998 resultados para Repetitive patterns
Resumo:
The contracting-out of public services has often been accompanied by a strong academic focus on the emergence of new governance forms, and a general neglect of the processes and practices through which contracted-out services are controlled and monitored. To fill this gap, we draw on contracting-out and inter-organizational control literatures to explore the adoption of control mechanisms for public service provision at the municipal level and the variables that can explain their choice. Our results, based on a survey of Italian municipalities, show that in the presence of contracting-out, market-, hierarchy- and trust-based controls display different intensities, can co-exist and are explained by different variables. Service characteristics are more effective in explaining market- and hierarchy-based controls than relationship characteristics. Trust-based controls are the most widespread, but cannot be explained by the variables traditionally identified in contracting-out and inter-organizational control studies.
Resumo:
There is little understanding in ecology as to how biodiversity patterns emerge from the distribution patterns of individual species. Here we consider the question of the contributions of rare (restricted range) and common (widespread) species to richness patterns. Considering a species richness pattern, is most of the spatial structure, in terms of where the peaks and troughs of diversity lie, caused by the common species or the rare species (or neither)? Using southern African and British bird richness patterns, we show here that commoner species are most responsible for richness patterns. While rare and common species show markedly different species richness patterns, most spatial patterning in richness is caused by relatively few, more common, species. The level of redundancy we found suggests that a broad understanding of what determines the majority of spatial variation in biodiversity may be had by considering only a minority of species.
Resumo:
The spatial distribution of a species can be characterized at many different spatial scales, from fine-scale measures of local population density to coarse-scale geographical-range structure. Previous studies have shown a degree of correlation in species' distribution patterns across narrow ranges of scales, making it possible to predict fine-scale properties from coarser-scale distributions. To test the limits of such extrapolation, we have compiled distributional information on 16 species of British plants, at scales ranging across six orders of magnitude in linear resolution (1 in to 100 km). As expected, the correlation between patterns at different spatial scales tends to degrade as the scales become more widely separated. There is, however, an abrupt breakdown in cross-scale correlations across intermediate (ca. 0.5 km) scales, suggesting that local and regional patterns are influenced by essentially non-overlapping sets of processes. The scaling discontinuity may also reflect characteristic scales of human land use in Britain, suggesting a novel method for analysing the 'footprint' of humanity on a landscape.
Resumo:
It is shown theoretically that LEED patterns from ordered overlayer systems bear a strong relationship to electron holograms, and that phase information is recorded in the diffraction intensities. It is, therefore, possible to obtain structural information by direct holographic inversion from conventional LEED I-V spectra.
Resumo:
BARTON 1 has suggested that photoelectron interference patterns may be used directly as holograms to obtain atomic-resolution images of surface structures. Bulk structures have been obtained previously by this means from experimental patterns of high-energy Kikuchi(quasi-elastically scattered) and Auger electrons 2,3. Here we test the feasibility of this technique for determination of surface structures using Auger intensity patterns obtained 4,5 from iodine chemisorbed on a pseudomorphic silver monolayer on Pt{111}. By direct numerical holographic inversion, we obtain three-dimensional images which show that iodine adatoms are located in hollows of 3-fold symmetry on the surface. The images yield the site symmetry with good atomic resolution in the surface plane, but suffer from poor resolution along the Ag-I axis. We anticipate that data with better angular resolution obtained at low temperatures would improve the spatial resolution of such images.
Resumo:
This qualitative study explored disordered eating in a small group of first-year undergraduate students and addresses a gap in the literature by exploring their lived experience.
Aims: To better understand student’s needs in those experiencing or at risk of developing disordered eating during their first year at university and to illustrate what support mechanisms and services are required to better support students experiencing or at risk during their first year at university.
Conclusion: The University could further develop its outreach to new students with a more consistently supportive programme providing better facilities and training for stress appraisal and coping and more support via student buddying. The University could also extend its programme on positive mental health in an attempt to better inform on disordered eating and to reduce a sense of stigma within the student population. Personal tutors and student health care facilities need to be consistently trained in the understanding and person centred approach to students experiencing disordered eating, particularly the sub-clinical group. In addition the University could consider some small changes and adaptations to the refectory eating areas to better facilitate students who may be at risk from disordered eating. Finally the University could perhaps better use the potentially liminal period within the first few months of student's arrival at university (a new beginning) to help embed a program to develop a stronger sense of coherence and well-being.
Resumo:
Policymakers have largely replaced Single Bounded Discrete Choice (SBDC) valuation by the more statistically efficient repetitive methods; Double Bounded Discrete Choice (DBDC) and Discrete Choice Experiments (DCE) . Repetitive valuation permits classification into rational preferences: (i) a priori well-formed; (ii) consistent non-arbitrary values “discovered” through repetition and experience; (Plott, 1996; List 2003) and irrational preferences; (iii) consistent but arbitrary values as “shaped” by preceding bid level (Tufano, 2010; Ariely et al., 2003) and (iv) inconsistent and arbitrary values. Policy valuations should demonstrate behaviorally rational preferences. We outline novel methods for testing this in DBDC applied to renewable energy premiums in Chile.
Resumo:
Fluxes of HCH isomers α- and γ-HCH dynamics were determined in four industrial U.K. rivers feeding the North Sea. Sampling was conducted weekly basis over a 2-year period. This was complemented by discrete studies of events where two hourly sampling periods were used to investigate the fine time scale dynamics of fluxes. Two intensively industrialized rivers had average isomer concentrations of ~20 ng L-1 for both isomers, while average concentrations in the two less industrialized rivers ranged between 1.5 and 5.0 ng L-1. α-HCH concentrations showed no strong temporal patterns on any river, which contrasts with γ-HCH levels that increased considerably during late summer/early autumn following sustained periods of low river flow. Sampling during high river flow events on rivers with differing HCH pollution histories both showed the same dynamics in HCH isomer concentrations. γ-HCH concentrations decreased 4-fold during events while α-HCH-concentrations stayed constant. The increases in γ-HCH concentrations under low flow conditions and the rapid dilution of this isomer during events indicate that γ-HCH has current inputs to these river systems. It was calculated that these four rivers export 30.8 kg yr-1 of γ-HCH and 14.8 kg yr-1 of α-HCH to the North Sea.
Resumo:
Hematopoietic chimerism was analyzed in serial bone marrow samples taken from 28 children following T-cell depleted unrelated donor bone marrow transplants (UD BMT) for acute lymphoblastic leukemia (ALL). Chimeric status was determined by polymerase chain reaction (PCR) of simple tandem repeat (STR) sequences (maximal sensitivity, 0.1%). At least two serial samples were examined in 23 patients. Of these, two had evidence of complete donor engraftment at all times and eight showed stable low level mixed chimerism (MC) (<1% recipient hematopoiesis). All 10 of these patients remain in remission with a minimum follow-up of 24 months. By contrast, 13 patients demonstrated a progressive return of recipient hematopoiesis. Five of these relapsed (4 to 9 months post BMT), one died of cytomegalovirus pneumonitis and seven remain in remission with a minimum follow-up of 24 months. Five children were excluded from serial analysis as two serial samples were not collected before either relapse (3) or graft rejection (2). We conclude that as with sibling transplants, ex vivo T depleted UD BMT in children with ALL is associated with a high incidence of MC. Stable donor engraftment and low level MC always correlated with continued remission. However, detection of a progressive return of recipient cells did not universally correlate with relapse, but highlighted those patients at greatest risk. Serial chimerism analysis by PCR of STRs provides a rapid and simple screening technique for the detection of relapse and the identification of patients with progressive MC who might benefit from detailed molecular analysis for minimal residual disease following matched volunteer UD BMT for childhood ALL.