4,709 research outputs found

    Measurement of bone quality in growing male rats using dual energy x-ray absorptiometry and bone ash content : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Animal Science at Massey University, Palmerston North, New Zealand

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    Growing male rats have been considered and used as a model for bone growth and prevention of osteoporosis because of their high bone turnover and demand for calcium. Dual Energy X-ray Absorptiometry (DEXA) is a useful tool for identifying minimal changes in bone mineral density and has recently been adapted for use in small animal models. The objective of this trial was to identify the changes in Bone Mineral Density (BMD) in relation to age and to identify how BMD varies from site to site. Sixty male Sprague-Dawley rats were split into six groups to allow measurements at one, two, three, four, five and six months of age (n=10 per group). At each time point a group of rats was scanned using a QDR4000 DEXA machine from Hologic. Duplicate BMD measurements were obtained for the whole body, spine and both femurs in vivo. The rats were then euthanased and the spine and both femurs were excised for ex vivo DEXA scanning and ashed calcium analysis. BMD increased almost linearly to four months and then formed a plateau. This indicates that from weaning to four months is an especially sensitive time for manipulating bone growth in male rats. There was a significant difference in BMD between groups (P<0.001), which is to be expected in growing rats. There was also a significant difference in BMD within groups (p<0.001), believed to be due to variation at two and five months of age. There was a very strong positive correlation between weight and BMD and age and BMD at all sites, indicating that BMD is a strongly related to both weight and age. All sites were strongly correlated to each other and to the ashed calcium values. The excised femur had a lower BMD value than the in vivo femur, although the two values were strongly correlated. This is believed to be due to differences in positioning and indicates that the two methods cannot be used interchangeably. These results indicate that bone mineral density is the gold standard for following changes in bone growth over time in the growing rat. Alternatively, ashed bone calcium content can be used, but only as a once off endpoint

    Optical coherence tomography:age estimation of <i>Calliphora vicina</i> pupae <i>in vivo</i>?

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    Necrophagous blowfly pupae are valuable contributors to the estimation of post-mortem interval, should an accurate age estimate be obtained. At present, this is reliant on a combination of rearing and destructive methods conducted on preserved samples, including morphological observation and gene expression analyses. This study demonstrates the use of optical coherence tomography (OCT) as a tool for in vivo morphological observation and pupal age estimation. Using a Michelson OCT microscope, alive and preserved four and ten-day old Calliphora vicina pupae were scanned in different orientations. Two and three-dimensional images were created. Morphological characteristics such as the brain, mouthparts and legs were identifiable in both living and preserved samples, with distinct differences noted between the two ages. Absorption of light by the puparium results in a vertical resolution of 1-2 mm, preventing observation of deeper tissues. The use of contrast agents or a longer wavelength laser would improve the images obtainable. At present, the data suggests OCT provides a primary view of external and internal morphology, which can be used to distinguish younger and older pupae for further analysis of age and PMI estimation

    Are gauge symmetry transformations observable?

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    In a recent paper in the British Journal for the Philosophy of Science, Kosso discussed the observational status of continuous symmetries of physics. While we are in broad agreement with his approach, we disagree with his analysis. In the discussion of the status of gauge symmetry, a set of examples offered by ’t Hooft has influenced several philosophers, including Kosso; in all cases the interpretation of the examples is mistaken. In this paper we present our preferred approach to the empirical significance of symmetries, re-analysing the cases of gauge symmetry and general covariance

    Europa's Optical Aurora

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    Auroral emissions provide opportunities to study the tenuous atmospheres of Solar System satellites, revealing the presence and abundance of molecular and atomic species as well as their spatial and temporal variability. Far-UV aurorae have been used for decades to study the atmospheres of the galilean satellites. Here we present the first detection of Europa's visible-wavelength atomic oxygen aurora at 6300/6364 \AA{} arising from the metastable O(1(^1D) state, observed with the Keck I and Hubble Space Telescopes while Europa was in eclipse by Jupiter on six occasions in February-April 2018. The disk-integrated O(1^1D) brightness varies from <<500 R up to more than 2 kR between dates, a factor of 15 higher than the OI 1356 \AA{} brightness on average. The ratio of emission at 6300/5577 \AA{} is diagnostic of parent molecule; the 5577 \AA{} emission was not detected in our dataset, which favors O2_2 as the dominant atmospheric constituent and rules out an O/O2_2 mixing ratio above 0.35. For an O2_2 atmosphere and typical plasma conditions at Europa's orbit, the measured surface brightness range corresponds to column densities of 1-9×\times1014^{14} cm−2^{-2}

    The Applicability of Behaviour Change in Intervention Programmes Targeted at Ending Female Genital Mutilation in the EU:Integrating Social Cognitive and Community Level Approaches

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    With increased migration, female genital mutilation (FGM) also referred to as female circumcision or female genital cutting is no longer restricted to Africa, the Middle East, and Asia. The European Parliament estimates that up to half a million women living in the EU have been subjected to FGM, with a further 180,000 at risk. Aware of the limited success of campaigns addressing FGM, the World Health Organization recommended a behavioural change approach be implemented in order to end FGM. To date, however, little progress has been made in adopting a behaviour change approach in strategies aimed at ending FGM. Based on research undertaken as part of the EU’s Daphne III programme, which researched FGM intervention programmes linked to African communities in the EU (REPLACE), this paper argues that behaviour change has not been implemented due to a lack of understanding relating to the application of the two broad categories of behaviour change approach: individualistic decision-theoretic and community-change game-theoretic approaches, and how they may be integrated to aid our understanding and the development of future intervention strategies. We therefore discuss how these can be integrated and implemented using community-based participatory action research methods with affected communities

    Health Benefits of Urban Agriculture

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    Health professionals increasingly recognize the value of farm-and garden-scale urban agriculture. Growing food and non-food crops in and near cities contributes to healthy communities by engaging residents in work and recreation that improves individual and public well-being. This article outlines the benefits of urban agriculture with regard to nutrition, food security, exercise, mental health, and social and physical urban environments. Potential risks are reviewed. Practical recommendations for health professionals to increase the positive benefits of urban agriculture are provided

    Synechococcus distribution and abundance in the San Juan Archipelago, Salish Sea

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    Synechococcus, a unicellular cyanobacterium of about one micron in size, is one of the most prolific and abundant primary producers worldwide and, hence, has an important role in the phytoplankton community. This study sought to determine 1) the distribution and abundance of Synechococcus in the eastern San Juan Archipelago; 2) the environmental variables related most closely to abundance; and 3) the key grazers of Synechococcus in this ecosystem. Two stations were chosen, East Sound near Orcas Island, WA and Rosario Strait near Lopez Pass, for their differing hydrographic conditions. Sampling was conducted from June to September 2012. Water samples were taken at three depths at both stations twice a month June through August, and then approximately every three days for three weeks in September. A CTD (Conductivity, Temperature, and Depth) was lowered at each station to obtain environmental data from the water column. Water samples were used for nutrient analysis, size-fractionated chlorophyll a analysis, and for the enumeration of Synechococcus and the protist grazer community. Synechococcus abundance rose as high as 1.5 x 104 cells ml-1 at both East Sound and Rosario Strait in August. Synechococcus abundance and depth distribution were nearly the same at both stations despite the well-mixed environment at Rosario and the more frequently stratified environment at East Sound. Both stations were abundant in nitrate+nitrite and phosphate throughout the sampling period. However, chlorophyll a concentrations were unusually low July through August, a season that usually exhibits variable and episodically high concentrations. Of all the environmental variables analyzed, only salinity was correlated with Synechococcus abundance at both stations, and that correlation was negative. The importance of salinity as a predictor of abundance may be due to a physiological effect of fresher water that allows for increased biomass production, or simply to the dominant effect of salinity on water column stratification, which may provide a preferable growth environment for Synechococcus. Ciliates, heterotrophic nanoflagellates, and dinoflagellates were observed with ingested Synechococcus. Surprisingly, nanoflagellates were rarely observed with ingested cells. Dinoflagellates seemed to be the key grazers of Synechococcus in the eastern San Juan Archipelago, but there was no clear temporal pattern to the level of Synechococcus ingestion by any of the aforementioned grazers

    Mystery, Imagination, and the Catholic University

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    Methadone and Corrected QT Prolongation in Pain and Palliative Care Patients: A Case–Control Study

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    Background: Methadone (ME) is commonly used in pain and palliative care (PPC) patients with refractory pain or intolerable opioid adverse effects (AEs). A unique ME AE is its corrected QT (QTc) interval prolongation risk, but most evidence exists in methadone maintenance therapy patients. Objective: Our goal was to identify QTc interval prolongation risk factors in PPC patients receiving ME and other medications known to prolong the QTc interval and develop a risk stratification tool. Design: We performed a case–control study of adult inpatients receiving ME for pain management. Settings/Subjects: Adult inpatients receiving ME with a QTc \u3e470 msec (males) and \u3e480 msec (females) were matched 1:2 according to age, history of QTc prolongation, and gender with ME patients who did not have a prolonged QTc interval. QTc prolongation risk factors were collected for both groups. Covariates were analyzed using conditional logistic regression. Classification and regression tree analysis was used to identify the ME dose associated with QTc prolongation. Results: Predictors of QTc prolongation included congestive heart failure (CHF) (OR: 11.9; 95% CI: 3.7–38.2; p \u3c 0.00), peptic ulcer disease (PUD) (odds ratio [OR]: 8.3; 95% confidence interval [95% CI]: 2.4–28.9; p \u3c 0.00), hypokalemia (OR: 6.5; 95% CI: 1.5–28.2; p \u3c 0.01), rheumatologic diseases (OR: 4.7; 95% CI: 1.6–13.9; p \u3c 0.00), taking medications with a known torsades de pointes (TdP) risk (OR: 4.4; 95% CI: 1.8–10.7; p \u3c 0.01), malignancy (OR: 3.3; 95% CI: 1.2–9.3; p \u3c 0.03), hypocalcemia (OR: 2.1; 95% CI: 0.9–4.8; p \u3c 0.07), and ME doses \u3e45 mg per day (OR: 1.9; 95% CI: 0.8–4.8; p \u3c 0.16). Mild liver disease was protective against QTc prolongation (OR: 0.05; 95% CI: 0.0–0.46; p \u3c 0.01). Conclusions: Predictors of QTc prolongation in our multivariate conditional logistic regression model included CHF, PUD, hypokalemia, rheumatologic disorders, use of medications with a known TdP risk, malignancy, hypocalcemia, and ME doses \u3e45 mg per day
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