The Acute Effects of Weighted Vest Protocols on 20-Metre Sprint Performance in Youth Soccer Players

This investigation examined the effects of a warm-up containing weighted vest (WV) sprints on subsequent 20-metre sprint time relative to a control (C) condition in youth soccer players (n=12, mean ± SD age 16 ± 0.60 years, height 175.17 ± 5.92 cm and body mass 61.85 ± 5.88 kg). The main experimental trials consisted of three WV conditions at 10, 20 and 30% of body mass (WV10, WV20 and WV30) and C. Participants were required to complete one 20-metre sprint with each of WV conditions or without additional mass as part of C prior to a 20-metre sprint at 4-, 8- and 12-minutes. A two-way repeated measures ANOVA revealed no significant difference between any of the conditions and rest periods (p = >0.05). The between condition effect sizes for 20-metre sprint times were moderate at 4- and 12-minutes post WV10 (d = -0.86 and -1.15, respectively) and 12-minutes post WV20 (d = -0.84) and WV30 (d = -0.80). Moderate effect sizes were also observed at 4-minutes post WV10 (d = -1.04) and WV20 (d = -0.67) for 10-metre sprint times. These findings demonstrate that WV loading has no significant effect on 20-metre sprint time in youth soccer players. However, there is an opportunity for S&C coaches to implement WV warm-ups of no more than 30% body mass to improve 20-metre sprint times

Duration of infection and strain variation in Streptococcus uberis isolated from cows' milk

The duration of infection and pulsed-field gel electrophoresis (PFGE) types of bovine intramammary Streptococcus uberis isolates were examined. Milk samples were collected in duplicate from all 4 glands of 503 cows from 5 herds within 1 to 3 d of parturition and from 113 cows with clinical mastitis in the same herds throughout lactation. Glands from which S. uberis was isolated were resampled at 28-d intervals. The prevalence of S. uberis was 12% for cows around parturition, and the median duration of infection was 16 d. Cows >2 yr old had a longer duration of infection than 2 yr old cows, and duration varied among herds. A total of 173 different PFGE types were identified from a total of 234 S. uberis isolates. Each farm had a unique set of PFGE types. Only 3 PFGE types were common to each of 3 pairs of cows, and these occurred on the same farm. Where S. uberis was isolated on more than one occasion from a gland, only 55% of the PFGE types were the same across time. For cows with multiple glands infected, only one-half (9 of 18) had the same PFGE type in more than one gland. No predominant PFGE type was identified in any herd. It is concluded that there was wide heterogeneity of PFGE types, that the environment rather than other cows was the likely source of S. uberis infections, and that glands may be infected with multiple S. uberis PFGE types over a lactation

The marine Devonian stratigraphy of Great Britain

Exposed marine Devonian rocks of Great Britain are in South-West England where successions together span most of the Devonian Period. The Geological Conservation Review (GCR) sites of the volume are located in Cornwall and Devon, the latter providing the historic stratotype of the Devonian System. Site stratigraphies are linked to basins of three sub-provinces. Those represent different, albeit largely penecontemporaneous, tectonosedimentary regimes of the differing settings of the Rhenohercynian Zone. The sites and their selection criteria based on their international and national importance in understanding Devonian geological history are listed. A History of Research section provides a detailed review of work on the Devonian rocks of the province from 1839, when Sedgwick and Murchison proposed establishment of the system, to the present and the recent recognition of the relationships between its numerous successions and their dependence upon, extensional and contractional tectonic structures and processes. Other sections detail the Stratigraphical Framework of Devonian strata; Devonian Chronostratigraphy, tracing development and refinement of the Series’ and Stages of the system; and Biostratigraphy, in relation to the faunal groups of the province and their relevance to biozone establishment and environmental discrimination. The chapter concludes with an explanation of current understanding of the evolution of the plate settings of the province that determined the nature of the marine Devonian and its stratigraphy in South-West England

The Looe, south Devon and Tavy Basins : the Devonian rifted passive margin successions

The majority of ‘Marine Devonian’ GCR sites are located on the Early to Latest Devonian rocks of central and north Cornwall and south Devon, within the successions of the east–west Looe, South Devon and Tavy basins, their sub-basins and associated highs. This half-graben and full graben complex developed sequentially northwards during the Devonian period by rifting of the Rhenohercynian passive margin. Basin formation and development was initiated in a terrestrial setting, but from the late Early Devonian marine environments prevailed. Each basin and high had its own stratigraphical succession, and there is variation between those of composite sub-basins. From Mid-Devonian times basins were characterised by hemipelagic deposits with turbid flow incursions of predominantly fine-grained northerly derived terrigenous clastics, and the highs developed carbonate platforms with reefs that persisted into the Late Devonian. Associated alkaline basaltic rocks are typical of the continental rifting regime with high extension. The complex basin and high architecture directly determined major structures, folds and thrusts, developed during regional contraction, and review of those structures permits placement of the sites in that structural context. Thirty eight GCR site reports in this chapter are grouped to describe the stratigraphical successions of named basins and highs from south to north through the sub-province. The oldest deposits are in the south, with basins developing later to the north, but there are differing coeval basin and high successions that extend up to the Latest Devonian through the belt. Amongst the sites there are those that provided definitive descriptions of limestone reefs and their changes in time and space through their acme in the Mid-Devonian, and others that are significant for their fossils, such as the ammonoids, corals or conodonts, which fostered classic studies internationally important in Devonian stratigraphy. Together they describe the variety of stratigraphical sequences and their evolution, environmental, sedimentological and palaeontological, in this major setting of the marine Devonian of Britain