4,233 research outputs found

    Study of a signal processor employing a synthetic phase isolator

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    Evaluation of signal data processor employing synthetic phase isolator techniqu

    Dynamical behavior of interacting dark energy in loop quantum cosmology

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    The dynamical behaviors of interacting dark energy in loop quantum cosmology are discussed in this paper. Based on defining three dimensionless variables, we simplify the equations of the fixed points. The fixed points for interacting dark energy can be determined by the Friedmann equation coupled with the dynamical equations {in Einstein cosmology}. But in loop quantum cosmology, besides the Friedmann equation, the conversation equation also give a constrain on the fixed points. The difference of stability properties for the fixed points in loop quantum cosmology and the ones in Einstein cosmology also have been discussed.Comment: 7 pages, 5 figure

    Prevalence of working smoke alarms in local authority inner city housing: randomised controlled trial

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    Objectives To identify which type of smoke alarm is most likely to remain working in local authority inner city housing, and to identify an alarm tolerated in households with smokers. Design Randomised controlled trial. Setting Two local authority housing estates in inner London. Participants 2145 households. Intervention Installation of one of five types of smoke alarm (ionisation sensor with a zinc battery; ionisation sensor with a zinc battery and pause button; ionisation sensor with a lithium battery and pause button; optical sensor with a lithium battery; or optical sensor with a zinc battery). Main outcome measure Percentage of homes with any working alarm and percentage in which the alarm installed for this study was working after 15 months. Results 54.4% (1166/2145) of all households and 45.9% (465/1012) of households occupied by smokers had a working smoke alarm. Ionisation sensor, lithium battery, and there being a smoker in the household were independently associated with whether an alarm was working (adjusted odds ratios 2.24 (95% confidence interval 1.75 to 2.87), 2.20 (1.77 to 2.75), and 0.62 (0.52 to 0.74)). The most common reasons for non-function were missing battery (19%), missing alarm (17%), and battery disconnected (4%). Conclusions Nearly half of the alarms installed were not working when tested 15 months later. Type of alarm and power source are important determinants of whether a household had a working alarm

    DC Electric Fields and Associated Plasma Drifts Observed with the C/NOFS Satellite

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    Initial DC electric field observations and associated plasma drifts are presented from the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite. We present statistical averages of the vector fields for the first year of operations that include both the zonal and radial components of the resulting E x B plasma flows at low latitudes. Magnetic field data from the VEFI science magnetometer are used to compute the plasma flows. The DC electric field detector reveals zonal and radial electric fields that undergo strong diurnal variations, typically displaying eastward and outward-directed fields during the day and westward and downward-directed fields at night. There is considerable variation in the large scale DC electric field data, in both the daytime and nighttime cases, with enhanced structures typically observed at night. In general, the measured zonal DC electric field amplitudes include excursions that extend within the 0.4 - 2 m V/m range, corresponding to E x B drifts of the order of 30-150 m/s. The average vertical or radial electric fields may exceed the zonal fields in amplitude by a factor of 1.5 to 2. Although the data compare well, in a general sense, with previous satellite observations and statistical patterns of vertical ion drifts, the E x B drifts we report from C/NOFS rarely show a pronounced pre-reversal enhancement after sunset. We attribute this to a combination of extreme solar minimum conditions and the fact that the C/NOFS orbit of 401 by 867 km carries the probes essentially above the lower altitude regions where the wind-driven dynamo might be expected to create enhanced upwards drifts in the early evening. Evidence for wavenumber 4 tidal effects and other longitudinal signatures have been detected and will be presented. We also discuss off-equatorial electric fields and their relation to the ambient plasma density

    DC and Structured Electric Fields Observed on the C/NOFS Satellite and Their Association with Longitude, Plasma Density, and Solar Activity

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    Observations of DC electric fields and associated E x B plasma drifts gathered by the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite are presented. We show statistical averages of the vector fields and resulting E x B plasma flows for the first three years of operations as a function of season, longitude, local time, and Fl 0.7 conditions. Magnetic field data from the VEFI science magnetometer are used to compute the plasma flows. Although typically displaying eastward and outward-directed fields during the day and westward and downward-directed fields at night, the data from DC electric field detector often reveal variations from this pattern that depend on longitude, solar activity, and plasma density. Clear "wave-4" tidal effects in both electric field components have been detected and will be presented. Zonal plasma drifts show a marked variation with solar activity and may be used as a proxy for neutral winds at night. Evidence for pre-reversal enhancements in the meridional drifts that depend on solar activity is present for some longitudes, and are corroborated by clear evidence in the plasma density data that the spacecraft journeyed below the F-peak during evenings when the rise in the ionosphere is most pronounced. In addition to DC electric fields, the data reveal considerable electric field structures at large scales (approx 100's of km) that are usually confined to the nightside. Although such electric field structures are typically associated with plasma density depletions and structures, what is surprising is the number of cases in which large amplitude, structured DC electric fields are observed without a significant plasma density counterpart structure, including their appearance at times when the ambient plasma density appears relatively quiescent. We investigate the mapping of structured electric fields along magnetic field lines from distant locations and consider tropospheric thunderstorm sources to explain some of the observations. The dependence of the structuring on season and solar activity will be reported and discussed

    CloudPad - a cloud-based documentation and archiving tool for mixed reality artworks

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    publication-status: AcceptedThis paper reflects on the process of designing and building a documentation and archiving tool named CloudPad on the basis of its first evaluation at Stanford Libraries and the San Francisco Art Institute in September 2010. The paper explores the value of CloudPad and its ability to document individual users’ replay of an artwork within the context of performance documentation and new media archiving, speculating on its possible use within a number of curatorial, educational and creative contexts that are relevant to digital humanities

    Biological and physical observations on a phosphorescent bay in Falmouth Harbor, Jamaica, W. I.

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    A general description of a phosphorescent bay on the northern shore of Jamaica, West Indies, is presented. The brilliant bioluminescence in this embayment is due to the large armored dinoflagellate, Pyrodinium bahamense. It was found in cell densities as high as 200,000 cells/liter. Using a submersible spectrometer, the bioluminescent emission spectrum of these organisms was found to peak at 476 mµ...

    Electric Field and Plasma Density Observations of Irregularities and Plasma Instabilities in the Low Latitude Ionosphere Gathered by the C/NOFS Satellite

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    The Vector Electric Field Investigation (VEFI) on the C/NOFS equatorial satellite provides a unique data set which includes detailed measurements of irregularities associated with the equatorial ionosphere and in particular with spread-F depletions. We present vector AC electric field observations gathered on C/NOFS that address a variety of key questions regarding how plasma irregularities, from meter to kilometer scales, are created and evolve. The talk focuses on occasions where the ionosphere F-peak has been elevated above the C/NOFS satellite perigee of 400 km as solar activity has increased. In particular, during the equinox periods of 2011, the satellite consistently journeyed below the F-peak whenever the orbit was in the region of the South Atlantic anomaly after sunset. During these passes, data from the electric field and plasma density probes on the satellite have revealed two types of instabilities which had not previously been observed in the C/NOFS data set: The first is evidence for 400-500km-scale bottomside "undulations" that appear in the density and electric field data. In one case, these large scale waves are associated with a strong shear in the zonal E x B flow, as evidenced by variations in the meridional (outward) electric fields observed above and below the F-peak. These undulations are devoid of smaller scale structures in the early evening, yet appear at later local times along the same orbit associated with fully-developed spread-F with smaller scale structures. This suggests that they may be precursor waves for spread-F, driven by a collisional shear instability, following ideas advanced previously by researchers using data from the Jicamarca radar. A second result is the appearance of km-scale irregularities that are a common feature in the electric field and plasma density data that also appear when the satellite is near or below the F-peak at night. The vector electric field instrument on C/NOFS clearly shows that the electric field component of these waves is strongest in the zonal direction. These waves are strongly correlated with simultaneous observations of plasma density oscillations and appear both with, and without, evidence of larger-scale spread-F depletions. These km-scale, quasi-coherent waves strongly resemble the bottomside, sinusoidal irregularities reported in the Atmosphere Explorer satellite data set by Valladares et al. and are believed to cause scintillations of VHF radiowaves. We interpret these new observations in terms of fundamental plasma instabilities associated with the unstable, nighttime equatorial ionosphere

    A qualitative study into the use of formal services for dementia by carers from culturally and linguistically diverse (CALD) communities.

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    BACKGROUND: People with dementia and their family carers need to be able to access formal services in the community to help maintain their wellbeing and independence. While knowing about and navigating one's way through service systems is difficult for most people, it is particularly difficult for people from culturally and linguistically diverse (CALD) communities. This study addresses a lack of literature on the use of formal services for dementia by people from CALD backgrounds by examining the experiences and perceptions of dementia caregiving within four CALD communities - Italian, Chinese, Spanish and Arabic-speaking - in south western Sydney, Australia. METHODS: The study used a qualitative design and the methods included focus groups with family carers and one-to-one interviews with bilingual/bicultural community workers, bilingual general practitioners and geriatricians. A total of 121 family carers participated in 15 focus groups and interviews were held with 60 health professionals. All fieldwork was audiotaped, transcribed and subjected to thematic analysis. RESULTS: People from CALD communities are often unfamiliar with the concept of formal services and there may be strong cultural norms about maintaining care within the family, rather than relying on external services. CALD communities often have limited knowledge of services. There is a preference for services that will allow families to keep their relative at home, for safety as well as cultural reasons, and they are particularly reluctant to use residential care. While there is a preference for ethno-specific or multicultural services, mainstream services also need to ensure they are more flexible in providing culturally appropriate care. Positive outcomes occur when ethno-specific services work in partnership with mainstream programs. Dementia service providers need to develop a trusting relationship with their local CALD communities and promote their services in a way that is understandable and culturally acceptable to members of these communities. CONCLUSIONS: While members of CALD communities may have difficulties accessing formal services, they will use them if they are culturally and linguistically appropriate and can meet their needs. There are a number of ways to improve service provision to CALD communities and the responsibility for this needs to be shared by a range of stakeholders

    Impact of soil conditions on hydrology and water quality for a brown clay in the north-eastern cereal zone of Australia

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    Hydrology and water quality impacts of alternative land management practices are poorly quantified for semi-arid environments in the northern Australia cropping zone, yet wide-scale changes in tillage practices and land use were being recommended based on experience from other environments. The objective of this study was to explore changes in soil profile and catchment hydrology and water quality associated with different soil surface conditions created by different tillage and grazing practices. Soil water, runoff, and suspended sediment concentrations were monitored on 4 contour bay catchments over an 18-year period. Soil conditions were described by soil moisture, soil cover, and surface roughness in order to explore functional relationships between management, hydrology, and water quality. The site was chosen to represent the drier margins of cropping in southern Queensland where clay soils with high water-holding capacity, in conjunction with fallowing to store water for later crop growth, are an essential risk management tool. Accumulation of soil water in fallows was inefficient, with fallow efficiencies ranging from 7 to 40% due to high evaporation and runoff losses. Runoff amount was determined by soil water content, which was strongly influenced by antecedent rainfall, water use, and evaporation patterns. Surface cover and roughness had subtle influences on runoff, and a greater effect on suspended sediment concentration. Runoff and suspended sediment losses were considerably lower under pasture than cropping. A participative approach between farmers and scientists was demonstrated to be an efficient method to carry out an extensive and long-term catchment study at a remote location. This study provides benchmark data for future hydrologic and water quality investigations. © CSIRO 2009
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