453 research outputs found

    Proximity to Industrial Releases of Toxins and Childhood Respiratory, Developmental, and Neurological Diseases: Environmental Ascription in East Baton Rouge Parish

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    Recent research by Legot et al. (2010a, 2010b) has identified East Baton Rouge Parish (EBR) as a locus of particularly high volumes of emissions of developmental neurotoxins, i.e., those toxins that put children’s health and, especially, learning abilities at greatest risk. Many developmental neurotoxins are also classified as respiratory toxins, which are also linked to the sorts of childhood diseases (e.g., asthma) that impact school performance. This case study specifies the degree to which proximity to the main sources of these toxins in EBR is associated with high rates of neurodevelopmental diseases and childhood asthma. We also examine the relationship between proximity to toxins and race and class.<span>  </span>We find very strong patterns: disease rates are significantly higher in zip codes close to pollution “hot spots” than in more distant zip codes, as are percent minority and percent poverty.<span>  </span>This is evidence of “environmental ascription”, the existence of multiple, overlapping ascriptions based on race, class, and “place”.<span>  </span>Vulnerable populations are disproportionately exposed to the sorts of toxins that limit their life chances.<p></p>environmental ascription; developmental neurotoxins; respiratory toxins; childhood diseases; vulnerable populations

    The Proximity of High Volume Developmental Neurotoxin Polluters to Schools: Vulnerable Populations at Risk

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    A substantial amount of environmental justice research has taken the form of “proximity studies” that analyze the race and class composition of populations living in close proximity to general sources of pollution. Such studies often find disproportionate minority, poverty, and low-income populations proximate to the pollution source. This proximity study has a different starting point. We begin by locating nearly 700 of the nation’s highest volume polluters of specific toxins that put children’s health and learning abilities at risk: developmental neurotoxins. We then examine (a) the numbers of schools and children located within two miles of each polluter, and (b) the race and class compositions of the populations within two miles. The result is a study of the proximity of vulnerable populations to pollution that highlights the vulnerability of children, not just that of minorities and the poor. We find thousands of schools and hundreds of thousands of children at risk. We also find that a substantial proportion of the high volume polluters studied are surrounded by disproportionate minority, poverty, and low-income populations.proximity studies; environmental inequality; developmental toxins; neurotoxins; high-volume polluters; vulnerable populations: race and class, schools and children

    Entropic lattice Boltzmann methods

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    We present a general methodology for constructing lattice Boltzmann models of hydrodynamics with certain desired features of statistical physics and kinetic theory. We show how a methodology of linear programming theory, known as Fourier-Motzkin elimination, provides an important tool for visualizing the state space of lattice Boltzmann algorithms that conserve a given set of moments of the distribution function. We show how such models can be endowed with a Lyapunov functional, analogous to Boltzmann's H, resulting in unconditional numerical stability. Using the Chapman-Enskog analysis and numerical simulation, we demonstrate that such entropically stabilized lattice Boltzmann algorithms, while fully explicit and perfectly conservative, may achieve remarkably low values for transport coefficients, such as viscosity. Indeed, the lowest such attainable values are limited only by considerations of accuracy, rather than stability. The method thus holds promise for high-Reynolds number simulations of the Navier-Stokes equations.Comment: 54 pages, 16 figures. Proc. R. Soc. London A (in press

    Hierarchical Trustworthy Authentication for Pervasive Computing

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    Evaluation of Norepinephrine Transporter Expression and Metaiodobenzylguanidine Avidity in Neuroblastoma: A Report from the Childrens Oncology Group.

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    Purpose. (123)I-metaiodobenzylguanidine (MIBG) is used for the diagnostic evaluation of neuroblastoma. We evaluated the relationship between norepinephrine transporter (NET) expression and clinical MIBG uptake. Methods. Quantitative reverse transcription PCR (N = 82) and immunohistochemistry (IHC; N = 61) were performed for neuroblastoma NET mRNA and protein expression and correlated with MIBG avidity on diagnostic scans. The correlation of NET expression with clinical features was also performed. Results. Median NET mRNA expression level for the 19 MIBG avid patients was 12.9% (range 1.6-73.7%) versus 5.9% (range 0.6-110.0%) for the 8 nonavid patients (P = 0.31). Median percent NET protein expression was 50% (range 0-100%) in MIBG avid patients compared to 10% (range 0-80%) in nonavid patients (P = 0.027). MYCN amplified tumors had lower NET protein expression compared to nonamplified tumors (10% versus 50%; P = 0.0002). Conclusions. NET protein expression in neuroblastoma correlates with MIBG avidity. MYCN amplified tumors have lower NET protein expression

    Modelling and Analysis of TCP Performance in Wireless Multihop Networks

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    Researchers have used extensive simulation and experimental studies to understand TCP performance in wireless multihop networks. In contrast, the objective of this paper is to theoretically analyze TCP performance in this environment. By examining the case of running one TCP session over a string topology, a system model for analyzing TCP performance in multihop wireless networks is proposed, which considers packet buffering, contention of nodes for access to the wireless channel, and spatial reuse of the wireless channel. Markov chain modelling is applied to analyze this system model. Analytical results show that when the number of hops that the TCP session crosses is fixed, the TCP throughput is independent of the TCP congestion window size. When the number of hops increases from one, the TCP throughput decreases first, and then stabilizes when the number of hops becomes large. The analysis is validated by comparing the numerical and simulation result

    Supernova hydrodynamics experiments on the Nova laser

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    In studying complex astrophysical phenomena such as supernovae, one does not have the luxury of setting up clean, well-controlled experiments in the universe to test the physics of current models and theories. Consequently, creating a surrogate environment to serve as an experimental astrophysics testbed would be highly beneficial. The existence of highly sophisticated, modern research lasers, developed largely as a result of the world-wide effort in inertial confinement fusion, opens a new potential for creating just such an experimental testbed utilizing well-controlled, well-diagnosed laser-produced plasmas. Two areas of physics critical to an understanding of supernovae are discussed that are amenable to supporting research on large lasers: (1) compressible nonlinear hydrodynamic mixing and (2) radiative shock hydrodynamics. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69962/2/PHPAEN-4-5-1994-1.pd

    A purchase protocol with multichannel authentication

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    While online shopping are becoming more accepted by people in modern life, cardholders are more concerned about card fraud and the lack of cardholder authentication in the current online credit card payment. This paper proposes a purchase protocol with live cardholder authentication for online transactions which combines telephone banking and online banking together. The order information and payment information are sent though the Internet and encrypted by asymmetric key encryption. The cardholder is authenticated by the card issuing bank ringing back at the customer’s phone number and the cardholder inputting the secure PIN and the amount to pay. The multichannel authentication makes the cardholder feel secure and card fraud difficult. Furthermore, the protocol does not require the cardholder to obtain public key certificates or install additional software for online transactions

    Supernova hydrodynamics experiments on Nova

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    We are developing experiments using the Nova laser to investigate (1) compressible nonlinear hydrodynamic mixing relevant to the first few hours of the supernova (SN) explosion and (2) ejecta-ambient plasma interactions relevant to the early SN remnant phase. The experiments and astrophysical implications are discussed. We discuss additional experiments possible with ultra-high-intensity lasers. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87451/2/551_1.pd
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