Extended grazing: A detailed analysis of Irish dairy farms

Profitability and factors affecting grazing season length were econometrically analyzed using a representative sample of Irish dairy farms. The objective of this study was to explore what potential exists on Irish dairy farms to extend the grazing season and to quantify the possible economic benefits that result from lengthening the grazing season. Regression results indicate that location factors affect the length of the grazing season, but even when physical factors are controlled, farmer characteristics, such as education, also affect the grazing season length. The results of a panel data analysis show that significant cost reductions can be achieved by extending the grazing season. Overall, the findings indicate that lengthening the grazing season offers a cost-saving alternative on many Irish dairy farms, which could contribute to strengthening the competitiveness of the Irish dairy sector

Wavelength- and material-dependent absorption in GaAs and AlGaAs microcavities

The quality factors of modes in nearly identical GaAs and Al_{0.18}Ga_{0.82}As microdisks are tracked over three wavelength ranges centered at 980 nm, 1460 nm, and 1600 nm, with quality factors measured as high as 6.62x10^5 in the 1600-nm band. After accounting for surface scattering, the remaining loss is due to sub-bandgap absorption in the bulk and on the surfaces. We observe the absorption is, on average, 80 percent greater in AlGaAs than in GaAs and in both materials is 540 percent higher at 980 nm than at 1600nm.Comment: 4 pages, 2 figures, 1 table, minor changes to disucssion of Qrad and Urbach tai

Monomer diffusion into static and evolving polymer networks during frontal photopolymerisation

Frontal photopolymerisation (FPP) is a directional solidification process that converts monomer-rich liquid into crosslinked polymer solid by light exposure and finds applications ranging from lithography to 3D printing. Inherent to this process is the creation of an evolving polymer network that is exposed to a monomer bath. A combined theoretical and experimental investigation is performed to determine the conditions under which monomer from this bath can diffuse into the propagating polymer network and cause it to swell. First, the growth and swelling processes are decoupled by immersing pre-made polymer networks into monomer baths held at various temperatures. The experimental measurements of the network thickness are found to be in good agreement with theoretical predictions obtained from a nonlinear poroelastic model. FPP propagation experiments are then carried out under conditions that lead to swelling. Unexpectedly, for a fixed exposure time, swelling is found to increase with incident light intensity. The experimental data is well described by a novel FPP model accounting for mass transport and the mechanical response of the polymer network, providing key insights into how monomer diffusion affects the conversion profile of the polymer solid and the stresses that are generated during its growth. The predictive capability of the model will enable the fabrication of gradient materials with tuned mechanical properties and controlled stress development

Modelling Winter Grass Growth and Senescence

In temperate climates, because net grass growth in winter is low, most grass growth models deal with the main growing season (Mar-Oct in the N Hemisphere), with little emphasis on grass growth in winter (Nov-Feb). However, grass tissue turns over continuously (Hennessy et al., 2004) and the fate of herbage entering the winter is important in extended grazing season systems. This study aimed to model winter grass growth for the period 15 Oct 2001 to 28 Jan 2002 for a range of autumn closing dates (1 Sep, 20 Sep and 10 Oct) by modifying an existing model, so that the amount of green leaf could be predicted at intervals over the winter

Parent-child interactions and objectively measured child physical activity: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Parents influence their children's behaviors directly through specific parenting practices and indirectly through their parenting style. Some practices such as logistical and emotional support have been shown to be positively associated with child physical activity (PA) levels, while for others (e.g. monitoring) the relationship is not clear. The objectives of this study were to determine the relationship between parent's PA-related practices, general parenting style, and children's PA level.</p> <p>Methods</p> <p>During the spring of 2007 a diverse group of 99 parent-child dyads (29% White, 49% Black, 22% Hispanic; 89% mothers) living in low-income rural areas of the US participated in a cross-sectional study. Using validated questionnaires, parents self-reported their parenting style (authoritative, authoritarian, permissive, and uninvolved) and activity-related parenting practices. Height and weight were measured for each dyad and parents reported demographic information. Child PA was measured objectively through accelerometers and expressed as absolute counts and minutes engaged in intensity-specific activity.</p> <p>Results</p> <p>Seventy-six children had valid accelerometer data. Children engaged in 113.4 ± 37.0 min. of moderate-vigorous physical activity (MVPA) per day. Children of <it>permissive </it>parents accumulated more minutes of MVPA than those of <it>uninvolved </it>parents (127.5 vs. 97.1, <it>p </it>< 0.05), while parents who provided above average levels of support had children who participated in more minutes of MVPA (114.2 vs. 98.3, <it>p </it>= 0.03). While controlling for known covariates, an <it>uninvolved </it>parenting style was the only parenting behavior associated with child physical activity. Parenting style moderated the association between two parenting practices - reinforcement and monitoring - and child physical activity. Specifically, post-hoc analyses revealed that for the <it>permissive </it>parenting style group, higher levels of parental reinforcement or monitoring were associated with higher levels of child physical activity.</p> <p>Conclusions</p> <p>This work extends the current literature by demonstrating the potential moderating role of parenting style on the relationship between activity-related parenting practices and children's objectively measured physical activity, while controlling for known covariates. Future studies in this area are warranted and, if confirmed, may help to identify the mechanism by which parents influence their child's physical activity behavior.</p

A review of High Performance Computing foundations for scientists

The increase of existing computational capabilities has made simulation emerge as a third discipline of Science, lying midway between experimental and purely theoretical branches [1, 2]. Simulation enables the evaluation of quantities which otherwise would not be accessible, helps to improve experiments and provides new insights on systems which are analysed [3-6]. Knowing the fundamentals of computation can be very useful for scientists, for it can help them to improve the performance of their theoretical models and simulations. This review includes some technical essentials that can be useful to this end, and it is devised as a complement for researchers whose education is focused on scientific issues and not on technological respects. In this document we attempt to discuss the fundamentals of High Performance Computing (HPC) [7] in a way which is easy to understand without much previous background. We sketch the way standard computers and supercomputers work, as well as discuss distributed computing and discuss essential aspects to take into account when running scientific calculations in computers.Comment: 33 page

On the Short Distance Part of the QCD Anomaly Contribution to the b --> s eta' Amplitude

In addressing the B --> eta' K puzzle, there has been a considerable hope in the literature to resolve it by the QCD anomaly contribution to the b --> s eta' amplitude. This contribution corresponds to the electroweak b --> s g* g* transition followed by the off-shell gluon fusion g* g* --> eta'. In the present paper we perform a critical reassessment of this issue. We show that for the hard virtual gluons in a loop there is a well defined short distance amplitude corresponding to a remnant of the QCD anomaly. However, we find that it cannot account for the measured amplitude. In addition, we point out that the reduction of the gluon fusion vertex for the off-shell gluons is compensated by an absence of the claimed suppression in the electroweak vertex, and that some nonperturbative contributions related to the QCD anomaly may still be viable in explaining the physical B --> eta' K amplitude.Comment: 11 pages, 4 figures, LaTeX + elsart.cls, to appear in Phys. Lett.

A preclinical evaluation of the PI3K alpha/delta dominant inhibitor BAY 80-6946 in HER2-positive breast cancer models with acquired resistance to the HER2-targeted therapies trastuzumab and lapatinib.

The PI3K pathway is a key mechanism of trastuzumab resistance, but early attempts to indirectly target this pathway with mTOR inhibitors have had limited success. We present the results of a preclinical study of the selective alpha/delta isoform dominant PI3K inhibitor BAY 80-6946 tested alone and in combination with HER2-targeted therapies in HER2-positive cell lines, including models with acquired resistance to trastuzumab and/or lapatinib. A panel of HER2-positive breast cancer cells were profiled for their mutational status using Sequenom MassARRAY, PTEN status by Western blot, and anti-proliferative response to BAY 80-6946 alone and in combination with the HER2-targeted therapies trastuzumab, lapatinib and afatinib. Reverse phase protein array was used to determine the effect of BAY 80-6946 on expression and phosphorylation of 68 proteins including members of the PI3K and MAPK pathways. The Boyden chamber method was used to determine if BAY 80-6946 affected cellular invasion and migration. BAY 80-6946 has anti-proliferative and anti-invasive effects when used alone in our panel of cell lines (IC50s 3.9-29.4 nM). BAY 80-6946 inhibited PI3K signalling and was effective in cells regardless of their PI3K, P53 or PTEN status. The combination of HER2-targeted therapies and BAY 80-6946 inhibited growth more effectively than either therapy used alone (with clear synergism in many cases), and can restore sensitivity to trastuzumab and lapatinib in cells with acquired resistance to either trastuzumab and/or lapatinib. The addition of BAY 80-6946 to HER2-targeted therapy could represent an improved treatment strategy for patients with refractory metastatic HER2-positive breast cancer, and should be considered for clinical trial evaluation