Some of my students are prisoners : issues and dilemmas for social work educators

Higher education recruitment principles and procedures which seek to redress social exclusion have inadvertently resulted in the authors discovering that some of their students are incarcerated. Notwithstanding the important logistical issues which may emerge as a consequence of accepting prisoners into a programme of social work education, it would seem that the inclusion of prisoners is symbolic of a fundamental difference in philosophy with a risk management stance which expects that social work educators act as gatekeepers to the profession, especially in respect of students with criminal convictions. <br /

Energy Efficiency Policies: A Retrospective Examination

We review literature on several types of energy efficiency policies: appliance standards, financial incentive programs, information and voluntary programs, and management of government energy use. For each, we provide a brief synopsis of the relevant programs, along with available existing estimates of energy savings, costs, and cost-effectiveness at a national level. The literature examining these estimates points to potential issues in determining the energy savings and costs, but recent evidence suggests that techniques for measuring both have improved. Taken together, the literature identifies up to four quads of energy savings annually from these programs - at least half of which is attributable to appliance standards and utility-based demand-side management, with possible additional energy savings from the U.S. Department of Energy's (DOE's) ENERGY STAR, Climate Challenge, and Section 1605b voluntary programs to reduce carbon dioxide (CO 2) emissions. Related reductions in CO 2 and criteria air pollutants may contribute an additional 10% to the value of energy savings above the price of energy itself. Copyright © 2006 by Annual Reviews. All rights reserved

PILOT: design and capabilities

The proposed design for PILOT is a general-purpose, wide-field 1 degree 2.4m, f/10 Ritchey-Chretien telescope, with fast tip-tilt guiding, for use 0.5-25 microns. The design allows both wide-field and diffraction-limited use at these wavelengths. The expected overall image quality, including median seeing, is 0.28-0.3" FWHM from 0.8-2.4 microns. Point source sensitivities are estimated.Comment: 4 pages, Proceedings of 2nd ARENA conference 'The Astrophysical Science Cases at Dome C', Potsdam, 17-21 September 200

The historic peat record: Implications for the restoration of blanket bog.

Peaty soils such as those found in blanket bogs lay down a history of their vegetation composition, along with the relative humification of these remains, which can be used to reconstruct bog surface wetness. These records highlight the variability of vegetation cover over time at blanket bog sites and could therefore be used to provide context to inform targets for the outcome of any restoration work. Because the vegetation present currently or in the recent past on the surface of a bog might be due to a relatively recent change, a longer-term history would give a different baseline to aim for. This should be relatively easy to achieve at some level for sites that have had cores taken, for which a database already exists. Historical records show a general picture of natural cycles in peat wetness and vegetation cover, and highlight a large level of variability that is sometimes found over even quite small areas in the timing of peat initiation and the types of vegetation present. This local variability suggests that topography (which varies more within a small spatial extent than climate or edaphic conditions) is a strong determinant of peat growth. However, climatic factors are also important. At some sites, past recovery of Sphagnum has been associated with wetter, cooler phases in the climate. Because rainfall and temperature are likely to change in future with continued climatic change, reconstructed climatic conditions at blanket peat sites could be used to determine whether the projected future climatic conditions at a potential restoration site are likely to fall within the range that supported peat formation in the past. This would help determine whether any restoration work has a chance of succeeding in the long term, and a database of sediment cores has been assembled for England that could be used as a starting point for this. One potential management strategy would be to accept that some vegetation that is currently considered undesirable has been present on blanket bogs in the past, and allow enough time and space for natural cycles to occur. However, what is not known is how much space would be needed to allow such natural cycles to continue, which sites are undergoing change as part of a natural cycle and which are not, or whether these natural cycles might be expected to continue in the same way in the future under climate change. There is some evidence for human impacts on blanket bogs in the past; the use of marginal lands for grazing and agriculture appear to have stopped the spread of peat in some areas, and in some other areas deforestation by humans appears to have been instrumental in initiating peat production. This demonstrates that there is considerable potential for management actions to impact the character of blanket bogs – based on inductive reasoning it seems likely that the reversal of some negative factors (such as blocking drains and removing plantation forestry) will result in the restoration of hydrological function, which could drive further changes in vegetation away from dry heath and trees to Sphagnum-dominated blanket bog that actively forms peat. However, care should be taken when choosing species to re-vegetate bare peat, since Calluna is associated with drier areas. What is not currently known is whether this is a cause or effect of drier conditions, but it is possible that the introduction of Calluna to the bog surface might result in drying of the peat, which would slow the rate of peat formation. Sphagnum is associated with lower emissions of methane and is a main peat forming species, so its suitability for re-vegetating bare peat is likely to be higher if it can become established. The timing of the initiation of erosion at some sites is well before the nitrogen deposition that is often implicated in this, and erosion has not always been caused by human activity. Indeed, some bogs have switched between erosion and accumulation over time, and others have recovered naturally from human impacts. However, what makes some bogs more resilient than others or causes the switch between erosion and accumulation is not known, and further research here would be beneficial to inform restoration management

Food Dispersion and Foraging Energetics: a Mechanistic Synthesis for Field Studies of Avian Benthivores

Much effort has focused on modeling and measuring the energy costs of free existence and the foraging strategies of animals. However, few studies have quantitatively linked these approaches to the patch structure of foods in the field. We developed an individual—based model that relates field measurements of the dispersion of benthic foods to search costs and foraging profitability of diving ducks. On Lake Mattamuskeet, North Carolina, Canvasback ducks (Aythya valisineria) eat only the belowground winter buds of the submerged plant Vallisneria americana. We measured and modeled the patch structure of winter buds at the level of potential foraging loci, defined as contiguous circles 1 m in diameter. In the field and in the model, Canvasbacks make repeated vertical dives in such loci, foraging in the sediments by touch, before surface—swimming to another locus. We quantified first—order patchiness by fitting a negative binomial distribution to core samples taken at 50-m intervals along transects, to yield the frequencies of loci with different bud densities. Second-order patchiness was measured by taking cores at 1-m increments radiating from each sampling point, and regressing bud density at each sampling point on densities at these increments. No significant correlations were found, indicating that Canvasbacks could not predict food densities based on densities in nearby foraging loci. For the model, we generated food grids from the negative binomial distributions of core samples. Energy costs of diving were calculated by applying aerobic efficiencies (mechanical power output / aerobic power input) to biomechanical models. Unlike respirometry alone, this method accounts for effects on dive costs of varying water depth and dive duration. We used measurements of Canvasback intake rates at different bud densities to calculate profitability (energy intake minus expenditure) for each dive. Multivariate uncertainty analyses (Latin hypercube) indicated that profitability for Canvasbacks foraging on Vallisneria buds is determined mainly by food—item size and locomotor costs of descent. Bud metabolizable energy, water temperature, bud dispersion, and search and handling time coefficients of the functional response for intake rate have relatively minor influence. Individual-parameter perturbations indicated that to maintain the same foraging benefits, the total area of Vallisneria habitat would have to increase by 1.4-fold if dry mass per bud decreased from 0.10 to 0.03 g, and by 2.1-fold if water depth increased from 0.5 to 2 m. Our method allows study of interactions between patch structure and foraging energetics without detailed spatial mapping of foods, which is not feasible at appropriate scales for highly mobile benthivores. The model yields estimates of energy balance, contaminant intake, and amount and quality of foraging habitat required to sustain diving duck populations under varying environmental conditions. More accurate prediction of giving-up times and giving-up food densities will require better understanding of the time scale over which ducks balance their energy budgets

Statistical analysis of Ni nanowires breaking processes: a numerical simulation study

A statistical analysis of the breaking behavior of Ni nanowires is presented. Using molecular dynamic simulations, we have determined the time evolution of both the nanowire atomic structure and its minimum cross section (Sm(t)). Accumulating thousands of independent breaking events, Sm histograms are built and used to study the influence of the temperature, the crystalline stretching direction and the initial nanowire size. The proportion of monomers, dimers and more complex structures at the latest stages of the breaking process are calculated, finding important differences among results obtained for different nanowire orientations and sizes. Three main cases have been observed. (A) [111] stretching direction and large nanowire sizes: the wire evolves from more complex structures to monomers and dimers prior its rupture; well ordered structures is presented during the breaking process. (B) Large nanowires stretched along the [100] and [110] directions: the system mainly breaks from complex structures (low probability of finding monomers and dimers), having disordered regions during their breakage; at room temperature, a huge histogram peak around Sm=5 appears, showing the presence of long staggered pentagonal Ni wires with ...-5-1-5-... structure. (C) Initial wire size is small: strong size effects independently on the temperature and stretching direction. Finally, the local structure around monomers and dimmers do not depend on the stretching direction. These configurations differ from those usually chosen in static studies of conductance.Comment: 18 pages, 13 figure