1,845 research outputs found

    The upper-atmosphere extension of the ICON general circulation model (version: Ua-icon-1.0)

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    How the upper-atmosphere branch of the circulation contributes to and interacts with the circulation of the middle and lower atmosphere is a research area with many open questions. Inertia-gravity waves, for instance, have moved in the focus of research as they are suspected to be key features in driving and shaping the circulation. Numerical atmospheric models are an important pillar for this research. We use the ICOsahedral Non-hydrostatic (ICON) general circulation model, which is a joint development of the Max Planck Institute for Meteorology (MPI-M) and the German Weather Service (DWD), and provides, e.g., local mass conservation, a flexible grid nesting option, and a non-hydrostatic dynamical core formulated on an icosahedral-triangular grid. We extended ICON to the upper atmosphere and present here the two main components of this new configuration named UA-ICON: an extension of the dynamical core from shallow- to deep-atmosphere dynamics and the implementation of an upper-atmosphere physics package. A series of idealized test cases and climatological simulations is performed in order to evaluate the upper-atmosphere extension of ICON. © Author(s) 2019

    Understanding trade pathways to target biosecurity surveillance

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    Increasing trends in global trade make it extremely difficult to prevent the entry of all potential invasive species (IS). Establishing early detection strategies thus becomes an important part of the continuum used to reduce the introduction of invasive species. One part necessary to ensure the success of these strategies is the determination of priority survey areas based on invasion pressure. We used a pathway-centred conceptual model of pest invasion to address these questions: what role does global trade play in invasion pressure of plant ecosystems and how could an understanding of this role be used to enhance early detection strategies? We concluded that the relative level of invasion pressure for destination ecosystems can be influenced by the intensity of pathway usage (import volume and frequency), the number and type of pathways with a similar destination, and the number of different ecological regions that serve as the source for imports to the same destination. As these factors increase, pressure typically intensifies because of increasing a) propagule pressure, b) likelihood of transporting pests with higher intrinsic invasion potential, and c) likelihood of transporting pests into ecosystems with higher invasibility. We used maritime containerized imports of live plants into the contiguous U.S. as a case study to illustrate the practical implications of the model to determine hotspot areas of relative invasion pressure for agricultural and forest ecosystems (two ecosystems with high potential invasibility). Our results illustrated the importance of how a pathway-centred model could be used to highlight potential target areas for early detection strategies for IS. Many of the hotspots in agricultural and forest ecosystems were within major U.S. metropolitan areas. Invasion ecologists can utilize pathway-centred conceptual models to a) better understand the role of human-mediated pathways in pest establishment, b) enhance current methodologies for IS risk analysis, and c) develop strategies for IS early detection-rapid response programs

    Genehmigungs- und Zulassungsvoraussetzungen von Bodenmischsäulen

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    Dieser Aufsatz ist Teil des folgenden Sammelbandes: Innovationen im Spezialtiefbau : Fachseminar am 05. Dezember 2013 an der Technischen Universität Berlin. – Hrsg.: Bernd Kochendörfer. - (Bauwirtschaft und Baubetrieb : Berichte ; 2). – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2663-7 (print) ISBN 978-3-7983-2664-4 (online) URN urn:nbn:de:kobv:83-opus4-44427 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-44427]Vorliegender Beitrag behandelt die technischen und genehmigungsrechtlichen Belange beim Einsatz von sogenannten Bodenmischsäulen zur Verbesserung der Baugrundeigenschaften bzw. zur Herstellung eines lastab-tragenden Elementes im Untergrund

    Viewpoint: filovirus haemorrhagic fever outbreaks: much ado about nothing?

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    The recent outbreak of Marburg haemorrhagic fever in the Democratic Republic of Congo has put the filovirus threat back on the international health agenda. This paper gives an overview of Marburg and Ebola outbreaks so far observed and puts them in a public health perspective. Damage on the local level has been devastating at times, but was marginal on the international level despite the considerable media attention these outbreaks received. The potential hazard of outbreaks, however, after export of filovirus from its natural environment into metropolitan areas, is argued to be considerable. Some avenues for future research and intervention are explored. Beyond the obvious need to find the reservoir and study the natural history, public health strategies for a more timely and efficient response are urgently needed

    Repression of human activation induced cytidine deaminase by miR-93 and miR-155

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    BACKGROUND: Activation Induced cytidine Deaminase (AID) targets the immunoglobulin genes of activated B cells, where it converts cytidine to uracil to induce mutagenesis and recombination. While essential for immunoglobulin gene diversification, AID misregulation can result in genomic instability and oncogenic transformation. This is classically illustrated in Burkitt's lymphoma, which is characterized by AID-induced mutation and reciprocal translocation of the c-MYC oncogene with the IgH loci. Originally thought to be B cell-specific, AID now appears to be misexpressed in several epithelial cancers, raising the specter that AID may also participate in non-B cell carcinogenesis. METHODS: The mutagenic potential of AID argues for the existence of cellular regulators capable of repressing inappropriate AID expression. MicroRNAs (miRs) have this capacity, and we have examined the publically available human AID EST dataset for miR complementarities to the human AID 3'UTR. In this work, we have evaluated the capacity of two candidate miRs to repress human AID expression in MCF-7 breast carcinoma cells. RESULTS: We have discovered moderate miR-155 and pronounced miR-93 complementary target sites encoded within the human AID mRNA. Luciferase reporter assays indicate that both miR-93 and miR-155 can interact with the 3'UTR of AID to block expression. In addition, over-expression of either miR in MCF-7 cells reduces endogenous AID protein, but not mRNA, levels. Similarly indicative of AID translational regulation, depletion of either miR in MCF-7 cells increases AID protein levels without concurrent increases in AID mRNA. CONCLUSIONS: Together, our findings demonstrate that miR-93 and miR-155 constitutively suppress AID translation in MCF-7 cells, suggesting widespread roles for these miRs in preventing genome cytidine deaminations, mutagenesis, and oncogenic transformation. In addition, our characterization of an obscured miR-93 target site located within the AID 3'UTR supports the recent suggestion that many miR regulations have been overlooked due to the prevalence of truncated 3'UTR annotations

    Zonas globais de resistência às plantas para análise de risco fitossanitário

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    Plant hardiness zones are widely used for selection of perennial plants and for phytosanitary risk analysis. The most widely used definition of plant hardiness zones (United States Department of Agriculture National Arboretum) is based on average annual extreme minimum temperature. There is a need for a global plant hardiness map to standardize the comparison of zones for phytosanitary risk analysis. Two data sets were used to create global hardiness zones: i) Climate Research Unit (CRU) 1973-2002 monthly data set; and ii) the Daily Global Historical Climatology Network (GHCN). The CRU monthly data set was downscaled to five-minute resolution and a cubic spline was used to convert the monthly values into daily values. The GHCN data were subjected to a number of quality control measures prior to analysis. Least squares regression relationships were developed using GHCN and derived lowest average daily minimum temperature data and average annual extreme minimum temperatures. Error estimate statistics were calculated from the numerical difference between the estimated value for the grid and the station. The mean absolute error for annual extreme minimum temperature was 1.9ºC (3.5ºF) and 2/3 of the stations were classified into the correct zone.Zonas de resistência às plantas, definidas pelo " United States Department of Agriculture National Arboretum" com base na média anual das temperaturas mínimas extremas, são amplamente utilizadas para a seleção de plantas perenes e para a análise de risco fitossanitário. Há necessidade de um mapa global para padronizar a comparação de zonas nas análises de risco fitossanitário. Dois bancos de dados climatológicos foram utilizados para criar tais zonas globais de resistência às plantas: i) conjunto de dados mensais de 1973-2002 da " Climate Research Unit (CRU)" ; e ii) dados climatológicos diários da " Daily Global Historical Climatology Network (GHCN)" . Os dados mensais da CRU foram ajustados a uma escala reduzida de resolução de cinco minutos, e um ajuste cúbico foi empregado para converter os dados mensais para diários. Os dados da RDGH foram submetidos a várias medidas de controle de qualidade antes de serem empregados nas análises. Relações de regressão pelo método dos mínimos quadrados foram desenvolvidas usando dados da RDGH, resultando nos mais baixos valores médios diários de temperatura mínima e média anual das temperaturas mínimas extremas. Os erros estatísticos estimados foram calculados a partir da diferença numérica entre os valores estimados para a malha e os observados nas estações climatológicas. O erro médio absoluto para a temperatura mínima extrema anual foi 1,9ºC (3,5ºF), o que possibilitou a classificação de 2/3 das estações dentro das zonas corretas

    Organisation of Health Care During an Outbreak of Marburg Haemorrhagic Fever in the Democratic Republic of Congo, 1999.

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    Organising health care was one of the tasks of the International Scientific and Technical Committee during the 1998-1999 outbreak in Durba/Watsa, in the north-eastern province (Province Orientale), Democratic Republic of Congo. With the logistical support of Médecins sans Frontières (MSF), two isolation units were created: one at the Durba Reference Health Centre and the other at the Okimo Hospital in Watsa. Between May 6th, the day the isolation unit was installed and May 19th, 15 patients were admitted to the Durba Health Centre. In only four of them were the diagnosis of Marburg haemorrhagic fever (MHF) confirmed by laboratory examination. Protective equipment was distributed to health care workers and family members caring for patients. Information about MHF, modes of transmission and the use of barrier nursing techniques was provided to health care workers and sterilisation procedures were reviewed. In contrast to Ebola outbreaks, there was little panic among health care workers and the general public in Durba and all health services remained operational

    Measurement of the charged pion mass using X-ray spectroscopy of exotic atoms

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    The 5g−4f5g-4f transitions in pionic nitrogen and muonic oxygen were measured simultaneously by using a gaseous nitrogen-oxygen mixture at 1.4\,bar. Due to the precise knowledge of the muon mass the muonic line provides the energy calibration for the pionic transition. A value of (139.57077\,±\pm\,0.00018)\,MeV/c2^{2} (±\pm\,1.3ppm) is derived for the mass of the negatively charged pion, which is 4.2ppm larger than the present world average

    Nuclear effects in atomic transitions

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    Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects that can be identified in atomic structure data. An introduction to the theory of isotope shifts and hyperfine splitting of atomic spectra is given, together with an overview of the typical experimental techniques used in high-precision atomic spectroscopy. More exotic effects at the borderline between atomic and nuclear physics, such as parity violation in atomic transitions due to the weak interaction, or nuclear polarization and nuclear excitation by electron capture, are also addressed.Comment: review article, 53 pages, 14 figure
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