Hospital site selection using fuzzy AHP and its derivatives

Environmental managers are commonly faced with sophisticated decisions, such as choosing the location of a new facility subject to multiple conflicting criteria. This paper considers the specific problem of creating a well-distributed network of hospitals that delivers its services to the target population with minimal time, pollution and cost. We develop a Multi-Criteria Decision Analysis process that combines Geographical Information System (GIS) analysis with the Fuzzy Analytical Hierarchy Process (FAHP), and use this process to determine the optimum site for a new hospital in the Tehran urban area. The GIS was used to calculate and classify governing criteria, while FAHP was used to evaluate the decision factors and their impacts on alternative sites. Three methods were used to estimate the total weights and priorities of the candidate sites: fuzzy extent analysis, center-of-area defuzzification, and the b1;-cut method. The three methods yield identical priorities for the five alternatives considered. Fuzzy extent analysis provides less discriminating power, but is simpler to implement and compute than the other two methods. The b1;-cut method is more complicated, but integrates the uncertainty and overall attitude of the decision-maker. The usefulness of the new hospital site is evaluated by computing an accessibility index for each pixel in the GIS, defined as the ratio of population density to travel time. With the addition of a new hospital at the optimum site, this index improved over about 6.5 percent of the geographical area.     

PATTERNS OF PERIPHYTON CHLOROPHYLL α IN AN AGRICULTURAL NONPOINT SOURCE IMPACTED STREAM1

ABSTRACT: An agricultural nonpoint source polluted stream in northern Idaho was examined to determine seasonal and longitudinal patterns of periphyton chlorophyll α. Chlorophyll a was measured at eight sites along Lapwai Creek, a fifth order stream impacted by agricultural runoff containing nutrients and eroded soils. Seasonally, periphyton chlorophyll α was lowest in the spring (cumulative x?= 60.4 mg m^?2) and highest in the summer (cumulative x?= 222 mg m^?2). Winter concentrations were higher than expected (cumulative x?= 168.6 mg m^?2). The headwaters, flowing through an open grassy meadow, had the lowest concentrations of the study (two-year x?= 49.7 mg m^?2). Immediately below a small, eutrophic reservoir, periphyton chlorophyll α increased markedly (two-year x?= 155.8 mg m^?2) and remained high through a deep canyon (two year x?= 135.5 mg m^?2) and down to the mouth of the stream (two-year x?= 172.3 mg^?2). Periphyton chlorophyll α in Lapwai Creek was at least two times greater than values reported in the literature for comparable, undisturbed Idaho streams. We suggest that increased nutrient concentrations via agricultural nonpoint source pollution and increased light penetration from the removal of large, woody riparian vegetation have resulted in high periphyton chlorophyll α along the continuum of Lapwai Creek.     

Determination of the aerobic biodegradability of polymeric material in a laboratory controlled composting test

A laboratory method is presented for investigating the biodegradation of an organic test material in an aerobic composting system based on the evolution of carbon dioxide. In addition to carbon conversion, biodegradation can also be monitored through weight loss and physical disintegration. The test method is different from other biodegradation tests, especially aquatic tests, because of the elevated temperature representative for real composting conditions and also because of enhanced fungal degradation activities. A ring test was run using paper and poly-b2;-hydroxybutyrate/valerate as test materials and cellulose powder as a reference material. The test results and the experience gained by the participants showed that the method is suitable and practicable. Experience with real technical-scale composting facilities confirms that the method provides test results of high predictive value. The test is designed to become a European Standard in connection with determining the compostability of packagings and packaging materials.     

Effects of temperature and precipitation on grassland bird nesting success as mediated by patch size

Grassland birds are declining faster than any other bird guild across North America. Shrinking ranges and population declines are attributed to widespread habitat loss and increasingly fragmented landscapes of agriculture and other land uses that are misaligned with grassland bird conservation. Concurrent with habitat loss and degradation, temperate grasslands have been disproportionally affected by climate change relative to most other terrestrial biomes. Distributions of grassland birds often correlate with gradients in climate, but few researchers have explored the consequences of weather on the demography of grassland birds inhabiting a range of grassland fragments. To do so, we modeled the effects of temperature and precipitation on nesting success rates of 12 grassland bird species inhabiting a range of grassland patches across North America (21,000 nests from 81 individual studies). Higher amounts of precipitation in the preceding year were associated with higher nesting success, but wetter conditions during the active breeding season reduced nesting success. Extremely cold or hot conditions during the early breeding season were associated with lower rates of nesting success. The direct and indirect influence of temperature and precipitation on nesting success was moderated by grassland patch size. The positive effects of precipitation in the preceding year on nesting success were strongest in relatively small grassland patches and had little effect in large patches. Conversely, warm temperatures reduced nesting success in small grassland patches but increased nesting success in large patches. Mechanisms underlying these differences may be patch‐size‐induced variation in microclimates and predator activity. Although the exact cause is unclear, large grassland patches, the most common metric of grassland conservation, appears to moderate the effects of weather on grassland‐bird demography and could be an effective component of climate‐change adaptation.     

Ecological consequences of forest elephant declines for Afrotropical forests

Poaching is rapidly extirpating African forest elephants (Loxodonta cyclotis) from most of their historical range, leaving vast areas of elephant‐free tropical forest. Elephants are ecological engineers that create and maintain forest habitat; thus, their loss will have large consequences for the composition and structure of Afrotropical forests. Through a comprehensive literature review, we evaluated the roles of forest elephants in seed dispersal, nutrient recycling, and herbivory and physical damage to predict the cascading ecological effects of their population declines. Loss of seed dispersal by elephants will favor tree species dispersed abiotically and by smaller dispersal agents, and tree species composition will depend on the downstream effects of changes in elephant nutrient cycling and browsing. Loss of trampling and herbivory of seedlings and saplings will result in high tree density with release from browsing pressures. Diminished seed dispersal by elephants and high stem density are likely to reduce the recruitment of large trees and thus increase homogeneity of forest structure and decrease carbon stocks. The loss of ecological services by forest elephants likely means Central African forests will be more like Neotropical forests, from which megafauna were extirpated thousands of years ago. Without intervention, as much as 96% of Central African forests will have modified species composition and structure as elephants are compressed into remaining protected areas. Stopping elephant poaching is an urgent first step to mitigating these effects, but long‐term conservation will require land‐use planning that incorporates elephant habitat into forested landscapes that are being rapidly transformed by industrial agriculture and logging.     

Incorporating fragmentation and non‐native species into distribution models to inform fluvial fish conservation

Fluvial fishes face increased imperilment from anthropogenic activities, but the specific factors contributing most to range declines are often poorly understood. For example, the range of the fluvial‐specialist shoal bass (Micropterus cataractae) continues to decrease, yet how perceived threats have contributed to range loss is largely unknown. We used species distribution models to determine which factors contributed most to shoal bass range loss. We estimated a potential distribution based on natural abiotic factors and a series of currently occupied distributions that incorporated variables characterizing land cover, non‐native species, and river fragmentation intensity (no fragmentation, dams only, and dams and large impoundments). We allowed interspecific relationships between non‐native congeners and shoal bass to vary across fragmentation intensities. Results from the potential distribution model estimated shoal bass presence throughout much of their native basin, whereas models of currently occupied distribution showed that range loss increased as fragmentation intensified. Response curves from models of currently occupied distribution indicated a potential interaction between fragmentation intensity and the relationship between shoal bass and non‐native congeners, wherein non‐natives may be favored at the highest fragmentation intensity. Response curves also suggested that >100 km of interconnected, free‐flowing stream fragments were necessary to support shoal bass presence. Model evaluation, including an independent validation, suggested that models had favorable predictive and discriminative abilities. Similar approaches that use readily available, diverse, geospatial data sets may deliver insights into the biology and conservation needs of other fluvial species facing similar threats.     

Quantifying nonuse and indirect economic benefits of impingement & entrainment reductions at U.S. power plants

Monetizing ecological benefits of reducing impingement and entrainment (I&E) at cooling water intake structures presents both ecological and economic challenges. Ecological challenges arise because it is difficult to demonstrate and measure these impacts. Economic challenges arise because of these ecological uncertainties and because many of the potentially affected ecosystem services cannot be valued using traditional methods. Under a recently promulgated U.S. regulation certain power generation and industrial water permit applicants may be required to monetize these “nonuse” benefits. However, stated preference (SP) surveys, the only method available for valuing nonuse services have not seen acceptance by mainstream economists. This paper describes an approach to valuation that incorporates the ecological service function approach advocated by the USEPA Science Advisory Board to characterize impacts. Data and models are used to quantify, to the extent possible, direct and indirect impacts of I&E on ecosystem services. Nonuse values are then estimated by an SP survey that measures respondents’ willingness to pay for reducing I&E. Methods are proposed for calibrating and validating results including identifying the source of nonuse values from commonly ascribed motivations (i.e. existence, bequest, altruistic), considering the role of pre-survey awareness of impacts, and evaluating results in the context of respondent willingness to pay for other nonuse benefits.     

Measuring the radium-226 activity using a multidetector γ-ray coincidence spectrometer

BиccCb;oвaнияx вoэмocy;жнocтeф пpимeн eния мeтoдoв coвaдeниф дффeктив нoгo cхeтa иэиuхaтeCb;eф пoхитpoнoв в б oCb;ьщиx oбpaэцax, pнpимeня жидкocт нDb;ф cцинтCb;Cb;яциoннDb;ф cхeтхик 4π дCb;я вceгo, cocтoяшиф иэ 2-x дeтeктocy;pнDb;x кaмep 2π. Пpeждe вceгo иэuхaCb;ocв oбpaэoвaниe фoн a, кaк oтвeтнaя peaция в мeтoдe co coвпaдeниф. B peэuCb;втaтe импuCb;вcoв coвпaдeни ф в oбoиx дeтeктopнDb;x кaмepax нaбCb;ю энaхитeCb;внDb;ф uхacтoк фoнa. ИэuхaCb;acvcy; пoдaвCb;eни я фoнa пuтa cхeтa пueтa cхeтa aнт иcoвпaдeнeниф, нo этoт мeтoд нe oкaэaCb;cя uCb;я uCb;u oхDb;хнDb;x гaммa-иэCb;ucy;хaтaeCb;eф. oднaк o, в cCb;нaяx, кoгпa в oбpaэцax coдepж aCb;иcв тaкиe иэCb;uхaтeCb;и пoэитpoнoв, кaк ²²Na и ⁵⁸ co, фoн мoжнo бDb;Cb;o энaхитeCb;внo пoд aвитв и cхeтнuю cтaтиcтикu нa нa мнoгo юCb; юхшитв пpимeняя пpимeняя cпoco бDb; Db; coвпaдeниф. Этoт мeтoд нe тoдвкo uмeнвщaeт фoн, нo тaкиe мoнoгaмм-иэCb;uхaтeCb;и, кaк ¹³⁷Cs ⁴⁰К. Taким oбким oбpaэoм, этoт мeт oд нaпpaшивaeтcя caм coбoф дCb;я иэ peния иэCb;uхaтeCb;eф пoэитpoнoв в хeCb;oвeкe, гдe ¹³⁷Cs ⁴⁰К п pиcuтcтвuют, кaк интepфиpuюшиф фoн:.

Zusammenfassung

Ein 4π-Flüssigkeits-“Ganzkörper”-Szintillationszähler, bestehend aus 2π-Detektrortanks wurde dazu verwendet, die mögliche Anwendung von Koinzidenzarbeitsweisen zur wirksamen Zählung von Positronenemittern in grossen Proben zu studieren. Zunächst wurde die Hintergrundemp-findlichkeit für die Koinzidenzform untersucht. Man beobachtete, dass ein ansehnlicher Teil des Hintergrundes von Impulsen in der Koinzidenz in beiden Detektortanks herrührte. Die Möglichkeit einer Unterdrückung des Hintergrundes durch Antikoinzidenzzählung wurde erforscht, aber dies stellte sich als unbrauchbar für eine Verbesserung der Zählstatistik zum Zählen gewöhnlicher Gammaemitter heraus. Wenn die Proben jedoch Positronenemitter wie ²²Na and ⁵⁸Co enthalten, so könnte der Hintergrund weitgehend unterdrückt und die Zählstatistik beträchtlich verbessert werden, wenn man Koinzidenzzählverfahren anwendet. Das Verfahren verminderte nicht nur den Hintergrund, sondern es diskriminierte auch gegenüber solchen Monogammaemittern wie ¹³⁷Cs und ⁴⁰K. Das Verfahren eignet sich somit zur Messung von Positronenemittern im Menschen, wo ¹³⁷Cs und ⁴⁰K als “Störhintergrund” zugegen sind.