Fully Overheated Single-Electron Transistor

We consider the fully overheated single-electron transistor, where the heat balance is determined entirely by electron transfers. We find three distinct transport regimes corresponding to cotunneling, single-electron tunneling, and a competition between the two. We find an anomalous sensitivity to temperature fluctuations at the crossover between the two latter regimes that manifests in an exceptionally large Fano factor of current noise.Comment: 6 pages, 3 figures, includes Appendi

Theory of temperature fluctuation statistics in superconductor-normal metal tunnel structures

We describe the statistics of temperature fluctuations in a SINIS structure, where a normal metal island (N) is coupled by tunnel junctions (I) to two superconducting leads (S). We specify conditions under which this structure exhibits manifestly non-Gaussian fluctuations of temperature. We consider both the Gaussian and non-Gaussian regimes of these fluctuations, and the current fluctuations that are caused by the fluctuating temperature. We also describe a measurement setup that could be used to observe the temperature fluctuations.Comment: 10 pages, 9 figures, final versio

Functional renormalization group study of the Anderson--Holstein model

We present a comprehensive study of the spectral and transport properties in the Anderson--Holstein model both in and out of equilibrium using the functional renormalization group (FRG). We show how the previously established machinery of Matsubara and Keldysh FRG can be extended to include the local phonon mode. Based on the analysis of spectral properties in equilibrium we identify different regimes depending on the strength of the electron--phonon interaction and the frequency of the phonon mode. We supplement these considerations with analytical results from the Kondo model. We also calculate the non-linear differential conductance through the Anderson--Holstein quantum dot and find clear signatures of the presence of the phonon mode.Comment: 19 pages, 8 figure

Two Burial Traditions of the Crusade Period on the Karelian Isthmus and in Ladoga Karelia

The Ladoga Archaeological Expedition of the Peter the Great Museum of Anthropology and Ethnography (Kunstkamera; MAE) RAS, St Petersburg, jointly with the University of Turku (Finland), has recently excavated several funerary sites on the Karelian Isthmus and in the Ladoga Karelia region. The materials yielded by these investigations enable the reconsideration of information from previous excavations. Among the recent exceptional finds are the burials on the slopes of the Sänkinmäki and Pihlajamäki hills in the northern extremity of the island of Kilpolansaari. The material from these sites, as well as radiocarbon dating, demonstrates that in the 13th century, a part of the medieval Karelian population, at least in the Ladoga Karelia region, continued to practise archaic rites that includedcremations on the ground surface

Giant current fluctuations in an overheated single electron transistor

Interplay of cotunneling and single-electron tunneling in a thermally isolated single-electron transistor (SET) leads to peculiar overheating effects. In particular, there is an interesting crossover interval where the competition between cotunneling and single-electron tunneling changes to the dominance of the latter. In this interval, the current exhibits anomalous sensitivity to the effective electron temperature of the transistor island and its fluctuations. We present a detailed study of the current and temperature fluctuations at this interesting point. The methods implemented allow for a complete characterization of the distribution of the fluctuating quantities, well beyond the Gaussian approximation. We reveal and explore the parameter range where, for sufficiently small transistor islands, the current fluctuations become gigantic. In this regime, the optimal value of the current, its expectation value, and its standard deviation differ from each other by parametrically large factors. This situation is unique for transport in nanostructures and for electron transport in general. The origin of this spectacular effect is the exponential sensitivity of the current to the fluctuating effective temperature.Comment: 10 pages, 11 figure

Scavenging of ultrafine particles by rainfall at a boreal site: observations and model estimations

International audienceValues of the scavenging coefficient were determined from observations of ultrafine particles (with diameters in the range 10?510 nm) during rain events at a boreal forest site in Southern Finland between 1996 and 2001. The estimated range of values of the scavenging coefficient was [7×10?6?4×10?5] s?1, which is generally higher than model calculations based only on below-cloud processes (Brownian diffusion, interception, and typical charge effects). A new model that includes below-cloud scavenging processes, mixing of ultrafine particles from the boundary layer (BL) into cloud, followed by cloud condensation nuclei activation and in-cloud removal by rainfall, is presented. The effective scavenging coefficients estimated from this new model have values comparable with those obtained from observations. Results show that ultrafine particle removal by rain depends on aerosol size, rainfall intensity, mixing processes between BL and cloud elements, in-cloud scavenged fraction, in-cloud collection efficiency, and in-cloud coagulation with cloud droplets. Implications for the treatment of scavenging of BL ultrafine particles in numerical models are discussed

Towards a Protocol for the Collection of VGI Vector Data

A protocol for the collection of vector data in Volunteered Geographic Information (VGI) projects is proposed. VGI is a source of crowdsourced geographic data and information which is comparable, and in some cases better, than equivalent data from National Mapping Agencies (NMAs) and Commercial Surveying Companies (CSC). However, there are many differences in how NMAs and CSC collect, analyse, manage and distribute geographic information to that of VGI projects. NMAs and CSC make use of robust and standardised data collection protocols whilst VGI projects often provide guidelines rather than rigorous data collection specifications. The proposed protocol addresses formalising the collection and creation of vector data in VGI projects in three principal ways: by manual vectorisation; field survey; and reuse of existing data sources. This protocol is intended to be generic rather than being linked to any specific VGI project. We believe that this is the first protocol for VGI vector data collection that has been formally described in the literature. Consequently, this paper shall serve as a starting point for on-going development and refinement of the protocol

Basic characteristics of atmospheric particles, trace gases and meteorology in a relatively clean Southern African Savannah environment

We have analyzed one year (July 2006–July 2007) of measurement data from a relatively clean background site located in dry savannah in South Africa. The annual-median trace gas concentrations were equal to 0.7 ppb for SO<sub>2</sub>, 1.4 ppb for NO<sub>x</sub>, 36 ppb for O<sub>3</sub> and 105 ppb for CO. The corresponding PM<sub>1</sub>, PM<sub>2.5</sub> and PM<sub>10</sub> concentrations were 9.0, 10.5 and 18.8 μg m<sup>−3</sup>, and the annual median total particle number concentration in the size range 10–840 nm was 2340 cm<sup>−3</sup>. During Easterly winds, influence of industrial sources approximately 150 km away from the measurement site was clearly visible, especially in SO<sub>2</sub> and NO<sub>x</sub> concentrations. Of gases, NO<sub>x</sub> and CO had a clear annual, and SO<sub>2</sub>, NO<sub>x</sub> and O<sub>3</sub> clear diurnal cycle. Atmospheric new-particle formation was observed to take place in more than 90% of the analyzed days. The days with no new particle formation were cloudy or rainy days. The formation rate of 10 nm particles varied in the range of 0.1–28 cm<sup>−3</sup> s<sup>−1</sup> (median 1.9 cm<sup>−3</sup> s<sup>−1</sup>) and nucleation mode particle growth rates were in the range 3–21 nm h<sup>−1</sup> (median 8.5 nm h<sup>−1</sup>). Due to high formation and growth rates, observed new particle formation gives a significant contribute to the number of cloud condensation nuclei budget, having a potential to affect the regional climate forcing patterns