In the recent SARS-CoV-2 pandemic, public health experts have emphasized testing, tracking infected people, and tracing their contacts as an effective strategy to reduce the spread of the virus. Several diagnostic methods are reported for detecting the coronavirus in clinical, research, and public health laboratories. Some tests detect the infection directly by detecting the viral RNA and other tests detect the infection indirectly by detecting the host antibodies. A diagnostic test during the pandemic should help make an appropriate clinical decision in a short period of time. Recently reported diagnostic methods for SARS-CoV-2 have varying throughput, batching capacity, requirement of infrastructure setting, analytical performance, and turnaround times ranging from a few minutes to several hours. These factors should be considered while selecting a reliable and rapid diagnostic method to help make an appropriate decision and prompt public health interventions. This paper reviews recent SARS-CoV-2 diagnostic methods published in journals and reports released by regulatory agencies. We compared the analytical efficiency including limit of detection, sensitivity, specificity, and throughput. In addition, we also looked into ease of use, affordability, and availability of accessories. Finally, we discuss the limitations of the methods and provide our perspectives on priorities for future test development.

The development of navigation tools for people who are visually impaired had become an important concern in the research area of assistive technologies. This paper gives a comprehensive review of different articles published in the area of navigation solutions for people who are visually impaired. Unlike other review papers, this review considers major solutions that work in both the indoor or/and outdoor environments which are based on different technology. From the review, it became clear that the navigation systems proposed for the target users lack some core features that are quite important for independent navigation. Also, there can be instances in which humanitarian conditions also have to be considered in the navigation system design. Based on these findings, a set of recommendations are also given which can be considered in the future design of navigation systems for blind and visually impaired people.

International audienceThis paper proposes a one-shot six-channel multispectral color image acquisition system using a stereo camera and a pair of optical filters. The two filters from the best pair, selected from among readily available filters such that they modify the sensitivities of the two cameras in such a way that they produce optimal estimation of spectral reflectance and/or color, are placed in front of the two lenses of the stereo camera. The two images acquired from the stereo camera are then registered for pixel-to-pixel correspondence. The spectral reflectance and/or color at each pixel on the scene are estimated from the corresponding camera outputs in the two images. Both simulations and experiments have shown that the proposed system performs well both spectrally and colorimetrically. Since it acquires the multispectral images in one shot, the proposed system can solve the limitations of slow and complex acquisition process, and costliness of the state of the art multispectral imaging systems, leading to its possible uses in widespread applications

Multispectral color imaging is a promising technology, which can solve many of the problems of traditional RGB color imaging. However, it still lacks widespread and general use because of its limitations. State of the art multispectral imaging systems need multiple shots making it not only slower but also incapable of capturing scenes in motion. Moreover, the systems are mostly costly and complex to operate. The purpose of the work described in this paper is to propose a one-shot six-channel multispectral color image acquisition system using a stereo camera or a pair of cameras in a stereoscopic configuration, and a pair of optical filters. The best pair of filters is selected from among readily available filters such that they modify the sensitivities of the two cameras in such a way that they get spread reasonably well throughout the visible spectrum and gives optimal reconstruction of spectral reflectance and/or color. As the cameras are in a stereoscopic configuration, the system is capable of acquiring 3D images as well, and stereo matching algorithms provide a solution to the image alignment problem. Thus the system can be used as a "two-in-one" multispectral-stereo system. However, this paper mainly focuses on the multispectral part. Both simulations and experiments have shown that the proposed system performs well spectrally and colorimetrically.

Nepal has high potential for hydropower due to glaciers in the Himalayas, regular monsoon rain and local topography. Himalayan Rivers contain large quantities of sediment with hard abrasive particles, which is a hurdle for the economic exploitation of hydropower resources. Erosion of the earth's surface takes place because of influence of climatic, tectonic and human activities. Almost all the power plants in the Himalayan region are affected by excessive sediment in rivers that reduce the life of plants either by filling reservoirs or by erosion of turbine components. The design and operation of headwork components in hydropower plants can only manipulate sediment particle size and hence only sediment concentration in the water. The erosion of hydraulic machinery depends on eroding particles, that is, their size, shape and hardness; on substrates, their chemistry, elastic properties, surface hardness and surface morphology; and on operating conditions, velocity, impingement angle and concentration. The shape, size and mineral content of sediment vary at different locations of the same river system depending on distance traversed by particles, gradient of the river and the geological formation of the river course and catchment areas. The Khimti hydropower project in Nepal represents a typical high head power plant in the Himalayan River that is affected by river sediment. Erosion tests of turbine material carried out at Kathmandu University revealed the dependence of erosion rate on mineral content. The erosion tests have shown trends relative to the quartz content present in samples from river basins in different parts of the country. There was some indication that the shape of particles had some effect. Sediments in the hydropower projects are normally considered as a burden, but there is scope for industrial use of these sediments.

Abstract-In this paper we will show that using Principle Component Analysis (PCA) on accelerometer based gait data will give a large improvement on the performance. On a dataset of 720 gait samples (60 volunteers and 12 gait samples per volunteer) we achieved an EER of 1.6% while the best result so far, using the Average Cycle Method (ACM), gave a result of nearly 6%. This tremendous increase makes gait recognition a viable method in commercial applications in the near future.

Abstract:Increasing the number of imaging channels beyond the conventional three has been shown to be beneficial for a wide range of applications. However, it is mostly limited to imaging in a controlled environment, where the capture environment (illuminant) is known a priori. We propose here a novel system and methodology for multispectral imaging in an uncontrolled environment. Two images of a scene, a normal RGB and a filtered RGB are captured. The illuminant under which an image is captured is estimated using a chromagenic based algorithm, and the multispectral system is calibrated automatically using the estimated illuminant. A 6-band multispectral image of a scene is obtained from the two RGB images. The spectral reflectances of the scene are then estimated using an appropriate spectral estimation method. The proposed concept and methodology is generic one, as it is valid in whatever way we acquire the two images of a scene. A system that can acquire two images of a scene can be realized, for instance in two shots using a digital camera and a filter, or in a single shot using a stereo camera, or a custom color filter array design. Simulation experiments using a stereo camera based system confirms the effectiveness of the proposed method. This could be useful in many imaging applications and computer vision.

Background Laparoscopic cholecystectomy has become standard method for treating gallstone. However, different centres have reported different complications and conversion rate. The objective of this study was to evaluate complications and conversion of laparoscopic cholecystectomy into open cholecystectomy in Dhulikhel Hospital, Kathmandu University, Nepal. Methods Files of all patients who had laparoscopic cholecystectomy from January 2005 to December 2009 were reviewed. Out of 119 laparoscopic cholecystectomy cases, 102 were included in the study as complete information was lacking in the rest. Results Out of 102 cases, 80 were female. Symptomatic cholelithiasis were 76.47%. The mean hospital stay was 2.48 days. Postoperative complications occured in 5.88% patients. Conversion rate to open cholecystectomy was 3.92%. Conclusions Laparoscopic cholecystectomy is a reliable and safe surgery. With growing experience in laparoscopic technique, it is possible to bring complications and conversion rate to minimum. However, there will be no significant improvements once learning curve is reached. Rather, the nature of biliary injury may become more severe.http://dx.doi.org/10.3126/kumj.v8i4.6232 Kathmandu Univ Med J 2010;8(4):367-9