for their education process but also for the development of their skills. The results of the study also reveal that the students involved in the project have been capable of identifying the specific skills that the project work had intended to address and develop.  相似文献