3,743 research outputs found
The software-cycle model for re-engineering and reuse
This paper reports on the progress of a study which will contribute to our ability to perform high-level, component-based programming by describing means to obtain useful components, methods for the configuration and integration of those components, and an underlying economic model of the costs and benefits associated with this approach to reuse. One goal of the study is to develop and demonstrate methods to recover reusable components from domain-specific software through a combination of tools, to perform the identification, extraction, and re-engineering of components, and domain experts, to direct the applications of those tools. A second goal of the study is to enable the reuse of those components by identifying techniques for configuring and recombining the re-engineered software. This component-recovery or software-cycle model addresses not only the selection and re-engineering of components, but also their recombination into new programs. Once a model of reuse activities has been developed, the quantification of the costs and benefits of various reuse options will enable the development of an adaptable economic model of reuse, which is the principal goal of the overall study. This paper reports on the conception of the software-cycle model and on several supporting techniques of software recovery, measurement, and reuse which will lead to the development of the desired economic model
Behavioural simulation of biological neuron systems using VHDL and VHDL-AMS
The investigation of neuron structures is an incredibly difficult and complex task that yields relatively low rewards in terms of information from biological forms (either animals or tissue). The structures and connectivity of even the simplest invertebrates are almost impossible to establish with standard laboratory techniques, and even when this is possible it is generally time consuming, complex and expensive. Recent work has shown how a simplified behavioural approach to modelling neurons can allow “virtual” experiments to be carried out that map the behaviour of a simulated structure onto a hypothetical biological one, with correlation of behaviour rather than underlying connectivity. The problems with such approaches are numerous. The first is the difficulty of simulating realistic aggregates efficiently, the second is making sense of the results and finally, it would be helpful to have an implementation that could be synthesised to hardware for acceleration. In this paper we present a VHDL implementation of Neuron models that allow large aggregates to be simulated. The models are demonstrated using a system level VHDL and VHDL-AMS model of the C. Elegans locomotory system
A Quaker Experiment in Town Planning: George Cadbury and the Construction of Bournville Model Village
In 1893, George Cadbury initiated the construction of Bournville Model Village, Birmingham (UK). This was the first model settlement to provide low-density housing not restricted to facto1y employees. This paper examines the relationship between Cadbury\u27s Quaker faith, the growth of his business and the development of a model community. The focus is on exploring the ways in which Cadbury departed from traditional Quaker practices, with respect to visual artistic display and religious intervention in social relations. The article, first, reviews the contribution of Quakerism to the building of George Cadbury\u27s business empire. Second, it examines the relationship between Cadbury\u27s religiously infom1ed brand of benign capitalism and the choice of a particular architectural aesthetic for Bournville. Third, the article shows how evangelical Quaker faith and practice were important in shaping the social development of the Bournville community
THE LACK OF A PROFIT MOTIVE FOR RANCHING: IMPLICATIONS FOR POLICY ANALYSIS
The economic impact of changing land-use policies has traditionally been estimated using the standard economic model of profit maximization. Ranchers are assumed to maximize profit and to adjust production strategies so as to continue maximizing profit with altered policies. Yet, nearly 30 years of research and observation have shown that family, tradition, and the desirable way of life are the most important factors in the ranch purchase decision - not profit. Ranch buyers want an investment they can touch, feel, and enjoy, and they historically have been willing to accept relatively low returns from the livestock production. Profit maximization appears to be an inadequate model for explaining rancher behavior, describing grazing land use, and estimating the impacts of altered public land policies. In this paper, we investigate the relative importance of livestock production income and desirable lifestyle attributes in determining the market value of western ranches, and we explore what this means for economic models and policy analysis.Agricultural and Food Policy, Land Economics/Use,
Calf health and performance during receiving is not changed by fence-line preconditioning on flint hills range vs. drylot preconditioning
Ranch-of-origin preconditioning can improve the welfare and performance of beef
calves by decreasing the stress associated with weaning, transport, diet change, and
commingling with other calves. Preconditioning methods that involve pasture weaning
coupled with maternal contact (i.e., fence-line weaning) have been promoted as possible
best management practices for minimizing stress. Prior studies focused on performance
and behavior during preconditioning on the ranch of origin. Little information has
been published relating to carryover effects of fence-line preconditioning compared
with conventional drylot preconditioning on performance and behavior during feedlot
receiving.
Our objectives were to measure growth and health during a 28-day ranch-of-origin
preconditioning phase and during a 60-day feedlot receiving phase among beef calves
subjected to 1 of 3 ranch-of-origin preconditioning programs: (1) drylot preconditioning
+ dam separation, (2) pasture preconditioning + fence-line contact with dams, and
(3) pasture preconditioning + fence-line contact with dams + supplemental feed delivered
in a bunk. In addition, we recorded incidences of behavioral distress among these
treatments during first 7 days of feedlot receiving
On the spectroastrometric separation of binary point-source fluxes
Spectroastrometry is a technique which has the potential to resolve flux
distributions on scales of milliarcseconds. In this study, we examine the
application of spectroastrometry to binary point sources which are spatially
unresolved due to the observational point spread function convolution. The
technique uses measurements with sub-pixel accuracy of the position centroid of
high signal-to-noise long-slit spectrum observations. With the objects in the
binary contributing fractionally more or less at different wavelengths
(particularly across spectral lines), the variation of the position centroid
with wavelength provides some information on the spatial distribution of the
flux. We examine the width of the flux distribution in the spatial direction,
and present its relation to the ratio of the fluxes of the two components of
the binary. Measurement of three observables (total flux, position centroid and
flux distribution width) at each wavelength allows a unique separation of the
total flux into its component parts even though the angular separation of the
binary is smaller than the observations' point-spread function. This is because
we have three relevant observables for three unknowns (the two fluxes, and the
angular separation of the binary), which therefore generates a closed problem.
This is a wholly different technique than conventional deconvolution methods,
which produce information on angular sizes of the sampling scale.
Spectroastrometry can produce information on smaller scales than conventional
deconvolution, and is successful in separating fluxes in a binary object with a
separation of less than one pixel. We present an analysis of the errors
involved in making binary object spectroastrometric measurements and the
separation method, and highlight necessary observing methodology.Comment: 11 pages, 8 figures, accepted for publication in Astronomy and
Astrophysic
Gait analysis in a <i>Mecp2</i> knockout mouse model of Rett syndrome reveals early-onset and progressive motor deficits
Rett syndrome (RTT) is a genetic disorder characterized by a range of features including cognitive impairment, gait abnormalities and a reduction in purposeful hand skills. Mice harbouring knockout mutations in the <i>Mecp2</i> gene display many RTT-like characteristics and are central to efforts to find novel therapies for the disorder. As hand stereotypies and gait abnormalities constitute major diagnostic criteria in RTT, it is clear that motor and gait-related phenotypes will be of importance in assessing preclinical therapeutic outcomes. We therefore aimed to assess gait properties over the prodromal phase in a functional knockout mouse model of RTT. In male <i>Mecp2</i> knockout mice, we observed alterations in stride, coordination and balance parameters at 4 weeks of age, before the onset of other overt phenotypic changes as revealed by observational scoring. These data suggest that gait measures may be used as a robust and early marker of <i>Mecp2</i>-dysfunction in future preclinical therapeutic studies
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The effects of minimal tillage, contour cultivation and in-field vegetative barriers on soil erosion and phosphorus loss.
Runoff, sediment, total phosphorus and total dissolved phosphorus losses in overland flow were measured for two years on unbounded plots cropped with wheat and oats. Half of the field was cultivated with minimum tillage (shallow tillage with a tine cultivator) and half was conventionally ploughed. Within each cultivation treatment there were different treatment areas (TA). In the first year of the experiment, one TA was cultivated up and down the slope, one TA was cultivated on the contour, with a beetle bank acting as a vegetative barrier partway up the slope, and one had a mixed direction cultivation treatment, with cultivation and drilling conducted up and down the slope and all subsequent operations conducted on the contour. In the second year, this mixed treatment was replaced with contour cultivation. Results showed no significant reduction in runoff, sediment losses or total phosphorus losses from minimum tillage when compared to the conventional plough treatment, but there were increased losses of total dissolved phosphorus with minimum tillage. The mixed direction cultivation treatment increased surface runoff and losses of sediment and phosphorus. Increasing surface roughness with contour cultivation reduced surface runoff compared to up and down slope cultivation in both the plough and minimum tillage treatment areas, but this trend was not significant. Sediment and phosphorus losses in the contour cultivation treatment followed a very similar pattern to runoff. Combining contour cultivation with a vegetative barrier in the form of a beetle bank to reduce slope length resulted in a non-significant reduction in surface runoff, sediment and total phosphorus when compared to up and down-slope cultivation, but there was a clear trend towards reduced losses. However, the addition of a beetle bank did not provide a significant reduction in runoff, sediment losses or total phosphorus losses when compared to contour cultivation, suggesting only a marginal additional benefit. The economic implications for farmers of the different treatment options are investigated in order to assess their suitability for implementation at a field scale
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