Laboratory plasma probe studies

Diagnostic experiments performed in a collisionless plasma using CO2 as the working gas are described. In particular, simultaneous measurements that have been performed by means of Langmuir- and RF-probes are presented. A resonance occurring above the parallel resonance in the frequency characteristic of a two electrode system is interpreted as being due to the resonant excitation of electroacoustic waves

Quantum detectors for the third cumulant of current fluctuations

We consider the measurement of the third cumulant of current fluctuations arising from a point contact, employing the transitions that they cause in a quantum detector connected to the contact. We detail two generic detectors: a quantum two-level system and a harmonic oscillator. In these systems, for an arbitrary relation between the voltage driving the point contact and the energy scales of the detectors, the results can be expressed in terms of an effective detector temperature T_eff. The third cumulant can be found from the dependence of T_eff on the sign of the driving voltage. We find that proper ordering of the fluctuation operators is relevant in the analysis of the transition rates. This is reflected in the effective Fano factor for the third cumulant measured in such setups: it depends on the ratio of the voltage and an energy scale describing the circuit where the fluctuations are produced.Comment: 12+ pages, 8 figure

Slow Vibrations in Transport through Molecules

We show how one can measure the signal from slow jumps of a single molecule between metastable positions using a setup where the molecule is fixed to one lead, and one of the coupling strengths is controlled externally. Such a measurement yields information about slow processes deforming the molecule in times much longer than the characteristic time scales for the electron transport process.Comment: 4 pages, 3 figure

Agricultural Production with Change and Uncertainty: A Temporal Case Study Simulation of Colorado Potato Beetle

Changes in climatic and policy environments combined with uncertainty related to stochastic environmental fluctuations make design of invasive pest policy challenging. These external changes are often exacerbated by changes in the species characteristics. We discuss facing local change and uncertainty when deciding ex ante on a specific policy strategy. Our empirical case deals with an invasive agricultural pest, Colorado potato beetle, and agricultural production in Finland. Invasions are modelled as temporally random events and stochasticity in key variables is built into the analysis. The viability of two specific policy options is evaluated given uncertainty and local change.Colorado potato beetle, protected zone, zone protegee, invasive alien species, Crop Production/Industries, Q1, Q28, Q58,

Improved metrics collection and correlation for the CERN cloud storage test framework

Storage space is one of the most important ingredients that the European Organization for Nuclear Research (CERN) needs for its experiments and operation. Part of the Data & Storage Services (IT-DSS) group’s work at CERN is focused on testing and evaluating the cloud storage system that is provided by the openlab partner Huawei, Huawei Universal Disk Storage System (UDS). As a whole, the system consists of both software and hardware. The objective of the Huawei-CERN partnership is to investigate the performance of the cloud storage system. Among the interesting questions are the system’s scalability, reliability and ability to store and retrieve files. During the tests, possible bugs and malfunctions can be discovered and corrected. Different versions of the storage software that runs inside the storage system can also be compared to each other. The nature of testing and benchmarking a storage system gives rise to several small tasks that can be done during a short summer internship. In order to test the storage system a test framework developed by the DSS group is used. The framework consists of various types of file transfer tests, client and server monitoring programs and log file analysis programs. Part of the work done was additions to the existing framework and part was developing new tools. Metrics collection was the central theme. Metrics are to be understood as system statistics, such as memory consumption or processor usage. Memory usage and disk reads/writes were added to the existing client real-time monitoring framework. CPU and memory usage, network traffic (bytes received/sent) and the number of processes running are collected from a client computer before and after a daily test. Two other additions are visualization for storage system log files, as well as a new monitoring tool for the storage system. This report is divided into parts describing each part of the framework that was improved or added, the problem and the final solution. A short description of the code and the architecture are also included