bluuebunny/crossref_metadata_2025 huggingface dataset:
An Analysis of Workplace Representatives, Union Power and Democracy in Australia
Authors: Peetz David , Pocock Barbara
Published: May 2009

The purpose of this article is to illuminate the views and experiences of workplace representatives in Australia in the context of falling union density, and to analyse factors that are most strongly associated with subjective union power at the workplace level, as perceived by delegates. The analysis relies on a large random survey of workplace delegates in eight significant Australian unions. The article describes the situation broadly facing delegates as shown by the survey and analyses a set of factors associated with the power of workers as perceived by delegates. We find that higher levels of reported activism among delegates are strongly associated with greater subjective union power. We also find that self‐reported delegate confidence is also strongly associated with perceptions of higher union power, as is delegate's clarity about their roles. The data also show a strong association between perceptions of democracy within the union and union power. Support for delegates from the union office and organizers is also associated with higher levels of union power at the local level. The analysis provides some support for union renewal strategies associated with the ‘organizing model’ as applied in Australia and some other Anglo‐Saxon countries that aim to increase the activism of workplace delegates through education, the provision of support for workplace delegates and more democratic union structures.
Worker Control as a Facilitator in the Match between Education and Jobs
Authors: Weststar Johanna
Published: May 2009

This article examines the relationship between worker control and subjective underemployment among workers who have more education than is needed for entry into their jobs (credential underemployment). Results indicate that social and technical controls are related to a greater sense of education–job matching. Workers who have credential underemployment are less likely to report subjective underemployment (underutilization and lack of fit between education and job) if they have higher levels of workplace control. This article contains implications for job design and the role of employers and managers in fostering the utilization of their workforces.
Legality Policies and Theories of Legality: From Bananas to Radbruch's Formula*
Authors: SARTOR GIOVANNI
Published: May 2009

Abstract.  In this paper I shall take an inferential approach to legality (legal validity), and consider how the legality of a norm can be inferred, and what can be inferred from it. In particular, I shall analyse legality policies, namely, conditionals conferring the quality of legality upon norms having certain properties, and I shall examine to what extent such conditionals need to be positivistic, so that legality is only dependant on social facts. Finally, I shall consider how legality is transmitted from norm to norm and whether the ultimate legality policies (the rules of recognition) of a legal system need to be constituted by social facts.
Between Law and Social Norms: The Evolution of Global Governance
Authors: CALLIESS GRALF‐PETER , RENNER MORITZ
Published: May 2009

Abstract. It is commonplace that economic globalization poses new challenges to legal theory. But instead of responding to these challenges, legal scholars often get caught up in heated yet purely abstract discussions of positivist and legal pluralist conceptions of the law. Meanwhile, economics‐based theories such as “Law and Social Norms” have much less difficulty in analysing the newly arising forms of private and hybrid “governance without government” from a functional perspective. While legal theory has much to learn from these approaches, we argue that they fail in one crucial point: They cannot uphold the analytical distinction between law and non‐law. The reasons for this shortcoming are theory‐immanent in that the economic theories' focus on efficiency and their actor‐based perspective are necessarily blind to “law's own rationality.” We therefore propose to further develop those functional approaches to the study of global governance by complementing them with elements from Niklas Luhmann's systems theory of law. This will provide us with a conceptual framework for analyzing the workings of global governance regimes without ignoring their potential for “legalisation” and “constitutionalisation.” As we will show in three concrete examples (Corporate Social Responsibility,lex mercatoria, and internet regulation) we can thus describe the evolution of new forms of legal regulation beyond the nation‐state. This will also allow us to draw some preliminary conclusions on the role of law in the context of globalization and, at the same time, show the direction for further empirical research.
Killing the Golden Goose? Third Sector Organizations and Back‐to‐Work Programmes in Germany and the UK
Authors: Aiken Mike , Bode Ingo
Published: May 2009

Third sector, or not‐for‐profit, organizations have been viewed in many parts of Europe as agencies that can be harnessed by public policy programmes to support the socially excluded. Within the emerging mixed economy of welfare, third sector agencies offering training, support and employment for groups disadvantaged in the labour market provide an important example. This illustrates, from one specific field, the dynamics occurring at the interface between public and third sectors in the delivery of public policy goals. This article examines both the history of ‘partnership regimes’ in this field and the evolving local organizational arrangement. The developments in the contrasting welfare regimes of Britain and Germany, which exemplify different institutional traditions, are analysed. The potential impact of regulatory changes on the capacity of third sector work integration agencies to deliver policy goals is assessed in both countries using evidence from recent case study research. The analysis suggests that the emerging managerialist partnership structures are tending to convert third sector organizations into ‘just in time’ deliverers of poor programme outcomes in both welfare regimes while also eroding their distinctive potential to provide more than mere labour market integration.
Determining Semi‐Normative Poverty Lines Using Social Survey Data
Authors: Deeming Christopher
Published: May 2009

Debates about how to set minimum income standards for health and general well‐being are very current in Britain. Family budget standards remain popular but the results can be criticized for being little more than abstractions. They are to an extent ‘artificial’ and this raises questions about their ‘real adequacy’. Another way to operationalize adequacy of income, in a lived sense, is to consider the household income levels at which a specified, desirable, healthy standard of living is in fact achieved, indicated here by diet and nutrition. Data are taken from the United Kingdom's Expenditure and Food Survey; the sample has been restricted to an older population, and three years of data (2002–5) provided a combined sample of 4,300 households. The study findings and semi‐normative poverty lines are critically discussed in relation to the national UK policy context as well as the international research literature on poverty measurement.
An Alternative to Remnant Movement for Partial Predicate Fronting
Authors: Vicente Luis
Published: May 2009

Abstract. One of the main tenets of transformational grammar is that movement processes affect heads and phrases in different ways. In this article, I argue against this claim and propose that heads should be allowed to move in the same way as phrases. Conceptually, this proposal is the logical consequence of a common set of assumptions about syntax in general and movement in particular. Empirically, it finds support in the Spanish predicate cleft construction.
Probabilistic neural networks combined with wavelet coefficients for analysis of electroencephalogram signals
Authors: Übeyli Elif Derya
Published: May 2009

Abstract: In this paper, the probabilistic neural network is presented for classification of electroencephalogram (EEG) signals. Decision making is performed in two stages: feature extraction by wavelet transform and classification using the classifiers trained on the extracted features. The purpose is to determine an optimum classification scheme for this problem and also to infer clues about the extracted features. The present research demonstrates that the wavelet coefficients obtained by the wavelet transform are features which represent the EEG signals well. The conclusions indicate that the probabilistic neural network trained on the wavelet coefficients achieves high classification accuracies (the total classification accuracy is 97.63%).
Qualitative analysis of goat and sheep production data using self‐organizing maps
Authors: Magdalena R. , Fernández C. , Martín J. D. , Soria E. , Martínez M. , Navarro M. J. , Mata C.
Published: May 2009

Abstract: The aim of this study was to analyse the relationship between different small ruminant livestock production systems with different levels of specialization. The analysis is carried out by using the self‐organizing map. This tool allows high‐dimensional input spaces to be mapped into much lower‐dimensional spaces, thus making it much more straightforward to understand any set of data. These representations enable the visual extraction of qualitative relationships among variables (visual data mining), converting the data to maps. The data used in this study were obtained from surveys completed by farmers who are principally dedicated to goat and sheep production. With the self‐organizing map we found a relationship between qualitative and quantitative variables showing that more specialized farms have greater milk incomes per goat, highlighting farms that have a greater number of animals, better facilities (including milking machines) or animals fed with elaborated diets. The use of self‐organizing maps for the analysis of this kind of data has proven to be highly valuable in extracting qualitative conclusions and in guiding improvements in farm performance.
An automated hierarchical gait pattern identification tool employing cross‐correlation‐based feature extraction and recurrent neural network based classification
Authors: Dutta Saibal , Chatterjee Amitava , Munshi Sugata
Published: May 2009

Abstract: In this paper Elman's recurrent neural network (ERNN) is employed for automatic identification of healthy and pathological gait and subsequent diagnosis of the neurological disorder in pathological gaits from the respective gait patterns. Stance, swing and double support intervals (expressed as percentages of stride) of 63 subjects were analysed for a period of approximately 300 s. The relevant gait features are extracted from cross‐correlograms of these signals with corresponding signals of a reference subject. These gait features are used to train modular ERNNs performing binary and tertiary classifications. The average accuracy of binary classifiers is obtained as 90.6%–97.8% and that of tertiary classifiers is 89.8%. Hence, two hierarchical schemes are developed each of which uses more than one modular ERNN to segregate healthy, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis subjects. The average testing performances of the schemes are 83.8% and 87.1%.
Axiom‐based ontology matching
Authors: Fürst Frédéric , Trichet Francky
Published: May 2009

Abstract: Managing multiple ontologies is now a core question in most of the applications that require semantic interoperability. The semantic web is surely the most significant application of this report: the current challenge is not to design, develop and deploy domain ontologies but to define semantic correspondences among multiple ontologies covering overlapping domains. In this paper, we introduce a new approach of ontology matching named axiom‐based ontology matching. As this approach is founded on the use of axioms, it is mainly dedicated to heavyweight ontologies, but it can also be applied to lightweight ontologies as a complementary approach to the current techniques based on the analysis of natural language expressions, instances and/or taxonomical structures of ontologies. This new matching paradigm is defined in the context of the conceptual graphs model, where the projection (i.e. the main operator for reasoning with conceptual graphs which corresponds to homomorphism of graphs) is used as a means to semantically match the concepts and the relations of two ontologies through the explicit representation of the axioms in terms of conceptual graphs. We also introduce an ontology of representation, called MetaOCGL, dedicated to the reasoning of heavyweight ontologies at the meta‐level.
LEKTI‐1 in sickness and in health
Authors: Roelandt T. , Thys B. , Heughebaert C. , De Vroede A. , De Paepe K. , Roseeuw D. , Rombaut B. , Hachem J.‐P.
Published: May 2009

Synopsis

The stratum corneum (SC) is a biosensor that mediates responses to a variety of exogenous insults through various signalling mechanisms, including the activation of SC serine proteases (SP) kallikrein cascade. The SPINK5 gene encodes an SP inhibitor, the lympho‐epithelial‐Kazal‐type‐1 inhibitor (LEKTI‐1), which in turn will buffer the excess of SP cascade initiation, key in the maintenance of permeability barrier homeostasis. We demonstrate that LEKTI processing can occur within the SC after secretion from stratum granulosum keratinocytes at least partially by klk7, an SC‐specific chymotryptic SP. Unlike the recently described LEKTI‐2, neither recombinant full‐length LEKTI‐1 nor recombinant LEKTI‐1 fragments exhibit antimicrobial activity. Finally, we discuss the pathophysiological implications of LEKTI‐1 in skin biology as well as its contribution to the pathogenesis of Netherton Syndrome and its potential involvement in atopic dermatitis.
Impact of transition zones, variable fluid viscosity and anthropogenic activities on coupled fluid‐transport processes in a shallow salt‐dome environment
Authors: MAGRI F. , BAYER U. , MAIWALD U. , OTTO R. , THOMSEN C.
Published: May 2009

In the Schleswig–Holstein region (S–H) of Germany, most observed near‐surface saline ground waters originate from dissolution of shallow salt domes. Previous numerical simulations of thermohaline flow clarified the major mechanisms controlling large‐scale density‐driven flow. It has been found that, in addition to topographically driven flow, gravitational and thermohaline convection are the primary mechanisms for extensive solute exchange between shallow and deep aquifers. Geological features such as glacial channels control recharge/discharge processes at the surface. Here we address several previously unresolved issues: (i) the impact of a permeable unit (transition zone) between the salt and adjacent units; (ii) the role of variable brine viscosity in affecting regional‐ (i.e. km‐) scale heat and mass patterns; and (iii) the influence of anthropogenic activities such as pumping stations on density‐driven flow. We found that geophysical factors play a major role in determining the dynamics of fluid processes. The transition zone significantly influences the flow field and the distribution of heat, slowing the formation of highly concentrated salty plumes. The impact of variable fluid viscosity on the coupled heat and brine flow is twofold. In a colder and highly concentrated environment, such as a shallow salt‐dome crest, it retards brine flow. In a less saline environment, variable fluid viscosity enhances thermally induced upward fluid flow. Groundwater extraction from production wells only affects brine and heat flow locally within the upper aquifers.
Executive function deficits in children with fetal alcohol spectrum disorders (FASD) measured using the Cambridge Neuropsychological Tests Automated Battery (CANTAB)
Authors: Green C.R. , Mihic A.M. , Nikkel S.M. , Stade B.C. , Rasmussen C. , Munoz D.P. , Reynolds J.N.
Published: May 2009

Background:  Chronic prenatal alcohol exposure causes a spectrum of deleterious effects in offspring, collectively termed fetal alcohol spectrum disorders (FASD), and deficits in executive function are prevalent in FASD. The goal of this research was to test the hypothesis that children with FASD exhibit performance deficits in tasks that assess attention, planning and spatial working memory.

Methods:  Subjects (8–15 years male and female children) with a diagnosis of fetal alcohol syndrome (FAS), partial FAS (pFAS), or alcohol‐related neurodevelopmental disorder (ARND), and age‐ and sex‐matched controls, completed four tasks selected from the Cambridge Neuropsychological Tests Automated Battery (CANTAB®).

Results:  Compared with age‐matched control children (n = 92), subjects with FASD (n = 89) exhibited longer reaction and decision times (effect size range; Cohen's d = .51 to .73), suggesting deficits in attention. Children with FASD demonstrated deficits in planning and spatial working memory that became more pronounced when task difficulty increased. The largest effect size in this study population (Cohen’s d = 1.1) occurred in the spatial working memory task. Only one outcome measure revealed differences across the diagnostic subgroups, although all groups were different from control.

Conclusion:  This study demonstrates that deficits in multiple executive function domains, including set shifting, planning and strategy use, attention and spatial working memory, can be assessed in children with FASD using an easy to administer, brief battery of computer‐based neuropsychological tasks. The tasks appear to be equally sensitive for brain injury resulting from prenatal exposure to alcohol, regardless of the presence of facial dysmorphology.
The foraging decisions of a central place foraging seabird in response to fluctuations in local prey conditions
Authors: Burke C. M. , Montevecchi W. A.
Published: May 2009

During reproduction, seabirds need to balance the demands of self‐ and offspring‐provisioning within the constraints imposed by central place foraging. To assess behavioral adjustments and tolerances to these constraints, we studied the feeding tactics and reproductive success of common murres (also known as common guillemots) Uria aalge, at their largest and most offshore colony (Funk Island) where parents travel long distances to deliver a single capelin Mallotus villosus to their chicks. We assessed changes in the distance murres traveled from the colony, their proximate foraging locations and prey size choice during two successive years in which capelin exhibited an order of magnitude decrease in density and a shift from aggregated (2004) to dispersed (2005) distributions. When capelin availability was low (2005), parental murres increased their maximum foraging distances by 35% (60 to 81 km) and delivered significantly larger capelin to chicks, as predicted by central place foraging theory. Murres preferred large (>140 mm) relative to small capelin (100–140 mm) in both years, but unexpectedly this preference increased as the relative density of large capelin decreased. We conclude that single prey‐loading murres target larger capelin during long foraging trips as parents are ‘forced’ to select the best prey for their offspring. Low fledgling masses suggest also that increased foraging time when capelin is scarce may come at a cost to the chicks (i.e. fewer meals per day). Murres at this colony may be functioning near physiological limits above which further or sustained adjustments in foraging effort could compromise the life‐time reproductive success of this long‐lived seabird.
Cell‐derived microparticles: a new challenge in neuroscience
Authors: Doeuvre Loïc , Plawinski Laurent , Toti Florence , Anglés‐Cano Eduardo
Published: May 2009

Microparticles (MPs) are membrane fragments shed by cells activated by a variety of stimuli including serine proteases, inflammatory cytokines, growth factors, and stress inducers. MPs originating from platelets, leukocytes, endothelial cells, and erythrocytes are found in circulating blood at relative concentrations determined by the pathophysiological context. The procoagulant activity of MPs is their most characterized property as a determinant of thrombosis in various vascular and systemic diseases including myocardial infarction and diabetes. An increase in circulating MPs has also been associated with ischemic cerebrovascular accidents, transient ischemic attacks, multiple sclerosis, and cerebral malaria. Recent data indicate that besides their procoagulant components and identity antigens, MPs bear a number of bioactive effectors that can be disseminated, exchanged, and transferred via MPs cell interactions. Furthermore, as activated parenchymal cells may also shed MPs carrying identity antigens and biomolecules, MPs are now emerging as new messengers/biomarkers from a specific tissue undergoing activation or damage. Thus, detection of MPs of neurovascular origin in biological fluids such as CSF or tears, and even in circulating blood in case of blood–brain barrier leakage, would not only improve our comprehension of neurovascular pathophysiology, but may also constitute a powerful tool as a biomarker in disease prediction, diagnosis, prognosis, and follow‐up.
Logging Concessions Can Extend the Conservation Estate for Central African Tropical Forests
Authors: CLARK C.J. , POULSEN J.R. , MALONGA R. , ELKAN, Jr. P.W.
Published: May 2009

Abstract: The management of tropical forest in timber concessions has been proposed as a solution to prevent further biodiversity loss. The effectiveness of this strategy will likely depend on species‐specific, population‐level responses to logging. We conducted a survey (749 line transects over 3450 km) in logging concessions (1.2 million ha) in the northern Republic of Congo to examine the impact of logging on large mammal populations, including endangered species such as the elephant (Loxodonta africana), gorilla (Gorilla gorilla), chimpanzee (Pan troglodytes), and bongo (Tragelaphus eurycerus). When we estimated species abundance without consideration of transect characteristics, species abundances in logged and unlogged forests were not different for most species. When we modeled the data with a hurdle model approach, however, analyzing species presence and conditional abundance separately with generalized additive models and then combining them to calculate the mean species abundance, species abundance varied strongly depending on transect characteristics. The mean species abundance was often related to the distance to unlogged forest, which suggests that intact forest serves as source habitat for several species. The mean species abundance responded nonlinearly to logging history, changing over 30 years as the forest recovered from logging. Finally the distance away from roads, natural forest clearings, and villages also determined the abundance of mammals. Our results suggest that logged forest can extend the conservation estate for many of Central Africa's most threatened species if managed appropriately. In addition to limiting hunting, logging concessions must be large, contain patches of unlogged forest, and include forest with different logging histories.
Do Mergers Improve Information? Evidence from the Loan Market
Authors: PANETTA FABIO , SCHIVARDI FABIANO , SHUM MATTHEW
Published: May 2009

We examine the informational effects of M&As by investigating whether bank mergers improve banks' ability to screen borrowers. By exploiting a data set in which we observe a measure of a borrower's default risk that the lenders observe only imperfectly, we find evidence of these informational improvements. Mergers lead to a closer correspondence between interest rates and individual default risk: after a merger, risky borrowers experience an increase in the interest rate, while nonrisky borrowers enjoy lower interest rates. These informational benefits appear to derive from improvements in information processing resulting from the merger, rather than from explicit information sharing on individual customers among the merging parties. Our evidence suggests that part of these informational improvements stem from the consolidated banks using “hard” information more intensively.
Determinants of Bank‐Market Structure: Efficiency and Political Economy Variables
Authors: GONZÁLEZ FRANCISGO
Published: May 2009

This paper analyzes how bank efficiency and political economy variables influence bank‐market structure in 69 countries. Results for more than 2,500 banks over the 1996–2002 period indicate that the ability of the efficiency‐structure hypothesis to explain bank‐market structure varies across countries, depending on national political economy variables. Increased market monitoring and a better‐quality contracting environment amplify the positive influence of bank efficiency on market share and market concentration. Stricter bank entry requirements and more generous deposit insurance schemes, however, mitigate the influence of bank efficiency on market share and market concentration.
Inflation Persistence, Monetary Policy, and the Great Moderation
Authors: CARLSTROM CHARLES T. , FUERST TIMOTHY S. , PAUSTIAN MATTHIAS
Published: May 2009

There is growing evidence that the empirical Phillips curve within the United States has changed significantly since the early 1980s. In particular, inflation persistence has declined sharply. This paper demonstrates that this decline is consistent with a standard dynamic New Keynesian (DNK) model in which: (i) the variability of technology shocks has declined and (ii) the central bank more aggressively responds to inflation.
Regulation and the Neo‐Wicksellian Approach to Monetary Policy
Authors: DUCA JOHN V. , WU TAO
Published: May 2009

Laubach and Williams (2003) employ a Kalman filter approach to jointly estimate the neutral real federal funds rate and trend output growth using an IS relationship and an output‐gap‐based inflation equation. They find a positive link between these two variables, but also much error surrounding neutral real rate estimates. We modify their approach by including variables for regulations on deposit interest rates and on wages and prices. These variables are statistically significant and notably affect estimates of two policy‐relevant coefficients: the sensitivity of output to the real interest rate and that of inflation to the output gap.
Level Playing Fields in International Financial Regulation
Authors: MORRISON ALAN D. , WHITE LUCY
Published: May 2009

We analyze the desirability of level playing fields in international financial regulation. In general, level playing fields impose the standards of the weakest regulator upon the best‐regulated economies. However, they may be desirable when capital is mobile because they counter a cherry‐picking effect that lowers the size and efficiency of banks in weaker economies. Hence, while a laissez faire policy favors the better‐regulated economy, level playing fields are good for weaker regulators. We show that multinational banking mitigates the cherry‐picking effect, and reduces the damage that a level playing field causes in the better‐regulated economy.
Bank Loan Supply, Lender Choice, and Corporate Capital Structure
Authors: LEARY MARK T.
Published: May 2009

This paper explores the relevance of capital market supply frictions for corporate capital structure decisions. To identify this relationship, I study the effect on firms' financial structures of two changes in bank funding constraints: the 1961 emergence of the market for certificates of deposit, and the 1966 Credit Crunch. Following an expansion (contraction) in the availability of bank loans, leverage ratios of bank‐dependent firms significantly increase (decrease) relative to firms with bond market access. Concurrent changes in the composition of financing sources lend further support to the role of credit supply and debt market segmentation in capital structure choice.
International Taxation and the Direction and Volume of Cross‐Border M&As
Authors: HUIZINGA HARRY P. , VOGET JOHANNES
Published: May 2009

We show that the parent‐subsidiary structure of multinational firms created by cross‐border mergers and acquisitions is affected by the prospect of international double taxation. Specifically, the likelihood of parent firm location in a country following a cross‐border takeover is reduced by high international double taxation of foreign‐source income. At the same time, countries with high international double taxation attract smaller numbers of parent firms. A unilateral elimination of worldwide taxation by the United States is simulated to increase the proportion of parent firms locating in the United States following cross‐border mergers and acquisitions from 53% to 58%.
Trading Costs and Returns for U.S. Equities: Estimating Effective Costs from Daily Data
Authors: HASBROUCK JOEL
Published: May 2009

The effective cost of trading is usually estimated from transaction‐level data. This study proposes a Gibbs estimate that is based on daily closing prices. In a validation sample, the daily Gibbs estimate achieves a correlation of 0.965 with the transaction‐level estimate. When the Gibbs estimates are incorporated into asset pricing specifications over a long historical sample (1926 to 2006), the results suggest that effective cost (as a characteristic) is positively related to stock returns. The relation is strongest in January, but it appears to be distinct from size effects.
Rank‐Order Tournaments and Incentive Alignment: The Effect on Firm Performance
Authors: KALE JAYANT R. , REIS EBRU , VENKATESWARAN ANAND
Published: May 2009

We investigate simultaneously the impact of promotion‐based tournament incentives for VPs and equity‐based (alignment) incentives for VPs and the chief executive officer (CEO) on firm performance. We find that tournament incentives, as measured by the pay differential between the CEO and VPs, relate positively to firm performance. The relation is more positive when the CEO nears retirement and less positive when the firm has a new CEO, and weakens further when the new CEO is an outsider. Our analysis is robust to corrections for endogeneity of all our incentive measures and to several alternative measures of tournament incentives and firm performance.
A Parametric ROC Model‐Based Approach for Evaluating the Predictiveness of Continuous Markers in Case–Control Studies
Authors: Huang Y. , Pepe M. S.
Published: May 2009

SummaryThe predictiveness curve shows the population distribution of risk endowed by a marker or risk prediction model. It provides a means for assessing the model's capacity for stratifying the population according to risk. Methods for making inference about the predictiveness curve have been developed using cross‐sectional or cohort data. Here we consider inference based on case–control studies, which are far more common in practice. We investigate the relationship between the ROC curve and the predictiveness curve. Insights about their relationship provide alternative ROC interpretations for the predictiveness curve and for a previously proposed summary index of it. Next the relationship motivates ROC based methods for estimating the predictiveness curve. An important advantage of these methods over previously proposed methods is that they are rank invariant. In addition they provide a way of combining information across populations that have similar ROC curves but varying prevalence of the outcome. We apply the methods to prostate‐specific antigen (PSA), a marker for predicting risk of prostate cancer.
A Model‐Based Approach for Making Ecological Inference from Distance Sampling Data
Authors: Johnson Devin S. , Laake Jeffrey L. , Ver Hoef Jay M.
Published: May 2009

SummaryWe consider a fully model‐based approach for the analysis of distance sampling data. Distance sampling has been widely used to estimate abundance (or density) of animals or plants in a spatially explicit study area. There is, however, no readily available method of making statistical inference on the relationships between abundance and environmental covariates. Spatial Poisson process likelihoods can be used to simultaneously estimate detection and intensity parameters by modeling distance sampling data as a thinned spatial point process. A model‐based spatial approach to distance sampling data has three main benefits: it allows complex and opportunistic transect designs to be employed, it allows estimation of abundance in small subregions, and it provides a framework to assess the effects of habitat or experimental manipulation on density. We demonstrate the model‐based methodology with a small simulation study and analysis of the Dubbo weed data set. In addition, a simple ad hoc method for handling overdispersion is also proposed. The simulation study showed that the model‐based approach compared favorably to conventional distance sampling methods for abundance estimation. In addition, the overdispersion correction performed adequately when the number of transects was high. Analysis of the Dubbo data set indicated a transect effect on abundance via Akaike's information criterion model selection. Further goodness‐of‐fit analysis, however, indicated some potential confounding of intensity with the detection function.
Gaussian Process Based Bayesian Semiparametric Quantitative Trait Loci Interval Mapping
Authors: Huang Hanwen , Zhou Haibo , Cheng Fuxia , Hoeschele Ina , Zou Fei
Published: May 2009

SummaryIn linkage analysis, it is often necessary to include covariates such as age or weight to increase power or avoid spurious false positive findings. However, if a covariate term in the model is specified incorrectly (e.g., a quadratic term misspecified as a linear term), then the inclusion of the covariate may adversely affect power and accuracy of the identification of quantitative trait loci (QTL). Furthermore, some covariates may interact with each other in a complicated fashion. We implement semiparametric models for single and multiple QTL mapping. Both mapping methods include an unspecified function of any covariate found or suspected to have a more complex than linear but unknown relationship with the response variable. They also allow for interactions among different covariates. This analysis is performed in a Bayesian inference framework using Markov chain Monte Carlo. The advantages of our methods are demonstrated via extensive simulations and real data analysis.
Foraging in precocial chicks of the black‐tailed godwitLimosa limosa: vulnerability to weather and prey size
Authors: Schekkerman Hans , Boele Arjan
Published: May 2009

Self‐feeding precocial development is associated with high energy requirements and potentially vulnerable to short‐term reductions in food availability, yet few studies have investigated development of foraging in precocial chicks and its sensitivity to environmental conditions. We studied time budgets and foraging behaviour during the 25‐d prefledging period in the insectivorous chicks of a grassland shorebird, the black‐tailed godwitLimosa limosa. Until 8–10 d old, parental brooding was the main determinant of chicks’ daily foraging time. Brooding decreased with age and temperature and increased during rainfall. Foraging time increased to 70–90% of the daylight period in chicks older than a week, during which distances of 3–12 km d−1were covered. Chicks took 98% of their arthropod prey from the grassland vegetation. Prey ingestion rates increased in the first week and slowly declined thereafter, modified by wind speed, temperature and time of day. Chicks in poor body condition were brooded more than chicks growing normally and hence had less feeding time, potentially leading to a negative condition spiral under adverse conditions. However, we found no effect of condition on prey ingestion rate that would preclude recovery when conditions improve. Combining behavioural observations with data on energy expenditure revealed that mean prey size was small (1–4.5 mg), necessitating a high feeding rate, but increased notably after 7–10 d of age. This coincided with a decrease in walking speed, suggesting that chicks fed more selectively. Prey of older chicks approached the upper limit of sizes available in exploitable densities in the grassland vegetation, and this enhances the chicks’ sensitivity to variation in prey availability due to weather and agricultural practice.
Real‐time quantitative PCR assay for measurement of avian telomeres
Authors: Criscuolo François , Bize Pierre , Nasir Lubna , Metcalfe Neil B. , Foote Chris G. , Griffiths Kate , Gault Elizabeth A. , Monaghan Pat
Published: May 2009

We present the application of a real‐time quantitative PCR assay, previously developed to measure relative telomere length in humans and mice, to two bird species, the zebra finchTaeniopygia guttataand the Alpine swiftApus melba. This technique is based on the PCR amplification of telomeric (TTAGGG)nsequences using specific oligonucleotide primers. Relative telomere length is expressed as the ratio (T/S) of telomere repeat copy number (T) to control single gene copy number (S). This method is particularly useful for comparisons of individuals within species, or where the same individuals are followed longitudinally. We used glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) as a single control gene. In both species, we validated our PCR measurements of relative telomere length against absolute measurements of telomere length determined by the conventional method of quantifying telomere terminal restriction fragment (TRF) lengths using both the traditional Southern blot analysis (Alpine swifts) and in gel hybridization (zebra finches). As found in humans and mice, telomere lengths in the same sample measured by TRF and PCR were well correlated in both the Alpine swift and the zebra finch.. Hence, this PCR assay for measurement of bird telomeres, which is fast and requires only small amounts of genomic DNA, should open new avenues in the study of environmental factors influencing variation in telomere length, and how this variation translates into variation in cellular and whole organism senescence.
Fatty acid signatures of female Brünnich's guillemots Uria lomvia suggests reliance on local prey for replacement egg production
Authors: Jacobs Shoshanah R. , Elliott Kyle H. , Gaston Anthony J. , Weber Jean‐Michel
Published: May 2009

The laying of smaller replacement eggs has been described as a time‐saving adaptation because chicks generally grow faster once hatched than inside the egg. However, chicks hatched from smaller eggs have, potentially, lower survival. Consequently, the smaller replacement egg represents a benefit to the female in terms of preserving its own condition at a cost to their offspring. We test these ideas by measuring adult mass changes and plasma lipid concentration changes in male and female Brünnich's guillemots Uria lomvia breeding on Coats Island, Nunavut. Though males lost more mass than females, these differences were not significant. Between laying the first and replacement egg, plasma fatty acid concentrations declined in females and increased in males, suggesting that females mobilise less lipid to preserve their condition after laying the replacement egg. In females, plasma lipid concentrations of the dominant fatty acids found in the eggs (16:0 and 18:1) declined between the laying of first and replacement eggs while plasma concentrations of 20:1 increased in both males and females. We compared the fatty acid signatures of first and replacement egg to look for evidence of differences between the lipid sources for their production. Principal component and discriminant function analyses showed that the fatty acid signatures of replacement eggs were closer to the signatures of the local prey than those of first eggs. We suggest that females rely on local sources of energy to a greater degree for the production of the replacement egg than the first egg, but that endogenous reserves of certain nutrients are important for the production of both eggs.
Numerical and dietary responses of a predator community in a temperate zone of Europe
Authors: Dupuy Gilles , Giraudoux Patrick , Delattre Pierre
Published: May 2009

The generalist predation hypothesis predicts that the functional responses of generalist predator species should be quicker than those of specialist predators and have a regulating effect on vole populations. New interpretations of their role in temperate ecosystems have, however, reactivated a debate suggesting generalist predators may have a destabilizing effect under certain conditions (e.g. landscape homogeneity, low prey diversity, temporary dominance of 1 prey species associated with a high degree of dietary specialization). We studied a rich predator community dominated by generalist carnivores (Martes spp., Vulpes vulpes, Felis catus) over a 6 yr period in farmland and woodland in France. The most frequent prey were small rodents (mostly Microtus arvalis, a grassland species, and Apodemus spp., a woodland species). Alternative prey were diverse and dominated by lagomorphs (Oryctolagus cuniculus, Lepus europeus). We detected a numerical response among specialist carnivores but not among generalist predators. The dietary responses of generalist predators were fairly complex and most often dependent on variation in density of at least 1 prey species. These results support the generalist predation hypothesis. We document a switch to alternative prey, an increase of diet diversity, and a decrease of diet overlap between small and medium‐sized generalists during the low density phase of M. arvalis. In this ecosystem, the high density phases of small mammal species are synchronous and cause a temporary specializing of several generalist predator species. This rapid functional response may indicate the predominant role of generalists in low amplitude population cycles of voles observed in some temperate areas.
Breeding like rabbits: global patterns of variability and determinants of European wild rabbit reproduction
Authors: Tablado Zulima , Revilla Eloy , Palomares Francisco
Published: May 2009

The importance of European wild rabbitsOryctolagus cuniculusboth as a pest in some areas and as a key prey species in others emphasizes the need to understand what controls its population dynamics worldwide. In this study we aim to describe the variability in rabbit breeding parameters and identify the main factors that govern it at a global scale. Despite the species’ wide distribution, some reproductive traits such as short sexual maturity age, duration of gestation period, and existence of post‐partum oestrus are similar in all populations conferring the species a high breeding potential. Nevertheless, other aspects vary substantially among regions resulting in highly different population productivities and also across years. These latter parameters are the length of breeding season, proportion of pregnant females, age of first reproduction, and number and size of litters. Our results show that variability in these attributes is mainly affected by a combination of environmental controls (i.e. temperature, resource availability, and photoperiod) and individual properties (age and body weight). On the other hand, the effect of other factors such as population density could not be demonstrated. Knowledge about the factors driving global reproduction patterns of European wild rabbits will improve our understanding about their population dynamics, and thus will help to optimize the management and conservation of their populations.
Could native predators help to control invasive fishes? Microcosm experiments with the Neotropical characid, Brycon orbignyanus
Authors: Santos A. F. G. N. , Santos L. N. , García‐Berthou E. , Hayashi C.
Published: May 2009

Abstract –  The potential of the native characid, Brycon orbignyanus, to help to control some invasive fish species currently present in the Paraná River basin was addressed through microcosm experiments. Juveniles of three invasive (Cichla piquiti, Oreochromis niloticus and Ictalurus punctatus) and two native (Astyanax altiparanae and Prochilodus lineatus) fish species were offered as prey to B. orbignyanus in 300‐l aquarium trials with three habitat complexity treatments (0%, 50% and 100% structure). Prey survival was much more variable among species (I. punctatus < C. piquiti < O. niloticus∼P. lineatus∼A. altiparanae) than through time, and B. orbignyanus predation was clearly mediated by habitat complexity, with lower prey survival in low‐complexity treatments. The lower survival observed for C. piquiti could be partially explained by its less active behaviour and its preference for a surface microhabitat and less structured areas. Prey size also affected predation rates, as for the three less consumed species the largest individuals were significantly preyed on. Our results suggest that preserving and restoring the populations of B. orbignyanus might help to control some fish species introduced to the Paraná River basin, particularly I. punctatus and C. piquiti.
Which mothers wean their babies prematurely from full breastfeeding? An Australian cohort study
Authors: Baxter Jennifer , Cooklin Amanda R , Smith Julie
Published: May 2009

Aim:  To identify the maternal and infant characteristics associated with an early transition from full breastfeeding to complementary or no breastfeeding during the first 2 months of life in a large, representative cohort of Australian infants.

Method:  Multinomial logistic modelling was performed on data for infants with complete breastfeeding and sociodemographic data (N = 4679) including maternal age, education, smoking, employment, pregnancy and birth outcomes.

Results:  Ninety‐one percent of women initiated breastfeeding. Sixty‐nine percent of infants were being fully breastfed at 1 month, and 59% were fully breastfed at 2 months. Maternal characteristics – age less than 25 years, smoking in pregnancy, early full‐time postnatal employment and less educational attainment – were associated with early breastfeeding cessation. Infant factors – multiple birth, caesarean birth, infant or first birth – were associated with a transition to complementary breastfeeding in the first postnatal month.

Conclusion:  Breastfeeding duration is substantially affected by breastfeeding outcomes in the first postpartum month. The first month is an important window for evidence‐based interventions to improve rates of full breastfeeding in groups of women identified as at risk of early breastfeeding cessation.
Neonatal cholestasis: differentiation of biliary atresia from neonatal hepatitis in a developing country
Authors: Poddar Ujjal , Thapa Babu Ram , Das Ashim , Bhattacharya Anish , Rao KL Narasimha , Singh Kartar
Published: May 2009

Aim:  To study the accuracy of various clinical and investigational parameters to differentiate biliary atresia (BA) from neonatal hepatitis (NH).

Methods:  It was a prospective study, conducted in a tertiary care hospital. A total 101 infants with neonatal cholestasis (NCS) were included in this study. Following a baseline hepatobiliary scintigraphic study (HBS), it was repeated after giving UDCA (40 mg/kg/day for 48–72 h). The sensitivity and specificity of clinical and investigational parameters were calculated with peroperative cholangiogram as gold standard.

Results:  The mean age was 2.8 ± 1.7 months and 82 were male. Of these, 35 were diagnosed to have BA and 66 had NH (idiopathic 25, sepsis/UTI 20, galactosaemia 11, TORCH 2 and others 8). Persistently clay stool was found to have modest accuracy (79%) and the accuracy of HBS improved significantly following UDCA therapy (91% from 77%, p < 0.01) whereas liver biopsy was 100% accurate in differentiating BA from NH. The outcome of BA cases with ductal plate malformation (DPM) was worse.

Conclusion:  One‐third of all NCS in India is due to BA and among the intrahepatic causes acquired infection and galactosaemia are common. Liver biopsy is the best method to differentiate NH from BA.