bluuebunny/crossref_metadata_2025 huggingface dataset:
Switching between tasks and responses: a developmental study
Authors: Crone Eveline A. , Bunge Silvia A. , Van Der Molen Maurits W. , Ridderinkhof K. Richard
Published: April 2006

Task switching requires the ability to flexibly switch between task rules and responses, and is sensitive to developmental change. We tested the hypothesis that developmental changes in task switch performance are associated with changes in the facilitating or interfering effect of the previously retrieved stimulus–response (S–R) association. Three age groups (7–8‐year‐olds, 10–12‐year‐olds and 20–25‐year‐olds) performed a two‐choice reaction time (RT) task in which spatially compatible or incompatible responses were required. The RT costs associated with switching between tasks were larger when responses were repeated than when responses were alternated. Younger children showed a greater cost than adults when switching between tasks but repeating responses. This age difference decreased when the interval between the previous response and the upcoming stimulus increased. Switch costs were larger when switching to the compatible task than to the incompatible task, but this effect did not differ between age groups. These findings suggest that young children build up stronger transient associations between task sets and response sets, which interfere with their ability to switch to currently intended actions. A similar pattern has previously been observed for older adults (Mayr, 2001), suggesting a common contributor to task switching deficits across the life span.
The face behind the mask: a developmental study
Authors: Tottenham Nim , Leon Andrew C. , Casey B.J.
Published: April 2006

Faces are a rich and available source of social information, and the representation for faces is robust in adults (i.e. the face detection effect; Purcell & Stewart, 1988). The current study compared the developmental trajectory of the robustness of face perception against the trajectory for a non‐face object. Participants (5–35 years old) were presented with rapid (17 and 33 millisecond) presentations of face and house stimuli and were instructed to identify the object category of the stimulus (face or house). There was an interaction between object type and age such that the developmental slope for face identification was steeper than the slope for house identification for the 17‐millisecond presentation. These data show that faces are processed in a different way than a non‐face object during the period from middle childhood through adolescence and adulthood, and this differential processing may involve the massive amount of exposure we have to faces.
When the social mirror breaks: deficits in automatic, but not voluntary, mimicry of emotional facial expressions in autism
Authors: McIntosh Daniel N. , Reichmann‐Decker Aimee , Winkielman Piotr , Wilbarger Julia L.
Published: April 2006

Humans, infants and adults alike, automatically mimic a variety of behaviors. Such mimicry facilitates social functioning, including establishment of interpersonal rapport and understanding of other minds. This fundamental social process may thus be impaired in disorders such as autism characterized by socio‐emotional and communicative deficits. We examined automatic and voluntary mimicry of emotional facial expression among adolescents and adults with autistic spectrum disorders (ASD) and a typical sample matched on age, gender and verbal intelligence. Participants viewed pictures of happy and angry expressions while the activity over their cheek and brow muscle region was monitored with electromyography (EMG). ASD participants did not automatically mimic facial expressions whereas the typically developing participants did. However, both groups showed evidence of successful voluntary mimicry. The data suggest that autism is associated with an impairment of a basic automatic social‐emotion process. Results have implications for understanding typical and atypical social cognition.
The effect of divided attention on inhibiting the gravity error
Authors: Hood Bruce M. , Wilson Alice , Dyson Sally
Published: April 2006

Children who could overcome the gravity error on Hood's (1995) tubes task were tested in a condition where they had to monitor two falling balls. This condition significantly impaired search performance with the majority of mistakes being gravity errors. In a second experiment, the effect of monitoring two balls was compared in the tubes task and a spatial transposition task not involving gravity. Again, monitoring two objects produced impaired search performance in the gravity task but not in the spatial transposition task. These findings support the view that divided attention disrupts the ability to exercise inhibitory control over the gravity error and that the performance drop on this task is not due to the additional task demands incurred by divided attention.
Crossmodal integration of emotional information from face and voice in the infant brain
Authors: Grossmann Tobias , Striano Tricia , Friederici Angela D.
Published: April 2006

We examined 7‐month‐old infants’ processing of emotionally congruent and incongruent face–voice pairs using ERP measures. Infants watched facial expressions (happy or angry) and, after a delay of 400 ms, heard a word spoken with a prosody that was either emotionally congruent or incongruent with the face being presented. The ERP data revealed that the amplitude of a negative component and a subsequent positive component in infants’ ERPs varied as a function of crossmodal emotional congruity. An emotionally incongruent prosody elicited a larger negative component in infants’ ERPs than did an emotionally congruent prosody. Conversely, the amplitude of infants’ positive component was larger to emotionally congruent than to incongruent prosody. Previous work has shown that an attenuation of the negative component and an enhancement of the later positive component in infants’ ERPs reflect the recognition of an item. Thus, the current findings suggest that 7‐month‐olds integrate emotional information across modalities and recognize common affect in the face and voice.
The shape of boubas: sound–shape correspondences in toddlers and adults
Authors: Maurer Daphne , Pathman Thanujeni , Mondloch Catherine J.
Published: April 2006

A striking demonstration that sound–object correspondences are not completely arbitrary is that adults map nonsense words with rounded vowels (e.g. bouba) to rounded shapes and nonsense words with unrounded vowels (e.g. kiki) to angular shapes (Köhler, 1947; Ramachandran & Hubbard, 2001). Here we tested the bouba/kiki phenomenon in 2.5‐year‐old children and a control group of adults (n =20 per age), using four pairs of rounded versus pointed shapes and four contrasting pairs of nonsense words differing in vowel sound. Overall, participants at both ages matched words with rounded vowels to the rounder shapes and words with unrounded vowels to the pointed shapes (both ps < .0005), with no significant difference between the two ages (p > .10). Such naturally biased correspondences between sound and shape may influence the development of language.
Choose and choose again: appearance–reality errors, pragmatics and logical ability
Authors: Deák Gedeon O. , Enright Brian
Published: April 2006

In the Appearance/Reality (AR) task some 3‐ and 4‐year‐old children make perseverative errors: they choose the same word for the appearance and the function of a deceptive object. Are these errors specific to the AR task, or signs of a general question‐answering problem? Preschoolers completed five tasks: AR; simple successive forced‐choice question pairs (QP); flexible naming of objects (FN); working memory (WM) span; and indeterminacy detection (ID). AR errors correlated with QP errors. Insensitivity to indeterminacy predicted perseveration in both tasks. Neither WM span nor flexible naming predicted other measures. Age predicted sensitivity to indeterminacy. These findings suggest that AR tests measure a pragmatic understanding; specifically, different questions about a topic usually call for different answers. This understanding is related to the ability to detect indeterminacy of each question in a series. AR errors are unrelated to the ability to represent an object as belonging to multiple categories, to working memory span, or to inhibiting previously activated words.
Subsistence Response to Market Shocks
Authors: Dyer George A. , Boucher Steve , Taylor J. Edward
Published: April 2006

Microeconomic models posit that transaction costs isolate subsistence producers from output market shocks. We integrate microeconomic models of many heterogeneous households into a general equilibrium model and show that supply on subsistence farms may respond, in apparently perverse ways, to changes in output market prices. Price shocks in markets for staple goods are transmitted to subsistence producers through interactions in factor markets. In the case presented, a decrease in the market price of maize reduces wages and land rents, stimulating maize production by subsistence households; however, real incomes of subsistence households fall.
How Firms Construct Price Changes: Evidence from Restaurant Responses to Increased Minimum Wages
Authors: MacDonald James M. , Aaronson Daniel
Published: April 2006

We use price data underlying the Consumer Price Index to assess how restaurants, whose prices are generally quite sticky, respond to minimum wage increases. Aggregate prices rise, quickly, by amounts reflecting the increase in costs, and they rise more among fast food outlets and in low‐wage locations. But restaurants do not construct price increases by raising all their prices by amounts reflecting the increase in wages. Instead, they raise only some prices, but by larger amounts. Prices at cluster points are less likely to be changed, and prices that were recently increased (decreased) are less (more) likely to be raised.
An Ordered Tobit Model of Market Participation: Evidence from Kenya and Ethiopia
Authors: Bellemare Marc F. , Barrett Christopher B.
Published: April 2006

Do rural households in developing countries make market participation and volume decisions simultaneously or sequentially? This article develops a two‐stage econometric method to test between these two competing hypotheses regarding household‐level marketing behavior. The first stage models the household's choice of whether to be a net buyer, autarkic, or a net seller in the market. The second stage models the quantity bought (sold) for net buyers (sellers) based on observable household characteristics. Using household data from Kenyan and Ethiopian livestock markets, we find evidence in favor of sequential decision making, the welfare implications of which we discuss.
The Economics of Administering Import Quotas with Licenses‐on‐Demand in Agriculture
Authors: Hranaiova Jana , de Gorter Harry , Falk James
Published: April 2006

A Nash equilibrium is determined for licenses‐on‐demand import quotas where licenses are allocated on a prorated basis. Inefficiency is incurred because licenses are allocated to high‐cost firms. The ability to overbid exacerbates the inefficiency due to proportionate reductions in licenses. Quota expansion causes high‐cost firms to decrease their bids but reduces inefficiency. The entry of a new firm causes all incumbent firms to increase bids or bid the quota. Not penalizing firms for the non‐use of licenses increases inefficiency. The inefficiency impacts of tariff reductions, license fees, limits per firm, and imperfect information are also addressed.
Short‐ and Long‐Run Credit Constraints in French Agriculture: A Directional Distance Function Framework Using Expenditure‐Constrained Profit Functions
Authors: Blancard Stéphane , Boussemart Jean-Philippe , Briec Walter , Kerstens Kristiaan
Published: April 2006

This empirical application investigates the eventual presence of credit constraints using a panel of French farmers. The credit‐constrained profit maximization model proposed by Färe, Grosskopf, and Lee is extended in three ways. First, we rephrase the model in terms of directional distance functions to allow duality with the profit function. Second, we model credit constraints in the short‐run and investment constraints in the long‐run using short‐ and long‐run profit functions. Third, we lag the expenditure constraint one year to account for the separation between planning and production. We find empirical evidence of credit and investment constraints. Financially unconstrained farmers are larger, perform better, and seem to benefit from a virtuous circle where access to financial markets allows better productive choices.
Estimating the Prevalence and Cost of Yield‐Switching Fraud in the Federal Crop Insurance Program
Authors: Atwood Joseph A. , Robison-Cox James F. , Shaik Saleem
Published: April 2006

Producers who manipulate and switch their reported crop‐yields between separately insured units can increase their insurance indemnities substantially. A statistical model that identifies potential yield switching is developed. The unrestricted statistical model is singular and is identified by imposing a mixture of system‐estimable and system‐nonestimable restrictions. Lower bound estimates of yield‐switching fraud incidence and costs are obtained by applying the model to 207,067 multiple unit producers who purchased crop insurance in 1998.
Government Payments and Farm Business Survival
Authors: Key Nigel , Roberts Michael J.
Published: April 2006

Using farm‐level panel data from recent U.S. Agricultural Censuses, this study examines how direct government payments influence the survival of farm businesses, paying particular attention to the differential effect of payments across farm‐size categories. A Cox proportional hazards model is used to estimate the effect of government payments on the instantaneous probability of a farm business failure, controlling for farm and operator characteristics. Results indicate that an increase in government payments has a small but statistically significant negative effect on the rate of business failure, and the magnitude of this effect increases with farm size.
The Impact of Coupled and Decoupled Government Subsidies on Off‐Farm Labor Participation of U.S. Farm Operators
Authors: Ahearn Mary Clare , El-Osta Hisham , Dewbre Joe
Published: April 2006

With the 1996 Farm Act, the United States introduced payments that were designed to be “decoupled.” Labor allocation choices are likely to be affected by receipt of payments, and income from off‐farm jobs has been the major source of income for most farm households for sometime. This article examines whether the 1996 change has affected the off‐farm labor participation of farm households. We conclude that the observed increase in off‐farm participation of farm operators who received payments was not the result of the 1996 policy change. Government payments, whether coupled or decoupled, have a negative effect on off‐farm labor participation.
Developing Experience‐Based Premium Rate Discounts in Crop Insurance
Authors: Rejesus Roderick M. , Coble Keith H. , Knight Thomas O. , Jin Yufei
Published: April 2006

This article addresses the feasibility of implementing an experience‐based premium rate discount system in crop insurance. While adverse selection and moral hazard in crop insurance have been extensively studied in the past, discount systems or bonus‐malus incentives have not, to our knowledge, been investigated. Our empirical analysis indicates that a crop insurance discount system could be implemented based on a measure of favorable past insurance experience. The estimated average discounts based on the rating methods developed in this study ranged from 5% to 9% (depending on the crop being considered).
A Political Economic Analysis of U.S. Rice Export Programs to Japan and South Korea: A Game‐Theoretic Approach
Authors: Lee Dae-Seob , Kennedy P. Lynn
Published: April 2006

The Uruguay Round Agreement on agriculture has contributed to the increase in U.S. and world rice trade since 1994. Despite this, the Japanese and Korean rice markets continue to be characterized by high levels of trade intervention. This article attempts to analyze both import markets incorporating econometric estimates and public choice theory in a game‐theoretic framework. Various scenarios are analyzed. The results show that the overall Nash equilibrium occurs with a 4% tariff reduction for Japan and Korea under the U.S. Market Development Program, which includes the Market Access Program and Foreign Market Development Program.
Rejecting New Technology: The Case of Genetically Modified Wheat
Authors: Berwald Derek , Carter Colin A. , Gruère Guillaume P.
Published: April 2006

Canada has stringent regulations covering the release of new wheat varieties, but the United States has virtually no regulations in this area. Monsanto Co. developed genetically modified (GM) spring wheat for North America, and made a commitment to the U.S. industry to release this new technology simultaneously in both Canada and the United States, or not at all. The Canadian regulatory bias against new varieties acted as a veto against GM wheat and caused Monsanto to shelve the technology in both countries in 2004. Substantial economic rents were foregone in North America due to the rejection of this new technology.
The Effect of Initial Endowments in Experimental Auctions
Authors: Corrigan Jay R. , Rousu Matthew C.
Published: April 2006

We report the results of an experiment designed to test whether initial endowments affect value estimates elicited from experimental auctions. Comparing bids for one unit of a good, two units of a good, and a second unit of a good when endowed with the first unit, we find that willingness to pay for the second unit of a good is, on average, as much as 75% higher when endowed with the first unit. We go on to advance two theories that could potentially reconcile our results with neoclassical consumer theory.
Factors Influencing Illinois Farmland Values
Authors: Huang Haixiao , Miller Gay Y. , Sherrick Bruce J. , Gómez Miguel I.
Published: April 2006

A hedonic model of Illinois farmland values is estimated using county‐level cross‐section time‐series data. Explanatory variables include land productivity, parcel size, improvements, distances to Chicago and other large cities, an urban‐rural index, livestock production through swine operation scale and farm density measures, population density, income, and inflation. The inclusion of spatial and serial correlation components substantially improves the model fit. Farmland values decline with parcel size, ruralness, distance to Chicago and large cities, and swine farm density, and increase with soil productivity, population density, and personal income.
Is Site‐Specific Yield Response Consistent over Time? Does It Pay?
Authors: Liu Yanyan , Swinton Scott M. , Miller Neil R.
Published: April 2006

This study examines the profitability and stability of site‐specific (SS) nitrogen fertilizer recommendations using an empirical model of SS yield response to controlled inputs, stable site characteristics, and time‐varying weather factors. Using a three‐year panel of on‐farm corn yield experiments and new, continuous variables to describe site characteristics, both spatial and ordinary least squares regression models show clear evidence of SS corn yield response to nitrogen fertilizer. Yield response is predictable only on irrigated fields. Even there, bootstrapped confidence intervals for profitability gains on selected fields indicate that SS nitrogen application would rarely cover its costs.
Show Me the Money! The Value of College Graduate Attributes as Expressed by Employers and Perceived by Students
Authors: Norwood F. Bailey , Henneberry Shida Rastegari
Published: April 2006

Employers of agricultural undergraduates are presented with hypothetical job candidates with different attributes and salaries, and are asked which candidate, if any, they would hire. The employer choices are then used to estimate the additional salary they will pay for undergraduates with certain attributes. Students are administered similar surveys where they indicate which hypothetical candidate they think will be hired, which can be used to estimate students' perceived salary increase associated with each attribute. Employers' stated values are then compared to students' perceived values to identify any misperceptions regarding the monetary return of select attributes.
Specification and Estimation of Production Functions Involving Damage Control Inputs: A Two‐Stage, Semiparametric Approach
Authors: Kuosmanen Timo , Pemsl Diemuth , Wesseler Justus
Published: April 2006

Productivity assessment of damage control inputs (such as pesticides) is complicated because their effect depends on the exposure to damage agents (such as pests). We discuss some open specification and estimation issues. The contribution is threefold. First, we elaborate the separability conditions for the damage control function and production function. Second, we employ a two‐stage semiparametric technique to combine attractive features of both nonparametric and parametric approaches. Third, we model the interaction between pest exposure and damage control inputs by using slope dummies. An application to productivity analysis of small scale Bt cotton production in China illustrates the approach.
Slippage in the Conservation Reserve Program or Spurious Correlation? A Rejoinder
Authors: Roberts Michael J. , Bucholz Shawn
Published: April 2006

The Conservation Reserve Program (CRP) pays farmers about $2 billion per year to retire cropland under ten‐ to fifteen‐year contracts. Recent research by Wu (2000) found that slippage—an unintended stimulus of new plantings—offsets some of CRP's environmental benefits. In a comment on Wu, we argued CRP enrollments were endogenous and confounded by omitted variables. In his reply, Wu (2005) used results from a Hausman test to argue that CRP enrollments are exogenous. In this rejoinder, we explain why the candidate instrument (erodibility) is likely confounded by omitted variables, so Wu's use of the Hausman test is uninformative.
PIT‐DIGGING, OCCUPATION AND STRUCTURED DEPOSITION ON RUDSTON WOLD, EASTERN YORKSHIRE
Authors: HARDING JAN
Published: April 2006

Summary. Excavated Neolithic pit clusters, like those found on Rudston Wold in eastern Yorkshire, have often been seen as the remains of occupation sites. The features are interpreted as possessing practical roles, including their use for storing grain, and the incorporated material culture regarded as casually discarded waste. More recent interpretations, however, have emphasized these features’ functional unsuitability, rather seeing pit‐digging, and the deposition of ideologically‐charged objects, as a deliberate attempt to inscribe meaning across a landscape. These two different approaches are considered by a detailed examination of the Peterborough Ware and Grooved Ware associated pits, dug‐out swallow‐holes and hollows of Rudston Wold. It is argued that their lithic assemblage demonstrates a conventionality best understood as representing occupation at and around the features, themselves once part of small‐scale dwellings, but that this material nonetheless resulted from deliberate and purposeful acts which changed during the later Neolithic.
POTS, HOUSES AND METAL: TECHNOLOGICAL RELATIONS AT THE BRONZE AGE TELL AT SZÁZHALOMBATTA, HUNGARY
Authors: SOFAER JOANNA
Published: April 2006

Summary.  At the Bronze Age tell of Százhalombatta, Hungary, techniques used for making pottery echo those used in other media. Pottery and architecture have a close relationship. Not only were both made of clay, but methods of making pots echo those used for building. Similarly, pottery and metalwork share common themes and technologies for working with clay and bronze. Since choices made by potters are not solely confined to the environment, raw materials and tools, but are also socially and culturally defined, by implication the transfer of know‐how must be situated within social networks between people. This paper considers how the identification of technical relationships between different media at Százhalombatta can be used to explore social relations in Bronze Age society, thereby suggesting relationships that work on both technical and social levels.
WEALTH AND STATUS IN IRON AGE KNOSSOS
Authors: KOTSONAS ANTONIS
Published: April 2006

Summary.  Knossos Tekke tomb 2 is one of the richest tombs in the Iron Age Aegean, renowned for its deposits of gold. The tomb is widely attributed to a family of goldsmiths, who migrated to Knossos from the Near East. This article, however, questions this attribution. An alternative interpretation is pursued through surveys of the distribution of some luxury materials, amply represented in the Tekke tomb, in all known Knossian tombs. By setting the Tekke find against the large corpus of Knossian burial material, I identify the Tekke occupants as members of a local élite. This group is shown to have had privileged access to the products of a goldsmith's workshop, as well as to the sources of some lavish, mostly imported, raw materials, and to have regulated their distribution within Knossian society during the eighth century. The means through which the Tekke élite claimed and defended their wealth and status are assessed and their possible Late Bronze Age pedigree is conjectured.
THE CULTURAL BIOGRAPHY OF A PHOENICIAN MUSHROOM‐LIPPED JUG
Authors: FLETCHER RICHARD
Published: April 2006

Summary. This paper is the biography of a single piece of pottery found in a tomb in Sardinia. The form is one that is common in Levantine sites in the Mediterranean in the Early Iron Age, but this single vessel, its history, context, and form, allows a greater story to be told: it points to a second wave of Levantine exploration and colonization – probably Tyrian – that built upon a Euboean–northern Phoenician initial phase in the eighth century BC.
EARLY EUBOEAN SETTLEMENTS IN THE CARTHAGE AREA
Authors: BOARDMAN JOHN
Published: April 2006

Summary.  There is growing archaeological evidence that Greeks and Phoenicians cooperated, or at least were not serious rivals in early days of exploration of the western Mediterranean, before the sixth‐century trade wars, even to the point of settling side‐by‐side. The geographical, textual and material evidence for Greek presence close to, and at Carthage in early days is here reviewed.
ROMANO‐BRITISH PEOPLE AND THE LANGUAGE OF SOCIOLOGY
Authors: McCARTHY MIKE
Published: April 2006

Summary.  Despite the vast amount of work and the huge database for Roman Britain, the people of the province remain very difficult to discern. There are many reasons for this, but one is that we have not yet learned to look behind the disjecta membra of archaeology in order to understand the structure and nature of society, and how the Roman Conquest may have impacted upon it. The language of sociology offers scope for thought, especially when combined with examples drawn from historically documented societies in later periods. Whilst models drawn from the classical world are important, attention also needs to be focused on the local, and on the factors that determined the shape of people's lives and influenced their daily activities. Not all these are archaeologically detectable; nevertheless an appreciation of their existence is an important pre‐requisite in attempting explanations of patterns in the data.
The Good, the Bad and the Ugly: The Media in Prison Films
Authors: BENNETT JAMIE
Published: April 2006

Abstract: Generally, people have low levels of exposure to prisons through personal experience and therefore the media plays an important role in informing beliefs and actions. In particular prison films are an important and extensive form of media depiction. However, media depiction of crime and imprisonment has been criticised on ethical, political and social grounds. This article explores how prison films have depicted the relationship between the media, crime and punishment. It argues that this is a significant and integrated part of the prison film genre. It also argues that these representations are important both as a narrative device and in making the media a focus of pressure for reform.
Frequency of Man‐Made Disasters in the 20th Century
Authors: Coleman Les
Published: April 2006

This paper analyses two disaster databases maintained by the Center for Research on the Epidemiology of Disasters and by Emergency Management Australia. The objective is to quantify the frequency, nature and changes in man‐made disasters in industrialised countries during the past century. The analysis shows an exponential growth in disaster frequency, largely due to an increase in traditional hazards such as fires and explosions, rather than from new technologies. Although the number of incidents has grown, this has been offset by a decline in fatalities per incident. An important implication of these results is that regulatory oversight and internal corporate governance processes are inadequate to ensure effective management of modern industrial risks.
Small Business in the Face of Crisis: Identifying Barriers to Recovery from a Natural Disaster1
Authors: Runyan Rodney C.
Published: April 2006

The crisis management literature has not dealt in depth with small business response to disasters. This study takes a qualitative approach to consider how small businesses respond to and recover from a large disaster, by interviewing stakeholders in five different communities in the Gulf Coast of the United States. Events that are considered to be crises in nature are usually characterized by high consequence, low probability, ambiguity, and decision making time pressure. Hurricane Katrina and its aftermath caused small business owners in the U.S. Gulf region to experience each of these. Findings include lack of planning by small business; vulnerability to cash flow interruption; lack of access to capital for recovery; problems caused by federal assistance; and serious infrastructure problems impeding recovery.
Decision Making Effectiveness in Wildfire Incident Management Teams
Authors: McLennan Jim , Holgate Alina M. , Omodei Mary M. , Wearing Alexander J.
Published: April 2006

During large scale wildfires, suppression activities are carried out under the direction of an Incident Management Team (IMT). The aim of the research was to increase understanding of decision processes potentially related to IMT effectiveness. An IMT comprises four major functions: Command, Operations, Planning, and Logistics. Four methodologies were used to study IMT processes: computer simulation experiments; analyses of wildfire reports; interviews with IMT members; and cognitive ethnographic studies of IMTs. Three processes were important determinants of IMT effectiveness: information management and cognitive overload; matching component function goals to overall goals; and team metacognition to detect and counter task‐disruptive developments. These processes appear to be complex multi‐person analogues of individual Incident Command processes identified previously. The findings have implications for issues such as: creating IMTs; training IMTs; managing IMTs; and providing decision support to IMTs.
Organisational Issues in Implementing an Information Sharing Framework: Lessons from the Matata Flooding Events in New Zealand
Authors: Dantas André , Seville Erica
Published: April 2006

This paper presents a critical review and analysis of issues in implementing electronic data and information sharing frameworks for organisations involved in response activities during disaster. An implementation focused approach is used to understand end‐user needs and develop tools that meet their operational requirements. A case study of New Zealand roading organisations examines how information is currently shared both within and between organisations to support crisis decision‐making, and the potential benefits and implications of enhanced data and information sharing frameworks. Preliminary results show that considerable performance gains in response activities during disasters can be achieved provided technology is designed to work with and enhance existing operating structures.
Infrequent, but not frequent, reinforcers produce more variable responding and deficient sustained attention in young children with attention‐deficit/hyperactivity disorder (ADHD)
Authors: Aase Heidi , Sagvolden Terje
Published: April 2006

Background:  The underlying behavioral/psychological processes of attention‐deficit/hyperactivity disorder are unclear. Motivational factors, related to dopamine dysfunction, may play an important role in the development of the behavioral symptoms. Particularly, infrequent, but not frequent, reinforcers have been suggested to be associated with altered responding and deviant behavior in children with ADHD. The present study was designed to analyze the influence of reinforcement frequency on operationalized measures of hyperactivity, impulsiveness, sustained attention, and response variability.

Methods:  Fifty‐six boys, half of whom were diagnosed with ADHD, completed a computerized task presented as a game with two squares on the screen. One square was associated with reinforcement. The task required responses by the computer mouse under contingencies alternating between variable interval schedules of short (mean 2 s) and long (mean 20 s) durations. Reinforcers were cartoon pictures and small trinkets.

Results:  Overall, there was no difference between children with ADHD and comparison children when reinforcers were given frequently. Statistically significant differences on measures of sustained attention and variability, but not hyperactivity and impulsiveness, were found during infrequent reinforcement only. Age effects interacted with group effects on sustained attention, showing that group differences were found in the young children only. Surprisingly, older comparison children showed increased response variability and no learning.

Conclusions:  When reinforcers are infrequent, children with ADHD show deficient sustained attention and increased variability in responding. Computer experience may have interfered with measures of hyperactivity and impulsiveness. The unexpectedly poor performance of the older comparison children may have been due to inefficient reinforcers or to verbally governed behavior overruling reinforcer effects. Reinforcer characteristics and experimental procedures are important factors influencing findings in studies investigating motivational factors. The study provides some support for the dynamic developmental theory of ADHD predicting relationships between neurobiological deficits, altered reinforcement mechanisms, and treatment recommendations.
Assessing medication effects in the MTA study using neuropsychological outcomes
Authors: Epstein Jeffery N. , Keith Conners C. , Hervey Aaron S. , Tonev Simon T. , Eugene Arnold L. , Abikoff Howard B. , Elliott Glen , Greenhill Laurence L. , Hechtman Lily , Hoagwood Kimberly , Hinshaw Stephen P. , Hoza Betsy , Jensen Peter S. , March John S. , Newcorn Jeffrey H. , Pelham William E. , Severe Joanne B. , Swanson James M. , Wells Karen , Vitiello Benedetto , Wigal Timothy ,   the MTA Cooperative Study Group
Published: April 2006

Background:  While studies have increasingly investigated deficits in reaction time (RT) and RT variability in children with attention deficit/hyperactivity disorder (ADHD), few studies have examined the effects of stimulant medication on these important neuropsychological outcome measures.

Methods:  316 children who participated in the Multimodal Treatment Study of Children with ADHD (MTA) completed the Conners’ Continuous Performance Test (CPT) at the 24‐month assessment point. Outcome measures included standard CPT outcomes (e.g., errors of commission, mean hit reaction time (RT)) and RT indicators derived from an Ex‐Gaussian distributional model (i.e., mu, sigma, and tau).

Results:  Analyses revealed significant effects of medication across all neuropsychological outcome measures. Results on the Ex‐Gaussian outcome measures revealed that stimulant medication slows RT and reduces RT variability.

Conclusions:  This demonstrates the importance of including analytic strategies that can accurately model the actual distributional pattern, including the positive skew. Further, the results of the study relate to several theoretical models of ADHD.
Child–therapist and parent–therapist alliance and therapeutic change in the treatment of children referred for oppositional, aggressive, and antisocial behavior
Authors: Kazdin Alan E. , Whitley Moira , Marciano Paul L.
Published: April 2006

Background:  We examined the therapeutic alliance in evidence‐based treatment for children (N = 77, 19 girls, 58 boys, ages 6–14) referred clinically for oppositional, aggressive, and antisocial behavior.

Method:  Different alliances (child–therapist, parent–therapist) were assessed from each participant's perspective at two points over the course of treatment. Both the quality of the child–therapist and the parent–therapist alliance predicted therapeutic changes in the children; the parent–therapist alliance also predicted improvements in parenting practices in the home.

Results:  The findings could not easily be attributed to the influence of other domains (socioeconomic disadvantage, parent psychopathology and stress, and severity of child dysfunction) known to predict therapeutic change or to rater effects (common rater variance) in the predictors and criteria.

Conclusion:  The therapeutic alliance warrants increased attention to understand the precise role in treatment and whether or how the alliance can be mobilized to enhance change.
Annotation: The therapeutic alliance – a significant but neglected variable in child mental health treatment studies
Authors: Green Jonathan
Published: April 2006

Background:  There has been relatively little research into therapeutic alliance in child and adolescent mental health and virtually no incorporation of alliance measures as a variable in treatment trials in Child and Adolescent Mental Health Services (CAMHS).

Method:  A selective literature review on studies in therapeutic alliance in adulthood and childhood along with a theoretical formulation of possible mechanisms of alliance.

Results:  Therapeutic alliance is reliably measurable both by observation and questionnaire methods at all points in the treatment cycle. In both adult and child studies it shows a consistent, albeit modest, association with treatment outcome. In specific adult studies it has shown a high predictive validity in relation to outcome compared to other variables. In child studies alliance is particularly salient in externalising disorder and predicts outcome of inpatient treatment. Child alliance and parental alliance are independent factors. Theoretical models of alliance outlined in this paper suggest testable hypotheses regarding predictors for positive and negative alliance.

Conclusions:  Therapeutic alliance in CAMHS is measurable and worth measuring. It is likely to be an important variable for treatment outcome studies and should be included in future trial designs.
Predictors of between‐family and within‐family variation in parent–child relationships
Authors: O'Connor Thomas G. , Dunn Judy , Jenkins Jennifer M. , Rasbash Jon
Published: April 2006

Background:  Previous studies have found that multiple factors are associated with parent–child relationship quality, but have not distinguished potential sources of between‐family and within‐family variation in parent–child relationship quality.

Methods:  Approximately equal numbers of biological (non‐stepfamilies), single‐mother, stepfather, and complex/stepmother stepfamilies were selected from a large community study in England. The sample comprised 404 children in 171 families. Parent–child warmth/support and conflict/negativity were assessed using questionnaire and interview methods; family socio‐demographic data were collected from parent report.

Results:  Multilevel model analyses indicated substantial within‐family variation in parent–child relationship quality, and greater within‐family variation in complex/stepmother families compared to other family types. Within‐family variation was largely accounted for by differences in the siblings’ biological relatedness to the mother and father and to child‐specific factors, notably aggressive behavior.

Conclusions:  The findings illustrate how research using multilevel model designs and analytic strategies may enhance our understanding of family process.
Physical and emotional development, appetite and body image in adolescents who failed to thrive as infants
Authors: Drewett R.F. , Corbett S.S. , Wright C.M.
Published: April 2006

Background:  Previous studies suggest that failure to thrive in infancy may be associated with adverse sequelae in childhood. Although cognitive abilities have been extensively investigated, little systematic research is available on other aspects of development.

Methods:  Eighty‐nine children who failed to thrive as infants and 91 controls were followed up when twelve years old and examined using anthropometric measurement, self‐ratings of appetite and body image, the Dutch Eating Behaviour Questionnaire, the Self‐perception Profile for Children, The Revised Children's Manifest Anxiety Scale, the parent and child form of the Mood and Feelings Questionnaire and the parent and teacher's form of the Child Behavior Checklist.

Results:  The children who failed to thrive were significantly shorter and lighter at twelve and had significantly lower BMIs, but they did not go into puberty any later. They were more likely to rate their appetite as lower than their best friend's, were generally more satisfied with their body shape, and had significantly lower restraint score on the Dutch Eating Behaviour Questionnaire. They were not significantly different from controls on any of the measures reflecting anxiety, depression or low self‐esteem.

Conclusions:  Failure to thrive in infancy is not associated with adverse emotional development in childhood.
Letting the gene out of the bottle: the population genetics of genetically modified crops
Authors: Chapman Mark A. , Burke John M.
Published: April 2006

Genetically modified (GM) plants are rapidly becoming a common feature of modern agriculture. This transition to engineered crops has been driven by a variety of potential benefits, both economic and ecological. The increase in the use of GM crops has, however, been accompanied by growing concerns regarding their potential impact on the environment. Here, we focus on the escape of transgenes from cultivation via crop × wild hybridization. We begin by reviewing the literature on natural hybridization, with particular reference to gene flow between crop plants and their wild relatives. We further show that natural selection, and not the overall rate of gene flow, is the most important factor governing the spread of favorable alleles. Hence, much of this review focuses on the likely effects of transgenes once they escape. Finally, we consider strategies for transgene containment.

ContentsSummary429I.Introduction429II.How do transgenes escape? – Hybridization, gene flow, and introgression432III.Assessing selection on transgenes – costs and benefits434IV.The effects of transgenes – case studies435V.Can we prevent transgene escape?437VI.Conclusions and future directions440Acknowledgements440References440
Soil biota and invasive plants
Authors: Reinhart Kurt O. , Callaway Ragan M.
Published: April 2006

Interactions between plants and soil biota resist invasion by some nonnative plants and facilitate others. In this review, we organize research and ideas about the role of soil biota as drivers of invasion by nonnative plants and how soil biota may fit into hypotheses proposed for invasive success. For example, some invasive species benefit from being introduced into regions of the world where they encounter fewer soil‐borne enemies than in their native ranges. Other invasives encounter novel but strong soil mutualists which enhance their invasive success. Leaving below‐ground natural enemies behind or encountering strong mutualists can enhance invasions, but indigenous enemies in soils or the absence of key soil mutualists can help native communities resist invasions. Furthermore, inhibitory and beneficial effects of soil biota on plants can accelerate or decelerate over time depending on the net effect of accumulating pathogenic and mutualistic soil organisms. These ‘feedback’ relationships may alter plant–soil biota interactions in ways that may facilitate invasion and inhibit re‐establishment by native species. Although soil biota affect nonnative plant invasions in many different ways, research on the topic is broadening our understanding of why invasive plants can be so astoundingly successful and expanding our perspectives on the drivers of natural community organization.

Contents

Summary
445

I
Introduction
446

II
Soil community effects
446

III
Soil‐borne antagonists
451

IV
Soil‐borne mutualists
452

V
Conclusion
454

Acknowledgements
454

References
454
Re‐evaluation of serum alanine aminotransferase upper normal limit and its modulating factors in a large‐scale population study
Authors: Kariv Revital , Leshno Moshe , Beth‐Or Anat , Strul Hana , Blendis Laurie , Kokia Ehud , Noff Dina , Zelber‐Sagie Shira , Sheinberg Bracha , Oren Ran , Halpern Zamir
Published: April 2006

Abstract: Background: The upper normal limit (ULN) of serum alanine‐aminotrasferase (ALT) normal range was recently challenged, because patients diagnosed with liver diseases may have ‘normal’ or near‐‘normal’ ALT levels, and because possible modulators are often ignored in determining normal range.

Aim: To estimate the ULN for serum ALT and to identify factors modulating it.

Subjects and methods: We reviewed medical records of subjects aged 15–90, who underwent standard panels of laboratory tests, including serum ALT, over 6 months at a central laboratory. Three groups were defined: Group 1, comprised total study population (N=272 273). Group 2 (N=87 020) comprised total study population, excluding those receiving potentially hepatotoxic drugs, or diagnosed with liver disease, or had any abnormal laboratory test results other than for triglycerides, cholesterol, glucose, or HbA1c. Group 3 (N=17 496) the ‘healthy’ population, from whose ALT values we established the new ULN, comprised Group 2 subjects with normal triglycerides, cholesterol, glucose, and HbA1c levels.

Results: The 95th percentile ALT values, corresponding to the ULN, in groups 1, 2, and 3 were 50.1, 40, and 37.5 U/l, respectively. 6.2% (16 943/273 273) of subjects whose ALT was below ULN listed by the test manufacturer (52 U/l), had ALT level above our new ULN. Linear and logistic‐regression analyses showed that ALT levels were significantly modified by gender, age, glucose, cholesterol, triglycerides, and overweight/obesity diagnosis. Significant interaction was found between gender, glucose and cholesterol levels.

Conclusions: In this first large‐scale study of ‘healthy’ population, serum ALT ULN was far lower than currently accepted value. Age and gender may be considered when determining the ULN for ALT.