The ontogeny of respiration in herring and plaice larvae

The study of larvae, their behaviour & physiology has gathered momentum in recent years due to the development of improved techniques of rearing during the past decade. Many marine larvae have been successfully reared in the laboratory (Shelbourne, 1964; Schumann, 1967; Blaxter, 1968,1969; Houde & Palko, 1970; Futch & Detwyler, 1970; Lasker, Feder, Theilacker & May, 1970). Fish larvae, in particular those of most marine species form an important tool for research in that at hatching they only possess the rudiments of most organs. Thus they are ideal material for ontogenetical studies. Although the respiratory mechanisms of adult fish have been the subject of a great deal of investigation from the point of view of gas exchange (see Randall 1970) gill structure (Hughes, 1966; Hughes & Grimstone, 1965; Newstead, 1967; to name a few) and dimensions (see Muir, 1969) gill ventilation and perfusion (see Shelton, 1970) circulatory systems (see Randall, 1970) bioenergetics, (see Brett, 1970) the respiratory systems of larvae have not been investigated in any great detail. Apart from a few studies on oxygen uptake (see Blaxter, 1969) and Harder (1954) on the development of branchial elements, no detailed study of the development of respiratory mechanisms have been made in marine fish larvae. The purpose of this study was to investigate the development of respiration in two species of marine larvae viz. the herring (Clupea harengus L.) and the plaice (Pleuronectes plates sa L.) These two species are well separated taxonomically and both adults and young have very different life histories. Herring lay demersal eggs, the plaice pelagic ones. The yolk-sac larvae of both species are planktonic, later feeding on diatoms and copepod nauplii and much later copepods. Adult herring are pelagic, living in mid water as juveniles and moving into deeper water with age, ranging from offshore to about 200m. They perform migrations partly caused by the distribution and density of food organisms. In contrast to this plaice at metamorphosis show an interesting asymmetry in that one eye migrates over the head and comes to lie against its opposite number. At this stage pelagic life ceases and the young fish assumes a bottom-living existence. Other features associated with asymmetry are secondary to the migration of the eye and follow on from the adoption of the benthic mode of life. They range from the shoreline when young to lOOOm feeding on bottom living organisms. During development the mechanism of respiration changes from a cutaneous one to gill respiration typical of the adult form. There is apparently no respiratory pigment in the early stages but the blood becomes pink at metamorphosis. The problem was approached from a morphological and a physiological viewpoint. The main parts of the study are as follows. (1) The survival times in water of low oxygen concentrations. (2) The oxygen uptake at normal oxygen concentrations. (3) The oxygen uptake at low oxygen concentrations. (4) Measurement of the body surface area as well as the gill area available for respiration. (5) The appearance of haemoglobin and its quantitative measurement

A Qualitative Study of the Process Undergraduate Health Professions Students Utilize while Conducting a Scoping Review

Purpose: The purpose of this research study was to inform pedagogy on the effectiveness of journaling as a tool to gauge synthesis and application of course content to a scoping review. The research question asked is “Is reflective journaling effective in helping undergraduate health profession students understand and apply course research concepts and ideas directly to an academic project?” The researchers used a reflective journaling activity to enhance student learning and to explore student application of course lectures to a scoping literature review. Method: Students were required to complete the journaling activities as a class assignment. Four journal entries were aimed at understanding student application of steps of scoping review and how students applied course content to a specific project; a final journal entry was reflective on lessons learned through the process. Results: Student journal entries provided detail on synthesis and application of course lectures to a student specific scoping literature review. Students identified challenges experienced such as trouble in finding literature; selecting and using the most appropriate keywords; lack of evidence-based, discipline specific research; finding recent research (i.e., within the last 10 years); and narrowing the topic to a manageable size. Successes include demonstrating student understanding of areas such as writing the research question and collaboration. As the project progressed, concerns shifted to writing barriers, team issues, the “choppiness” of writing with multiple authors, and organizing the flow of the paper. In the final journal entry, students reported that the project helped them learn how to apply research to practice, increased their skill and comfort in presenting research and education to others, and improved their skills in doing more effective literature searches and using keywords. Course lectures were adapted based on student journal entries to increase student comprehension and application, which were effective in improving student work as the project progressed. Conclusions: The student journal entries were effective in demonstrating their learning and application of course content to a specific project. Students benefitted from the opportunity to reflect on their process, problems, and strategies. For the instructor, journal entries provided an opportunity to see where students were at in the process, identified barriers, and allowed adaptations to instruction to provide feedback or further guidance. Other findings from this study reinforced previous studies on journaling outside of health professions, such as the value of having direct access to the librarian for guidance, the opportunity journaling provides for in-the-moment lessons and learning from students’ reflections, and that journaling activities provide for accountability with timely completion of assignments

The appeal of the Functional Fitness MOT to older adults and health professionals in an outpatient setting: a mixed-method feasibility study

Purpose: To understand the views and perceptions regarding the Functional Fitness MOT (FFMOT), a battery of functional tests followed by a brief motivational interview, of both the older people undergoing it and the health professionals delivering it. Patients and methods: Physically inactive older adults (n=29) underwent the FFMOT and subsequently attended focus groups to share their perceptions of it and to discuss the barriers, motivators, health behavior change, and scope to improve physical activity (PA) levels. PA levels were recorded at baseline and again at 12 weeks together with a post-intervention questionnaire concerning behavior change. Participating physiotherapists and technical instructors were interviewed. Results: Most participants felt they had learned about their abilities and comparisons with their peers, had a change in perception about the importance of good balance and strength, and felt the FFMOT helped raise their awareness of local and self-directed physical activity opportunities. Most felt their awareness of the need for PA had not changed, but 25% of participants started a new organized PA opportunity. The health professionals perceived the FFMOT as being easy to administer, educating, and motivating for participants to increase their PA. Space, time, finances, and insecurity about having the necessary skills to conduct the FFMOTs were seen as barriers in implementing the FFMOT in daily practice. Conclusion: Over half of those offered the FFMOT accepted it, suggesting it is appealing. However, most participants felt they were already active enough and that their awareness of the need for PA had not changed. There were positive perceptions of the FFMOT from both professionals and older people, but both felt the FFMOT could be held in a community venue. The overall findings suggest that the FFMOT is feasible in the clinical setting, but its effectiveness has yet to be determined

2009 Archaeological Investigations at the Walters, Beedle, and Lyon Lots, Lincoln Home National Historic Site

Established in 1971, the Lincoln Home National Historic Site (LIHO) commemorates the life of the 16th President of the United States. The park contains the neighborhood where Abraham Lincoln spent most of his adult life in Springfield, Illinois (Townsend 2008:76-149). The Park consists of a four-block historic neighborhood, which is partly restored to the year of Abraham Lincoln’s election as President. The centerpiece of the park consists of the restored house where Lincoln’s family lived from 1844 to 1861, when he became the 16th President of the United States

Intra-islet GLP-1, but not CCK, is necessary for β-cell function in mouse and human islets

Glucagon-like peptide 1 (GLP-1) and cholecystokinin (CCK) are gut-derived peptide hormones known to play important roles in the regulation of gastrointestinal motility and secretion, appetite, and food intake. We have previously demonstrated that both GLP-1 and CCK are produced in the endocrine pancreas of obese mice. Interestingly, while GLP-1 is well known to stimulate insulin secretion by the pancreatic β-cells, direct evidence of CCK promoting insulin release in human islets remains to be determined. Here, we tested whether islet-derived GLP-1 or CCK is necessary for the full stimulation of insulin secretion. We confirm that mouse pancreatic islets secrete GLP-1 and CCK, but only GLP-1 acts locally within the islet to promote insulin release ex vivo. GLP-1 is exclusively produced in approximately 50% of α-cells in lean mouse islets and 70% of α-cells in human islets, suggesting a paracrine α to β-cell signaling through the β-cell GLP-1 receptor. Additionally, we provide evidence that islet CCK expression is regulated by glucose, but its receptor signaling is not required during glucose-stimulated insulin secretion (GSIS). We also see no increase in GSIS in response to CCK peptides. Importantly, all these findings were confirmed in islets from non-diabetic human donors. In summary, our data suggest no direct role for CCK in stimulating insulin secretion and highlight the critical role of intra-islet GLP-1 signaling in the regulation of human β-cell function

Virtual collaborative spaces: a case study on the antecedents of collaboration in an open source software community

Collaboration enables the sharing amongst individuals of resources and knowledge required to innovate. In recent years, this phenomenon has increasingly manifested in virtual collaborative spaces such as open-source software communities because of the advancement in the use of online technologies and the heightened need for distance work. However, it is still unclear which underlying mechanisms foster collaboration in these spaces. By using the Linux kernel open-source software community as a case study, we analyze data from the [email protected] mailing list to model the influence of proximity on the likelihood of collaboration between individuals. Our dataset is composed of 10,513 message replies to the PCI mailing list posted by its 654 active members in the years 2013 to 2015. Our results show that geographical proximity does not have a direct impact on collaboration, while organizational features defined by institutional and organizational proximity do significantly affect collaboration. Cognitive and social proximity also significantly, and positively, affects collaboration, but these relationships show an inverted u-shaped form. Our results confirm the need to develop specific theorizing about virtual spaces, as they present unique features when compared to traditional physical environments.Peer reviewe

Sitting time and patterns of activity in post-stroke rehabilitation: week versus weekend activity

Background: High levels of active task practice are recommended after stroke. However, the in-patient rehabilitation day is largely spent sitting. Understanding patterns of sitting across the rehabilitation week may facilitate strategies to promote greater activity. We aimed to compare differences in weekday and weekend sitting time and 24-hour activity patterns during the last week of in patient rehabilitation. Methods: Participants with stroke (n=34) from two rehabilitation units wore an activity monitor continuously during the final 7-days of in-patient rehabilitation. Linear mixed models (adjusted for waking hours) were performed with activity time as the outcome and weekday and weekend as the exposure. Patterns of activity accumulation were determined by averaging patient activity in 60-minute epochs, and then generating a heat map of activity level as a function of time. Results: Participant mean age was 68 [SD 13] years (53% male) mean NIHSS score 7 [SD 5]. There was no significant difference in total sitting time between weekdays and weekends. On the weekend, mean walking time was 8.35 minutes less (95% CI -12.13, -4.56 p ≤0.001), and steps/day were 624 fewer (95% CI -951, -296 p ≤0.001) than during the week. Activity patterns were similar across weekdays and weekends, with more morning than afternoon activity observed. Conclusion: Sitting time did not change in relation to the 7-day rehabilitation week, while walking (time and steps) was less on weekends. Morning activity was observably greater than afternoon activity across the 7-days. Strategies targeting afternoon, evening and weekend activity may increase overall physical activity during rehabilitation

The Low Quiescent X-Ray Luminosity of the Transient X-Ray Burster EXO 1747-214

We report on X-ray and optical observations of the X-ray burster EXO 1747-214. This source is an X-ray transient, and its only known outburst was observed in 1984-1985 by the EXOSAT satellite. We re-analyzed the EXOSAT data to derive the source position, column density, and a distance upper limit using its peak X-ray burst flux. We observed the EXO 1747-214 field in 2003 July with the Chandra X-ray Observatory to search for the quiescent counterpart. We found one possible candidate just outside the EXOSAT error circle, but we cannot rule out the possibility that the source is unrelated to EXO 1747-214. Our conclusion is that the upper limit on the unabsorbed 0.3-8 keV luminosity is L < 7E31 erg/s, making EXO 1747-214 one of the faintest neutron star transients in quiescence. We compare this luminosity upper limit to the quiescent luminosities of 19 neutron star and 14 black hole systems and discuss the results in the context of the differences between neutron stars and black holes. Based on the theory of deep crustal heating by Brown and coworkers, the luminosity implies an outburst recurrence time of >1300 yr unless some form of enhanced cooling occurs within the neutron star. The position of the possible X-ray counterpart is consistent with three blended optical/IR sources with R-magnitudes between 19.4 and 19.8 and J-magnitudes between 17.2 and 17.6. One of these sources could be the quiescent optical/IR counterpart of EXO 1747-214.Comment: 7 pages, accepted by the Astrophysical Journa