954 research outputs found

    Early maternal experience shapes offspring performance in the wild

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    Both the environments experienced by a mother as a juvenile and an adult can affect her investment in offspring. However, the implications of these maternal legacies, both juvenile and adult, for offspring fitness in natural populations are unclear. We investigated whether the juvenile growth rate and adult reproductive traits (length, body condition, and reproductive investment at spawning) of female wild Atlantic salmon (Salmo salar) were related to the growth and survival of their offspring. Adult salmon captured on their upstream migration were used to create experimental full-sib clutches of eggs, which were mixed and then placed in artificial nests in a natural stream that lacked salmon due to a migration barrier. Four months later we resampled the stream to obtain family-level estimates of offspring size and survival. Mothers that had grown slowly as juveniles (as determined by scalimetry) but had invested heavily in reproduction (egg production for a given body length) and were in relatively poor body condition (somatic mass for a given body length) at spawning produced the largest eggs. Larger eggs resulted in larger juveniles and higher juvenile survival. However, after controlling for egg size, offspring growth was positively related to maternal juvenile growth rate and reproductive investment. The predictors of offspring survival (i.e., reproductive success) varied with the juvenile growth rate of the mother: If females grew slowly as juveniles, their reproductive success was negatively related to their own body condition. In contrast, the reproductive success of females that grew quickly as juveniles was instead related positively to their own body condition. Our results show that maternal influences on offspring in the wild can be complex, with reproductive success related to the early life performance of the mother, as well as her state at the time of breeding

    Interactions between parental traits, environmental harshness and growth rate in determining telomere length in wild juvenile salmon

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    A larger body size confers many benefits, such as increased reproductive success, ability to evade predators and increased competitive ability and social status. However, individuals rarely maximise their growth rates, suggesting that this carries costs. One such cost could be faster attrition of the telomeres that cap the ends of eukaryotic chromosomes and play an important role in chromosome protection. A relatively short telomere length is indicative of poor biological state, including poorer tissue and organ performance, reduced potential longevity and increased disease susceptibility. Telomere loss during growth may also be accelerated by environmental factors, but these have rarely been subjected to experimental manipulation in the natural environment. Using a wild system involving experimental manipulations of juvenile Atlantic salmon Salmo salar in Scottish streams, we found that telomere length in juvenile fish was influenced by parental traits and by direct environmental effects. We found that faster-growing fish had shorter telomeres and there was a greater cost (in terms of reduced telomere length) if the growth occurred in a harsher environment. We also found a positive association between offspring telomere length and the growth history of their fathers (but not mothers), represented by the number of years fathers had spent at sea. This suggests that there may be long term consequences of growth conditions and parental life history for individual longevity

    Speech by the Hon'ble Enche D.C.Stewart at the Presentation Of Cattle And Goats at the Veterinary Department,Balik Pulau on 16th September, 1971.

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    I am very pleased to be with you this morning to hand over 6 buffaloes, 8 cows and 15 goats which are provided by the State under the Second Malaysia Rural Development Plan

    Persistent punishment : users views of short prison sentences

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    Semi-structured interviews were conducted of 22 prisoners to gather information about the characteristic features of short prison sentences. Themes raised in comments included: the frequency and quality of sentences, addiction, family, and penal legitimacy. Most of the participants had extensive experience of prison, and the effects of this played out across sentences and years, accumulating and amplifying impacts. And, despite expressions of guilt and remorse, most participants saw their sentence as unjust, and mainly a reaction to offending history. We conclude by suggesting the need for research to shift focus from evaluating individual penal interventions towards more holistic and narrative accounts that cut across sentences

    Long-term outcome of thyrotoxicosis in childhood and adolescence in the west of Scotland: the case for long-term antithyroid treatment and the importance of initial counselling

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    Background: Thyrotoxicosis is both rarer and more severe in children than in adults, rendering management difficult and often unsatisfactory. Objective: To ascertain outcome in a geographically defined area of Scotland between 1989 and 2014. Method: Retrospective case note review with follow-up questionnaire to family doctors for patients with Graves’ disease and Hashimoto’s thyroiditis. Results: Sixty-six patients (58 females:8 males) comprising 53 with Graves’ disease and 13 with Hashimoto’s thyroiditis were diagnosed at median 10.4 (2.9–15.8) years and followed up for 11.8 (2.6–30.2) years. Antithyroid drug (ATD) therapy was stopped electively in 35 patients after 4.5 (1.5–8.6) years, resulting in remission in 10/13 Hashimoto’s thyroiditis and 10/22 Graves’ disease. Side effects occurred in 12 patients receiving carbimazole, six of whom changed to propylthiouracil; no adverse events occurred in the latter patients. Second-line therapy was given to 37 patients (34 with Graves’ disease), comprising radioiodine (22) at 15.6 (9.3–24.4) years for relapse (6), poor control/adherence (14) or electively (2); and surgery (16) at 12 (6.4–21.3) years for relapse (4), poor control/adherence (5) and electively (7). Adherence problems with thyroxine replacement were reported in 10/33 patients in adulthood. Conclusions: Hashimoto’s thyroiditis should be distinguished from Graves’ disease at diagnosis since the prognosis for remission is better. Remission rates for Graves’ disease are low (10/53 patients), time to remission variable and adherence with both ATD and thyroxine replacement often problematic. We recommend (a) the giving of long-term ATD rather than a fixed course of treatment in GD and (b) meticulous and realistic counselling of families from the time of diagnosis onwards

    Electromagnetic field angular momentum in condensed matter systems

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    Various electromagnetic systems can carry an angular momentum in their {\bf E} and {\bf B} fields. The electromagnetic field angular momentum (EMAM) of these systems can combine with the spin angular momentum to give composite fermions or composite bosons. In this paper we examine the possiblity that an EMAM could provide an explanation of the fractional quantum Hall effect (FQHE) which is complimentary to the Chern-Simons explanation. We also examine a toy model of a non-BCS superconductor (e.g. high TcT_c superconductors) in terms of an EMAM. The models presented give a common, simple picture of these two systems in terms of an EMAM. The presence of an EMAM in these systems might be tested through the observation of the decay modes of a charged, spin zero unstable particle inside one of these systems.Comment: 17 pages, no figures, to be published in Phys. Rev.

    Anthropometric Foot Structure of Peripubescent Children with Excessive versus Normal Body Mass

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    BACKGROUND: A variety of musculoskeletal problems have been associated with excessive body mass in children, including structural foot problems. METHODS: Two hundred children aged 9 to 12 years were recruited to evaluate the effect of body mass on foot structure. Three reliable anthropometric measures were recorded: foot length, forefoot width, and navicular height. RESULTS: Following independent sample t test analysis of the data, significant differences were found for the three anthropometric variables when children with normal body mass were compared with those with excessive body mass. The research indicates that foot length and width increase with body mass, whereas navicular height drops. CONCLUSIONS: Excessive body mass affects the discrete anthropometric structure of the peripubescent foot. With the growing concern about childhood obesity, further research is essential to develop a comprehensive understanding of the issues identified and to quantify the findings presented here

    Electronic Structure and Heavy Fermion Behavior in LiV_2O_4

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    First principles density functional calculations of the electronic and magnetic properties of spinel-structure LiV2_{2}O4_{4} have been performed using the full potential linearized augmented planewave method. The calculations show that the electronic structure near the Fermi energy consists of a manifold of 12 bands derived from V t2gt_{2g} states, weakly hybridized with O p states. While the total width of this active manifold is approximately 2 eV, it may be roughly decomposed into two groups: high velocity bands and flatter bands, although these mix in density functional calculations. The flat bands, which are the more atomic-like lead to a high density of states and magnetic instability of local moment character. The value of the on-site exchange energy is sensitive to the exact exchange correlation parameterization used in the calculations, but is much larger than the interaction between neighboring spins, reflecting the weak coupling of the magnetic system with the high velocity bands. A scenario for the observed heavy fermion behavior is discussed in which conduction electrons in the dispersive bands are weakly scattered by local moments associated with strongly correlated electrons in the heavy bands.This is analogous to that in conventional Kondo type heavy fermions, but is unusual in that both the local moments and conduction electrons come from the same d-manifold.Comment: 6 Revtex pages, Postscript figs embedded. Revision: figure 4 replaced with a better version, showing the band character explicitel

    The views of five participating undergraduate students of the Student Associates Scheme in England

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    This paper reports findings from a study which explored undergraduate perceptions of the Student Associates Scheme in England (SAS). The scheme was established by the Training and Development Agency for Schools in an attempt to increase the number of graduates entering the teaching profession, particularly in shortage subjects such as the physical sciences and mathematics. The scheme places undergraduate students on short-term placements in secondary schools throughout England to provide them with experiences that may encourage them to consider teaching as a career option. Findings show that the SAS school placements were a positive experience for the students participating in this study. However, a question emerged as to whether or not the scheme is targeting students who have yet to decide upon teaching as a career or just reinforcing the existing aspirations of students who have already decided to teach. As the scheme is attempting to increase the number of teachers entering the profession this question has important implications for this study and further work which will focus on undergraduates who think that their career ambitions would not be fulfilled by teaching
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