bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diversity Measures
Authors: Solow A.R. 
Published: September 2006

Abstract

One way in which the term diversity is used in ecology is to characterize the relative abundances of species (or other types) in a community (or other collection of organisms). The relative abundance of a species is defined as the proportion of individual organisms in the community that are of that species. Consider a community containing
s
species. In qualitative terms, the community is said to be diverse if all of the relative abundances are close to 1 /
s
. If all of the relative abundances are equal to 1 /
s
, then the community is said to be even.
Echelon Analysis
Authors: Myers W.L. , Patil G.P. 
Published: September 2006

Abstract

Quantitative spatial data are important inputs for fueling the engines of many environmental models that determine future implications of current resource use, policies, and interventions. End products of applying such models are often mappings of indexes for level of potential environmental impact, which then become guides to allocation of economic and technical resources for amelioration. Errors in quantitative spatial data will propagate through environmental models and find expression in the resulting impact indexes. However, the consequences of such errors for decision‐making may well depend upon where the errors occur. There may be relatively little confusion introduced by moderate errors occurring in a vicinity that otherwise has consistently high values of a variable. In contrast, errors compound confusion in areas that are highly variable. Errors can also substantially distort the apparent state of areas that otherwise have consistently low values of a variable. It is therefore desirable to have a systematic means of determining spatial organization in mappings of quantitative variables, both for input variables to environmental models and for indexes of potential impact generated by the models. Modern computer capabilities for visualization of surfaces are helpful in this regard, but their interpretation is subjective.
Echelons
present an innovative alternative for objectively determining quantitative spatial structure for direct mapping, either with or without computer‐assisted visualization. Thus, they can facilitate analysis of errors associated with environmental models that take quantitative layers as input, or produce quantitative output layers, or both.
Ecosystem
Authors: Kimmins Hamish 
Published: September 2006

Abstract

In common with many other words in the vocabulary of ecology, ‘ecosystem’ is frequently misunderstood. This reflects the short period of a few decades over which this word has been used outside of academic ecology courses, and the lack of knowledge of ecosystem ecology by many who use the word. The word ecosystem was coined in 1935 by the English plant ecologist Tansley. While studying the terrestrial vegetation of the British Isles, he concluded that plant communities can only be understood when considered in the context of the soil, the climate, and the animal and microbial communities with which they are associated. He asserted that vegetation does not exist outside of the ecological system or ecosystem of which it is a part. The science of ecology (from oikos – house or habitat; logos – study of) has been given a variety of definitions that reflect differences in the interests and scientific training of their authors. However, the most complete, yet simplest, definition of ecology is
the study of ecosystems
. Thus, the concept of an ecosystem is the foundation for all branches of ecology, and it is, therefore, important that its meaning is understood.
Ecotoxicology
Authors: Newman Michael C. , Evans David A. 
Published: September 2006

Abstract
Ecotoxicology is the science of contaminants in the biosphere and their effects on constituents of the biosphere. Associated environmetric issues range widely and include those describing contaminant bioaccumulation, trophic transfer, and effects to ecological entities, e.g. individuals, populations, communities, and ecosystems.
Effect Size
Authors: Umbach David M. 
Published: September 2006

Abstract
Broadly construed, effect size is the degree to which one distribution differs from another. While the term itself has connotations of cause and effect, the underlying idea applies to any comparison between two populations without implying causality. Suppose that one seeks to compare two populations with respect to a specified outcome. Regard the populations as a control and an exposed population. The outcome under study will have some distribution across control individuals and, if the exposure has any effect at all, a different distribution among exposed individuals. Differences between the two distributions could be assessed using any one of a number of criteria or even using several criteria simultaneously. A desire for parsimony suggests the use of a single quantity for summarizing distributional differences. Generically, such a quantity assesses the magnitude of the exposure effect, that is, the effect size.
Exact Randomization Technique
Authors: Moir Rob 
Published: September 2006

Abstract

The exact randomization technique is a distribution‐free, computationally‐intensive statistical method of dealing with small samples and uncertain distributions. The technique was first proposed by Fisher in 1935 as a method of dealing with small biological samples. Because of the computational demands, only the recent development of powerful desktop computers permits researchers to regularly use this technique. Suppose two sets of observations are recorded and labeled according to whether they come from a treatment or a control group. The concept of randomization is based on the observation that a conventional test statistic (e.g. a
t
statistic) can be interpreted as a typical draw from the distribution of test statistics that would be generated from randomly shuffling the treatment and control labels among the observed data. In fact, the exact randomization test is essentially a controlled example of bootstrapping.
Fire Risk, Industrial
Authors: Thomas Ian 
Published: September 2006

Abstract
Fire represents both a benefit and a threat to society. Fire is essential and is used constructively in providing many of the materials and services essential to modern living. However, unwanted fires represent a threat that is generally immediately recognized and instils fear into those threatened. Fire generally represents a small but not insignificant risk in modern societies. It represented a greater risk in the past when open fires were common in domestic and industrial situations, but even today unwanted fires are responsible for considerable loss of life, property and services. The consequences of unwanted fires include injuries and death to people and animals involved, loss of contents and building structures and consequential damage to businesses and services. Many of these losses are not recorded, or alternatively, not made publicly available, and so the consequences associated with them are unable to be estimated accurately. However, in many countries considerable effort is expended in recording details of unwanted fires, including locations, causes and consequences. However, international collection of such information is restricted to very basic information such as the overall losses and costs of fires and the number of fire ‐related fatalities per annum.
Forensic Analysis
Authors: Johnson Glenn W. 
Published: September 2006

Abstract
Environmental forensics has been defined as the scientific investigation of criminal or civil offenses against the environment. This broad definition encompasses investigations that run the gamut from arson to poaching to chemical contamination of natural resources. The scientific methods brought to bear in these investigations are also quite broad. In cases of arson, investigators may rely on traditional criminal forensic techniques such as fingerprints and tire tread marks. Poaching investigations increasingly rely on relatively new forensic techniques such as DNA evidence. Chemometric methods are common in environmental forensic investigations, in particular, in cases involving pollutant source allocation. The challenge is to determine how cleanup costs (or in the case of natural resource damage claims, redress costs) will be split among multiple, potentially responsible, parties. Regulatory agencies and potentially responsible parties seldom agree regarding equitable cost‐allocation. Similarly, potentially responsible parties rarely agree among themselves. Each party must make their case to a regulatory agency, an arbitrator, perhaps even a jury. The case inevitably depends on the analysis of huge amounts of environmental chemical data, and that in turn depends on environmental chemometrics.
Forest Inventory
Authors: Scott Charles T. , Gove Jeffrey H. 
Published: September 2006

AbstractForest inventory is an accounting of trees and their related characteristics of interest over a well‐defined land area. It may be compared to census methods for human populations. For example, one of the goals of the periodic decennial census of the US is to enumerate its human population and to retrieve demographic variables such as age, sex and race. This is accomplished by a comprehensive survey of all households in the country. Similarly, forest inventories seek to enumerate the population of trees within a forest and ascertain other information, such as their volume, value, growth and species composition. For all but the smallest tracts of land, complete enumeration of individuals is usually infeasible and survey sampling techniques are required. Unlike human or animal populations, trees are sessile organisms and there is no immigration or emigration to consider. However, tree populations vary widely in their species composition, age, size, site requirements, potential value, longevity and growth – all factors that may influence the design of a forest inventory. In addition, the tree population of interest may exist over a wide variety of topography, making access potentially costly and sometimes even dangerous. Such variety often dictates sampling protocols that may be optimal only for some portion of the population in question. Alternatively, it may call for varying sampling intensity or strategy (the combination of the sampling design and associated estimators) between different regions within the population.
Global Ecology
Authors: Lerdau Manuel 
Published: September 2006

Abstract
Global ecology began with Joseph Priestly's experiments in the eighteenth century demonstrating that plants in effect purified air and thus allowed animals to survive. These results provided the first hard evidence that the activities of some organisms had impacts on the functioning of other organisms at spatial scales greater than that of the individual. More recently, Alfred Redfield demonstrated in the middle of the last century that the structure and behavior of marine organisms played a major role in determining the chemistry of the oceans. In the last 25 years, global ecology has expanded to include a wide range of organismal activities that affect continental and larger spatial scales.
Groundwater Monitoring
Authors: Thornton Steven F. , Lerner David N. , Davison Ruth M. 
Published: September 2006

Abstract
Water that exists below the earth's surface and completely fills pore spaces in the rock strata is termed groundwater. It is estimated that only 0.6% of the total amount of water on the earth is present as groundwater, the majority (97%) being seawater, with the remainder including water trapped in glaciers and polar ice‐caps, present in the atmosphere, and surface freshwater in lakes and rivers. Excluding ice, groundwater represents 97% of nonmarine water, although it is not uniformly distributed and may not be economically usable as a water supply. The proportion of drinking water derived from groundwater resources varies substantially, from only 5% in Norway to 100% in Malta and The Netherlands. This largely reflects the geographical distribution of suitable aquifers from which groundwater can be abstracted and the availability of surface water supplies. Aquifers are those rocks that are sufficiently porous to store water and permeable enough to yield groundwater in economic quantities. The exploitation of groundwater resources requires that the distribution of groundwater in aquifers can be identified and quantified and its quality monitored.
Heritability
Authors: Fry James D. 
Published: September 2006

Abstract
Heritability is a central concept of quantitative genetics, the branch of genetics that deals with the inheritance of continuously‐varying traits. Most traits of agricultural and ecological importance, such as fruit weight or grain yield, are continuous traits. The heritability can be estimated by measuring the degree of resemblance, quantified by the covariance, between relatives of various types.
Interlaboratory Studies
Authors: Vangel Mark G. 
Published: September 2006

Abstract

Interlaboratory studies (sometimes referred to as
collaborative studies
, or
round robins
) are investigations in which measurements are made on one or several materials at several laboratories. These studies are typically conducted for one of three reasons: (i) to evaluate a measurement method; (ii) to evaluate a reference material; or (iii) to evaluate the proficiency of the laboratories themselves.
Litter Effect
Authors: Kupper Lawrence L. 
Published: September 2006

AbstractIt has long been recognized that humans exposed to certain drugs, chemicals, and other environmental hazards may be at increased risk of various health problems. Exposure‐related, adverse, heritable, human health outcomes currently receiving increased attention by public health professionals are fertility and pregnancy complications, birth defects, and developmental abnormalities. Well‐conducted environmental epidemiology studies on human populations would provide the most relevant data for quantifying relationships between exposure levels and adverse pregnancy‐ related outcomes. However, useful information from observational data on humans is often limited in both quantity and quality. So, despite the obvious species‐to‐species extrapolation problem, controlled laboratory experiments on rodents are commonly conducted to provide developmental toxicology data. This article focuses specifically on developmental toxicology studies, where pregnant rodents are exposed to a suspected harmful agent during the period of major fetal organogenesis and structural development. It is well known that an inherent characteristic of data from such rodent teratology studies is the so‐calledlitter effect, i.e. the tendency for littermates all to respond in the same way to stimuli, unlike animals from different litters. Litter effects seem to be present in almost all developmental toxicology studies, and data analyses that do not appropriately account for these litter effects can lead to erroneous statistical inferences.
Matric T‐Distribution
Authors: Sun Li 
Published: September 2006

Abstract

The
t
distribution was first introduced by W.S. Gosset in 1908. Many environmental processes are modeled by
t
instead of Gaussian distributions in order to incorporate uncertainties fully. Successful applications of this kind include air pollution, health impact and epidemiology. A random variable that possesses a
t
distribution can be represented as a ratio of an independent normal and the square root of a χ
2
random variable divided by its degrees of freedom. The degrees of freedom of the χ
2
distribution represent the uncertainty one has about the location of the distribution. In sampling theory, a
t
distribution can be derived from a sample mean and sample variance.
Meta‐Analysis
Authors: Tweedie (deceased June 2001) R.L. 
Published: September 2006

Abstract

The idea of combining information from different studies of the same effect is an old and appealing one. In many areas it has long been common to see reviews of an area, with an expert bringing together the different information and synthesizing a conclusion from many disparate sources. Such overviews often contain qualitative or subjective impressions of the totality of information available, and it was largely in attempts to formalize this approach that the techniques of meta‐analysis have been developed. Meta‐analysis (sometimes called a ‘quantitative synthesis’ or an ‘overview’ is the term used to describe
quantitative
methods for combining information across different studies. It has become particularly popular in situations where the studies individually do not show that an effect is statistically significant.
Model Evaluation and Performance
Authors: Beck B. 
Published: September 2006

Abstract
Whether the behavior of a model matches the behavior of the (real) system–sufficiently well–has always been a matter of great interest. In lay terms, these are the essential questions one would like to have answered in seeking to evaluate a model: (i) has the model been constructed of approved materials, i.e. approved constituent hypotheses (in scientific terms)? (ii) does its behavior approximate well that observed in respect of the real thing? (iii) does it work, i.e. does it fulfill its designated task, or serve its intended purpose?
Transformations, Multivariate
Authors: Ruppert David 
Published: September 2006

AbstractMany of the classical techniques of multivariate analysis, e.g. principal components, factor analysis, canonical correlations, and linear discriminant analysis are based upon the assumption that the data have been sampled from a multivariate normal distribution. These techniques can be quite nonrobust towards some types of deviations from normality, for example heavy‐tails or skewness. When the data deviate from normality, multivariate transformation can re‐express the data as a sample closer to being multivariate normal. In principle, the methodologies developed for transformation to multivariate normality could be used to transform to other multivariate distributions. However, the normal distribution plays such a central role in multivariate analysis that transformation to other multivariate targets has not been considered as important and will not be discussed in this article.
N
ational
R
esources
I
nventory (
NRI
),
US
Authors: Breidt F. Jay 
Published: September 2006

Abstract
The US National Resources Inventory (NRI) is a longitudinal panel survey conducted by the US Department of Agriculture's Natural Resources Conservation Service (formerly the Soil Conservation Service) in cooperation with the Iowa State University Statistical Laboratory. In its current form, the NRI is designed to assess conditions and trends at five year intervals for soil, water, and related natural resources on nonfederal lands of the US. The survey has evolved over a period of several decades, with the specific goal of providing information to support agricultural and environmental policy development and program implementation.
Neurotoxicology, Environmental
Authors: Catalano Paul J. 
Published: September 2006

Abstract
Neurotoxicity testing is an important area of noncancer toxicity evaluation. This article provides a description of the functional observational battery (FOB), a frequently employed neurobehavioral assessment, and discusses some of the statistical and data analytical issues surrounding its analysis. Emphasis is given to describing the multivariate nature of the FOB data.
Occupational Mortality
Authors: Symons Michael J. 
Published: September 2006

AbstractIn studies of mortality of industrial workers, statistical options are limited when: (1) only a few deaths are observed; (2) exposure information at the workplace is nonexistent; (3) personal concomitant exposure data are not available. With none, some, or all of these limitations, the standardized mortality ratio (SMR) is the most frequently used statistic for occupational and environmental cohorts. The SMR is the total number of observed events,O, divided by the total number expected events,E, for those under study. The SMR, as a one‐dimensional summary statistic, is both attractive and limited in scope. It is widely used in mortality studies of industrial populations, serving to screen for excess causes of death and to test for an excess of a specific cause of mortality. A variety of study designs – commonly, proportional mortality, cohort mortality, and case‐control studies – are utilized in the further investigation of hypotheses generated or for more confirmatory tests of results from previous analyses.
Oceanographic Dispersion
Authors: Gargett Ann E. 
Published: September 2006

Abstract
A depth profile taken anywhere in the ocean reveals large vertical gradients of any number of oceanic water properties; for example, temperature, salinity, oxygen concentration, macronutrients such as nitrate and silicate, and micronutrients such as iron. These vertical gradients are formed at the very largest (depth/basin) scales of motion in the sea and eradicated at the very smallest scales, those associated with three‐dimensional turbulence This article first describes the tools presently used to measure and interpret characteristics of the small‐scale ocean processes that result in enhanced vertical diffusion, then reviews various processes known or believed to generate these small scales.
Parallel Computing
Authors: Kulperger Reg , Yu Hao 
Published: September 2006

Abstract
Parallel computing consists of a computing environment connecting many processors. A new technology of distributed processing with a more loose connection between processors is emerging. Both require some special programming methods to take advantage of the connections and communications between processors, but are well suited to certain imaging problems and other statistical problems. This article describes some of the aspects of dealing with these special programming requirements, based on our experience, as statisticians, with such technologies. The types of problems and statistical use of such computing technologies are also discussed. This article is intended to give the reader an overview of the parallel computing environment focusing on the statistical uses that can be made, as opposed to a more detailed computing or engineering description.
Pelagic Ecology
Authors: Reynolds Colin 
Published: September 2006

Abstract

The term ‘pelagic zone’ refers essentially to the open ocean, beyond the continental shelves. However, ‘the pelagic’ is understood by freshwater ecologists to mean simply ‘the open water’ of large lakes and reservoirs. In either instance, the notion of a liquid environment, remote from the shores and bottom of the containing basin, is clear. In extent, the marine pelagic is, by far, the greatest of the world’s major ecosystems, covering some 361 × 10
6
km
2
(or 71% of the planet’s surface) and accommodating an estimated volume of 1.35 × 10
9
km
3
. In contrast, the aggregate volume of the world’s lakes and rivers is a relatively modest 225 × 10
3
km
3
.
Piecewise linear model
Authors: Küchenhoff Helmut 
Published: September 2006

Abstract

In many practical regression‐type problems we cannot fit one uniform regression function to the data, since the functional relationship between the response
Y
and the regressor
X
changes at certain points of the domain of
X
. These points are usually called break points or change points. In such situations, we apply regression models that are obtained by a piecewise definition of the regression function on intervals of the domain of
X
.