Subsurface compaction a guide for WA farmers and consultants

For plants to grow in agricultural soils, roots and emerging shoots must be able to force their way through the soil. In soils of high strength, this growth is physically restricted. High strength soils may be due to natural soil characteristics and conditions or develop as a result of agricultural practices and may be in layers or throughout the soil profile. In agriculture, high strength soils commonly occur as a result of compaction. Compaction of agricultural soils can be in the surface (often caused by stock trampling or rain drop splatter) or in the subsurface (usually in a layer at 10–40 cm). Subsurface compaction has a different suite of effects and management options than surface compaction, although, subsurface compaction amelioration techniques may also benefit a hardsetting profile. Subsurface compaction can occur in most Western Australian agricultural soils. Some soils have greater capacity to resist compaction or to self-repair following compaction. However, nearly three-quarters of WA’s agricultural soils are either affected by, or highly susceptible to, subsurface compaction (Figure 1). Compacted subsurface soil restricts crop and pasture root growth with plant biomass correspondingly reduced. In most seasons this also results in grain yield reduction. The average opportunity cost of lost agricultural production is estimated at $333 million per year for the Northern, Central, Southern and South West Agricultural regions (Herbert 2009). The most common forms of subsurface compaction in WA agricultural soils are traffic and plough hardpans caused by agricultural equipment and are the focus of this guide. In most cases these hardpans can be economically remedied and appropriate agricultural practice can minimise the reformation of hardpans.https://researchlibrary.agric.wa.gov.au/bulletins/1206/thumbnail.jp

Variations on the Theme of Journe's Lemma

Journe's Lemma is a critical component of many questions related to the product ${BMO}$ theory of S.-Y. Chang and R. Fefferman. This article presents several different variants of the Lemma, some known, some implicit in the literature, and some new.Comment: 27 pages ; 17 references; To appear in Houston Journal of Mathematic

Global Properties of the Globular Cluster Systems of Four Spiral Galaxies

We present results from a wide-field imaging study of the globular cluster (GC) systems of a sample of edge-on, Sb-Sc spiral galaxies ~7-20 Mpc away. This study is part of a larger survey of the ensemble properties of the GC populations of giant galaxies. We imaged the galaxies in BVR filters with large-format CCD detectors on the WIYN 3.5-m telescope, to projected radii of ~20-40 kpc. For four galaxies (NGC 2683, NGC 3556, NGC 4157, and NGC 7331), we quantify the radial distributions of the GC systems and estimate the total number, luminosity- and mass-normalized specific frequencies (S_N and T), and blue (metal-poor) fraction of GCs. A fifth galaxy (NGC 3044) was apparently too distant for us to have detected its GC system. Our S_N for NGC 2683 is 2.5 times smaller than the previously-published value, likely due in part to reduced contamination from non-GCs. For the spiral galaxies analyzed for the survey to date, the average number of GCs is 170+/-40 and the weighted mean values of S_N and T are 0.8+/-0.2 and 1.4+/-0.3. We use the survey data to derive a relationship between radial exent of the GC system and host galaxy mass over a factor of 20 in mass. Finally, we confirm the trend, identified in previous survey papers, of increasing specific frequency of metal-poor GCs with increasing galaxy mass. We compare the data with predictions from a simple model and show that carefully quantifying the numbers of metal-poor GCs in galaxies can constrain the formation redshifts of the GCs and their host galaxies.Comment: 30 pages, including 14 figures and 13 tables; accepted for publication in The Astronomical Journal, Oct 2007 issu

Early 18th Century Hand Grenades on the North American Atlantic Coast: An Experimental Archaeology Study

In the first half of the eighteenth century, standardization of weapons appears in cannon, shot, and small arms. No comparative study has been conducted to determine if grenades follow this pattern. In this study, three collections of cast iron grenades dating from 1700-1750 were compared to determine if any statistical significance exists. If so, this will form the basis to create a taxonomy to assist in dating sites. Furthermore, grenade blasts from this era are reported in the historical record but recorders barely understood ballistics. An experimental phase has been designed into the project to fully record a blast via controlled detonation. The concussive force and decibel levels were recorded to help assess potential damage. Upon completion, medical evaluations can be made to determine the full lethality of cast iron grenades. This allows an evaluation of historical records for unexplained deaths, altered behaviors post battle, and critical evaluation of historical documents on grenade lethality

Jim Allen : radical drama beyond 'days of hope'

Due to a desire to establish television as a serious medium, television drama has often been seen as a forum for writers, with names such as David Mercer, Dennis Potter and Trevor Griffiths identified by critics as the driving force, or auteur, behind the works that bear their names rather than, as in much writing about film, the director. However, while this has been so, there are also many examples of writers whose contribution to television writing has been much less celebrated, often due to their close collaboration with a high-profile director who in many critics’ view remains the most influential contributor to the final piece of work. One practitioner who arguably has failed to get the critical credit he is due is Jim Allen, a writer still perhaps best known for his work with one such high-profile director, Ken Loach

Assessing the Effectiveness of a Bedtime Behavioral Intervention for Military Children with a Deployed Parent

While there are advantages and disadvantages to the lifestyle of a military family, challenges often include frequent moves, stressful military work environments, and deployments of the active duty member to dangerous war zones. Military children often display an array of internalizing and externalizing problems, with one common problem being disrupted sleep. The purpose of the current study was to evaluate the use of current technology to minimize problematic sleep behaviors affecting young children with a recently deployed parent. The intervention required parents to show their child a previously recorded DVD of the deployed parent reading a children’s book prior to the child’s bedtime. Sleep diary data were collected for two children who had been previously identified as having significant bedtime resistant behavior. A nonconcurrent, multiple-baselines across participants research design was used to evaluate data with two data collection phases for both participants. Analyses revealed considerable reductions in the number of bedtime resistant behaviors post-intervention and large effect sizes were yielded for the intervention phases for both participants. Implications for clinical practice are discussed

Cellular-level versus receptor-level response threshold hierarchies in T-Cell activation

Peptide-MHC (pMHC) ligand engagement by T-cell receptors (TCRs) elicits a variety of cellular responses, some of which require substantially more TCR-mediated stimulation than others. This threshold hierarchy could reside at the receptor level, where different response pathways branch off at different stages of the TCR/CD3 triggering cascade, or at the cellular level, where the cumulative TCR signal registered by the T-cell is compared to different threshold values. Alternatively, dual-level thresholds could exist. In this study, we show that the cellular hypothesis provides the most parsimonious explanation consistent with data obtained from an in-depth analysis of distinct functional responses elicited in a clonal T-cell system by a spectrum of biophysically defined altered peptide ligands across a range of concentrations. Further, we derive a mathematical model that describes how ligand density, affinity, and off-rate all affect signaling in distinct ways. However, under the kinetic regime prevailing in the experiments reported here, the TCR/pMHC class I (pMHCI) dissociation rate was found to be the main governing factor. The CD8 coreceptor modulated the TCR/pMHCI interaction and altered peptide ligand potency. Collectively, these findings elucidate the relationship between TCR/pMHCI kinetics and cellular function, thereby providing an integrated mechanistic understanding of T-cell response profiles