Reliability of a high-intensity endurance cycling test.

This study assessed the reproducibility of performance and selected metabolic variables during a variable high-intensity endurance cycling test. 8 trained male cyclists (age: 35.9 ± 7.7 years, maximal oxygen uptake: 54.3 ± 3.9 mL·kg - 1·min - 1) completed 4 high-intensity cycling tests, performed in consecutive weeks. The protocol comprised: 20 min of progressive incremental exercise, where the power output was increased by 5% maximal workload (Wmax) every 5 min from 70% Wmax to 85% Wmax; ten 90 s bouts at 90% Wmax, separated by 180 s at 55% Wmax; 90% Wmax until volitional exhaustion. Blood samples were drawn and heart rate was monitored throughout the protocol. There was no significant order effect between trials for time to exhaustion (mean: 4 113.0 ± 60.8 s) or total distance covered (mean: 4 6126.2 ± 1 968.7 m). Total time to exhaustion and total distance covered showed very high reliability with a mean coefficient of variation (CV) of 1.6% (95% Confidence Intervals (CI) 0.0 ± 124.3 s) and CV of 2.2% (95% CI 0.0 ± 1904.9 m), respectively. Variability in plasma glucose concentrations across the time points was very small (CV 0.46-4.3%, mean 95% CI 0.0 ± 0.33 to 0.0 ± 0.94 mmol·L - 1). Plasma lactate concentrations showed no test order effect. The reliability of performance and metabolic variables makes this protocol a valid test to evaluate nutritional interventions in endurance cycling

The effect of moving on union dissolution

This paper examines the effect of migration and residential mobility on union dissolution among married and cohabiting couples. While there is a large, multi-disciplinary literature looking at the determinants of union dissolution in Europe and North America, the possible impact of geographical mobility has received little attention. This is despite the fact that moving is a stressful life event and that numerous studies suggest that women’s economic well-being and employment suffer from family moves which are usually stimulated by the man’s career. We base our longitudinal analysis on retrospective event-history data from Austria and apply hazard regression. Our results show that couples who move frequently have a significantly higher risk of union dissolution. We argue that frequent moving increases couple stress and union instability through a variety of mechanisms.Austria, dissolution of marriage, event history analysis, internal migration, residential mobility

Migration after union dissolution in the United States:The role of non-resident family

Separation from a spouse or cohabiting partner is associated with a high likelihood of moving, even over long distances. In this paper, we use longitudinal data from the Panel Study of Income Dynamics for the United States to analyze the role of non-resident family in the migration of separated people immediately after and in the years following union dissolution. We explore both migration in general and return migration among separated people, drawing comparisons to married and never-married people. We find that having parents, children, or siblings living close by substantially deters migration, especially among separated people. We also find marked positive effects of having family members in the county where the respondent grew up on the likelihood of returning there. Separated people are especially likely to return, compared to others, if they have parents in their county of origin. Furthermore, a lack of an effect of years of education on migration, and a negative effect of this variable on return migration, suggest that migration after separation is less related to human-capital considerations than other types of migration

The chromatin remodeller ACF acts as a dimeric motor to space nucleosomes.

Evenly spaced nucleosomes directly correlate with condensed chromatin and gene silencing. The ATP-dependent chromatin assembly factor (ACF) forms such structures in vitro and is required for silencing in vivo. ACF generates and maintains nucleosome spacing by constantly moving a nucleosome towards the longer flanking DNA faster than the shorter flanking DNA. How the enzyme rapidly moves back and forth between both sides of a nucleosome to accomplish bidirectional movement is unknown. Here we show that nucleosome movement depends cooperatively on two ACF molecules, indicating that ACF functions as a dimer of ATPases. Further, the nucleotide state determines whether the dimer closely engages one or both sides of the nucleosome. Three-dimensional reconstruction by single-particle electron microscopy of the ATPase-nucleosome complex in an activated ATP state reveals a dimer architecture in which the two ATPases face each other. Our results indicate a model in which the two ATPases work in a coordinated manner, taking turns to engage either side of a nucleosome, thereby allowing processive bidirectional movement. This novel dimeric motor mechanism differs from that of dimeric motors such as kinesin and dimeric helicases that processively translocate unidirectionally and reflects the unique challenges faced by motors that move nucleosomes

SU(3) breaking in hyperon transition vector form factors

We present a calculation of the SU(3)-breaking corrections to the hyperon transition vector form factors to $\mathcal{O}(p^4)$ in heavy baryon chiral perturbation theory with finite-range regularisation. Both octet and decuplet degrees of freedom are included. We formulate a chiral expansion at the kinematic point $Q^2=-(M_{B_1}-M_{B_2})^2$, which can be conveniently accessed in lattice QCD. The two unknown low-energy constants at this point are constrained by lattice QCD simulation results for the $\Sigma^-\rightarrow n$ and $\Xi^0\rightarrow \Sigma^+$ transition form factors. Hence we determine lattice-informed values of $f_1$ at the physical point. This work constitutes progress towards the precise determination of $|V_{us}|$ from hyperon semileptonic decays

Imidazopurinones are markers of physiological genomic damage linked to DNA instability and glyoxalase 1-associated tumour multidrug resistance

Glyoxal and methylglyoxal are reactive dicarbonyl metabolites formed and metabolized in physiological systems. Increased exposure to these dicarbonyls is linked to mutagenesis and cytotoxicity and enhanced dicarbonyl metabolism by overexpression of glyoxalase 1 is linked to tumour multidrug resistance in cancer chemotherapy. We report herein that glycation of DNA by glyoxal and methylglyoxal produces a quantitatively important class of nucleotide adduct in physiological systems—imidazopurinones. The adduct derived from methylglyoxal-3-(2′-deoxyribosyl)-6,7-dihydro-6,7-dihydroxy-6/7-methylimidazo-[2,3-b]purine-9(8)one isomers—was the major quantitative adduct detected in mononuclear leukocytes in vivo and tumour cell lines in vitro. It was linked to frequency of DNA strand breaks and increased markedly during apoptosis induced by a cell permeable glyoxalase 1 inhibitor. Unexpectedly, the DNA content of methylglyoxal-derived imidazopurinone and oxidative marker 7,8-dihydro-8-oxo-2′-deoxyguanosine were increased moderately in glyoxalase 1-linked multidrug resistant tumour cell lines. Together these findings suggest that imidazopurinones are a major type of endogenous DNA damage and glyoxalase 1 overexpression in tumour cells strives to counter increased imidazopurinone formation in tumour cells likely linked to their high glycolytic activity

Core Temperature Responses of Fire-fighter Instructors During Work in a Hot and Normal Environment

It is important to employ training practices that ensure that fire-fighter instructors work in an environment which does not provoke unacceptable rises in core temperature (>38°C). PURPOSE: To assess the effects of a two-day fire-behaviour training (FBT) course on the core temperature (Tc) of fire-fighter instructors in order to establish whether current training practices ensure a safe working environment. METHODS: Eleven males (mean±sd age 38.3±4.3 yr, body mass 88.5±12.7 kg and stature 177.8±5.3 cm) from two regional training centres completed three days of standard FBT, wearing full protective clothing and breathing apparatus. Two consecutive days (HOT1 and HOT2, mean ambient temperature of 12.7°C) each consisted of a morning and an afternoon heat exposure (approximately 30 minutes in duration). The third day was a control (NORM), without heat exposure (mean Tc of 19.3 °C). Tc was measured at baseline (BASE) and at the start and end of the two exposures (PRE-AM, POST-AM and PRE-PM, POST-PM respectively) for each subject using a telemetry pill (HQ Inc, USA). RESULTS: There was a different pattern of Tc response over the two HOT days compared with the NORM day due to the significant increase in Tc associated with each of the heat exposures (p<0.01, PRE to POST, Table 1). Mean Tc did not reach 38°C, but in 10 out of 44 individual exposures subjects had a T above 38°C post heat exposure. In contrast, baseline T for the three days was not significantly different and showed a consistent significant increase to PRE-AM values (p<0.01, BASE to PRE-AM, Table 1) associated with the wearing of protective clothing and morning activities. The mean (±sd) unit temperatures of the HOT and NORM days were 160.2 (±89.3) and 27.6 (±8.4) °C respectively. CONCLUSION: The physiological strain experienced due to heat exposure in firefighter instructors resulted in a significant increase in Tc above that experienced during similar physical exertion with no heat exposure. While mean Tc did not reach 38°C, defined as an acceptable limit for work, Tc did rise above 38°C after approximately 1 in 4 individual heat exposures

What are the impacts of within-field farmland management practices on the flux of greenhouse gases from arable cropland in temperate regions? A systematic map protocol

Background: Reducing greenhouse gas emissions is a vital step in limiting climate change and meeting the goals outlined in the COP 21 Paris Agreement of 2015. Studies have suggested that agriculture accounts for around 11% of total greenhouse gas emissions and the industry has a significant role in meeting international and national climate change reduction objectives. However, there is currently little consensus on the mechanisms that regulate the production and assimilation of greenhouse gases in arable land and the practical factors that affect the process. Practical advice for farmers is often overly general, and models based on the amount of nitrogen fertiliser applied, for example, are used despite a lack of knowledge of how local conditions affect the process, such as the importance of humus content and soil types. Here, we propose a systematic map of the evidence relating to the impact on greenhouse gas flux from the agricultural management of arable land in temperate regions. Methods: Using established methods for systematic mapping in environmental sciences we will search for, collate and catalogue research studies relating to the impacts of farming in temperate systems on greenhouse gas emissions. We will search 6 bibliographic databases using a tested search string, and will hand search a web-based search engine and a list of organisational web sites. Furthermore, evidence will be sought from key stakeholders. Search results will then be screened for relevance at title, abstract and full text levels according to a predefined set of eligibility criteria. Consistency checking will be employed to ensure the criteria are being applied accurately and consistently. Relevant studies will then be subjected to coding and meta-data extraction, which will be used to populate a systematic map database describing each relevant study's settings, methods and measured outcomes. The mapping process will help to identify knowledge gaps (subjects lacking in evidence warranting further primary research) and knowledge clusters (subjects with sufficient studies to allow a useful full systematic review), and will highlight best and suboptimal research methods