An introduction to derived (algebraic) geometry

These are notes from an introductory lecture course on derived geometry, given by the second author, mostly aimed at an audience with backgrounds in geometry and homological algebra. The focus is on derived algebraic geometry, mainly in characteristic $0$, but we also see the tweaks which extend most of the content to analytic and differential settings. The main motivating applications given are in moduli theory, with practically applicable representability theorems.Comment: 93pp; v2 minor changes; v3 minor additions, mostly reference

The pressure medium as a solid-state oxygen buffer

We present a simple method to buffer oxygen fugacity at high pressures and high temperatures where the traditional 'double capsule' method is inappropriate. The pressure medium is doped with a metal which partially reacts with the free oxygen in the pore spaces of the, cell. The resultant finely intergrown metal-metal oxide assemblage buffers the oxygen fugacity in the sample as long as the capsule and furnace materials are oxygen permeable

Gefäßchirurgische Ausbildung in endovaskulären Techniken am Universitären Gefäßzentrum Aarau-Basel

Zusammenfassung: Endovaskuläre Techniken gewinnen in der gefäßchirurgischen Praxis zunehmend an Bedeutung und müssen deshalb in die Ausbildung integriert werden. Die gefäßchirurgische Ausbildung in der Schweiz umfasst nach neuen Richtlinien das Beherrschen von endovaskulären Techniken und fordert die Durchführung von mindestens 50 Katheterisierungen/Angiographien und 25 interventionellen Eingriffen. An unserer Klinik stützt sich die interventionelle Ausbildung auf verschiedene Pfeiler. Wichtig ist eine gute interdisziplinäre Zusammenarbeit mit der Abteilung für interventionelle Radiologie, die konsequente Durchführung der Kontrollangiographie bei offenen Operationen und Virtual-Reality-Training. Unter diesen Bedingungen ist eine Ausbildung möglich, die den schweizerischen Richtlinien entspricht. Verbesserungspotenzial sehen wir v.a. in festen Kooperationsvereinbarungen mit der interventionellen Radiologi

Relative importance of fluvial and glacial erosion in shaping the Chandra Valley, western Himalaya, India

Abstract HKT-ISTP 2013 B

Holocene pisoliths and encrustations associated with spring-fed surface pools, Pastos Grandes

ABSTRACT Calcite pisoliths, with diameters ranging from 1 fo 200 mm, are forming now on the surface of a playa (salar) in the Andean Altiplano (4500 m above MSL) of Bolivia. They are associated with active or recently active hot springs (20-75°C) which flow onto the playa surface. Encrustations of pieces of an older caliche-type ' crust, of pisoliths, of indurated mud and of older concretions are also found as well as series of small (1-3 cm high) sinter terraces (rimstone dams). Arborescent concretions and overgrowths are common and they are reminiscent of drip-stone textures. Water analyses demonstrate that calcite supersaturation (about twenty times) occurs mainly through CO, loss, with photosynthesis by algae and degassing the main removal mechanisms. The two available analyses indicate slight evaporation and a calcium loss between spring and pool of 2.3 mmol per litre of water. It is thought that the hot springs pick up much of their solute load from the playa sediments. The closest analogues to these deposits have been reported from caves (cave pearls and concretions). Although the depositional ptocesses may be similar, the environment on an evaporitic playa surface is quite different. The geological implications for this newly observed pisolith environment may be considerable. INTRODUCTION 23 &;; E? Carbonate pisoliths are common in the geological record and they can form by a variety of processes in a range of environments. Scholle & Kinsman (1974) list the four o major settings, caliche, caves, hypersaline lagoons and normal marine, and summarize the relevant literature. Processes range from purely inorganic precipitation, as in cave pearls, to the algal oncolites from modern marine and non-marine settings (see for instance Bathurst, 1971 ; CAVE PEARLS AND CONCRETIONS Perhaps the most intensively studied Holocene pisoliths are those forming in caves. The literature on cave pearls is extensive, with some of the more notable contributions made b

Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100)

Droplet size spectra measurements are crucial to obtain a quantitative microphysical description of clouds and fog. However, cloud droplet size measurements are subject to various uncertainties. This work focuses on the error analysis of two key measurement uncertainties arising during cloud droplet size measurements with a conventional droplet size spectrometer (FM-100): first, we addressed the precision with which droplets can be sized with the FM-100 on the basis of the Mie theory. We deduced error assumptions and proposed a new method on how to correct measured size distributions for these errors by redistributing the measured droplet size distribution using a stochastic approach. Second, based on a literature study, we summarized corrections for particle losses during sampling with the FM-100. We applied both corrections to cloud droplet size spectra measured at the high alpine site Jungfraujoch for a temperature range from 0 °C to 11 °C. We showed that Mie scattering led to spikes in the droplet size distributions using the default sizing procedure, while the new stochastic approach reproduced the ambient size distribution adequately. A detailed analysis of the FM-100 sampling efficiency revealed that particle losses were typically below 10% for droplet diameters up to 10 μm. For larger droplets, particle losses can increase up to 90% for the largest droplets of 50 μm at ambient wind speeds below 4.4 m s<sup>−1</sup> and even to >90% for larger angles between the instrument orientation and the wind vector (sampling angle) at higher wind speeds. Comparisons of the FM-100 to other reference instruments revealed that the total liquid water content (LWC) measured by the FM-100 was more sensitive to particle losses than to re-sizing based on Mie scattering, while the total number concentration was only marginally influenced by particle losses. Consequently, for further LWC measurements with the FM-100 we strongly recommend to consider (1) the error arising due to Mie scattering, and (2) the particle losses, especially for larger droplets depending on the set-up and wind conditions

Delta-Reliability

This paper presents a new, non-binary measure of the reliability of broadcast algorithms, called Delta-Reliability. This measure quantifies the reliability of practical broadcast algorithms that, on the one hand, were devised with some form of reliability in mind, but, on the other hand, are not considered reliable according to the ``traditional'' notion of broadcast reliability [HT94]. Our specification of Delta-Reliability suggests a further step towards bridging the gap between theory and practice in the reliability of broadcast algorithms. We illustrate the use of Delta-Reliability through two case studies, namely Bimodal Multicast and IP Multicast

Hybrid Dissemination: Adding Determinism to Probabilistic Multicasting in Large-Scale P2P Systems

Abstract. Epidemic protocols have demonstrated remarkable scalability and robustness in disseminating information on internet-scale, dynamic P2P systems. However, popular instances of such protocols suffer from a number of significant drawbacks, such as increased message overhead in push-based systems, or low dissemination speed in pull-based ones. In this paper we study push-based epidemic dissemination algorithms, in terms of hit ratio, communication overhead, dissemination speed, and resilience to failures and node churn. We devise a hybrid push-based dissemination algorithm, combining probabilistic with deterministic properties, which limits message overhead to an order of magnitude lower than that of the purely probabilistic dissemination model, while retaining strong probabilistic guarantees for complete dissemination of messages. Our extensive experimentation shows that our proposed algorithm outperforms that model both in static and dynamic network scenarios, as well as in the face of large-scale catastrophic failures. Moreover, the proposed algorithm distributes the dissemination load uniformly on all participating nodes. Keywords: Epidemic/Gossip protocols, Information Dissemination, Peer-to-Peer

Nitrous oxide net exchange in a beech dominated mixed forest in Switzerland measured with a quantum cascade laser spectrometer

International audienceNitrous oxide fluxes were measured at the Lägeren CarboEurope IP flux site over the multi-species mixed forest dominated by European beech and Norway spruce. Measurements were carried out during a four-week period in October?November 2005 during leaf senescence. Fluxes were measured with a standard ultrasonic anemometer in combination with a quantum cascade laser absorption spectrometer that measured N2O, CO2, and H2O mixing ratios simultaneously at 5 Hz time resolution. To distinguish insignificant fluxes from significant ones it is proposed to use a new approach based on the significance of the correlation coefficient between vertical wind speed and mixing ratio fluctuations. This procedure eliminated roughly 56% of our half-hourly fluxes. Based on the remaining, quality checked N2O fluxes we quantified the mean efflux at 0.8 ± 0.4 ?mol m?2 h?1 (mean ± standard error). Most of the contribution to the N2O flux occurred during a 6.5-h period starting 4.5 h before each precipitation event. No relation with precipitation amount could be found. Visibility data representing fog density and duration at the site indicate that wetting of the canopy may have as strong an effect on N2O effluxes as does below-ground microbial activity. It is speculated that above-ground N2O production from the senescing leaves at high moisture (fog, drizzle, onset of precipitation event) may be responsible for part of the measured flux. In comparison with the annual CO2 budget of ?342 g C m?2 yr?1 it is estimated that concurrent N2O fluxes offset at least 5% of the greenhouse forcing reduction via net CO2 uptake