3,199 research outputs found
Single microwave photon detection in the micromaser
High efficiency single photon detection is an interesting problem for many
areas of physics, including low temperature measurement, quantum information
science and particle physics. For optical photons, there are many examples of
devices capable of detecting single photons with high efficiency. However
reliable single photon detection of microwaves is very difficult, principally
due to their low energy. In this paper we present the theory of a cascade
amplifier operating in the microwave regime that has an optimal quantum
efficiency of 93%. The device uses a microwave photon to trigger the stimulated
emission of a sequence of atoms where the energy transition is readily
detectable. A detailed description of the detector's operation and some
discussion of the potential limitations of the detector are presented.Comment: 8 pages, 5 figure
LabView Interface for School-Network DAQ Card
A low-cost DAQ card has been developed for school-network cosmic ray detector
projects, providing digitized data from photomultiplier tubes via a standard
serial interface. To facilitate analysis of these data and to provide students
with a starting point for custom readout systems, a model interface has been
developed using the National Instruments LabVIEW(R) system. This user-friendly
interface allows one to initialize the trigger coincidence conditions for
data-taking runs and to monitor incoming or pre-recorded data sets with
updating singles- and coincidence-rate plots and other user-selectable
histograms.Comment: 4 pages, 6 figures. Presented as Paper NS26-119 at IEEE-NSS 2003,
Portland, OR, by R. J. Wilke
Integration or collision? : middle managers\u27 concerns for work-life balance
As increased work demands and longer working hours become the reality for many employees, the concept of work-life balance has received increasing attention. This paper presents findings from an exploratory study of Australian middle managers, which investigated the impact of middle managers’ daily organisational experiences on their lives both in and beyond the workplace. We focus on respondents’ concerns for the encroachment of work on their personal lives, both through the advent of new technologies and the introduction of flexibility initiatives in the workplace. The unwelcome effects of frustration, stress and fatigue highlight the need for organisations to gain a better understanding of employees’ experiences related to work-life balance.<br /
Highly enriched Betaproteobacteria growing anaerobically with p-xylene and nitrate
The identity of the microorganisms capable of anaerobic p-xylene degradation under denitrifying conditions is hitherto unknown. Here, we report highly enriched cultures of freshwater denitrifying bacteria that grow anaerobically with p-xylene as the sole organic carbon source and electron donor. Long curved rods, with 95% 16S rRNA gene sequence identity to Denitratisoma oestradiolicum, dominated the enrichment cultures (>91% of all cells), as detected by phylotype-specific probes. These Rhodocyclaceae microorganisms were distantly related to other denitrifying hydrocarbon-degrading Betaproteobacteria from the Azoarcus-Thauera clade. Complete oxidation p-xylene to CO(2) coupled to denitrification was suggested by quantitative measurements of substrate consumption. Metabolite analysis identified (4-methylbenzyl)succinate and (4-methylphenyl)itaconate, suggesting addition to fumarate as an initial activation reaction
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