946 research outputs found
Alien Registration- Gillingham, Arthur D. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/31389/thumbnail.jp
Alien Registration- Gillingham, Arthur D. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/31389/thumbnail.jp
Alien Registration- Gillingham, A D. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/32094/thumbnail.jp
Reflexivity: a concept and its meanings for practitioners working with children and families
Reflexivity is a concept that is increasingly gaining currency in professional practice literature, particularly in relation to working with uncertainty and as an important feature of professional discretion and ethical practice. This article discusses how practitioners working in child and family welfare/protection organisations understood and interpreted the concept of reflexivity for their practice, as one of the outcomes of larger, collaborative research project. This project was conducted through a series of workshops with practitioners. The overall research that aimed to expand practitioners’ practice repertoires from narrowly-defined risk assessment, to an approach that could account for the uncertainties of practice, included the concept of reflexivity as an alternative or a complement to instrumental accountability that is increasingly a feature in child welfare/protection organisations. This article discusses how the concept of reflexivity was explored in the research and how practitioners interpreted the concept for their practice. We conclude that while concepts like reflexivity are central to formal theories for professional practice, we also recognise that individual practitioners interpret concepts (in ways that are both practically and contextually relevant), thus creating practical meanings appropriate to their practice contexts.<br /
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
Modeling Uncertainty in Climate Change: A MultiâModel Comparison
The economics of climate change involves a vast array of uncertainties, complicating both the analysis and development of climate policy. This study presents the results of the ïŹrst comprehensive study of uncertainty in climate change using multiple integrated assessment models. The study looks at model and parametric uncertainties for population, total factor productivity, and climate sensitivity. It estimates the pdfs of key output variables, including CO 2 concentrations, temperature, damages, and the social cost of carbon (SCC). One key ïŹnding is that parametric uncertainty is more important than uncertainty in model structure. Our resulting pdfs also provide insights on tail events
Astronomical Seeing from the Summits of the Antarctic Plateau
From the South Pole, microthermal turbulence within a narrow surface boundary
layer some 200m thick provides the dominant contribution to the astronomical
seeing. We present results for the seeing at a wavelength of 2.4um. The narrow
turbulence layer above the site, confined close to the surface, provides
greatly superior conditions for adaptive optics correction than do temperate
latitude sites. An analysis of the available meteorological data for the
Antarctic plateau suggests that sites on its summit, such as Domes A and C,
probably experience significantly better boundary layer seeing than does the
South Pole. In addition, the inversion layers may be significantly narrower,
lending the sites even further to adaptive optics correction than does the
Pole.Comment: 9 pages, including 2 figures. Accepted for publication in Astronomy &
Astrophysics, 200
Modeling Uncertainty in Climate Change: A Multi-Model Comparison
The economics of climate change involves a vast array of uncertainties, complicating both the analysis and development of climate policy. This study presents the results of the first comprehensive study of uncertainty in climate change using multiple integrated assessment models. The study looks at model and parametric uncertainties for population, total factor productivity, and climate sensitivity. It estimates the pdfs of key output variables, including CO2 concentrations, temperature, damages, and the social cost of carbon (SCC). One key finding is that parametric uncertainty is more important than uncertainty in model structure. Our resulting pdfs also provide insights on tail events
Statistical Basis for Predicting Technological Progress
Forecasting technological progress is of great interest to engineers, policy
makers, and private investors. Several models have been proposed for predicting
technological improvement, but how well do these models perform? An early
hypothesis made by Theodore Wright in 1936 is that cost decreases as a power
law of cumulative production. An alternative hypothesis is Moore's law, which
can be generalized to say that technologies improve exponentially with time.
Other alternatives were proposed by Goddard, Sinclair et al., and Nordhaus.
These hypotheses have not previously been rigorously tested. Using a new
database on the cost and production of 62 different technologies, which is the
most expansive of its kind, we test the ability of six different postulated
laws to predict future costs. Our approach involves hindcasting and developing
a statistical model to rank the performance of the postulated laws. Wright's
law produces the best forecasts, but Moore's law is not far behind. We discover
a previously unobserved regularity that production tends to increase
exponentially. A combination of an exponential decrease in cost and an
exponential increase in production would make Moore's law and Wright's law
indistinguishable, as originally pointed out by Sahal. We show for the first
time that these regularities are observed in data to such a degree that the
performance of these two laws is nearly tied. Our results show that
technological progress is forecastable, with the square root of the logarithmic
error growing linearly with the forecasting horizon at a typical rate of 2.5%
per year. These results have implications for theories of technological change,
and assessments of candidate technologies and policies for climate change
mitigation
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