Atom gratings produced by large angle atom beam splitters

An asymptotic theory of atom scattering by large amplitude periodic potentials is developed in the Raman-Nath approximation. The atom grating profile arising after scattering is evaluated in the Fresnel zone for triangular, sinusoidal, magneto-optical, and bichromatic field potentials. It is shown that, owing to the scattering in these potentials, two \QTR{em}{groups} of momentum states are produced rather than two distinct momentum components. The corresponding spatial density profile is calculated and found to differ significantly from a pure sinusoid.Comment: 16 pages, 7 figure

Quantitative lameness assessment in the horse based on upper body movement symmetry: The effect of different filtering techniques on the quantification of motion symmetry

Quantitative gait analysis in horses is rapidly gaining importance, both clinically and in research. The number of available systems is increasing, but the methods of signal analysis differ between systems and research groups. Our objectives are to describe and evaluate the effects of different methods of signal analysis for processing of data from equine kinematic gait analysis. To this end, we use theoretical signals based on previously published work, followed by the evaluation of the performance of each technique using real data from horses with induced lameness. Two infinite impulse response (IIR), high-pass filters (Butterworth and Chebyshev), a signal decomposition method and a moving average filtering technique were evaluated. First, we describe methods to fine-tune each filter to the optimal settings based on residual analysis. Second the performance of each filter is evaluated based on differences in calculated symmetry parameters from horses with induced lameness. We show that optimisation of filtering techniques is crucial when processing signals used for objective lameness quantification. Improper selection of the cut-off frequency for IIR filters can result in false negative results (average values above or below predefined reference values). The IIR Butterworth filter and the signal decomposition method achieved the best reduction of unwanted signal components. Knowledge of the available filtering techniques is a pre-requisite for adequate signal processing of gait data from quantitative analysis systems in horses

Values of endoscopic ultrasonography for diagnosis and treatment of duodenal protruding lesions*

Objective: The diagnoses of patients with duodenal protruding lesions are difficult when using conventional examinations such as computed tomography (CT) and conventional endoscope etc. Thus, we investigated the clinical value of endoscopic ultrasonography (EUS) with miniature ultrasonic probes on the diagnosis and treatment of duodenal protruding lesions. Methods: Patients with duodenal protruding lesions who were indicated for EUS were examined by EUS with 12~15 MHz miniature ultrasonic probes and double-cavity electronic endoscope. According to diagnosis of EUS, those patients were indicated for biopsy and treatment received biopsy, endoscopic resection or surgical excision. The postoperative histological results were compared with the preoperative diagnosis of EUS. Those patients without endoscopic resection or surgical excision were periodically followed up with EUS. Results: A total of 169 patients with duodenal protruding lesions were examined by EUS, of which 40 were diagnosed with cysts, 36 with inflammatory protruding or polyp, 25 with Brunner’s gland adenoma, 19 with ectopic pancreas, 17 with gastrointestinal stromal tumor, 12 with extrinsic compression, 12 with minor papilla, 6 with lipoma, 1 with adenocarcinoma and 1 with lymphoma. After EUS examinations, 75 patients received biopsy, endoscopic resection or surgical excision respectively. The postoperative histological results of 70 patients were completely consistent with the preoperative diagnosis of EUS, with 93.33% diagnostic accuracy. The results of follow-up with EUS indicated that duodenal cyst, Brunner’s gland adenoma, ectopic pancreas, gastrointestinal stromal tumor and lipoma remained unchanged within 1~3 years. No related complications occurred among all patients that received EUS examinations. Conclusion: EUS is an effective and reliable diagnostic method for duodenal protruding lesions