Toxicity and Functional Tissue Responses of Two Freshwater Fish after Exposure to Polystyrene Microplastics.

Microplastics (MPs)' ingestion has been demonstrated in several aquatic organisms. This process may facilitate the hydrophobic waterborne pollutants or chemical additives transfer to biota. In the present study the suitability of a battery of biomarkers on oxidative stress, physiology, tissue function and metabolic profile was investigated for the early detection of adverse effects of 21-day exposure to polystyrene microplastics (PS-MPs, sized 5-12 µm) in the liver and gills of zebrafish Danio rerio and perch, Perca fluviatilis, both of which are freshwater fish species. An optical volume map representation of the zebrafish gill by Raman spectroscopy depicted 5 µm diameter PS-MP dispersed in the gill tissue. Concentrations of PS-MPs close to the EC50 of each fish affected fish physiology in all tissues studied. Increased levels of biomarkers of oxidative damage in exposed fish in relation to controls were observed, as well as activation of apoptosis and autophagy processes. Malondialdehyde (MDA), protein carbonyls and DNA damage responses differed with regard to the sensitivity of each tissue of each fish. In the toxicity cascade gills seemed to be more liable to respond to PS-MPs than liver for the majority of the parameters measured. DNA damage was the most susceptible biomarker exhibiting greater response in the liver of both species. The interaction between MPs and cellular components provoked metabolic alterations in the tissues studied, affecting mainly amino acids, nitrogen and energy metabolism. Toxicity was species and tissue specific, with specific biomarkers responding differently in gills and in liver. The fish species that seemed to be more susceptible to MPs at the conditions studied, was P. fluviatilis compared to D. rerio. The current findings add to a holistic approach for the identification of small sized PS-MPs' biological effects in fish, thus aiming to provide evidence regarding PS-MPs' environmental impact on wild fish populations and food safety and adequacy.

Job Crafting and Work Engagement: Can their Relationship be Explained by a Catastrophe Model?

To shed light on findings suggesting that not all job crafting strategies are (equally) favourable for employee motivation, we applied cusp catastrophe models to explore the possibility that combinations of job crafting strategies might be associated with nonlinear changes in work engagement (i.e., vigour, dedication, and absorption). We used cross-sectional data from a heterogeneous sample of 193 Greek employees and investigated increasing social and structural job resources as asymmetry factors, and increasingly challenging job demands and decreasingly hindering job demands as bifurcation factors in relation to work engagement. Cusp models, analysed with the maximum likelihood and least squares methods, proved superior to their linear alter-natives. Increasing social job resources functioned as the asymmetry factor for vigour and dedication. Increasing structural job resources was the asymmetry factor for absorption. The bifurcation factors were decreasing hindering job demands for vigour and increasing job challenges for dedication and absorption. This evidence suggests that threshold values exist in decreasing hindering and increasing challenging job demands, beyond which sudden changes in work engagement occur. The supported nonlinear models add in explaining when job crafting strategies are unfavourable for employees and have epistemological implications by suggesting that the underlying processes may be viewed as a complex dynamical system.

Social support moderates the impact of demands on burnout and organizational connectedness: a two-wave study of volunteer firefighters.

This two-wave study of volunteers examined the effect of family and friend support on the relationship between volunteer demands (emotional demands and work-home conflict) on the one hand, and burnout (exhaustion and cynicism) and organizational connectedness on the other hand. It was hypothesized that family and friend support would moderate the relationship between (a) demands at Time 1 (T1) and burnout at Time 2 (T2); and (b) demands at T1 and organizational connectedness at T2. Hypotheses were tested among 126 Australian volunteer firefighters, who were followed up over 1 year. Results showed that support moderated the relationship between work-home conflict and exhaustion, but not between emotional demands and exhaustion. In addition, family and friend support moderated the relationship between both volunteer demands at T1 and cynicism and organizational connectedness at T2. These results suggest that support from family and friends is a critical resource in coping with the demands related to volunteer work and may protect volunteers from burnout, while helping them to stay connected to volunteering. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Burnout and connectedness in the job demands-resources model: studying palliative care volunteers and their families.

This study examined the role of burnout and connectedness in the job demands-resources (JD-R) model among palliative care volunteers. It was hypothesized that (a) exhaustion mediates the relationship between demands and depression, and between demands and retention; (b) cynicism mediates the relationship between resources and retention; and (c) connectedness mediates the relationship between resources and retention. Hypotheses were tested in 2 separate analyses: structural equation modeling (SEM) and path analyses. The first was based on volunteer self-reports (N = 204), while the second analysis concerned matched data from volunteers and their family members (N = 99). While strong support was found for cynicism and connectedness as mediators in both types of analyses, this was not altogether the case for exhaustion. Implications of these findings for the JD-R model and volunteer organizations are discussed.

Cómo los empleados mantienen su engagement en el trabajo / How do engaged employees stay engaged?

El presente trabajo apunta a descubrir qué pueden hacer los empleados para estar más engaged con su trabajo. Después de definir qué se entiende por un engagement perdurable, hacemos una revisión de la bibliografía existente sobre el engagement entendido como un estado mental del individuo. Además, analizamos las diferentes investigaciones que se han dedicado a estudiar la relación que hay entre engagement, por un lado, y (a) desempeño laboral, (b) conducta proactiva y (c) personalización del trabajo, por el otro. Finalmente, revisamos la evidencia que sustenta las relaciones recíprocas entre el engagement, los recursos personales y laborales. Concluimos que los empleados engaged se encargan de mantener su propio compromiso en el trabajo, modificando proactivamente su ambiente laboral. Como resultado, los empleados engaged no sólo hacen un uso total de los recursos laborales disponibles, sino que también son capaces de crear sus propios recursos para mantenerse comprometidos.

The present literature review focuses on what employees can do to stay engaged. After defining enduring work engagement, we review the literature on state work engagement. In addition, we discuss research on the relationship between engagement on the one hand, and (a) job performance, (b) proactive behavior, and (c) job crafting on the other. Finally, we review the evidence for reciprocal relationships between work engagement and job and personal resources. We conclude that engaged employees take care of their own work engagement by proactively shaping their work environment. As a result, engaged employees do not only make full use of the available job resources, but they also create their own resources to stay engaged.

The crossover of daily work engagement: test of an actor-partner interdependence model.

This study of 62 dyads of employees (N = 124) examined the crossover of work engagement-a positive, fulfilling, work-related state of mind that is characterized by vigor, dedication, and absorption. We hypothesized that work engagement crosses over from an employee (the actor) to his or her colleague (the partner) on a daily basis. The frequency of daily communication was expected to moderate the crossover of daily work engagement, which in turn would relate to colleagues' daily performance. Participants first filled in a general questionnaire and then completed a diary study over 5 consecutive workdays. The hypotheses were tested with multilevel analyses, using an actor-partner interdependence model. Results confirmed the crossover of daily work engagement, but only on days when employees within a dyad interacted more frequently than usual. Moreover, we found that actor's work engagement (particularly vigor), when frequently communicated, had a positive indirect relationship with partner's performance through partner's work engagement. Finally, results showed that actor's vigor was negatively related to partner's performance when communication was low. However, this negative effect was counteracted when mediated by the vigor of the partner.

Working in the sky: a diary study on work engagement among flight attendants.

This study aims to gain insight in the motivational process of the Job Demands-Resources (JD-R) model by examining whether daily fluctuations in colleague support (i.e., a typical job resource) predict day-levels of job performance through self-efficacy and work engagement. Forty-four flight attendants filled in a questionnaire and a diary booklet before and after consecutive flights to three intercontinental destinations. Results of multilevel analyses revealed that colleague support had unique positive effects on self-efficacy and work engagement. Self-efficacy did not mediate the relationship between support and engagement, but work engagement mediated the relationship between self-efficacy and (in-role and extra-role) performance. In addition, colleague support had an indirect effect on in-role performance through work engagement. These findings shed light on the motivational process as outlined in the JD-R model, and suggest that colleague support is an important job resource for flight attendants helping them reach their work-related goals.