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A machine vision platform for measuring imbibition of maize kernels: quantification of genetic effects and correlations with germination

BackgroundImbibition (uptake of water by a dry seed) initiates the germination process. An automated method for quantifying imbibition would enable research on the genetic elements that influence the underlying hydraulic and biochemical processes. In the case of crop research, a high throughput imbibition assay could be used to investigate seed quality topics or to improve yield by selecting varieties with superior germination characteristics.ResultsAn electronic force transducer measured imbibition of single maize kernels with very high resolution but low throughput. An image analysis method was devised to achieve high throughput and sufficient resolution. A transparent fixture held 90 maize kernels in contact with water on the imaging window of a flatbed document scanner that produced an image of the kernels automatically every 10 min for 22 h. Custom image analysis software measured the area A of each indexed kernel in each image to produce imbibition time courses. The ultimate change in area (ΔA) ranged from 19.3 to 23.4% in a population of 72 hybrids derived from 9 inbred parents. Kernel area as a function of time was fit well by Aleft( t right) = A_{f} left( {1 - e^{ - kt} } right) where Af is the final kernel area. The swelling coefficient, k, ranged from 0.098 to 0.159 h−1 across the genotypes. The full diallel structure of the population enabled maternal genotype effects to be assessed. In a separate experiment, measurements of kernels of the same 25 inbreds produced in three different years demonstrated that production and storage variables affected imbibition much less than genotype. In a third experiment, measurements of 30 diverse inbred lines showed that k varied inversely with germination time (r = − 0.7) and directly with germination percentage (r = 0.7).ConclusionsNonspecialized imaging hardware and custom analysis software running on public cyber infrastructure form a low-cost platform for measuring seed imbibition with high resolution and throughput. We measured imbibition of thousands of kernels to determine that genotype influenced imbibition of maize kernels much more than seed production and storage environments. In some hybrids, k depended on which inbred parent was maternal. Quantitative relationships between k and germination traits were discovered.

Development of a Headband for Acquisition and Analysis of Forehead EOG Signal for Driver Fatigue Detection based on Eye-Blink Patterns

Road accident occupies the number two position (next to heart attack) among the causes for sudden casualties in India. And it is the cause for 35.2 % of total accident deaths happened in 2012 [1]. Therefore, efforts for prevention of such accidents can lead to significant social and economical benefits. Body area network with wearable computing is an emerging field that can augment current practices for driver safety and accident prevention. It provides the possibility of continuous monitoring of the biological signals for detection of driver fatigue for on-line alerts. This paper presents our experience with development of a low cost system for this. It consists of a head-band housing EOG sensors connected to a small control system developed using open source hardware and the analysis software running inside the mobile phone of the driver. Detailed analysis of multi-channel EOG signal can give a number of indications of the level of driver fatigue. Unfortunately, factors like baseline drift, signal contamination, etc., make the real time analysis difficult. However, eye-blink patterns in the EOG signal stream are easy to detect and the methods for this are generally immune to many of the above problems. Our system is able to accurately capture 89% of the eye-blinks in controlled experiments where the subject is watching a video clip on a computer screen. The majority of cases where the eye-blinks were not correctly identified were the ones in which the blink event got immersed in the characteristic signal for simultaneous eye movement. These could be classified and characterized separately. Further work with field study is needed to establish efficacy of the method and modifications required to make it operationally acceptable.

Research and Analysis of a Portable Precision Temperature Sensor

Based on the excellent performance of Pt100, a portable low-cost precision temperature sensor has been designed, whose core chips are REF03, AD8603, AD7788 and precision resistors. Constant current source (CCS) for 4-wire Pt100 is constituted by REF03, AD8603 and precision resistors. AD7788 measures the differential signal on Pt100 and suppresses the common mode interference signal. Analysis software running on the micro control unit (MCU) filters the digital code from AD7788, and then calculates the current temperature value according to the resistance-temperature mathematical model of Pt100. Analysis and experimental results show that the temperature measurement accuracy of the sensor can reach ±1°C within the range of 0°C-650°C.

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The level-3 trigger at the CDF experiment at Tevatron run II

We describe the filtering and analysis software running in the Collider Detector at Fermilab (CDF) Run II Level-3 trigger, as well as the client- and event-driven data hub system. These systems constitute critical components of the data acquisition system of the CDF detector. The Level-3 trigger is responsible for reconstructing the events and forming the final trigger decision. The consumer-server/logger (CSL) system receives the accepted physics events from multiple connections and writes them to disk in multiple streams, while distributing them to online analysis programs (consumers). Since 2001, the system has been running successfully at high throughput rates: the Level-3 trigger reduces the event rate from 350 Hz to about 100 Hz with an average event size of 150 kB, while the CSL is able to process up to 22 MB/s of constant event logging. We describe these systems in detail and report on their current performance. We briefly outline upgrade plans for the remainder of Tevatron Run II.

Development of an Ultralow-Light-Level Luminescence Image Analysis System for Dynamic Measurements of Transcriptional Activity in Living and Migrating Cells

We have developed an approach to study in single living epithelial cells both cell migration and transcriptional activation, which was evidenced by the detection of luminescence emission from cells transfected with luciferase reporter vectors. The image acquisition chain consists of an epifluorescence inverted microscope, connected to an ultralow-light-level photon-counting camera and an image-acquisition card associated to specialized image analysis software running on a PC computer. Using a simple method based on a thin calibrated light source, the image acquisition chain has been optimized following comparisons of the performance of microscopy objectives and photon-counting cameras designed to observe luminescence. This setup allows us to measure by image analysis the luminescent light emitted by individual cells stably expressing a luciferase reporter vector. The sensitivity of the camera was adjusted to a high value, which required the use of a segmentation algorithm to eliminate the background noise. Following mathematical morphology treatments, kinetic changes of luminescent sources were analyzed and then correlated with the distance and speed of migration. Our results highlight the usefulness of our image acquisition chain and mathematical morphology software to quantify the kinetics of luminescence changes in migrating cells.