293 research outputs found

    Fertigung laminarer optischer Gitter am HZB

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    Laminare optische Gitter stellen höchste Anforderungen an die mikrosystemtechnische Fertigung der Mikro und Nano strukturen in Hinsicht auf PrĂ€zision und HomogenitĂ€t. Im Rahmen des EU Projektes Aufbau eines Technologiezent rums fĂŒr hocheffiziente optische PrĂ€zisionsgitter am Helmholtz Zentrum Berlin HZB EFRE Vertrag Nr. 20072013 2 43 [1,2] wurden die fĂŒr die Herstellung von laminaren und geblazten Gittern notwendigen Anlagen in Betrieb ge nommen. Gleichzeitig wurde mit der Prozessentwicklung begonnen. In diesem Artikel werden die neuesten Prozessergebnisse von durch Laserinterferenzlithographie LIL in Photoresist erzeugter Gitterstrukturen und deren nur wenige Nanometer tiefe Übertragung in Siliziumsubstrate mittels Ionenstrahl Ă€tzen vorgestellt. english version Laminar optical gratings impose highest demands on microsystem technological manufacturing with regard to precision and uniformity. Within the project Installation of a technology centre for highly efficient precision gratings at Helm holtz Zentrum Berlin HZB EFRE Vertrag Nr. 20072013 2 43 [1,2] the necessary systems for the manufacturing of laminar and blazed gratings were taken into operation and process development has started. In this article we present the results of grating structures manufactured with laser interference lithography and subse quent ion beam etchin

    INTRASEASONAL VARIABILITY OF GUANO STAINS IN A REMOTELY SENSED PENGUIN COLONY USING UAV AND SATELLITE

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    Remote sensing of penguins gives a unique opportunity to observe ecosystem changes in the Antarctic and the Southern Ocean at a continent-wide scale. The extent of guano is the best proxy to the size of penguin populations but frequent cloud cover limits the number of available images. This study focuses on the correlation between guano coverage visible in aerial and satellite images and breeding pair numbers in the course of the breeding seasons 2016/17 and 2017/18 in a colony of Pygocelid penguins on Ardley Island (South Shetland Islands, Antarctica). Multitemporal UAV (Unmanned Aerial Vehicle) orthomosaics and high-resolution satellite images were collected of Ardley Island as well as data on breeding phenology, weather conditions and snow coverage. “Fresh” guano stains were classified using different methods of Geographical Object-based Image Analysis (GEOBIA) and differentiated from weathered guano stains. Analysis of this data shows that guano stains in an Antarctic Pygoscelid penguin colony undergo significant intraseasonal changes in extent, texture and spectral signature. Hence, the timing of image acquisition and the advance of snow melt during Antarctic spring matter when determining penguin populations and should be considered during the analysis. Our results show changes of up to 25 % of the total guano covered surface due to individual weather events and changes up to 80 % in the time between the peak of egg laying and the occurrence of the first crĂšche

    The at wavelength metrology facility for UV and XUV reflection and diffraction optics at BESSY II

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    A technology center for the production of high precision reflection gratings has been established. Within this project a new optics beamline and a versatile reflectometer for at wavelength characterization of UV and XUV reflection gratings and other nano optical elements has been set up at BESSY II. The Plane Grating Monochromator beamline operated in collimated light c PGM is equipped with an SX700 monochromator, of which the blazed gratings 600 and 1200 lines mm 1 have been recently exchanged for new ones of improved performance produced in house. Over the operating range from 10 to 2000 eV this beamline has very high spectral purity achieved by i a four mirror arrangement of different coatings which can be inserted into the beam at different angles and ii by absorber filters for high order suppression. Stray light and scattered radiation is removed efficiently by double sets of in situ exchangeable apertures and slits. By use of in and off plane bending magnet radiation the beamline can be adjusted to either linear or elliptical polarization. One of the main features of a novel 11 axes reflectometer is the possibility to incorporate real life sized gratings. The samples are adjustable within six degrees of freedom by a newly developed UHV tripod system carrying a load up to 4 kg, and the reflectivity can be measured between 0 and 90 deg incidence angle for both s and p polarization geometry. This novel powerful metrology facility has gone into operation recently and is now open for external users. First results on optical performance and measurements on multilayer gratings will be presented her

    Globally consistent climate sensitivity of natural disturbances across boreal and temperate forest ecosystems

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    Disturbance regimes are changing in forests across the world in response to global climate change. Despite the profound impacts of disturbances on ecosystem services and biodiversity, assessments of disturbances at the global scale remain scarce. Here, we analyzed natural disturbances in boreal and temperate forest ecosystems for the period 2001-2014, aiming to 1) quantify their within- and between-biome variation and 2) compare the climate sensitivity of disturbances across biomes. We studied 103 unmanaged forest landscapes with a total land area of 28.2 x 10(6) ha, distributed across five continents. A consistent and comprehensive quantification of disturbances was derived by combining satellite-based disturbance maps with local expert knowledge of disturbance agents. We used Gaussian finite mixture models to identify clusters of landscapes with similar disturbance activity as indicated by the percent forest area disturbed as well as the size, edge density and perimeter-area-ratio of disturbed patches. The climate sensitivity of disturbances was analyzed using Bayesian generalized linear mixed effect models and a globally consistent climate dataset. Within-biome variation in natural disturbances was high in both boreal and temperate biomes, and disturbance patterns did not vary systematically with latitude or biome. The emergent clusters of disturbance activity in the boreal zone were similar to those in the temperate zone, but boreal landscapes were more likely to experience high disturbance activity than their temperate counterparts. Across both biomes high disturbance activity was particularly associated with wildfire, and was consistently linked to years with warmer and drier than average conditions. Natural disturbances are a key driver of variability in boreal and temperate forest ecosystems, with high similarity in the disturbance patterns between both biomes. The universally high climate sensitivity of disturbances across boreal and temperate ecosystems indicates that future climate change could substantially increase disturbance activity.Peer reviewe

    Ecosystem Resilience Monitoring and Early Warning Using Earth Observation Data: Challenges and Outlook

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    As the Earth system is exposed to large anthropogenic interferences, it becomes ever more important to assess the resilience of natural systems, i.e., their ability to recover from natural and human-induced perturbations. Several, often related, measures of resilience have been proposed and applied to modeled and observed data, often by different scientific communities. Focusing on terrestrial ecosystems as a key component of the Earth system, we review methods that can detect large perturbations (temporary excursions from a reference state as well as abrupt shifts to a new reference state) in spatio-temporal datasets, estimate the recovery rate after such perturbations, or assess resilience changes indirectly from stationary time series via indicators of critical slowing down. We present here a sequence of ideal methodological steps in the field of resilience science, and argue how to obtain a consistent and multi-faceted view on ecosystem or climate resilience from Earth observation (EO) data. While EO data offers unique potential to study ecosystem resilience globally at high spatial and temporal scale, we emphasize some important limitations, which are associated with the theoretical assumptions behind diagnostic methods and with the measurement process and pre-processing steps of EO data. The latter class of limitations include gaps in time series, the disparity of scales, and issues arising from aggregating time series from multiple sensors. Based on this assessment, we formulate specific recommendations to the EO community in order to improve the observational basis for ecosystem resilience research

    Genome-wide identification of FoxO-dependent gene networks in skeletal muscle during C26 cancer cachexia

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    BACKGROUND: Evidence from cachectic cancer patients and animal models of cancer cachexia supports the involvement of Forkhead box O (FoxO) transcription factors in driving cancer-induced skeletal muscle wasting. However, the genome-wide gene networks and associated biological processes regulated by FoxO during cancer cachexia are unknown. We hypothesize that FoxO is a central upstream regulator of diverse gene networks in skeletal muscle during cancer that may act coordinately to promote the wasting phenotype. METHODS: To inhibit endogenous FoxO DNA-binding, we transduced limb and diaphragm muscles of mice with AAV9 containing the cDNA for a dominant negative (d.n.) FoxO protein (or GFP control). The d.n.FoxO construct consists of only the FoxO3a DNA-binding domain that is highly homologous to that of FoxO1 and FoxO4, and which outcompetes and blocks endogenous FoxO DNA binding. Mice were subsequently inoculated with Colon-26 (C26) cells and muscles harvested 26 days later. RESULTS: Blocking FoxO prevented C26-induced muscle fiber atrophy of both locomotor muscles and the diaphragm and significantly spared force deficits. This sparing of muscle size and function was associated with the differential regulation of 543 transcripts (out of 2,093) which changed in response to C26. Bioinformatics analysis of upregulated gene transcripts that required FoxO revealed enrichment of the proteasome, AP-1 and IL-6 pathways, and included several atrophy-related transcription factors, including Stat3, Fos, and Cebpb. FoxO was also necessary for the cancer-induced downregulation of several gene transcripts that were enriched for extracellular matrix and sarcomere protein-encoding genes. We validated these findings in limb muscles and the diaphragm through qRT-PCR, and further demonstrate that FoxO1 and/or FoxO3a are sufficient to increase Stat3, Fos, Cebpb, and the C/EBPÎČ target gene, Ubr2. Analysis of the Cebpb proximal promoter revealed two bona fide FoxO binding elements, which we further establish are necessary for Cebpb promoter activation in response to IL-6, a predominant cytokine in the C26 cancer model. CONCLUSIONS: These findings provide new evidence that FoxO-dependent transcription is a central node controlling diverse gene networks in skeletal muscle during cancer cachexia, and identifies novel candidate genes and networks for further investigation as causative factors in cancer-induced wasting.R01 AR060217 - NIAMS NIH HHS; R01 AR060209 - NIAMS NIH HHS; T32 HD043730 - NICHD NIH HHS; R00 HL098453 - NHLBI NIH HHS; R00HL098453 - NHLBI NIH HHS; R01AR060209 - NIAMS NIH HHS; R01AR060217 - NIAMS NIH HH

    Major submissions tool developments at the European nucleotide archive

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    The European Nucleotide Archive (ENA; http://www.ebi.ac.uk/ena), Europe's primary nucleotide sequence resource, captures and presents globally comprehensive nucleic acid sequence and associated information. Covering the spectrum from raw data to assembled and functionally annotated genomes, the ENA has witnessed a dramatic growth resulting from advances in sequencing technology and ever broadening application of the methodology. During 2011, we have continued to operate and extend the broad range of ENA services. In particular, we have released major new functionality in our interactive web submission system, Webin, through developments in template-based submissions for annotated sequences and support for raw next-generation sequence read submissions

    The impact of mineral dust on cloud formation during the Saharan dust event in April 2014 over Europe

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    A regional modeling study on the impact of desert dust on cloud formation is presented for a major Saharan dust outbreak over Europe from 2 to 5 April 2014. The dust event coincided with an extensive and dense cirrus cloud layer, suggesting an influence of dust on atmospheric ice nucleation. Using interactive simulation with the regional dust model COSMO-MUSCAT, we investigate cloud and precipitation representation in the model and test the sensitivity of cloud parameters to dust–cloud and dust–radiation interactions of the simulated dust plume. We evaluate model results with ground-based and spaceborne remote sensing measurements of aerosol and cloud properties, as well as the in situ measurements obtained during the ML-CIRRUS aircraft campaign. A run of the model with single-moment bulk microphysics without online dust feedback considerably underestimated cirrus cloud cover over Germany in the comparison with infrared satellite imagery. This was also reflected in simulated upper-tropospheric ice water content (IWC), which accounted for only 20&thinsp;% of the observed values. The interactive dust simulation with COSMO-MUSCAT, including a two-moment bulk microphysics scheme and dust–cloud as well as dust–radiation feedback, in contrast, led to significant improvements. The modeled cirrus cloud cover and IWC were by at least a factor of 2 higher in the relevant altitudes compared to the noninteractive model run. We attributed these improvements mainly to enhanced deposition freezing in response to the high mineral dust concentrations. This was corroborated further in a significant decrease in ice particle radii towards more realistic values, compared to in situ measurements from the ML-CIRRUS aircraft campaign. By testing different empirical ice nucleation parameterizations, we further demonstrate that remaining uncertainties in the ice-nucleating properties of mineral dust affect the model performance at least as significantly as including the online representation of the mineral dust distribution. Dust–radiation interactions played a secondary role for cirrus cloud formation, but contributed to a more realistic representation of precipitation by suppressing moist convection in southern Germany. In addition, a too-low specific humidity in the 7 to 10&thinsp;km altitude range in the boundary conditions was identified as one of the main reasons for misrepresentation of cirrus clouds in this model study.</p
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