100 research outputs found
Pneumocystis Murina Infection in Immunodeficient Mice in a Closed Barrier Unit: a Case Report
Pneumocystis is an important pathogen in immunocompromised individuals. In colonies of immunodeficient mice, P. murina can cause wasting disease and make the breeding and maintenance of immunodeficient animals difficult, unless they are continuously treated with sulfadiazin/trimethoprim. At University of Aarhus immunodeficient and immunocompetent mice were co-housed in a barrier unit. The facility was closed for entrance of animals (except for embryos for embryo transfer) and the entrance for personnel was highly restricted. The breeding performance of immunodeficient animals was comparable to that of the immunocompetent mice for a period of more than 3 years, until wasting disease and decreased litter size specifically in the breeding colony of immunodeficient mice occurred. Clinical symptoms of affected mice included laboured breathing, hunched up position, unwillingness to move, and ruffled coat. Pneumocystis infection was confirmed by histological examination and PCR. The partial sequence of the mitochondrial large subunit rRNA gene obtained (GenBank accession no AF548626) displayed 99 % identity to that of Pneumocystis murina (formerly Pneumocystis carinii f.sp.muris) found in laboratory mice. The immunodeficient animals were removed from the barrier and treated with sulfadiazin/trimethoprim in a separate unit. After the removal of immunodeficient animals, Pneumocystis could not be detected by PCR in the remaining animals. Our data add to the growing evidence that immunocompetent animals harboring Pneumocystis as a subclinical infection may be reservoirs for this organism. Still it remains to be determined how the infection was introduced and whether a latent infection can persist or the outbreak was caused by leakage in the barrier.
Stratigraphy, structure and metamorphism of Archean rocks at Rainy Lake, Ontario
The rocks of the Rainy Lake area have been deformed
during three distinctive episodes. Minor structures provide
the geometry which characterizes each episode. The youngest
structures include regional faults, a crenulation cleavage,
kink bands and minor F[subscript 3] folds. These D[subscript 3] structures are superimposed on structures of the D[subscript 2] episode. These include dominant F[subscript 2] folds having axes lying in a penetrative cleavage which parallels the axial surfaces of the folds. Some F[subscript 2]
folds have a downward structural facing which is evidence that the stratigraphic succession at Rainy Lake is overturned
at a regional scale. It is proposed that this inversion took
place during a D[subscript 1] deformation by the formation of large F[subscript1] fold nappes. Minor D[subscript1] structures are difficult to document.
The rocks of the region were metamorphosed simultaneously
with much of the deformation. The distribution of
index minerals defines the boundaries of the biotite,
staurolite-cordierite and sillimanite-muscovite zones. The
non-parallel distribution of metamorphic minerals may be
explained by the non-parallelism of isotherms and isobars
during medium grade metamorphism.
These new data support the view that the Coutchiching
biotite schists at Rainy Lake are stratigraphically
younger than metavolcanic rocks of the Keewatin Group although
they presently underlie the Keewatin structurally. This
observation resolves a part of the historically important
”Seine-Coutchiching problem”
Det ubevidste i objektrelationsteorien
The article contains an account of the fate that the concept of the unconscious has undergone in the theories of Melanie Klein and D.W. Winnicott. On the basis of a statement of aspects of Freud's conception of the unconscious, an account of the Kleiniancomprehension of unconscious phantasies and their roles in the subject's internal world is given. Furthermore we present some theoretical problems related to the concept of internal objects. Finally we discuss the position of the unconscious in Winnicott'stheory. Here it is argued that Winnicott's focus of interest moves to the intermediate area between internal world and external reality. In this context we expound the essential splitting in the True and the False Self and the relation of these concepts to the Freudian formulations of the psychical apparatus.Artiklen rummer en fremstilling af den skæbne, begrebet det ubevidste har undergået i Melanie Kleins og D. W. Winnicotts teorier.På basis af en redegørelse for aspekter af Freuds tænkning om det ubevidste beskrives den kleinianske forståelse af ubevidste fantasier og deres rolle i subjektets indre verden. Der gives desuden en redegørelse for teoretiske problemer i forbindelse med begrebet om indre objekter. Endelig diskuteres begrebet det ubevidstes status i Winnicotts teori. Her argumenteres for, at Winnicotts interessefokus flyttes til det mellemliggende område mellem indre verden og ydre realitet. I denne sammenhæng redegøres for den centrale spaltning i det sande og falske selv og begrebernes relation til Freuds opdelinger af det psykiske apparat
Comparable early-stage decomposition but contrasting underlying drivers between surface and cave habitats along an elevational gradient
Decomposition is a major contributor to ecosystem respiration, determining the carbon emission and nutrient cycling rates. Our current understanding of decomposition dynamics and their underlying drivers has mainly focused on surface habitats but largely ignored in subterranean environments. Here we studied abiotic and microbial drivers of early-stage litter decomposition inside and outside caves along an elevational gradient in Tenerife. We found comparable decomposition rates (k) and litter stabilizing factors (S), with contrasting drivers and elevational variation. At the surface, we observed a mid-elevational trend in k, which tended to correlate with water availability, cooler temperatures, nutrient availability, and surface-specific bacterial taxa. In sharp contrast, caves showed no elevational impact nor influence of abiotic parameters and bacterial communities on k. Despite this, we found higher levels of S in caves, which were associated mainly with reduced water availability, lower temperatures and cave-specific bacterial taxa, indicating that conditions in caves are strongly linked with carbon storage. Our findings imply that our current perception of terrestrial habitat-based carbon cycling are underestimating the net carbon budget in areas with caves. Disentangling the role of the environment on decomposition in caves is key to fully characterize their roles in nutrient cycling and to understand how increasing anthropogenic pressures will affect fundamental processes in subterranean ecosystems.info:eu-repo/semantics/publishedVersio
Nutrient-limited subarctic caves harbour more diverse and complex bacterial communities than their surface soil
Background: Subarctic regions are particularly vulnerable to climate change, yet little is known about nutrient
availability and biodiversity of their cave ecosystems. Such knowledge is crucial for predicting the vulnerability of
these ecosystems to consequences of climate change. Thus, to improve our understanding of life in these habitats,
we characterized environmental variables, as well as bacterial and invertebrate communities of six subarctic caves in
Northern Norway.
Results: Only a minuscule diversity of surface-adapted invertebrates were found in these caves. However, the bacte‑
rial communities in caves were compositionally diferent, more diverse and more complex than the nutrient-richer
surface soil. Cave soil microbiomes were less variable between caves than between surface communities in the same
area, suggesting that the stable cave environments with tougher conditions drive the uniform microbial communi‑
ties. We also observed only a small proportion of cave bacterial genera originating from the surface, indicating unique
cave-adapted microbial communities. Increased diversity within caves may stem from higher niche specialization and
levels of interdependencies for nutrient cycling among bacterial taxa in these oligotrophic environments.
Conclusions: Taken together this suggest that environmental changes, e.g., faster melting of snow as a result of
global warming that could alter nutrient infux, can have a detrimental impact on interactions and dependencies of
these complex communities. This comparative exploration of cave and surface microbiomes also lays the founda‑
tion to further investigate the long-term environmental variables that shape the biodiversity of these vulnerable
ecosystems.info:eu-repo/semantics/publishedVersio
- …