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Indian Ocean humpback dolphins Sousa plumbea inhabit nearshore waters from South Africa to eastern India. Humpback dolphins are vulnerable to conservation threats due to their naturally small population sizes and use of nearshore habitats, where human activities are highest. We investigated the abundance and residency of this species inhabiting Mossel Bay, South Africa, using photographic mark-recapture. Data were collected during 81 surveys in Mossel Bay between 2011 and 2013. Open population modelling using the POPAN parameterisation produced a ‘super-population’ estimate of 125 individuals (95% CI: 61–260) and within-year estimates of between 33 and 86 individuals (2011: 71 [95% CI: 30–168]; 2012: 33 [15–73], 32 [15–70]; 2013: 46 [20–108]). Although less appropriate, closed capture models were also run for comparison with previous studies in the region and generated similar, but slightly smaller, population estimates within each year. We compared our catalogue with opportunistic data collected from East London, Plettenberg Bay, De Hoop and Gansbaai. The only catalogue matches attained were between Plettenberg Bay (n = 44 identified) and Mossel Bay (n = 67 identified), separated by 140?km. Population exchange was moderate, with nine individuals resighted in multiple years between these two areas. This study supports previous findings of long-range movements for this species and provides a baseline from which to assess future impacts on the population. 相似文献
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Krahn MM Hanson MB Baird RW Boyer RH Burrows DG Emmons CK Ford JK Jones LL Noren DP Ross PS Schorr GS Collier TK 《Marine pollution bulletin》2007,54(12):1903-1911
“Southern Resident” killer whales include three “pods” (J, K and L) that reside primarily in Puget Sound/Georgia Basin during the spring, summer and fall. This population was listed as “endangered” in the US and Canada following a 20% decline between 1996 and 2001. The current study, using blubber/epidermis biopsy samples, contributes contemporary information about potential factors (i.e., levels of pollutants or changes in diet) that could adversely affect Southern Residents. Carbon and nitrogen stable isotopes indicated J- and L-pod consumed prey from similar trophic levels in 2004/2006 and also showed no evidence for a large shift in the trophic level of prey consumed by L-pod between 1996 and 2004/2006. ∑PCBs decreased for Southern Residents biopsied in 2004/2006 compared to 1993–1995. Surprisingly, however, a three-year-old male whale (J39) had the highest concentrations of ∑PBDEs, ∑HCHs and HCB. POP ratio differences between J- and L-pod suggested that they occupy different ranges in winter. 相似文献
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L.?C.?G?tzeEmail author R.?Abart R.?Milke S.?Schorr I.?Zizak R.?Dohmen R.?Wirth 《Physics and Chemistry of Minerals》2014,41(9):681-693
Polycrystalline spinel layers were grown experimentally at the contacts between single-crystal corundum substrates and initially amorphous, then polycrystalline MgO thin films. The growth behavior of the spinel layers was monitored in situ using synchrotron X-ray diffraction. The change in the integrated intensity of the 111 spinel Bragg peak was correlated with the thickness of the layer as determined from ex situ TEM characterization of the run products. At \(900\,^{\circ }\hbox {C},\) a transition from linear growth, corresponding to interface reaction control, to parabolic growth, corresponding to diffusion control, occurred at a layer thickness of less than 10 nm. At 1,000 \(^{\circ }\hbox {C},\) growth was largely linear up to a layer thickness in excess of 300 nm. A thermodynamic model was applied to extract the kinetic parameters characterizing interface motion and long-range diffusion from this growth behavior. 相似文献
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N. Santillán Soto O.R. García Cueto S. Ojeda Benítez N. Velázquez Limón M. Quintero Núñez M. Schorr 《Atmósfera》2013,26(4):499-507
Solar radiation is one of the most important energy resources of our planet. The interest in its use as a renewable and clean energy to mitigate the greenhouse gases (GHG) effects has increased significantly. This paper evaluates the measurements of global solar radiation and its energy potential and presents a comparison between both of them, as an example of the effort to reduce GHG emissions. The measurements were made with pyranometers installed in the city of Mexicali, Baja California, located in northwestern Mexico, and the city of Yuma, Arizona, located in the southwestern United States. Separated by a distance of 96 km, both cities have a sustained development and are climatically similar, since they present numerous sunny days, extreme hot temperatures and little precipitation. The results presented show differences in their behavior and in the solar radiation measurement values, especially for the critical spring and summer seasons, with values 15.73% (0.042 kW/m2) higher in Mexicali with respect to Yuma. Energy power is estimated, and it is discussed with some variables as global solar radiation, rainfall, air temperature, relative humidity and climatology of clear, partly cloudy, and cloudy days. With this estimation, the solar energy used and GHG avoided is projected for Mexicali. It is assessed that 291 tons of GHG are prevented. The Mexicali values of potential energy are higher than those of Yuma; therefore, this solar and energy comparative study provides reasons to develop these technologies in Mexico, but solar technologies should be deployed also in Yuma. The measured data at the regional level demonstrate their importance, and the relevance of the proposed mitigation strategy for climate change. 相似文献
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