bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recovering precision from seemingly redundant rounded data
Authors: Collier Irwin L. , Baltagi Badi H. 
Published: July 2007

AbstractEconomic time series from the socialist economies of Eastern Europe and the Soviet Union are often not available. Instead, a matrix of rounded growth indexes for different base years is published. Using the constrained least squares and feasible GLS estimators developed in this paper, it is possible to predict the true matrix of growth indexes with greatly improved accuracy.
Parameter sensitivities, monte carlo filtering, and model forecasting under uncertainty
Authors: Rose Kenneth A. , Smith Eric P. , Gardner Robert H. , Brenkert Antoinette L. , Bartell Steven M. 
Published: July 2007

AbstractComplex models are often used to make predictions of environmental effects over a broad range of temporal and spatial scales. The data necessary to adequately estimate the parameters of these complex models are often not available. Monte Carlo filtering, the process of rejecting sets of mode! simulations that fail to meet prespecified criteria of model performance, is a useful procedure for objectively establishing parameter values and improving confidence in model predictions. This paper uses a foodweb model to examine the relationship between model sensitivities and Monte Carlo filtering. Results show that Monte Carlo filtering with a behavior definition that is closely related to the sensitivity structure of the model will produce substantial reductions in model forecasting uncertainty.
Simultaneous equation estimates of electricity demand for the rural south: Revenue projection when prices are administered
Authors: McKean John R. , Winger Wendell D. 
Published: July 2007

AbstractPresented are estimates of demand equations and producer revenue projections for rural farm electricity consumers in the USA. Statistical tests include a Box‐Cox comparison of functional form, a Koyck‐distributed lag, and a contrast of average versus marginal prices. Producer revenue projections take account of the estimated demand equation and non‐continuous rate schedules for each of the electricity distributors. Multiple price equilibria result from differences in administered price schedules between sellers. The ‘effective’ price elasticity based upon forecasts which take account of the market circumstances is lower than the simple demand point elasticity but higher than found in some previous studies.
Temporal aggregation and systematic sampling in structural time‐series models
Authors: González Pilar 
Published: July 2007

AbstractGiven a structural time‐series model specified at a basic time interval, this paper deals with the problems of forecasting efficiency and estimation accuracy generated when the data are collected at a timing interval which is a multiple of the time unit chosen to build the basic model. Results are presented for the simplest structural models, the trend plus error models, under the assumption that the parameters of the model are known. It is shown that the gains in forecasting efficiency and estimation accuracy for having data at finer intervals are considerable for both stock and flow variables with only one exception. No gain in forecasting efficiency is achieved in the case of a stock series that follows a random walk.
Analysis and forecasting of income statement account balances the dynamic interdependency and ARIMA approaches
Authors: Lin Winston T. 
Published: July 2007

AbstractThis paper develops a dynamic simultaneous‐equations model for analyzing and forecasting the account balances in the income statement of a firm. In the model, the income statement accounts play the role of the dependent variables that are jointly determined and explained by three types of exogenous variables: non‐controllable, performance, and controllable. The model is estimated by the three‐stage least‐squares method using annual series of data for six firms during the period from 1936 or 1950 to 1981. The immediate, delayed, and cumulated impacts of an exogenous shock on the income accounts are analyzed and the implications for managerial decisions and strategies discussed. To run as a standard of comparison for the dynamic interdependency model, the Box‐Jenkins approach is also used to develop an autoregressive integrated moving average (ARIMA) model for each of the accounts. Assessing the forecasting performance of the dynamic model against a naive model and the ARIMA and Elliott‐Uphoff models for the 1982‐4 period beyond the estimation period, we conclude that the dynamic model is a better representation of income statement accounts of the firm and increases forecasting accuracy.
Modelling the world economy: The european perspective
Authors: Artis M. , Holly S. 
Published: July 2007

AbstractIn this paper we provide a short description of the major developments in multi‐country modelling, and then identify where we believe models of the world economy need to develop further in order to be better able to capture interdependencies among national economies, and to address the central policy dilemmas created by the evolution of the world economy over the next decade. We then examine the policy implications of the simulations that the five modelling groups carried out.
Algorithms for explaining forecast revisions
Authors: Todd Richard M. 
Published: July 2007

AbstractForecasts are routinely revised, and these revisions are often the subject of informal analysis and discussion. This paper argues (1) that forecast revisions are analyzed because they help forecasters and forecast users to evaluate forecasts and forecasting procedures and (2) that these analyses can be sharpened by using the forecasting model to systematically express its forecast revision as the sum of components identified with specific subsets of new information, such as data revisions and forecast errors. An algorithm for this purpose is explained and illustrated.
Minimum variance prediction of bilinear time series: Direct and adaptive versions
Authors: Bielińska Ewa M. 
Published: July 2007

AbstractBilinear models of time series are considered. Minimum variance predictor for bilinear time series, homogeneous in the input and output, is proposed. Results of minimum variance prediction of bilinear time series are included. They are compared to the results of linear prediction of bilinear time series.A minimum variance prediction algorithm for bilinear time series of the general form is developed and an adaptive version of minimum variance algorithm is derived.
An envelope function model for forecasting athletics records
Authors: Dargahi‐Noubary G. R. 
Published: July 2007

AbstractThe purpose of this paper is to present a multiplicative model for the fastest time per year in the 400‐ and 800‐metre races. It is composed of an envelope function and a stationary time series. The proposed model is plausible since there is dependency between the fastest times of successive years and because improvements are expected to be smaller now, as compared with several years ago. Data from the years 1860 to 1988 are used for illustration.
Forecasting load‐duration curves
Authors: Bruce Andrew , Jurke Simon , Thomson Peter 
Published: July 2007

AbstractA new method is proposed for forecasting electricity load‐duration curves. The approach first forecasts the load curve and then uses the resulting predictive densities to forecast the load‐duration curve. A virtue of this procedure is that both load curves and load‐duration curves can be predicted using the same model, and confidence intervals can be generated for both predictions. The procedure is applied to the problem of predicting New Zealand electricity consumption. A structural time‐series model is used to forecast the load curve based on half‐hourly data. The model is tailored to handle effects such as daylight savings, holidays and weekends, as well as trend, annual, weekly and daily cycles. Time‐series methods, including Kalman filtering, smoothing and prediction, are used to fit the model and to achieve the desired forecasts of the load‐duration curve.
Testing for unreliable estimators and insignificant forecasts in combined forecasts
Authors: Chandrasekharan Radha , Moriarty Mark M. , Wright Gordon P. 
Published: July 2007

AbstractThe reliability and precision of the weights used in combining individual forecasts, irrespective of the method of combination, is important in evaluating a combined forecast. The objective of this study is not to suggest the ‘best’ method of combining individual forecasts, but rather to propose exploratory procedures, that make use of all available sample information contained in the covariance matrix of individual forecast errors, to (1) detect if the weights used in combining forecasts are ‘reliable’ (and ‘stable’ if it is known that the covariance matrix of forecast errors is stationary over time) and (2) test for ‘insignificant’ individual forecasts used in forming a combined forecast. We present empirical applications using two‐year sales and individual forecast data provided by a major consumer durables manufacturer to illustrate the feasibility of our proposed procedures.
Hippocampal volumetrics in depression: The importance of the posterior tail
Authors: Maller Jerome J. , Daskalakis Z. Jeff , Fitzgerald Paul B. 
Published: June 2007

AbstractStudies of patients with major depression disorder (MDD) have revealed reduced hippocampal volumes, but findings have been inconsistent due to sample and measurement differences. The current study sought to measure this structure in a large sample of MDD and control subjects, using a strict measurement protocol, in order to elucidate morphological‐specific volumetric differences. Forty‐five subjects with treatment‐resistant MDD and 26 controls underwent psychiatric assessments and brain magnetic resonance imaging (MRI). The findings of this study indicate that (1) MDD results in reduced hippocampal volume, particularly in the tail section, (2) region of interest (ROI) estimation protocols and sample characteristics may help explain volumetric differences between previous MDD studies, and (3) specific ROI atrophy in treatment‐resistant depression is influenced by sex. © 2007 Wiley‐Liss, Inc.
Evidence for a specific role of the anterior hippocampal region in successful associative encoding
Authors: Chua Elizabeth F. , Schacter Daniel L. , Rand‐Giovannetti Erin , Sperling Reisa A. 
Published: June 2007

AbstractIt has been well established that the hippocampal formation plays a critical role in the formation of memories. However, functional specialization within the hippocampus remains controversial. Using functional magnetic resonance imaging (fMRI) during a face‐name associative encoding task, followed by a postscan recognition test for face memory and face‐name pair memory, we investigated the roles of anterior and posterior hippocampal regions in successful encoding of associations and items. Whole‐brain and region of interest (ROI) analyses revealed that the anterior hippocampal formation showed increased activation for subsequently remembered face‐name associations compared with pairs that were forgotten. In contrast, the posterior hippocampal formation showed activation above baseline during attempted encoding of face‐name pairs, but no evidence of differential activation based on subsequent memory. Furthermore, exploratory whole‐brain analyses revealed that a parahippocampal region, most likely corresponding to perirhinal cortex, showed subsequent memory effects for faces. These data provide evidence for functional specialization within the hippocampal formation based on the associative nature of the stimuli and subsequent memory. © 2007 Wiley‐Liss, Inc.
Cisplatin induces mitochondrial oxidative stress with resultant energetic metabolism impairment, membrane rigidification and apoptosis in rat liver
Authors: Martins N. M. , Santos N. A. G. , Curti C. , Bianchi M. L. P. , Santos A. C. 
Published: June 2007

AbstractCisplatin is a potent and widely used chemotherapeutic agent. Nephrotoxicity induced by this drug has been well documented. However, very little information is available on cisplatin‐induced hepatotoxicity and its underlying mechanism remains unclear. High doses of cisplatin have been known to produce hepatotoxicity. Additionally, elevated expression of CYP 2E1 has been associated with enhanced cisplatin‐induced hepatotoxicity. Several studies suggest that cisplatin toxicity occurs by the increased generation of reactive oxygen species (ROS) in mitochondria. Therefore, the present study examined, in vivo, the cisplatin‐induced effects on hepatic mitochondrial structure and function as well as the occurrence of hepatocellular death by apoptosis. Adult male Wistar rats (200–220 g) were divided into two groups (n = 8) treated as follows: (1) control group (saline solution, 1 ml 100 g−1 body weight, i.p.) and (2) cisplatin group (10 mg kg−1 body weight, i.p.). The animals were killed 72 h after the treatment. Hepatotoxicity was evidenced in the cisplatin group by the increased serum levels of alanine (ALT) and aspartate (AST) aminotransferases. The mechanism of cisplatin‐induced hepatotoxicity was found to involve membrane rigidification; decreased GSH/GSSG ratio, ATP, GSH and NADPH levels; lipid peroxidation; oxidative damage of cardiolipin and protein sulfhydryl groups. Moreover, cell death by apoptosis was also demonstrated and the findings strongly suggest the participation of the mitochondrial signaling pathway in this process. Therefore, the results show the key role of mitochondria in the hepatotoxicity induced by cisplatin and delineate several mitochondrial processes that could be targeted in future cytoprotective therapy approaches. Copyright © 2007 John Wiley & Sons, Ltd.
Variation of spectral, structural, and vibrational properties within the intrinsically fluorescent proteins family: A density functional study
Authors: Nifosí Riccardo , Amat Pietro , Tozzini Valentina 
Published: June 2007

AbstractWe report an extensive (time‐dependent) density functional study of the whole series of the chromophores within the Intrinsically Fluorescent Protein family, in the relevant conformations and protonation states. Over 30 structures are considered, including three newly discovered chromophores (zFP, Kaede, and the Orange variant of DsRed). Ab initio calculations on selected structures are also performed in order to assess the performances of TDDFT along the family. The use of a uniform scheme for all structures allows to establish relationships between the absorption energy and electrostatic, structural or vibrational properties of the chromophores. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Pushing the envelope on youth civic engagement: A developmental and liberation psychology perspective
Authors: Watts Roderick J. , Flanagan Constance 
Published: June 2007

AbstractIn this article, we take a critical look at the growing interest in U.S. political participation as it exists in the youth civic engagement literature. Our critique draws from principles of liberation and developmental psychology, and from the incisive writings of experts in youth organizing. Youth Organizing evolved from the Positive Youth Development (PYD) and Community Youth Development (CYD) perspectives but its addition of social justice activism is consistent with liberation psychology. The essence of our critique is this: Although there is certainly value in the current civic engagement literature, much of it focuses on the maintenance of social and political institutions rather than on action for social justice. To promote a better balance, and one more relevant to the lives of youth of color and other marginalized young people, we offer a framework for empirical research on youth sociopolitical development. The focus is on the relationship between social analysis (including critical consciousness) and societal involvement that includes the full range of service and political work. Because youth is the focus, we also include a brief discussion of a distinctive challenge that adults face in doing just work with young people—namely, adultism. © 2007 Wiley Periodicals, Inc. J Comm Psychol 35: 779–792, 2007.
Perturbation of mouse glioma MRS pattern by induced acute hyperglycemia
Authors: Simões R. V. , García‐Martín M. L. , Cerdán S. , Arús C. 
Published: June 2007

Abstract1H MRS is evolving into an invaluable tool for brain tumor classification in humans based on pattern recognition analysis, but there is still room for improvement. Here we propose a new approach: to challenge tumor metabolism in vivo by a defined perturbation, and study the induced changes in MRS pattern. For this we recorded single voxel 1H MR spectra from mice bearing a stereotactically induced GL261 grade IV brain glioma during a period of induced acute hyperglycemia. A total of 29 C57BL/6 mice were used. Single voxel spectra were acquired at 7 T with point resolved spectroscopy and TE of 12, 30 and 136 ms. Tumors were induced by stereotactic injection of 105 GL261cells in 17 mice. Hyperglycemia (up to 338 ± 36 mg/dL glucose in the blood) was induced by intraperitoneal bolus injection. Maximal increases in glucose resonances of up to 2.4‐fold were recorded from tumors in vivo. Our observations are in agreement with extracellular accumulation of glucose, which may suggest that glucose transport and/or metabolism are working close to their maximum capacity in GL261 tumors. The significant and specific MRS pattern changes observed when comparing euglycemia and hyperglycemia may be of use for future pattern‐recognition studies of animal and human brain tumors by enhancing MRS‐based discrimination between tumor types and grades. Copyright © 2007 John Wiley & Sons, Ltd.
The gel swelling properties of alginate fibers and their applications in wound management
Authors: Qin Yimin 
Published: June 2007

AbstractCalcium alginate fibers have a novel gel‐forming capability in that, upon the ion exchange between sodium ions in the contact solution and calcium ions in the fiber, the fiber slowly transforms into a fibrous gel. This paper reviews the principles of the gel‐forming process for alginate fibers and analyzed the gelling behavior of various types of alginate fibers. The absorption characteristics of alginate wound dressings were analyzed and it was found that alginate wound dressings absorb a large quantity of liquid into the fiber structure, in addition to those held between the fibers in the textile structure. This gives rise to the unique gel blocking properties of alginate wound dressings. In addition, alginate wound dressings also have novel hemostatic and antimicrobial properties as well as the ability to promote wound healing. They are now widely used in the management of highly exuding wounds such as leg ulcers, pressure sores, and surgical wounds. Copyright © 2007 John Wiley & Sons, Ltd.
First‐trimester screening for Down syndrome; the role of nasal bone assessment in the Korean population
Authors: Moon Min Hoan , Cho Jeong Yeon , Lee Yu Mi , Jung Sung Il , Yang Jae Hyug , Kim Moon Young , Ryu Hyun‐Mee , Chung Jin Hoon , Park Seong Ho 
Published: June 2007

AbstractObjectives The aim of this study was to evaluate the role of nasal bone assessment in first‐trimester screening for Down syndrome (DS) in the Korean population.Methods From July 2004 to March 2006, we prospectively evaluated the fetal nasal bones at 11–14 weeks' gestation in the Korean population.Results A successful evaluation was possible in 6490 of 6787 fetuses (95.6%). Absent, hypoechoic, and short nasal bones were seen in 4 (26.7%), 4 (26.7%), and 1 (6.7%) of 15 fetuses with DS, respectively, whereas in 5 (0.1%), 11 (0.2%), and 246 (3.8%) of 6456 normal fetuses. The incidence of absent and hypoechoic nasal bone showed significant differences between normal fetuses and fetuses with DS (P < 0.0005, both). Screening for DS using an absent or hypoechoic nasal bone resulted in a sensitivity of 53.3%, a specificity of 99.8%, a positive likelihood ratio of 215.2, and a negative likelihood ratio of 0.5.Conclusion Our study showed that nasal bone abnormality at 11–14 weeks of gestation had a high association with DS in the Korean population. This suggests that nasal bone assessment can be used to supplement the current first‐trimester screening for DS in the Korean population. Copyright © 2007 John Wiley & Sons, Ltd.
Neural tube defects in the sample of genetic counselling
Authors: Joó József Gábor , Beke Artúr , Papp Csaba , Tóth‐Pál Ernő , Csaba Ákos , Szigeti Zsanett , Papp Zoltán 
Published: June 2007

AbstractObjective This study was conducted to evaluate the major demographic details, diagnostical and clinical features, as well as the risk of recurrence of cases with the major types of neural tube defects (NTD). We also examined the efficiency of ultrasonography based on autopsy examinations during 26 years.Methods The investigations were made into the sample of 743 NTD diagnosed between 1 January 1976 and 31 December 2002. A computerized database was used to sum up the available information about the individual cases; in addition to surveying the couples' major demographic details, we also had the opportunity to collect detailed information about the history, diagnostics (ultrasound) and outcome of the pregnancies as well as the results of the autopsies during the investigation.Results In the 743 cases of NTD, maternal and paternal median ages turned out to be 23.7 years (±5.22 years) and 28.7 years (±5.81 years), respectively. The male:female ratio was 0.78. Comparable samples of anencephaly and spina bifida allowed for the conclusion that a positive genetic history was equally often found while a positive obstetrical history was almost twice as common in anencephaly. The sensitivity of the maternal serum‐alpha fetoprotein (AFP) screening test is the highest in anencephaly and lowest in encephalocele. While the majority of cases of anencephaly were diagnosed before the 24th gestational week, examples of diagnosing spina bifida and encephalocele at a later time could also be found. Among the associated malformations other than those of the central nervous system special mentioning should be made of fetal pyelectasia, cleft palate as well as diaphragmatic herniation. No pathological karyotypes were found in association with encephalocele or spina bifida, but anencephaly was accompanied with trisomy 21 and trisomy 18 in one case each. Anencephaly was found to have the highest risk of recurrence in both nervous system malformations and malformations other than those of the nervous system. Sonography proved to be the most reliable method in cases of enecephalocele.Conclusion The respective median values of maternal and paternal age show that aetas has no role in the occurrence of NTDs. NTDs are more common among girls. Positive genetic, obstetrical and medical findings are of great importance in the incidence of NTDs. Although reliable to only a limited extent, maternal serum‐AFP tests are considered to be useful and necessary in screening NTDs, while sonography is the gold standard method in recognizing these frequent malformations. The knowledge of the eventual associated malformations is mainly important in certain cases of spina bifida, which may also yield a good post‐natal prognosis. Our data obtained from the sample of 26 years also confirm that the periconceptional administration of folic acid reduces the incidence and risk of recurrence of NTDs. Copyright © 2007 John Wiley & Sons, Ltd.