bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of fire regimen on two species of epiphytic orchids in tropical savannas of the Northern Territory
Authors: COOK G. D. 
Published: July 2006

AbstractThe effect of four fire regimens (early dry season annual, late dry season annual, early dry season biennial, unburnt) on the numbers of epiphytic orchids in a savanna community in Kakadu National Park was investigated. These fire regimens had been maintained on I ha plots for 16 years. Two species of epiphytic orchid were present — Cymbidium canaliculatum and Dendrobium affine. The numbers of Cymbidium plants were insufficient to enable statistical analysis, but plants were present in the unburnt, early annual and early biennial fire treatments. Dendrobium occurred in substantial numbers irrespective of fire treatment, but the extent of colonization of all available host trees was greater in the unburnt than the burnt treatments.The lower numbers of Dendrobium plants in burnt treatments was due to a lower proportion of potential host trees being colonized and a lower number of orchids on each colonized tree. The proportion of small trees colonized was markedly lower in burnt treatments. Frequent fires late in the dry season may prevent recruitment of the main host species. Eucalyptus tectifica. The survival of orchids despite frequent fires depended on the availability of relatively protected sites for colonization and the ability of the orchids to withstand some fire damage.
Soil temperatures during bushfires in semi‐arid, mallee shrublands
Authors: BRADSTOCK R. A. , Auld T. D. , ELLIS M. E. , Cohn J. S. 
Published: July 2006

Abstract
Soil temperatures were measured during 11 experimental fires in semi‐arid mallee shrublands in central NSW. Sensors were placed at depths from 1–10 cm beneath the soil surface in three fuel types; litter beneath Eucalyptus shrubs, live hummocks of the grass Triodia irritans and litter beneath shrubs of Acacia species. Weights of these fuels per unit area were determined.Maximum soil temperature and its duration were related to fuel type and depth. Mean weights of Eucalyptus and Triodia fuels were similar (0.35 kg m−2), while there was less Acacia fuel (0.1 kg m−2). Highest maximum temperatures were registered under Eucalyptus litter (e.g. 140°C at 2 cm). Maximum temperatures under Triodia and Acacia litter were similar (e.g. 60–70°C at 2 cm). Durations were examined in two temperature classes (60–120 and > 120°C) chosen to represent threshold for stimulation of germination and mortality, respectively, of soil‐stored seeds. Temperatures between 60 and 120°C were recorded only between 0–2 cm soil depth for Acacia and Triodia (one exception at 4 cm). No temperatures >120°C were recorded for these fuel types. Temperatures between 60 and 120°C were recorded to 5 cm depth under Eucalyptus fuels while putative lethal temperatures for seeds occurred occasionally at 0–2 cm depth.The results indicated greatest potential for stimulation of germination and death of buried seeds under Eucalyptus fuels, although the level of variability of temperature was highest under Eucalyptus fuels. Despite similar fuel loads, differences between temperatures under Eucalyptus and Triodia fuels reflected the influence of the depth of the fuel bed, with Triodia hummocks constituting a deep fuel bed and Eucalyptus litter a shallow fuel bed.
Links between ecology and ecophilosophy, ethics and the requirements of environmental management
Authors: FAIRWEATHER P. G. 
Published: July 2006

Abstract
This paper concerns the ways that our philosophical attitudes to the environment can influence the appropriateness of methodologies for solving environmental problems. Sometimes a public perception is expressed that science takes scant regard of the concerns of the people affected. Is it possible for scientists and managers to respond to such concerns and still fulfil the logical and methodological rigour that their discipline demands? I believe we have to address fundamental issues of definitions and meaning before useful debate can occur among parties interested in environmental decision‐making. Delving into the ideas behind our everyday practices of environmental management should promote re‐evaluation of our beliefs, attitudes and concerns about nature.I examine environmental science from both ethical and managerial perspectives. I explore how our assumptions and attitudes might influence ecology, in particular issues raised by environmental impacts and conservation. The major points argued here are:

Any legal requirements of environmental investigations must be met, but perhaps we should act more in line with the spirit of legislation.
The managerial imperatives of environmental investigations need to be examined closely because of widely perceived problems with the use of science in impact assessment. We must change either our methods of assessment or the regulations and administration of environmental impact assessment (EIA).
Science is not paramount in the processes of environmental decision‐making. We need to be aware of how psychosocial factors affect the ultimately political decisions about environmental problems.
Philosophy and ethics offer a range of perspectives that may benefit ecology. Scientists need to be aware of these just as they should be of their own leanings about how we treat nature.
Scientists need to translate social concerns or demands about the environment into properly defined scientific questions, and then study them as a matter of urgency.
Ecology needs to guide ecophilosophers and environmental ethicists as to how nature works, why we expect variability in ecosystems, what is naturalness, and other issues where a scientific understanding of nature has progressed beyond the point where these observers of ecology have so far taken inspiration.
An assessment of the colonizing ability of Emex australis
Authors: PANETTA F. D. , RANDALL R. P. 
Published: July 2006

Abstract
Experimental introductions of the annual Emex australis were made in two consecutive years at each of three sites in southern Western Australia. Introductions differed in relation to the numbers of seeds involved (n = 1, 2,4, 8 or 16) and whether seeds were buried or surface sown. Fates of the introductions were monitored for 30 months. Successful introductions were defined as those where at least one viable seed was produced. Generally, introduction success increased with the number of seeds involved and with seed burial. However, major departures from these trends were observed at one site in the second set of introductions.Most recruitment and most seed production occurred during the first growing season following introduction. The number of seeds produced over the 30 month period usually increased with increasing size of introduction. The year of introduction was a highly significant determinant of seed production. Since seedling mortality was low throughout this study, processes affecting seed burial and seed mortality are considered to be the major stochastic factors that influence the colonizing success of Emex australis.
Detection of mining impacts on aquatic macroinvertebrate communities: Results of a disturbance experiment and the design of a multivariate BACIP monitoring programme at Coronation Hill, Northern Territory
Authors: FAITH D. P. , DOSTINE P. L. , HUMPHREY C. L. 
Published: July 2006

Abstract
Multivariate methods for the detection of impacts on communities are: (i) explored in the context of a disturbance experiment at a site of previous uranium mining in Kakadu National Park, Northern Territory; and (ii) applied to the design of a monitoring programme for a proposed mining development at nearby Coronation Hill. The disturbance experiment in Rockhole Mine Creek used a gravity‐fed redirection of polluted water from the mine adit to create a point‐source pollutant. Weekly samples of the macroinvertebrate communities were taken both before and after disturbance at the control and‘impact’ site, as part of a multivariate BACIP (Before‐After‐Control‐Impact‐Pairs) design. The results of the experiment show that the multivariate approach provided high sensitivity in detecting impacts on the community, with little difference in sensitivity between species and family level analyses. A simple procedure for deleting those taxa that show poor discrimination between pristine and presently disturbed areas further increased the sensitivity of the tests. In addition to the BACIP analyses, robust ordination of the community data suggested a time/treatment interaction effect.Application of the multivariate BACIP approach also was explored using baseline data for benthic communities from the South Alligator River near Coronation Hill. The method provides high statistical power for monitoring; a relatively small change in community dissimilarity would be detectable in a programme with 5 years of observations before and after commencement of mining. A robust ordination of the yearly samples for the control and potential‐impact sites showed that, although samples varied along identifiable gradients over time, the two areas changed in parallel so that the difference between the areas was approximately constant over years. This result demonstrates that the multivariate BACIP approach can provide relative constancy of pre‐impact difference values, a key requirement of BACIP designs that is difficult to satisfy using abundance data for a single species.
POPULATION'S URBAN ENVIRONMENT EVALUATION MODEL AND ITS APPLICATION*
Authors: Maeda Hiroshi , Murakami Shuta 
Published: July 2006

ABSTRACTWe propose the Population's Urban Environment Evaluation Model that quantitatively presents inhabitants’ evaluations of urban environments. Our target is to establish firmly a method to effectively reflect the inhabitants’ consciousness in a regional planning process. The approach taken follows a group decision‐making theory and a multi‐attribute utility theory: a kind of social welfare function (of additive form) is identified by using questionnaire data. The results of application of our model to Kitakyushu show that it presents several useful insights for regional planning.
ON THE SENSITIVITY OF GRAVITY MODEL FORECASTS*
Authors: Weber James S. , Sen Ashish K. 
Published: July 2006

ABSTRACTIn this paper we present a procedure for estimating small changes in gravity model forecasts in response to small changes in input values (trip end totals and/or parameter values). The procedure can be used to derive covariance matrices from which confidence intervals may be obtained and which may be used for tests of hypotheses. While this type of problem has been addressed by others, our approach is the only one that is conveniently applicable to the doubly constrained model and can accommodate the large numbers of origin and destination zones one typically encounters.
TESTING SIZE‐DENSITY RELATIONSHIPS WITHOUT RATIO‐VARIABLES, MULTICOLLINEARITY, LOGARITHMIC TRANSFORMATIONS, OR REGRESSION ANALYSIS*
Authors: Stephan G. Edward , Dorman Dan 
Published: July 2006

ABSTRACTUsing data describing the historical distribution of county seats in the United States, we (1) replicate the traditional ratio‐variable test of the size‐density law, (2) test a new multivariate, nonratio form of the law, and (3) introduce an alternative method of testing, one which avoids three possible problems in traditional analyses: ratio‐variables, multicollinearity, and logarithmic transformation.
A PROPERTY OF THE RANK‐SIZE DISTRIBUTION AND ITS USE IN AN URBAN HIERARCHY CONTEXT
Authors: Beguin Hubert 
Published: July 2006

ABSTRACTThis paper proves the symmetry of the classical rank‐size distribution with respect to any city according to a criterion of relative population difference. This property is used to characterize the distribution of city sizes around the median center of their hierarchical level by the existence of symmetry, of an upper bound to dispersion, and of a regular spacing. An interpretation is suggested.
INTERDEPENDENT BEHAVIOR WITH RELOCATION COSTS: THE COMPARATIVE STATICS OF SPATIAL HISTORY*
Authors: Clapp John M. 
Published: July 2006

ABSTRACTRelocation costs are a form of sunk costs because they are relevant to new entrants, not to agents at their existing locations. With sufficiently high relocation costs, initial (historically given) locations and other conditions determine the equilibrium assignment of agents to locations. Comparative static results depend on initial conditions, i.e., history matters and historical persistence can be characterized.The model suggests empirically‐relevant results which can be tested by collecting data on relocation and transportation costs. For example, appropriate levels of these costs imply that suburbanization always occurs with the entry of new firms. Sequential entry strategies may be adopted by existing firms which earn pure profits. This may be contrasted with traditional NUE models which predict changes in the boundaries of central zones.
REGIONAL GROWTH IN THE SOVIET ECONOMY A MODEL AND ANALYSIS*
Authors: Kushnirsky F. I. 
Published: July 2006

ABSTRACTA multiregional econometric model of the Soviet economy is presented. It consists of 1,391 equations, with time‐series information for 1965‐1980. In conformity with the number of the country's republics, 15 input‐output tables are incorporated. The discussion includes the methodological framework, the structure and equations, theoretical justification for the interaction between the econometric and input‐output components, data and estimation, and forecasting results.
LOCATIONAL FACTORS IN THE DECLINING INDUSTRIAL COMPETITIVE ADVANTAGE OF THE NEW YORK URBAN REGION*
Authors: Tran Dang T. 
Published: July 2006

ABSTRACTThis paper investigates the locational factors that contributed to the decline of the New York urban region's industries during 1972‐1975. Based on the static concept of a specialization index, a dynamic comparative advantage index is constructed. A model is then formulated to test the hypothesis that regional competitive advantage (vis‐à‐vis the nation) is a function of relative disparities in the change of these locational factors. Regression results show that the region's competitive advantage is influenced positively by the differential rate of change in market size, by the differential profit rate before tax, and negatively by the differential rate of change in unit labor cost and in unit energy cost. The differential tax rate does not seem to affect the region's competitive advantage. Nevertheless, a progressive corporate income tax structure tends to neutralize the beneficial effects of the economies of agglomeration and the urban attraction of the region.
SPATIAL DISEQUILIBRIUM
Authors: Thore Sten 
Published: July 2006

ABSTRACT. The well‐known extremal principle for the solution of spatial equilibrium for a single commodity [Samuelson (1952)] is extended to deal with the case of disequilibrium caused by rigid prices and/or price controls. Both disequilibrium in consumer markets and in factor markets is covered.The study of disequilibrium is well known in general interdependent economic systems (the so‐called fixed‐price model of interdependent systems). The present work extends this approach to the spatial dimension, and shows how it is possible to represent and solve disequilibrium models by mathematical programming rather than by fixed‐point techniques.
A PRACTICAL NOTE ON THE NEOCLASSICAL ECONOMIC‐BASE MARGINAL MULTIPLIER*
Authors: Merrifield John 
Published: July 2006

ABSTRACTComputation and usage of my neoclassical economic‐base marginal multiplier formula (Merrifield, 1987) is simplified. The note points out the economic parameters that must be estimated with some care and for which rough approximations suffice. It also indicates when the size of the multiplier will be significantly affected by the source of the exogenous stimulus (factor‐ or output‐price change). The traditional bifurcation effort must be supplemented with careful estimates of only a small subset of the other parameters. For most of the simulated parameter combinations, the multiplier based on exogenous factor‐price changes differed from the multiplier based on output‐price changes by less than 10 percent.
A DEMOGRAPHIC ANALYSIS OF THE POPULATION GROWTH OF STATES, 1950‐1980*
Authors: Smith Stanley K. , Ahmed Bashir 
Published: July 2006

ABSTRACTState populations in the United States are characterized by large differences in current growth rates and historical growth trends. What demographic factors account for these differences? Population growth has only three components: births, deaths, and migration. In this study, we estimated the contributions of births, deaths, and migration to changes in population size between 1950 and 1980 for the 48 contiguous states in the United States. We found that population momentum (i.e., the growth that would occur in a closed population if fertility and mortality rates remained constant) had the largest effect on population growth in most states, but that differences in net migration were the major cause of state‐to‐state differences in growth rates. We also found that net migration has been gaining in importance compared to natural increase as a component of population growth. We expect this trend to continue in coming decades.
SPATIAL COMPETITION AND THE JOINT CONSUMPTION OF SERVICES*
Authors: Ohsawa Yoshiaki 
Published: July 2006

ABSTRACTIn Hotelling location models, an implicit assumption has been made that a customer uses the service provided by the firm, independent of other customers. However, for firms that supply meeting rooms, wedding halls, tennis courts, and golf links it is essential to incorporate the fact that the customer only uses the service in conjunction with other customers. The objective of this paper is to formulate the Hotelling location model n consideration of the interdependence among customers in one‐dimensional space, and to characterize the state of equilibrium. In our model, each group of members within a given distance enjoys a fixed amount of service of the firms, under the assumption that the travel cost incurred by each group is defined as the travel cost of the farthest customer in the group.
SERIAL CORRELATION IN MULTIREGIONAL MIGRATION MODELS*
Authors: Foot David K. , Milnet William J. 
Published: July 2006

ABSTRACTIn this paper, we outline the specification and estimation of a time series of multiregional net‐migration equations subject to first‐order serial correlation. We show that the necessary nonstochastic adding‐up constraint, which requires that net migration in the system sum to zero, imposes restrictions on the serial‐correlation coefficients. We estimate equations under these restrictions using data for the ten Canadian provinces for the period 1962‐1985. The results confirm the significance of the serial‐correlation coefficient and, hence, the importance of incorporating this correction in future time‐series models of multiregional migration.
TARIFF PROTECTION IN AN OPEN SPATIAL ECONOMY*
Authors: Hatzipanayotou Panos , Heffley Dennis 
Published: July 2006

ABSTRACTSpatial pricing models have been used to illustrate a tariff's asymmetric effects on consumers located at different points in the protected economy, and to demonstrate that the optimum tariff for a small open spatial economy may be positive. In these models, the distribution of households has been taken as uniform and fixed.We extend the spatial model by allowing households to optimally locate and consume variable amounts of land, as well as the domestic‐ or foreign‐produced good. Land consumption, location rents, and the distribution of consumers are endogenous, responding to tariff‐induced changes in the delivered prices of the domestic and foreign goods. Within this limited general equilibrium framework, a neoclassical result resurfaces: from the perspective of private consumers, the optimum tariff in a small open economy is zero. The possibility of a positive optimum tariff, however, may remain intact in a more integrated model where domestic profits and tariff revenues are redistributed within the spatial economy.
AN ECONOMIC INTERPRETATION OF KUHN'S DUAL FOR THE STEINER‐WEBER PROBLEM A NOTE*
Authors: Guccione Antonio , Gillen William J. 
Published: July 2006

ABSTRACTIn this paper, we given an economic interpretation of Kuhn's dual of the Steiner‐Weber problem. It depends essentially on the notion that different transportation systems arerelevant for the primal and the dual. Moreover, the Euclidean metric underlies the interpretation of the primal, the block one that of the dual.
A HIERARCHIAL OPTIMIZATION PROCEDURE FOR MAGROECONOMIC POLICY MODELS
Authors: Krouse Clement G. 
Published: July 2006

AbstractAn area of difficulty in the effective application of econometric models to determine optimal macroeconomic policy is the specification of the welfare functional. In such models it is required to synthesize a scalar‐valued criterion which properly relates tho joint effects of various economic factors. This paper develops a systematic procedure for treating (his problem when the several variables of the criterion are set forth in preference by a lexicographic ordering. In capsule, the procedure gives sequential attention to the various factors, with the constraint set at a given optimization stage determined by the characteristics of the solution at all prior stages.
INTERTEMPORAL OPTIMIZATION IN AN AGRARIAN MODEL WITH Z‐ACTIVITIES*
Authors: Bautista Romeo M. 
Published: July 2006

AbstractThis paper examines the optimal characteristics of an agrarian growth model in which two production activities are distinguished, viz., one producing the usual agricultural (consumption) goods F, and the other consisting of labor‐using Z‐activities directed toward substitute consumption for industrial goods and augmentation of agricultural capital.Certain restrictive assumptions on the form of the utility function are made which reflect in part the nature of the three types of consumption goods being distinguished. Optimum conditions are derived using classical calculus of variations, yielding additional variables in the form of shadow prices. Non‐negativity of gross investment is shown to be the only relevant boundary constraint and is accordingly taken into account in the analysis. The phase diagram involving the capital‐labor ratio and the shadow price of Z‐goods indicates that the unique stationary point is a saddle‐point. Some segment of the two stable branches then represents the interior solution to the infinite horizon problem; if the initial capital‐labor ratio is ≪ sufficiently high ≫, the optimal path will entail zero gross investment in the initial phase. Where the period of optimization is finite, different patterns of optimum capital accumulation and valuation will emerge, depending on the initial and terminal values of the capital‐labor ratio. Two cases are illustrated, the optimal path in each being shown to exhibit the turnpike property.It follows that optimal growth may be achieved by directly controlling the rate of capital accumulation or by having the planning authority set the shadow price of Z‐goods. Other means of optimization are in fact available, e.g., controlling imports of industrial consumption goods. That one policy instrument is sufficient to attain the single objective is consistent with the well‐known proposition in the theory of economic policy.
ON THE STABILITY OF OLIGOPOLY WITH NONDOGMATIC CONJECTURES
Authors: Tarr David G. 
Published: July 2006

AbstractIn recent years a number of authors have considered a variety of expectations assumptions in analyzing the stability of oligopoly. In this paper it is assumed that an oligopolist has a probability distribution for its competitors'outputs. This ≪ nondogmatic conjectures ≫ approach enables us to determine: (1) which of the stability results are not dependent on the expectation assumption made and (2) how the expectation assumptions themselves affect the stability results.