771 research outputs found

    The Spatial Product of Arveson Systems is Intrinsic

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    We prove that the spatial product of two spatial Arveson systems is independent of the choice of the reference units. This also answers the same question for the minimal dilation the Powers sum of two spatial CP-semigroups: It is independent up to cocycle conjugacy

    Stubble effects on crop microclimate and crop performance in a sub-humid prairie climate

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    Non-Peer ReviewedStubble impacts crop microclimate in ways that have not been well-investigated, particularly in the context of crop establishment, growth and yield. In this study, the effects of different stubble heights on crop microclimate, biomass accumulation, and yield were investigated in the black soil , sub-humid climate of southwest Manitoba. Canola, pea, and wheat were sown across stubble treatments, comprised of cultivated wheat stubble, or stubble cut to a height of 10 or 30 cm in the spring of the cropping year. Plots were instrumented to monitor soil and canopy air temperature, near-surface soil moisture, wind speed, and reflected solar radiation during crop establishment. Results are discussed in the context of how changes in crop microclimate induced by stubble treatment affected crop performance. Tall stubble delayed day-time soil warming and night-time cooling, increased day-time canopy air temperature and decreased night-time air temperature, increased surface and sub-surface soil moisture, reduced wind speed near the soil surface, and increased crop canopy reflectance. These micro-climatic effects increased seedling emergence, vegetative biomass, but had minimal impact on final crop yield. The results suggest that maintenance of tall stubble should not result in a yield penalty, and may reduce input costs through reduced energy required in combining

    Subsystems of Fock Need Not Be Fock: Spatial CP-Semigroups

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    We show that a product subsystem of a time ordered system (that is, a product system of time ordered Fock modules), though type I, need not be isomorphic to a time ordered product system. In that way, we answer an open problem in the classification of CP-semigroups by product systems. We define spatial strongly continuous CP-semigroups on a unital C*-algebra and characterize them as those that have a Christensen-Evans generator.Comment: Revised and enlarged version, to appear in Proc. Amer. Math. So

    Irritability in Autistic Children Treated with Fenfluramine

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    Letter to the Editor in response to a report by Geller et al. The article presented preliminary results suggesting the possible usefulness of fenfluramine (a substituted phenylethylamine widely used as an appetite suppressant) in the treatment of infantile autism (July 15, 1982, issue). The rationale for the use of this agent rests on its ability to lower peripheral-blood levels of serotonin and on the observation that a substantial minority of autistic persons have elevated peripheral-blood serotonin levels. The report emphasized the preliminary nature of the results in a small sample of three young autistic boys with elevated serotonin levels

    Osseous differentiation of human fat tissue grafts: From tissue engineering to tissue differentiation

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    Conventional bone tissue engineering approaches require isolation and in vitro propagation of autologous cells, followed by seeding on a variety of scaffolds. Those protracted procedures impede the clinical applications. Here we report the transdifferentiation of human fat tissue fragments retrieved from subcutaneous fat into tissue with bone characteristics in vitro without prior cell isolation and propagation. 3D collagen-I cultures of human fat tissue were cultivated either in growth medium or in osteogenic medium (OM) with or without addition of Bone Morphogenetic Proteins (BMPs) BMP-2, BMP-7 or BMP-9. Ca2+ depositions were observed after two weeks of osteogenic induction which visibly increased when either type of BMP was added. mRNA levels of alkaline phosphatase (ALP) and osteocalcin (OCN) increased when cultured in OM alone but addition of BMP-2, BMP-7 or BMP-9 caused significantly higher expression levels of ALP and OCN. Immunofluorescent staining for OCN, osteopontin and sclerostin supported the observed real-time-PCR data. BMP-9 was the most effective osteogenic inducer in this system. Our findings reveal that tissue regeneration can be remarkably simplified by omitting prior cell isolation and propagation, therefore removing significant obstacles on the way to clinical applications of much needed regeneration treatments

    Repair of large segmental bone defects: BMP-2 gene activated muscle grafts vs. autologous bone grafting

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    Background: Common cell based strategies for the treatment of osseous defects require the isolation and expansion of autologous cells. Since this makes such approaches time-consuming and expensive, we developed a novel expedited technology creating gene activated muscle grafts. We have previously shown that large segmental bone defects in rats can be regenerated by implantation of muscle tissue fragments activated by BMP-2 gene transfer. Results: In the present study, we compared the bone healing capacities of such gene activated muscle grafts with bone isografts, mimicking autologous bone grafting, the clinical gold standard for treatment of bone defects in patients. Two of 14 male, syngeneic Fischer 344 rats used for this experiment served as donors for muscle and bone. Muscle tissue was harvested from both hind limbs and incubated with an adenoviral vector carrying the cDNA encoding BMP-2. Bone was harvested from the iliac crest and long bone epiphyses. Bone defects (5 mm) were created in the right femora of 12 rats and were filled with either BMP-2 activated muscle tissue or bone grafts. After eight weeks, femora were evaluated by radiographs, micro-computed tomography (mu CT), and biomechanical testing. In the group receiving BMP-2 activated muscle grafts as well as in the bone-grafting group, 100\% of the bone defects were healed, as documented by radiographs and mu CT-imaging. Bone volume was similar in both groups and biomechanical stability of the two groups was statistically indistinguishable. Conclusions: This study demonstrates that treatment of large bone defects by implantation of BMP-2 gene activated muscle tissue leads to similar bone volume and stability as bone isografts, mimicking autologous bone grafting

    Assembly and analysis of the genome sequence of the yeast Brettanomyces naardenensis CBS 7540

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    Brettanomyces naardenensis is a spoilage yeast with potential for biotechnological applications for production of innovative beverages with low alcohol content and high attenuation degree. Here, we present the first annotated genome of B. naardenensis CBS 7540. The genome of B. naardenensis CBS 7540 was assembled into 76 contigs, totaling 11,283,072 nucleotides. In total, 5168 protein-coding sequences were annotated. The study provides functional genome annotation, phylogenetic analysis, and discusses genetic determinants behind notable stress tolerance and biotechnological potential of B. naardenensis

    Evaluation of the chicken transcriptome by SAGE of B cells and the DT40 cell line

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    BACKGROUND: The understanding of whole genome sequences in higher eukaryotes depends to a large degree on the reliable definition of transcription units including exon/intron structures, translated open reading frames (ORFs) and flanking untranslated regions. The best currently available chicken transcript catalog is the Ensembl build based on the mappings of a relatively small number of full length cDNAs and ESTs to the genome as well as genome sequence derived in silico gene predictions. RESULTS: We use Long Serial Analysis of Gene Expression (LongSAGE) in bursal lymphocytes and the DT40 cell line to verify the quality and completeness of the annotated transcripts. 53.6% of the more than 38,000 unique SAGE tags (unitags) match to full length bursal cDNAs, the Ensembl transcript build or the genome sequence. The majority of all matching unitags show single matches to the genome, but no matches to the genome derived Ensembl transcript build. Nevertheless, most of these tags map close to the 3' boundaries of annotated Ensembl transcripts. CONCLUSIONS: These results suggests that rather few genes are missing in the current Ensembl chicken transcript build, but that the 3' ends of many transcripts may not have been accurately predicted. The tags with no match in the transcript sequences can now be used to improve gene predictions, pinpoint the genomic location of entirely missed transcripts and optimize the accuracy of gene finder software
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