588 research outputs found
Probing the relationship between electromagnetic ion cyclotron waves and plasmaspheric plumes near geosynchronous orbit
No full textPlasmaspheric plumes created during disturbed geomagnetic conditions have been suggested as a major cause of increased occurrences of electromagnetic ion cyclotron (EMIC) waves at these times. We have catalogued occurrences of strong Pc1 EMIC waves from 1996 through 2003 at three automated geophysical observatories operated by the British Antarctic Survey at auroral zone latitudes in Antarctica (L = 6.28, 7.68, and 8.07) and have compared them to the occurrence of plasmaspheric plumes in space, using simultaneous data from the Magnetospheric Plasma Analyzer on the Los Alamos National Laboratory 1990-095 spacecraft, in geosynchronous orbit at the same magnetic longitude. A superposed epoch analysis of these data was conducted for several categories of disturbed geomagnetic conditions, including magnetic storms, high-speed streams, and storm sudden commencements. We found only a weak correspondence between the occurrence of strong Pc1 waves observed on the ground and either plasmaspheric plumes or intervals of extended plasmasphere at geosynchronous orbit before, during, or after the onset of any of these categories. Strong Pc1 activity peaked near or slightly after local noon during all storm phases, consistent with equatorial observations by the Active Magnetospheric Particle Tracer Explorers/Charge Composition Explorer satellite at these L shells. The highest Pc1 occurrence probability was at or 1-2 days before storm onset and during the late recovery phase. Occurrence was lowest during the early recovery phase, consistent with the decrease in solar wind pressure often seen at this time. The peak at onset is consistent with earlier observations of waves in the outer magnetosphere stimulated by sudden impulses and magnetospheric compressions
Explaining Output Volatility: The Case of Taxation
No full textThis paper presents empirical evidence against the popular perception that macro volatility is exogenous. We obtain tax effects on macro aggregates in the stochastic neoclassical model. Taxes are shown to affect the second moment of output growth rates without affecting the first moment. Exploiting heterogeneity patterns in a panel of OECD countries, we estimate tax effects on macro volatility, explicitly modeling the unobserved variance process. We find a strong empirical link between taxes and output volatility. Accounting for non-stationarity of taxes and output volatility, we find empirical evidence of a cointegrating relationship.macroeconomic volatility, tax effects, continuous-time DSGE models
Three Medals by Leonhard Posch in the Zagreb Archaeological Museum Numismatic Collection
No full textAutor posvećuje pažnju nekim medaljama većih dimenzija, od lijevanog željeza, iz fundusa Numizmatičke zbirke Arheološkog muzeja u Zagrebu. Tri su medalje radovi poznatog austrijsko-njemačkog medaljera Leonharda Poscha, dok je autor četvrte medalje nepoznat.There are four cast-iron medals of large size from the early 19th c. in the Zagreb Archaeological Museum Numismatic Collection. They were catalogued by the Museum director Josip Brunšmid at the time he was compiling new inventories of the considerable collection, but he was unable to identify either the artist or the persons depicted on them. Only one of them, thanks to the inscription on the reverse of the medal, could be partly identified as a grand-duchess of Weimar:" N. VI —1 34/Er(lauchte?).Gr(oss):Herz(ogin) =/v(on)=/Weimar"( Fig. 3). These medals were not signed, therefore their author remained unknown for a long time. The quality of three of them shows they must have been modelled by an excellent medallist. The fourth medal, likewise unsigned, was made by a less skilled artist and thus both the person portrayed and the medallist will remain unknown for a while. As none of these medals were to be found in Major Mijat Sabljar's inventories from the fifties of the 19th c., they might have entered the collection during Don Šime Ljubič's tenure (1867.-1892.). In 2003 the director of the Berlin Numismatic Cabinet Dr. Wolfgang Steguweit presented the writer of this paper with the latest and fundamental book dealing with the oeuvre of the great Austrian Prussian master Leonhard Posch (Finsing, 7 November 1750 — Berlin, 21 June 1831), written by Anne Forschler Tarrasch. For several decades to come, this monograph will be the base for any further study of medals by Posch.
Going to through the vast catalogue, containing as many as 1038 works, three of the iron medals from Zagreb were finally identified. Three important persons in German history of the early 19th c. were portrayed on them 19. st. The first medal is one of several Posch's portraits of the patriotic Prussian queen Luise (Hannover, 10 March 1766 — Hohenzieritz, Strelitz, 19 July 1810, Fig. 1), the second of Marie Pavlovna (15 February 1786 — 23 June 1859), granddaughter of Catherine II the Great of Russia, the hereditary Grand Duchess of Saxonia-Weimar (Fig. 2) and the third is a medal with the portrait of the Prussian statesman Karl August Prince Hardenberg (Essenrode/ Hannover, 31 March 1750 — Genova, 26 November 1822; Fig. 3). None of the medals is dated, but from the aforesaid monograph we can find that the medal of Luise of Prussia was made in 1805, the Hardenberg medal in 1815 and the portrait medal of Marie Pavlovna in c. 1816.
As medallist L Posch was held in very high esteem. He was born on 7 November 1750 in Tyrol, Austria, at the Finsing hamlet (Haasberg, Zillertal). His great talent was discovered by Franz Xaver Nissl (1731 — 1804), an Austrian sculptor of the Baroque period. Posch then became an apprentice of another well-known sculptor of the period, Jonann Baptist Hagenauer (1732 — 1810) in Salzburg, with the financial support of Cardinal Archbishop Sigismund Christoph Count Schrattenbach of Salzburg. Having completed his study, Posch worked in Vienna (1774-1803), attracting the attention of Empress Maria Teresia, who commissioned him to make several sculptures for the Schonbrunn park. Because of poor health he had to abandon monumental sculpture and dedicate himself to small sculpture and medals. Thus in Vienna alone Posch modelled more than 150 portrait medallions. In 1803 he moved to Hamburg, and in 1804 to Berlin, where he remained until 1810, when, following the suggestions of the wellknown artist of the Empire era, Dominique Vivant Denon, he went to Paris. In Paris Posch stayed until Napoleon's fall in 1814. In the summer of 1814 he decided to return to Berlin, where he stayed until his death on 21 June 1831. He was active as professor of modelling with the mint and the china manufacture as well as the Prussian art foundry. Already in 1816 he enjoyed all the privileges of a member of the Academy, but only became a member several years later. His style of producing cast iron medals was imitated by many lesser artists (Fig. 4). The iron medals described are only a small part of the medal collection of the Zagreb Archaeological Museum Numismatic Collection, i.e. of the group of medals made in the Empire style during the early 19 c. There are c. 140 various specimens of such and the present author presented a paper dealing with them at a conference on Napoleonic medals, held in Udine, Italy, in 1997
A gain-of-function TBX20 mutation causes congenital atrial septal defects, patent foramen ovale and cardiac valve defects
No full textBackground: Ostium secundum atrial septal defects (ASDII) account for approximately 10percent of all congenital heart defects (CHD), and mutations in cardiac transcription factors, including TBX20, were identified as an underlying cause for ASDII. However, very little is known about disease penetrance in families and functional consequences of inherited TBX20 mutations. Methods: The coding region of TBX20 was directly sequenced in 170 ASDII patients. Functional consequences of one novel mutation were investigated by surface plasmon resonance, CD spectropolarymetry, fluorescence spectrophotometry, luciferase assay and chromatin immunoprecipitation. Results: We found a novel mutation in a highly conserved residue in the T-box DNA binding domain (I121M) segregating with CHD in a three generation kindred. Four mutation carriers revealed cardiac phenotypes in terms of cribriform ASDII, large patent foramen ovale or cardiac valve defects. Interestingly, tertiary hydrophobic interactions within the mutant TBX20 T-box were significantly altered leading to a more dynamic structure of the protein. Moreover, Tbx20-I121M resulted in a significantly enhanced transcriptional activity, which was further increased in the presence of co-transcription factors GATA4-5 and NKX2-5. Occupancy of DNA binding sites on target genes was also increased. Conclusions: We suggest that TBX20-I121M adopts a more fluid tertiary structure leading to enhanced interactions with cofactors and more stable transcriptional complexes on target DNA sequences. Our data, combined with that of others, suggest that human ASDII may be related to loss-of-function as well as gain-of-function TBX20 mutations.Arquizan C, 2001, STROKE, V32, P1563; Basson CT, 1997, NAT GENET, V15, P30, DOI 10.1038-ng0197-30; Biben C, 2000, CIRC RES, V87, P888; Bruneau BG, 2008, NATURE, V451, P943, DOI 10.1038-nature06801; Caputo S, 2005, EUR HEART J, V26, P2179, DOI 10.1093-eurheartj-ehi378; Coll M, 2002, STRUCTURE, V10, P343, DOI 10.1016-S0969-2126(02)00722-0; Garg V, 2003, NATURE, V424, P443, DOI 10.1038-nature01827; HAGEN PT, 1984, MAYO CLIN PROC, V59, P17; Hammer S, 2008, J CELL BIOCHEM, V104, P1022, DOI 10.1002-jcb.21686; Hirayama-Yamada K, 2005, AM J MED GENET A, V135A, P47, DOI 10.1002-ajmg.a.30684; Kasahara H, 2004, CARDIOVASC RES, V64, P40, DOI 10.1016-j.cardiores.2004.06.004; Kirk EP, 2007, AM J HUM GENET, V81, P280, DOI 10.1086-519530; Kirk EP, 2006, CIRC RES, V98, P651, DOI 10.1161-01.RES.0000209965.59312.aa; Liu CX, 2008, EUR J MED GENET, V51, P580, DOI 10.1016-j.ejmg.2008.09.001; Macindoe I, 2009, J MOL BIOL, V389, P606, DOI 10.1016-j.jmb.2009.04.056; Nemer Georges, 2006, Hum Mutat, V27, P293, DOI 10.1002-humu.9410; Ng PC, 2001, GENOME RES, V11, P863, DOI 10.1101-gr.176601; Posch MG, 2008, AM J MED GENET A, V146A, P251, DOI 10.1002-ajmg.a.32042; Postma AV, 2008, CIRC RES, V102, P1433, DOI 10.1161-CIRCRESAHA.107.168294; Qian L, 2008, P NATL ACAD SCI USA, V105, P19833, DOI 10.1073-pnas.0808705105; Ramensky V, 2002, NUCLEIC ACIDS RES, V30, P3894, DOI 10.1093-nar-gkf493; Stennard FA, 2005, DEVELOPMENT, V132, P4897, DOI 10.1242-dev.02099; Stennard FA, 2003, DEV BIOL, V262, P206, DOI 10.1016-S0012-1606(03)00385-3; Stennard FA, 2005, DEVELOPMENT, V132, P2451, DOI 10.1242-dev.01799; Wilmshurst PT, 2004, HEART, V90, P1315, DOI 10.1136-hrt.2003.025700; Yagi H, 2003, LANCET, V362, P1366, DOI 10.1016-S0140-6736(03)14632-631353
Natural Volatility, Welfare and Taxation
No full textCyclical components are analytically computed in a theoretical model of stochastic endogenous fluctuations and growth. Volatility is shown to depend on the speed of convergence of the cyclical component, the expected length of a cycle and on the altitude of the slump. Taxes affect these channels and can therefore explain cross-country differences and breaks over time in volatility. With exogenous sources of fluctuations, a special case of our model, decentralized factor allocation is efficient. With endogenous fluctuations and growth, decentralized factor allocation is inefficient and (time-invariant) taxes can (de-) stabilize the economy. No unambiguous link exists between volatility and welfare.endogenous fluctuations and growth, welfare analysis, taxation, stochasticcontinuous time model, poisson uncertainty
Gli strumenti a fiato nell'orchestra
No full textLezione-concerto organizzata in collaborazione tra Centro Teatro Universitario, Ferrara Musica e Facoltà di Lettere e Filosofia, nell'ambito della rassegna "Facoltà di Musica".
In programma:
G. Jacob, Partita per fagotto solo; O. Messiaen, Apper Interstellaire da Des Canyon aux Etolies; L. Berio, Sequenza per clarinetto; J. Françaix, Quintetto per fiati in mi maggiore op. 1
Guillaume Santana, fagotto; Sebastian Posch, corno; Jann Bossier, clarinetto; Mizuho Yoshii, oboe; Marc Thomas, clarinetto; Julia Gallego, flaut
Natural volatility, welfare and taxation
No full textCyclical components are analytically computed in a theoretical model of stochastic endogenous fluctuations and growth. Volatility is shown to depend on the speed of convergence of the cyclical component, the expected length of a cycle and on the altitude of the slump. Taxes affect these channels and can therefore explain cross-country differences and breaks over time in volatility. With exogenous sources of fluctuations, a special case of our model, decentralized factor allocation is efficient. With endogenous fluctuations and growth, decentralized factor allocation is inefficient and (time-invariant) taxes can (de-) stabilize the economy. No unambiguous link exists between volatility and welfare.Endogenous fluctuations and growth, welfare analysis, taxation, stochastic continuous time model, Poisson uncertainty
United Kingdom National Focal Centre report
No full textReport by the UK National Focal Centre (NFC) documenting the country’s submission of data and assessments
in response to the Coordination Centre for
Effects (CCE) Call for Data, issued in 2012
A semi-empirical dynamic soil acidification model for use in spatially explicit integrated assessment models for Europe
No full textA semi-empirical soil acidification model was developed for use in integrated assessment models on a European scale. The model simulates the time development of base saturation and aluminium concentration using an empirical relationship with pH. An accompanying data set was developed by overlaying European maps of soils, land use, climate and altitude followed by a procedure that aggragates the input data over soil-texture combinations in each EMEP 150 km x 150 km grid cell. Model tests show that themodel gives results comparable to the SMART model, although it overestimates initial base saturation in some areas with high acid input and simulates a faster recovery from acidification than SMART
Numerical Solution of Dynamic Equilibrium Models under Poisson Uncertainty
No full textWe propose a simple and powerful numerical algorithm to compute the transition process in continuous-time dynamic equilibrium models with rare events. In this paper we transform the dynamic system of stochastic differential equations into a system of functional differential equations of the retarded type. We apply the Waveform Relaxation algorithm, i.e., we provide a guess of the policy function and solve the resulting system of (deterministic) ordinary differential equations by standard techniques. For parametric restrictions, analytical solutions to the stochastic growth model and a novel solution to Lucas' endogenous growth model under Poisson uncertainty are used to compute the exact numerical error. We show how (potential) catastrophic events such as rare natural disasters substantially affect the economic decisions of households.continuous-time DSGE, Poisson uncertainty, waveform relaxation
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