1,123 research outputs found

    Local Government Spending on Public Housing: Factors of Influence in Metropolitan Areas

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    Rent or mortgage payments make up the largest portion of an American family’s budget. As there is a limited housing stock in metropolitan areas, low-income families struggle to find housing that is both adequate and affordable. Federal housing programs make funding available, but the provision of housing is left to local governments. Through the implementation of bold strategies and initiatives, local governments can help their low-income constituents find permanent housing for themselves and their families. Public housing in the U.S. is associated with dilapidation, overcrowding, and social disorganization. In the past, housing projects have been shortsighted measures aimed at addressing the most critical problems. Instead of providing permanent housing to low-income residents, the focus was to house as many people as possible in one project with high-rise buildings and small units. A strategy of the late 20th century was tearing down high-rise housing projects, which displaced the residents living therein. Now, 21st-century strategies are to proliferate mixed-income apartment buildings, ensuring that the buildings are architecturally sound, are well maintained, are permanent or semi-permanent residences, and have access to occupational and social services. This thesis evaluates social and intergovernmental factors affecting the provision of public housing by local governments in metropolitan areas across the U.S. The evidence revealed in this thesis provides analysis of data and findings that is useful to local governments, public housing authorities, non-profit housing organizations, federal and state programs supporting housing initiatives, private developers involved in low-income housing projects, and researchers interested in public housing policy

    Is mass loss along the red giant branch of globular clusters sharply peaked? The case of M3

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    There is a growing evidence that several globular clusters must contain multiple stellar generations, differing in helium content. This hypothesis has helped to interpret peculiar unexplained features in their horizontal branches. In this framework we model the peaked distribution of the RR Lyr periods in M3, that has defied explanation until now. At the same time, we try to reproduce the colour distribution of M3 horizontal branch stars. We find that only a very small dispersion in mass loss along the red giant branch reproduces with good accuracy the observational data. The enhanced and variable helium content among cluster stars is at the origin of the extension in colour of the horizontal branch, while the sharply peaked mass loss is necessary to reproduce the sharply peaked period distribution of RR Lyr variables. The dispersion in mass loss has to be <~ 0.003 Msun, to be compared with the usually assumed values of ~0.02 Msun. This requirement represents a substantial change in the interpretation of the physical mechanisms regulating the evolution of globular cluster stars.Comment: Accepted for publication in The Astrophysical Journa

    Sipunculus nudus: particulate components of the coelomic fluid and its relationship with brown bodies

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    Corpuscular components of the coelomic fluid were observed in Sipunculus nudus using cytochemical and cytoenzymatic methods. In particular, granulocytes were studied and two different types, based on morphology, chemical composition, and function were distinguished. Cell aggregates, identified as stem cells of type II granulocytes, were also evidenced. Besides, empty vesicles, vesicle fragments, laminar structures and brown bodies were observed. Based on the observation of their structure and ultrastructure, brown bodies were attributed with the function of accumulating foreign material, as well as aged components typical of the coelomic fluid

    Invasion threshold in heterogeneous metapopulation networks

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    We study the dynamics of epidemic and reaction-diffusion processes in metapopulation models with heterogeneous connectivity pattern. In SIR-like processes, along with the standard local epidemic threshold, the system exhibits a global invasion threshold. We provide an explicit expression of the threshold that sets a critical value of the diffusion/mobility rate below which the epidemic is not able to spread to a macroscopic fraction of subpopulations. The invasion threshold is found to be affected by the topological fluctuations of the metapopulation network. The presented results provide a general framework for the understanding of the effect of travel restrictions in epidemic containment.Comment: 4 pages, 2 figure

    Neuroendocrine cells in the urogenital tract of the buffalo

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    Neuroendocrine cells or paraneurons are cytotypes producing biogenic amines and/or hormonal peptides, scattered in the glandular and lining epithelia of the body. In this study the presence of chromogranin A-, serotonin- and somatostatin-immunoreactive neuroendocrine cells has been described immunohistochemically in the urethro- prostatic complex and female urethra of subjects of the buffalo Bubalus bubalis. The chromogranin A- containing neuroendocrine cells resulted the most numerous cytotype, the serotonin- containing ones the most irregular in shape for the presence of dendritic-like cytoplasmic extensions and the somatostatin- containing the rarest. The role played by the amine serotonin in the genital tract has been related to the determinism of sexual climax and to the contraction of smooth muscle. The function played by the neuroendocrine genital somatostatin is unknown. Analogically to what described for the same gastrointestinal hormone, it could inhibit both exocrine and endocrine secretions

    Observation of coherent Josephson response in the non-linear ab-plane microwave impedance of YBa2Cu3O6.95YBa_{2}Cu_{3}O_{6.95} single crystals

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    We report novel non-linear phenomena in the abab-plane microwave impedance of YBaCu2O7δYBaCu_{2}O_{7-\delta } single crystals. The RsR_s vs. HrfH_{rf} data are well described by the non-linear RSJ model : ϕ˙+sinϕ=irfcosωt\dot{\phi}+\sin \phi =i_{rf}\cos \omega t. The entire crystal behaves like a single Josephson junction. The extraordinary coherence of the data suggests an intrinsic mechanism.Comment: 2 pages,1 figure, Submitted to Proc. of M^2SHTSC-V (Beijing), also available at http://sagar.physics.neu.edu/preprint

    Application of users’ light-switch stochastic models to dynamic energy simulation

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    The design of an innovative building should include building overall energy flows estimation. They are principally related to main six influencing factors (IEA-ECB Annex 53): climate, building envelope and equipment, operation and maintenance, occupant behaviour and indoor environment conditions. Consequently, energy-related occupant behaviour should be taken into account by energy simulation software. Previous researches (Bourgeois et al. 2006, Buso 2012, Fabi 2012) already revealed the differences in terms of energy loads between considering occupants' behaviour as stochastic processes rather than deterministic inputs, due to the uncertain nature of human behaviour. In this paper, new stochastic models of users’ interaction with artificial lighting systems are developed and implemented in the energy simulation software IDA ICE. They were developed from field measurements in an office building in Prague. The aim is to evaluate the impact of a user's switching action over whole building energy consumption. Indeed, it is interesting not only to see the variance related to electric energy consumption, but the overall effect on a building's energy load

    Application of users’ light-switch stochastic models to dynamic energy simulation

    Get PDF
    The design of an innovative building should include building overall energy flows estimation. They are principally related to main six influencing factors (IEA-ECB Annex 53): climate, building envelope and equipment, operation and maintenance, occupant behaviour and indoor environment conditions. Consequently, energy-related occupant behaviour should be taken into account by energy simulation software. Previous researches (Bourgeois et al. 2006, Buso 2012, Fabi 2012) already revealed the differences in terms of energy loads between considering occupants' behaviour as stochastic processes rather than deterministic inputs, due to the uncertain nature of human behaviour. In this paper, new stochastic models of users’ interaction with artificial lighting systems are developed and implemented in the energy simulation software IDA ICE. They were developed from field measurements in an office building in Prague. The aim is to evaluate the impact of a user's switching action over whole building energy consumption. Indeed, it is interesting not only to see the variance related to electric energy consumption, but the overall effect on a building's energy load

    Optimal Paths in Complex Networks with Correlated Weights: The World-wide Airport Network

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    We study complex networks with weights, wijw_{ij}, associated with each link connecting node ii and jj. The weights are chosen to be correlated with the network topology in the form found in two real world examples, (a) the world-wide airport network, and (b) the {\it E. Coli} metabolic network. Here wijxij(kikj)αw_{ij} \sim x_{ij} (k_i k_j)^\alpha, where kik_i and kjk_j are the degrees of nodes ii and jj, xijx_{ij} is a random number and α\alpha represents the strength of the correlations. The case α>0\alpha > 0 represents correlation between weights and degree, while α<0\alpha < 0 represents anti-correlation and the case α=0\alpha = 0 reduces to the case of no correlations. We study the scaling of the lengths of the optimal paths, opt\ell_{\rm opt}, with the system size NN in strong disorder for scale-free networks for different α\alpha. We calculate the robustness of correlated scale-free networks with different α\alpha, and find the networks with α<0\alpha < 0 to be the most robust networks when compared to the other values of α\alpha. We propose an analytical method to study percolation phenomena on networks with this kind of correlation. We compare our simulation results with the real world-wide airport network, and we find good agreement

    Supercurvaton

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    We discuss observational consequences of the curvaton scenario, which naturally appears in the context of the simplest model of chaotic inflation in supergravity. The non-gaussianity parameter f_NL in this scenario can take values in the observationally interesting range from O(10) to O(100). These values may be different in different parts of the universe. The regions where f_NL is particularly large form a curvaton web resembling a net of thick domain walls, strings, or global monopoles.Comment: 17 pages, 1 figure. Non-perturbative effects related to non-gaussianity in the curvaton scenario are discussed, some references are added. This is the version accepted in JCA
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