Rapid depletion of genotypes with fast growth and bold personality traits from harvested fish populations

The possibility for fishery-induced evolution of life history traits is an important but unresolved issue for exploited fish populations. Because fisheries tend to select and remove the largest individuals, there is the evolutionary potential for lasting effects on fish production and productivity. Size selection represents an indirect mechanism of selection against rapid growth rate, because individual fish may be large because of rapid growth or because of slow growth but old age. The possibility for direct selection on growth rate, whereby fast-growing genotypes are more vulnerable to fishing irrespective of their size, is unexplored. In this scenario, faster-growing genotypes may be more vulnerable to fishing because of greater appetite and correspondingly greater feeding-related activity rates and boldness that could increase encounter with fishing gear and vulnerability to it. In a realistic whole-lake experiment, we show that fast-growing fish genotypes are harvested at three times the rate of the slow-growing genotypes within two replicate lake populations. Overall, 50% of fast-growing individuals were harvested compared with 30% of slow-growing individuals, independent of body size. Greater harvest of fast-growing genotypes was attributable to their greater behavioral vulnerability, being more active and bold. Given that growth is heritable in fishes, we speculate that evolution of slower growth rates attributable to behavioral vulnerability may be widespread in harvested fish populations. Our results indicate that commonly used minimum size-limits will not prevent overexploitation of fast-growing genotypes and individuals because of size-independent growth-rate selection by fishing.

Small within-day increases in temperature affects boldness and alters personality in coral reef fish

Consistent individual differences in behaviour, termed personality, are common in animal populations and can constrain their responses to ecological and environmental variation, such as temperature. Here, we show for the first time that normal within-daytime fluctuations in temperature of less than 3°C have large effects on personality for two species of juvenile coral reef fish in both observational and manipulative experiments. On average, individual scores on three personality traits (PTs), activity, boldness and aggressiveness, increased from 2.5- to sixfold as a function of temperature. However, whereas most individuals became more active, aggressive and bold across temperature contexts (were plastic), others did not; this changed the individual rank order across temperatures and thus altered personality. In addition, correlations between PTs were consistent across temperature contexts, e.g. fish that were active at a given temperature also tended to be both bold and aggressive. These results (i) highlight the importance of very carefully controlling for temperature when studying behavioural variation among and within individuals and (ii) suggest that individual differences in energy metabolism may contribute to animal personality, given that temperature has large direct effects on metabolic rates in ectotherms.

Are animal personality traits linked to life-history productivity?

Animal personality traits such as boldness, activity and aggressiveness have been described for many animal species. However, why some individuals are consistently bolder or more active than others, for example, is currently obscure. Given that life-history tradeoffs are common and known to promote inter-individual differences in behavior, we suggest that consistent individual differences in animal personality traits can be favored when those traits contribute to consistent individual differences in productivity (growth and/or fecundity). A survey of empirical studies indicates that boldness, activity and/or aggressiveness are positively related to food intake rates, productivity and other life-history traits in a wide range of taxa. Our conceptual framework sets the stage for a closer look at relationships between personality traits and life-history traits in animals.

Clarifying the effort-reward imbalance model : the role of personality

The thesis aimed to identify the sources of stress experienced by a sample of Australian police officers. It was guided by the Effort-Reward Imbalance model, augmented with Type A personality components. The findings support the research model and suggest that interventions to reduce stress should focus on reward and recognition.

Comparing the small sample properties of two break Lagrange Multiplier unit root tests

In this note, we examine the size and power properties and the break date estimation accuracy of the Lee and Strazicich (LS, 2003) two break endogenous unit root test, based on two different break date selection methods: minimising the test statistic and minimising the sum of squared residuals (SSR). Our results show that the performance of both Models A and C of the LS test are superior when one uses the minimising SSR procedure.

The mediating role of work climate perceptions in the relationship between personality and performance

Although past research has demonstrated a link between personality and job performance, potential enabling factors of this relationship have yet to be explored comprehensively. We hypothesized that perceptions of work climate, specifically relationship dimensions—cohesion, supervisor support, and job involvement—might be the mechanism through which the relationship between personality and job performance can be explained. Two hundred and thirty Australian employees completed an online survey measuring personality, relationship dimensions of work climate (job involvement, coworker cohesion, and supervisor support) and job performance. Results revealed that the relationship dimensions of work climate fully mediated the relationship between agreeableness and job performance, and extraversion and job performance, while the relationship between neuroticism and job performance was partially mediated by relationship dimensions of work climate. Supervisor support primarily accounted for this mediated effect for the neuroticism–job performance relationship, whereas for extraversion only job involvement explained significant unique variance. Our findings suggest that the relationship of agreeableness, extraversion, and neuroticism with job performance is indirect, and perceptions of the work environment itself play a role in this relationship. This implies that organizations should consider the work environment, in addition to personality during selection procedures. Future research should examine whether different levels of work environment dimensions, foster greater job performance in employees.

Static and dynamic tests for damage identification of a slab-girder structure

Slab-girder bridges are widely used in Australia. The shear connection between reinforced concrete slab and steel girder plays an important role in composite action. In order to test the suitability and efficiency of various vibration-based damage identification methods to assess the integrity of the structure, a scaled composite bridge model was constructed in the laboratory. Some removable shear connectors were specially designed and fabricated to link the beam and slab that were cast separately. In this test, two static loads were acted in the 1/3 points of the structure. In the first stage, dynamic test was conducted under different damage scenarios, where a number of shear connectors were removed step by step. In the second stage, the static load is increased gradually until concrete slab cracked. Static tests were conducted continuously to monitor the deflection and loading on the beam. Dynamic test was carried out before and after concrete cracking. Both static and dynamic results can be used to identify damage in the structure.

Managing borderline personality disorder and substance use : an integrated approach

Background : Although substance use is a common feature of borderline personality disorder, regular use is associated with greater levels of psychosocial impairment, psychopathology, self harm and suicidal behaviour and leads to poorer treatment outcomes. Management of co-occurring substance use disorder and borderline personality disorder within primary care is further compounded by negative attitudes and practices in responding to people with these conditions, which can lead to a fractured patient-doctor relationship.

Objective : This article provides an overview of how the general practitioner can provide effective support for patients with co-occurring borderline personality disorder and substance use disorder, including approaches to assessment and treatment, the therapeutic relationship, referral pathways and managing risk and chronic suicidality.

Discussion : Despite the complexities associated with this population, GPs are ideally placed to engage patients with co-occurring borderline personality disorder and substance use disorder in a long term therapeutic relationship, while also ensuring timely referral to other key services and health professionals. To provide the most effective responses to this patient group, GPs need to understand borderline personality disorder and its relationship to substance use, develop an ‘explanatory framework’ for challenging behaviours, implement mechanisms for reflective practice to manage negative countertransference, as well as learn skills to respond adequately to behaviours which jeopardise treatment retention.

Religious/spiritual well-being, coping styles and personality dimensions in people with substance use disorders

Religiosity and spirituality have been found to be negatively associated with a range of addictions. It has been suggested that religious/spiritual well-being might play an important role in the development, course and the recovery from addictive disorders. A sample of addiction in-patients (n=389) was assessed using the Multidimensional Inventory for Religious/Spiritual Well-Being (MI-RSWB) and compared with a matched group of non-addicted community controls (n=389). RSWB was found to be substantially lower in people with substance use disorders compared to the normal sample. Discriminate functional analysis showed that Experiences of Sense and Meaning, General Religiosity and Forgiveness were the dimensions of RSWB which strongly distinguished the groups. Within the group of people with substance use disorders, RSWB was strongly positively associated with the personality dimensions of Conscientiousness, Agreeableness and Openness as well as Sense of Coherence and positive Coping styles. The study suggests that therapeutic intervention programs focusing on building a positive and meaningful personal framework, akin to that of a religious/spiritual orientation, may contribute to positive outcomes in addiction treatment.