An electrical equivalent circuit to simulate the output power of an AlGaAs/GaAs planar Gunn diode

The planar Gunn diode offers the potential of microwave, milli-metric and THz based oscillator which can be fabricated as part of a microwave monolithic integrated circuit (mmic). To-date the RF output power has been too low for many applications. This paper looks at a simple electrical equivalent circuit model representation of an aluminium gallium arsenide (AlGaAs) based planar Gunn diode with an active channel length of approximately 4μm and width of 120μm. The model indicated a maximum RF output power of +5dBm compared with published experimental results of –19dBm for similar diodes

An electrical equivalent circuit to simulate the output power of an AlGaAs/GaAs planar Gunn diode

The planar Gunn diode offers the potential of microwave, milli-metric and THz based oscillator which can be fabricated as part of a microwave monolithic integrated circuit (mmic). To-date the RF output power has been too low for many applications. This paper looks at a simple electrical equivalent circuit model representation of an aluminium gallium arsenide (AlGaAs) based planar Gunn diode with an active channel length of approximately 4μm and width of 120μm. The model indicated a maximum RF output power of +5dBm compared with published experimental results of –19dBm for similar diodes

FIRST SEARCHES FOR OPTICAL COUNTERPARTS TO GRAVITATIONAL-WAVE CANDIDATE EVENTS

During the LIGO and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type

An electrical equivalent circuit to simulate the output power of an AlGaAs/GaAs planar Gunn diode oscillator

The planar Gunn diode offers the potential of microwave, milli‐metric and THz‐based oscillators, which can be fabricated as part of a microwave monolithic integrated circuit (mmic). The paper develops an electrical representation of an aluminum gallium arsenide (AlGaAs) based planar Gunn diode with an active channel length of approximately 4 μm and width of 120 μm, embedded in an oscillator circuit. The work indicates a maximum simulated RF output power of +5 dBm compared with published experimental results of −19 dBm for similar diodes

A sustainable programme to prevent falls and near falls in community dwelling older people: results of a randomised trial

STUDY OBJECTIVE—In the causative mechanism of falls among older community dwellers, slips and trips have been found to be significant precursors. The purpose of the two year trial was to assess the effectiveness of multi-component interventions targeting major risk factors for falls in reducing the incidence of slips, trips and falls among the well, older community.
DESIGN—Four groups with approximately equal numbers of participants were randomly allocated to interventions. The prevention strategies included education and awareness raising of falls risk factors, exercise sessions to improve strength and balance, home safety advice to modify environmental hazards, and medical assessment to optimise health. The interventions combined the strategies in an add on approach. The first intervention group receiving the information session only was regarded as the control. The outcome of interest was the occurrence of a slip, trip or fall, monitored prospectively using a daily calendar diary.
PARTICIPANTS AND SETTING—Two hundred and fifty two members of the National Seniors Association in the Brisbane district agreed to participate. National Seniors clubs provide a forum for active, community dwelling Australians aged 50 and over to participate in policy, personal development and recreation.
MAIN RESULTS—Using Cox's proportional hazards regression model, adjusted hazard ratios comparing intervention groups with the control ranged from 0.35 (95% CI 0.17, 0.73) to 0.48 (0.25, 0.91) for slips; 0.29 (0.16, 0.51) to 0.45 (0.27, 0.74) for trips; and 0.60 (0.36,( )1.01) to 0.82 (0.51, 1.31) for falls. While calendar monitoring recorded outcome, it was also assessed as a prevention strategy by comparing the intervention groups with a hypothetical non-intervened group. At one year after intervention, reductions in the probability of slips, trips and falls (61(95%CI 54, 66)%; 56 (49, 63)%; 29( )(22, 36)% respectively) were demonstrated.
CONCLUSIONS—This study makes an important contribution to the priority community health issue of falls prevention by showing that effective, sustainable, low cost programmes can be introduced through community-based organisations to reduce the incidence of slips, trips and falls in well, older people.


Keywords: falls prevention ; community dwelling; randomised tria