924 research outputs found
A Formalism for Management of Surprise or How I Learned to Design Dams and to Hate Systems-Analysis
After many centuries of designing engineering structures and systems within a deterministic framework, it has become fashionable to deal explicitly with uncertainty as an important component of planning and design strategies. Advances in applied statistical decision theory, coupled with the wide availability of computing machinery, are at the root of this transformation, and the recent literature is replete with studies of systems, large and small, under various conditions of uncertainty. This paper deals with a few rules for decision-making under a special category of uncertainty -- namely that associated with the occurrence of events which could not be foretold, let alone assigned a prior probability of realization within a given design horizon
A Proposal for a Decision Framework in the Skane Project
Water resources systems have been an important part of resources and environment related research at IIASA since its inception. As demands for water increase relative to supply, the intensity and efficiency of water resources management must be developed further. This in turn requires an increase in the degree of detail and sophistication of the analysis, including economic, social and environmental evaluation of water resources development alternatives aided by application of mathematical modeling techniques, to generate inputs for planning, design, and operational decisions.
During the year of 1978 it was decided that parallel to the continuation of demand studies, an attempt would be made to integrate the results of our studies on water demands with water supply considerations. This new task was named "Regional Water Management" (Task 1, Resources and Environment Area) . It is concerned with the application of systems analysis techniques for planning and operational management of integrated regional water resources systems.
This paper by Professor M.B. Fiering from Harvard University was drafted during his short visit to IIASA in March 1979. It contains a methodological proposal for analysis of regional water resources management. A model which couples alternative water demand patterns with the long-term availability of water is formulated
Mathematical Models for Screening
In this Report, another screening method in the design of water resource systems -- termed the Effective Capacity Method, or Method II -- is suggested. As in Method I, the Equivalent Reservoir Method (May 1973), this again uses the equivalent capacity concept, but here the equivalent capacities downstream of the entire system, termed effective capacities, are calculated for each potential reservoir individually. The cost-capacity functions for each site are modified to cost-effective capacity functions and the required system storage is allocated on the basis of these modified cost functions
Management and Standards for Perturbed Ecosystems
This paper introduces some new constructs for measuring the effectiveness of environmental standards and for formalizing the economic and social costs of meeting them. It emphasizes the element of recovery time (and of its manipulation) in ecosystem management, and thereby lays the mathematical foundation for further study of an Environmental Zoo (a physical entity in which living organisms are stocked to replenish depleted numbers in the field) and for evaluation of long-term exposure to low-level pollutants. The biological models presented here are taken directly from Holling, whose work distinguishes importantly between the properties of "stability" and "resilience", and who is continuing even now to apply these concepts to management of the spruce budworm in the province of New Brunswick. In place of conclusions, this paper identifies a few potentially fruitful programs for further work
A nongenomic mechanism for progesterone-mediated immunosuppression: Inhibition of K+ channels, Ca2+ signaling, and gene expression in T lymphocytes
The mechanism by which progesterone causes localized suppression of the immune response during pregnancy has remained elusive. Using human T lymphocytes and T cell lines, we show that progesterone, at concentrations found in the placenta, rapidly and reversibly blocks voltage-gated and calcium-activated K+ channels (KV and KCa, respectively), resulting in depolarization of the membrane potential. As a result, Ca2+ signaling and nuclear factor of activated T cells (NF-AT)-driven gene expression are inhibited. Progesterone acts distally to the initial steps of T cell receptor (TCR)-mediated signal transduction, since it blocks sustained Ca2+ signals after thapsigargin stimulation, as well as oscillatory Ca2+ signals, but not the Ca2+ transient after TCR stimulation. K+ channel blockade by progesterone is specific; other steroid hormones had little or no effect, although the progesterone antagonist RU 486 also blocked KV and KCa channels. Progesterone effectively blocked a broad spectrum of K+ channels, reducing both Kv1.3 and charybdotoxin-resistant components of KV current and KCa current in T cells, as well as blocking several cloned KV channels expressed in cell lines. Progesterone had little or no effect on a cloned voltage-gated Na+ channel, an inward rectifier K+ channel, or on lymphocyte Ca2+ and Cl- channels. We propose that direct inhibition of K+ channels in T cells by progesterone contributes to progesterone-induced immunosuppression
First-order reliability method for estimating reliability, vulnerability, and resilience
Reliability, vulnerability, and resilience provide measures of the frequency, magnitude, and duration of the failure of water resources systems, respectively. Traditionally, these measures have been estimated using simulation. However, this can be computationally intensive, particularly when complex system-response models are used, when many estimates of the performance measures are required, and when persistence among the data needs to be taken into account. In this paper, an efficient method for estimating reliability, vulnerability, and resilience, which is based on the First-Order Reliability Method (FORM), is developed and demonstrated for the case study of managing water quality in the Willamette River, Oregon. Reliability, vulnerability, and resilience are determined for different dissolved oxygen (DO) standards. DO is simulated using a QUAL2EU water quality response model that has recently been developed for the Oregon Department of Environmental Quality (ODEQ) as part of the Willamette River Basin Water Quality Study (WRBWQS). The results obtained indicate that FORM can be used to efficiently estimate reliability, vulnerability, and resilience.Holger R. Maier, Barbara J. Lence, Bryan A. Tolson, and Ricardo O. Fosch
Genomic imprinting variations in the mouse type 3 deiodinase gene between tissues and brain regions.
The Dio3 gene, which encodes for the type 3 deiodinase (D3), controls thyroid hormone (TH) availability. The lack of D3 in mice results in tissue overexposure to TH and a broad neuroendocrine phenotype. Dio3 is an imprinted gene, preferentially expressed from the paternally inherited allele in the mouse fetus. However, heterozygous mice with paternal inheritance of the inactivating Dio3 mutation exhibit an attenuated phenotype when compared with that of Dio3 null mice. To investigate this milder phenotype, the allelic expression of Dio3 was evaluated in different mouse tissues. Preferential allelic expression of Dio3 from the paternal allele was observed in fetal tissues and neonatal brain regions, whereas the biallelic Dio3 expression occurred in the developing eye, testes, and cerebellum and in the postnatal brain neocortex, which expresses a larger Dio3 mRNA transcript. The newborn hypothalamus manifests the highest degree of Dio3 expression from the paternal allele, compared with other brain regions, and preferential allelic expression of Dio3 in the brain relaxed in late neonatal life. A methylation analysis of two regulatory regions of the Dio3 imprinted domain revealed modest but significant differences between tissues, but these did not consistently correlate with the observed patterns of Dio3 allelic expression. Deletion of the Dio3 gene and promoter did not result in significant changes in the tissue-specific patterns of Dio3 allelic expression. These results suggest the existence of unidentified epigenetic determinants of tissue-specific Dio3 imprinting. The resulting variation in the Dio3 allelic expression between tissues likely explains the phenotypic variation that results from paternal Dio3 haploinsufficiency.This is the final version of the article. It is available from the Endocrine Society in Molecular Endocrinology here: http://press.endocrine.org/doi/pdf/10.1210/me.2014-1210
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