The oxygen-conserving potential of the diving response: A kinetic-based analysis     

Guillaume Costalat  Jeremy Coquart  Ingrid Castres  Fabrice Joulia  Olivier Sirost  Eric Clua 《Journal of sports sciences》2017,35(7):678-687

We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO₂]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO₂) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (?0.86 bpm.%^?1) while HR kinetics in NDs steadily decreased throughout BH (?0.47 bpm.%^?1). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P < 0.05). As a result, BHDs showed a [tHb] drop that NDs did not at the end of BH (?7.3 ± 3.2 vs. ?3.0 ± 4.7%, respectively; P < 0.05). The most striking finding of the present study was that BHDs presented an increase in oxygen-conserving efficiency due to substantial shifts in both cardiac and peripheral haemodynamics during simulated BH. In addition, the kinetic-based approach we used provides further credence to the concept of an “oxygen-conserving breaking point” in the human diving response.  相似文献   

Anti-Market Research: Piracy,New Media Metrics,and Commodity Communities     

Jeremy Wade Morris 《Popular Communication》2015,13(1):32-44

Over a decade after Napster’s introduction, file sharing programs still shoulder much of the blame for music and other media’s declining sales. Although labels and industry associations point their fingers at the harm digital piracy and file-sharing cause, they are less likely to admit the extent to which these anti-markets inform everyday decisions. File-sharing technologies create networks of users that serve as profitable data for ratings and metrics agencies. Using a case study of BigChampagne and its relationship to Napster, this article considers how the look, structure, and function of file-sharing software helped turn an economically threatening community into a commodity and how piracy’s disruptive potential is always in tension with processes of commodification.  相似文献   

Assertive Discipline and the 1997 Education White Paper: a reply to Rigoni and Walford     

Richard Melling  Jeremy Swinson 《教育政策杂志》2013,28(4):575-579

  相似文献   

Ironic processing and static balance performance in high-expertise performers   总被引：1，自引：0，他引：1  

Dugdale JR  Eklund RC 《Research quarterly for exercise and sport》2003,74(3):348-352

  相似文献   

Effect of exertional trend during cycle ergometry on postexercise affect     

Kilpatrick M  Hebert E  Bartholomew J  Hollander D  Stromberg D 《Research quarterly for exercise and sport》2003,74(3):353-359

  相似文献   

POLLING AS A MEANS TOWARD PRESIDENTIAL AUTONOMY: EMIL HURJA, HADLEY CANTRIL AND THE ROOSEVELT ADMINISTRATION     

Eisinger  Robert M.; Brown  Jeremy 《Int. Journal of Public Opinion Research》1998,10(3):237-256

  相似文献   

Truth,beauty, and counting     

Jeremy Gray 《Metascience》2010,19(2):211-212

  相似文献   

The Northern Ireland youth training programme: Some outcomes     

Rosemary Kilpatrick 《Irish Educational Studies》2013,32(1):298-314

  相似文献   

RESEARCH SECTION: The self‐esteem of pupils in schools for pupils with social,emotional and behavioural difficulties: myth and reality     

Jeremy Swinson 《British Journal of Special Education》2008,35(3):165-172

The self‐esteem of pupils has long been regarded as a key variable affecting both pupils' learning and behaviour, although the relationship between the two may not be as strong as many in education have always assumed. In this article, Jeremy Swinson, an educational psychologist and honorary lecturer in educational psychology at Liverpool John Moores University, reports the findings from a study in two parts. Firstly, an examination was made of 35 Statements written by officers from seven different education authorities in the north‐west of England for pupils attending two independent schools that specialise in working with pupils with social, emotional and behavioural difficulties (SEBD). It was found that, of the 35 Statements examined, 34 included self‐esteem as one area of special need. The second phase of the study examined the self‐esteem of 60 pupils in four specialist schools for pupils with social, emotional and behavioural difficulties. The results showed that the average scores for self‐esteem for both the primary and secondary sample were very similar to the scores obtained by previous researchers in mainstream schools. However, it was apparent that more pupils than expected appeared to have either very low or very high self‐esteem. In terms of locus of control, it was found that a large number of secondary pupils had a high score although this was not found to be the case for the primary pupils in the sample. Jeremy Swinson discusses these results and presents his analysis of their implications for teachers, educational psychologists and education officers.  相似文献   

Influence of sex and specialty on the prediction of middle-distance running performances using the Mercier et al.’s nomogram     

Jeremy B. Coquart  Daniel Mercier  Montassar Tabben  Laurent Bosquet 《Journal of sports sciences》2015,33(11):1124-1131

The aim was to test the influence of sex and specialty (3000, 5000 and 10000 m) on the validity of middle-distance running performance predictions obtained from the Mercier et al.’s nomogram. Consequently, we examined all official French track running rankings for the 3000-, 5000- and 10000-m events (men and women) from 2006 to 2012. A scoring table was used to determine the runners’ specialties. Only runners who performed in the three distance events within the same year were included (75 women and 400 men). The Mercier et al.’s nomogram was used to predict one running performance from the other two. The results showed no significant difference between actual and predicted running performances (P = 0.77). Female runners had significantly lower performances than male runners (P < 0.001). Specialty did not influence performances (P = 0.11). Very high correlations were found between actual and predicted performances (0.91 < r < 0.99), with the exception of women (r = 0.85) in 5000 m. Moreover, low limits of agreement were obtained for male and female runners, whatever the specialty. These results support the validity of the nomogram to predict running performance in the 3000-, 5000- and 10000-m events for male and female runners, whatever the specialty. The predicted running performances may be used in training programmes (e.g., to prescribe tempo runs) and competitions (e.g., to establish split times).  相似文献