Between-year Effects Research Articles

An investigation on main effects and interactions of relative age effects and playing position in female elite football in Germany.

Athlete age-grouping and age-banding has been shown to impact sport participation and athlete development. The current study examined the impact of within-year (WYEs) and between-year effects (BYEs), and their interactions with playing position, on female participation in elite German football. The sample of 1,378 German first-league players revealed expected participation inequities within-year with relatively older players being over-represented and younger players being under-represented. From a between-year perspective there were no participation differences. The interaction of WYEs and BYEs revealed an over-representation of odd-year players in Q1, and Q2 in even years. With respect to the interaction between year effects and playing position, for WYEs the expected effect was present for goalkeepers and defenders, while there was no significant interaction for BYEs. Overall, the results offer insight regarding the impact of system structure on participation, and highlight unique characteristics associated with playing positions.

Seasonal variations in composition, properties, and heat-induced changes in bovine milk in a seasonal calving system

We determined seasonal variations in the composition and characteristics of bovine milk, as well as heat-induced changes in the physicochemical properties of the milk, in a typical seasonal-calving New Zealand herd over 2 full milking seasons. Fat, protein, and lactose contents varied consistently during the year in patterns similar to those of the lactation cycle. Seasonality also had significant effects on milk calcium, ionic calcium, fat globule size, buffering capacity, and ethanol stability, but not on casein micelle size. The ratio of casein to total protein did not vary significantly over the season, but late-season milk had the highest content of glycosylated κ-casein (G-κ-CN) and the lowest content of α-lactalbumin in both years. We observed significant between-year effects on protein, total calcium, ionic calcium, pH, and casein:total protein ratio, which might have resulted from different somatic cell counts in the 2 years. Compared with heating at 90°C for 6 min, UHT treatment (140°C for 5 s) induced greater dissociation of κ-casein, a similar extent of whey protein denaturation, a lower extent of whey protein-casein micelle association, and a larger increase in casein micelle size. Indeed, UHT treatment might have triggered significant dissociation of G-κ-CN, resulting in aggregation among the casein micelles and increased apparent mean casein micelle diameter. Seasonality had significant effects on the partitioning of G-κ-CN between the micelle and the serum phase, the extent of whey protein-casein micelle association under both heating conditions, and the casein micelle size of the UHT milk.

The interaction between within-year and between-year effects across ages in elite table tennis in international and national contexts – A further exploration of relative age effects in sports

ABSTRACT Although relative age effects in sports have been studied worldwide, the underlying mechanisms are still under debate. This study adds to the existing knowledge by providing a further exploration of the within-year and between-year effects and their possible interaction in an individual skill/technique based sport: table tennis. Data of male and female elite players across ages (U15, U18, U21, and senior) were collected from the ranking lists in international (world and Europe) and national contexts (France and the Netherlands). A multi-way frequency analysis per subsample revealed (1) no interaction effects; (2) significant within-year and between-year effects for the U15 players in the international context and male French players; (3) a significant within-year effect in the French U18 category; (4) a significant within-year effect in female European U21; and (5) no within-year effects in the senior category. Table tennis seems to be at risk for within-year and between-year effects specifically within the context of high competitive level for younger players (U15, males, and females), but not for interactions between these effects. Future research should reveal the development of the RAEs over time in a longitudinal study, evaluate influencing constraints, and innovative prevention solutions in a more comprehensive way.

Transmission of Hand, Foot and Mouth Disease and Its Potential Driving Factors in Hong Kong.

Hand-foot-and-mouth disease (HFMD) is a common childhood disease with substantial disease burden in Asia. Mixed results were reported on the associations between HFMD incidence and meteorological factors or school holidays, while limited studies focused on their association on transmissibility. We aimed to measure the transmissibility of HFMD and to examine its potential driving factors in Hong Kong. A likelihood-based procedure was used to estimate time-dependent effective reproduction number (Rt) based on weekly number of HFMD-associated hospitalizations from 2010 to 2014. The associations of between-year effects, depletion of susceptibles, absolute humidity and school holidays with Rt were examined using linear regression. Rt usually started increasing between early spring and summer and peaked in April to May at around 1.1–1.2, followed by a slight rebound in autumn. Depletion of susceptibles and between-years effects explained most of the variances (19 and 13% respectively) in Rt. We found a negative association between depletion of susceptibles and Rt (coefficients ranged from −0.14 to −0.03 for different years), but the estimated effects of absolute humidity and school holidays were insignificant. Overall, HFMD transmission was moderate in Hong Kong and was mainly associated with depletion of susceptibles. Limited impact was suggested from meteorological factors and school holidays.

Between and within-year effects of haying on grassland bird populations and spatial dynamics

In recent years, haying has extended to Iberian Mediterranean dry grasslands potentially threatening grassland birds. We evaluate the between and within-year effects of haying on grassland birds in Alentejo region, Portugal. Our main goals were: (1) to investigate variations on bird abundance and species richness in the fields hayed, with respect to past haying events occurred in a field and its surroundings and; (2) to investigate the shifts in bird abundance, species richness and spatial dynamics resulting from haying a field and its surrounding area in a given year. We conducted grassland bird censuses during the breeding season through point counts from 2012 to 2015. The relationship between bird abundance/richness and past haying events was investigated using Generalized Linear Models whereas within-year effects of haying were analysed using Generalized Additive Models. Bird abundance in a field was positively related with the surface hayed in the vicinity of that field in the previous year. However, contrasting yearly effects were found for non passerines. Also, some species prefer fields with less haying events or surface hayed, whereas others occur mostly in fields frequently managed for haying. Haying a field leads, in the short term, to its abandonment by birds, and thus to a decrease in bird abundance and, for some species, to spatial concentration in surrounding fields offering suitable habitat. We conclude that within-year effects of haying have higher impact on grassland birds than between-year effects. Maintaining haying at low levels by rotating haying yearly through the different fields in each farm and using partial haying may be an adequate way to ensure an effective management of grassland bird populations.

A six year study of earthworm (Lumbricidae) populations in pasture woodland in southern England shows their responses to soil temperature and soil moisture

There are very few studies on the effects of temporal changes in soil properties on ecosystem engineers in UK soils. This study addresses this lack by presenting earthworm diversity data from a six-year seasonality study comprising 72 monthly samples from the litter and soil of pasture woodland in the New Forest, southern England. These data were analysed in the context of soil moisture and soil temperature, key factors affecting earthworm abundance, and factors likely to be strongly affected by future climate change. The data for the whole period were analysed using non-parametric regression and an additive model used to separate within-year and between-year effects. Seasonal patterns are present for all the common species, generally with a maximum in March and a minimum in September. A majority of the five commonest species show a strong decline in abundance during the two extremely dry periods (2002–2003 and 2006). In sharp contrast, the same species showed a relative increase during the very wet summer and autumn of 2007. There was, however, no significant overall trend in either the climate data or the earthworm species data. The epigeic species, Dendrobaena octaedra, showed the largest decline in the driest months which caused a crash to the point where there were no adults sampled during the four dry summer months of 2003. A second congeneric species, Dendrobaena attemsi, also epigeic, appears to have invaded the woodland during the six year period and is increasing rapidly in abundance. This may indicate the start of a shift in the distribution of the two species, as D. octaedra generally has a northern European distribution and is frost-tolerant, while D. attemsi has a southern European distribution and is more drought-tolerant. In contrast, the very wet summer of 2007 seems to have damped the usual periodic seasonal oscillations in earthworm numbers. Endogeic worm species do not show the D. octaedra seasonal pattern as obviously, probably because these species are able to move more freely through the soil and because they are able to aestivate. These changes are likely to be due to a combination of human movement of earthworms (e.g. D. attemsi) and variations in local climate.

Medium-term temporal stability of the helminth component community structure in bank voles (Clethrionomys glareolus) from the Mazury Lake District region of Poland

The structure of helminth communities in wild rodents is subject to seasonal variation, and is dependent on host age within years. Although between-year variation has been monitored, seldom has it been assessed rigorously by appropriate multifactorial analysis with potentially confounding factors taken into account. In this study we tested the null hypothesis that despite seasonal, host age and sex effects, helminth communities should show relative stability between years. Over a period of 3 years (1998-2000) we sampled bank vole (Clethrionomys glareolus) populations (total n = 250) at 2 points in the year: in spring, at the start of the breeding season, and in autumn, after the cessation of breeding. In spite of seasonal differences and strong age effects, the between-year effects were surprisingly small. Measures of component community structure (Berger-Parker dominance index, the dominant species, S. petrusewiczi) did not vary, or varied only slightly from year to year. The majority of measures of infracommunity structure [Brillouin's index of diversity, prevalence of all helminths combined, prevalence and abundance of H. mixtum (the most prevalent helminth), mean species richness] did not differ significantly between years when other factors such as age, sex and seasonal variation had been taken into account. Some between-year variations were found (at the component community level, Simpson's index of diversity; at the infracommunity level, prevalence and abundance of S. petrusewiczi and abundance of all helminths combined), but even these were modest in comparison to seasonal and age differences, and were primarily attributable to S. petrusewiczi. We conclude that despite dynamic within-year fluctuations, helminth communities in bank voles in this region of Poland show relative stability across years. The sporadic occurrence of individual platyhelminths at low prevalence, makes little difference to the overall structure, which is largely maintained by the key roles played by the dominant intestinal nematodes of bank voles and the rarer species collectively.

Fitting growth models to length frequency data

Abstract A novel two-stage procedure for fitting growth curves to length frequency data collected from commercial fisheries is described. The method is suitable for species in which cohorts are spawned over a limited time period, and samples of length frequency data are collected regularly (e.g. in weekly, fortnightly, or monthly time intervals) over an extended time period. In the first stage of analysis, Gaussian mixtures are fitted separately to the data for each time interval, and summary statistics (component means and standard errors) are extracted. In the second stage, parametric growth models, such as the von Bertalanffy seasonal growth curve, are fitted to the summary data. The error structure in this second stage of analysis incorporates random between-year effects, random within-year age-group effects, random within-year time-interval effects, random within-year age-group and time-interval interactions, and sampling errors. This complex error structure incorporating unbalanced crossed and nested random effects acknowledges that commercial fishing is not an exercise in random sampling, and allows for the inevitable additional sources of random variation in such an enterprise. The method is applied to South Australian southern bluefin tuna length frequency data collected from 1964 to 1989, and leads to the conclusion that juvenile tuna grew faster in the 1980s than in the 1960s, with the 1970s being a decade of highly variable growth.

The effect of sowing date on the growth and production of Lunaria annua in Southern England

Lunaria annua L. is a biennial which has a cold temperature vernalisation requirement. It is widely grown in many temperate countries as an ornamental flower. Interest in the species as an industrial crop has developed from the discovery that it has a seed oil content of 30–40% which contains high levels of erucic (C22.1) and nervonic (C24) acids. An experiment was carried out over the period 1993–1995 to investigate the production potential of the cultivars Kings Crown Purple and White and Monnaie du Pape and the effect of sowing in June, July or August. Plant establishment was between 30 and 40% of seed sown, considerable plant loss occurred over the growing period. Plants sown in June and July flowered early in the following April of both years. Flowering of August sown plants was variable, in 1994 less than 5% flowered, but in 1995 the majority flowered. Albugo candida was recorded on leaves and pods in both years. Seed yield from June and July sowings averaged 2.11 t ha −1 in 1994 and 1.25 t ha −1 in 1995. The purple flowered types (Kings Crown Purple and Monnaie du Pape) out-yielded the white flowered type in both years. Yield differences between June and July sowing dates were small. In 1994 August sown plants did not produce a harvestable yield; in 1995 their yield was significantly lower than other sowing dates. Seed oil and its composition of erucic and nervonic acid averaged 29.9, 50.2 and 22.6%; between-year effects were greater than cultivar and sowing date effects.

Mixed grazing of cattle and sheep versus cattle only in an intensive grassland system

ABSTRACTDuring the period 1974-77 six blocks of a perennial ryegrass/white clover sward were each divided into two for rotational paddock-grazing and silage cutting in alternate years. For each use an annual total of 360 kg nitrogen per ha was applied. Six livestock treatments of cattle only or cattle and sheep were grazed on the blocks. The stocking rates per ha and combinations of cattle (yearling steers) and sheep (ewes nursing twin lambs) respectively were low, 7·5 + 0; medium, 10 + 0, 7·5 + 5, and 5+10; and high, 7·5 + 10 and 5 + 15.The annual quantities of herbage organic matter accumulated (6·6 to 7·2 t/ha) and consumed (5·6 to 6·7 t/ha) did not differ markedly according to grazing treatment during an individual year, nor was there an effect on organic matter accumulation in subsequent conservation years (11·3 to 12·0 t/ha). Between-year effects were significant. As judged by persistence of sown species there was no evidence of sward deterioration over the 4 years.Total live-weight gain per ha increased with increasing stocking rate but with a decreasing increment. The ranges were 106 to 1·42 t/ha within treatments, 102 to 1/45 t/ha within years and 0·97 to 1·8t/ha within treatments × years. Individual gains of cattle (0·67 to 0·88 kg/day) and lambs (0·20 to 0·27 kg/day), and the proportion of lambs ready for slaughter (0·53 to 0·97), were lowest at the highest stocking rate. Mixed grazing compared with cattle-only led to improved cattle gains and improved total gains per ha. The benefits of mixed grazing for a species tended to increase as the proportion of that species in the mix decreased.