2,865 research outputs found
The potential impact on Florida-based marina and boating industries of a post-embargo Cuba: an analysis of geographic, physical, policy and industry trends
The information in this Technical Paper addresses the future of the US-Cuban marina and recreational
boating industries from the geographic, physical, policy making and economic perspectives for a post-embargo Cuba.
Each individual paper builds on the presentations made at the workshop, the information obtained in the subsequent trip
to Cuba and presents in detailed form information which we hope is useful to all readers. (147pp.
A Triple Origin for the Heavy and Low-Spin Binary Black Holes Detected by LIGO/Virgo
We explore the masses, merger rates, eccentricities, and spins for field
binary black holes driven to merger by a third companion through the
Lidov-Kozai mechanism. Using a population synthesis approach, we model the
creation of stellar-mass black hole triples across a range of different initial
conditions and stellar metallicities. We find that the production of
triple-mediated mergers is enhanced at low metallicities by a factor of ~100
due to the lower black hole natal kicks and reduced stellar mass loss. These
triples naturally yield heavy binary black holes with near-zero effective
spins, consistent with most of the mergers observed to date. This process
produces a merger rate of between 2 and 25 Gpc^-3 yr^-1 in the local universe,
suggesting that the Lidov-Kozai mechanism can potentially explain all of the
low-spin, heavy black hole mergers observed by Advanced LIGO/Virgo. Finally, we
show that triples admit a unique eccentricity and spin distribution that will
allow this model to be tested in the near future.Comment: 18 Pages, 13 Figures, Accepted ApJ. Section 2 is most interesting to
dynamicists, while Sections 5 and 6 are most interesting to
gravitational-wave astronomer
Differential neuropsychological profiles in Parkinsonian patients with or without vascular lesions.
The purpose of this study is to compare the neuropsychological profile of patients affected by parkinsonism and vascular lesions to that in patients with PD alone (PD) and to evaluate whether the brain vascular lesion load is associated with neuropsychological variables. Thirty-six nondemented patients
with parkinsonism were divided into 3 groups of 12 patients each, according to both clinical history and the presence of brain vascular lesions and/or dopaminergic denervation as revealed by magnetic resonance and dopamine transporter imaging, respectively. The first group had vascular lesions without
dopaminergic denervation (VP group); the second group had vascular lesions and dopaminergic denervation (DD) (VP+DD group); and the third group consisted of patients with dopaminergic denervation (PD group) without vascular lesions. All
patients underwent neurological and neuropsychological assessments. The groups differed in disease duration, age at onset, and cerebrovascular risk factors. The VP and VP+DD groups performed worse than the PD group on frontal/executive tasks. Regardless of the presence of dopaminergic denervation, cerebrovascular lesions in hemispheric white matter, basal ganglia, and cerebellum have an important effect in determining early onset and severity of cognitive impairment in patients with parkinsonism
Mixed integral-differential skin-effect models for PEEC electromagnetic solver
Efficient modeling of the broadband skin-effect for conducting 3D shapes is a challenging issue for the solution of large electromagnetic problems. The inclusion of such models in an EM solver can be very costly in compute time and memory requirements. Several properties of a model are desirable for the solution of practical problems such as the broadband frequency domain or the time domain applicability. In this paper, we present a model which meets some of these challenges and which is suitable for the PEEC solution method. © 2011 IEEE.published_or_final_versionThe IEEE 20th Conference on Electrical Performance of Electronic Packaging and Systems (EPEPS 2011), San Jose, CA., 23-26 October 2011. In Proceedings of IEEE 20th EPEPS, 2011, p. 177-18
Urban commoning in a civic social network: the case study of FirstLife
The integration of ICTs in the urban management is increasing at all levels of public administrations in order to improve efficiency and effectiveness of public services, but their role is still instrumental rather than drive a change toward a more collaborative local governance. On the other hand, there is a raising expectation of the civil society to participate in decision making processes and contribute in defining local policies about sensitive topics. These purposes are often addressed by using or creating community digital tools designed for a specific contextual scope, resulting in a deep fragmentation of information about civic initiatives and social innovation projects and a lack of continuous communication among urban stakeholders even working in the same area. The challenge is to design an ICT solution to refactor the current practices of cooperation between private and public sector and support a real change in the city management processes from the local to the territorial level. In this contribution, we present the development of FirstLife, a map-based civic social network, designed to represent the complex environment of the city through geo-referenced time framed crowdsourced data about urban entities as events, places, groups, initiatives, projects, stories, news, etc. The main goals of the platform are to support the action of multiple stakeholders in alternative processes of co-management of common or shared resources, as for instance public spaces, green areas and buildings hosting collective institutions, to enable the co-production of services based on a reform of local administrative protocols toward the We-government model, and to empower mixed local networks. The development of FirstLife followed a participatory action design research methodology involving several stakeholders among associations, local authorities and institutions, businesses and the University in the city of Turin in the last two years. The participatory process started from the requirement elicitation, and continued with the collection of applicative scenarios based on the context analysis of internal/external relations of groups of stakeholders and the balancing of their goals in a common platform. Then, the co-design of features has been undertaken in the stakeholders’ working environments to model the platform functionalities on the real processes and practices defining social acceptable technological solutions, ready to be adopted by institutional and civic organizations. The platform has been tested-in-use in multiple living labs and pilot projects, experimenting a number of use patterns representing the common actions in the city carried out by public or private actors. These activities have been integrated in an iterative development cycle that brought so far at four progressively improved versions of FirstLife, from a map-based tool to share georeferenced information to a common workbench for multiple stakeholders acting in the same area (from the neighbourhood to the city level) where open groups can self-organize initiatives and cooperate with others. The result of this process is a digital space for urban commoning practices,reflecting the organization of society in individuals and structured public and private entities, the spatial framework of their actions and the temporal development of city transformations and initiatives
Are the next-generation households ready for the energy transition? A survey on their positioning and practice with energy management tools
In the last decades, significant effort has been put towards technological advancement in housing for energy transition. Massive retrofitting actions have been called for, and innovative technologies for smart energy management at home have been deployed. However, undesired energy trends in housing suggest that relevant factors have been neglected. Among these, increasing importance is now given to occupants' behaviour, and their capacity to interact with energy management devices available in dwellings. This study investigates what is the position of next-generation users on energy transition at home. Two years ago, the authors launched a survey to explore people's awareness of energy use practices, interaction with metering devices, and user motivation to change when informed. As a pilot survey, over 300 people from the academy were involved to see what was the position of a sample which was supposed to be informed more than the average, in Italy. The test yielded early outcomes on how people become more interested to change as they gain knowledge and are offered suggestions. Despite the expectations, the sample's level of awareness was low. This suggested that a more user-centred approach is needed for wide-scale progress. Especially results from the youngest were below prospects. The questionnaire was relaunched to examine if the pandemic, energy crisis and latest news on climate change have affected positions of the youngsters. A testing session involving university students was performed, and results have been compared with the previous. As a result, reflections on the energy use patterns of the next-generation households are provided
Black hole mergers and blue stragglers from hierarchical triples formed in globular clusters
Hierarchical triple-star systems are expected to form frequently via close
binary-binary encounters in the dense cores of globular clusters. In a
sufficiently inclined triple, gravitational interactions between the inner and
outer binary can cause large-amplitude oscillations in the eccentricity of the
inner orbit ("Lidov-Kozai cycles"), which can lead to a collision and merger of
the two inner components. In this paper we use Monte Carlo models of dense star
clusters to identify all triple systems formed dynamically and we compute their
evolution using a highly accurate three-body integrator which incorporates
relativistic and tidal effects. We find that a large fraction of these triples
evolve through a non-secular dynamical phase which can drive the inner binary
to higher eccentricities than predicted by the standard secular perturbation
theory (even including octupole-order terms). We place constraints on the
importance of Lidov-Kozai-induced mergers for producing: (i) gravitational wave
sources detectable by Advanced LIGO (aLIGO), for triples with an inner pair of
stellar black holes; and (ii) blue straggler stars, for triples with
main-sequence-star components. We find a realistic aLIGO detection rate of
black hole mergers due to the Lidov-Kozai mechanism of 1yr^-1, with about 20%
of these having a finite eccentricity when they first chirp into the aLIGO
frequency band. While rare, these events are likely to dominate among eccentric
compact object inspirals that are potentially detectable by aLIGO. For blue
stragglers, we find that the Lidov-Kozai mechanism can contribute only up to
~10% of their total numbers in globular clusters.Comment: 17 pages, 11 Figures. Accepted for publication in Ap
Trust and expected costs as antecedents of citizens’ motivation to participate in public policymaking
Objectives. The present study aimed at testing whether costs, trustworthiness of government, and expected voice could predict citizens' willingness to get involved in participatory governance processes. Participants and setting. Research participants were one-hundred and ninety-two volunteer students of Sapienza University of Rome, 66% female. Hypotheses. We hypothesized both main effects of trust (positive) and expected costs (negative) and an interactive effect of the two variables on citizens' willingness to participate. We also expected voice to be a mediator of such an interaction effect on willingness to participate. Statistical analyses. A 2 (costs) by 2 (trust) ANOVA was applied both to manipulation checks and to motivation to participate. Following this, we performed a bootstrap mediated moderation analysis (Hayes, 2013). Results. Motivation to participate was significantly affected by trust, in fact participants in the high trust condition, were more willing to participate (M= 3.84, SD = .91) rather than those in the low trust condition (M = 3.31, SD = .99). Also, a main effect of costs emerged, with low costs inducing higher motivation to participate (M = 3.73, SD = .92) than high costs (M = 3.41, SD = 1.03). More importantly, these effects were qualified by the predicted interaction between costs and trust: while in the high trust condition costs did not affect willingness to participate, in the low costs condition they made a significant difference. Finally, mediated moderation analysis showed that that expected voice was responsible for the impact of the trust by costs interaction on motivation to participate. Limitation. The main limitation of the study concerns generalizability of its results across populations of different ages and occupation
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