736 research outputs found
The effect of prolonged cold storage of eland (Taurotragus oryx) cauda epididymides on the spermatozoa: possible implications for the conservation of biodiversity
The objectives of this study were to investigate the effects of prolonged storage of cauda epididymides at 4 °C on spermatozoa, and to determine the practicality of utilising epididymal sperm, harvested from testes collected during routine culling of game animals, in assisted reproductive technologies. Testes from eland (Taurotragus oryx) were collected and epididymides removed and maintained at 4 °C. Sperm motility, viability, morphology and membrane integrity were examined at 12 h intervals for 108 h. Sperm motility and viability were significantly lower at the end of the experiment than at the start (P < 0.05) and there was individual variation in the rate at which motility and viability declined. The total number of normal sperm decreased significantly with prolonged storage at 4 °C. Midpiece defects were the most common and head and tail abnormalities were rare. A significant decrease in acrosomal and nuclear membrane integrity was observed with prolonged cold storage but there was no significant change in cell membrane integrity. However, about 30% of epididymal sperm survived for 3 days at 4 °C and more than 10% survived for 4 days, and it should be possible to use sperm from culled animals in some assisted reproductive technologies
DBT, FAP, and ACT: How empirically oriented are the new behavior therapy technologies?
Empirically validated methods for reducing stigma and prejudice toward recipients of behavioral healthcare services are badly needed. In the present study, two packages presented in one day workshops were compared to a biologically oriented Educational Control condition in the alleviation of stigmatizing attitudes in drug abuse counselors. One, Acceptance and Commitment Training (ACT), utilized acceptance, defusion, mindfulness, and values methods. The other, Multicultural Training, sensitized participants to group prejudices and biases. Measures of stigma and burnout were taken pre-training, post-training, and after a three month follow-up. Results showed that Multicultural Training had an impact on stigmatizing attitudes and burnout post-intervention but not at follow-up, but showed better gains in a sense of personal accomplishment as compared to the Educational Control at follow-up. ACT had a positive impact on stigma at follow-up and on burnout at post-treatment and follow-up and follow-up gains in burnout exceeded those of Multicultural Training. ACT also significantly changed the believability of stigmatizing attitudes. This process mediated the impact of ACT but not Multicultural Training on follow-up stigma and burnout. This preliminary study opens new avenues for reducing stigma and burnout in behavioral health counselors
Impact of phytoplankton community size on a linked global ocean optical and ecosystem model
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 89 (2012): 61-75, doi:10.1016/j.jmarsys.2011.08.002.We isolated the effect phytoplankton cell size has on varying remote sensing reflectance
spectra (Rrs(λ)) in the presence of optically active constituents by using optical and radiative
transfer models linked in an offline diagnostic calculation to a global
biogeochemical/ecosystem/circulation model with explicit phytoplankton size classes. Two case
studies were carried out, each with several scenarios to isolate the effects of chlorophyll
concentration, phytoplankton cell size, and size-varying phytoplankton absorption on Rrs(λ).
The goal of the study was to determine the relative contribution of phytoplankton cell size and chlorophyll to overall Rrs(λ) and to understand where a standard band ratio algorithm (OC4) may
under/overestimate chlorophyll due to Rrs(λ) being significantly affected by phytoplankton size.
Phytoplankton cell size was found to contribute secondarily to Rrs(λ) variability and to amplify
or dampen the seasonal cycle in Rrs(λ), driven by chlorophyll. Size and chlorophyll were found
to change in phase at low to mid-latitudes, but were anti-correlated or poorly correlated at high
latitudes. Phytoplankton size effects increased model calculated Rrs(443) in the subtropical ocean during local spring through early fall months in both hemispheres and decreased Rrs(443)
in the Northern Hemisphere high latitude regions during local summer to fall months. This study
attempts to tease apart when/where variability about the OC4 relationship may be associated
with cell size variability. The OC4 algorithm may underestimate [Chl] when the fraction of
microplankton is elevated, which occurs in the model simulations during local spring/summer
months at high latitudes in both hemispheres.Funding for this study came from a NASA Earth and Space Science Fellowship and
University of Rhode Island Graduate School Oceanography Alumni Fellowship, both awarded to
C. Mouw. The CCSM-3 BEC simulations were generated with support from NASA Ocean
Biology and Biogeochemistry Program (NNX07AL80G) and the NSF Center for Microbial
Oceanography Research and Education (C-MORE, EF-0424599)
Impact of Atmospheric Correction on Classification and Quantification of Seagrass Density from WorldView-2 Imagery
Mapping the seagrass distribution and density in the underwater landscape can improve global Blue Carbon estimates. However, atmospheric absorption and scattering introduce errors in space-based sensors’ retrieval of sea surface reflectance, affecting seagrass presence, density, and above-ground carbon (AGCseagrass) estimates. This study assessed atmospheric correction’s impact on mapping seagrass using WorldView-2 satellite imagery from Saint Joseph Bay, Saint George Sound, and Keaton Beach in Florida, USA. Coincident in situ measurements of water-leaving radiance (Lw), optical properties, and seagrass leaf area index (LAI) were collected. Seagrass classification and the retrieval of LAI were compared after empirical line height (ELH) and dark-object subtraction (DOS) methods were used for atmospheric correction. DOS left residual brightness in the blue and green bands but had minimal impact on the seagrass classification accuracy. However, the brighter reflectance values reduced LAI retrievals by up to 50% compared to ELH-corrected images and ground-based observations. This study offers a potential correction for LAI underestimation due to incomplete atmospheric correction, enhancing the retrieval of seagrass density and above-ground Blue Carbon from WorldView-2 imagery without in situ observations for accurate atmospheric interference correction
Multifunctional Biocomposites Based on Polyhydroxyalkanoate and Graphene/Carbon Nanofiber Hybrids for Electrical and Thermal Applications
Most polymers are long-lasting and produced from monomers derived from fossil
fuel sources. Bio-based and/or biodegradable plastics have been proposed as a
sustainable alternative. Amongst those available, polyhydroxyalkanoate (PHA)
shows great potential across a large variety of applications but is currently
limited to packaging, cosmetics and tissue engineering due to its relatively
poor physical properties. An expansion of its uses can be accomplished by
developing nanocomposites where PHAs are used as the polymer matrix. Herein, a
PHA biopolyester was melt blended with graphene nanoplatelets (GNPs) or with a
1:1 hybrid mixture of GNPs and carbon nanofibers (CNFs). The resulting
nanocomposites exhibited enhanced thermal stability while their Young's modulus
roughly doubled compared to pure PHA. The hybrid nanocomposites percolated
electrically at lower nanofiller loadings compared to the GNP-PHA system. The
electrical conductivity at 15 wt.% loading was ~ 6 times higher than the
GNP-based sample. As a result, the electromagnetic interference shielding
performance of the hybrid material was around 50% better than the pure GNPs
nanocomposites, exhibiting shielding effectiveness above 20 dB, which is the
threshold for common commercial applications. The thermal conductivity
increased significantly for both types of bio-nanocomposites and reached values
around 5 W K-1 m-1 with the hybrid-based material displaying the best
performance. Considering the solvent-free and industrially compatible
production method, the proposed multifunctional materials are promising to
expand the range of application of PHAs and increase the environmental
sustainability of the plastic and plastic electronics industry.Comment: 26 page
The transparent failure of norms to keep up standards of belief
We argue that the most plausible characterisation of the norm of truth—it is permissible to believe that p if and only if p is true—is unable to explain Transparency in doxastic deliberation, a task for which it is claimed to be equipped. In addition, the failure of the norm to do this work undermines the most plausible account of how the norm guides belief formation at all. Those attracted to normativism about belief for its perceived explanatory credentials had better look elsewhere
Isolated Meningeal Recurrence of Transitional Cell Carcinoma of the Bladder
Meningeal carcinomatosis occurs in 1–18% of patients with solid tumours, most commonly carcinomas of the breast and lung or melanomas. There are relatively few reports of meningeal carcinomatosis in transitional cell carcinoma of the bladder. Isolated meningeal recurrence is particularly uncommon, and we present an unusual case of this in a 58-year-old man. The case was further complicated by the somewhat atypical presentation with a confirmed ischaemic stroke. The patient died one month after presentation
The reintroduction of large carnivores to the Eastern Cape, South Africa: an assessment
Recently, conservation estate in South Africa's Eastern Cape Province has increased 10-fold resulting in large predators being increasingly reintroduced to restore ecological integrity and maximize tourism. We describe the reintroductions of large carnivores (>10 kg) that have occurred in the Eastern Cape and use various criteria to assess their success. Lion Panthera leo reintroduction has been highly successful with a population of 56 currently extant in the region and problems of overpopulation arising. The African wild dog Lycaon pictus population has increased to 24 from a founder population of 11. Preliminary results for spotted hyaenas Crocuta crocuta also indicate success. Wild populations of leopards Panthera pardus exist on several reserves and have been supplemented by translocated individuals, although deaths of known individuals have occurred and no estimate of reproduction is available. Cheetah Acinonyx jubatus reintroduction has also been less successful with 36 individuals reintroduced and 23 cubs being born but only 41 individuals surviving in 2005. Criteria for assessing the success of reintroductions of species that naturally occur in low densities, such as top predators, generally have limited value. Carrying capacity for large predators is unknown and continued monitoring and intensive management will be necessary in enclosed, and possibly all, conservation areas in the Eastern Cape to ensure conservation success
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