35 research outputs found

    Integrated water management with reuse: A programing approach

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    This is the published version. Copyright 1979 by American Geophysical Union.Interest has increased recently in water recycling and reuse. The possible economic feasibility of reuse and recycling dramatically increases the complexity of designing an optimal water delivery system. In this paper we present a nonlinear model which takes into account both flow requirements and water quality. Because of the model's transshipment formulation the solution technique seems to be effective in aiding the design decisions

    Predictors of invertebrate biomass and rate of advancement of invertebrate phenology across eight sites in the North American Arctic

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    Average annual temperatures in the Arctic increased by 2–3 Β°C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of shorebirds and the invertebrate prey essential for egg formation and subsequent chick survival. To explore the environmental drivers afecting invertebrate availability, we modeled the biomass of invertebrates captured in modifed Malaise-pitfall traps over three summers at eight Arctic Shorebird Demographics Network sites as a function of accumulated degree-days and other weather variables. To assess climate-driven changes in invertebrate phenology, we used data from the nearest long-term weather stations to hindcast invertebrate availability over 63 summers, 1950–2012. Our results confrmed the importance of both accumulated and daily temperatures as predictors of invertebrate availability while also showing that wind speed negatively afected invertebrate availability at the majority of sites. Additionally, our results suggest that seasonal prey avail ability for Arctic shorebirds is occurring earlier and that the potential for trophic mismatch is greatest at the northernmost sites, where hindcast invertebrate phenology advanced by approximately 1–2.5 days per decade. Phenological mismatch could have long-term population-level efects on shorebird species that are unable to adjust their breeding schedules to the increasingly earlier invertebrate phenologies.publishedVersio

    Macrophages in Alzheimer’s disease: the blood-borne identity

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    Alzheimer’s disease (AD) is a progressive and incurable neurodegenerative disorder clinically characterized by cognitive decline involving loss of memory, reasoning and linguistic ability. The amyloid cascade hypothesis holds that mismetabolism and aggregation of neurotoxic amyloid-Ξ² (AΞ²) peptides, which are deposited as amyloid plaques, are the central etiological events in AD. Recent evidence from AD mouse models suggests that blood-borne mononuclear phagocytes are capable of infiltrating the brain and restricting Ξ²-amyloid plaques, thereby limiting disease progression. These observations raise at least three key questions: (1) what is the cell of origin for macrophages in the AD brain, (2) do blood-borne macrophages impact the pathophysiology of AD and (3) could these enigmatic cells be therapeutically targeted to curb cerebral amyloidosis and thereby slow disease progression? This review begins with a historical perspective of peripheral mononuclear phagocytes in AD, and moves on to critically consider the controversy surrounding their identity as distinct from brain-resident microglia and their potential impact on AD pathology

    Extensive innate immune gene activation accompanies brain aging, increasing vulnerability to cognitive decline and neurodegeneration: a microarray study

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    BACKGROUND: This study undertakes a systematic and comprehensive analysis of brain gene expression profiles of immune/inflammation-related genes in aging and Alzheimer’s disease (AD). METHODS: In a well-powered microarray study of young (20 to 59 years), aged (60 to 99 years), and AD (74 to 95 years) cases, gene responses were assessed in the hippocampus, entorhinal cortex, superior frontal gyrus, and post-central gyrus. RESULTS: Several novel concepts emerge. First, immune/inflammation-related genes showed major changes in gene expression over the course of cognitively normal aging, with the extent of gene response far greater in aging than in AD. Of the 759 immune-related probesets interrogated on the microarray, approximately 40% were significantly altered in the SFG, PCG and HC with increasing age, with the majority upregulated (64 to 86%). In contrast, far fewer immune/inflammation genes were significantly changed in the transition to AD (approximately 6% of immune-related probesets), with gene responses primarily restricted to the SFG and HC. Second, relatively few significant changes in immune/inflammation genes were detected in the EC either in aging or AD, although many genes in the EC showed similar trends in responses as in the other brain regions. Third, immune/inflammation genes undergo gender-specific patterns of response in aging and AD, with the most pronounced differences emerging in aging. Finally, there was widespread upregulation of genes reflecting activation of microglia and perivascular macrophages in the aging brain, coupled with a downregulation of select factors (TOLLIP, fractalkine) that when present curtail microglial/macrophage activation. Notably, essentially all pathways of the innate immune system were upregulated in aging, including numerous complement components, genes involved in toll-like receptor signaling and inflammasome signaling, as well as genes coding for immunoglobulin (Fc) receptors and human leukocyte antigens I and II. CONCLUSIONS: Unexpectedly, the extent of innate immune gene upregulation in AD was modest relative to the robust response apparent in the aged brain, consistent with the emerging idea of a critical involvement of inflammation in the earliest stages, perhaps even in the preclinical stage, of AD. Ultimately, our data suggest that an important strategy to maintain cognitive health and resilience involves reducing chronic innate immune activation that should be initiated in late midlife

    Product Design: Subassemblies for Multiple Markets

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    A firm may cut costs by installing more parts than its products require. Each product or application requires a specified number of parts such as inductors, resistors and capacitors. For assembly and maintenance reasons, parts are grouped into subassembly modules. If there are economies of scale in manufacturing sub-assembly modules, it may be worthwhile to standardize on a few module designs that will be used in all products or applications even though a few more parts than needed are installed. The cost of giving away extra parts by using few standard modules must be balanced against the fixed costs of producing more types of standard modules. In the multi-market problem there is a fixed cost with the production of a module, and then another fixed cost when the module is used in a market. The paper presents a solution procedure and the time results of computer runs for the problem of finding the best standard modules for a multi-product, multi-market corporation.

    New Alaska Law Will Enhance Nationwide Estate Planning-Part 2

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    The first installment of this two-part article described the portions of Alaska\u27s new legislation that provided for lifetime transfers of IRAs to trusts, strengthened asset protection for trust beneficiaries, asset protection for inherited IRAs, and enacted Alaska\u27s revised decanting statute. This second part of the article focuses on important new procedural and administrative provisions that will facilitate estate planning in Alaska for both residents and nonresidents

    Mangrove seedling net photosynthesis, growth, and survivorship are interactively affected by salinity and light

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    We hypothesized that salinity and light interactively affect mangroves, such that net photosynthesis, growth, and survivorship rates increase more with increase in light availability at low than high salinity. Using greenhouse and field experiments, we determined that net photosynthesis, growth rates, and size increased more with light at low than high salinity. At high salinity, the ratio of leaf respiration to assimilation increased fourfold, suggesting that salinity may have contributed to declines in net photosynthesis. Stomatal conductance, leaf-level transpiration, and internal CO2 concentrations were lower at high salinity. Ratios of root mass to leaf mass were higher at high salinity. Stomatal limitations and increased respiratory costs may explain why at high salinity, the seedlings did not respond to increased light availability with increased net photosynthesis. Increased root mass relative to leaf mass suggests that at high salinity, either water or nutrient limitations may have prevented the seedlings from increasing growth with increasing light availability. At both low- and high-salinity zones in the field, seedling survivorship increased with light availability, and the effect of light was stronger at low salinity. However, at low light, survivorship was higher at high than low salinity, indicating that there may be a trade-off between survivorship and growth. The interactive effects observed in the greenhouse were robust in the field, despite the presence of other factors in the field such as inundation and nutrient gradients and herbivory. This study provides a robust test of the hypothesis that salinity and light interactively effect mangrove seedling performance.</p
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