1,953 research outputs found

    The Vital Role of Faith Communities in the Lives of Urban Refugees

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    The majority of the world’s refugees do not live in refugee camps, but in cities around the world. Realities for urban refugees are vastly different from the conditions of a refugee camp. Urban refugees lack the institutional supports of official refugee camps and often have minimal legal covering in their host cities. Without government support and the limited capacity of UNHCR to provide adequate help, it is left to citizens of the host cities to provide help. Kuala Lumpur (KL) is home to more than 150,000 refugees and even more asylum seekers. These population numbers could be overwhelming to a city without help from its citizenry. This paper will examine ways in which Christian churches have welcomed and helped this large refugee population when few others would help. Guided by a biblical command to welcome “the strangerâ€, churches have sacrificed greatly to impact the lives of refugees in several key areas: education, employment, health care, and spiritual vitality. Because faith communities operate outside of governmental and non-governmental bureaucratic structures, their work often goes unnoticed. The work of these faith communities in KL is not an isolated event but serves as one case study of similar work happening in cities all over the world

    Effects of stress and water saturation on seismic velocity and attenuation in near surface sediments

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    Seismic investigation in the near-surface is complicated by highly attenuating media, large interparticle stresses, and variable water saturation, so new tools and methodology are necessary to understand the relationships between velocity, attenuation, and physical properties of the propagating media. A new shear wave source is developed for investigation of gas-charged, organic-rich sediments because compressional waves are highly attenuated and currently available sources are inadequate. The new source compares favorably to a traditional hammer impact source, producing a signal with a broader-band of frequencies (30-100Hz cf. 30-60Hz) and signal-to-noise ratios (SNR) equivalent to ~3 stacked hammer blows to the hammer impact source. Ideal source signals must be broadband in frequency, have a high SNR, be consistent, and have precise start times; all traits of the new shear source. A new constitutive model predicting seismic velocity is developed because current models do not include interparticle stresses which are especially important in materials with large cohesive and capillary pressures such as clays. The new proposed methodology calculates elastic moduli of granular matrices in near-surface environments by incorporating an updated definition of total effective stress into Hertz-Mindlin theory and calculates the elastic moduli of granular materials by extending Biot-Gassmann theory to include pressure effects induced by water saturation. As water saturation increases in shallow sediments, theoretically calculated seismic velocities decrease in clay and increase in sand because of the respective interparticle stresses in these media. The proposed model calculates seismic velocities that compare well with measured field velocities from the literature. A field-transferrable lab experiment shows the simultaneous dependence of quality factor (Q) on water saturation and stress in unconsolidated sand. Local Q values (Qint) increase the most with depth (dQ/dz=43 m-1) and stress (dQ/dS=0.0025/Pa) in dry sand and the least in partially saturated sand (dQ/dz=10m-1 and dQ/dS=0.0013/Pa) where attenuation created by local fluid flow reaches a maximum. Expectations for Qint values with depth can be extrapolated from dQ/dS and are bounded by Qint of the dry (QD) and partially saturated (QPS) media (e.g.,QD\u3eQint\u3eQPS). Qint deviations outside this range can be explained by a divergence in effective stress, attenuation mechanism, or lithology

    Short Distance Ground Wave Propagation Modeling in Irregular and Forested Environments

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    A model for the phase of a ground wave propagating over irregular and forested terrain has been developed and tested for a transmission system operating at 3.315 MHz. In this model, the time delay induced beyond that of the standard velocity of radio waves in air is modeled as a combination of 3 effects: the finite conductivity of the earth, the irregularity of the terrain over which the wave is propagating, and the forestation of the terrain. The finite conductivity model is based on a small curvature formula developed by Van Der Pol and Bremmer. The terrain irregularity model models additional delay as a perturbation of the surface impedance and is a function of the slope angle. The additional delay due to forestation is modeled as a dissipative dielectric slab which introduces a velocity factor. The foliage on the range was quantized into three levels of density: open, thin, and thick. The foliage thickness was determined manually from commercial satellite imagery. The ground based network used to measure propagation times consists of 5 perimeter transmitter sites and 5 receiver sites. Results for 1 of the 5 receiver sites have already been obtained. The results accurately predict the additional delay time introduced. The additional delays predicted over the 5 paths vary widely, ranging from 400 to almost 1000 nanoseconds. The lengths of these paths vary between 2 and 3 miles. The relative permittivity of each grade of forest density along each path was found to be in agreement. The significance of this work revolves around navigating in GPS denied environments, areas of chronic GPS unavailability, such as urban areas, canyons, under dense foliage, or when a GPS signal is being unintentionally or intentionally jammed. In order to provide a path forward to a robust augmentation to GPS, the propagation phenomena associated with ground-based navigation must be understood, and more effectively modeled

    Managing for change: February 14, 1989

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    Bi-weekly newsletter of University Hospital's Change Project, provided to managers at the hospital

    Panel I

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    A World Without Women: Faulkner, Gender, and Genre / Brian Crane, Champlain College Crashes, Gangsters, and Plantation Houses: Absalom, Absalom! and the 1930s Gangster Film / Phillip Davis, University of Tulsa Light in August, Absalom, Absalom!, and Hechtian Industrial Screenwriting / Michael Holgate and Aaron Nyerges, University of Sydne

    Probing finite-temperature observables in quantum simulators with short-time dynamics

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    Preparing low temperature states in quantum simulators is challenging due to their almost perfect isolation from the environment. Here, we show how finite-temperature observables can be obtained with an algorithm that consists of classical importance sampling of initial states and a measurement of the Loschmidt echo with a quantum simulator. We use the method as a quantum-inspired classical algorithm and simulate the protocol with matrix product states to analyze the requirements on a quantum simulator. This way, we show that a finite temperature phase transition in the long-range transverse field Ising model can be characterized in trapped ion quantum simulators. We propose a concrete measurement protocol for the Loschmidt echo and discuss the influence of measurement noise, dephasing, as well as state preparation and measurement errors. We argue that the algorithm is robust against those imperfections under realistic conditions. The algorithm can be readily applied to study low-temperature properties in various quantum simulation platforms.Comment: 4+3 pages, 4+1 figure
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