Performance testing of lidar receivers

In addition to the considerations about the different types of noise sources, dynamic range, and linearity of a lidar receiver, one requires information about the pulse shape retaining capabilities of the receiver. For this purpose, relatively precise information about the height resolution as well as the recovery time of the receiver, due both to large transients and to fast changes in the received signal, is required. As more and more analog receivers using fast analog to digital converters and transient recorders will be used in the future lidar systems, methods to test these devices are essential. The method proposed for this purpose is shown. Tests were carried out using LCW-10, LT-20, and FTVR-2 as optical parts of the optical pulse generator circuits. A commercial optical receiver, LNOR, and a transient recorder, VK 220-4, were parts of the receiver system

Imipenem resistance in clinical Escherichia coli from Qom, Iran

OBJECTIVE: The emergence of metallo-\u3b2-lactamase-producing Enterobacteriaceae is a worldwide health concern. In this study, the first evaluation of MBL genes, bla IMP and bla VIM , in Escherichia coli resistant to imipenem isolated from urine and blood specimens in Qom, Iran is described. Three hundred urine and blood specimens were analysed to detect the presence of E. coli. Resistance to imipenem and other antimicrobials was determined by disk diffusion and MIC. MBL production was screened using CDDT. PCR was also carried out to determine the presence of bla IMP and bla VIM genes in imipenem-resistant isolates. RESULTS: In total, 160 E. coli isolates were collected from March to May 2016. According to disk diffusion, high-level of resistance (20%) to cefotaxime was observed, whereas the lowest (1%) was detected for tetracycline. In addition, five isolates showed resistance to imipenem with a MIC\u2009 65\u20094 \ub5g/mL. CDDT test confirmed that five isolates were MBL-producing strains, but no bla IMP and bla VIM genes were detected. Results of this study show a very low level of resistance to imipenem in our geographical area

Search of low contrast liver lesions in abdominal CT: an eye-­‐tracking study in volumetric images

Eye-­‐tracking studies can be particularly effective in improving tumor detection by radiologists. Several studies have attempted to characterize the ability of radiologists to search for and recognize different targets in various imaging modalities. However, few studies have associated eye-­‐tracking experiments with scrolling volumetric images such as CT. Among them, a recent study on the reading of chest CT images showed that the detection strategies of radiologists could be classified in two categories, the "drillers" and the "scanners", according to an eye movement index (EMI), which quantifies the tendency of radiologists to perform large saccades in the investigated organ. However, the EMI doesn’t take into account how radiologists scroll through the different volumetric data slices. We propose to add this information through the "number of courses", defined as the number of times a reader scrolls in a given direction during the analysis of the image. Our study aims to document this quantity and show how it could complement the EMI in order to quantify the strategy of the radiologist. We considered a set of 15 asymptomatic liver CT images in which we inserted 1 to 5 metastases of two different contrast amplitudes. Twenty radiologists were asked to search for the metastases while their eye-­‐gaze was followed by an eye-­‐tracker. The drillers are defined a going back and forth through the image stack, each time to exploring a different area in each image. We identified them as having a low EMI (e) and a large number of courses (C). The scanners are defined as scrolling coherently through the stack of images and exploring each image slice one after the other. They tend to have a high EMI (E) and a low number of courses (c). Interestingly, we observed that radiologists with a larger number of courses (eC and EC) tended to cover more volume in more time than radiologists with a lower number of courses (ec and ec). They found more metastasis and made less search errors than those with lower number of courses, especially when searching for lower contrast signals. Therefore, a driller defined by a low EMI and a high number of courses (eC) tend to be more efficient than scanners. Our results show that for when the task becomes more difficult, the radiologists can improve their effectiveness by applying a strategy of a driller defined as an EMI and a higher number of courses. This could be used teaching resident radiologists

Optical generation and wireless transmission of 60 GHz OOK signals using gain switched laser

We present a novel, simple and cost effective system for optical millimeter-wave generation and transmission of 3 Gbps data based on gain switching. System performance has been investigated, including wireless transmission and power budget analysis