5,005 research outputs found
The power to nudge can we democratise choice environments?
No full textGovernments around the world have adopted ‘nudge’ strategies to change public behaviours and so implement policy goals. For some commentators, this creates concerns about transparency and democratic control. However, writes Andreas T. Schmidt (University of Groningen), within an environment where private companies frequently adopt nudge strategies, public policy nudges need not have greater implications for democracy and transparency than other forms of government intervention, and can be one tool in exerting democratic control over private sector nudge tactics
Nuisances forestières et perturbations naturelles dans les pays rhénans méridionaux par Schmidt (Albert), Falk (Karsten), Herforth (Andreas), Müller (Vera), Papajewski (Winfried), Schulte (Hilde)
No full textWackermann Gabriel. Nuisances forestières et perturbations naturelles dans les pays rhénans méridionaux par Schmidt (Albert), Falk (Karsten), Herforth (Andreas), Müller (Vera), Papajewski (Winfried), Schulte (Hilde). In: Annales de Géographie, t. 97, n°539, 1988. p. 111
Mathematics of the quantum Zeno effect
No full textWe present an overview of the mathematics underlying the quantum Zeno effect. Classical, functional analytic results are put into perspective and compared with more recent ones. This yields some new insights into mathematical preconditions entailing the Zeno paradox, in particular a simplified proof of Misra's and Sudarshan's theorem. We empahsise the complex-analytic structures associated to the issue of existence of the Zeno dynamics. On grounds of the assembled material, we reason about possible future mathematical developments pertaining to the Zeno paradox and its counterpart, the anti-Zeno paradox, both of which seem to be close to complete characterisations. PACS-Klassifikation: 03.65.Xp, 03.65Db, 05.30.-d, 02.30.T . See the corresponding presentation: Schmidt, Andreas U.: "Zeno Dynamics of von Neumann Algebras" and "Zeno Dynamics in Quantum Statistical Mechanics
Computing Tutte Paths
Full text linkTutte paths are one of the most successful tools for attacking problems on long cycles in planar graphs. Unfortunately, results based on them are non-constructive, as their proofs inherently use an induction on overlapping subgraphs and these overlaps prevent any attempt to bound the running time by a polynomial.
For special cases however, computational results of Tutte paths are known: For 4-connected planar graphs, Tutte paths are in fact Hamiltonian paths and Chiba and Nishizeki [N. Chiba and T. Nishizeki, 1989] showed how to compute such paths in linear time. For 3-connected planar graphs, Tutte paths have a significantly more complicated structure, and it has only recently been shown that they can be computed in polynomial time [A. Schmid and J. M. Schmidt, 2015]. However, Tutte paths are defined for general 2-connected planar graphs and this is what most applications need. In this unrestricted setting, no computational results for Tutte paths are known.
We give the first efficient algorithm that computes a Tutte path (in this unrestricted setting). One of the strongest existence results about such Tutte paths is due to Sanders [D. P. Sanders, 1997], which allows one to prescribe the end vertices and an intermediate edge of the desired path. Encompassing and strengthening all previous computational results on Tutte paths, we show how to compute such a special Tutte path efficiently. Our method refines both, the existence results of Thomassen [C. Thomassen, 1983] and Sanders [D. P. Sanders, 1997], and avoids that the subgraphs arising in the inductive proof intersect in more than one edge by using a novel iterative decomposition along 2-separators. Finally, we show that our algorithm runs in time O(n^2)
Gordius gonzalezi Schmidt-Rhaesa & Martínez, 2016, n. sp.
No full text<i>Gordius gonzalezi</i> n. sp. <p> <b>Type locality.</b> Guijo de Sta. Bárbara. Comarca de La Vera, arroyo de la Gazapierna. Sierra de los Tormantos, 759 m, Cáceres, Extremadura, Spain, 40°9´0.57´´N / 5°40´0.30´´W.</p> <p> <b>Holotype.</b> One male, Zoological Museum Hamburg ZMH V13368</p> <p> <b>Paratype.</b> One male, Zoological Museum Hamburg ZMH V13369</p> <p> <b>Etymology.</b> The species name “ <i>gonzalezi</i> ” honours Prof. Dr. Marcos González from the Universidad de Santiago de Compostela, advisor of the second author.</p> <p> <b>Further information.</b> Collected on July 23, 2010 in a light trap together with a cricket, which might have been the host. Collected by J. Martínez and M. González.</p> <p> <b>Description.</b> The specimens are 235 mm (holotype) and 220 mm (paratype) long, and both measure 1 mm in diameter. They are a medium shade of brown in color and have a white cap and a dark collar at the anterior end, as is usual in the genus <i>Gordius</i>. There is a faint dorsal and a ventral longitudinal line of darker coloration, and white spots are present on the cuticle.</p> <p>SEM investigation shows that the cuticle forms folds or cords of irregular structure (Fig. 1 C). These cords have alternating broader and narrower regions and they are arranged perpendicular to the longitudinal axis of the worm. Under higher magnification their surface is rough and composed of fibres (Fig. 1 D, E). Abundant spine-like extensions are present on the cuticle, estimated to be a few micrometers in length (Fig. 1 A–D). They occur on almost the entire cuticle with an irregular distribution (Fig. 1 D), but in a regular pattern on either the ventral or the dorsal side (Fig. 1 B, C). There they occur in two lines on both sides of a 60 µm broad band of cuticle that is devoid of spines (Fig. 1 B, C). The region between the lines of spines is structured into polygonal structures, mostly hexagons of irregular shape and size of their sides. The spines have a diameter of about 5µm on their base and decrease towards their apex (Fig. 1 E, F). The spines resemble the cuticular fine structure and have a fibrillary appearance rather than a smooth surface.</p> <p>The posterior end has a parabolic postcloacal crescent that extends onto the tail lobes (Fig. 2 A, C). The cloacal opening could not be observed and is probably covered by dirt or other material. The spine-like extensions described above extend in the posterior end onto the outer side of the tail lobes (Fig. 2 A–C). In the holotype, further spines are present on the inner side of the tail lobes (Fig. 2 C-E). These spines are more slender than the “spine-like extensions” and are curved apically (Fig. 2 E). They were not observed in the paratype.</p> <p> <b>Remarks</b>. In the majority of freshwater nematomorphs the cuticle is formed into elevated substructures called areoles. These may be flat polygonal structures or may be more elevated and more diverse in structure. In the genus <i>Gordius</i>, only flat areoles are present or the cuticle is smooth. The observed cords on the cuticle might represent strongly modified areoles, because of their alternating diameter. There is some resemblance to the cuticular pattern as described for <i>G. plicatissimus</i>, figured by SEM for an undescribed species named “ cf. <i>plicatissimus</i> ” by Schmidt-Rhaesa (2010). The fibrous substructure of the cuticle has been observed by SEM investigation of several specimens (see Schmidt-Rhaesa 2010) and it is still not clear if this represents the native surface of the cuticle or if there has been some ageing or abrasion of a cuticular surface layer that creates this fibrous character.</p> <p> Structures described here as spines are present on few other <i>Gordius</i> species. Spine-like structures have been reported on two Asian species (from Uzbekistan and Tajikistan), <i>G. bivittatus</i> and <i>G. t e s t a c eu s</i>, both described by Kirjanova (1950), and on two South American species, <i>G. deltaensis</i> and <i>G. spinosus</i>, both described by De Miralles & De Villalobos (1996a, b). In all four species, the documentation is not optimal, but the presence of spines is reported as being scarce and a regular arrangement into lines was never reported. Therefore we assume that the specimens represent a new species of the genus <i>Gordius</i>.</p>Published as part of <i>Schmidt-Rhaesa, Andreas & Martínez, Jesús, 2016, Gordius gonzalezi, a new species of horsehair worms (Nematomorpha) from Spain, pp. 63-67 in Zootaxa 4103 (1)</i> on pages 64-66, DOI: 10.11646/zootaxa.4103.1.6, <a href="http://zenodo.org/record/271176">http://zenodo.org/record/271176</a>
The soda lake—mesosaline halite lake transition in the Ries impact crater basin (drilling Löpsingen 2012, Miocene, southern Germany)
No full textLacustrine sediments of impact craters form valuable climate archives, although chemical evolution and changes in the catchment area potentially superimpose, distort, or obliterate primary climate signals. The 15 Ma Nördlinger Ries in southern Germany, one of the most intensively studied terrestrial impact structures, harbors a well-preserved but controversially interpreted lacustrine sedimentary fill. While earlier studies proposed a climate-driven development from a playa to a mesosaline soda lake (Units A and B), which then decreased in salinity (Units C and D), new investigations suggest a chemical evolution from a playa and soda lake (Units A–C) to a mesosaline halite lake (Unit D), which then turned into a hypersaline halite lake, until an outlet formed. However, problems in the stratigraphic correlation of basin center and margin sediments impeded the recognition of the hypothetical soda to halite lake transition to date. A new drilling in the central crater now provides a solution for the problem. Unit C still comprises analcime-rich dolomite marl with reversely correlated δ13C and δ18O values, thereby reflecting a shallow, highly alkaline, saline meromictic lake (Na–Mg–CO3–SO4). In turn, Unit D is characterized by a change to cycles composed of lignite, diatomite, claystone, marl, and limestone. Gypsum pseudomorphs at the cycle tops indicate saline lake water (Na–Mg–Cl–SO4) with increased Ca2+ concentrations. Reworked, previously aragonitic, green algal tubes prove that early parts of Unit D sediments formed contemporaneously to basin margin green algal bioherms, contrary to previous assumptions. Therefore, the change from a highly alkaline soda lake to a mesosaline halite lake reflects increasing influx of waters from the Bunte Breccia into the lake, while suevite-derived weathering solutions decreased. Low-salinity conditions during Unit D are temporary phases during lake-level rise at the beginning of short-term cycles, whereas stable oxygen isotope ratios indicate meso- to hypersaline conditions at cycle tops. However, the long-term increase in salinity leading to continuous hypersaline conditions is only preserved in carbonates at the crater rim
The Mt. Mulga barite-magnetite-copper-gold mineralisation, Olary Domain, South Australia
No full textMartin Griessmann, Andreas Schmidt Mumm, Thomas Seifert and Colin Cono
Der Einfluss von Strukturen und Reaktionen an der Wasser/Mineral-Grenzfläche auf die Radionuklidmobilität
Full text linkDie Langzeitsicherheitsanalyse für ein Endlager für nukleare Abfälle bedarf einer eingehenden Beschreibung der Mobilität von Radionukliden im Nah- und Fernfeld des Endlagers. Da extrem lange Zeiträume von bis zu einer Million Jahren abgebildet werden müssen, muss diese Beschreibung auf einem molekularen Prozessverständnis beruhen. Nur dann ist eine unbegrenzte zeitliche Extrapolation zulässig. Die wichtigsten Rückhalteprozesse finden an der Wasser/Mineralgrenzfläche statt, wobei in einem realen Endlager sehr viele primäre und sekundäre Mineralphasen vorhanden sind, mit denen die Radionuklide wechselwirken können. Zudem stehen eine Vielzahl verschiedener Reaktionsmechanismen zur Verfügung – innersphärische oder außersphärische Sorption, struktureller Einbau, Oberflächenfällung etc. – die sich hinsichtlich ihrer Rückhaltefähigkeit deutlich unterscheiden. Somit muss auf hochsensitive Methoden zurückgegriffen werden, die in der Lage sind, selektiv Informationen über die relevanten Radionuklide innerhalb der Grenzschicht zu liefern.
Die in dieser Arbeit hauptsächlich verwendeten Methoden, die zeitaufgelöste Laser-induzierte Fluoreszenzspektroskopie (TRLFS), und die Oberflächenröntgenbeugungsmethoden crystal truncation rod (CTR) Messung und resonant anomalous X-ray reflectivity (RAXR), haben sich als effiziente Werkzeuge zur Ermittlung struktureller und Speziationsdaten erwiesen. So konnte im Rahmen dieser Arbeit die Wechselwirkung der Radionuklide U, Pu, Am und Cm mit verschiedenen Mineralphasen aufgeklärt, sowie die Abhängigkeit dieser Reaktionen von der Lösungszusammensetzung beschrieben werden.:1 Einleitung 9
1.1 Zeitaufgelöste laser-induzierte Fluoreszenzspektroskopie 12
1.2 Oberflächenröntgenbeugung 18
2 Spektroskopische Charakterisierung von Einbauprozessen 21
2.1 Biswas S, Steudtner R, Schmidt M, McKenna C, Vintró LL 25
Twamley B, et al. An investigation of the interactions of Eu3+ and Am3+ with uranyl minerals: implications for the storage of spent nuclear fuel. Dalton Transactions. 2016; 45(15):6383-93.
2.2 Schmidt M, Heck S, Bosbach D, Ganschow S, Walther 36
C, Stumpf T. Characterization of powellite-based solid solutions by site-selective time resolved laser fluorescence spectroscopy. Dalton Transactions. 2013;42(23):8387 - 93.
2.3 Hellebrandt SE, Hofmann S, Jordan N, Barkleit A, Schmidt M. 43
Incorporation of Eu(III) into Calcite under recrystallization conditions. Scientific Reports. 2016;6:33137.
2.4 Johnstone EV, Hofmann S, Cherkouk A, Schmidt M. 53
Study of the Interaction of Eu3+ with Microbiologically Induced Calcium Carbonate Precipitates using TRLFS. Environmental Science & Technology. 2016;50(22):12411-20.
3 Oberflächeninduzierte Kondensationsreaktionen 63
3.1 Lee SS, Schmidt M, Fister TT, Nagy KL, Sturchio NC, Fenter P. 65
Structural Characterization of Aluminum (Oxy)hydroxide Films at the Muscovite (001)–Water Interface. Langmuir. 2016; 32(2):477-86.
3.2 Hellebrandt S, Lee SS, Knope KE, Lussier AJ, Stubbs JE, Eng 75
PJ, et al. Cooperative effects of adsorption, reduction, and polymerization observed for hexavalent actinides on the muscovitebasal plane. Langmuir. 2016; 32(41):10473-82.6
3.3 Schmidt M, Lee SS, Wilson RE, Knope KE, Bellucci F, Eng 85
PJ, et al. Surface-Mediated Formation of Pu(IV) Nanoparticles at the Muscovite-Electrolyte Interface. Environmental Science & Technology. 2013;47(24):14178-84.
4 Elektrolyteffekte auf Oberflächenprozesse 92
4.1 Lee SS, Schmidt M, Laanait N, Sturchio NC, Fenter P. 94
Investigation of Structure, Adsorption Free Energy, and Overcharging Behavior of Trivalent Yttrium Adsorbed at the Muscovite (001)–Water Interface. The Journal of Physical Chemistry C. 2013;117(45):23738-49.
4.2 Schmidt M, Hellebrandt S, Knope KE, Lee SS, Stubbs JE, 106 Eng PJ, et al. Effects of the Background Electrolyte on Th(IV) Sorption to Muscovite Mica. Geochimica et Cosmochimica Acta. 2015;165:280-93.
4.3 Hofmann S, Voïtchovsky K, Schmidt M, Stumpf T. Trace 120 concentration – Huge impact: Nitrate in the calcite/Eu(III) system. Geochimica et Cosmochimica Acta. 2014;125:528-38.
4.4 Hofmann S, Voïtchovsky K, Spijker P, Schmidt M, Stumpf 131
T. Visualising the molecular alteration of the calcite (104)–water interface by sodium nitrate. Scientific Reports. 2016; 6:21576.
5 Schlussfolgerungen 142
Literatur 146The safety assessment of a nuclear waste disposal site requires the accurate description of the radionuclides’ mobility in the near and far field of the site. This description must rely on molecular level understanding of the occurring processes to allow extrapolation for time frames of up to one million years. The most important retention mechanisms take place at the water/mineral interface. A disposal site will contain a large number of mineral phases, both as primary and secondary minerals. Moreover, a large number of potential reaction pathways is conceivable, and must be investigated: inner and outer sphere sorption, structural incorporation, surface precipitation, etc. As these mechanisms will differ significantly in their retention potential, it is crucial to be able to differentiate between them. Hence, the need arises for analytical techniques capable of providing selective information about radionuclides at the water/mineral interface.
This work employs time-resolved laser-induced fluorescence spectroscopy (TRLFS), as well as the surface X-ray diffraction techniques crystal truncation rod (CTR) measurements and resonant anomalous X-ray reflectivity (RAXR) as efficient tools to obtain both structural and speciation data from these systems. Following this approach, the interaction of the radionuclides U, Pu, Am, and Cm with various mineral phases could be elucidated, while also characterizing the dependence of these reactions on the composition of the aqueous solution.:1 Einleitung 9
1.1 Zeitaufgelöste laser-induzierte Fluoreszenzspektroskopie 12
1.2 Oberflächenröntgenbeugung 18
2 Spektroskopische Charakterisierung von Einbauprozessen 21
2.1 Biswas S, Steudtner R, Schmidt M, McKenna C, Vintró LL 25
Twamley B, et al. An investigation of the interactions of Eu3+ and Am3+ with uranyl minerals: implications for the storage of spent nuclear fuel. Dalton Transactions. 2016; 45(15):6383-93.
2.2 Schmidt M, Heck S, Bosbach D, Ganschow S, Walther 36
C, Stumpf T. Characterization of powellite-based solid solutions by site-selective time resolved laser fluorescence spectroscopy. Dalton Transactions. 2013;42(23):8387 - 93.
2.3 Hellebrandt SE, Hofmann S, Jordan N, Barkleit A, Schmidt M. 43
Incorporation of Eu(III) into Calcite under recrystallization conditions. Scientific Reports. 2016;6:33137.
2.4 Johnstone EV, Hofmann S, Cherkouk A, Schmidt M. 53
Study of the Interaction of Eu3+ with Microbiologically Induced Calcium Carbonate Precipitates using TRLFS. Environmental Science & Technology. 2016;50(22):12411-20.
3 Oberflächeninduzierte Kondensationsreaktionen 63
3.1 Lee SS, Schmidt M, Fister TT, Nagy KL, Sturchio NC, Fenter P. 65
Structural Characterization of Aluminum (Oxy)hydroxide Films at the Muscovite (001)–Water Interface. Langmuir. 2016; 32(2):477-86.
3.2 Hellebrandt S, Lee SS, Knope KE, Lussier AJ, Stubbs JE, Eng 75
PJ, et al. Cooperative effects of adsorption, reduction, and polymerization observed for hexavalent actinides on the muscovitebasal plane. Langmuir. 2016; 32(41):10473-82.6
3.3 Schmidt M, Lee SS, Wilson RE, Knope KE, Bellucci F, Eng 85
PJ, et al. Surface-Mediated Formation of Pu(IV) Nanoparticles at the Muscovite-Electrolyte Interface. Environmental Science & Technology. 2013;47(24):14178-84.
4 Elektrolyteffekte auf Oberflächenprozesse 92
4.1 Lee SS, Schmidt M, Laanait N, Sturchio NC, Fenter P. 94
Investigation of Structure, Adsorption Free Energy, and Overcharging Behavior of Trivalent Yttrium Adsorbed at the Muscovite (001)–Water Interface. The Journal of Physical Chemistry C. 2013;117(45):23738-49.
4.2 Schmidt M, Hellebrandt S, Knope KE, Lee SS, Stubbs JE, 106 Eng PJ, et al. Effects of the Background Electrolyte on Th(IV) Sorption to Muscovite Mica. Geochimica et Cosmochimica Acta. 2015;165:280-93.
4.3 Hofmann S, Voïtchovsky K, Schmidt M, Stumpf T. Trace 120 concentration – Huge impact: Nitrate in the calcite/Eu(III) system. Geochimica et Cosmochimica Acta. 2014;125:528-38.
4.4 Hofmann S, Voïtchovsky K, Spijker P, Schmidt M, Stumpf 131
T. Visualising the molecular alteration of the calcite (104)–water interface by sodium nitrate. Scientific Reports. 2016; 6:21576.
5 Schlussfolgerungen 142
Literatur 14
Planetary transit observations at the University Observatory Jena: XO-1b and TrES-1
No full textWe report on observations of transit events of the transiting planets XO-1b and TrES-1 with a 25 cm telescope of the University Observatory Jena. With the transit timings for XO-1b from all 50 available XO, SuperWASP, Transit Light Curve (TLC)-Project- and Exoplanet Transit Database (ETD)-data, including our own I-band photometry obtained in March 2007, we find that the orbital period is P = (3.941501 +/- 0.000001) d, a slight change by similar to 3 s compared to the previously published period. We present new ephemeris for this transiting planet. Furthermore, we present new R-band photometry of two transits of TrES-1. With the help of all available transit times from literature this allows us to refine the estimate of the orbital period: P = (3.0300722 +/- 0.0000002) d. Our observations will be useful for future investigations of timing variations caused by additional perturbing planets and/or stellar spots and/or moons. (C) 2009 WILEY-VCH Verlag GmbH &Co. KGaA. Weinhei
Author Correction: Insights from serial cardiovascular magnetic resonance imaging show early progress in diastolic dysfunction relates to impaired right ventricular deformation
No full text- …
