bluuebunny/crossref_metadata_2025_split huggingface dataset:
GRAPHICAL SENSITIVITY ANALYSIS WITH DIFFERENT METHODS OF IMPUTATION FOR A TRIAL WITH PROBABLE NON‐IGNORABLE MISSING DATA
Authors: Weatherall M. , Pickering R.M. , Harris Scott 
Published: September 2009

SummaryGraphical sensitivity analyses have recently been recommended for clinical trials with non‐ignorable missing outcome. We demonstrate an adaptation of this methodology for a continuous outcome of a trial of three cognitive‐behavioural therapies for mild depression in primary care, in which one arm had unexpectedly high levels of missing data. Fixed‐value and multiple imputations from a normal distribution (assuming either varying mean and fixed standard deviation, or fixed mean and varying standard deviation) were used to obtain contour plots of the contrast estimates with their P‐values superimposed, their confidence intervals, and the root mean square errors. Imputation was based either on the outcome value alone, or on change from baseline. The plots showed fixed‐value imputation to be more sensitive than imputing from a normal distribution, but the normally distributed imputations were subject to sampling noise. The contours of the sensitivity plots were close to linear in appearance, with the slope approximately equal to the ratio of the proportions of subjects with missing data in each trial arm.
EXPONENTIAL SMOOTHING AND NON‐NEGATIVE DATA
Authors: Akram Muhammad , Hyndman Rob J. , Ord J. Keith 
Published: September 2009

SummaryThe most common forecasting methods in business are based on exponential smoothing, and the most common time series in business are inherently non‐negative. Therefore it is of interest to consider the properties of the potential stochastic models underlying exponential smoothing when applied to non‐negative data. We explore exponential smoothing state space models for non‐negative data under various assumptions about the innovations, or error, process. We first demonstrate that prediction distributions from some commonly used state space models may have an infinite variance beyond a certain forecasting horizon. For multiplicative error models that do not have this flaw, we show that sample paths will converge almost surely to zero even when the error distribution is non‐Gaussian. We propose a new model with similar properties to exponential smoothing, but which does not have these problems, and we develop some distributional properties for our new model. We then explore the implications of our results for inference, and compare the short‐term forecasting performance of the various models using data on the weekly sales of over 300 items of costume jewelry. The main findings of the research are that the Gaussian approximation is adequate for estimation and one‐step‐ahead forecasting. However, as the forecasting horizon increases, the approximate prediction intervals become increasingly problematic. When the model is to be used for simulation purposes, a suitably specified scheme must be employed.
LEVERAGE ADJUSTMENTS FOR DISPERSION MODELLING IN GENERALIZED NONLINEAR MODELS
Authors: Smyth Gordon K. , Verbyla Arūnas P. 
Published: September 2009

SummaryFor normal linear models, it is generally accepted that residual maximum likelihood estimation is appropriate when covariance components require estimation. This paper considers generalized linear models in which both the mean and the dispersion are allowed to depend on unknown parameters and on covariates. For these models there is no closed form equivalent to residual maximum likelihood except in very special cases. Using a modified profile likelihood for the dispersion parameters, an adjusted score vector and adjusted information matrix are found under an asymptotic development that holds as the leverages in the mean model become small. Subsequently, the expectation of the fitted deviances is obtained directly to show that the adjusted score vector is unbiased at least to O(1/n). Exact results are obtained in the single‐sample case. The results reduce to residual maximum likelihood estimation in the normal linear case.
Inequality and Union Membership: The Influence of Relative Earnings and Inequality Attitudes
Authors: Checchi Daniele , Visser Jelle , Van De Werfhorst Herman G. 
Published: October 2009

AbstractUsing surveys from the International Social Survey Programme covering the period 1985–2002 for seven European countries (West and East Germany, Sweden, Norway, Italy, the Netherlands and Great Britain), we examine the effect of relative earnings on union membership and show that union density is higher among workers in the intermediate earnings group than among low or high earners. Next, we examine the association of inequality attitudes with union membership and demonstrate that union membership is not only motivated by instrumental considerations related to relative earnings, but also by normative concerns about inequality. We interpret our findings suggesting that rising earnings inequality is in itself a source of union decline.
Economic Transnationalism and its Ambiguities: The Case of Romanian Migration to Italy
Authors: Ban Cornel 
Published: September 2009

AbstractTaking the case of migratory flows between Romania and Italy as a case study, this article investigates the ways in which spaces of economic transnationalism emerge and are reproduced over time. While the article finds that the role of the state in regulating the flow of money, people and goods across borders remains significant, it nevertheless provides evidence that state authority is systematically challenged by private actors even in the case of migration phenomena with a remarkably short history such as that of Romanians in Italy. Particularly interesting in this respect are labor recruiting networks in which informal headhunter operations, public officials and mobile manufacturing firms interact in surprising ways. While economic forms of transnationalism are the main focus of this investigation, the ways in which transnational capital and labor flows facilitated the symbolic reaffirmation of social institutions in the sending locality are also investigated.
Japanese‐Brazilians and the Future of Brazilian Migration to Japan
Authors: McKenzie David , Salcedo Alejandrina 
Published: September 2009

AbstractThe number of Japanese‐Brazilians working in Japan grew from less than 15,000 in 1989 to more than 300,000 in 2006. This rapid growth in migration was initiated by a law change in Japan allowing third‐generation Japanese‐Brazilians to work in Japan, the “push” of poor economic conditions in Brazil, and the “pull” of a booming economy in Japan. Cultural links between Japan and the Japanese‐Brazilians, together with the development of highly efficient organized labour recruitment networks, have acted to foster this, leading to the creation of what some experts believe to be a self‐sustaining migration system. We use a new representative survey of Japanese‐Brazilians to examine the sustainability of this migration flow. We find both the economic and cultural reasons for emigration to be weakening. Japanese‐Brazilians now occupy the upper tiers of the income and occupational distributions in Brazil, and the majority of the third‐generation are not participating in many aspects of the Japanese community in Brazil. Moreover, demographic analysis shows that over the next 20 years, the share of migration‐age Japanese‐Brazilians who are fourth‐generation will rise considerably, with such individuals not eligible to migrate under current Japanese immigration law. As a consequence, we predict the rapid growth in the Japanese‐Brazilian population in Japan will soon turn to a gradual decline in migrant numbers, and in the long term, erode the stability of this new migration system.
International Migration and Development in Asia: Exploring Knowledge Frameworks
Authors: Asis Maruja M.B. , Piper Nicola , Raghuram Parvati 
Published: September 2009

AbstractThere is revived interest and debate on the relation between international migration and development, with Asia emerging as one important locus for such deliberations. A number of institutions, journals, people and organizations have emerged as key players in these discussions but so far there have been few attempts to investigate the information gathered from the perspective of “knowledge production”. This paper’s objective, therefore, is to outline some of the ways in which knowledge about migration and development is being produced in Asia. We focus on selected aspects of knowledge production to identify the lenses through which much of the work is currently generated and the research imagination resulting from existing approaches.
Attention to novelty in behaviorally inhibited adolescents moderates risk for anxiety
Authors: Reeb‐Sutherland Bethany C. , Vanderwert Ross E. , Degnan Kathryn A. , Marshall Peter J. , Pérez‐Edgar Koraly , Chronis‐Tuscano Andrea , Pine Daniel S. , Fox Nathan A. 
Published: September 2009

Background:  Individual differences in specific components of attention contribute to behavioral reactivity and regulation. Children with the temperament of behavioral inhibition (BI) provide a good context for considering the manner in which certain components of attention shape behavior. Infants and children characterized as behaviorally inhibited manifest signs of heightened orienting to novelty. The current study considers whether this attention profile moderates risk for clinical anxiety disorders among adolescents with a history of BI.Methods:  Participants were assessed at multiple time points for BI, beginning in early childhood. At adolescence, event‐related potentials (ERPs) were recorded during a three‐stimulus auditory novelty oddball task, which employed frequent standard and infrequent deviant tones as well as a set of complex, novel sounds. Clinical diagnosis was carried out using the Schedule for Affective Disorders and Schizophrenia for School‐Age Children‐Present and Lifetime Version (K‐SADS‐PL). P3 and mismatch negativity (MMN) components were examined at midline frontal, central, and parietal electrode sites.Results:  Individuals who displayed high levels of BI during childhood and increased P3 amplitude to novelty in adolescence were more likely to have a history of anxiety disorders compared to behaviorally inhibited adolescents with lower P3 amplitudes. Groups did not differ on measures of MMN.Conclusions:  Increased neural responses to novelty moderate risk for anxiety disorders amongst individuals with a history of BI.
Determining soil organic carbon for agricultural soils: a comparison between the Walkley & Black and the dry combustion methods (north Belgium)
Authors: Meersmans J. , Van Wesemael B. , Van Molle M. 
Published: September 2009

AbstractMapping soil organic carbon (SOC) and establishing any change over time are important because of CO2 fluxes between soil and atmosphere and cropland decreases in SOC. The latter is one of the main causes of soil fertility decline and increased erodibility. As most analytical methods underestimate total SOC content, correction factors are needed to avoid methodological bias when comparing SOC data from sampling campaigns using different analytical procedures. The traditional method for SOC analysis used to be, and in most cases still is wet oxidation in potassium dichromate, better known as the Walkley & Black method. In this study, we aim to estimate correction factors for the classic and modified version of the Walkley & Black method for different land use and soil type combinations for agricultural soils in north Belgium. General correction factors of 1.47 for the classic Walkley & Black method and 1.20 for the modified Walkley & Black method are proposed. The results show that sandy grassland soils are characterised by lower recoveries than silt loam grassland soils. Furthermore, the correction factor appears to increase with soil wetness.
Collective action in water‐point management: The case of pastoral and agropastoral communities in eastern Ethiopia
Authors: Beyene Fekadu 
Published: September 2009

AbstractThis paper explores collective activities in water‐point management by pastoral and agropastoral herders. It examines conditions that strengthen or weaken cooperative behaviour. By employing a comparative case study approach, the paper covers three types of water‐points: ponds, cisterns and water wells. Results show that factors beyond the expectation of economic benefits influence the development of cooperative behaviour, including embedded social relationships, which provide a basis for sanctions. However, the absence of clear allocation rules and of secure property rights discourages sustained contribution of inputs. The study also finds that the contribution, and the ultimate benefits gained, by the members of the group are dependent on limited technological options and other attributes of the water‐points they manage. Interestingly, divergence of interests (between economic elites and poor herders) in institutional change precluding the establishment of cisterns negatively affects the livelihoods of the poor (agro) pastoralists. Where internal capacity is limited, assisted collective action that builds on diverse local interests could contribute to sustainable management of collectively used water‐points. The study concludes that both economic incentives and socio‐cultural norms affect collective action in a more complex way than the theory of determinants of collective action predicts.
What drives large South African corporations to invest in sub‐Saharan Africa? CEO's perspectives and implications for FDI policies
Authors: Dippenaar Adriaan 
Published: September 2009

AbstractForeign direct investment (FDI) flowing into Africa is highly diverse in terms of the origin of the investors, size of the firms, and the sectors of activity. The motivations and factors driving firms' decisions to invest in Africa are equally diverse. A direct survey of senior management in South African firms that are operating in sub‐Saharan Africa reveals that the drivers of foreign investment as well as the risks and the strategies to overcome them differ markedly between sectors. A further finding is that there is a limited pool of FDI promotion policies and incentives that governments can institute that are effective in impacting South African corporations' investment decisions. As a consequence, broad‐based FDI promotion policies aimed at attracting FDI across all investor groups are likely to have limited impact in attracting FDI from any particular investor group, or in attracting any FDI from multinational companies similar to the South African companies studied here. Such broad based policies probably need to be complemented with policies targeting those specific firms or sectors which countries hope to attract.
Handling uncertainty: Policy and organizational practices in Tanzania's small‐scale gold mining sector
Authors: Jønsson Jesper Bosse , Fold Niels 
Published: September 2009

AbstractSmall‐scale mining supports the livelihoods of several hundred thousand rural households in Africa. Nonetheless, the understanding of the organizational dynamics of small‐scale miners' activities is modest. The paper outlines the small‐scale mining codes in Tanzania and contrasts them to prevalent organizational practices in two Tanzanian small‐scale mining settlements. It is argued that there is a need to adjust the regulatory mechanisms to well‐consolidated practices: If basic practices differ substantially from official prescriptions of the mining codes over an extended period of time, certain elements of the regulatory framework need reconsideration. The paper examines three pertinent operational components that vary in form and managing practices between the two study sites: dealing with licence acquisition, accessing working capital, and sharing output. These components are considered vital for the proper manoeuvring of local small‐scale mining operators and the reasons for the variations are essential to understand for policymakers and development practitioners. By incorporating prevalent practices and context‐dependent variations in some of the crucial organizational components, it is possible to design a robust and resilient regulatory framework for small‐scale mining. A number of policy adjustments are consequently proposed.
Labour challenges and mercury management at gold mills in Zimbabwe: Examining production processes and proposals for change
Authors: Spiegel Samuel J. 
Published: September 2009

AbstractThe use of mercury in small‐scale gold mining has been a growing concern in many parts of Africa. However, although the negative effects of mercury pollution are increasingly reported, little has been written about how labour relationships and gold production challenges in mining communities affect mercury management practices. This article provides an integrative analysis of small‐scale gold extraction processes, labour challenges, and mercury use at gold mills in Zimbabwe, focusing on a gold rush area in Mashonaland West Province. It examines practices employed by miners who have limited economic capacities to upgrade technologies, and how the complex relationships between miners, mill owners and government regulators affect environmental performance. The study draws attention to how poor environmental management practices relate to labour inequities, low gold recovery as well as the informal gold trade dynamics amid the country's economic crisis. Results of a United Nations‐supported stakeholder consultation process are discussed, with proposals for improving labour conditions and reducing environmental risk. The article highlights why the government should develop and support local programs to assist miners, as well as the decisive roles mill owners could take in ensuring improved standards on their sites.
Variation in Almotriptan Effectiveness According to Different Prophylactic Treatments
Authors: Bermejo Pedro Emilio , Dorado Rodolfo , Gomez‐Arguelles Jose Maria 
Published: September 2009

Objective.— To evaluate the effect of different migraine prophylaxis medications on subject responsiveness to almotriptan.Background.— There is evidence supporting an increase of responsiveness of symptomatic medications for migraine attacks by some prophylactic treatments although this has not been probed.Methods.— A total of 345 patients (230 women, mean age 37.3) with episodic or chronic migraine were classified according to the prophylaxis they were taking in the following groups: (1) no prophylactic medication; (2) propranolol; (3) topiramate; (4) flunarizine. Decrease in Analogical Visual Scale and pain‐free at 2 hours after almotriptan intake was assessed at 2 months. Side effects and discontinuation or treatment were also assessed.Results.— Headache severity was reduced 4.2 in control group, 5.3 in propranolol group, 4.1 in topiramate group, and 4.0 in flunarizine group, whereas pain‐free status was achieved in 37.3%, 48.7%, 36.1%, and 38.1% respectively. These two parameters were statistically significative between propranolol and control groups. Side effects were similar in all groups.Conclusions.— Our results displayed a higher efficacy of almotriptan in propranolol group and we hypothesized it may be due to a common mechanism of action at serotoninergic receptors.
PTSD, Combat Injury, and Headache in Veterans Returning From Iraq/Afghanistan
Authors: Afari Niloofar , Harder Laura H. , Madra Naju J. , Heppner Pia S. , Moeller‐Bertram Tobias , King Clay , Baker Dewleen G. 
Published: September 2009

Objective.— To examine the relationship between posttraumatic stress disorder, combat injury, and headache in Operation Iraqi Freedom and Operation Enduring Freedom veterans at the VA San Diego Healthcare System.Background.— Previous investigations suggest that a relationship between posttraumatic stress disorder and primary headache disorders exists and could be complicated by the contribution of physical injury, especially one that results in loss of consciousness. These associations have not been systematically examined in Operation Iraqi Freedom and Operation Enduring Freedom veterans.Methods.— In this observational cross‐sectional study, a battery of self‐report, standardized questionnaires was completed by 308 newly registered veterans between March and October 2006. The Davidson Trauma Scale was used to determine the degree of posttraumatic stress disorder symptoms and combat‐related physical injury was assessed by self‐report. The presence of headache was based on a symptom checklist measure and self‐reported doctor diagnoses. Logistic regression analysis was performed to predict presence of headache and determine odds ratios and 95% confidence intervals associated with demographic, military, in‐theatre, and mental health characteristics.Results.— About 40% of the veterans met the criteria for posttraumatic stress disorder; 40% self‐reported current headache, 10% reported a physician diagnosis of migraine, 12% a physician diagnosis of tension‐type headache, and 6% reported both types of headache. Results from the logistic regression model indicated that combat‐related physical injury (odds ratio: 2.25; 95% confidence interval: 1.17‐4.33) and posttraumatic stress disorder (odds ratio: 4.13; 95% confidence interval: 2.44‐6.99) were independent predictors of self‐reported headache. Additional analyses found that veterans with both tension and migraine headache had higher rates of posttraumatic stress disorder (chi‐square [d.f. = 3] = 15.89; P = .001) whereas veterans with migraine headache alone had higher rates of combat‐related physical injury (chi‐square [d.f. = 9] = 22.00; P = .009).Conclusion.— Posttraumatic stress disorder and combat‐related physical injury were related to higher rates of self‐reported headache in newly returning veterans. Our finding that posttraumatic stress disorder and injury during combat are differentially related to migraine and tension‐type headache, point to a complex relationship between physical and psychological trauma and headache. These findings have implications for a comprehensive approach to interventions for headache and the physical and psychological sequelae of trauma.
GENETIC POPULATION STRUCTURE OF PSEUDO‐NITZSCHIA PUNGENS (BACILLARIOPHYCEAE) FROM THE PACIFIC NORTHWEST AND THE NORTH SEA1
Authors: Adams Nicolaus G. , Trainer Vera L. , Rocap Gabrielle , Herwig Russell P. , Hauser Lorenz 
Published: September 2009

Several species of the diatom Pseudo‐nitzschia produce the neurotoxin domoic acid (DA). Consumption of fish and shellfish that have accumulated this potent excitotoxin has resulted in severe illness and even death in humans, marine mammals, and seabirds. Pseudo‐nitzschia pungens (Grunow ex Cleve) Hasle is a cosmopolitan diatom commonly occurring in the waters of the Pacific Northwest (PNW) and the eastern North Atlantic, including the North Sea. However, genetic and physiological relationships among populations throughout this large geographic distribution have not been assessed. Population genetic parameters (e.g., Hardy–Weinberg equilibrium, linkage equilibrium, FST) calculated for P. pungens collected from the Juan de Fuca eddy region in the PNW indicated the presence of two distinct groups that were more divergent from each other than either was from a P. pungens sample from the North Sea. Geographic heterogeneity was also detected within each of the two PNW groups. These results suggested that the populations of P. pungens recently mixed in the Juan de Fuca eddy region (a seasonally retentive feature off the coasts of Washington State, USA, and Vancouver Island, Canada) but did not exchange genetic material by sexual reproduction. Alternatively, these two groups may be cryptic (morphologically identical, but reproductively isolated) species. Identifying cryptic diversity in Pseudo‐nitzschia is important for bloom prediction and aiding the identification of molecular markers that can be used for rapid detection assay development.