337 research outputs found
Do Not Keep Calm and Carry on: School-Based Mindfulness Programmes Should Test Making Mindfulness Practice Available in the School Day
Recently, the largest test of a school-based mindfulness programme to date, the My Resilience In Adolescence (MYRIAD) trial, found that participating in weekly mindfulness lessons did not improve students’ well-being compared to teaching as usual, with low uptake of recommended home mindfulness practice. One potential explanation for the null result and low uptake is that adolescents might be unlikely to adhere to home mindfulness practice recommendations when choosing between mindfulness and their graded homework or more stimulating activities. Indeed, many studies of school-based mindfulness programmes have reported low adherence to home practice recommendations. Home practice recommendations also create equity issues, as many students may find it difficult to make the time for home mindfulness practice, a factor that is more likely to affect students who are disadvantaged. As such, we argue in this article that research needs to test whether school-based mindfulness programmes that make mindfulness practice time available in the school day result in higher adherence to mindfulness practice recommendations, and whether these programmes are effective at improving student mental health. Unfortunately, very little research has examined how much mindfulness practice is required to obtain meaningful effects. We summarise the small volume of mindfulness dose-response literature to provide guidelines for how much school-based mindfulness practice might be sufficient and provide suggestions for further testing. While making mindfulness practice time available in the school day may be difficult to implement, its efficacy is currently untested. Youth mental health remains a critical issue, providing strong justification for testing whether mindfulness practice made available in the school day results in better outcomes, despite the challenges posed in pursuing this research avenue
Determining the fate of selenium in wheat biofortification: an isotopically labelled field trial study
Aims
The principal aim of this research was to quantify retention of a single, realistic Se biofortification application (10 g ha-1) in contrasting soils over two growing seasons utilizing an enriched stable Se isotope (77Se) to discriminate between applied Se and native soil Se.
Methods
Isotopically enriched 77Se (Na2SeO4) was applied (10 g ha-1) to four replicate plots (2 m x 2 m) of winter wheat, on three contrasting soils on the University of Nottingham farm (UK), at early stem extension in May 2012. Labelled 77Se was assayed in soil and crop fractions by ICP-MS.
Results
Topsoil retained a proportion of applied Se at harvest (c. 15 – 31 %) with only minor retention in subsoil (2-4 %), although losses were 37 – 43 %. Further analysis of topsoil 77Se, the following spring, and at second harvest, suggested that labelled Se retained in soil was25 fixed and uptake by a following crop was negligible.
Conclusions
Prolonged biofortification leads to accumulation of Se in soil but the retained Se has very low bioavailability and mobility. The time required to double the soil Se content would be about 500 years. However, reincorporation of cereal straw could provide a residual source of Se for a following crop, depending on timing and management
Diagonally Neighbour Transitive Codes and Frequency Permutation Arrays
Constant composition codes have been proposed as suitable coding schemes to
solve the narrow band and impulse noise problems associated with powerline
communication. In particular, a certain class of constant composition codes
called frequency permutation arrays have been suggested as ideal, in some
sense, for these purposes. In this paper we characterise a family of neighbour
transitive codes in Hamming graphs in which frequency permutation arrays play a
central rode. We also classify all the permutation codes generated by groups in
this family
Seasonal increases in fish trophic niche plasticity within a flood-pulse river ecosystem (Tonle Sap Lake, Cambodia)
Species' responses to seasonal environmental variation can influence trophic interactions and food web structure within an ecosystem. However, our ability to predict how species' interactions will vary spatially and temporally in response to seasonal variation unfortunately remains inadequate within most ecosystems. Fish assemblages in the Tonle Sap Lake (TSL) of Cambodia-a dynamic flood-pulse ecosystem-were studied for five years (2010-2014) using stable isotope and Bayesian statistical approaches to explore both within-and among-species isotopic niche variation associated with seasonal flooding. Roughly 600 individual fish specimens were collected during 19 sampling events within the lake. We found that fishes within the same species tended to have a broader isotopic niche during the wet season, likely reflecting assimilation of resources from either a wider range of isotopically distinct prey items or a variety of habitats, or both. Furthermore, among-species isotopic niches tended to overlap and range more broadly during the wet season, suggesting that floodplain inundation promotes exploitation of more diverse and similar resources by different species in the fish community. Our study highlights that the flood-pulse dynamic that is typical of tropical aquatic ecosystems may be an essential element supporting freshwater fish community structure and the fish diversity that underpins the TSL food web. This flow regime is currently threatened by regional dam development, which may in turn impact the natural function and structure of the fishery food web
B_s->D_s/B->D Semileptonic Form-Factor Ratios and Their Application to BR(B^0_s->\mu^+\mu^-)
We calculate form-factor ratios between the semileptonic decays
\bar{B}->D^+\ell^-\bar{\nu} and \bar{B}_s->D_s^+\ell^-\bar{\nu} with lattice
QCD. These ratios are a key theoretical input in a new strategy to determine
the fragmentation fractions of the neutral B decays, which are needed for
measurements of BR(B^0_s-> \mu^+\mu^-). We use the MILC ensembles of gauge
configurations with 2+1 flavors of sea quarks at two lattice spacings of
approximately 0.12 fm and 0.09 fm. We use the model-independent
z-parametrization to extrapolate our simulation results at small recoil toward
maximum recoil. Our results for the form-factor ratios are
and
. In
contrast to a QCD sum-rule calculation, no significant departure from U-spin
(ds) symmetry is observed.Comment: 30 pages, 11 figures. Fig. 1 updated. Table II added. Conforms with
version published in Physical Review D, except typos fixed, as in the PRD
Erratum, in Table V (previously Table IV in arXiv v1). Results unchange
Refining new-physics searches in B -> D tau nu decay with lattice QCD
The semileptonic decay channel B -> D tau nu is sensitive to the presence of
a scalar current, such as that mediated by a charged-Higgs boson. Recently the
BaBar experiment reported the first observation of the exclusive semileptonic
decay B -> D tau nu, finding an approximately 2-sigma disagreement with the
Standard-Model prediction for the ratio R(D)=BR(B->D tau nu)/BR(B->D l nu),
where l=e,mu. We compute this ratio of branching fractions using hadronic form
factors computed in unquenched lattice QCD and obtain R(D) = 0.316(12)(7),
where the errors are statistical and total systematic, respectively. This
result is the first Standard-Model calculation of R(D) from ab initio full QCD.
Its error is smaller than that of previous estimates, primarily due to the
reduced uncertainty in the scalar form factor f_0(q^2). Our determination of
R(D) is approximately 1-sigma higher than previous estimates and, thus, reduces
the tension with experiment. We also compute R(D) in models with electrically
charged scalar exchange, such as the type II two-Higgs doublet model. Once
again, our result is consistent with, but approximately 1-sigma higher than,
previous estimates for phenomenologically relevant values of the scalar
coupling in the type II model. As a byproduct of our calculation, we also
present the Standard-Model prediction for the longitudinal polarization ratio
P_L (D)= 0.325(4)(3).Comment: 6 pages, 3 figures, 1 table. References and text added. Fig. 3 R(D)
in 2HDM II corrected and conclusions modified. Standard-Model R(D) unchange
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