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Time-series Data (time-sery + data)
Selected AbstractsFreshwater invasions: using historical data to analyse spreadDIVERSITY AND DISTRIBUTIONS, Issue 1 2007Sarina E. Loo ABSTRACT Aquatic invasive species cause deleterious environmental and economic impacts, and are rapidly spreading through ecosystems worldwide. Despite this, very few data sets exist that describe both the presence and the absence of invaders over long time periods. We have used Geographical Information Systems (GIS) to analyse time-series data describing the spread of the freshwater invasive New Zealand mudsnail, Potamopyrgus antipodarum, in Victoria, Australia, over 110 years. We have mapped the snail's spread, estimated the percentage of stream length invaded through time, calculated the functional form of the spread rate, and investigated the role that the two proposed vectors , fish stocking and angling , have had in this invasion. Since it was first found in 1895, P. antipodarum has expanded its range in Victoria and now occurs throughout much of the southern and central areas of the state. The north of the state is relatively less invaded than the south, with the division corresponding approximately to the presence of the Great Dividing Range. We show that the snail's range has been increasing at an approximately exponential rate and estimate that 20% of total Victorian stream length is currently invaded. We also show that using long-term data can change the outcome of analyses of the relationship between vectors of spread and invasion status of separate catchments. When our time-series data were aggregated through time, the total numbers of fish stocking events and angling activity were both correlated with invasion. However, when the time-series data were used and the number of fish stocking events calculated up until the date of invasion, no relationships with stocking were found. These results underline the role that time-series data, based on both presences and absences, have to play when investigating the spread of invasive species. [source] Potential impacts on the incidence of fatal heroin-related overdose in Western Australia: a time-series analysisDRUG AND ALCOHOL REVIEW, Issue 4 2002KIM HARGREAVES Abstract In response to the rising concerns about the rate of heroin-related fatalities, overdose prevention campaigns, run by both users' organizations and government agencies, have been implemented in a number of states across Australia. In Western Australia (WA) in mid-1997, various overdose prevention initiatives were implemented. These included the implementation of a protocol limiting police presence at overdose events; the commencement of naloxone administration by ambulance staff; and the establishment of the Opiate Overdose Prevention Strategy (OOPS) which provided follow-up for individuals treated for overdose in emergency departments. This paper reports the results of a multiple linear regression analysis of 60 months of time-series data, both prior to and following the implementation of these interventions, to determine their impact on the number of fatal heroin overdoses in WA. The model employed in the analysis controlled for changes over time in proxy indicators of use and community concerns about heroin, as well as market indicators. The results suggest that, although the interventions implemented have managed to reduce the expected number of fatalities, they have become less successful in doing so as time passes. This has implications for both existing and potential interventions to reduce fatal heroin-related overdose. [source] Minimum viable population sizes and global extinction risk are unrelatedECOLOGY LETTERS, Issue 4 2006Barry W. Brook Abstract Theoretical and empirical work has shown that once reduced in size and geographical range, species face a considerably elevated risk of extinction. We predict minimum viable population sizes (MVP) for 1198 species based on long-term time-series data and model-averaged population dynamics simulations. The median MVP estimate was 1377 individuals (90% probability of persistence over 100 years) but the overall distribution was wide and strongly positively skewed. Factors commonly cited as correlating with extinction risk failed to predict MVP but were able to predict successfully the probability of World Conservation Union Listing. MVPs were most strongly related to local environmental variation rather than a species' intrinsic ecological and life history attributes. Further, the large variation in MVP across species is unrelated to (or at least dwarfed by) the anthropogenic threats that drive the global biodiversity crisis by causing once-abundant species to decline. [source] Bootstrap Methods for Markov ProcessesECONOMETRICA, Issue 4 2003Joel L. Horowitz The block bootstrap is the best known bootstrap method for time-series data when the analyst does not have a parametric model that reduces the data generation process to simple random sampling. However, the errors made by the block bootstrap converge to zero only slightly faster than those made by first-order asymptotic approximations. This paper describes a bootstrap procedure for data that are generated by a Markov process or a process that can be approximated by a Markov process with sufficient accuracy. The procedure is based on estimating the Markov transition density nonparametrically. Bootstrap samples are obtained by sampling the process implied by the estimated transition density. Conditions are given under which the errors made by the Markov bootstrap converge to zero more rapidly than those made by the block bootstrap. [source] A Reality Check for Data SnoopingECONOMETRICA, Issue 5 2000Halbert White Data snooping occurs when a given set of data is used more than once for purposes of inference or model selection. When such data reuse occurs, there is always the possibility that any satisfactory results obtained may simply be due to chance rather than to any merit inherent in the method yielding the results. This problem is practically unavoidable in the analysis of time-series data, as typically only a single history measuring a given phenomenon of interest is available for analysis. It is widely acknowledged by empirical researchers that data snooping is a dangerous practice to be avoided, but in fact it is endemic. The main problem has been a lack of sufficiently simple practical methods capable of assessing the potential dangers of data snooping in a given situation. Our purpose here is to provide such methods by specifying a straightforward procedure for testing the null hypothesis that the best model encountered in a specification search has no predictive superiority over a given benchmark model. This permits data snooping to be undertaken with some degree of confidence that one will not mistake results that could have been generated by chance for genuinely good results. [source] The Role of Political Instability in Stock Market Development and Economic Growth: The Case of GreeceECONOMIC NOTES, Issue 3 2000Dimitrios Asteriou This article examines empirically the relationship between stock market development, political instability and economic growth in Greece. We measure socio-political instability by constructing an index which captures the occurrence of various phenomena of political violence using time-series data. The main advantages of analysing political instability in a case study framework using time-series, in contrast with the widely used cross-country empirical studies, are: (a) a more careful and in-depth examination of institutional and historical characteristics of a particular country; (b) the use of a data set comprised of the most appropriate and highest quality measures; and (c) a more detailed exposition of the dynamic evolution of the economy. The empirical results indicate the existence of a strong negative relationship between uncertain socio-political conditions and the general index of the Athens Stock Exchange (ASE) and support the theoretical hypothesis that uncertain socio-political conditions affect economic growth negatively, is true for the Greek case. (J.E.L.: G10, G14, O40, C32) [source] Bivariate distributed lag models for the analysis of temperature-by-pollutant interaction effect on mortalityENVIRONMETRICS, Issue 3 2007Vito M. R. Muggeo Abstract This paper introduces Bivariate Distributed Lags Models (BDLMs) to investigate synergic effect of temperature and airborne particles on mortality. These models seem particulary attractive since they allow to model interactions between such environmental variables accounting for possible delayed effects. A B-spline framework is used to approximate the coefficient surface of the temperature-by-pollutant interaction and possible alternatives are also discussed. A case study of mortality time-series data in Palermo, Italy, is presented to illustrate the model. Copyright © 2007 John Wiley & Sons, Ltd. [source] Detecting intrusion transactions in databases using data item dependencies and anomaly analysisEXPERT SYSTEMS, Issue 5 2008Sattar Hashemi Abstract: The purpose of the intrusion detection system (IDS) database is to detect transactions that access data without permission. This paper proposes a novel approach to identifying malicious transactions. The approach concentrates on two aspects of database transactions: (1) dependencies among data items and (2) variations of each individual data item which can be considered as time-series data. The advantages are threefold. First, dependency rules among data items are extended to detect transactions that read or write data without permission. Second, a novel behaviour similarity criterion is introduced to reduce the false positive rate of the detection. Third, time-series anomaly analysis is conducted to pinpoint intrusion transactions that update data items with unexpected pattern. As a result, the proposed approach is able to track normal transactions and detect malicious ones more effectively than existing approaches. [source] Diving behavior of immature, feeding Pacific bluefin tuna (Thunnus thynnus orientalis) in relation to season and area: the East China Sea and the Kuroshio,Oyashio transition regionFISHERIES OCEANOGRAPHY, Issue 3 2004Takashi Kitagawa Abstract Twenty-four archival tags were recovered from Pacific bluefin tuna previously released off Tsushima Island in the East China Sea. By analysis of the time-series data of the pressure and the ambient and internal temperature from the 24 tags, we examined the relationship between the tuna's pattern of diving and the thermocline depth. In the East China Sea, diving and feeding events occurred throughout almost the entire day in both winter and summer, suggesting that the purpose of diving is for feeding. In summer, the feeding frequency was greater than that in winter, which corresponds to the fact that growth is more rapid in summer than in winter. During summer in the Kuroshio,Oyashio transition region, on the other hand, feeding events were much more frequent than those in the East China Sea, in spite of a lower diving frequency. The mean horizontal distance traveled was also significantly higher and it seems that in this area they may move horizontally to feed on prey accumulated at the surface. We conclude that, in addition to the ambient temperature structure, the vertical and horizontal distribution of prey species plays an important role in the feeding behavior of Pacific bluefin tuna. One bluefin tuna migrated to the Oyashio frontal area, where both the horizontal and the vertical thermal gradients are much steeper. The fish spent most of the time on the warmer side of the front and often traveled horizontally to the colder side during the day, perhaps to feed. This implies that there is a thermal barrier effect, in this case from the Oyashio front, on their behavior. The frequency of feeding events was low, although all the monitored fish dived every dawn and dusk, irrespective of the seasons or location. It is possible that these twice-daily diving patterns occurred in response to the change in ambient light at sunrise and sunset. [source] Tourism demand modelling: some issues regarding unit roots, co-integration and diagnostic testsINTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 5 2003Paresh Kumar Narayan Abstract This paper investigates the all important issue of diagnostic tests, including unit roots and cointegration, in the tourism demand modelling literature. The origins of this study lie in the apparent lack in the tourism economics literature of detail concerning the diagnostic test aspect. Study of this deficiency has suggested that previous literature on tourism demand modelling may be divided into two categories: the pre-1995 and post-1995 studies. It was found that the pre-1995 and some post-1995 studies have ignored unit root tests and co-integration and, hence, are vulnerable to the so-called ,spurious regression' problem. In highlighting the key diagnostic tests reported by post-1995 studies, this paper contends that there is no need to report the autoregressive conditional heteroskedasticity (ARCH) test, which is applicable only to financial market analysis where the dependent variable is return on an asset. More generally, heteroskedasticity is not seen as a problem in time-series data. However, the reporting of a greater than necessary range of diagnostic tests,,,some of which do not have any theoretical justification with regard to tourism demand analysis,,,does not diminish the precision of the results or the model. This paper should appeal to scholars involved in tourism demand modelling. Copyright © 2003 John Wiley & Sons, Ltd. [source] Nonstationary spatio-temporal small rodent dynamics: evidence from long-term Norwegian fox bounty dataJOURNAL OF ANIMAL ECOLOGY, Issue 3 2009John-André Henden Summary 1The geographical pattern in Fennoscandian small rodent population dynamics with a southern noncyclic and a northern cyclic region, and with latitudinal gradients in density-dependent structure, cycle period length and spatial synchrony within the northern cyclic region, has been widely publicized and interpreted in the ecological literature. However, the time-series data on which these inferences have been established are relatively short and originate from a specific time period (mostly around 1970,90). Hence, it can be questioned whether the geographical population dynamics patterns are consistent over time (i.e. whether they are stationary). 2Here we analyse an almost century long (1880,1976) panel of fox bounty time series including 18 counties of Norway, thus spanning the whole range of latitudes of Fennoscandia (i.e. 15 latitudinal degrees). These fox time series mirror the dynamics of their dominant small rodent prey, in particular, with respect to cycle period length and spatial synchrony. 3While we found some evidence consistent with previous analyses showing a clearly patterned dynamics according to latitude, such patterns were not stationary on a longer time-scale. In particular, we observed a shift from an extensively synchronous (i.e. regionalized) 4-year cycle north of 60°N just after the ,Little Ice Age' (1880,1910) to a diversification of cycle period length (3,5 years) and eventually, partial loss of cyclicity and synchronicity in later periods. Incidents of loss of cyclicity appeared to be preceded by changes in cycle period (i.e. period lengthening and shortening). 4These results show that the dynamics of Fennoscandian small rodents, and their associated guild of predators, are more prone to change than previously acknowledged. [source] Numerical fluctuations in the northern short-tailed shrew: evidence of non-linear feedback signatures on population dynamics and demographyJOURNAL OF ANIMAL ECOLOGY, Issue 2 2002Mauricio Lima Summary 1,We studied a fluctuating population of the northern short-tailed shrew (Blarina brevicauda) in the Appalachian Plateau Province of Pennsylvania, USA, spanning 21 years of monitoring. We analysed the pattern of annual temporal variation fitting both time-series models and capture,mark,recapture (CMR) statistical models for survival and recruitment rates. 2,We determined that non-linear first-order models explain almost 80% of the variation in annual per capita population growth rates. In particular, a non-linear self-excited threshold autoregressive (SETAR) model describes the time-series data well. Average snowfall showed positive and non-linear effects on population dynamics. 3,The CMR statistical models showed that a non-linear threshold model with strong effects of population density was the best one to describe temporal variation in survival rates. On the other hand, population density or climatic variables did not explain temporal variation in recruitment rates. Survival rates were high during the study period. Weekly changes in population size attributable to new recruits entering in the population fluctuate between 21% and 0%, while the changes in population size related to survival fluctuate between 79% and 100%. 4,Two important results arise from this study. First, non-linear models with first-order feedback appear to capture the essential features of northern short-tailed shrew dynamics and demography. Secondly, climate effects represented by snowfall appear to be small and non-linear on this insectivore. The population dynamics of this shrew in the Appalachian Plateau are determined apparently by a strong non-linear first-order feedback process, which is related to survival rates. 5,This study links population dynamics and demography by detecting the underlying demographic mechanisms driving population dynamics. The feedback structure of this shrew suggests the existence of population dynamics dominated by intraspecific competitive interactions, such as aggression, solitary nesting, non-overlapping home ranges and territoriality. [source] Learning, forecasting and structural breaksJOURNAL OF APPLIED ECONOMETRICS, Issue 5 2008John M. Maheu We provide a general methodology for forecasting in the presence of structural breaks induced by unpredictable changes to model parameters. Bayesian methods of learning and model comparison are used to derive a predictive density that takes into account the possibility that a break will occur before the next observation. Estimates for the posterior distribution of the most recent break are generated as a by-product of our procedure. We discuss the importance of using priors that accurately reflect the econometrician's opinions as to what constitutes a plausible forecast. Several applications to macroeconomic time-series data demonstrate the usefulness of our procedure. Copyright © 2008 John Wiley & Sons, Ltd. [source] Clustering multivariate time-series dataJOURNAL OF CHEMOMETRICS, Issue 8 2005Ashish Singhal Abstract A new methodology for clustering multivariate time-series data is proposed. The new methodology is based on calculating the degree of similarity between multivariate time-series datasets using two similarity factors. One similarity factor is based on principal component analysis and the angles between the principal component subspaces while the other is based on the Mahalanobis distance between the datasets. The standard K -means clustering algorithm is modified to cluster multivariate time-series datasets using similarity factors. Simulation data from two nonlinear dynamic systems: a batch fermentation and a continuous exothermic chemical reactor, are clustered to demonstrate the effectiveness of the proposed technique. Comparisons with existing clustering methods show several advantages of the proposed method. Copyright © 2006 John Wiley & Sons, Ltd. [source] Valuing food-borne risks using time-series data: The case of E. coli O157:H7 and BSE crises in JapanAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 2 2006Shunji Oniki This study evaluates changes in consumers' concerns on food safety after the outbreaks of E. coli O157 and bovine spongiform encephalopathy (BSE) in Japan using household consumption time-series data. A food demand system for Japanese households is estimated using the linear approximate almost-ideal demand system (AIDS) model to evaluate the willingness to accept (WTA) compensation for risk. The Kalman filtering method is applied to produce estimates without a priori assumption regarding timing of the changes. The WTA value rises immediately after a food safety crisis occurs and declines in a short time. However, it does not return to previous levels for an extended period. A possible explanation for remaining effects of a crisis might be that they are the results of habit formation and learning effects of consumption. [EconLit citations: D12, D18, Q13]. © 2006 Wiley Periodicals, Inc. Agribusiness 22: 219,232, 2006. [source] Aid heterogeneity: looking at aid effectiveness from a different angleJOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 8 2005George Mavrotas The paper uses an aid disaggregation approach to examine the impact of different aid modalities on the fiscal sector of the aid-recipient country. It uses time-series data on different types of development aid (project aid, programme aid, technical assistance and food aid) for Uganda, an important aid recipient in recent years, to estimate a model of fiscal response in the presence of aid which combines aid heterogeneity and endogenous aid. The empirical findings clearly suggest the importance of the above approach for delving deeper into aid effectiveness issues since different aid categories have different effects on key fiscal variables,an impact that could not be revealed if a single figure for aid were employed. Project and food aids appear to cause a reduction in public investment whereas programme aid and technical assistance are positively related to public investment. The same applies for government consumption. A negligible impact on government tax and non-tax revenues, and a strong displacement of government borrowing are also found. Copyright © 2005 John Wiley & Sons, Ltd. [source] Nonmarital Fertility and the Effects of Divorce Rates on Youth Suicide RatesJOURNAL OF MARRIAGE AND FAMILY, Issue 4 2006Steven F. Messner Using pooled, time-series data for a sample of 15 developed nations, we assess the effect of divorce rates on gender-specific suicide rates for youths aged 15 , 19 with models of relative cohort size, lagged nonmarital fertility, and an interaction term for divorce rates and nonmarital fertility. The results reveal that, for young men, relative cohort size is positively related to suicide rates, and divorce rates interact with lagged nonmarital fertility. The interaction effect indicates that increases in divorces are especially consequential for suicide cohorts of male youths who were born in periods of high nonmarital fertility. For female youths, only divorce rates exert a significant effect on suicide rates, and it is a positive, main effect. [source] Photometry of cometary nuclei: rotation rates, colours and a comparison with Kuiper Belt Objects,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006C. Snodgrass ABSTRACT We present time-series data on Jupiter Family Comets (JFCs) 17P/Holmes, 47P/Ashbrook-Jackson and 137P/Shoemaker-Levy 2. In addition we also present results from ,snap-shot' observations of comets 43P/Wolf-Harrington, 44P/Reinmuth 2, 103P/Hartley 2 and 104P/Kowal 2 taken during the same run. The comets were at heliocentric distances of between 3 and 7 au at this time. We present measurements of size and activity levels for the snap-shot targets. The time-series data allow us to constrain rotation periods and shapes, and thus bulk densities. We also measure colour indices (V,R) and (R,I) and reliable radii for these comets. We compare all of our findings to date with similar results for other comets and Kuiper Belt Objects (KBOs). We find that the rotational properties of nuclei and KBOs are very similar, that there is evidence for a cut-off in bulk densities at ,0.6 g cm,3 in both populations, and the colours of the two populations show similar correlations. For JFCs, there is no observational evidence for the optical colours being dependent on either position in the orbit or orbital parameters. [source] A Disparity of Esteem: Relative Group Status in Northern Ireland after the Belfast AgreementPOLITICAL PSYCHOLOGY, Issue 1 2007Roger Mac Ginty Using the case of a deeply divided society (Northern Ireland) in the aftermath of a major peace accord, this article combines two methodological approaches to assess the public reception of the peace accord and its impact on intergroup competition. The social psychological concept of esteem (central to social identity theory) and time-series data are used to assess intergroup relations between Protestant-unionists and Catholic-nationalists in Northern Ireland in the wake of the 1998 peace accord. By illustrating the disparity of esteem between the two main politico-religious groups, the article indicates early settlement weakness. Moreover, it suggests a conceptual approach that may be applicable to the study of intergroup competitions in other divided societies. [source] The Role of Uncertainty in Investment: An Examination of Competing Investment Models Using Commercial Real Estate DataREAL ESTATE ECONOMICS, Issue 1 2000A. Steven Holland Neoclassical investment decision criteria suggest that only the systematic component of total risk affects the rate of investment, as channeled through the built-asset price. Alternatively, option-based investment models suggest a direct role for total uncertainty in investment decisionmaking. To sort out uncertainty's role in investment, we specify and empirically estimate a structural model of asset-market equilibrium. Commercial real estate time-series data with two distinct measures of asset price and uncertainty are used to assess the competing investment models. Empirical results generally favor predictions of the option-based model and hence suggest that irreversibility and delay are important considerations to investors. Our findings also have implications for macroeconomic policy and for forecasts of cyclical investment activity. [source] Comparative Analysis of Ownership Transformation and Performance Relationship among Major and Regional Banks in AustraliaTHE AUSTRALIAN ECONOMIC REVIEW, Issue 2 2006Kandiah Jegasothy This article attempts to clarify existing doubts with respect to the performance of private and privatised banks versus public banks; that is, it is an attempt to clarify the ownership,performance relationship. The analysis takes explicit account of the privatisation transformation, including its intermediary stage, and the status of the economy. The ownership,performance model is estimated using cross-sectional time-series data and is used to test the influence of ownership changes on performance. Alternative performance measures are considered. The empirical findings show that ownership transformation in the case of regional banks has resulted in improved performance, whilst the benefits in the case of major banks were not significant, even though these banks have become more competitive. [source] The Dynamics of Political Attention: Public Opinion and the Queen's Speech in the United KingdomAMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 4 2009Will Jennings This article represents the effect of public opinion on government attention in the form of an error-correction model where public opinion and policymaking attention coexist in a long-run equilibrium state that is subject to short-run corrections. The coexistence of policy-opinion responsiveness and punctuations in political attention is attributed to differences in theoretical conceptions of negative and positive feedback, differences in the use of time series and distributional methods, and differences in empirical responsiveness of government to public attention relative to responsiveness to public preferences. This analysis considers time-series data for the United Kingdom over the period between 1960 and 2001 on the content of the executive and legislative agenda presented at the start of each parliamentary session in the Queen's Speech coded according to the policy content framework of the U.S. Policy Agendas Project and a reconstituted public opinion dataset on Gallup's "most important problem" question. The results show short-run responsiveness of government attention to public opinion for macroeconomics, health, and labor and employment topics and long-run responsiveness for macroeconomics, health, labor and employment, education, law and order, housing, and defense. [source] Treating Words as Data with Error: Uncertainty in Text Statements of Policy PositionsAMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 2 2009Kenneth Benoit Political text offers extraordinary potential as a source of information about the policy positions of political actors. Despite recent advances in computational text analysis, human interpretative coding of text remains an important source of text-based data, ultimately required to validate more automatic techniques. The profession's main source of cross-national, time-series data on party policy positions comes from the human interpretative coding of party manifestos by the Comparative Manifesto Project (CMP). Despite widespread use of these data, the uncertainty associated with each point estimate has never been available, undermining the value of the dataset as a scientific resource. We propose a remedy. First, we characterize processes by which CMP data are generated. These include inherently stochastic processes of text authorship, as well as of the parsing and coding of observed text by humans. Second, we simulate these error-generating processes by bootstrapping analyses of coded quasi-sentences. This allows us to estimate precise levels of nonsystematic error for every category and scale reported by the CMP for its entire set of 3,000-plus manifestos. Using our estimates of these errors, we show how to correct biased inferences, in recent prominently published work, derived from statistical analyses of error-contaminated CMP data. [source] MACROECONOMIC PERFORMANCE AND INEQUALITY: BRAZIL, 1983,94THE DEVELOPING ECONOMIES, Issue 1 2009Manoel BITTENCOURT D31; E31; O11; O54 We examine how poor macroeconomic performance, mainly in terms of high rates of inflation, affected earnings inequality in the 1980s and early 1990s in Brazil. The results, based initially on aggregate time series, and then on sub-national panel time-series data and analysis, show that the extreme inflation, combined with an imperfect process of financial adaptation and incomplete indexation coverage, had a regressive and significant impact on inequality. The implication of the results is that sound macroeconomic policies, which keep inflation low and stable in the long run, should be a necessary first step of any policy package implemented to alleviate inequality in Brazil. [source] EXPORT-LED GROWTH IN CHILE: ASSESSING THE ROLE OF EXPORT COMPOSITION IN PRODUCTIVITY GROWTHTHE DEVELOPING ECONOMIES, Issue 3 2006Dierk HERZER O47; F43; C22 This study examines the export-led growth hypothesis using annual time-series data from Chile in a production function framework. It addresses the limitations of the existing literature and focuses on the impact of manufactured and primary exports on productivity growth. In order to investigate if and how manufactured and primary exports affect economic growth via increases in productivity, several single-equation and system cointegration techniques are applied. The estimation results can be interpreted as evidence of productivity-enhancing effects of manufactured exports and of productivity-limiting effects of primary exports. [source] EMPIRICAL IMPACT OF PUBLIC INFRASTRUCTURE ON THE JAPANESE ECONOMY,THE JAPANESE ECONOMIC REVIEW, Issue 4 2008CHRISTOPHER N. ANNALA We study the impact of public capital investment on individual sectors of the Japanese economy using time-series data for the period of 1970,1998. We employ a production function approach and also estimate a dynamic VAR/ECM model. We find significant differences in the employment effects, output effects and private investment effects across sectors. Public capital investment has a positive effect on employment in the finance, insurance and real estate (FIRE), manufacturing, construction and utilities sectors; on private investment in the FIRE, agriculture, transportation, trade and services sectors; and on output in the mining, FIRE, trade and manufacturing sectors. [source] How to Determine the Number of Relations Among Deterministic TrendsTHE JAPANESE ECONOMIC REVIEW, Issue 3 2000Michio Hatanaka Hatanaka (1998a) showed that the number of relations between deterministic trends of different variables played an important role in empirical studies of macroeconomic theories. In the present paper two methods are presented to determine the number from the time-series data. The one investigates eigenvalues of the data covariance matrix on a parametric model of trends accommodating interrelationships. The other analyses OLS residuals on the basis of a looser concept of interrelated trends. JEL Classification Numbers: C32, C50. [source] Mapping tree species in temperate deciduous woodland using time-series multi-spectral dataAPPLIED VEGETATION SCIENCE, Issue 1 2010R. A. Hill Abstract Questions: What is the optimum combination of image dates across a growing season for tree species differentiation in multi-spectral data and how does species composition affect overstorey canopy density? Location: Monks Wood, Cambridgeshire, eastern England, UK. Methods: Six overstorey tree species were mapped using five Airborne Thematic Mapper images acquired across the 2003 growing season (17 March, 30 May, 16 July, 23 September, 27 October). After image pre-processing, supervised maximum likelihood classification was performed on the images and on all two-, three-, four- and five-date combinations. Relationships between tree species composition and canopy density were assessed using regression analyses. Results: The image with the greatest tree species discrimination was acquired on 27/10 when the overstorey species were in different stages of leaf tinting and fall. In this image, tree species were mapped with an overall classification accuracy (OCA) of 71% (kappa 0.63). A similar OCA was achieved from the other four images combined (OCA 72%, kappa 0.64). The highest classification accuracy was achieved by combining three images: 17 March, 16 July, 27 October. This achieved an OCA of 84% (kappa 0.79), increasing to 88% (kappa 0.85) after a post-classification clump and sieve procedure. Canopy height and percentage cover of oak explained 72% of variance in canopy density. Conclusions: The ability to discriminate and map temperate deciduous tree species in airborne multi-spectral imagery is increased using time-series data. An autumn image supplemented with an image from both the green-up and full-leaf phases was optimum. The derived tree species map provides a more powerful ecological tool for determining woodland structural/compositional relationships than field-based measures. [source] | |||||||||||||||||||||||||||||||