PCR detection and analysis of Pasteurella multocida from the tonsils of slaughtered pigs in Vietnam

A total of 36 tonsil swab samples were collected from healthy swine prior to slaughter at the abattoirs in Can tho and Tien giang provinces of Southern Vietnam, The presence of Pasteurella multocida in these samples was detected by the combination of direct cultivation and isolation, mouse inoculation and the polymerase chain reaction (PM-PCR). P. multocida was detected in 16 samples by PCR, with 17 strains ultimately isolated. All samples were negative for serogroup B by HSB-PCR and conventional serotyping, with isolates identified as A:3, D:1 or D:3. In addition, all samples were determined to be negative for the P. multocida toxin (PMT). Characterisation of isolated P, multocida by REP-PCR and biotyping revealed nine distinct REP profiles and seven biotypes among the 17 isolates. Some correlation was seen with P. multocida isolated from a previous Australian outbreak of acute swine pasteurellosis, and those isolated from fowl cholera outbreaks in Vietnamese poultry. (C) 2000 Elsevier Science B.V. All rights reserved.

Multisensorial obstacles detection and classification for ADAS and autonomous driving

A reliable perception of the real world is a key-feature for an autonomous vehicle and the Advanced Driver Assistance Systems (ADAS). Obstacles detection (OD) is one of the main components for the correct reconstruction of the dynamic world. Historical approaches based on stereo vision and other 3D perception technologies (e.g. LIDAR) have been adapted to the ADAS first and autonomous ground vehicles, after, providing excellent results. The obstacles detection is a very broad field and this domain counts a lot of works in the last years. In academic research, it has been clearly established the essential role of these systems to realize active safety systems for accident prevention, reflecting also the innovative systems introduced by industry. These systems need to accurately assess situational criticalities and simultaneously assess awareness of these criticalities by the driver; it requires that the obstacles detection algorithms must be reliable and accurate, providing: a real-time output, a stable and robust representation of the environment and an estimation independent from lighting and weather conditions. Initial systems relied on only one exteroceptive sensor (e.g. radar or laser for ACC and camera for LDW) in addition to proprioceptive sensors such as wheel speed and yaw rate sensors. But, current systems, such as ACC operating at the entire speed range or autonomous braking for collision avoidance, require the use of multiple sensors since individually they can not meet these requirements. It has led the community to move towards the use of a combination of them in order to exploit the benefits of each one. Pedestrians and vehicles detection are ones of the major thrusts in situational criticalities assessment, still remaining an active area of research. ADASs are the most prominent use case of pedestrians and vehicles detection. Vehicles should be equipped with sensing capabilities able to detect and act on objects in dangerous situations, where the driver would not be able to avoid a collision. A full ADAS or autonomous vehicle, with regard to pedestrians and vehicles, would not only include detection but also tracking, orientation, intent analysis, and collision prediction. The system detects obstacles using a probabilistic occupancy grid built from a multi-resolution disparity map. Obstacles classification is based on an AdaBoost SoftCascade trained on Aggregate Channel Features. A final stage of tracking and fusion guarantees stability and robustness to the result.

The detection and identification of extraneous metals in material conveyance systems

The aim of this work was to design and build an equipment which can detect ferrous and non-ferrous objects in conveyed commodities, discriminate between them and locate the object along the belt and on the width of the belt. The magnetic induction mechanism was used as a means of achieving the objectives of this research. In order to choose the appropriate geometry and size of the induction field source, the field distributions of different source geometries and sizes were studied in detail. From these investigations it was found the square loop geometry is the most appropriate as a field generating source for the purpose of this project. The phenomena of field distribution in the conductors was also investigated. An equipment was designed and built at the preliminary stages of thework based on a flux-gate magnetometer with the ability to detect only ferrous objects.The instrument was designed such that it could be used to detect ferrous objects in the coal conveyors of power stations. The advantages of employing this detector in the power industry over the present ferrous metal electromagnetic separators were also considered. The objectives of this project culminated in the design and construction of a ferrous and non-ferrous detector with the ability to discriminate between ferrous and non-ferrous metals and to locate the objects on the conveying system. An experimental study was carried out to test the performance of the equipment in the detection of ferrous and non-ferrous objects of a given size carried on the conveyor belt. The ability of the equipment to discriminate between the types of metals and to locate the object on the belt was also evaluated experimentally. The benefits which can be gained from the industrial implementations of the equipment were considered. Further topics which may be investigated as an extension of this work are given.

Texture description and segmentation in image processing

Textured regions in images can be defined as those regions containing a signal which has some measure of randomness. This thesis is concerned with the description of homogeneous texture in terms of a signal model and to develop a means of spatially separating regions of differing texture. A signal model is presented which is based on the assumption that a large class of textures can adequately be represented by their Fourier amplitude spectra only, with the phase spectra modelled by a random process. It is shown that, under mild restrictions, the above model leads to a stationary random process. Results indicate that this assumption is valid for those textures lacking significant local structure. A texture segmentation scheme is described which separates textured regions based on the assumption that each texture has a different distribution of signal energy within its amplitude spectrum. A set of bandpass quadrature filters are applied to the original signal and the envelope of the output of each filter taken. The filters are designed to have maximum mutual energy concentration in both the spatial and spatial frequency domains thus providing high spatial and class resolutions. The outputs of these filters are processed using a multi-resolution classifier which applies a clustering algorithm on the data at a low spatial resolution and then performs a boundary estimation operation in which processing is carried out over a range of spatial resolutions. Results demonstrate a high performance, in terms of the classification error, for a range of synthetic and natural textures

The influence of fixation points on contrast detection and discrimination of patches of grating: Masking and facilitation

The use of fixation points (FPs) in visual psychophysics is common practice, though the costs and benefits of different fixation regimens have not been compared. Here we investigate the influence of several different types of FP configurations on the contrast detection of patches of sine-wave gratings. We find that for small targets (1°), the addition of a superimposed central FP can increase thresholds by a factor of 1.3 (2.5 dB) in comparison with no FP, and a factor of 1.5 (3.6 dB) in comparison with FPs that surround the target. These results are consistent with (i) a suppressive influence on the central region of the target from a central FP, and (ii) facilitatory influences from surrounding FPs. Our analysis of the slope of the psychometric function suggests that the facilitatory influence is not due to reduction of uncertainty. Plausible candidate causes for the facilitation are: (i) sensory interactions, (ii) aids to ocular accommodation and convergence, (iii) a reduction in eye-movements and (iv) more accurate placement of the observer’s window of attention. Masking by a central FP is not found for the suprathreshold task of contrast discrimination, suggesting that the masking effects of pedestal and FP do not combine linearly. This means that estimates of the level of masking produced by a contrast pedestal can depend on the details of the fixation point.

Scintillation proximity assays for the real-time detection and quantification of the progress of reactions upon solid supports

A scintillation proximity assay (SPA) has been used successfully to detect and quantify, in real-time, the kinetic progress of hydrolysis of [ H]acetate esters from scintillant-containing styrenic and poly(ethylene glycol) (PEG)-based polymer supports in both organic and aqueous media.

A unidirectional scheme for high-fidelity optical-carrier dissemination using phase-modulation, homodyne coherent-detection, and frequency entrainment

We report for the first time an ultra-stable optical-carrier dissemination technique for transmission over a 20km unidirectional fibre link. The optical-linewidth of the recovered carrier matches closely that of the original carrier. © 2014 OSA.

Detection and direction-discrimination of diotic and dichotic ramp modulations in amplitude and phase

When the source of a tone moves with respect to a listener's ears, dichotic (or interaural) phase and amplitude modulations (PM and AM) are produced. Two experiments investigated the psychophysical characteristics of dichotic linear ramp modulations in phase and amplitude, and compared them with the psychophysics of diotic PM and AM. In experiment 1, subjects were substantially more sensitive to dichotic PM than diotic PM, but AM sensitivity was equivalent in the dichotic and diotic conditions. Thresholds for discriminating modulation direction were smaller than detection thresholds for dichotic AM, and both diotic AM and PM. Dichotic PM discrimination thresholds were similar to detection thresholds. In experiment 2, the effects of ramp duration were examined. Sensitivity to dichotic AM and PM, and diotic AM increased as duration was increased from 20 ms to 200 ms. The functions relating sensitivity to ramp duration differed across the stimuli; sensitivity to dichotic PM increased more rapidly than sensitivity to dichotic or diotic AM. This was also reflected in shorter time-constants and minimum integration times for dichotic PM detection. These findings support the hypothesis that the analysis of dichotic PM and AM rely on separate mechanisms. © 2003 Acoustical Society of America.

Experiments in Detection and Correction of Russian Malapropisms by Means of the WEB

Malapropism is a semantic error that is hardly detectable because it usually retains syntactical links between words in the sentence but replaces one content word by a similar word with quite different meaning. A method of automatic detection of malapropisms is described, based on Web statistics and a specially defined Semantic Compatibility Index (SCI). For correction of the detected errors, special dictionaries and heuristic rules are proposed, which retains only a few highly SCI-ranked correction candidates for the user’s selection. Experiments on Web-assisted detection and correction of Russian malapropisms are reported, demonstrating efficacy of the described method.