721 research outputs found
Large-scale deployment of grass in crop rotations as a multifunctional climate mitigation strategy
The agriculture sector can contribute to climate change mitigation by reducing its own greenhouse gas (GHG) emissions, sequestering carbon in vegetation and soils, and providing biomass to substitute for fossil fuels and other GHG-intensive products. The sector also needs to address water, soil, and biodiversity impacts caused by historic and current practices. Emerging EU policies create incentives for cultivation of perennial plants that provide biomass along with environmental benefits. One such option, common in northern Europe, is to include grass in rotations with annual crops to provide biomass while remediating soil organic carbon (SOC) losses and other environmental impacts. Here, we apply a spatially explicit model on >81,000 sub-watersheds in EU27 + UK (Europe) to explore the effects of widespread deployment of such systems. Based on current accumulated SOC losses in individual sub-watersheds, the model identifies and quantifies suitable areas for increased grass cultivation and corresponding biomass- and protein supply, SOC sequestration, and reductions in nitrogen emissions to water as well as wind and water erosion. The model also provides information about possible flood mitigation. The results indicate a substantial climate mitigation potential, with combined annual GHG savings from soil-carbon sequestration and displacement of natural gas with biogas from grass-based biorefineries, equivalent to 13%–48% of current GHG emissions from agriculture in Europe. The environmental co-benefits are also notable, in some cases exceeding the estimated mitigation needs. Yield increases for annual crops in modified rotations mitigate the displacement effect of increasing grass cultivation. If the grass is used as feedstock in lieu of annual crops, the displacement effect can\ua0even be negative, that is, a reduced need for annual crop production elsewhere. Incentivizing widespread deployment will require supportive policy measures as well as new uses of grass biomass, for example, as feedstock for green biorefineries producing protein concentrate, biofuels, and other bio-based products
A mixed methods approach to advance the understanding of physical activity behaviour during pregnancy
An active pregnancy encompasses benefits that apply to both mother and baby. However, before investing resources in interventions aimed at changing or supporting expectant mothers’ physical activity behaviours, it is necessary to have a greater fundamental understanding of the modifiable factors influencing women’s decisions during this time. Therefore, the main purpose of this study was to investigate the socio-cognitive determinants of physical activity during pregnancy.
A mixed methods research approach using a multiphase design framed by the Theory of Planned Behaviour (TPB; Ajzen, 1991, Organizational Behavior and Human Decision Processes, 50, 179-211) guided the investigation.
Following ethical approval and permission to carry out the study, participants were recruited from randomly selected antenatal clinics in the East Kent region of England. Application of the TPB required both qualitative and quantitative cross-sectional data to be collected. Study One (n = 18) involved the elicitation of pregnant women’s beliefs towards being physically active. The modal salient behavioural, normative and control beliefs were used to inform the development of a TPB questionnaire which was implemented during the next phase of the investigation. Study Two (n = 78) examined the predictive utility of the TPB in explaining pregnant women’s physical activity intentions and behaviour and scrutinised the role of past behaviour within this context.
Finally, Study Three (n = 10) comprised semi-structured interviews involving community midwives. Meta-inferences maintained the function of improving the validity of the study and advancing the overall aim of the research project. Specifically, triangulation was used to ascertain convergence, corroboration, and correspondence
of findings between studies. Whilst results of the individual studies hold merit, meta-inferences point towards the development of three main themes: (1) pregnant women lack access to the necessary information that would allow them to make informed decisions regarding their engagement in physical activities; (2) a co-ordinated effort involving interprofessional collaboration is required to support pregnant women in overcoming barriers associated with regular physical activity participation; and (3) profiling pregnant women according to motivation and behaviour status could serve as a useful and manageable starting point for intervening to produce positive changes in pregnant women’s physical activity behaviour. In normalising physical activity during pregnancy and achieving better health outcomes for mothers and babies, it is necessary to consider the modifiable factors involved in behaviour change, identify opportune moments to intervene, and involve a network of professionals in facilitating and supporting pregnant women’s engagement with physical activities
Flow field visualization of entangled polybutadiene solutions under nonlinear viscoelastic flow conditions
Using self-designed particle visualization instrumentation, startup shear and step-strain tests were conducted under a series of systematically varied rheological and geometrical conditions, and the velocity profiles in three different well-entangled polybutadiene/oligomer solutions were obtained. For startup shear tests, in the regime of entanglement densities up to 89 and nominal reptation Weissenberg numbers up to 18.6, we generally observe either wall slip and a linear velocity/strain profile or simply the linear profile with no wall slip unless a massive edge fracture or instability has occurred in the sample. Meanwhile, step-strain tests conducted at similar and higher step Weissenberg numbers revealed little particle motion upon cessation. These results lead us to a conclusion that there is no compelling evidence of shear banding or nonquiescent relaxation in the range of entanglement density and Wi investigated; we interpret the results to imply that any observed banding probably correlates with edge effects.National Science Foundation (U.S.) (Grant DMR-0934305
Parental Quality of Life and Involvement in Intervention for Children or Adolescents with Autism Spectrum Disorders: A Systematic Review
Previous research has examined several parental, child-related, and contextual factors associated with parental quality of life (QoL) among parents with a child or an adolescent with autism spectrum disorders (ASD); however, no systematic review has examined the relationship between parental QoL and parental involvement in intervention. To fill this gap, a systematic review was conducted using four electronic databases and checked reference lists of retrieved studies. Records were included in the systematic review if they presented original data, assessed parental QoL, and involvement in intervention for children or adolescents with ASD, were published in peer-reviewed journals between 2000 and 2020, and were written in English. Among the 96 screened full-texts, 17 articles met the eligibility criteria. The selected studies included over 2000 parents of children or adolescents with ASD. Three categories of parental involvement (i.e., none, indirect, direct) were identified, which varied across studies, although most had direct parental involvement. The results from this review show that increased parental involvement in the intervention for children or adolescents with ASD may be one way to promote their QoL. However, further research specifically focused on parental involvement during the intervention for children and adolescents with ASD is warranted
Low-energy peak structure in strong-field ionization by mid-infrared laser-pulses: two-dimensional focusing by the atomic potential
We analyze the formation of the low-energy structure (LES) in above-threshold
ionization spectra first observed by Quan et al.\ \cite{quan09} and Blaga et
al.\ \cite{blaga09} using both quasi-classical and quantum approaches. We show
this structure to be largely classical in origin resulting from a
two-dimensional focusing in the energy-angular momentum plane of the
strong-field dynamics in the presence of the atomic potential. The peak at low
energy is strongly correlated with high angular momenta of the photoelectrons.
Quantum simulations confirm this scenario. Resulting parameter dependences
agree with experimental findings \cite{quan09,blaga09} and, in part, with other
simulations \cite{liu10,yan10,kast11}.Comment: 12 pages, 6 figure
Describing and prescribing the constitutive response of yield stress fluids using large amplitude oscillatory shear stress (LAOStress)
Large amplitude oscillatory shear (LAOS) is used as a tool to probe the nonlinear rheological response of a model elasto-viscoplastic material (a Carbopol microgel). In contrast to most recent studies, these large amplitude measurements are carried out in a stress-controlled manner. We outline a descriptive framework of characterization measures for nonlinear rheology under stress-controlled LAOS, and this is contrasted experimentally to the strain-controlled framework that is more commonly used. We show that this stress-controlled methodology allows for a physically intuitive interpretation of the yielding behavior of elasto-viscoplastic materials. The insight gained into the material behavior through these nonlinear measures is then used to develop two constitutive models that prescribe the rheological response of the Carbopol microgel. We show that these two successively more sophisticated constitutive models, which are based on the idea of strain decomposition, capture in a compact manner the important features of the nonlinear rheology of the microgel. The second constitutive model, which incorporates the concept of kinematic hardening, embodies all of the essential behaviors exhibited by Carbopol. These include elasto-viscoplastic creep and time-dependent viscosity plateaus below a critical stress, a viscosity bifurcation at the critical stress, and Herschel–Bulkley flow behavior at large stresses
Resonant Structures in the Low-Energy Electron Continuum for Single Ionization of Atoms in the Tunneling Regime
We present results of high-resolution experiments on single ionization of He,
Ne and Ar by ultra-short (25 fs, 6 fs) 795 nm laser pulses at intensities
0.15-2.0x10^15 W/cm^2. We show that the ATI-like pattern can survive deep in
the tunneling regime and that the atomic structure plays an important role in
the formation of the low-energy photoelectron spectra even at high intensities.
The absence of ponderomotive shifts, the splitting of the peaks and their
degeneration for few-cycle pulses indicate that the observed structures
originate from a resonant process.Comment: 11 pages, 3 figure
Improving Fission-product Decay Data for Reactor Applications: Part I -- Decay Heat
Effort has been expended to assess the relative merits of undertaking further
decay-data measurements of the main fission-product contributors to the decay
heat of neutron-irradiated fissile fuel and related actinides by means of Total
Absorption Gamma-ray Spectroscopy (TAGS/TAS) and Discrete Gamma-ray
Spectroscopy (DGS). This review has been carried out following similar work
performed under the auspices of OECD/WPEC-Subgroup 25 (2005-2007) and the
International Atomic Energy Agency (2010, 2014), and various highly relevant
TAGS measurements completed as a consequence of such assessments. We present
our recommendations for new decay-data evaluations, along with possible
requirements for total absorption and discrete high-resolution gamma-ray
spectroscopy studies that cover approximately 120 fission products and various
isomeric states.Comment: Submitted to European Physical Journal
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