Search

There is increasing concern about the effect of underwater noise on fish due to rising levels of anthropogenic noise. We performed experiments on the black bullhead (Ameiurus melas), a species with known hearing specializations and located within the Laurentian Great Lakes where there is considerable commercial and recreational boat traffic. We tested and compared physiology (baseline cortisol), behaviour (activity, sheltering), and morphology (ciliary bundles of hair cells) of bullhead to boat noise. At 140 dB re 1 [micro]Pa (-54.84 dB re 1 mx[s.sup.-2]), we saw clear behavioural effects in terms of both activity and sheltering levels despite no obvious morphological or physiological stress. Following both short- and long-period acute exposure to higher--but environmentally relevant--noise levels, bullhead were less active and sheltered more and also exhibited a decrease in ciliary bundles. These results suggest that there are sublethal effects of anthropogenic noise on fish behaviour and ciliary bundles, which may have direct implications on population health. Moreover, commonly used metrics such as stress hormones may not always offer the most relevant biomarker of the response to anthropogenic boat noise. L'effet du bruit sous l'eau sur les poissons suscite de plus en plus d'inquietudes en raison des niveaux croissants de bruit d'origine humaine. Nous avons realise des experiences sur la barbotte noire (Ameiurus melas), une espece montrant des specialisations auditives presente dans les Grands Lacs laurentiens, le lieu d'une importante circulation d'embarcations commerciales et recreatives. Nous avons verifie et compare la physiologie (concentration de base de cortisol), le comportement (activite, mise a l'abri) et la morphologie (touffes ciliaires de cellules ciliees) de barbottes noires en presence de bruit d'embarcation. A 140 dB re 1 [micro]Pa (-54,84 dB re 1 mx[s.sup.-2]), nous avons note des effets comportementaux clairs en ce qui concerne les niveaux d'activite et de mise a l'abri, malgre l'absence de stress morphologique ou physiologique evident. Apres des periodes d'exposition aigue courtes et longues a des niveaux de bruit plus eleves, mais toujours pertinents sur le plan environnemental, les barbottes noires etaient moins actives et s'abritaient plus, en plus de presenter une diminution des touffes ciliaires. Ces resultats donnent a penser que le bruit d'origine humaine a des effets subletaux sur le comportement des poissons et les touffes ciliaires, qui pourraient avoir des consequences directes sur la sante des populations. En outre, des parametres couramment utilises comme la concentration d'hormones de stress pourraient ne pas toujours etre les biomarqueurs les plus pertinents de la reaction au bruit d'embarcations. [Traduit par la Redaction], Introduction Anthropogenic noise is now common in aquatic ecosystems, although the effects this has on aquatic animals, particularly freshwater fishes, remains unclear (Slabbekoorn et al. 2010; Popper and Hawkins 2012). [...]

Copyright of Avian Conservation & Ecology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study examines two competing theoretical explanations for why work-life policies such as dependent care assistance and flexible schedules influence organizational attachment. The self-interest utility model posits that work-life policies influence organizational attachment because employee use of these policies facilitates attachment. The signaling model posits that these policies facilitate attachment indirectly through perceived organizational support. Regression analyses explored both models using a sample of 286 full time employees. Results supported both the signaling model and the self-interest utility model. For women, the availability of work-life benefits influenced organizational attachment irrespective of use, and these effects were mediated by support perceptions, consistent with the signaling model. In contrast, the self-interest model was also supported for men only. Specifically, the availability and use of flexible schedules interacted in predicting affective commitment among men such that flexible schedule availability was positively related to commitment only when use was high and negatively related to commitment when use was low. Dependent care assistance and schedule flexibility also interacted in predicting affective commitment, turnover intentions, and perceived organizational support, suggesting that the effect of policy implementation may depend on what other policies are already offered by the organization. Findings are discussed in terms of implications for theory and organizational practice.

Nearly all organisms rely on natural fluctuations of light as cues for synchronizing physiological processes and behavioural actions associated with foraging, growth, sleep and rest, reproduction, and migration. Consequently, although artificial lighting sources have provided a plethora of benefits for humans, they can lead to disruptions for wild organisms. With one quarter of the human population living within 100 km of coastlines, there is great potential for artificial light at night (ALAN) to influence the physiology, behaviour and fitness of fishes. Through a review of the literature (n = 584 publications focused on the effects of ALAN on individual organisms or ecosystems), we illustrate that most papers have concentrated on terrestrial species (59%) compared with aquatic species (20%) or a mixed approach (21%). Fishes have been underrepresented in comparison with many other taxa such as birds, insects and mammals, representing the focus of less than 8% of taxa‐specific publications. While the number of publications per year focusing on fishes has generally been increasing since the mid‐2000s, there has been a downturn in publication rate in the last few years. To understand where research related to ALAN in fishes has been focused, we partitioned studies into categories and found that publications have mostly concerned behaviour (41.0%), abundance and community structure (24.4%), and physiology (22.8%), while the longer‐term effects on fitness (6.9%) are lacking. We synthesize the research completed in fishes and outline future priorities that will help ascertain the short‐ and long‐term consequences of this relatively novel stressor for fish health and persistence. [ABSTRACT FROM AUTHOR]

Research has been conducted on protein farnesyltransferase. The relationship between the zinc(II) center in this farnesyltransferase and the peptide thiolate reactivity alkylated by farnesyl diphosphate has been investigated and the results are presented.

Abstract Backgroundlaims--Abnormalities in the saccadic main sequence are an important finding and may indicate pathology of the ocular motor periphery or central neurological disorders. In young or uncooperative patients it [...]