185 research outputs found

    Design of an imaging spectrometer for Earth observation using freeform mirrors

    Get PDF
    Design of an imaging spectrometer for earth observation using freeform mirrors Thomas Peschel1, Christoph Damm1, Matthias Beier1, Andreas Gebhard1, Stefan Risse1, Ingo Walter2, Ilse Sebastian2, David Krutz2 1 Fraunhofer Institut für Angewandte Optik und Feinwerktechnik, Jena 2 DLR, Institut für Optische Sensorsysteme, Berlin In 2017 the new hyperspectral DLR Earth Sensing Imaging Spectrometer (DESIS) will be integrated in the Multi-User-System for Earth Sensing (MUSES) platform /1/ installed on the International Space Station (ISS). The DESIS instrument is developed under the responsibility of the DLR. It will deliver images of the earth with a spatial resolution of 30 m on ground in 235 spectral channels in the wavelength range from 400 nm to 1 µm. As partner of the development team Fraunhofer IOF is responsible for the optical system of the imaging spectrometer.The optical system is made of two primary components: A compact Three-Mirror-Anastigmat (TMA) telescope images the ground strip under observation onto a slit. The following spectrometer reimages the slit onto the detector and performs the spectral separation using a reflective grating. The whole optical system is realized using metal-based mirrors the surfaces of which are made by Single-Point-Diamond Turning (SPDT). Since the spectral range is in the visible, a post-processing of the surfaces by Nickel plating is necessary. The final surface shape and roughness are realized by a second SPDT step and subsequent Magneto-Rheological Finishing. The TMA provides a focal length of 320 mm and an aperture of F/2.8. Its mechanical design relies on the Duolith-technology of IOF as well as optical and mechanical reference structures on the mirrors /2/ manufactured in the same SPDT run. This strategy allows for a significantly simplified adjustment of the optical system /3/. The spectrometer was designed on the basis of the so-called Offner scheme. Because of the high aperture of the system a freeform mirror had to be introduced in order to provide a good imaging quality over the whole spectral range. The above optical design requires a grating on a curved surface. Technologies are developed in order to fabricate the grating either by SPDT or, alternatively, by laser lithography. The mechanical design uses light-weight housing elements which wrap the optical path to suppress stray light. An athermal design is provided by using the same metal for mirrors and housing. To provide high adjustment precision, the housing elements carry reference and mounting features made by SPDT as well. This approach allows for a stiff mechanical set-up of the system, which is compatible with the harsh requirements of a space flight. References: 1 N. Humphrey, “A View From Above: Imaging from the ISS”, Teledyne DALSA 2014, http://possibility.teledynedalsa.com/a-view-from-above/ 2 S. Scheiding, e.a., “Ultra-precisely manufactured mirror assemblies with well-defined reference structures“, Proc. SPIE 7739, 2010. 3 T. Peschel, e.a., “Anamorphotic telescope for earth observation in the mid-infrared range”, ICSO 201

    Poseidon Berichte - Paphsanias Volcano Cruise POS512, 25.04.2017 – 06.05.2017, Heraklion (Griechenland) – Heraklion (Griechenland)

    Get PDF
    Summary Cruise POS512 was scheduled for ten working days from 25.4. to 6.5.2017 in order to (1) produce a bathymetric map of the Epidavros Basin near the peninsula of Methana, (2) survey the volcanic structures of the Paphsanias Volcanic Field with the ROV PHOCA, and (3) sample the volcanic rocks. The Paphsanias Volcanic Field was found in 1987 but only one rock sample had been recovered and the size, age and composition of the lavas were unknown. Historic reports suggested an eruption on Methana and potentially off the coast some 2000 years ago. The bathymetric survey showed that six volcanic structures form the volcanic field ranging from simple lava flows on the seafloor, small cone-like structures to relatively complex crater-like structures with small volcanic domes. The largest volcanoes are about 200 m high and have diameters of about 2 km. The northern two complex Volcanoes 1 and 2 are relatively young and consist of steep lava flows and dome-like structures with little sediment. No indication of very young volcanism and hydrothermal activity was found. In contrast, the four southern structures are mostly sediment-covered and outcrops of volcanic rocks are rare and often covered by thick carbonate and MnOOH crusts. These four edifices are older than the northern two. Lava samples range from olivine-bearing basalts to plagioclase-amphibole-biotite-phyric andesites and dacites. All lavas appear to be fresh but few show signs of submarine extrusion and quenching. Volcaniclastic material was rarely observed and sampled indicating that explosive volcanic activity did not occur. During cruise POS512 13 ROV dives recovered 163 samples including 131 fresh lavas from four different volcanoes of the Paphsanias Volcanic Field and 427 nm of bathymetric survey was carried out

    Wellbeing of Families in Future Europe

    Get PDF
    FAMILYPLATFORM’s aim was to develop and publish a European Research Agenda for Research on Families and Family Policy, in order to enable policy makers and others to respond to current and future challenges facing families. Four concrete steps were taken towards elaborating the Research Agenda: 1. Charting the contemporary field of research on families and family policy in the EU. 2. Critically reviewing existing research involving a wide range of stakeholders. 3. An innovative exercise to identify future challenges facing families, so as to highlight future policy issues and develop questions for future research. 4. Bringing together all of the work into a Research Agenda on Families and Family Wellbeing for Europe. Each of these areas has a dedicated chapter in this book, presenting the main results and findings of this work. More than 120 civil society representatives, policy makers, and scientific experts were involved in the work of FAMILYPLATFORM. The sharing and negotiating of sometimes contradictory perspectives and thoughts was an exciting challenge for everyone involved, resulting in a great deal of shared learning. We hope that this book passes on some of these rich experiences, thereby improving the wellbeing of families in Europe through research and policy.Wellbeing of Families in Future Europe – Challenges for Research and Policy presents the results of the FAMILYPLATFORM project, a social platform on research for families and family policy

    A homolog of <i>blade-on-petiole</i> <i>1</i> and <i>2</i> (<i>BOP1/2</i>) controls internode length and homeotic changes of the barley inflorescence

    Get PDF
    Inflorescence architecture in small-grain cereals has a direct effect on yield and is an important selection target in breeding for yield improvement. We analyzed the recessive mutation laxatum-a (lax-a) in barley (Hordeum vulgare), which causes pleiotropic changes in spike development, resulting in (1) extended rachis internodes conferring a more relaxed inflorescence, (2) broadened base of the lemma awns, (3) thinner grains that are largely exposed due to reduced marginal growth of the palea and lemma, and (4) and homeotic conversion of lodicules into two stamenoid structures. Map-based cloning enforced by mapping-by-sequencing of the mutant lax-a locus enabled the identification of a homolog of BLADE-ON-PETIOLE1 (BOP1) and BOP2 as the causal gene. Interestingly, the recently identified barley uniculme4 gene also is a BOP1/2 homolog and has been shown to regulate tillering and leaf sheath development. While the Arabidopsis (Arabidopsis thaliana) BOP1 and BOP2 genes act redundantly, the barley genes contribute independent effects in specifying the developmental growth of vegetative and reproductive organs, respectively. Analysis of natural genetic diversity revealed strikingly different haplotype diversity for the two paralogous barley genes, likely affected by the respective genomic environments, since no indication for an active selection process was detected

    Wellbeing of Families in Future Europe

    Get PDF
    FAMILYPLATFORM’s aim was to develop and publish a European Research Agenda for Research on Families and Family Policy, in order to enable policy makers and others to respond to current and future challenges facing families. Four concrete steps were taken towards elaborating the Research Agenda: 1. Charting the contemporary field of research on families and family policy in the EU. 2. Critically reviewing existing research involving a wide range of stakeholders. 3. An innovative exercise to identify future challenges facing families, so as to highlight future policy issues and develop questions for future research. 4. Bringing together all of the work into a Research Agenda on Families and Family Wellbeing for Europe. Each of these areas has a dedicated chapter in this book, presenting the main results and findings of this work. More than 120 civil society representatives, policy makers, and scientific experts were involved in the work of FAMILYPLATFORM. The sharing and negotiating of sometimes contradictory perspectives and thoughts was an exciting challenge for everyone involved, resulting in a great deal of shared learning. We hope that this book passes on some of these rich experiences, thereby improving the wellbeing of families in Europe through research and policy.Wellbeing of Families in Future Europe – Challenges for Research and Policy presents the results of the FAMILYPLATFORM project, a social platform on research for families and family policy

    BARM and BalticMicrobeDB, a reference metagenome and interface to meta-omic data for the Baltic Sea

    Get PDF
    The Baltic Sea is one of the world’s largest brackish water bodies and is characterised by pronounced physicochemical gradients where microbes are the main biogeochemical catalysts. Meta-omic methods provide rich information on the composition of, and activities within, microbial ecosystems, but are computationally heavy to perform. We here present the Baltic Sea Reference Metagenome (BARM), complete with annotated genes to facilitate further studies with much less computational effort. The assembly is constructed using 2.6 billion metagenomic reads from 81 water samples, spanning both spatial and temporal dimensions, and contains 6.8 million genes that have been annotated for function and taxonomy. The assembly is useful as a reference, facilitating taxonomic and functional annotation of additional samples by simply mapping their reads against the assembly. This capability is demonstrated by the successful mapping and annotation of 24 external samples. In addition, we present a public web interface, BalticMicrobeDB, for interactive exploratory analysis of the dataset

    Effectiveness of the AS03-Adjuvanted Vaccine against Pandemic Influenza Virus A/(H1N1) 2009 – A Comparison of Two Methods; Germany, 2009/10

    Get PDF
    During the autumn wave of the pandemic influenza virus A/(H1N1) 2009 (pIV) the German population was offered an AS03-adjuvanted vaccine. The authors compared results of two methods calculating the effectiveness of the vaccine (VE). The test-negative case-control method used data from virologic surveillance including influenza-positive and negative patients. An innovative case-series methodology explored data from all nationally reported laboratory-confirmed influenza cases. The proportion of reported cases occurring in vaccinees during an assumed unprotected phase after vaccination was compared with that occurring in vaccinees during their assumed protected phase. The test-negative case-control method included 1,749 pIV cases and 2,087 influenza test-negative individuals of whom 6 (0.3%) and 36 (1.7%), respectively, were vaccinated. The case series method included data from 73,280 cases. VE in the two methods was 79% (95% confidence interval (CI) = 35–93%; P = 0.007) and 87% (95% CI = 78–92%; P<0.001) for individuals less than 14 years of age and 70% (95% CI = −45%–94%, P = 0.13) and 74% (95% CI = 64–82%; P<0.001) for individuals above the age of 14. Both methods yielded similar VE in both age groups; and VE for the younger age group seemed to be higher
    • …
    corecore