15,436 research outputs found
Multi-scale analysis of the surface layer urban heat island effect in five higher density precincts of central Sydney
The urban heat island (UHI) effect is invariably present in cities, mainly due to increased urbanisation. It can result in higher urban densities being significantly hotter (frequently more than 4°C, even up to 10°C) than their peri-urban surroundings. Urban structure and land cover are key contributors to the surface layer urban heat island (sUHI) effect at city and district scale. This research aims to explore which urban configurations can make urban precincts and their microclimates more resilient to the dangerous sUHI effect. In the context of the city of Sydney, Australia, the research aims to explore the most heat resilient urban features for neighbourhoods, at precinct scale. The investigation examines five high density precincts in central Sydney. The analysis of these precincts is based on remote sensing thermal data of two independent sources: a nocturnal remote-sensing thermal image of central Sydney on 6 February 2009 and a diurnal Landsat 7– ETM+ data from 2008-2009. Comparing the surface temperature of streetscape and buildings’ rooftop feature layers indicates that open spaces are the urban elements most sensitive to the sUHI effect. Therefore, the correlations between street network intensity, open public space ratio, and urban greenery plot ratio and sUHI effect are being analysed in the five high density precincts selected. Results indicate that a higher open space ratio and street network intensity have a significant correlation to a higher sUHI effect at precinct scale. However, higher urban greenery plot ratios could mitigate the sUHI effect in these precincts. In addition, annual variation of land use features of streetscape, building (rooftop), open space and urban greenery are being analysed based on diurnal Landsat 7– ETM+ data for 2008-2009. Results indicate that an increase in urban greenery is the most effective strategy for land surface that is more resilient to the sUHI, while open public space is up to 15 per cent less heat resilient. The research outcomes support the importance of increasing urban greenery, particularly in open public spaces, to achieve cooler cities.Ehsan Sharifi, Conrad Philipp and Steffen Lehman
Person prominence and relation prominence : on the typology of syntactic relations with particular reference to Yucatec Maya
PM3969, ISO 639-3 : -, Maya language--Syntax1. Introduction 2. Theoretical background 2.1. The cognitive structure of a situation 2.1.1. Situation, situation core, and participants 2.1.2. Participant features 2.1.3. Participant roles 2.2. Syntactic functions 2.3. Correlation between syntactic functions and participant roles 3. Prominence in typology 3.1. Subject prominence vs. topic prominence 3.2. Reference domination vs. role domination 3.3. Person prominence vs. relation prominence 4. Languages investigated 4.1. Yucatec Maya 4.2. Samoan 4.3. Maori 4.4. Tamil 4.5. Lezgian 4.6. Korean 5. Prominence in syntactic constructions 5.1. Introduction 5.2. Higher predicates 5.2.1. Modal predicates 5.2.2. Phase predicates 5.2.3. Tense, aspect, and aktionsart auxiliaries 5.3. Possessive constructions 5.3.1. Part-whole relations 5.3.2. Ascription of possession 5.3.3. Predication of belonging 5.3.4. Ascription of property to body part 5.3.5. Affection of possessor 5.4. Mental, sensual, and emotional states and processes 5.4.1. Preliminaries 5.4.2. Sensual states and processes 5.4.3. Emotional states and processes 5.4.4. Mental states and processes 5.4.5. Conclusion 5.5. Benefactive 6. Relation prominence in YM: a historical-comparative perspective 6.1. Colonial Yucatec Maya 6.1.1. Preliminaries 6.1.2. Modal predicates 6.1.3. Phase predicates 6.1.4. Aspect auxiliaries 6.1.5. Conclusion 6.2. Cognate languages 6.2.1. Preliminaries 6.2.2. Higher predicates 6.2.3. Possessive constructions 6.2.4. Mental, sensual and emotional states and processes 6.2.5. Benefactive 6.2.6. Conclusion 7. Typology 7.1. Empirical generalizations 7.1.1. The domain of possession 136 7.1.2. Higher predicates 7.1.3. Participant roles 7.2. Grammatical correlations 7.3. Conclusion Indices Abbreviations Morpheme glosses & syntactic categories Languages Sources of data Bibliographical references LIST OF FIGURES LIST OF TABLE
Proton Lifetime and Baryon Number Violating Signatures at the LHC in Gauge Extended Models
There exist a number of models in the literature in which the weak
interactions are derived from a chiral gauge theory based on a larger group
than SU(2)_L x U(1)_Y. Such theories can be constructed so as to be
anomaly-free and consistent with precision electroweak measurements, and may be
interpreted as a deconstruction of an extra dimension. They also provide
interesting insights into the issues of flavor and dynamical electroweak
symmetry breaking, and can help to raise the mass of the Higgs boson in
supersymmetric theories. In this work we show that these theories can also give
rise to baryon and lepton number violating processes, such as nucleon decay and
spectacular multijet events at colliders, via the instanton transitions
associated with the extended gauge group. For a particular model based on
SU(2)_1 x SU(2)_2, we find that the violating scattering cross sections
are too small to be observed at the LHC, but that the lower limit on the
lifetime of the proton implies an upper bound on the gauge couplings.Comment: 36 page
Influence of the pion-nucleon interaction on the collective pion flow in heavy ion reactions
We investigate the influence of the real part of the in-medium pion optical
potential on the pion dynamics in intermediate energy heavy ion reactions at 1
GeV/A. For different models, i.e. a phenomenological model and the
--hole model, a pionic potential is extracted from the dispersion
relation and used in Quantum Molecular Dynamics calculations. In addition with
the inelastic scattering processes we thus take care of both, real and
imaginary part of the pion optical potential. A strong influence of the real
pionic potential on the pion in-plane flow is observed. In general such a
potential has the tendency to reduce the anticorrelation of pion and nucleon
flow in non-central collisions.Comment: 12 pages Latex, 4 PS-figure
Formation and evolution of clumpy tidal tails around globular clusters
We present some results of numerical simulations of a globular cluster
orbiting in the central region of a triaxial galaxy on a set of 'loop' orbits.
Tails start forming after about a quarter of the globular cluster orbital
period and develop, in most cases, along the cluster orbit, showing clumpy
substructures as observed, for example, in Palomar 5. If completely detectable,
clumps can contain about 7,000 solar masses each, i.e. about 10% of the cluster
mass at that epoch. The morphology of tails and clumps and the kinematical
properties of stars in the tails are studied and compared with available
observational data. Our finding is that the stellar velocity dispersion tends
to level off at large radii, in agreement to that found for M15 and Omega
Centauri.Comment: LaTeX 2e, uses AASTeX v5.x, 40 pages with 18 figures. Submitted to
The Astronomical Journa
Quasi-Bayesian Nonparametric Density Estimation via Autoregressive Predictive Updates
Bayesian methods are a popular choice for statistical inference in small-data regimes due to the regularization effect induced by the prior. In the context of density estimation, the standard nonparametric Bayesian approach is to target the posterior predictive of the Dirichlet process mixture model. In general, direct estimation of the posterior predictive is intractable and so methods typically resort to approximating the posterior distribution as an intermediate step. The recent development of quasi-Bayesian predictive copula updates, however, has made it possible to perform tractable predictive density estimation without the need for posterior approximation. Although these estimators are computationally appealing, they struggle on non-smooth data distributions. This is due to the comparatively restrictive form of the likelihood models from which the proposed copula updates were derived. To address this shortcoming, we consider a Bayesian nonparametric model with an autoregressive likelihood decomposition and a Gaussian process prior. While the predictive update of such a model is typically intractable, we derive a quasi-Bayesian update that achieves state-of-the-art results in small-data regimes
The role of space, time and sociability in predicting social encounters
Space, time and the social realm are intrinsically linked. While an array of studies have tried to untangle these factors and their influence on human behaviour, hardly any have taken their effects into account at the same time. To disentangle these factors, we try to predict future encounters between students and assess how important social, spatial and temporal features are for prediction. We phrase our problem of predicting future encounters as a link-prediction problem and utilise set of Random Forest predictors for the prediction task. We use data collected by the Copenhagen network study; a study unique in scope and scale and tracks 847 students via mobile phones over the course of a whole academic year. We find that network and social features hold the highest discriminatory power for predicting future encounters
Soil mineral N dynamics beneath mixtures of leaves from legume and fruit trees in Central Amazonian multi-strata agroforests.
Dinâmica do nitrogênio mineral no solo em misturas de folhas de leguminosas arbóreas e de fruteiras em sistemas agroflorestais multiestratificados na Amazônia Central
Detailed studies of non-linear magneto-optical resonances at D1 excitation of Rb-85 and Rb-87 for partially resolved hyperfine F-levels
Experimental signals of non-linear magneto-optical resonances at D1
excitation of natural rubidium in a vapor cell have been obtained and described
with experimental accuracy by a detailed theoretical model based on the optical
Bloch equations. The D1 transition of rubidium is a challenging system to
analyze theoretically because it contains transitions that are only partially
resolved under Doppler broadening. The theoretical model took into account all
nearby transitions, the coherence properties of the exciting laser radiation,
and the mixing of magnetic sublevels in an external magnetic field and also
included averaging over the Doppler profile. Great care was taken to obtain
accurate experimental signals and avoid systematic errors. The experimental
signals were reproduced very well at each hyperfine transition and over a wide
range of laser power densities, beam diameters, and laser detunings from the
exact transition frequency. The bright resonance expected at the F_g=1 -->
F_e=2 transition of Rb-87 has been observed. A bright resonance was observed at
the F_g=2 --> F_e=3 transition of Rb-85, but displaced from the exact position
of the transition due to the influence of the nearby F_g=2 --> F_e=2
transition, which is a dark resonance whose contrast is almost two orders of
magnitude larger than the contrast of the bright resonance at the F_g=2 -->
F_e=3 transition. Even in this very delicate situation, the theoretical model
described in detail the experimental signals at different laser detunings.Comment: 11 pages, 9 figure
Wikipedia as an encyclopaedia of life
In his 2003 essay E O Wilson outlined his vision for an “encyclopaedia of life” comprising “an electronic page for each species of organism on Earth”, each page containing “the scientific name of the species, a pictorial or genomic presentation of the primary type specimen on which its name is based, and a summary of its diagnostic traits.” Although the “quiet revolution” in biodiversity informatics has generated numerous online resources, including some directly inspired by Wilson's essay (e.g., "http://ispecies.org":http://ispecies.org, "http://www.eol.org":http://www.eol.org), we are still some way from the goal of having available online all relevant information about a species, such as its taxonomy, evolutionary history, genomics, morphology, ecology, and behaviour. While the biodiversity community has been developing a plethora of databases, some with overlapping goals and duplicated content, Wikipedia has been slowly growing to the point where it now has over 100,000 pages on biological taxa. My goal in this essay is to explore the idea that, largely independent of the efforts of biodiversity informatics and well-funded international efforts, Wikipedia ("http://en.wikipedia.org/wiki/Main_Page":http://en.wikipedia.org/wiki/Main_Page) has emerged as potentially the best platform for fulfilling E O Wilson’s vision
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