41 research outputs found

    Effect of lactation stage and concurrent pregnancy on milk composition in the bottlenose dolphin

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    Although many toothed whales (Cetacea: Odontoceti) lactate for 2ā€“3 years or more, it is not known whether milk composition is affected by lactation stage in any odontocete species. We collected 64 pooled milk samples spanning 1ā€“30 months postpartum from three captive bottlenose dolphins Tursiops truncatus. Milks were assayed for water, fat, crude protein (TN Ɨ 6.38) and sugar; gross energy was calculated. Ovulation and pregnancy were determined via monitoring of milk progesterone. Based on analysis of changes in milk composition for each individual dolphin, there were significant increases (P<0.05) in fat (in all three dolphins) and crude protein (in two of three), and a decrease (P<0.05) in water (in two of three) over the course of lactation, but the sugar content did not change. In all three animals, the energy content was positively correlated with month of lactation, but the percentage of energy provided by crude protein declined slightly but significantly (P<0.05). At mid-lactation (7ā€“12 months postpartum, n=17), milk averaged 73.0Ā±1.0% water, 12.8Ā±1.0% fat, 8.9Ā±0.5% crude protein, 1.0Ā±0.1% sugar, 1.76Ā±0.09 kcal gāˆ’1 (=7.25 kJ gāˆ’1) and 30.3Ā±1.3% protein:energy per cent. This protein:energy per cent was surprisingly high compared with other cetaceans and in relation to the growth rates of calves. Milk progesterone indicated that dolphins ovulated and conceived between 413 and 673 days postpartum, following an increase in milk energy density. The significance of these observed compositional changes to calf nutrition will depend on the amounts of milk produced at different stages of lactation, and how milk composition and yield are influenced by sampling procedure, maternal diet and maternal condition, none of which are known

    Hypoxic Pulmonary Vasoconstriction in Humans:Tale or Myth

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    Hypoxic Pulmonary vasoconstriction (HPV) describes the physiological adaptive process of lungs to preserves systemic oxygenation. It has clinical implications in the development of pulmonary hypertension which impacts on outcomes of patients undergoing cardiothoracic surgery. This review examines both acute and chronic hypoxic vasoconstriction focusing on the distinct clinical implications and highlights the role of calcium and mitochondria in acute versus the role of reactive oxygen species and Rho GTPases in chronic HPV. Furthermore it identifies gaps of knowledge and need for further research in humans to clearly define this phenomenon and the underlying mechanism

    The new product evelopment improvement motives and practices of Miles and Snow's prospectors, analysers and defenders

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    Marketing, strategic management and contingency theory suggest that different strategies require different practices. The new product development (NPD) literature, however, hardly addresses the product development practices needed to support different strategies. An analysis of eight prospectors, twenty-seven analysers and seven defenders (Miles and Snow, 1978) suggests that the NPD improvement motives and practices of these three types of strategies are less different than we expected. Our explanation for this finding is that the three strategic types are growing towards each other, forced by changes in competition and enabled by new technologies and management concepts
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