The blood acid base and gastrointestinal response to three different forms of sodium citrate encapsulation

Enterically coated (ENT) or delayed-release (DEL) capsules may lessen gastrointestinal symptoms (GIS) following acute sodium citrate (SC) ingestion, although the effects on blood acid-base balance are undetermined. Fourteen active males ingested 0.4  g.kg−1 body mass (BM) SC, within gelatine (GEL), DEL and ENT capsules or 0.07 g.kg−1 BM sodium chloride control (CON). Blood acid-base balance and GIS were measured for 4 h. Ingestion form had no significant effect on total GIS experienced (GEL: 2 ± 7; DEL: 1  ± 8; ENT: 1 ± 4 AU). Most (7/14) participants experienced zero symp-toms throughout. Peak GIS typically emerged ≤100 min post- ingestion, with a similar time to reach peak GIS between ingestion form (GEL: 36 ± 70; DEL: 13 ± 28; ENT: 15 ± 33 AU). Blood [HCO3−] was significantly higher with ENT versus GEL (ENT: 29.0 ± 0.8; GEL: 28.5 ± 1.1 mmol.L−1, P = 0.037). Acute ingestion of a reduced SC dose elicited minimal GIS, producing significant changes in blood [HCO3−] from rest, irrespective of ingestion form (GEL: 6.0 ± 0.9; DEL: 5.1 ± 1.0; ENT: 6.2 ± 0.8 mmol.L−1). The necessity of individualized ingestion strategies is also challenged, with sustained increases in blood [HCO3−] of ≥4 mmol.L−1 for up to 153 min highlighted. If commencing exercise at peak alkalosis augments subsequent per-formance above starting at a standardized time point where HCO3− is still elevated remains unclear

Information acquisition differences between experienced and novice time trial cyclists

Purpose: To use eye-tracking technology to directly compare information acquisition behavior of experienced and novice cyclists during a self-paced 10 mile (16.1 km) time-trial. Method: Two groups of novice (N=10) and experienced cyclists (N=10) performed a 10-mile self-paced time-trial (TT) on two separate occasions during which a number of feedback variables (speed, distance, power output, cadence, heart rate, and time) were projected within their view. A large RPE scale was also presented next to the projected information and participants. Participants were fitted with a head-mounted eye32 tracker and heart rate monitor. Results: Experienced cyclists performed both time-trials quicker than novices (F1,18=6.8, P=.018) during which they primarily looked at speed (9 of 10 participants) whereas novices primarily looked at distance (6 of 10 participants). Experienced cyclists looked at primary information for longer than novices across the whole time-trial (24.5±4.2% vs. 34.2±6.1%, t18=4.2, P<0.001) and less frequently than novices during the last quarter of the time-trial (49±19 vs. 80±32, t18=-2.6, P=0.009). The most common combination of primary and secondary information looked at by experienced cyclists was speed and distance respectively. Looking at ten different primary-secondary feedback permutations, the novices were less consistent than the experienced cyclists in their information acquisition behavior. Conclusion: This study challenges the importance placed on knowledge of the endpoint to pacing in previous models, especially for experienced cyclists for whom distance feedback was looked at secondary to, but in conjunction with, information about speed. Novice cyclists have a greater dependence upon distance feedback, which they look at for shorter and more frequent periods of time than the experienced cyclists. Experienced cyclists are more selective and consistent in attention to feedback during time-trial cycling

Sodium bicarbonate ingestion and individual variability in time to peak pH

The aim of this study was to determine the individual variability in time to peak pH after the consumption of a 300mg.kg-1 dose of sodium bicarbonate (NaHCO3). Seventeen active males volunteered to participate in the study (mean ± SD: age 21.38 ± 1.5y; mass 75.8 ± 5.8kg; height 176.8 ± 7.6cm). Participants reported to the laboratory where a resting capillary blood sample was taken aseptically from the fingertip. After this, 300 mg.kg-1 of NaHCO3 in 400ml of water with 50ml of flavoured cordial was ingested. Participants then rested for 90 min during which repeated blood samples were procured at 10 minute intervals for 60 mins and then every 5 min until 90 min. Blood pH concentrations were measured using a blood gas analyser. Results suggested that time to peak pH (64.41±18.78 min) was highly variable with a range of 10-85 min and a coefficient of variation of 29.16%. A bi-modal distribution occurred, at 65 and 75 min. In conclusion, researchers and athletes, when using NaHCO3 as an ergogenic aid, should determine, in advance their time to peak pH to best utilise the added buffering capacity this substance allows

Deception has no acute or residual effect on cycling time trial performance but negatively effects perceptual responses.

Feedback deception is used to explore the importance of expectations on pacing strategy and performance in self-paced exercise. The deception of feedback from a previous performance explores the importance of experience knowledge on exercise behaviour. This study aimed to explore the acute and residual effects of the deception of previous performance speed on perceptual responses and performance in cycling time trials.A parallel-group design.Twenty cyclists were assigned to a control or deception group and performed 16.1km time trials. Following a ride-alone baseline time trial (FBL), participants performed against a virtual avatar representing their FBL performance (PACER), then completed a subsequent ride-alone time trial (SUB). The avatar in the deception group, however, was unknowingly set 2% faster than their FBL.Both groups performed faster in PACER than FBL and SUB (p<0.05), but SUB was not significantly different to FBL. Affect was more negative and Ratings of Perceived Exertion (RPE) were higher in PACER than FBL in the deception group (p<0.05).The presence of a visual pacer acutely facilitated time trial performance, but deceptive feedback had no additional effect on performance. The deception group, however, experienced more negative affect and higher RPE in PACER, whereas these responses were absent in the control group. The performance improvement was not sustained in SUB, suggesting no residual performance effects occurred

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

Gender politics in 21st century literacy reform

From 2001 to 2004 Education Queensland undertook significant literacy reform in schools through the Literate Futures Project. Research into the impact of this reform has revealed that significant demands were placed on women at all levels, from those producing resources to those leading change within schools. Although the reform was a government response to globalisation, many women were driven by a commitment to a collaborative approach to professional learning that addressed equity and improving educational outcomes for all students. But what was the cost of this commitment to the project? Failure to acknowledge the emotion work demanded by educational reform effectively silences women and the significant contribution they make. This paper examining a 21st century literacy reform draws on the work of Fraser and Boler to argue for gender justice and acknowledgement of emotion work

Transcription forms and remodels supercoiling domains unfolding large-scale chromatin structures

DNA supercoiling is an inherent consequence of twisting DNA and is critical for regulating gene expression and DNA replication. However, DNA supercoiling at a genomic scale in human cells is uncharacterized. To map supercoiling we used biotinylated-trimethylpsoralen as a DNA structure probe to show the genome is organized into supercoiling domains. Domains are formed and remodeled by RNA polymerase and topoisomerase activities and are flanked by GC-AT boundaries and CTCF binding sites. Under-wound domains are transcriptionally active, enriched in topoisomerase I, “open” chromatin fibers and DNaseI sites, but are depleted of topoisomerase II. Furthermore DNA supercoiling impacts on additional levels of chromatin compaction as under-wound domains are cytologically decondensed, topologically constrained, and decompacted by transcription of short RNAs. We suggest that supercoiling domains create a topological environment that facilitates gene activation providing an evolutionary purpose for clustering genes along chromosomes