A conceptual framework for multi-modal interactive virtual workspaces

Construction projects involve a large number of both direct stakeholders (clients, professional teams, contractors, etc.) and indirect stakeholders (local authorities, residents, workers, etc.). Current methods of communicating building design information can lead to several types of difficulties (e.g. incomplete understanding of the planned construction, functional inefficiencies, inaccurate initial work or clashes between components, etc.). Integrated software solutions based on VR technologies can bring significant value improvement and cost reduction to the Construction Industry. The aim of this paper is to present research being carried out in the frame of the DIVERCITY project (Distributed Virtual Workspace for Enhancing Communication within the Construction Industry - IST project n°13365), funded under the European IST programme (Information Society Technologies). DIVERCITY's goal is to develop a Virtual Workspace that addresses three key building construction phases: (1) Client briefing (with detailed interaction between clients and architects); (2) Design Review (which requires detailed input from multidisciplinary teams - architects, engineers, facility managers, etc.); (3) Construction (aiming to fabricate or refurbish the building).Using a distributed architecture, the DIVERCITY system aims to support and enhance concurrent engineering practices for these three phases allowing teams based in different geographic locations to collaboratively design, test and validate shared virtual projects. The global DIVERCITY project will be presented in terms of objectives and the software architecture will be detailed.149-162Pubblicat

Time-Resolved AU-Scale Jets Traced by Masers in the IRAS 4A/B Regions of NGC1333

We present results of VLBI observations of the water masers associated with IRAS 4A and IRAS 4B in the NGC 1333 star-forming region taken in four epochs over a two month period. Both objects have been classified as extremely young sources and each source is known to be a multiple system. Using the Very Long Baseline Array, we detected 35 masers in Epoch I, 40 masers in Epoch II, 35 in Epoch III, and 24 in Epoch IV. Only one identified source in each system associates with these masers. These data are used to calculate proper motions for the masers and trace the jet outflows within 100 AU of IRAS 4A2 and IRAS 4BW. In IRAS 4A2 there are two groups of masers, one near the systemic cloud velocity and one red-shifted. They expand linearly away from each other at velocities of 53 km/s. In IRAS 4BW, masers are observed in two groups that are blue-shifted and red-shifted relative to the cloud velocity. They form complex linear structures with a thickness of 3 mas (1 AU at a distance of 320 pc) that expand linearly away from each other at velocities of 78 km/s. Neither of the jet outflows traced by the maser groups align with the larger scale outflows. We suggest the presence of unresolved companions to both IRAS 4A2 and 4BW.Comment: Accepted by Ap

The effects of problem-oriented policing on crime and disorder

Problem-oriented Policing (POP) was first introduced by Herman Goldstein in 1979. The approach was one of a series of responses to a crisis in effectiveness and legitimacy in policing that emerged in the 1970s and 1980s. Goldstein argued that police were not being effective in preventing and controlling crime because they had become too focused on the “means” of policing and had neglected the “goals” of preventing and controlling crime and other community problems. Goldstein argued that the unit of analysis in policing must become the “problem” rather than calls or crime incidents as was the case during that period. POP has had tremendous impact on American policing, and is now one of the most widely implemented policing strategies in the US. To synthesize the extant problem-oriented policing evaluation literature and assess the effects of problem-oriented policing on crime and disorder Eligible studies had to meet three criteria: (1) the SARA model was used for a problemoriented policing intervention; (2) a comparison group was included; (3) at least one crime or disorder outcome was reported with sufficient data to generate an effect size. The unit of analysis could be people or places. Several strategies were used to perform an exhaustive search for literature fitting the eligibility criteria. First, a keyword search was performed on an array of online abstract databases. Second, we reviewed the bibliographies of past reviews of problem-oriented policing. Third, we performed forward searches for works that have cited seminal problem-oriented policing studies. Fourth, we performed hand searches of leading journals in the field. Fifth, we searched the publications of several research and professional agencies. Sixth, after finishing the above searches we e-mailed the list of studies meeting our eligibility criteria to leading policing scholars knowledgeable in the area of problem-oriented policing to ensure we had not missed any relevant studies. For our ten eligible studies, we provide both a narrative review of effectiveness and a meta-analysis. For the meta-analysis, we coded all primary outcomes of the eligible studies and we report the mean effect size (for studies with more than one primary outcome, we averaged effects to create a mean), the largest effect, and the smallest effect. Because of the heterogeneity of our studies, we used a random effects model. Based on our meta-analysis, overall problem-oriented policing has a modest but statistically significant impact on reducing crime and disorder. Our results are consistent when examining both experimental and quasi-experimental studies. Conclusions: We conclude that problem-oriented policing is effective in reducing crime and disorder, although the effect is fairly modest. We urge caution in interpreting these results because of the small number of methodologically rigorous studies on POP and the diversity of problems and responses used in our eligible studies

Data from: Drought intensification drives turnover of structure and function in stream invertebrate communities

Climatic extremes are becoming more frequent and intense across much of the globe, potentially transforming the biodiversity and functioning of affected ecosystems. In freshwaters, hydrological extremes such as drought can regulate beta diversity, acting as powerful environmental filters to dictate the complement of species and functional traits found at local and landscape scales. New methods that enable beta diversity and its functional equivalent to be partitioned into turnover (replacement of species/functions) and nestedness-resultant (gain/loss of species/functions) components may offer novel insights into the parallel impacts of drought on ecosystem structure and function. Using a series of artificial channels (mesocosms) designed to mimic perennial headwater streams, we experimentally manipulated streamflows to simulate a gradient of drought intensity. We then modelled taxonomic and functional turnover and nestedness of macroinvertebrate communities along this gradient, validating direct gradient approaches (bootstrapping, Mantel tests) against null models of nestedness. Drought intensification produced significant environmental distance decay trends (i.e. communities became increasingly taxonomically and functionally dissimilar the more differentially disturbed by drought they were). Taxonomic distance decay was primarily driven by turnover, while the functional trend reflected a combination of richness differences and turnover at different points along the gradient. Taxonomic and functional distance decay slopes were not significantly different, implying that communities were functionally vulnerable to drying. The increased frequency and intensity of droughts predicted under most climate change scenarios could thus profoundly modify not only the structure of running water invertebrate communities, but also the ecosystem functions they underpin

Drought alters the functional stability of stream invertebrate communities through time

Aim: In fresh waters, most biogeographical understanding of how extreme events such as drought modify biodiversity and ecosystem functioning derives from static, spatial comparisons of ecological communities, between intact and disturbed sites or along stress gradients. Impacts of drought on the development of ecological communities over time remain poorly resolved, with information on parallel trends in community structure and function particularly scarce. In theory, drought could progressively eliminate both species and functional traits, rendering communities increasingly taxonomically and functionally nested subsets of their pre-existing counterparts. Alternatively, drought could create new niche opportunities, producing a continuous turnover of species and traits, or simply constrain natural community succession. Location: Dorset, UK. Taxon: Aquatic invertebrates.Methods: We studied temporal changes in community structure and function in artificial streams over 2 years, comparing drought (frequent drying) with control (constant flow) conditions. Temporal beta diversity was partitioned into turnover and nestedness components, calculated using both presence–absence and abundance data, and analysed using time-lag and null modelling approaches. Results: Community development was comparable taxonomically under control and drought conditions, driven primarily by temporal turnover of species. Under control conditions, corresponding trends in functional composition were not apparent, and species turnover was characterized by the progressive replacement of some species by others of equivalent abundance. By contrast, species turnover in disturbed communities was accompanied by both functional turnover and greater loss of individuals, indicating that new colonists were not equivalent, either functionally or numerically, to those they replaced. Furthermore, functional dissimilarities between time points were greatest under drought, and more similar in magnitude to taxonomic dissimilarities, implying that drying reduced the stability and redundancy of functional attributes.Main conclusion: A shift to drier climate could disrupt the natural development of stream community structure, and undermine functional stability, at local and biogeographical scales, with potentially significant consequences for ecosystem services provisioning in fresh waters

Extra terrestrials:drought creates niche space for rare invertebrates in a large-scale and long-term field experiment

Freshwater habitats are drying more frequently and for longer under the combined pressures of climate change and overabstraction. Unsurprisingly, many aquatic species decline or become locally extinct as their benthic habitat is lost during stream droughts, but less is known about the potential ‘winners’: those terrestrial species that may exploit emerging niches in drying riverbeds. In particular, we do not know how these transient ecotones will respond as droughts become more extreme in the future. To find out we used a large-scale, long-term mesocosm experiment spanning a wide gradient of drought intensity, from permanent flows to full streambed dewatering, and analysed terrestrial invertebrate community assembly after 1 year. Droughts that caused stream fragmentation gave rise to the most diverse terrestrial invertebrate assemblages, including 10 species with UK conservation designations, and high species turnover between experimental channels. Droughts that caused streambed dewatering produced lower terrestrial invertebrate richness, suggesting that the persistence of instream pools may benefit these taxa as well as aquatic biota. Particularly intense droughts may therefore yield relatively few ‘winners’ among either aquatic or terrestrial species, indicating that the threat to riverine biodiversity from future drought intensification could be more pervasive than widely acknowledged