Resistance training and youth

This is the publisher's version, also found at http://ehis.ebscohost.com/ehost/detail?vid=4&sid=34ab1967-2aea-457b-b261-e90e7b05e38c%40sessionmgr11&hid=2&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=s3h&AN=20752095The use of resistance training for children has increased in popularity and interest. It appears that children are capable of voluntary strength gains. Exercise prescription in younger populations is critical and requires certain program variables to be altered tTom adult perspectives. Individualization is vital, as the rate of physiological maturation has an impact on the adaptations that occur, The major difference in programs for children is the use of lighter loads (i.e., > 6 RM loads). It appears that longer duration programs (i.e., 10-20 wks) are better for observing training adaptations. This may be due to the fact that it takes more exercise to stimulate adaptational mechanisms related to strength performance beyond that of normal growth rates. The risk of injury appears low during participation in a resistance training program, and this risk is minimized with proper supervision and instruction. Furthermore, with the incidence of injury in youth sports, participation in a resistance training program may provide a protective advantage in one's preparation for sports participation

Characteristics of US-Based STEM Webcams \u3cem\u3eat a Glance\u3c/em\u3e

STEM organizations operate thousands of publicly available webcams, which have the potential to provide rich informal learning opportunities. To date, no research has analyzed the breadth of STEM webcams. In our study, we developed an inventory by performing internet searches for US-based STEM webcams and recorded operator name, organization type, webcam subject, etc. This inventory serves as the basis for a follow-up survey of webcam operators, which seeks to better understand the goals, outcomes, and investments of STEM webcam programs. We characterized nearly 1000 webcams that fit within our inclusion criteria. The majority of the cams fell within the life sciences or geosciences. Of the animal webcams, mammals (60%) and birds (23%) were strongly represented in contrast to reptiles (2%) and insects (4%). Within the mammal subjects, tigers, elephants, otters, and giraffes were most common (5-7% each). Within the 23 different bird webcam subjects, penguins (30%) and osprey (20%) were most common. Other studies have shown the over-representation of charismatic animals (e.g., elephants, giraffes, tigers, bears) in zoos, and our study suggests that webcams may amplify this phenomenon. Further, these preliminary results suggest that life sciences topics dominate STEM webcams, leaving potential for other visually engaging fields to participate

Carbon Dynamics On The Louisiana Continental Shelf And Cross-Shelf Feeding Of Hypoxia

Large-scale hypoxia regularly develops during the summer on the Louisiana continental shelf. Traditionally, hypoxia has been linked to the vast winter and spring nutrient inputs from the Mississippi River and its distributary, the Atchafalaya River. However, recent studies indicate that much of the shelf ecosystem is heterotrophic. We used data from five late July shelfwide cruises from 2006 to 2010 to examine carbon and oxygen production and identify net autotrophic areas of phytoplankton growth on the Louisiana shelf. During these summer times of moderate river flows, shelfwide pH and particulate organic carbon (POC) consistently showed strong signals for net autotrophy in low salinity (\u3c25) waters near the river mouths. There was substantial POC removal via grazing and sedimentation in near-river regions, with 66–85 % of POC lost from surface waters in the low and mid-salinity ranges without producing strong respiration signals in surface waters. This POC removal in nearshore environments indicates highly efficient algal retention by the shelf ecosystem. Updated carbon export calculations for local estuaries and a preliminary shelfwide carbon budget agree with older concepts that offshore hypoxia is linked strongly to nutrient loading from the Mississippi River, but a new emphasis on cross-shelf dynamics emerged in this research. Cross-shelf transects indicated that river-influenced nearshore waters \u3c15 m deep are strong sources of net carbon production, with currents and wave-induced resuspension likely transporting this POC offshore to fuel hypoxia in adjacent mid-shelf bottom waters

Electro-elastic tuning of single particles in individual self-assembled quantum dots

We investigate the effect of uniaxial stress on InGaAs quantum dots in a charge tunable device. Using Coulomb blockade and photoluminescence, we observe that significant tuning of single particle energies (~ -0.5 meV/MPa) leads to variable tuning of exciton energies (+18 to -0.9 micro-eV/MPa) under tensile stress. Modest tuning of the permanent dipole, Coulomb interaction and fine-structure splitting energies is also measured. We exploit the variable exciton response to tune multiple quantum dots on the same chip into resonance.Comment: 16 pages, 4 figures, 1 table. Final versio

Catch a tiger snake by its tail: Differential toxicity, co-factor dependence and antivenom efficacy in a procoagulant clade of Australian venomous snakes

A paradigm of venom research is adaptive evolution of toxins as part of a predator-prey chemical arms race. This study examined differential co-factor dependence, variations relative to dietary preference, and the impact upon relative neutralisation by antivenom of the procoagulant toxins in the venoms of a clade of Australian snakes. All genera were characterised by venoms rich in factor Xa which act upon endogenous prothrombin. Examination of toxin sequences revealed an extraordinary level of conservation, which indicates that adaptive evolution is not a feature of this toxin type. Consistent with this, the venoms did not display differences on the plasma of different taxa. Examination of the prothrombin target revealed endogenous blood proteins are under extreme negative selection pressure for diversification, this in turn puts a strong negative selection pressure upon the toxins as sequence diversification could result in a drift away from the target. Thus this study reveals that adaptive evolution is not a consistent feature in toxin evolution in cases where the target is under negative selection pressure for diversification. Consistent with this high level of toxin conservation, the antivenom showed extremely high-levels of cross-reactivity. There was however a strong statistical correlation between relative degree of phospholipid-dependence and clotting time, with the least dependent venoms producing faster clotting times than the other venoms even in the presence of phospholipid. The results of this study are not only of interest to evolutionary and ecological disciplines, but also have implications for clinical toxinology

Academic boredom among students in higher education: a mixed-methods exploration of characteristics, contributors and consequences

Academic boredom contributes usually adversely towards student engagement, learning and overall performance across a diverse range of settings including universities. The formal study of academic boredom in higher education remains, however, a relatively underdeveloped field and one surprisingly neglected in the UK. Adopting contemporary perspectives rooted in Control-Value Theory, details of a mixed-methods exploration of academic boredom among 235 final year undergraduates attending a single university in England are presented. Quantitative data from the principal survey instrument employed included measurement using the BPS-UKHE, a revised boredom proneness scale developed for use across the sector. Qualitative data arose primarily from ten research interviews. Findings indicate that about half of all respondents reported experiencing the most common precursors of academic boredom at least occasionally (e.g. monotony, repetition, time slowing down, lack of desire for challenge, loss of concentration and motivation to learn, restlessness); traditional lectures with a perceived excess and inappropriate use of PowerPoint stimulating the actual onset of boredom more than other interactive forms of delivery. Coping strategies when bored included daydreaming, texting and turning to social media. Boredom also occurred during the completion of assignments used to assess modules. Quantitative and qualitative differences between those identified as more prone to boredom than others extended to self-study (fewer hours), attendance (good rather than excellent) and final degree outcome (lower marks and a lower proportion of first and upper second class degree awards). Findings are considered valuable empirically, as well as theoretically, leading to recommendations surrounding boredom mitigation which challenge cultural traditions and pedagogical norms

Does maternal exposure to an environmental stressor affect offspring response to predators?

There is growing recognition of the ways in which maternal effects can influence offspring size, physiological performance, and survival. Additionally, environmental contaminants increasingly act as stressors in maternal environments, possibly leading to maternal effects on subsequent offspring. Thus, it is important to determine whether contaminants and other stressors can contribute to maternal effects, particularly under varied ecological conditions that encompass the range under which offspring develop. We used aquatic mesocosms to determine whether maternal effects of mercury (Hg) exposure shape offspring phenotype in the American toad (Bufo americanus) in the presence or absence of larval predators (dragonfly naiads). We found significant maternal effects of Hg exposure and significant effects of predators on several offspring traits, but there was little evidence that maternal effects altered offspring interactions with predators. Offspring from Hg-exposed mothers were 18% smaller than those of reference mothers. Offspring reared with predators were 23% smaller at metamorphosis than those reared without predators. There was also evidence of reduced larval survival when larvae were reared with predators, but this was independent of maternal effects. Additionally, 5 times more larvae had spinal malformations when reared without predators, suggesting selective predation of malformed larvae by predators. Lastly, we found a significant negative correlation between offspring survival and algal density in mesocosms, indicating a role for top-down effects of predators on periphyton communities. Our results demonstrate that maternal exposure to an environmental stressor can induce phenotypic responses in offspring in a direction similar to that produced by direct exposure of offspring to predators

Phylogenetic Analysis of the Neks Reveals Early Diversification of Ciliary-Cell Cycle Kinases

NIMA-related kinases (Neks) have been studied in diverse eukaryotes, including the fungus Aspergillus and the ciliate Tetrahymena. In the former, a single Nek plays an essential role in cell cycle regulation; in the latter, which has more than 30 Neks in its genome, multiple Neks regulate ciliary length. Mammalian genomes encode an intermediate number of Neks, several of which are reported to play roles in cell cycle regulation and/or localize to centrosomes. Previously, we reported that organisms with cilia typically have more Neks than organisms without cilia, but were unable to establish the evolutionary history of the gene family

Primary care physicians' use of family history for cancer risk assessment

<p>Abstract</p> <p>Background</p> <p>Family history (FH) assessment is useful in identifying and managing patients at increased risk for cancer. This study assessed reported FH quality and associations with physician perceptions.</p> <p>Methods</p> <p>Primary care physicians practicing in two northeastern U.S. states were surveyed (n = 880; 70% response rate). Outcome measures of FH quality were extent of FH taken and ascertaining age at cancer diagnosis for affected family members. Predictors of quality measured in this survey included: perceived advantages and disadvantages of collecting FH information, knowledge of management options, access to supportive resources, and confidence in ability to interpret FH.</p> <p>Results</p> <p>Reported collection of information regarding second degree blood relatives and age of diagnosis among affected relatives was low. All hypothesized predictors were associated with measures of FH quality, but not all were consistent independent predictors. Perceived advantages of taking a family history, access to supportive resources, and confidence in ability to identify and manage higher risk patients were independent predictors of both FH quality measures. Perceived disadvantages of taking a family history was independently associated one measure of FH quality. Knowledge of management options was not independently associated with either quality measure.</p> <p>Conclusions</p> <p>Modifiable perception and resource factors were independently associated with quality of FH taking in a large and diverse sample of primary care physicians. Improving FH quality for identification of high risk individuals will require multi-faceted interventions.</p