Negative Effects Of High Levels Research Articles

Oxidative response to accumulation of trace metals in tissue of two bivalves, the Asian green mussel Perna viridis and the blood cockle Tegillarca granosa, living in Pattani Bay, Thailand.

Using bivalves to indicate aquatic pollutants was favorable for discerning the negative effects of high levels of metal accumulation in tissue. We investigated the correlation between trace metal accumulation and the tissue oxidative response of two bivalves. The Asian green mussel Perna viridis and the blood cockle Tegillarca granosa were sampled along with seawater and sediments from three locations around Pattani Bay, Thailand. Accumulation of nine trace metals (cadmium, cobalt, copper, chromium, nickel, manganese, iron, zinc, and lead) in seawater, sediments, and tissue and the oxidative tissue response were evaluated. Metal bioaccumulation factor, biota-sediment accumulation factor, and histopathology were also indicated. The present study found that P. viridis and T. granosa were macroconcentrators and bioaccumulative of cadmium, and their tissue accumulation of cadmium was strongly related to lipid peroxidation activation. Perna viridis exhibited a higher oxidative response than T. granosa, as indicated by malondialdehyde, catalase, and reduced glutathione levels. The present study indicated that P. viridis and T. granosa were macroconcentrators and bioaccumulative of cadmium, and their tissue accumulation of cadmium was strongly related to lipid peroxidation activation. Research has shown discernible negative effects of a high level of metal accumulation in tissue, and deformed and damaged tissues were present in the gills, digestive glands, intestines, and feet of P. viridis and T. granosa.

Cultural Values and Internet Banking in Europe. The Moderating Effect of Gender

This study analyses how national culture influences the use of Internet banking (IB) in Europe while considering the moderating effect of gender. Using Hofstede’s cultural model, we posit six hypotheses and we predict a different relationship between cultural values and IB in men and women. A sample of 19,255 individuals residing in 27 European Union countries was used. The results demonstrate that the cultural values of European countries can explain the use of IB. Specifically, the results highlight that the greatest use of IB is found in countries that have an individualistic culture and low levels of masculinity, along with varying levels of intensity between men and women. Regarding indulgence, it exerts a positive influence on IB, but only for men. Conversely, high scores for uncertainty avoidance reduce IB usage for women. Furthermore, using protective measures partially offsets the negative effect of high levels of uncertainty avoidance, but only for women.

Unlocking the link between user participation and new product performance: The moderating effect of network capability

User participation is regarded as an essential approach by firms seeking new product advantages. However, in the social media context, does more user participation improve new product development? This study explores the nonlinear effects of user participation on new product performance in the social media context, its inner mechanisms, and boundary conditions. The results show that there is an inverted U-shaped relationship between user participation and new product performance. Further, user participation exerts an inverted U-shaped relationship with knowledge creation, which positively affects new product performance. Moreover, when firms have high-level rather than low-level network capability, knowledge creation plays a significant mediating role. Additionally, network capability positively moderates the nonlinear relationship between user participation and knowledge creation. Specifically, increasing network capability increases the positive effect of low levels of user participation and reduces the negative effect of high levels of user participation.

Dose response to postruminal urea in lactating dairy cattle

Inclusion of urea in dairy cattle diets is often limited by negative effects of high levels of feed urea on dry matter intake (DMI) and efficiency of rumen N utilization. We hypothesized that supplying urea postruminally would mitigate these limitations and allow greater inclusion of urea in dairy cattle diets. Four rumen-fistulated Holstein-Friesian dairy cows (7 ± 2.1 lactations, 110 ± 30.8 d in milk; mean ± standard deviation) were randomly assigned to a 4 × 4 Latin square design to examine DMI, milk production and composition, digestibility, rumen fermentation, N balance, and plasma constituents in response to 4 levels of urea continuously infused into the abomasum (0, 163, 325, and 488 g/d). Urea doses were targeted to linearly increase the crude protein (CP) content of total DMI (diet plus infusion) by 0%, 2%, 4%, and 6% and equated to 0%, 0.7%, 1.4%, and 2.1% of expected DMI, respectively. Each 28-d infusion period consisted of a 7-d dose step-up period, 14 d of adaptation, and a 7-d measurement period. The diet was fed ad libitum as a total mixed ration [10.9% CP, 42.5% corn silage, 3.5% grass hay, 3.5% wheat straw, and 50.5% concentrate (dry matter basis)] and was formulated to meet 100%, 82%, and 53% of net energy, metabolizable protein, and rumen-degradable protein requirements, respectively. Linear, quadratic, and cubic effects of urea dose were assessed using polynomial regression assuming the fixed effect of treatment and random effects of period and cow. Dry matter intake and energy-corrected milk yield responded quadratically to urea dose, and milk urea content increased linearly with increasing urea dose. Apparent total-tract digestibility of CP increased linearly with increasing urea dose and ruminal NH3-N concentration responded quadratically to urea dose. Mean total VFA concentration was not affected by urea dose. The proportion of N intake excreted in feces decreased linearly and that excreted in urine increased linearly in response to increasing urea dose. The proportion of N intake excreted in milk increased linearly with increasing urea dose. Urinary urea excretion increased linearly with increasing urea dose. Microbial N flow responded cubically to urea dose, but the efficiency of microbial protein synthesis was not affected. Plasma urea concentration increased linearly with increasing urea dose. Regression analysis estimated that when supplemented on top of a low-CP diet, 179 g/d of postruminal urea would maximize DMI at 23.4 kg/d, corresponding to a dietary urea inclusion level of 0.8% of DMI, which is in line with the current recommendations for urea inclusion in dairy cattle diets. Overall, these results indicate that postruminal delivery of urea does not mitigate DMI depression as urea dose increases.

The limits of psychological safety: Nonlinear relationships with performance

While psychological safety climate is widely seen as having a positive relationship with work performance, there are compelling reasons as to why that may not always apply. We draw on cognitive psychology literature to suggest that high levels of psychological safety climate can actually harm the performance of routine tasks. The negative effect of high levels of psychological safety climate on these tasks can be moderated, however, by collective accountability. We find evidence for these propositions across five independent studies at different levels of analysis and organizational settings. We find that while moderate levels of psychological safety climate are associated with better in-role performance, high levels are associated with decreasing in-role performance. Collective accountability can buffer that decreasing performance. These results help identify the boundary conditions of psychological safety climate and extend research on it to organization-level and business outcomes with real-world consequences.

Prevalence of refractive errors in population aged 50 years and over: The Gilan eye study.

To describe the prevalence of refractive error (RE) and its association with other environmental and health factors among population aged ≥50 years who lived in Gilan, Iran in 2014. In this population-based cross-sectional study, 3281 individuals aged ≥50 years living in Gilan for at least 6 months were enrolled. The prevalence of different types of REs including myopia (spherical equivalent (SE)≤-0.50D), high myopia (SE ≤ -6.00D), hyperopia (SE≥ + 0.50D), high hyperopia (SE≥ + 3.00D), astigmatism (cylinder < -0.50D) and high astigmatism (cylinder < -2.25D) were determined. Anisometropia was defined as the SE difference of ≥1.00D between the two eyes. Associated factors including age, body mass index (BMI) and education were also studied. 2587 eligible individuals (58% female subjects) with the mean age of 62.6 ± 8.8 years participated (87.6% response rate). The prevalence of myopia, hyperopia and astigmatism was 19.2%, 48.6% and 57.4%, respectively. 3.6% high hyperopia, 0.5% high myopia and 4.5% high astigmatism were identified. The positive simultaneous effects3 of older age (Odds Ratio (OR) = 3.14), nuclear (OR = 1.71) and posterior subcapsular (OR = 1.61) cataracts as well as the negative effects of higher levels of education (OR = 0.28) were obtained on myopia. Higher BMI was found as a risk factor for hyperopia (OR = 1.67), while older patients were less likely to be hyperopic (OR = 0.31). Higher incidence of myopia and astigmatism was found in patients aged over 70 years. It was also found that patients at older ages who suffered with cataracts were at a higher risk of myopia, while elderly people with greater BMI were at a higher risk of hyperopia.

Non-Esterified Fatty Acid-Induced Apoptosis in Bovine Granulosa Cells via ROS-Activated PI3K/AKT/FoxO1 Pathway

Non-esterified fatty acid (NEFA), one of negative energy balance (NEB)'s most well-known products, has a significant impact on cows' reproductive potential. Our study used an in vitro model to investigate the deleterious effects of NEFA on bovine granulosa cells (BGCs) and its underlying molecular mechanism. The results showed that high levels of NEFA led to the accumulation of reactive oxygen species (ROS), increased the expression of apoptosis-related factors such as Bcl2-Associated X/B-cell lymphoma-2 (Bax/Bcl-2) and Caspase-3, and down-regulated steroid synthesis-related genes such as sterol regulatory element binding protein 1 (SREBP-1), cytochrome P450c17 (CYP17), and cytochrome P450 aromatase (CYP19), to promote oxidative stress, cell apoptosis, and steroid hormone synthesis disorders in BGCs. In addition, NEFA significantly inhibited phosphatidylinositol 3-kinase (PI3K) and phosphorylated protein kinase B (p-AKT) activity and increased forkhead box O1 (FoxO1) expression. To further explore the role of the PI3K/AKT/FoxO1 signaling pathway in NEFA, we found that pretreatment with AKT-specific activator SC79 (5 mg/mL) for 2 h or transfection with FoxO1 knockdown siRNA in BGCs could alleviate the negative effects of NEFA treatment by decreasing Bax/Bcl-2 ratio and Caspase-3 expression, and upregulating SREBP-1, CYP17, and CYP19 expression. Meanwhile, SC79 significantly inhibited NEFA-induced dephosphorylation and massive nuclear translocation of FoxO1. Taken together, the NEFA induced oxidative stress, apoptosis, and steroid hormone synthesis disorders in BGCs by inhibiting the PI3K/AKT pathway that regulates FoxO1 phosphorylation and nuclear translocation. Our findings help to clarify the molecular mechanisms underlying the negative effects of high levels of NEFA on BGCs.

Generalized Self-Efficacy Shields on the Negative Effect of Academic Anxiety on Academic Self-Efficacy During COVID-19 Over Time: A Mixed-Method Study

This two-wave longitudinal study demonstrates the important role of generalized self-efficacy in enhancing online education for Pakistan’s university students during COVID-19. Four hundred and two students participated in the study at both Time 1 and Time 2. Generalized self-efficacy and academic anxiety based on online classes was assessed at Time 1, whereas academic self-efficacy at Time 2. Results indicated that moderate and high levels of generalized self-efficacy shield the negative effects of higher levels of academic anxiety on academic self-efficacy over time. Results suggest that generalized self-efficacy—as a positive resistance resource factor—may gradually coalesce into academic self-efficacy (domain-specific self-efficacy), which at first may be underdeveloped in students in the face of academic anxiety emanating from their online classes during COVID-19 (the novel challenging situation). Further, students’ coded responses revealed ten major sources of academic anxiety emanating from their online classes including internet connectivity issues, increased academic demands, lack of active engagement in online classes, inability to understand difficult topics, and ambiguous internal assessment criteria. Findings suggest implementing interventions for students focusing on instilling internal resources embodied in generalized self-efficacy, conducting active and engaging online classes based on emotionalized learning experiences, and increasing the overall efficacy of teaching and learning during the pandemic through the implementation of a meaningful blended learning approach—based on an online learning mode and an offline personal and collaborative learning mode.

Emotional support received moderates academic stress and mental well-being in a sample of Afghan university students amid COVID-19.

Academic stress experienced during the COVID-19 pandemic has triggered high levels of anxiety and depression and other severe mental health issues among university students around the globe. In Afghanistan, there is a paucity of research on the academic and mental health issues of Afghan university students and none pertaining to their academic stress and mental well-being amid the pandemic. This research examines the potential stress-buffering role of emotional support received between academic stress and mental well-being in a sample of Afghan university students during the COVID-19 outbreak. The study sample comprised 508 Afghan university students. An online survey was developed for data collection. Model 1 of the PROCESS macro was used to conduct the moderation analysis. These indicate that moderate and high levels of emotional support received may protect against the negative effects of higher levels of academic stress on mental well-being. This research makes an important contribution to the literature on social support. It may be inferred from the results that Afghan university students who experience academic stress, but have strong emotional support are able to attain greater mental well-being during the COVID-19 outbreak as compared to those with weak emotional support. Results may encourage mental health practitioners, university counselors, education administrators, and faculty to jointly formulate strategies for offering emotional support to Afghan university students.

How fast can you go? the impact of the founding team's history on the time to reach unicorn status

This paper attempts to answer the question “how do some new ventures grow faster than others?”. Building on the group composition and entrepreneurship literatures, we understand entrepreneurial team members as both carriers of distinct functional skills and personal experiences. Hence, we argue that the entrepreneurial team’s composition, in terms of both the diversity of the team’s functional skills and the familiarity among members, influence new venture performance, in particular growth speed. We use original data on 248 unicorn ventures and their respective founders to test our hypotheses. Our findings suggest that the diversity of the founding team’s skills decreases the time it takes the venture to reach unicorn status, but only up to a threshold after which, increases in team diversity increase the time it takes the venture to reach a billion-dollar valuation. Our findings also suggest that joint experiences among the founding team’s members not only accentuate the positive effect of low-levels of skills’ diversity on the duration to achieve unicorn status, but it also attenuates the negative effect of high levels of skills’ diversity on this duration. We discuss the implications of these results for theory and practice.

Fungal richness does not buffer the effects of streams salinization on litter decomposition

Freshwater salinization is a world-wide phenomenon threatening stream communities and ecosystem functioning. In these systems, litter decomposition is a main ecosystem-level process where fungi (aquatic hyphomycetes) play a central role linking basal resource and higher levels of food-web. The current study evaluated the impact of aquatic hyphomycete richness on leaf litter decomposition when subjected to salinization. In a microcosm study, we analysed leaf mass loss, fungal biomass, respiration and sporulation rate by fungal assemblages at three levels of species richness (1, 4, 8 species) and three levels of salinity (0, 8, 16 g NaCl L‑1). Mass loss and sporulation rate were depressed at 8 and 16 g NaCl L‑1, while fungal biomass and respiration were only negatively affected at 16 g L‑1. A richness effect was only observed on sporulation rates, with the maximum values found in assemblages of 4 species. In all cases, the negative effects of high levels of salinization on the four tested variables superimposed the potential buffer capacity of fungal richness. The study suggests functional redundancy among the fungal species even at elevated salt stress conditions which may guarantee stream functioning at extreme levels of salinity. Nonetheless, it also points to the possible importance of salt induced changes on fungal diversity and identity in salinized streams able to induce bottom-up effects in the food webs.

Paying Enough but not Paying too Much When There is no Third-Party Endorsement: Executive Compensation and Individual Donations for Nonprofit Organizations

We examine whether third-party endorsement and institutional trust can mitigate the potential negative effects of higher levels of executive compensation on the likelihood of future donations to a nonprofit organization. Using an experimental design, we find support for prior expectations that paying higher executive compensation reduces the likelihood of future individual donations. We also find that this negative effect is only significant in the absence of a third-party endorsement so that individual donations significantly decrease when the nonprofit pay is high relative to moderate executive compensation levels. Finally, the likelihood of future individual donations is higher when institutional trust is high. However, high institutional trust does not validate the payment of higher levels of executive compensation. Our results have theoretical and practical implications by showing that nonprofits are better off paying moderate executive compensation levels but not paying too much if they have not attracted respectable third-party endorsers.

Is Healthy Neuroticism Associated with Longevity? A Coordinated Integrative Data Analysis.

Individual differences in the Big Five personality traits have emerged as predictors of health and longevity. Although there are robust protective effects for higher levels of conscientiousness, results are mixed for other personality traits. In particular, higher levels of neuroticism have significantly predicted an increased risk of mortality, no-risk at all, and even a reduced risk of dying. The current study hypothesizes that one potential reason for the discrepancy in these findings for neuroticism is that interactions among neuroticism and other key personality traits have largely been ignored. Thus, in the current study we focus on testing whether the personality traits neuroticism and conscientiousness interact to predict mortality. Specifically, we borrow from recent evidence of "healthy neuroticism" to explore whether higher levels of neuroticism are only a risk factor for increased mortality risk when conscientiousness levels are low. We conducted a pre-registered integrative data analysis using 12 different cohort studies (total N = 44,702). Although a consistent pattern emerged of higher levels of conscientiousness predicting a reduced hazard of dying, neuroticism did not show a consistent pattern of prediction. Moreover, no study provided statistical evidence of a neuroticism by conscientiousness interaction. The current findings do not support the idea that the combination of high conscientiousness and high neuroticism can be protective for longevity. Future work is needed to explore different protective factors that may buffer the negative effects of higher levels of neuroticism on health, as well as other behaviors and outcomes that may support the construct of healthy neuroticism.

Determining the effect of folate diets during pregnancy and lactation on neurobehavioural changes in the adult life of offspring.

ObjectivesAnimal and human studies have demonstrated that folic acid (FA) is essential for nervous system and brain development. In humans, insufficient maternal FA intake is known to cause neural tube defects, autism spectrum, and other neurodevelopmental disorders in children. The present study aimed to determine the impact of maternal FA supplementation on psychomotor skills and learning and memory functions in their adult offspring.MethodsEighteen female Wistar rats were randomly divided into three groups. The animals were fed three different concentrations of FA from preconception to pregnancy and during lactation. The adult offspring were assessed for neurobehavioural changes and histological confirmation by hippocampal neuron quantification.ResultsNeurobehavioural assessment revealed a significantly smaller number of alternations, a higher percentage bias, and a greater number of working and reference memory errors. The increased time spent in the dark compartment in the FA-supplementation group indicated deficit(s) in learning memory. Hippocampal neuron quantification revealed a higher mean number of viable neurons in the cornu ammonis (CA) region in the control group (CA1 region, 31.2 ± 3.2; CA3 region, 23.2 ± 3.2), with a distinct nucleus in both regions, and least in the FA-supplementation group (CA1 region, 24.2 ± 3.1; CA3 region, 15.2 ± 2.2).ConclusionResults of this investigation support the possible negative effect of high levels of maternal FA supplementation during pregnancy and lactation. Such alterations potentially lead to neurobehavioural changes in the adult offspring of Wistar rats.

Changes in sedentary time are associated with changes in mental wellbeing over 1 year in young adults

Excessive sedentary time is related to poor mental health. However, much of the current literature uses cross-sectional data and/or self-reported sedentary time, and does not assess factors such as sedentary bout length. To address these limitations, the influence of objectively measured sedentary time including sedentary bout length (i.e. <30 min, ≥30 min) on mood, stress, and sleep, was assessed in 271 healthy adults (49% women; age 27.8 ± 3.7) across a 1-year period between 2011 and 2013 in Columbia, SC. Participants completed the Profile of Mood States and the Perceived Stress Scale, and wore a Sensewear Armband to assess sedentary time, physical activity, and sleep for ten days at baseline and one year. A series of fixed-effects regressions was used to determine the influence of both baseline levels and changes in daily sedentary time (total and in bouts) and physical activity on changes in mood, stress, and sleep over one year. Results showed that across the year, decreases in total sedentary time, and time in both short and long bouts, were associated with improvements in mood, stress and sleep (p < 0.05). Increases in physical activity were only significantly predictive of increases in sleep duration (p < 0.05). Thus, reductions in sedentary time, regardless of bout length, positively influenced mental wellbeing. Specifically, these results suggest that decreasing daily sedentary time by 60 min may significantly attenuate the negative effects of high levels of pre-existing sedentary time on mental wellbeing. Interventions manipulating sedentary behavior are needed to determine a causal link with wellbeing and further inform recommendations.

An Investigation to the Vermicompost Efficacy on the Activity Level of Antioxidant Enzymes and Photosynthetic Pigments of Borage (Borago officinalis L.) under Salinity Stress Conditions

Salinity stress is one of the most important factors that limit the growth and yield of agricultural crops in arid and semi-arid regions. Activation of the antioxidant system in plants acts as a defense mechanism to build tolerance against salinity. The present factorial experiment was carried out in a completely randomized design. with four replications to evaluate the effect of salinity and application of vermicompost on the activity level of antioxidant enzymes and photosynthetic pigments borage (Borage officinalis L.) under salinity stress conditions. The study treatments consist of four vermicompost levels (0, 5, 10 and 15 wt % potted soil in dry weight) and four salinity levels (0 (control), 4, 8 and 12 ds/m sodium chloride (NaCl)). The results of analysis of variance (ANOVA) showed the considerable influence of salinity stress and vermicompost on the activity level of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), catalase (CAT) and total chlorophyll enzymes. The findings indicated that incremental salinity increased the activity level of antioxidant enzymes and decreased photosynthetic pigments. The results showed that the use of vermicompost fertilizer raised the levels of chlorophyll a, chlorophyll b and carotenoids significantly compared to the control. Based on the comparison of means of the interactions between salinity stress and vermicompost the maximum activity of antioxidant enzymes was obtained by 15 wt % vermicompost treatment at the salinity level of 12 ds/m NaCl. Therefore, the use of vermicompost as an organic fertilizer, in addition to increasing the activity of antioxidant enzymes and photosynthetic pigments, can be a good way to reduce the negative effects of high levels of sodium and chlorine in soils on the growth of borage.

How does emotional conflict affect innovation behavior?

PurposeThis study aims to offer insights regarding the impact of emotional conflict on innovation behavior. This study also explores the boundary conditions by examining the moderating effects of leader-member exchange (LMX) and team-member exchange (TMX) on the relationship between emotional conflict and innovation behavior.Design/methodology/approachThis study used a questionnaire survey to collect data in China. Hypotheses were tested using hierarchical regression analysis. To test for inverted U-shaped relationship between emotional conflict and innovation behavior, the authors computed the squared term for emotional conflict. To investigate moderating roles of LMX and TMX, the authors carried out an interaction term between the main effect variables (emotional conflict and emotional conflict2) and the moderating variables (LMX and TMX).FindingsThe empirical findings indicated that emotional conflict had an inverted U-shaped relationship with innovation behavior. Furthermore, LMX and TMX moderated the inverted U-shaped relationship between the emotional conflict and innovation behavior in such a way that the inverted U-shaped relationship was flatter in high-quality LMX and TMX than in low-quality LMX and TMX. That is to say, LMX and TMX may dampen the positive effects of lower levels of emotional conflict on innovation behavior; yet, it may also weaken the negative effects of higher levels of emotional conflict on innovation behavior.Research limitations/implicationsThis research can be extended in several ways. First, future research can investigate the impact mechanism of emotional conflict on innovation behavior. Second, future research can analyze other types of moderators at different levels. The last but not the least, future research can test the results using heterogeneous samples. Despite these potential limitations, this study provides an elaborate understanding of the conflict–creativity relationship by outlining the inverted U-shaped relationship between emotional conflict and innovation behavior under the LMX and TMX contexts, which can make important contributions to the conflict management literature.Practical implicationsThe findings of this study offer some guidance on how to stimulate innovation behavior through emotional conflict. It suggests that managers should maintain the emotional conflict at the moderate level. Furthermore, managers can strengthen the LMX and TMX to avoid the negative effects of high levels of emotional conflict, and several practices are provided as well.Originality/valueThis study develops an exhaustive understanding of the conflict–creativity relationship by figuring the curvilinear relationship between emotional conflict and innovation behavior, which is the response to the call of Posthuma to focus on the outcomes of conflict management. The findings further provide an empirical evidence of the conceptual argument that the consequences of conflict depend on the situational context by pointing out the important contingency factors of LMX and TMX.

Markers for cognitive impairments and variability of glycaemia in patients with type 1 diabetes mellitus

To analyze the relationship between the markers of cognitive impairment and the variability of glycaemia in patients with DM type 1. Patients with DM type 1 and people without DM (the control group) were examined. Neuropsychological testing (MoCA-test), brain MRI and proton magnetic resonance spectroscopy of the brain, as well as parameters of carbohydrate metabolism (fasting blood glucose, glycated hemoglobin and glycemic variability coefficients) were used. Data on the decrease in the overall performance of the MoCA-test (in particular, on assignments to memory and attention domains), atrophic changes in the cerebral cortex and violations of the content of the main metabolites of brain cells in patients with DM type 1 in comparison with the control group were obtained. A number of positive and negative correlations between these disorders and coefficients of glycemic variability were found in patients with DM type 1. The results suggest a significant negative effect of high levels of glycaemia variability on cognitive functions in patients with DM type 1.

An eye on your work: How empowerment affects the relationship between electronic surveillance and counterproductive work behaviours

Attitudes towards surveillance in the workplace play an important role in determining whether surveillance systems and practices have a positive or negative impact on work behaviour. A survey study of employed Australians (n = 406) was used to test a model in which attitudes towards workplace surveillance were hypothesised to mediate the relationship between perceived level of surveillance at work and counterproductive work behaviours (CWBs). In accordance with expectations, higher levels of perceived surveillance were associated with more CWB, and this relationship was mediated by attitudes towards surveillance. We also theorised that work empowerment may act as a potential buffer against the impact of unfavourable surveillance attitudes on CWBs. Support was also found for this hypothesis as unfavourable surveillance attitudes were not associated with adverse work behaviour among employees who reported higher levels of work empowerment. We discuss how work design and leadership practices can be utilised to build a sense of empowerment in relation to employees’ work with the aim of attenuating some of the potentially negative effects of high levels of surveillance.

Effects of various dietary levels of copper hydroxychloride on growth performance and tissue response in Pacific white shrimpLitopenaeus vannameifed practical diets

Two trials were conducted to evaluate the performance of Pacific white shrimp Litopenaeus vannamei offered diets containing various copper (Cu) levels from Cu hydroxychloride (Cu2(OH)3Cl) containing 58.81% copper in the clear water recirculating system. In both trials, the basal diet (360 g kg−1 protein, 80 g kg−1 lipid) containing approximately 10 mg Cu kg−1 was primarily comprised of fishmeal, soybean meal, corn protein concentrate and whole wheat. In trial 1, test diets were produced supplementing the basal diet with 5, 10, 20, 40 and 60 mg Cu kg−1 from Cu hydroxychloride. Four replicate groups of 15 shrimp per tank (initial weight 0.28 g) were offered diets in slight excess over 8 weeks. In trial 2, the basal diet was supplemented with 30, 90, 150, 210 and 270 mg Cu kg−1 from Cu hydroxychloride. Seven replicate groups of 15 shrimp per tank (initial weight 0.22 g) were offered feed in slight excess over 7 weeks. At the end of the two growth trials, no significant differences were observed in final biomass, final mean weight, percentage weight gain, feed conversion ratio (FCR) and survival. In trial 1, the Cu concentrations of the carapace, hepatopancreas and whole shrimp linearly increased with increasing dietary Cu supplements. In trial 2, polynomial regression of Cu concentrations of the carapace, hepatopancreas and whole shrimp against analysed dietary Cu content indicated that a plateau was reached at 215 mg analysed Cu kg−1. Results of this study indicate that there was no negative effect of high levels of Cu supplement with regard to growth and survival. Tissue levels generally increased up to around 200 mg Cu kg−1 diet and then decreased, possibly indicating a shift in physiology.