The Free Press in a Democratic Society

I would like to talk instead about the obligational twin—that is the necessity, indeed, in my estimation, the duty, which all government officers have, and particularly in those matters which the military shares with the State Department in responsibility, to find ways of informing the American people about what is being done in their name, in a manner that does inform but does not hamper or cripple the policies

Research into Western Australian honeys

On the 26 February 2002, the then Department of Agriculture released a media statement about the results of research conducted by Rob Manning and Nola Mercer about WA honeys’ antimicrobial activity using an assay developed in New Zealand. The research showed that Western Australian honey had some of the highest activity levels in the world due to a naturally occurring enzyme in the honey. Upon dilution of honey, the enzyme glucose oxidase produces low concentrations of hydrogen peroxide which is the source of its antimicrobial activity. It is different to Manuka (Leptospermum scoparium) honey from New Zealand which is termed a ‘non-peroxide’ (Molan and Russell 1988) honey because it’s activity is derived from a chemical called methylglyoxal. The chemical, the “Unique Manuka Factor (UMF)” in Manuka is unique and so far it has only been discovered in honey from Leptospermum species (Allen et al. 1991; Anon 1998; Davis 2005) which includes a species found in Western Australia (Beeinformed 2008). Since 2002

Honeybee pollination, technical data for potential honey-bee pollinated crops and orchards in Western Australia

The future of pollination of crops by beekeepers in Western Australia is encouraging. The number of crops that can be pollinated are on the increase and in the fruit sector, new varieties are being planted and established crops are being expanded.The use of honeybees in pollination will become very important as cropping areas enlarge and as export markets expand, with premium prices for quality. This bulletin covers general guidance on developing a bee pollination services with specific advice for managing pollination services for vegetable, broadacre grain, fruit, nuts crops.https://researchlibrary.agric.wa.gov.au/bulletins/1232/thumbnail.jp

Beekeeping In Western Australia

This Bulletin provides background information for those wishing to learn to keep bees or learn about beekeeping in Western Australia.https://researchlibrary.agric.wa.gov.au/bulletins/1259/thumbnail.jp

Self-starting optical–electrical–optical homodyne clock recovery for phase-modulated signals

We propose a novel self-homodyne optical–electrical–optical clock recovery technique for binary phase-shift keying (BPSK) signals using commercial optical and electrical components. We present the principle of operation as well as a proof-of-concept experiment for a 10.7 Gb/s BPSK signal clock recovery transmitted over a dispersion-compensated link of 20 km of single-mode fiber. Suppression of pattern-related frequency noise at the output of the recovered clock is shown. The timing jitter of the recovered clock at 10.7 GHz was measured to be ∼450 fs (integration range: 100 Hz–10 MHz)

Novel all-optical on-off-keyed to alternate-mark-inversion converter

We numerically investigate a novel 40 Gbps OOK to AMI all-optical modulation format converter employing an SOA-based Mach-Zehnder interferometer.  We demonstrate operation with a 27-1 PRBS and explain the phase modulation's relationship with patterning

All-optical technique for modulation format conversion from on-off-keying to alternate-mark-inversion

We propose and numerically investigate for the first time a novel all-optical on-off-keying to alternate-mark-inversion modulation format converter operating at 40 Gbps employing a semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI). Wedemonstrate that this SOA-MZI operates as a pulse subtractor, and in the absence of patterning will produce perfectly phase inverted pulses regardless of the individual SOA phase excursions. We use a comprehensive computer model to illustrate the impact of patterning on the output phase modulation which is quantified through the definition of the phase compression factor

Pattern compensation in SOA-based gates

We propose a novel scheme employing complementary data inputs to overcome the patterning normally associated with semiconductor optical amplifier based gates and demonstrate the scheme experimentally at 42.6Gb/s. The scheme not only avoids introducing patterning during switching, but also compensates for much of the patterning present on theinput data. A novel gate was developed for the experiment to provide the complementary signals required for the scheme

High-bandwidth generation of duobinary and alternate-mark-inversion modulation formats using SOA-based signal processing

We report on the novel all-optical generation of duobinary (DB) and alternate-mark-inversion (AMI) modulation formats at 42.6 Gb/s from an input on-off keyed signal. The modulation converter consists of two semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer gates. A detailed SOA model numerically confirms the operational principles and experimental data shows successful AMI and DB conversion at 42.6 Gb/s. We also predict that the operational bandwidth can be extended beyond 40 Gb/s by utilizing a new pattern-effect suppression scheme, and demonstrate dramatic reductions in patterning up to 160 Gb/s. We show an increasing trade-off between pattern-effect reduction and mean output power with increasing bitrate

All-optical modulation converter for on-off keying to duobinary and alternate-mark inversion at 42.6 Gbps

Advanced modulation formats have become increasingly important as telecoms engineers strive for improved tolerance to both linear and nonlinear fibre-based transmission impairments. Two important modulation schemes are Duobinary (DB) and Alternate-mark inversion (AMI) [1] where transmission enhancement results from auxiliary phase modulation. As advanced modulation formats displace Return-to-zero On-Off Keying (RZ-OOK), inter-modulation converters will become increasingly important. If the modulation conversion can be performed at high bitrates with a small number of operations per bit, then all-optical techniques may offer lower energy consumption compared to optical-electronic-optical approaches. In this paper we experimentally demonstrate an all-optical system incorporating a pair of hybrid-integrated semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI) gates which translate RZ-OOK to RZ-DB or RZ-AMI at 42.6 Gbps. This scheme includes a wavelength conversion to arbitrary output wavelength and has potential for high-level photonic integration, scalability to higher bitrates, and should exhibit regenerative properties [2]