104 research outputs found
Succession rules and leadership rents
No full textLeaders compensate supporters not just for performing their duties but also in order to preempt an overthrow by the same supporters. We show how succession rules affect the power of leaders relative to supporters as well as the resources expended on possible succession struggles. We compare two regimes of leadership succession: the conclave regime and the divide-et-impera regime which differ with respect to the role of supporters of the previous leader once the new leader takes power. The leadership rent is higher and supporters receive a lower compensation in the divide-et-impera regime, as supporters have to fight harder for succession to avoid the grim outcome of loss. Leaders, then, would like to induce the divide-et-impera regime even when every supporter has veto power over his leadership. -- Könige und Diktatoren, aber auch die Vorstände von Unternehmen und Parteivorsitzende verdanken den Fortbestand ihrer Herrschaft der Unterstützung einer Gruppe von einflussreichen Helfern in Schlüsselpositionen. Diese können ihren Einfluss für, aber auch gegen den Fortbestand der bestehenden Herrschaft einsetzen und werden von den Herrschenden in der Regel für ihre Loyalität bezahlt. Wir untersuchen, welchen Einfluss bestimmte, in der Realität praktizierte Nachfolgeregelungen auf die Machtverteilung zwischen Herrschern und ihren Gefolgsleuten haben und wie diese Nachfolgeregeln die Verteilung der Vorteile und Renten aus Herrschaft beeinflussen. Wir vergleichen zwei unterschiedliche Regime der Nachfolgeregelungen: Das so genannte Konklave- Regime und das divide-et-impera-Regime. Die beiden unterscheiden sich darin, welche Rolle den Gefolgsleute des alten Herrschers im Zusammenhang mit der Neubesetzung des Amts des Herrschers und der Schlüsselpositionen der Unterstützer unter dem neuen Herrscher zukommt. Der Nutzen des Herrschers ist höher und Gefolgsleute erhalten im divide-et-impera-Regime einen geringeren Anteil an den Renten, die mit der Herrschaft einher gehen, da sie um die Nachfolge härter kämpfen, weil sie im Zuge des Herrschaftswechsels mehr zu verlieren haben. Daher sind Herrscher bestrebt, das divide-et- impera- Regime einzuführen.Political leadership,political support,political survival,successorship
in the ventral midline of the CNS
No full textInternational audienceABSTRACT The secreted molecule Sonic hedgehog (Shh) is crucial for floor plate and ventral brain development in amniote embryos. In zebrafish, mutations in cyclops (cyc), a gene that encodes a distinct signal related to the TGFβ family member Nodal, result in neural tube defects similar to those of shh null mice. cyc mutant embryos display cyclopia and lack floor plate and ventral brain regions, suggesting a role for Cyc in specification of these structures. cyc mutants express shh in the notochord but lack expression of shh in the ventral brain. Here we show that Cyc signalling can act directly on shh expression in neural tissue. Modulation of the Cyc signalling pathway by constitutive activation or inhibition of Smad2 leads to altered shh expression in zebrafish embryos. Ectopic activation of the shh promoter occurs in response to expression of Cyc signal transducers in the chick neural tube. Furthermore an enhancer of the shh gene, which controls ventral neural tube expression, is responsive to Cyc signal transducers. Our data imply that the Nodal related signal Cyc induces shh expression in the ventral neural tube. Based on the differential responsiveness of shh and other neural tube specific genes to Hedgehog and Cyc signalling, a two-step model for the establishment of the ventral midline of the CNS is proposed
The Sunrise Ultraviolet Spectropolarimeter and Imager: Instrument Description
No full textFeller, A. et al.-- Full list of authors: Feller, Alex; Gandorfer, Achim; Grauf, Bianca; Hölken, Johannes; Iglesias, Francisco A.; Korpi-Lagg, Andreas; Riethmüller, Tino L.; Staub, Jan; Fernandez-Rico, German; Castellanos Durán, Juan Sebastián; Solanki, Sami K.; Smitha, H. N.; Sant, Kamal; Barthol, Peter; Bayon Laguna, Montserrat; Bergmann, Melani; Bischoff, Jörg; Bochmann, Jan; Bruns, Stefan; Deutsch, Werner; Eberhardt, Michel; Enge, Rainer; Goodyear, Sam; Heerlein, Klaus; Heinrichs, Jan; Hirche, Dennis; Meining, Stefan; Mende, Roland; Meyer, Sabrina; Mühlhaus, Maria; Müller, Marc Ferenc; Monecke, Markus; Oberdorfer, Dietmar; Papagiannaki, Ioanna; Ramanath, Sandeep; Vergöhl, Michael; Vukadinović, Dušan; Werner, Stephan; Zerr, Andreas; Berkefeld, Thomas; Bernasconi, Pietro; Katsukawa, Yukio; del Toro Iniesta, Jose Carlos; Bell, Alexander; Carpenter, Michael; Álvarez Herrero, Alberto; Kubo, Masahito; Martínez Pillet, Valentín; Orozco Suárez, DavidThe third science flight of the balloon-borne solar observatory Sunrise carries three entirely new post-focus science instruments with spectropolarimetric capabilities, concurrently covering an extended spectral range from the near ultraviolet to the near infrared. Sampling a larger height range, from the low photosphere to the chromosphere, with the sub-arcsecond resolution provided by the 1-m Sunrise telescope, is key in understanding critical small-scale phenomena which energetically couple different layers of the solar atmosphere. The Sunrise UV Spectropolarimeter and Imager (SUSI) operates between 309 nm and 417 nm. A key feature of SUSI is its capability to record up to several hundred spectral lines simultaneously without the harmful effects of the Earth’s atmosphere. The rich SUSI spectra can be exploited in terms of many-line inversions. Another important innovation of the instrument is the synchronized 2D context imaging which allows to numerically correct the spectrograph scans for residual optical aberrations. In this work we describe the main design aspects of SUSI, the instrument characterization and testing, and finally its operation, expected performance and data products. © The Author(s) 2025Open Access funding enabled and organized by Projekt DEAL. The German contribution to Sunrise iii and SUSI is funded by the Strategic Innovations Fund of the President of the Max Planck Society (MPG), and by the Max-Planck-Förderstiftung with private donations by supporting members of the MPG. SUSI has also received funding from the Bundesministerium für Wirtschaft und Klimaschutz through Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), grant. no. 50 OO 1608, and from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 101097844, project WINSUN). The contributions of J. Hölken, D. Vukadinović and K. Sant are supported by the International Max Planck Research School (IMPRS) for solar system science. F. Iglesias is a member of the “Carrera del Investigador Científico” of CONICET and supported by the MPG through the Max Planck Partner Group between MPS and the University of Mendoza, Argentina. The Japanese contribution has been funded by the ISAS/JAXA Small Mission-of-Opportunity program and JSPS KAKENHI JP18H05234/JP23H01220. The Spanish contribution has been funded by the Spanish MCIN/AEI under projects RTI2018-096886-B-C5, and PID2021-125325OB-C5; and from the “Center of Excellence Severo Ochoa” awards to IAA-CSIC (SEV-2017-0709, CEX2021-001131-S), all co-funded by European ERDF funds, “A way of making Europe”.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (SEV-2017-0709).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).Peer reviewe
SUNRISE III: Overview of Observatory and Instruments
No full textKorpi-Lagg, A. et al.-- Full litst of authors: Korpi-Lagg, Andreas; Gandorfer, Achim; Solanki, Sami K.; del Toro Iniesta, Jose Carlos; Katsukawa, Yukio; Bernasconi, Pietro; Berkefeld, Thomas; Feller, Alex; Riethmüller, Tino L.; Álvarez-Herrero, Alberto; Kubo, Masahito; Martínez Pillet, Valentín; Smitha, H. N.; Orozco Suárez, David; Grauf, Bianca; Carpenter, Michael; Bell, Alexander; Álvarez-Alonso, María-Teresa; Álvarez García, Daniel; Aparicio del Moral, Beatriz; Atiénzar, Julia; Ayoub, Daniel; Bailén, Francisco Javier; Bailón Martínez, Eduardo; Balaguer Jiménez, Maria; Barthol, Peter; Bayon Laguna, Montserrat; Bellot Rubio, Luis R.; Bergmann, Melani; Blanco Rodríguez, Julian; Bochmann, Jan; Borrero, Juan Manuel; Campos-Jara, Antonio; Castellanos Durán, Juan Sebastián; Cebollero, María; Conde Rodríguez, Aitor; Deutsch, Werner; Eaton, Harry; Fernández-Medina, Ana Belen; Fernandez-Rico, German; Ferreres, Agustin; García, Andrés; García Alarcia, Ramón María; García Parejo, Pilar; Garranzo-García, Daniel; Gasent Blesa, José Luis; Gerber, Karin; Germerott, Dietmar; Gilabert Palmer, David; Gizon, Laurent; Gómez Sánchez-Tirado, Miguel Angel; González-Bárcena, David; Gonzalo Melchor, Alejandro; Goodyear, Sam; Hara, Hirohisa; Harnes, Edvarda; Heerlein, Klaus; Heidecke, Frank; Heinrichs, Jan; Hernández Expósito, David; Hirzberger, Johann; Hoelken, Johannes; Hyun, Sangwon; Iglesias, Francisco A.; Ishikawa, Ryohtaroh T.; Jeon, Minwoo; Kawabata, Yusuke; Kolleck, Martin; Laguna, Hugo; Lomas, Julian; López Jiménez, Antonio C.; Manzano, Paula; Matsumoto, Takuma; Mayo Turrado, David; Meierdierks, Thimo; Meining, Stefan; Monecke, Markus; Morales-Fernández, José Miguel; Moreno Mantas, Antonio Jesús; Moreno Vacas, Alejandro; Müller, Marc Ferenc; Müller, Reinhard; Naito, Yoshihiro; Nakai, Eiji; Núñez Peral, Armonía; Oba, Takayoshi; Palo, Geoffrey; Pérez-Grande, Isabel; Piqueras Carreño, Javier; Preis, Tobias; Przybylski, Damien; Quintero Noda, Carlos; Ramanath, Sandeep; Ramos Más, Jose Luis; Raouafi, Nour; Rivas-Martínez, María-Jesús; Rodríguez Martínez, Pedro; Rodríguez Valido, Manuel; Ruiz Cobo, Basilio; Sánchez Rodríguez, Antonio; Sanchez Toledo, Mariano; Sánchez Gómez, Antonio; Sanchis Kilders, Esteban; Sant, Kamal; Santamarina Guerrero, Pablo; Schulze, Erich; Shimizu, Toshifumi; Silva-López, Manuel; Singh, Kunal; Siu-Tapia, Azaymi L.; Sonner, Thomas; Staub, Jan; Strecker, Hanna; Tobaruela, Angel; Torralbo, Ignacio; Tritschler, Alexandra; Tsuzuki, Toshihiro; Uraguchi, Fumihiro; Volkmer, Reiner; Vourlidas, Angelos; Vukadinović, Dušan; Werner, Stephan; Zerr, AndreasIn July 2024, SUNRISE completed its third successful science flight. The SUNRISE III observatory had been upgraded significantly after the two previous successful flights in 2009 and 2013, to tackle the most recent science challenges concerning the solar atmosphere. Three completely new instruments focus on the small-scale physical processes and their complex interaction from the deepest observable layers in the photosphere up to chromospheric heights. Previously poorly explored spectral regions and lines are exploited to paint a three-dimensional picture of the solar atmosphere with unprecedented completeness and level of detail. The full polarimetric information is captured by all three instruments to reveal the interaction between the magnetic fields and the hydrodynamic processes. Two slit-based spectropolarimeters, the SUNRISE UV Spectropolarimeter and Imager (SUSI) and the SUNRISE Chromospheric Infrared spectro-Polarimeter (SCIP), focus on the near-ultraviolet (309 – 417 nm) and the near-infrared (765 – 855 nm) regions respectively, and the imaging spectropolarimeter Tunable Magnetograph (TUMAG) simultaneously obtains maps of the full field-of-view of 46×46 Mm2 in the photosphere and the chromosphere in the visible (525 and 517 nm). The instruments are operated in an orchestrated mode, benefiting from a new Image Stabilization and Light Distribution unit (ISLID), with the Correlating Wavefront Sensor (CWS) providing the autofocus control and an image stability with a root-mean-square value smaller than 0.005". A new gondola was constructed to significantly improve the telescope pointing stability, required to achieve uninterrupted observations over many hours. SUNRISE III was launched successfully on 10 July 2024, from the Esrange Space Center of the Swedish Space Corporation near Kiruna (Sweden). It reached the landing site between the Mackenzie River and the Great Bear Lake in Canada after a flight duration of 6.5 days. In this paper, we give an overview of the SUNRISE III observatory and its instruments. © The Author(s) 2025Open Access funding enabled and organized by Projekt DEAL. SUNRISE III is supported by funding from the Max-Planck-Förderstiftung (Max Planck Foundation), NASA under Grant
#80NSSC18K0934 and #80NSSC24M0024 (“Heliophysics Low Cost Access to Space’ program), and the
ISAS/JAXA Small Mission-of-Opportunity program and JSPS KAKENHI JP18H05234/JP23H01220. This
research has received financial support from the European Union’s Horizon 2020 research and innovation
program under grant agreement No. 824135 (SOLARNET) and No. 101097844 (WINSUN) from the European Research Council (ERC). It has also been funded by the Deutsches Zentrum für Luft- und Raumfahrt
e.V. (DLR, grant no. 50 OO 1608). The Spanish contributions have been funded by the Spanish MCIN/AEI
under projects RTI2018-096886-B-C5, and PID2021-125325OB-C5, and from “Center of Excellence Severo
Ochoa” awards to IAA-CSIC (SEV-2017-0709, CEX2021-001131-S), all co-funded by European REDEF
funds, “A way of making Europe”.
D. Orozco Suárez acknowledges financial support from a Ramón y Cajal fellowship. The contributions
of J. Hölken, D. Vukadinovic, E. Harnes and K. Sant have been supported by the International Max Planck ´
Research School for Solar System Science at the University of Göttingen (IMPRS), Germany. F. A. Iglesias
is a member of the “Carrera del Investigador Científico” of CONICET and supported by MPS through the
Max Planck Partner Group between MPS and the University of Mendoza, Argentina. The research activities
and the flight operation of the SCIP team members, R. T. Ishikawa, M. Kubo, Y. Kawabata, and T. Oba, have
been supported from the JSPS KAKENHI grants No. 23KJ0299, No. 24K07105, No. 23K13152, and No.
21K13972, respectively.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (SEV-2017-0709).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).Peer reviewe
Two lamprey Hedgehog genes share non-coding regulatory sequences and expression patterns with gnathostome Hedgehogs.
No full textInternational audienceHedgehog (Hh) genes play major roles in animal development and studies of their evolution, expression and function point to major differences among chordates. Here we focused on Hh genes in lampreys in order to characterize the evolution of Hh signalling at the emergence of vertebrates. Screening of a cosmid library of the river lamprey Lampetra fluviatilis and searching the preliminary genome assembly of the sea lamprey Petromyzon marinus indicate that lampreys have two Hh genes, named Hha and Hhb. Phylogenetic analyses suggest that Hha and Hhb are lamprey-specific paralogs closely related to Sonic/Indian Hh genes. Expression analysis indicates that Hha and Hhb are expressed in a Sonic Hh-like pattern. The two transcripts are expressed in largely overlapping but not identical domains in the lamprey embryonic brain, including a newly-described expression domain in the nasohypophyseal placode. Global alignments of genomic sequences and local alignment with known gnathostome regulatory motifs show that lamprey Hhs share conserved non-coding elements (CNE) with gnathostome Hhs albeit with sequences that have significantly diverged and dispersed. Functional assays using zebrafish embryos demonstrate gnathostome-like midline enhancer activity for CNEs contained in intron2. We conclude that lamprey Hh genes are gnathostome Shh-like in terms of expression and regulation. In addition, they show some lamprey-specific features, including duplication and structural (but not functional) changes in the intronic/regulatory sequences
Cloning and expression analysis of an inducible HSP70 gene from tilapia fish
No full textpeer reviewedWe isolated and characterized the tilapia (Oreochromis mossambicus) HSP70 gene, highly homologous to other HSP70 genes. A dramatic increase of tilapia HSP70 mRNA levels was observed after heat shock of whole animals in all organs tested. Reporter constructs were tested for transient expression in carp cells and in microinjected zebrafish embryos. The entire isolated regulatory region (-851/+157) was able to mediate heat shock inducible expression of the reporter gene, with no preference for a particular tissue. Our studies represent the first transcriptional analysis of a HSP70 promoter from fish, revealing a powerful tool to direct controlled, tissue-independent gene expression in fish
Representação, visualização e manipulação de dados médicos tridimensionais: um estudo sobre as bases da simulação cirúrgica imersiva
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação.Dados tridimensionais referentes a pacientes são utilizados em diversos setores médico-hospitalares, fornecendo embasamento à diagnósticos e orientação durante procedimentos cirúrgicos. No entanto, apesar de bastante úteis estes dados são bastante inflexíveis, não permitindo que o usuário interaja com estes ou os manipule. O emprego de técnicas de computação gráfica e realidade virtual para a representação destes dados sanaria estas dificuldades, gerando representações indivíduais e adaptadas para cada paciente e permitindo a realização de planejamentos cirúrgicos e cirurgias auxiliadas por computador, dentre outras possibilidades. A representação destes dados e as formas de manipulação devem conter um conjunto de elementos e obedecer alguns requisitos para que se obtenha realismo nas aplicações, caso contrário, o emprego destas técnicas não traria grandes vantagens. Analisando os elementos e requisitos a serem obedecidos, é construído um grafo de dependências que mostra as técnicas e estruturas computacionais necessárias para a obtenção de ambientes virtuais imersivos realistas. Tal grafo demonstra as estruturas de dados para representação de sólidos como peça chave para este tipo de aplicativos. Para suprir as necessidades destes, é apresentada uma estrutura de dado capaz de representar uma vasta classe de topologias espaciais, além de permitir rápido acesso a elementos e suas vizinhanças, bem como métodos para a construção de tal estrutura. É apresentada, também, uma aplicação para mensuração de artérias utilizando a estrutura e os métodos previamente mencionados e os resultados por obtidos por estes
The Sunrise Ultraviolet Spectropolarimeter and Imager : Instrument Description
No full textPublisher Copyright: © The Author(s) 2025.The third science flight of the balloon-borne solar observatory Sunrise carries three entirely new post-focus science instruments with spectropolarimetric capabilities, concurrently covering an extended spectral range from the near ultraviolet to the near infrared. Sampling a larger height range, from the low photosphere to the chromosphere, with the sub-arcsecond resolution provided by the 1-m Sunrise telescope, is key in understanding critical small-scale phenomena which energetically couple different layers of the solar atmosphere. The Sunrise UV Spectropolarimeter and Imager (SUSI) operates between 309 nm and 417 nm. A key feature of SUSI is its capability to record up to several hundred spectral lines simultaneously without the harmful effects of the Earth’s atmosphere. The rich SUSI spectra can be exploited in terms of many-line inversions. Another important innovation of the instrument is the synchronized 2D context imaging which allows to numerically correct the spectrograph scans for residual optical aberrations. In this work we describe the main design aspects of SUSI, the instrument characterization and testing, and finally its operation, expected performance and data products.Peer reviewe
Iowa History and Culture : A Bibliography of Materials Published Between 1952 and 1986, 1989
No full textThis bibliography was compiled by two reference librarians, Patricia Dawson and David Hudson with the goal of making it easier of tracking down material on Iowa history and culture. This supplements the Iowa History Reference Guide published in 1952 by William Petersen
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