Adaptation of Striped Bass to Sea Water Following Direct Transfer from Freshwater: Morphological, Biochemical, and Physiological Parameters

There has been heightened interest in the biology of striped bass (Morone saxatilis) because of increased pollution in their native spawning grounds and because of their extensive use in landlocked sport fisheries. Their euryhalinity makes them an excellent species for osmoregulation studies. The objective of this research was to study the rate of adaptation of striped bass gills to sea water (3% salt) after direct transfer from freshwater using biochemical (ion transport enzyme levels), physiological (chloride efflux), and ultrastructural methods. Striped bass have specialized osmoregulatory cells located on the interlamellar and afferent surfaces of their gill filaments as shown by light microscopy (LM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). SEM studies show that apical pit (opening of one or more chloride cells) morphology changes during sea water adaptation, and the number of apical pits increases by 32.5% after two weeks in sea water. Chloride cell size and number, extent of basolateral tubular system, and number of mitochondria per chloride cell appear to increase upon adaptation to sea water. Sodium-potassium adenosine triphosphatase (Na,K-ATPase) activity is maximal on day 3 after transfer to sea water. Studies suggest that cortisol may act as a hormonal mediator for long term adaptation to sea water. The general morphology of both freshwater and sea water adapted fish gills were studied. Preliminary studies indicate that the osmium-dimethylsulfoxide-osmium method can be used to investigate intracellular structural changes in striped bass gills. Since the chloride cells are associated with the afferent surface of the filament, the blood supply to that area is also of great interest in osmoregulation studies. Studies of the gill vasculature using corrosion casting (i.e. filling blood vessels with plastic resins) and SEM indicate that the blood vessel distribution in the striped bass gill is similar to that of other euryhaline species with arterio-arterial, arterio-venous, and nutritive pathways. Blood flow may be controlled at a variety of places by sphincters, shunts and cellular contraction. Correlation of these biochemical, physiological and anatomical measurements will aid in the understanding of the process of adaptation to sea water. (Abstract shortened with permission of author.

Social influences on drivers in China

China is one of Asia’s many rapidly-motorising nations and recent increases in private-vehicle ownership have been coupled with an escalation in novice drivers. Several pieces of road safety legislation have been introduced in recent decades in China. While managing the legal aspects of road use is important, social influences on driver behaviour may offer alternative avenues to alter behaviour, particularly in a culture where such factors carry high importance. This paper reports qualitative research with Beijing drivers to investigate social influence factors that have, to date, received little attention in the literature. Findings indicated that family members, friends, and driving instructors appear influential on driver behaviour and that some newly licensed drivers seek additional assistance to facilitate the transition from learning to drive in a controlled environment to driving on the road in complex conditions. Strategies to avoid detection and penalties for inappropriate road use were described, many of which involved the use of a third person. These findings indicate potential barriers to implementing effective traffic enforcement and highlight the importance of understanding culturally-specific social factors relating to driver behaviour

Arab Health Promoters’ Perspectives on Religious/Cultural Challenges to Adopt Healthy Lifestyle Behaviours among Arab Immigrants in Canada

Despite the importance of faith and cultural background in Arab immigrants’ lives, little is known about their role in preventing cardiovascular diseases. To understand the challenges among Arab immigrants related to acculturation and religiosity in adopting healthy lifestyle behaviours and managing stress, we conducted three face-to-face focus groups with 17 Arab health promoters who were members of the Canadian Arab Health Coalition. Averaging 80 minutes in length, the focus groups were conducted in Ottawa, Canada, in February and March 2018. Data were analyzed with an inductive thematic analysis approach; we identified four themes: “Culture first!”: dominant influence of home country culture; “Religiosity alone does not make you healthy!”: limited religious influence; “It is not easy!”: difficulties adapting to the Canadian lifestyle; and “We are not young!”: generational differences in adopting a healthy lifestyle. In brief, we found that some religious or cultural beliefs may be barriers to practicing physical activity, especially for women and older people. These barriers may be augmented with acculturative stress. Religiosity may also play an important indirect role in managing stress through socialization, family support, and the adoption of coping strategies. Younger people in Arabic communities appear to be more flexible in dealing with these religious/cultural issues

The Gill Arch of the Striped Bass, Morone Saxatilis. II. Microvasculature Studied with Vascular Corrosion Casting and Scanning Electron Microscopy

The gill vasculature of euryhaline striped bass, Morone saxatilis, was examined by scanning electron microscopy of corrosion casts prepared by injecting resin (either Mercox/Sevriton or L.R. White) into the ventral aorta. The vasculature of the striped bass gill appears to be similar to that of other euryhaline species. The striped bass gill has three major vascular systems: (1) a respiratory system, (2) an arterio-venous system, and (3) a nutritive system. In the respiratory system, blood from the afferent branchial artery flows to each filament via an afferent filamental artery, and from there to the highly vascularized respiratory lamellae. Lamellar blood is conducted back to the efferent branchial artery via the efferent filamental artery. In the second system arterio-venous anastomoses transport blood from the efferent filamental artery to the central venous sinus. Blood then flows to the branchial vein either directly or via paired afferent companion vessels. No arterio-venous anastomoses connecting the prelamellar vessels with the central venous sinus have been found. Finally, nutritive branches to the arch are provided by the efferent branchial artery and the efferent filamental artery. The striped bass does not have a lamellar bypass system involving the central venous sinus as reported in other species. Intralamellar distribution mechanisms and lamellar recruitment may account for changes in respiratory lamellar perfusion during decreased and increased oxygen demand, respectively. The central venous sinus\u27 role may be partially nutritional since its blood is oxygenated. However, its complex vascular connections may permit a variety of other functions

Managing stakeholder \u27push back\u27, an exploratory investigation into dealing with negative cross cultural communication in a global environment

This paper addresses the issue of a current business phenomenon &ndash; &lsquo;push back&rsquo;. This phenomenon has been experienced by a number of transnational companies. It is embedded in the challenges of cross-cultural communication and involves the linkage of local culture activists with globalisation acitivists in an alliance to stop business growth. This exploratory investigation examines three multinational organisations using qualitative research. From the findings a model has been developed in an attempt to provide practitioners with a framework with which to understand &lsquo;push back&rsquo;. The complexity of combating alliances of this nature raises challenges for the current approaches to marketing and the need for a multi-stakeholder approach in cross-cultural communication is suggested.<br /

A ternary mechanism for NADH oxidation by positively charged electron acceptors, catalyzed at the flavin site in respiratory complex I

AbstractThe flavin mononucleotide in complex I (NADH:ubiquinone oxidoreductase) catalyzes NADH oxidation, O2 reduction to superoxide, and the reduction of several ‘artificial’ electron acceptors. Here, we show that the positively-charged electron acceptors paraquat and hexaammineruthenium(III) react with the nucleotide-bound reduced flavin in complex I, by an unusual ternary mechanism. NADH, ATP, ADP and ADP-ribose stimulate the reactions, indicating that the positively-charged acceptors interact with their negatively-charged phosphates. Our mechanism for paraquat reduction defines a new mechanism for superoxide production by complex I (by redox cycling); in contrast to direct O2 reduction the rate is stimulated, not inhibited, by high NADH concentrations

The Measurement of Information Systems Effectiveness: Evaluating a Measuring Instrument

Information system effectiveness is an important phenomenon for both researchers and practitioners. Despite widespread interest, and the importance of the uses, there have been no efforts to validate CompufemorM’sPremier 100 rankings of information system effectiveness. This paper uses structural equation modeling in an attempt to validate the measuring instrument usee to derive the Computerworld rankings. Alternative models for the measuring insrrument are proposed. TJsing a .reflective model, the findings raise doubts as to the reliability of the rankings, and both conteni validity 2nd construct validity are also suspect. The reliability and validity are problematic because multiple indicators of the same consvict must be homogeneous for it to make sense to combine them into a conposite index. A solution to this problem is to represent information system effectiveness as a multidimensional construct that is part of a causal model. Based on previous research in the area, suggestions are offered to improve the measuring instrument

Mentoring Experiences of Aging and Disability Rehabilitation Researchers

Objectives. To explore research mentoring experiences and perceived mentoring needs of aging and disability researchers at different career stages. Design. Focus group and individual interviews with rehabilitation researchers at various career stages based in hospitals, universities, and hospital-based research institutes in Ontario, Canada. Results. The overall theme was mentoring for transition. Participants across career stages referred to helpful mentoring experiences as those that assisted them to move from their previous stage into the present stage or from the present stage into their next career progression. Unhelpful mentoring experiences were characterized by mentor actions that were potentially detrimental to transition. Subsumed under this theme were three categories. The first, “hidden information” referred to practical information that was difficult to access. The second “delicate issues” referred to helping the participant work through issues related to sensitive matters, the discussion of which could put the participants or their colleagues in a vulnerable position. The third category was “special challenges of clinician-researchers”. Conclusions. Helpful mentoring for rehabilitation researchers working on concerns related to aging and disability appears to be characterized by interaction with more experienced individuals who aid the researcher work through issues related to career transition

Rubrics: A Method for Surfacing Values and Improving the Credibility of Evaluation

Background: The challenges of valuing in evaluation have been the subject of much debate; on what basis do we make judgments about performance, quality, and effectiveness? And according to whom? (Julnes, 2012b). There are many ways identified in the literature for carrying out assisted valuation (Julnes, 2012c). One way of assisting the valuation process is the use of evaluative rubrics. This practice-based article unpacks the learnings of a group of evaluators who have used evaluative rubrics to grapple with this challenge. Compared to their previous practice, evaluative rubrics have allowed them to surface and deal with values in a more transparent way. In their experience when evaluators and evaluation stakeholders get clearer about values, evaluative judgments become more credible and warrantable. Purpose: Share practical lessons learned from working with rubrics. Setting: Aotearoa (New Zealand). Intervention: Not applicable. Research Design: Not applicable. Data Collection and Analysis: Not applicable. Findings: They have found that while evaluative rubrics look beguilingly simple they are hard to do well. However, when done well, evaluative rubrics can substantially increase the use and credibility of evaluation.Keywords: Rubrics; values; valuation; stakeholder; validity; credibility; utilit