527 research outputs found
You mean I have to teach sustainability too? Initial teacher education studentsâ perspectives on the sustainability cross-curriculum priority
Abstract: In this paper, we report on an investigation into initial teacher education students (ITES) understandings of sustainability and the Australian National Curriculum Sustainability Cross Curricular Priority (CCP). We also explore their willingness and capacities to embed the CCP into their own teaching practices. The ITESs (N=392) completed a quantitative survey with a series of Likert Scale questions and were asked to list â5 wordsâ when they think of sustainability. Analysis reveals that ITESs have generally limited to moderate understandings of sustainability and education for sustainability, but lesser understandings of the Sustainability CCP and the 9 organising ideas. Understandings of sustainability were dominated by an environmental focus. We conclude this paper with a discussion of the implications of narrow environmental understandings of sustainability. We explore factors that limit and enable teacher educators to embed sustainability education more explicitly. We note the importance role teacher educators play in supporting ITESs to better understand sustainability
Detection and quantification of 14 Campylobacter species in pet dogs reveals an increase in species richness in feces of diarrheic animals
<p>Abstract</p> <p>Background</p> <p>The genus <it>Campylobacter </it>includes many species, some of which are known human and animal pathogens. Even though studies have repeatedly identified domestic dogs as a risk factor for human campylobacteriosis, our understanding of <it>Campylobacter </it>ecology in this reservoir is limited. Work to date has focused primarily on a limited number of species using culture-based methods. To expand our understanding of <it>Campylobacter </it>ecology in dogs, a collection of fecal samples from 70 healthy and 65 diarrheic pet dogs were examined for the presence and levels of 14 <it>Campylobacter </it>species using quantitative PCR.</p> <p>Results</p> <p>It was found that 58% of healthy dogs and 97% of diarrheic dogs shed detectable levels of <it>Campylobacter </it>spp., with <it>C. coli, C. concisus, C. fetus, C. gracilis, C. helveticus, C. jejuni, C. lari, C. mucosalis, C. showae, C. sputorum </it>and <it>C. upsaliensis </it>levels significantly higher in the diarrheic population. Levels of individual <it>Campylobacter </it>species detected ranged from 10<sup>3 </sup>to 10<sup>8 </sup>organisms per gram of feces. In addition, many individual samples contained multiple species of <it>Campylobacter</it>, with healthy dogs carrying from 0-7 detectable species while diarrheic dogs carried from 0-12 detectable species.</p> <p>Conclusions</p> <p>These findings represent the largest number of <it>Campylobacter </it>species specifically tested for in animals and is the first report to determine quantifiable levels of <it>Campylobacter </it>being shed from dogs. This study demonstrates that domestic dogs can carry a wide range of <it>Campylobacter </it>species naturally and that there is a notable increase in species richness detectable in the diarrheic population. With several of the detected <it>Campylobacter </it>species known or emerging pathogens, these results are relevant to both ecological and public health discussions.</p
Structure of human saposin A at lysosomal pH.
The saposins are essential cofactors for the normal lysosomal degradation of complex glycosphingolipids by acid hydrolase enzymes; defects in either saposin or hydrolase function lead to severe metabolic diseases. Saposin A (SapA) activates the enzyme β-galactocerebrosidase (GALC), which catalyzes the breakdown of β-D-galactocerebroside, the principal lipid component of myelin. SapA is known to bind lipids and detergents in a pH-dependent manner; this is accompanied by a striking transition from a `closed' to an `open' conformation. However, previous structures were determined at non-lysosomal pH. This work describes a 1.8â
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resolution X-ray crystal structure determined at the physiologically relevant lysosomal pH 4.8. In the absence of lipid or detergent at pH 4.8, SapA is observeed to adopt a conformation closely resembling the previously determined `closed' conformation, showing that pH alone is not sufficient for the transition to the `open' conformation. Structural alignments reveal small conformational changes, highlighting regions of flexibility.CHH is funded by a Wellcome Trust PhD studentship, RJR is supported by a Principal Research Fellowship funded by the Wellcome Trust (Grant No. 082961/Z/07/Z) and JED is supported by a Royal Society University Research Fellowship (UF100371). The Cambridge Institute for Medical Research is supported by a Wellcome Trust Strategic Award (100140).This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1107/S2053230X1500858
Editorial: âWeighing inâ on the Framingham Osteoarthritis Study: Measuring Biomechanical and Metabolic Contributions to Osteoarthritis
Comparison of Convective Overshooting Models and Their Impact on Abundances from Integrated Light Spectroscopy of Young ( 3 Gyr) Star Clusters
As part of an ongoing program to measure detailed chemical abundances in
nearby galaxies, we use a sample of young to intermediate age clusters in the
Large Magellanic Cloud with ages of 10 Myr to 2 Gyr to evaluate the effect of
isochrone parameters, specifically core convective overshooting, on Fe
abundance results from high resolution, integrated light spectroscopy. In this
work we also obtain fiducial Fe abundances from high resolution spectroscopy of
the cluster individual member stars. We compare the Fe abundance results for
the individual stars to the results from isochrones and integrated light
spectroscopy to determine whether isochrones with convective overshooting
should be used in our integrated light analysis of young to intermediate age
(10 Myr -3 Gyr) star clusters. We find that when using the isochrones from the
Teramo group, we obtain more accurate results for young and intermediate age
clusters over the entire age range when using isochrones without convective
overshooting. While convective overshooting is not the only uncertain aspect of
stellar evolution, it is one of the most readily parametrized ingredients in
stellar evolution models, and thus important to evaluate for the specific
models used in our integrated light analysis. This work demonstrates that our
method for integrated light spectroscopy of star clusters can provide unique
tests for future constraints on stellar evolution models of young and
intermediate age clusters.Comment: 16 pages, accepted for publication in Ap
The mechanism of glycosphingolipid degradation revealed by a GALC-SapA complex structure.
Sphingolipids are essential components of cellular membranes and defects in their synthesis or degradation cause severe human diseases. The efficient degradation of sphingolipids in the lysosome requires lipid-binding saposin proteins and hydrolytic enzymes. The glycosphingolipid galactocerebroside is the primary lipid component of the myelin sheath and is degraded by the hydrolase β-galactocerebrosidase (GALC). This enzyme requires the saposin SapA for lipid processing and defects in either of these proteins causes a severe neurodegenerative disorder, Krabbe disease. Here we present the structure of a glycosphingolipid-processing complex, revealing how SapA and GALC form a heterotetramer with an open channel connecting the enzyme active site to the SapA hydrophobic cavity. This structure defines how a soluble hydrolase can cleave the polar glycosyl headgroups of these essential lipids from their hydrophobic ceramide tails. Furthermore, the molecular details of this interaction provide an illustration for how specificity of saposin binding to hydrolases is encoded
Confirmation that âBrachyspira hampsoniiâ clade I (Canadian strain 30599) causes mucohemorrhagic diarrhea and colitis in experimentally infected pigs
BACKGROUND: âBrachyspira hampsoniiâ, discovered in North America in 2010 associated with dysentery-like illness, is an economically relevant swine pathogen resulting in decreased feed efficiency and increased morbidity, mortality and medication usage. âB. hampsoniiâ clade II strain 30446 has been shown to be causally associated with mucohemorrhagic diarrhea and colitis. Our objectives were to determine if âBrachyspira hampsoniiâ clade I strain 30599 is pathogenic to pigs, and to evaluate the relative diagnostic performance of three ante mortem sampling methodologies (direct PCR on feces, PCR on rectal GenoTube Livestock swabs, Brachyspira culture from rectal swabs). Five-week old pigs were intragastrically inoculated thrice with 10(8) genomic equivalents "B. hampsonii" (nâ=â12), or served as sham controls (nâ=â6). Feces were sampled and consistency assessed daily. Necropsies were performed 24Â h after peak clinical signs. RESULTS: One pig died due to unrelated illness. Nine of 11 inoculated pigs, but no controls, developed mucoid or mucohemorrhagic diarrhea (MHD). Characteristic lesions of swine dysentery were observed in large intestine. âB. hampsoniiâ strain 30599 DNA was detected by qPCR in feces of all inoculated pigs for up to 6Â days prior to the onset of MHD. The organism was isolated from the feces and colons of pigs demonstrating MHD, but not from controls. B. intermedia was isolated from inoculated pigs without MHD, and from 5 of 6 controls. CONCLUSIONS: We conclude that âBrachyspira hampsoniiâ clade I strain 30599 is pathogenic and causes mucohemorrhagic diarrhea and colitis in susceptible pigs. Moreover, the three sampling methodologies performed similarly. GenoTube Livestock, a forensic swab designed to preserve DNA during shipping is a useful tool especially in settings where timely transport of diagnostic samples is challenging
Gardnerella vaginalis subgroups defined by cpn60 sequencing and sialidase activity in isolates from Canada, Belgium and Kenya
Increased abundance of Gardnerella vaginalis and sialidase activity in vaginal fluid is associated with bacterial vaginosis (BV), a common but poorly understood clinical entity associated with poor reproductive health outcomes. Since most women are colonized with G. vaginalis, its status as a normal member of the vaginal microbiota or pathogen causing BV remains controversial, and numerous classification schemes have been described. Since 2005, sequencing of the chaperonin-60 universal target (cpn60 UT) has distinguished four subgroups in isolate collections, clone libraries and deep sequencing datasets. To clarify potential clinical and diagnostic significance of cpn60 subgroups, we undertook phenotypic and molecular characterization of 112 G. vaginalis isolates from three continents. A total of 36 subgroup A, 33 B, 35 C and 8 D isolates were identified through phylogenetic analysis of cpn60 sequences as corresponding to four "clades" identified in a recently published study, based on sequencing 473 genes across 17 isolates. cpn60 subgroups were compared with other previously described molecular methods for classification of Gardnerella subgroups, including amplified ribosomal DNA restriction analysis (ARDRA) and real-time PCR assays designed to quantify subgroups in vaginal samples. Although two ARDRA patterns were observed in isolates, each was observed in three cpn60 subgroups (A/B/D and B/C/D). Real-time PCR assays corroborated cpn60 subgroups overall, but 13 isolates from subgroups A, B and D were negative in all assays. A putative sialidase gene was detected in all subgroup B, C and D isolates, but only in a single subgroup A isolate. In contrast, sialidase activity was observed in all subgroup B isolates, 3 (9%) subgroup C isolates and no subgroup A or D isolates. These observations suggest distinct roles for G. vaginalis subgroups in BV pathogenesis. We conclude that cpn60 UT sequencing is a robust approach for defining G. vaginalis subgroups within the vaginal microbiome
Detection of European Strain of \u3ci\u3eEchinococcus multilocularis\u3c/i\u3e in North America
To the Editor: In 2009, an alveolar hydatid cyst, the intermediate stage of the cestode Echinococcus multilocularis, was detected in the liver of a dog from Quesnel, British Columbia (BC), Canada, 600 km west of the nearest known record of this parasite in central North America. Alveolar hydatid cysts normally occur in rodent intermediate hosts. However, humans can serve as aberrant intermediate hosts; cysts generally originate in the liver and, in about one third of cases, metastasize throughout the body. Detection of the larval stage of this pathogen in an unusual host in a new geographic region required application of multiple molecular epidemiologic techniques to determine if this was range expansion of a native strain or introduction of a new strain of veterinary and public health concern.
The possible establishment of a European strain in North American wildlife, with spillover into domestic dogs, may have implications for public health and require increased vigilance by medical and veterinary personnel in the newly endemic region. Compared with native North American strains, European strains of E. multilocularis appear to have greater potential to cause alveolar hydatid disease (AHD) in humans. These strains are emerging worldwide (increasing in both prevalence and distribution) as a result of changes in landscape, climate, and wildlifeâhuman interfaces. In Europe, human AHD can be fatal (definite or probable cause of death in 23.5% of 119 recent cases) and has low cure rates (5% of 408 recent cases). As of 2000, in Europe and Asia, the estimated cost per case of AHD was US 300,000. Therefore, better understanding of the distribution, genetic diversity, and pathogenicity of strains of E. multilocularis is needed to assess risks and mitigate costs for public and veterinary health, as well as to provide evidence for the regulation and screening of imported domestic animals and translocated wildlife
Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. III. The Large Magellanic Cloud: Fe and Ages
In this paper we refine our method for the abundance analysis of high
resolution spectroscopy of the integrated light of unresolved globular clusters
(GCs). This method was previously demonstrated for the analysis of old (10
Gyr) Milky Way GCs. Here we extend the technique to young clusters using a
training set of 9 GCs in the Large Magellanic Cloud (LMC). Depending on the
signal-to-noise ratio of the data, we use 20-100 Fe lines per cluster to
successfully constrain the ages of old clusters to within a 5 Gyr range,
the ages of 2 Gyr clusters to a 1-2 Gyr range, and the ages of the
youngest clusters (0.05-1 Gyr) to a 200 Myr range. We also demonstrate
that we can measure [Fe/H] in clusters with any age less than 12 Gyrs with
similar or only slightly larger uncertainties (0.1-0.25 dex) than those
obtained for old Milky Way GCs (0.1 dex); the slightly larger uncertainties are
due to the rapid evolution in stellar populations at these ages. In this paper,
we present only Fe abundances and ages. In the next paper in this series, we
present our complete analysis of the elements for which we are able
to measure abundances. For several of the clusters in this sample, there are no
high resolution abundances in the literature from individual member stars; our
results are the first detailed chemical abundances available. The spectra used
in this paper were obtained at Las Campanas with the echelle on the du Pont
Telescope and with the MIKE spectrograph on the Magellan Clay Telescope.Comment: 34 pages, accepted for publication in Ap
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