61 research outputs found
Minor differences in body condition and immune status between avian influenza virus-infected and noninfected mallards: a sign of coevolution?
Wildlife pathogens can alter host fitness. Low pathogenic avian influenza virus (LPAIV) infection is thought to have negligible impacts on wild birds; however, effects of infection in free-living birds are largely unstudied. We investigated the extent to which LPAIV infection and shedding were associated with body condition and immune status in free-living mallards (Anas platyrhynchos), a partially migratory key LPAIV host species. We sampled mallards throughout the species\u27 annual autumn LPAIV infection peak, and we classified individuals according to age, sex, and migratory strategy (based on stable hydrogen isotope analysis) when analyzing data on body mass and five indices of immune status. Body mass was similar for LPAIV-infected and noninfected birds. The degree of virus shedding from the cloaca and oropharynx was not associated with body mass. LPAIV infection and shedding were not associated with natural antibody (NAbs) and complement titers (first lines of defense against infections), concentrations of the acute phase protein haptoglobin (Hp), ratios of heterophils to lymphocytes (H:L ratio), and avian influenza virus (AIV)-specific antibody concentrations. NAbs titers were higher in LPAIV-infected males and local (i.e., short distance) migrants than in infected females and distant (i.e., long distance) migrants. Hp concentrations were higher in LPAIV-infected juveniles and females compared to infected adults and males. NAbs, complement, and Hp levels were lower in LPAIV-infected mallards in early autumn. Our study demonstrates weak associations between infection with and shedding of LPAIV and the body condition and immune status of free-living mallards. These results may support the role of mallards as asymptomatic carriers of LPAIV and raise questions about possible coevolution between virus and host
The roles of migratory and resident birds in local avian influenza infection dynamics
Migratory birds are an increasing focus of interest when it comes to infection dynamics and the spread of avian influenza viruses (AIV ). However, we lack detailed understanding of migratory birdsâ contribution to local AIV prevalence levels and their downstream socioâeconomic costs and threats.
To explain the potential differential roles of migratory and resident birds in local AIV infection dynamics, we used a susceptibleâinfectiousârecovered (SIR ) model. We investigated five (mutually nonâ exclusive) mechanisms potentially driving observed prevalence patterns: (1) a pronounced birth pulse (e.g. the synchronised annual influx of immunologically naĂŻve individuals), (2) shortâterm immunity, (3) increase in susceptible migrants, (4) differential susceptibility to infection (i.e. transmission rate) for migrants and residents, and (5) replacement of migrants during peak migration.
SIR models describing all possible combinations of the five mechanisms were fitted to individual AIV infection data from a detailed longitudinal surveillance study in the partially migratory mallard duck (Anas platyrhynchos ). During autumn and winter, the local resident mallard community also held migratory mallards that exhibited distinct AIV infection dynamics.
Replacement of migratory birds during peak migration in autumn was found to be the most important mechanism driving the variation in local AIV infection patterns. This suggests that a constant influx of migratory birds, likely immunological naĂŻve to locally circulating AIV strains, is required to predict the observed temporal prevalence patterns and the distinct differences in prevalence between residents and migrants.
Synthesis and applications . Our analysis reveals a key mechanism that could explain the amplifying role of migratory birds in local avian influenza virus infection dynamics; the constant flow and replacement of migratory birds during peak migration. Apart from monitoring efforts, in order to achieve adequate disease management and control in wildlifeâwith knockâon effects for livestock and humans,âwe conclude that it is crucial, in future surveillance studies, to record host demographical parameters such as population density, timing of birth and turnover of migrants
Professionalism, Golf Coaching and a Master of Science Degree: A commentary
As a point of reference I congratulate Simon Jenkins on tackling the issue of professionalism in coaching. As he points out coaching is not a profession, but this does not mean that coaching would not benefit from going through a professionalization process. As things stand I find that the stimulus article unpacks some critically important issues of professionalism, broadly within the context of golf coaching. However, I am not sure enough is made of understanding what professional (golf) coaching actually is nor how the development of a professional golf coach can be facilitated by a Master of Science Degree (M.Sc.). I will focus my commentary on these two issues
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Understanding the factors that determine workplace coaching effectiveness: a systematic literature review
Meta-analytic results have established that workplace coaching is effective, however, little is known about the determinants of coaching effectiveness. This paper reports an inclusive systematic literature review, covering the quantitative and qualitative research on workplace coaching. We focus on seven promising areas in the current workplace coaching literature that emerged by the synthesis of 117 empirical studies: self-efficacy, coaching motivation, goal orientation, trust, interpersonal attraction, feedback intervention, and supervisory support. The major contribution of our paper is the systematic integration of well-established theoretical constructs in the workplace coaching context and the new insights we provide in the synthesis of these literatures. Based on our review we provide specific recommendations to be addressed in future research, including recommended research methodologies, which we propose will significantly progress the field of workplace coaching theory and practice
Defining the industrial and engineering management professional profile: a longitudinal study based on job advertisements
The engineering professional profiles have been discussed by several branches of the engineering field. On the one hand, this discussion helps to understand the professional practice and contributes to the specification of the competences that are suitable for each function and company culture. On the other hand, it is an essential starting point for the definition of curricula in engineering schools. Thus, this study aims to characterize, in an innovative way based on job advertisements, the demand for competences and areas of practice for Industrial Engineering and Management contributing for the definition of a professional profile. This characterization is based on the analysis of 1391 job advertisements, collected during seven years from a Portuguese newspaper. The data analysis takes into account the job description in which two categories were considered: areas of professional practice (e.g. project management) and transversal competences (e.g. teamwork). Considering the total number of job advertisements, it was possible to identify 1,962 cumulative references for 11 professional practice areas and 5,261 cumulative references for transversal competences. The contribution of this study lies on the identification of the main areas of practice and the main transversal competences demanded by employers.This work was partially funded by COMPETE-POCI-01-0145-FEDER-007043 and FCT-UID-CEC-00319-2013
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