Estimation for the general sample selection models

Consider a general regression model with an arbitrary and unknown link function and a stochastic selection variable that determines whether the outcome variable is observable or missing. The paper proposes U-statistics that are based on kernel functions as estimators for the directions of the parameter vectors in the link function and the selection equation, and shows that these estimators are consistent and asymptotically normal.

Criteria for working-correlation-structure selection in GEE: Assessment via simulation

Efficiency of analysis using generalized estimation equations is enhanced when intracluster correlation structure is accurately modeled. We compare two existing criteria (a quasi-likelihood information criterion, and the Rotnitzky-Jewell criterion) to identify the true correlation structure via simulations with Gaussian or binomial response, covariates varying at cluster or observation level, and exchangeable or AR(l) intracluster correlation structure. Rotnitzky and Jewell's approach performs better when the true intracluster correlation structure is exchangeable, while the quasi-likelihood criteria performs better for an AR(l) structure.

On the moulding of population viscosity by natural selection

In this paper, we explore the conjoint evolution of dispersal and social behaviour. The model investigated is of a population distributed over a number of sites each with a carrying capacity of two adults and an episode of dispersal in the juvenile stage. The fertilities are governed by whether an individual and its neighbour are selfish or co-operative. It is shown that the best dispersal strategy for the co-operative genotype always involves lower levels of dispersal; and further that ecological conditions favouring low levels of dispersal increase the selective advantage of a co-operative genotype. Given this positive feedback, we suggest that in any taxon viscosity and co-operativity will tend to be correlated and bimodally distributed. Hence we predict the existence of two kinds of animal societies; viscous and co-operative (e.g. quasi-social wasps such as Mischocyttarus), and non-viscous and selfish (e.g. communal sphecid wasps such as Cerceris), and relatively few social groups with intermediate levels of co-operativity and viscosity. We also suggest that when one of the two sexes disperses, it will be the sex with lower potential for co-operative behaviour.

Genetic response to growth rate selection in pigs measured on two feeding levels

From the findings of McPhee et al. (1988), there is an expectation that selection in the growing pig for bodyweight gain measured on restricted feeding will result in favourable responses in the rate and efficiency of growth of lean pork on different levels of feeding. This paper examines this in two lines of Australian Large White pigs which have undergone 3 years of selection for high and for low growth rate over a 6-week period starting at 50 kg liveweight. Over this test period, pigs of both lines are all fed the same total amount of grower food, restricted to an estimated 80% of average ad libitum intake. 'Animal production for a consuming world': proceedings of 9th Congress of the AAAAP Societies and 23rd Biennial Conference of the ASAP and 17th Annual Symposium of the University of Sydney, Dairy Research Foundation, (DRF). Sydney, Australia.

Selection and characterisation of two attenuated vaccine lines of Eimeria tenella in Australia

Objective To attenuate two strains of Eimeria tenella by selecting for precocious development and evaluate the strains in characterisation trials and by field evaluation, to choose one precocious line for incorporation into an Australian live coccidiosis vaccine for poultry. Design Two strains from non-commercial flocks were passaged through chickens while selecting for precocious development. Each strain was characterised for drug sensitivity, pathogenicity, protection against homologous and heterologous challenge, and oocyst output in replicated experiments in which the experimental unit was a cage of three birds. Oocyst output and/or body weight gain data collected over a 10 to 12 day period following final inoculation were measured. Feed conversion ratios were also calculated where possible. Results Fifteen passages resulted in prepatent periods reduced by 24 h for the Redlands strain (from 144 h to 120 h)and 23 h for the Darryl strain (from 139 h to 116 h). Characterisation trials demonstrated that each precocious line was significantly less pathogenic than its parent strain and each effectively induced immunity that protected chickens against challenge with both the parent strain and other virulent field strains. Both lines had oocyst outputs that, although significantly reduced relative to the parent strains, remained sufficiently high for commercial vaccine production, and both showed susceptibility to coccidiostats. Conclusion Two attenuated lines have been produced that exhibit the appropriate characteristics for use in an Australian live coccidiosis vaccine.

International Society for Applied Ethology. Special issue: a Selection of Papers from the 38th International Congress of the ISAE, Helsinki, Finland, August 2004

Welcome to the latest collection of papers selected from the International Society for Applied Ethology's (ISAE's) annual congress. The ISAE is a multi-faceted scientific society that supports applied research on animals under the influence of humankind. Every year, we aim to invite congress participants who have submitted papers, plenary talks, run workshops, or presented the memorial lecture on theoretical, review or discussion papers of topical interest to contribute to the Special Issue. These papers are peer-reviewed before being published here in Applied Animal Behaviour Science. International Society for Applied Ethology (ISAE) Special Issue 2004.

International Society for Applied Ethology. Special issue: a selection of papers from the 39th International Congress of the International Society for Applied Ethology (ISAE), Tokyo, Japan, August 2005

Welcome to the latest collection of papers selected from the International Society for Applied Ethology's (ISAE's) annual congress. The ISAE is a multi-faceted scientific society that supports applied research on animals that are managed by humans. Every year, we aim to invite congress participants who have submitted papers, plenary talks, run workshops, or presented the memorial lecture on theoretical, review or discussion papers of topical interest to contribute to the Special Issue. These papers are peer-reviewed before being published here in Applied Animal Behaviour Science. This year, we have a variety of papers to bring to your attention. The David Wood-Gush Memorial lecture, the keynote address of the congress, was given by Shigeru Watanabe on animal cognition and welfare. His paper highlights how animal's sensory capabilities relate to their welfare. On the topic of human–animal bonds, Stine Christiansen and Björn Forkman explore how animal welfare is assessed in a veterinary context, and how those assessments might be improved by ethologists. Yoshie Kakuma and co-authors report on the discussions from a workshop on the welfare of working and companion dogs in five different countries. Based on their plenary lectures, Michael Cockram discusses the factors that affect farmed animals during road transport and how these might contribute in making decisions to restrict journey times, while Clive Phillips and co-author Danica Peck examine how personality influences the behaviour and interactions between zoo-housed tigers and their keepers. We hope you enjoy these papers. Our sincere thanks go to both the authors and referees, without whom these special issues would not be possible. A selection of papers from the 39th International Congress of the International Society for Applied Ethology (ISAE), Tokyo, Japan, August 2005.

Genetic analysis of foot-and-mouth disease virus serotype A of Indian origin and detection of positive selection and recombination in leader protease- and capsid-coding regions

The leader protease (L-pro) and capsid-coding sequences (P1) constitute approximately 3 kb of the foot-and-mouth disease virus (FMDV). We studied the phylogenetic relationship of 46 FMDV serotype A isolates of Indian origin collected during the period 1968-2005 and also eight vaccine strains using the neighbour-joining tree and Bayesian tree methods. The viruses were categorized under three major groups - Asian, Euro-South American and European. The Indian isolates formed a distinct genetic group among the Asian isolates. The Indian isolates were further classified into different genetic subgroups (<5% divergence). Post-1995 isolates were divided into two subgroups while a few isolates which originated in the year 2005 from Andhra Pradesh formed a separate group. These isolates were closely related to the isolates of the 1970s. The FMDV isolates seem to undergo reverse mutation or onvergent evolution wherein sequences identical to the ancestors are present in the isolates in circulation. The eight vaccine strains included in the study were not related to each other and belonged to different genetic groups. Recombination was detected in the L-pro region in one isolate (A IND 20/82) and in the VP1 coding 1D region in another isolate (A RAJ 21/96). Positive selection was identified at aa positions 23 in the L-pro (P<0.05; 0.046*) and at aa 171 in the capsid protein VP1 (P<0.01; 0.003**).

The accuracy of varietal selection using factor analytic models for multi-environment plant breeding trials

Modeling of cultivar x trial effects for multienvironment trials (METs) within a mixed model framework is now common practice in many plant breeding programs. The factor analytic (FA) model is a parsimonious form used to approximate the fully unstructured form of the genetic variance-covariance matrix in the model for MET data. In this study, we demonstrate that the FA model is generally the model of best fit across a range of data sets taken from early generation trials in a breeding program. In addition, we demonstrate the superiority of the FA model in achieving the most common aim of METs, namely the selection of superior genotypes. Selection is achieved using best linear unbiased predictions (BLUPs) of cultivar effects at each environment, considered either individually or as a weighted average across environments. In practice, empirical BLUPs (E-BLUPs) of cultivar effects must be used instead of BLUPs since variance parameters in the model must be estimated rather than assumed known. While the optimal properties of minimum mean squared error of prediction (MSEP) and maximum correlation between true and predicted effects possessed by BLUPs do not hold for E-BLUPs, a simulation study shows that E-BLUPs perform well in terms of MSEP.

Simple sequence repeat markers associated with three quantitative trait loci for black point resistance can be used to enrich selection populations in bread wheat

Black point in wheat has the potential to cost the Australian industry $A30.4 million a year. It is difficult and expensive to screen for resistance, so the aim of this study was to validate 3 previously identified quantitative trait loci (QTLs) for black point resistance on chromosomes 2B, 4A, and 3D of the wheat variety Sunco. Black point resistance data and simple sequence repeat (SSR) markers, linked to the resistance QTLs and suited to high-throughput assay, were analysed in the doubled haploid population, Batavia (susceptible) × Pelsart (resistant). Sunco and Pelsart both have Cook in their pedigree and both have the Triticum timopheevii translocation on 2B. SSR markers identified for the 3 genetic regions were gwm319 (2B, T. timopheevii translocation), wmc048 (4AS), and gwm341 (3DS). Gwm319 and wmc048 were associated with black point resistance in the validation population. Gwm341 may have an epistatic influence on the trait because when resistance alleles were present at both gwm319 and wmc048, the Batavia-derived allele at gwm341 was associated with a higher proportion of resistant lines. Data are presented showing the level of enrichment achieved for black point resistance, using 1, 2, or 3 of these molecular markers, and the number of associated discarded resistant lines. The level of population enrichment was found to be 1.83-fold with 6 of 17 resistant lines discarded when gwm319 and wmc048 were both used for selection. Interactions among the 3 QTLs appear complex and other genetic and epigenetic factors influence susceptibility to black point. Polymorphism was assessed for these markers within potential breeding material. This indicated that alternative markers to wmc048 may be required for some parental combinations. Based on these results, marker-assisted selection for the major black point resistance QTLs can increase the rate of genetic gain by improving the selection efficiency and may facilitate stacking of black point resistances from different sources.

Hiljainen tieto henkilöstön valinnassa : tutkimus työhaastatteluiden arvioinnissa hyödynnettävän tiedon hiljaisesta ulottuvuudesta

This study examined the fundamental question of what really matters when selecting a new employee. The study focused on tacit knowledge used by personnel recruiters when interviewing employees. Knowledge was defined as the best view available, which helps one not to act haphazardly. Tacit knowledge was also defined as a positive concept, and it was seen as a part of personnel recruiters` improving proficiency. The research topic was chosen based on the observed increase in the amount of employment interviews and their importance in society. As recruiting is becoming a more distinct profession, it was reasonable to approach the topic from an educational point of view. The following research problems guided the examination of the phenomenon: 1) Where does the interviewer seek tacit knowledge from during the employment interview? 2) How is tacit knowledge achieved during the employment interview? 3) How does the interviewer defend the significance of the tacit knowledge gained as knowledge that has influence on the selection decision? The research data was collected by interviewing six personnel recruiters who conduct and evaluate employment interviews as part of their work responsibilities. The interview themes were linked to some recently made selection decision in each organization and the preceding employment interview with the selected candidate. In order to conceptualize tacit knowledge, reflective consideration of the interview event was used in the study. The lettered research data was analyzed inductively. As a result of the study, the objects of tacit knowledge in the context of an employment interview culminated into three areas: the applicant s verbal communication, the applicant s non-verbal communication and the interaction between interview participants. Observations directed toward those objects were shown to be intentional and three schemes were found behind them: experiences from previous interviews, applicant s application papers and the aptitude for the work responsibilities. The question of gaining knowledge was answered with the concept of procedural knowledge. Personnel recruiters were found to have four different, but interconnected ways to encounter knowledge during an employment interview: understanding, evaluative, revealing, and approving knowing. In order to explain the importance given to tacit knowledge, it was examined in connection with the most prevalent practices in the personnel selection industry. The significance of knowledge as the kind of knowledge that has an impact on the decision was supported by references to collective opinion (other people agree with it), circumstance (interview s short duration), or using some instrument (structured interview). The study revealed new aspects of employment selection process through examining tacit knowledge. The characteristics of the inductive analysis of the research data may also be utilized, when applicable, in tacit knowledge research within other contexts.

Improving the agent selection, release and evaluation process: the role of bioclimatic modelling

The value of CLIMEX models to inform biocontrol programs was assessed, including predicting the potential distribution of biocontrol agents and their subsequent population dynamics, using bioclimatic models for the weed Parkinsonia aculeata, two Lantana camara biocontrol agents, and five Mimosa pigra biocontrol agents. The results showed the contribution of data types to CLIMEX models and the capacity of these models to inform and improve the selection, release and post release evaluation of biocontrol agents. Foremost among these was the quality of spatial and temporal information as well as the extent to which overseas range data samples the species’ climatic envelope. Post hoc evaluation and refinement of these models requires improved long-term monitoring of introduced agents and their dynamics at well selected study sites. The authors described the findings of these case studies, highlighted their implications, and considered how to incorporate models effectively into biocontrol programs.

A scientific approach to agent selection

The prioritisation of potential agents on the basis of likely efficacy is an important step in biological control because it can increase the probability of a successful biocontrol program, and reduce risks and costs. In this introductory paper we define success in biological control, review how agent selection has been approached historically, and outline the approach to agent selection that underpins the structure of this special issue on agent selection. Developing criteria by which to judge the success of a biocontrol agent (or program) provides the basis for agent selection decisions. Criteria will depend on the weed, on the ecological and management context in which that weed occurs, and on the negative impacts that biocontrol is seeking to redress. Predicting which potential agents are most likely to be successful poses enormous scientific challenges. 'Rules of thumb', 'scoring systems' and various conceptual and quantitative modelling approaches have been proposed to aid agent selection. However, most attempts have met with limited success due to the diversity and complexity of the systems in question. This special issue presents a series of papers that deconstruct the question of agent choice with the aim of progressively improving the success rate of biological control. Specifically they ask: (i) what potential agents are available and what should we know about them? (ii) what type, timing and degree of damage is required to achieve success? and (iii) which potential agent will reach the necessary density, at the right time, to exert the required damage in the target environment?