1,662 research outputs found

    Sodium and Water Fluxes in Free-Living Crocodylus Porosus in Marine and Brackish Conditions

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    Radioactive sodium and water were used to determine total body water (TBW), exchangeable sodium (ExNa) and water and sodium fluxes in free-living Crocodylus porosus in marine (hyperosmotic; salinity = 250/00-350/00) and brackish (hypoosmotic; salinity = 20/00-7.50/00) sections of the Tomkinson River in northern Australia. At capture, size-corrected TBW and ExNa pools in 62 crocodiles (hatchlings, juveniles, and subadults; weight, 0.108-54.4 kg) were independent of salinity history. To determine fluxes, all animals were released at their capture sites and left undisturbed until recapture. Thirty-seven were recaptured after 7-18 days. Fifteen of the 17 hatchlings recaptured from both salinity categories grew and maintained their condition and hydration status. In contrast, all 20 juveniles and subadults lost weight in the same period, and juveniles in hyperosmotic conditions showed significantly lower hydration and condition factors. Water effluxes in hatchlings were ~80 and ~160 ml kg-0.63 day-1 in marine and brackish conditions, respectively. Comparable sodium effluxes were 7.5 and 4.4 mmol kg-0.63 day1. All crocodiles in hyperosmotic conditions had consistently lower water effluxes (~ X0.5) and higher sodium effluxes (~ X 1.6) than did crocodiles in brackish water. In both salinity categories, hatchlings had greater water turnover (~ X 1.3, X 1.6) and sodium turnover (~ X 1.5, X 1.25) than did juveniles and subadults. Interpretation of the field data is complicated by integumentary exchange of sodium and water, a size-related aphagia apparently induced by disturbance, and difficulties of adjusting for allometric differences across a wide range of sizes. Nevertheless, it is clear that C. porosus is able to effect considerable economies of water turnover in hyperosmotic salt water and that the secretory capacity of the lingual glands, as measured in the laboratory, is more than enough to account for the highest sodium effluxes that we measured in C. porosus in the field

    Outdoor air pollution and near-fatal/fatal asthma attacks in children: A systematic review.

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    BACKGROUND: Globally, observational studies have demonstrated an association between high levels of air pollution and asthma attacks in children. It remains unclear whether and to what extent exposure may be associated with increased near-fatal/fatal attacks. OBJECTIVE: To systematically review the evidence for an association between ambient outdoor air pollution and fatal and/or near-fatal asthma (NFA). METHODS: Following Cochrane methodology, we searched MEDLINE, EMBASE, Web of Science, Scopus, and Open Grey electronic databases for studies reporting the association of fatal/NFA and air pollution (particulate matter [PM], sulfur dioxide, nitrogen dioxide, black carbon and ozone [O3 ]) in children. NFA was defined as requiring intensive care unit (ICU) management. RESULTS: Two reviewers independently screened 1358 papers. A total of 276 studies identified asthma attacks related to air pollution, 272 did not meet inclusion criteria after full-text review. Four observational studies described fatal/NFA, of which three addressed NFA. PM2.5 (per 12.5 µg/m3 increase) and O3 (per 22 ppb increase) were associated with NFA in one study (PM2.5, relative risk: 1.26, confidence interval [CI] [1.10-1.44]), O3  (1.19 [1.01-1.40]). PM10 was associated with ICU admission in the context of thunderstorm asthma. Elemental carbon was associated equally with NFA that did not require an ICU admission (p = 0.67). Studies of fatal asthma including children did not demarcate age within the analysis. CONCLUSIONS: Ozone and PM2.5 have been associated with NFA in children but synthesis is limited by the paucity of studies and methodological heterogeneity. Poor reporting of severities of asthma attacks hinders the assessment of whether outdoor air pollution is associated with an increased number of NFA/fatal attacks in children

    On the Use of Inertial Sensors in Educational Engagement Activities

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    Wearable sensors have been successfully used for a few decades in different sporting applications and its use has been constrained mostly to research projects. However, its positive impact has been recently adding other directions towards education, commercial and servicing. The establishment of Sports Engineering as a discipline is playing an important role in Australian universities where relevant material and emerging technologies are required to be taught and in certain circumstances developed. Some of these technologies include the adoption of inertial sensors (accelerometers and gyroscopes). This paper shares the impact of inertial sensors in building engagement in different educational activities at secondary level, with the purpose of engaging them into Sports Engineering disciplines, and at tertiary level through teaching undergraduate and post-graduate programs

    Women’s experiences of transfer from primary maternity unit to tertiary hospital in New Zealand: part of the prospective cohort Evaluating Maternity Units study

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    BACKGROUND: There is worldwide debate regarding the appropriateness and safety of different birthplaces for well women. The Evaluating Maternity Units (EMU) study’s primary objective was to compare clinical outcomes for well women intending to give birth in either a tertiary level maternity hospital or a freestanding primary level maternity unit. Little is known about how women experience having to change their birthplace plans during the antenatal period or before admission to a primary unit, or transfer following admission. This paper describes and explores women’s experience of these changes-a secondary aim of the EMU study. METHODS: This paper utilised the six week postpartum survey data, from the 174 women from the primary unit cohort affected by birthplace plan change or transfer (response rate 73 %). Data were analysed using descriptive statistics and thematic analysis. The study was undertaken in Christchurch, New Zealand, which has an obstetric-led tertiary maternity hospital and four freestanding midwife-led primary maternity units (2010–2012). The 702 study participants were well, pregnant women booked to give birth in one of these facilities, all of whom received continuity of midwifery care, regardless of their intended or actual birthplace. RESULTS: Of the women who had to change their planned place of birth or transfer the greatest proportion of women rated themselves on a Likert scale as unbothered by the move (38.6 %); 8.8 % were ‘very unhappy’ and 7.6 % ‘very happy’ (quantitative analysis). Four themes were identified, using thematic analysis, from the open ended survey responses of those who experienced transfer: ‘not to plan’, control, communication and ‘my midwife’. An interplay between the themes created a cumulatively positive or negative effect on their experience. Women’s experience of transfer in labour was generally positive, and none expressed stress or trauma with transfer. CONCLUSIONS: The women knew of the potential for change or transfer, although it was not wanted or planned. When they maintained a sense control, experienced effective communication with caregivers, and support and information from their midwife, the transfer did not appear to be experienced negatively. The model of continuity of midwifery care in New Zealand appeared to mitigate the negative aspects of women’s experience of transfer and facilitate positive birth experiences

    Conservatism of lizard thermal tolerances and body temperatures across evolutionary history and geography

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    Species may exhibit similar thermal tolerances via either common ancestry or environmental filtering and local adaptation, if the species inhabit similar environments. We ask whether upper and lower thermal limits (critical thermal maxima and minima) and body temperatures are more strongly conserved across evolutionary history or geography for lizard populations distributed globally. We find that critical thermal maxima are highly conserved with location accounting for a higher proportion of the variation than phylogeny. Notably, thermal tolerance breadth is conserved across the phylogeny despite critical thermal minima showing little niche conservatism. Body temperatures observed during activity in the field show the greatest degree of conservatism, with phylogeny accounting for most of the variation. This suggests that propensities for thermoregulatory behaviour, which can buffer body temperatures from environmental variation, are similar within lineages. Phylogeny and geography constrain thermal tolerances similarly within continents, but variably within clades. Conservatism of thermal tolerances across lineages suggests that the potential for local adaptation to alleviate the impacts of climate change on lizards may be limited
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