126 research outputs found
Residents' diverse perspectives of the impact of neighbourhood renewal on quality of life and physical activity engagement: Improvements but unresolved issues
AbstractFew studies have been published on the reactions of residents to modifications of their residential landscape. We explored residents' experiences of home zone remodelling and construction of a new cycle-walkway in a deprived neighbourhood with a particular focus on aspects of quality of life and physical activity participation. Focus groups (n=5 groups, 21 individuals) were used to investigate residents' perceptions of the effects of neighbourhood change on their lives. Consultation by planners was received positively. Several aspects of the neighbourhood were perceived to have improved, including spatial aesthetics, lighting and streetscape planting. However, influence on physical activity was minimal. Car-focused behaviour and ownership remained dominant, and safety related concerns limited behavioural choices. Residents highlighted many socio-environmental challenges that remained such as sense of neighbourhood safety, poor public transport provision, people's parking behaviour locally, and problem neighbours, and these tended to dominate conversations. Infrastructural intervention may be one important part of multi-layered solutions to improved neighbourhood life
Affleck-Dine baryogenesis in the local domain
For Affleck-Dine baryogenesis to proceed, there must have been two types of
phase transitions. One is the destabilized-stabilized phase transition of the
flat direction, which is in general induced by the Hubble parameter. The other
is the phase transition related to the A-term, which induces the misalignment
of the relative phase of the flat direction. In the conventional Affleck-Dine
baryogenesis they are supposed to start almost simultaneously. Of course these
phase transitions can take place separately, but the latter must not be later
than the former because the phase transition of the A-term can not produce any
baryon number when there is no condensate of the relative charge.
In this paper we try to construct models where the original idea of
Affleck-Dine baryogenesis is realized in a different way. We show examples in
which the local domain of the false vacuum with the required condensate is
formed after inflation and collapses in a safe way so that the domain wall
problem is avoided. We also show examples where the phase transition of the
A-term starts before the decay of the condensate. As in the conventional
Affleck-Dine mechanism, the phase transition of the A-term produces baryon
number in the local domain of the condensate. We construct scenarios where our
mechanism produces sufficient baryon asymmetry of the Universe.Comment: 18pages, latex2e, to appear in PR
Majorana: from atomic and molecular, to nuclear physics
In the centennial of Ettore Majorana's birth (1906-1938?), we re-examine some
aspects of his fundamental scientific production in atomic and molecular
physics, including a not well known short communication. There, Majorana
critically discusses Fermi's solution of the celebrated Thomas-Fermi equation
for electron screening in atoms and positive ions. We argue that some of
Majorana's seminal contributions in molecular physics already prelude to the
idea of exchange interactions (or Heisenberg-Majorana forces) in his later
workson theoretical nuclear physics. In all his papers, he tended to emphasize
the symmetries at the basis of a physical problem, as well as the limitations,
rather than the advantages, of the approximations of the method employed.Comment: to appear in Found. Phy
A quantum Monte Carlo study of the one-dimensional ionic Hubbard model
Quantum Monte Carlo methods are used to study a quantum phase transition in a
1D Hubbard model with a staggered ionic potential (D). Using recently
formulated methods, the electronic polarization and localization are determined
directly from the correlated ground state wavefunction and compared to results
of previous work using exact diagonalization and Hartree-Fock. We find that the
model undergoes a thermodynamic transition from a band insulator (BI) to a
broken-symmetry bond ordered (BO) phase as the ratio of U/D is increased. Since
it is known that at D = 0 the usual Hubbard model is a Mott insulator (MI) with
no long-range order, we have searched for a second transition to this state by
(i) increasing U at fixed ionic potential (D) and (ii) decreasing D at fixed U.
We find no transition from the BO to MI state, and we propose that the MI state
in 1D is unstable to bond ordering under the addition of any finite ionic
potential. In real 1D systems the symmetric MI phase is never stable and the
transition is from a symmetric BI phase to a dimerized BO phase, with a
metallic point at the transition
Responses and adaptations of collembolan communities (Hexapoda: Collembola) to flooding and hypoxic conditions
Five decades of terrestrial and freshwater research at Ny-Ă lesund, Svalbard
For more than five decades, research has been conducted at Ny-Ă
lesund, in Svalbard, Norway, to understand the structure and functioning of High-Arctic ecosystems and the profound impacts on them of environmental change. Terrestrial, freshwater, glacial and marine ecosystems are accessible year-round from Ny-Ă
lesund, providing unique opportunities for interdisciplinary observational and experimental studies along physical, chemical, hydrological and climatic gradients. Here, we synthesize terrestrial and freshwater research at Ny-Ă
lesund and review current knowledge of biodiversity patterns, species population dynamics and interactions, ecosystem processes, biogeochemical cycles and anthropogenic impacts. There is now strong evidence of past and ongoing biotic changes caused by climate change, including negative effects on populations of many taxa and impacts of rain-on-snow events across multiple trophic levels. While species-level characteristics and responses are well understood for macro-organisms, major knowledge gaps exist for microbes, invertebrates and ecosystem-level processes. In order to fill current knowledge gaps, we recommend (1) maintaining monitoring efforts, while establishing a long-term ecosystem-based monitoring programme; (2) gaining a mechanistic understanding of environmental change impacts on processes and linkages in food webs; (3) identifying trophic interactions and cascades across ecosystems; and (4) integrating long-term data on microbial, invertebrate and freshwater communities, along with measurements of carbon and nutrient fluxes among soils, atmosphere, freshwaters and the marine environment. The synthesis here shows that the Ny-Ă
lesund study system has the characteristics needed to fill these gaps in knowledge, thereby enhancing our understanding of High-Arctic ecosystems and their responses to environmental variability and change
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
Eudialyte-group minerals from the Monte de Trigo alkaline suite, Brazil: composition and petrological implications
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