Urban Infrastructure: Transportation, Public Utilities, Waste Management and Pollution Control

Paris, tube under the channel -- London, satellite spinning above cables on the ocean floor -- New York, concrete ribbons across undulating land -- San Francisco, silver wings soaring across the Pacific -- Tokyo and Seoul. Etched against the sky are the graceful towers of mighty bridges, the broad glass and steel fronts to massive buildings, the tall slender stacks of industries exhaling; and traced on the surface are the intricate patterns of people and their machines; and buried below are the tubes and tunnels, water pipes and power conduits and communication networks along with concrete caissons and piles that penetrate towards the earth heart seeking assurance of a solid foundation. There in the bowels of the earth lies the entrails, and there piercing the sky towers the head of civilization; but here stands humankind, the heart and mind of that civilization, asking ourselves are we standing on feet of clay

CD40-Mediated Activation of the NF-κB2 Pathway

CD40 is a critical stimulatory receptor on antigen-presenting cells of the immune system. CD40-mediated activation of B cells is particularly important for normal humoral immune function. Engagement of CD40 by its ligand, CD154, on the surface of activated T cells initiates a variety of signals in B cells including the activation of MAP kinases and NF-κB. The transcriptional regulator NF-κB is in reality a family of factors that can promote B cell activation, differentiation, and proliferation. Complex – and only partially understood – biochemical mechanisms allow CD40 to trigger two distinct NF-κB activation pathways resulting in the activation of canonical (NF-κB1) and non-canonical (NF-κB2) NF-κB. This brief review provides a summary of mechanisms responsible for activation of the latter, which appears to be particularly important for enhancing the viability of B cells at various stages in their life cycle and may also contribute to the development of B cell malignancies. CD40 is also expressed by various cell types in addition to B cells, including T cells, macrophages, dendritic cells, as well as certain non-hematopoietic cells. Here too, while perhaps less extensively studied than in B cells, the CD40-mediated activation of NF-κB2 also appears to have important roles in cellular physiology

An Economic Evaluation of the Salinity Impacts from Energy Development: The Case of the Upper Colorado River Basin

To analyze the effect of potential energy development on water allocation and water quality in the Upper Colorado River Basin, a linear programming model is formulated. Using the model, changes in salinity are predicted. Further, least-cost strategies to maintain the established numeric salinity criteria through both structural and nonstructural alternatives are developed. The effectiveness of alternative control measures are examined within given institutional constraints. Based on cost-benefit analysis, optimal salinity levels over time are proposed. The economic feasibility of presently planned strucutral measures to reduce salinity is investigated and contrasted with nonstructural alternatives

Requirement for TRAF3 in Signaling by LMP1 But Not CD40 in B Lymphocytes

CD40, a member of the tumor necrosis factor receptor family, and the Epstein-Barr virus–encoded oncoprotein latent membrane protein 1 (LMP1) share several tumor necrosis factor receptor–associated factor (TRAF) adaptor proteins for signaling. Among these, TRAF3 was the first identified to directly bind both receptors, yet its role remains a mystery. To address this, we generated B cell lines deficient in TRAF3 by homologous recombination. We found that CD40 signals were normal in the absence of TRAF3, with the exception of moderately enhanced c-Jun NH2-terminal kinase (JNK) activation and antibody secretion. In sharp contrast, LMP1 signaling was markedly defective in TRAF3−/− B cells. LMP1-induced activation of JNK and nuclear factor κB, up-regulation of CD23 and CD80, and antibody secretion were substantially affected by TRAF3 deficiency. Reconstitution of TRAF3 expression decreased CD40-induced JNK activation and antibody secretion, and fully restored LMP1 signaling. Although TRAF2 is widely believed to be important for LMP1 function, LMP1 signaling was intact in TRAF2−/− B cells. Our data reveal that CD40 and LMP1 unexpectedly use TRAF3 in different ways, and that TRAF3 is required for LMP1-mediated activation of B cells

Cost Minimization for Coal Conversion Pollution Control: A Mixed Integer Programming Model

A mixed integer program was structured to identify the least cost combination of recycling and treatment alternatives that can be used to control the liquid, solid, and gas waste streams produced from a 750-megawatt coat fired steam electric power plant. The model compared methods of liquid stream recycle and waste discharge treatment to meet given air and water quality standards. The model was then used to study the effects on the optimal solution of changes in capital, operation and maintenance, and energy and water costs. In addition, the effects on optimum system design of changes in particulate and sulfur oxide emission standards and stream discharge standards were evaluated. Nonlinear cost functions for system components were structured with binary integer variables to define the ordinate intercept and with continuous variables to define the slopes of total cost curve segments. The binary and continuous variables were associated with each other in pairs to approximate nonlinear total cost functions of alternative pollution control units. The optimal plant design was sensitive to increases in capital, operation and maintenance, and energy costs as well as air emission standard changes. The model indentified the optimal treatment until alternatives and their sizes when segments of the total costs and environmental standards were changed. The optimal solutions always indentified water recycle, rather than stream discharge, as the optimal production strategy

A quantum Peierls-Nabarro barrier

Kink dynamics in spatially discrete nonlinear Klein-Gordon systems is considered. For special choices of the substrate potential, such systems support continuous translation orbits of static kinks with no (classical) Peierls-Nabarro barrier. It is shown that these kinks experience, nevertheless, a lattice-periodic confining potential, due to purely quantum effects anaolgous to the Casimir effect of quantum field theory. The resulting ``quantum Peierls-Nabarro potential'' may be calculated in the weak coupling approximation by a simple and computationally cheap numerical algorithm, which is applied, for purposes of illustration, to a certain two-parameter family of substrates.Comment: 13 pages LaTeX, 7 figure

A Methodology for Estimating Instream Flow Values for Recreation

Water flowing in streams has value for various types of recreationists and is essential for fish and wildlife. Since water demdns for offstream uses in the arid west have been steadily increasing, increasing instream flows to enhance the recreational experience might be in conflict with established withdrawals for uses such as agriculture, industries, and households. Since market prices are not observable for instream flows, the estimation of economic value of instream flow would present well known difficulties. The household production function theory was used to build the theoretical model to measure economic value of instream flow. A representative sample of 500 recreationists at three river sites were interviewed during the summer of 1982, to estimate empirical demand equation for recreational activities. In order to estimate economic value of water used in the river, it was assumed taht individuals were combining goods, services, and time as input to produce recreational services. Based on this procedure, empirical estimates of multisite demands were derived. Moreover, the corresponding \u27compensating variations\u27 of consumers, from alteration of instream flow, were quantified

Strength and conditioning in schools: a strategy to optimise health, fitness and physical activity in youths

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