104 research outputs found

    Weeds on hard surfaces in Saxony and efficacy of thermic weed control

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    In den Jahren 2006 bis 2008 fanden Unkrautaufnahmen auf 52 Wegen und Plätzen in Chemnitz und Umgebung statt. Mehr als 70 Unkrautarten wurden festgestellt. Domi­nierende Arten waren Poa annua L. und Taraxacum offici­nale Wiggers. Sie traten auf mehr als 90% der Flächen auf. Laubmoose und Plantago major L. erreichten Stetigkeiten um 80%. Auf fast 70% der Flächen wurde Solidago canadensis L. gefunden, ein Neophyt. Poa annua erreichte den höchsten mittleren Deckungsgrad. Hohe Deckungsgrade wurden auch bei Laubmoosen und Taraxacum officinale festgestellt. Von 2006 bis 2010 wurden auf Wegen und Plätzen in Chemnitz Untersuchungen zur Wirkung von drei thermischen Bekämpfungsverfahren gegen Unkräuter durchgeführt. Folgende Verfahren wurden untersucht: 1.Heißschaumverfahren „Waipuna“ in den Jahren 2006 und 2007, insgesamt 9 Flächen, zwei Anwendungen pro Jahr; 2.Heißdampfverfahren „OMK“ im Jahr 2008, 11 Flächen, drei bis vier Anwendungen pro Jahr; 3.Heißwasser-Heißdampfverfahren „Geysir“ in den Jahren 2009 und 2010, insgesamt 10 Flächen, drei bis vier Anwendungen pro Jahr. Die drei Verfahren wirkten meist gut gegen einjährige Unkräuter und Moose. Sie waren nicht ausreichend wirksam gegen Taraxacum officinale. Keines der drei Verfahren bekämpfte die Unkräuter vollständig mit der oben genannten Anzahl von Anwendungen. Bei mehrjähriger Anwendung des Heißwasser-Heißdampfverfahrens „Geysir“ konnte der Unkrautbesatz auf den Flächen verringert werden.    During the years 2006 to 2008 a research of weed occu­rence on footpaths and places was carried out in the city of Chemnitz and in the surrounding area. More than 70 weed species were found. Dominant species were Poa annua L. and Taraxacum officinale Wiggers. They were found on more than 90  of the places. Mosses and Plantago major L. occurred on about 80% of the locations. Solidago canadensis L., an invasive species, was found on almost 70% of the places. Poa annua had the highest average weed cover. Mosses and Taraxacum officinale had also a high weed cover. During the time span from 2006 to 2010 a research of the efficacy of thermic weed control systems was carried out in the city of Chemnitz. The following systems were tested: 1.Hot foam system „Waipuna“ in 2006 and 2007, altogether 9 areas, 2 applications per year; 2.Hot steam system „OMK“ in 2008, 11 areas, 3 to 4 applications per year; 3.Hot water – hot steam system „Geysir“, in 2009 and 2010, altogether 10 areas, 3 to 4 applications per year. These three systems had mostly good efficacy against annual weeds and mosses. They failed to control Taraxacum officinale. None of the three systems provided a complete weed control with the above-mentioned number of applications. Weed cover was reduced by perennial application of the hot steam – hot water system „Geysir“.   &nbsp

    Species-specific paternal age effects and sperm methylation levels of developmentally important genes

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    A growing number of sperm methylome analyses have identified genomic loci that are susceptible to paternal age effects in a variety of mammalian species, including human, bovine, and mouse. However, there is little overlap between different data sets. Here, we studied whether or not paternal age effects on the sperm epigenome have been conserved in mammalian evolution and compared methylation patterns of orthologous regulatory regions (mainly gene promoters) containing both conserved and non-conserved CpG sites in 94 human, 36 bovine, and 94 mouse sperm samples, using bisulfite pyrosequencing. We discovered three (NFKB2, RASGEF1C, and RPL6) age-related differentially methylated regions (ageDMRs) in humans, four (CHD7, HDAC11, PAK1, and PTK2B) in bovines, and three (Def6, Nrxn2, and Tbx19) in mice. Remarkably, the identified sperm ageDMRs were all species-specific. Most ageDMRs were in genomic regions with medium methylation levels and large methylation variation. Orthologous regions in species not showing this age effect were either hypermethylated (>80%) or hypomethylated (<20%). In humans and mice, ageDMRs lost methylation, whereas bovine ageDMRs gained methylation with age. Our results are in line with the hypothesis that sperm ageDMRs are in regions under epigenomic evolution and may be part of an epigenetic mechanism(s) for lineage-specific environmental adaptations and provide a solid basis for studies on downstream effects in the genes analyzed here

    Transcriptomic buffering of cryptic genetic variation contributes to meningococcal virulence

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    Ampattu BJ, Hagmann L, Liang C, et al. Transcriptomic buffering of cryptic genetic variation contributes to meningococcal virulence. BMC Genomics. 2017;18(1): 282.Background: Commensal bacteria like Neisseria meningitidis sometimes cause serious disease. However, genomic comparison of hyperinvasive and apathogenic lineages did not reveal unambiguous hints towards indispensable virulence factors. Here, in a systems biological approach we compared gene expression of the invasive strain MC58 and the carriage strain alpha 522 under different ex vivo conditions mimicking commensal and virulence compartments to assess the strain-specific impact of gene regulation on meningococcal virulence. Results: Despite indistinguishable ex vivo phenotypes, both strains differed in the expression of over 500 genes under infection mimicking conditions. These differences comprised in particular metabolic and information processing genes as well as genes known to be involved in host-damage such as the nitrite reductase and numerous LOS biosynthesis genes. A model based analysis of the transcriptomic differences in human blood suggested ensuing metabolic flux differences in energy, glutamine and cysteine metabolic pathways along with differences in the activation of the stringent response in both strains. In support of the computational findings, experimental analyses revealed differences in cysteine and glutamine auxotrophy in both strains as well as a strain and condition dependent essentiality of the (p) ppGpp synthetase gene relA and of a short non-coding AT-rich repeat element in its promoter region. Conclusions: Our data suggest that meningococcal virulence is linked to transcriptional buffering of cryptic genetic variation in metabolic genes including global stress responses. They further highlight the role of regulatory elements for bacterial virulence and the limitations of model strain approaches when studying such genetically diverse species as N. meningitidis

    Knowledge transfer in pair programming: an in-depth analysis

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    Whilst knowledge transfer is one of the most widely-claimed benefits of pair programming, little is known about how knowledge transfer is achieved in this setting. This is particularly pertinent for novice-expert constellations, but knowledge transfer takes place to some degree in all constellations. We ask “what does it take to be a good “expert” and how can a “novice” best learn from a more experienced developer?”. An in-depth investigation of video and audio excerpts of professional pair programming sessions using Interaction Analysis reveals: six teaching strategies, ranging from “giving direct instructions” to “subtle hints”; and challenges and benefits for both partners. These strategies are instantiations of some but not all teaching methods promoted in cognitive apprenticeship; novice articulation, reflection and exploration are not seen in the data. The context of pair programming influences the strategies, challenges and benefits, in particular the roles of driver and navigator and agile prioritisation which considers business value rather than educational progression. Utilising these strategies more widely and recognizing the challenges and benefits for both partners will help developers to maximise the benefits from pairing sessions

    Health outcomes in offspring born to survivors of childhood cancers following assisted reproductive technologies

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    Purpose: An increasing number of childhood cancer survivors are using assisted reproductive technologies (ART) to overcome treatment-related fertility impairment. We report perinatal and health outcomes of offspring born to survivors following ART. Methods: The FeCt Multicenter Offspring Study surveyed the health of offspring of childhood cancer survivors. Health outcomes in offspring born to survivors following ART (n = 57, 4.6%) or after spontaneous conception (n = 1182) were assessed in the German cohort (n = 1239) using bivariate analysis. Findings were put into the context of the general German population by health outcome assessment in 1:1 matched-pair analysis (n = 2478). Results: Nearly twice the survivors used ART compared with numbers reported for the German general population (4.6% vs. 2.6%). Successful pregnancies were achieved after a median of two cycles, mainly using non-cryopreserved oocytes/sperm. Multiple sibling births (p < 0.001, 28.1% vs. 3.0%) and low birth weight (p = 0.008; OR = 2.659, 95% CI = 1.258-5.621) occurred significantly more often in offspring born to survivors who utilized ART than spontaneously conceived children, whereas similar percentages were born preterm or too small for their gestational age. ART did not increase the prevalence of childhood cancer or congenital malformations in offspring born to survivors. Conclusion: ART use by childhood cancer survivors was successful with both fresh and cryopreserved oocytes/sperm, and did not influence perinatal health or health outcomes when known confounders were taken into account. Implications for cancer survivors: Oncofertility is an important component of patient care. Our study implicates that the utilization of ART by adult survivors of childhood cancer does not put offspring at additional risk for adverse perinatal or health outcomes

    PERFIS HEMATOLÓGICOS, BIOQUÍMICOS E PROTEÍNA PLASMÁTICA TOTAL DE GATOS INFECTADOS COM O VÍRUS DA LEUCEMIA FELINA

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    A leucemia viral felina (FeLV) é causada por um retrovírus E pode provocar várias alterações no organismo, como distúrbios de proliferação celular (linfoma ou doenças mieloproliferativas) e de supressão celular (imunodeficiência e mielosupressão). Considerando a importância dos resultados laboratoriais no diagnóstico, avaliação clínica e determinação do prognóstico de gatos infectados, os objetivos do estudo foram descrever as alterações hematológicas, bioquímicas e de proteína plasmática total de gatos infectados com o vírus da leucemia. Foram coletadas amostras de sangue de 48 gatos infectados com FeLV e avaliados os valores de hematócrito, hemoglobina, contagem de hemácias, leucócitos, plaquetas, análise citomorfológica e contagem diferencial de leucócitos e proteína plasmática total. Os valores de alanina aminotransferase (ALT), gama-glutamiltransferase (GGT), ureia e creatinina também foram avaliados. A linfopenia foi a alteração hematológica mais comum, em 31,25% dos gatos, seguida pela presença de linfócitos reativos ou atípicos (27,1%). Houve  anemia em 16,66% dos gatos; leucocitose em 16,66%; leucopenia em 14,58%; linfocitose em 8,33%, monocitose em 14,58%, eosinofilia em 4,17%, neutrofilia em 16,66%, neutropenia em 16,66%, desvio nuclear de neutrófilos à esquerda em 14,58% e presença de neutrófilos tóxicos em 16,66%. No perfil bioquímico, em 3,16% dos animais verificou-se azotemia; no perfil hepático, as alterações foram: aumento da GGT em 18,52%, aumento da ALT em 33,33% e aumento de ambas em 7,40%. No presente estudo, constatou-se que em 78,95% dos animais houve alguma alteração no hemograma. O estudo ressalta a importância do hemograma no diagnóstico, monitoramento e determinação do prognóstico de gatos infectados com FeLV

    THz streak camera performance for single-shot characterization of XUV pulses with complex temporal structures

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    The THz-field-driven streak camera has proven to be a powerful diagnostic-technique that enables the shot-to-shot characterization of the duration and the arrival time jitter of free electron laser (FEL) pulses. Here we investigate the performance of three computational approaches capable to determine the duration of FEL pulses with complex temporal structures from single-shot measurements of up to three simultaneously recorded spectra. We use numerically simulated FEL pulses in order to validate the accuracy of the pulse length retrieval in average as well as in a single-shot mode. We discuss requirements for the THz field strength in order to achieve reliable results and compare our numerical study with the analysis of experimental data that were obtained at the FEL in Hamburg - FLASH. © 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

    Emergent dynamic chirality in a thermally driven artificial spin ratchet

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    Modern nanofabrication techniques have opened the possibility to create novel functional materials, whose properties transcend those of their constituent elements. In particular, tuning the magnetostatic interactions in geometrically frustrated arrangements of nanoelements called artificial spin ice1, 2 can lead to specific collective behaviour3, including emergent magnetic monopoles4, 5, charge screening6, 7 and transport8, 9, as well as magnonic response10, 11, 12. Here, we demonstrate a spin-ice-based active material in which energy is converted into unidirectional dynamics. Using X-ray photoemission electron microscopy we show that the collective rotation of the average magnetization proceeds in a unique sense during thermal relaxation. Our simulations demonstrate that this emergent chiral behaviour is driven by the topology of the magnetostatic field at the edges of the nanomagnet array, resulting in an asymmetric energy landscape. In addition, a bias field can be used to modify the sense of rotation of the average magnetization. This opens the possibility of implementing a magnetic Brownian ratchet13, 14, which may find applications in novel nanoscale devices, such as magnetic nanomotors, actuators, sensors or memory cells

    Biomarker, Imaging, and Clinical Factors Associated With Overt and Covert Stroke in Patients With Atrial Fibrillation.

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    BACKGROUND Atrial fibrillation is a major risk factor for stroke and silent brain infarcts. We studied whether a multimodal approach offers additional insights to the CHA2DS2-VASc score in predicting stroke or new brain infarcts on magnetic resonance imaging (MRI) over a 2-year follow-up. METHODS Swiss-AF is a prospective, multicenter cohort study of patients with known atrial fibrillation. We included patients with available brain MRI both at enrollment and 2 years later. The dates of the baseline and follow-up visits ranged from March 2014 to November 2020. The primary outcome was assessed 2 years after baseline and was defined as a composite of clinically identified stroke or any new brain infarct on the 2-year MRI. We compared a multivariable logistic regression model including prespecified clinical, biomarker, and baseline MRI variables to the CHA2DS2-VASc score. RESULTS We included 1232 patients, 89.8% of them taking oral anticoagulants. The primary outcome occurred in 78 patients (6.3%). The following baseline variables were included in the final multivariate model and were significantly associated with the primary outcome: white matter lesion volume in milliliters (adjusted odds ratio [aOR], 1.91 [95% CI, 1.45-2.56]), NT-proBNP (N-terminal pro-B-type natriuretic peptide; aOR, 1.75 [95% CI, 1.20-2.63]), GDF-15 (growth differentiation factor-15; aOR, 1.68 [95% CI, 1.11-2.53]), serum creatinine (aOR, 1.50 [95% CI, 1.02-2.22]), IL (interleukin)-6 (aOR, 1.37 [95% CI, 1.00-1.86]), and hFABP (heart-type fatty acid-binding protein; aOR, 0.48 [95% CI, 0.31-0.73]). Overall performance and discrimination of the new model was superior to that of the CHA2DS2-VASc score (C statistic, 0.82 [95% CI, 0.77-0.87] versus 0.64 [95% CI, 0.58-0.70]). CONCLUSIONS In patients with atrial fibrillation, a model incorporating white matter lesion volume on baseline MRI and selected blood markers yielded new insights on residual stroke risk despite a high proportion of patients on oral anticoagulants. This may be relevant to develop further preventive measures
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