Quantum superposition at the half-metre scale.

The quantum superposition principle allows massive particles to be delocalized over distant positions. Though quantum mechanics has proved adept at describing the microscopic world, quantum superposition runs counter to intuitive conceptions of reality and locality when extended to the macroscopic scale, as exemplified by the thought experiment of Schrödinger's cat. Matter-wave interferometers, which split and recombine wave packets in order to observe interference, provide a way to probe the superposition principle on macroscopic scales and explore the transition to classical physics. In such experiments, large wave-packet separation is impeded by the need for long interaction times and large momentum beam splitters, which cause susceptibility to dephasing and decoherence. Here we use light-pulse atom interferometry to realize quantum interference with wave packets separated by up to 54 centimetres on a timescale of 1 second. These results push quantum superposition into a new macroscopic regime, demonstrating that quantum superposition remains possible at the distances and timescales of everyday life. The sub-nanokelvin temperatures of the atoms and a compensation of transverse optical forces enable a large separation while maintaining an interference contrast of 28 per cent. In addition to testing the superposition principle in a new regime, large quantum superposition states are vital to exploring gravity with atom interferometers in greater detail. We anticipate that these states could be used to increase sensitivity in tests of the equivalence principle, measure the gravitational Aharonov-Bohm effect, and eventually detect gravitational waves and phase shifts associated with general relativity.

Precision angle sensor using an optical lever inside a Sagnac interferometer.

We built an ultra-low-noise angle sensor by combining a folded optical lever and a Sagnac interferometer. The instrument has a measured noise floor of 1.3 prad/√Hz at 2.4 kHz. We achieve this record angle sensitivity using a proof-of-concept apparatus with a conservative N=11 bounces in the optical lever. This technique could be extended to reach subpicoradian/√Hz sensitivities with an optimized design.

Broadband optical serrodyne frequency shifting.

We demonstrate serrodyne frequency shifting of light from 200 MHz to 1.2 GHz with an efficiency of better than 60%. The frequency shift is imparted by an electro-optic phase modulator driven by a high-frequency high-fidelity sawtooth waveform that is passively generated by a commercially available nonlinear transmission line. We also implement a push-pull configuration using two serrodyne-driven phase modulators, allowing for continuous tuning between -1.6 GHz and +1.6 GHz. Compared with competing technologies, this technique is simple and robust, and it offers the largest available tuning range in this frequency band.

Identification of vertical growth phase in malignant melanoma. A study of interobserver agreement.

Ninety-four H & E-stained slides of malignant melanoma were circulated to 6 pathologists in 2 university departments. For each slide, the growth phase of the lesion, Breslow thickness, and Clark level were determined by each observer. The aims of the study were to evaluate agreement between nonspecialist pathologists in identifying the vertical growth phase in malignant melanoma and to compare agreement for the growth phase with agreement for Breslow thickness and the Clark level. Our results show that although overall agreement for the growth phase is moderate, agreement between experienced observers is good. In fact agreement for the growth phase among this group was equal to the agreement for Breslow thickness. Overall agreement for Breslow thickness also was good but for the Clark level was only fair. These findings suggest that if the predictive value of the vertical growth phase proves to be robust, it will be used with an acceptable level of accuracy in routine diagnostic practice.

Adenoacanthoma of the endometrium: morphological changes induced by human papillomavirus.

The observation of koilocyte-like features in the squamous epithelium of some endometrial adenoacanthomas prompted an investigation into a possible viral aetiology. These changes closely resemble those that occur in the ectocervical mucosa which are accepted as morphological evidence of human papillomavirus (HPV) infection. Sections of 87 hysterectomy specimens removed for endometrial carcinoma over 12 years, together with preoperative curettings, were reviewed for the presence of acanthomatous change and for appearances suggestive of HPV infection. The ages of the women ranged from 36 to 84 years, average age 62.6. Light microscopical examination showed koilocytosis, papillary formations, and intranuclear eosinophilic inclusions of both squamous and glandular epithelium in some tumours. Immunocytochemistry and DNA in situ hybridisation indicated the presence of HPV antigen in squamous and glandular cells, and perinuclear virus particles characteristic of HPV were seen on electron microscopical examination in those cells with nuclear inclusions. HPV probably infects endometrial adenocarcinomas directly from the cervix but it is unlikely that it has an aetiological role. It is possible, however, that in addition to being a "passenger," the virus may stimulate squamous metaplasia in some adenocarcinomas of the endometrium and may also exert some influence on their behaviour.

Continuous hepatic artery infusion with an implantable pump: problems with hepatic artery anomalies.

The implantable pump for continuous hepatic artery chemotherapy requires even distribution of the chemotherapy to the whole liver for maximum efficacy. The hepatic arterial supply and its anomalies must be understood to achieve this. We reviewed the arteriograms of 100 patients who were potentially arterial perfusion candidates. Fifty percent had normal hepatic arterial anatomy. Twenty percent had a replaced or accessory right hepatic artery and 17% had an accessory or replaced left hepatic artery. The methods used to implant the pump catheters in these anomalous situations were reviewed. The use of dual catheter pumps for arterial anomalies has necessitated extended operative time and increased the risk of uneven hepatic perfusion. Catheterization of the portal vein, which is technically simpler, deserves consideration as an alternative in the presence of an aberrant arterial system.

The relationship of sun exposure and solar elastosis to skin cancer in a high risk population.

The significance of chronic sun exposure in the pathogenesis of skin cancers squamous cell carcinoma (SCC). basal cell carcinoma (BCC) and melanoma was morphologically assessed. Histological sections of 223 consecutive skin cancers were reviewed, these were stained with aldehyde fuchsin and the degree of associated solar elastosis estimated. The anatomic distribution of SCC and BCC and the SCC:BCC ratio were significantly different in the Irish population studied when compared to other major series. It was found that a significant proportion of SCCs and BCCs were not related to chronic sun exposure. As expected, only melanomas arising in lentigo maligna were associated with long-term irradiation. It is proposed that other environmental agents and genetic factors may also contribute to the high incidence of skin cancer in Ireland.

Primary hyperoxaluria--a case report.

A case of primary hyperoxaluria which presented with progressive renal failure in a 34 year old woman is reported. The patient died six years following the initial diagnosis and post mortem examination revealed widespread deposition of oxalate crystals in her tissues.

Percutaneous fine needle aspiration of pulmonary mass lesions--a critical examination of the accuracy of cell typing of malignant tumours.

All the biopsies of pulmonary mass lesions obtained by percutaneous needle aspiration over a seven year period were reviewed. Emphasis is laid upon the differences in cell typing of malignant tumours when two types of preparation of the same tissue, cytological smears and tissue sections are examined. Some problems in cell typing are discussed and suggestions for improved proficiency are made.

Recruitment learning of boolean functions in sparse random networks.

This work presents a new class of neural network models constrained by biological levels of sparsity and weight-precision, and employing only local weight updates. Concept learning is accomplished through the rapid recruitment of existing network knowledge - complex knowledge being realised as a combination of existing basis concepts. Prior network knowledge is here obtained through the random generation of feedforward networks, with the resulting concept library tailored through distributional bias to suit a particular target class. Learning is exclusively local - through supervised Hebbian and Winnow updates - avoiding the necessity for backpropagation of error and allowing remarkably rapid learning. The approach is demonstrated upon concepts of varying difficulty, culminating in the well-known Monks and LED benchmark problems.

Improved prediction of bacterial transcription start sites.

MOTIVATION: Identifying bacterial promoters is an important step towards understanding gene regulation. In this paper, we address the problem of predicting the location of promoters and their transcription start sites (TSSs) in Escherichia coli. The accepted method for this problem is to use position weight matrices (PWMs), which define conserved motifs at the sigma-factor binding site. However this method is known to result in large numbers of false positive predictions. RESULTS: Our approaches to TSS prediction are based upon an ensemble of support vector machines (SVMs) employing a variant of the mismatch string kernel. This classifier is subsequently combined with a PWM and a model based on distribution of distances from TSS to gene start. We investigate the effect of different scoring techniques and quantify performance using area under a detection-error tradeoff curve. When tested on a biologically realistic task, our method provides performance comparable with or superior to the best reported for this task. False positives are significantly reduced, an improvement of great significance to biologists. AVAILABILITY: The trained ensemble-SVM model with instructions on usage can be downloaded from http://eresearch.fit.qut.edu.au/downloads

Strategic planning: a challenge of medical record professionals.

Strategic planning guides the organization's short and long-term activities. The sharper business focus of today's health care environment forces rapid fire decision-making and shortens the strategy time frame. In this condensed time frame, strategists have little patience for inaccurate or untimely information.

Body temperature regulation in a desert lizard, Sauromalus obesus, under undisturbed field conditions.

1. Mean selected body temperatures (MSBTs), measured by radiotelemetry, are presented for 15 chuckwallas on 26 animal days. 2. MSBT, during the period of activity, ranged from 37.3 to 39.8 degrees C (means = 38.8 +/- 0.2 SE degrees C) while MSBTs, from the time lizards attained their first high set point to the time that solar radiation ceased, ranged from 36.1 to 39.6 degrees C (means = 38.3 +/- 0.2 SE degrees C). 3. On cloudy, cool days, animals could not maintain high Tbs because of the absence of solar radiation. 4. On sunny March and April days, animals were active for 5-6 hr but Tb then fell rapidly to low levels. 5. From late April to mid May, animals were active for 7-8 hr and Tbs did not fall as drastically because of higher Tas after sunset. 6. August was the time of year (for this study) when chuckwallas had the highest effective 24 hr Tb but it was also the time when they had the shortest activity interval.

Fever response in laboratory-maintained and free-ranging chuckwallas (Sauromalus obesus).

The fever response was studied in laboratory-maintained and free-ranging chuckwallas. Five animals were used in a self-pairing laboratory experiment in which each animal was first injected with a sterile, pyrogen-free saline solution. Approximately 7 days later, each individual was injected with a solution of 4.75 x 10(9) Aeromonas sobria (formerly A. hydrophila). Saline-injected individuals had a mean preferred body temperature (MPBT) of 36.8 +/- 0.4 (SE) degrees C, whereas bacteria-injected animals had a MPBT of 39.1 +/- 0.6 (SE) degrees C (an increase of 2.3 degrees C). The within-animal variance associated with MPBT was significantly decreased in bacteria-injected animals. In the natural environment, 10 chuckwallas were divided into five pairs, so that both animals of a pair could be monitored simultaneously. One animal in a pair was given an injection of sterile, pyrogen-free saline, whereas the other animal received an injection of 4.75 x 10(9) A. sobria. On day 2, both the MPBT and the rate of heating were greater in bacteria-injected animals. The between-animal variation in fever MPBT was greater than the mean increase in MPBT of fever animals. Also, the absolute level of the MPBT during the fever response was related to time of the year, with spring-active animals having the highest fever MPBTs.