Geometric consistency and stability of consumer-grade digital cameras for accurate spatial measurement

This is a journal article. It was published in the journal, The Photogrammetric Record [© Remote Sensing and Photogrammetry Society and Blackwell Publishing Ltd] and the definitive version is available at: http://www3.interscience.wiley.com/journal/118539355/homeIt is known that uncertain internal geometry of consumer-grade digital cameras limits the accuracy of data that can be extracted. These cameras can be calibrated, but the validity of calibration data over a period of time should be carefully assessed before subsequent photogrammetric measurement. This paper examines the geometric stability and manufacturing consistency of a typical low-cost digital camera (Nikon Coolpix 5400) by estimating the degree of similarity between interior orientation parameters (IOP), established over a oneyear period. Digital elevation models (DEMs) are extracted with differing interior orientation parameters (IOP) sets and accuracies are compared using data obtained from seven identical cameras. An independent self-calibrating bundle adjustment (GAP) and the Leica Photogrammetry Suite (LPS) software were used to provide these datasets. Results are presented that indicate the potential of these cameras to maintain their internal geometry in terms of temporal stability and manufacturing consistency. This study also identifies residual systematic error surfaces or “domes”, discernible in “DEMs of difference”. These are caused by slightly inaccurately estimated lens distortion parameters, which effectively constrain the accuracies achievable with this class of sensor

Cross-Talk between the Cellular Redox State and the Circadian System in Neurospora

The circadian system is composed of a number of feedback loops, and multiple feedback loops in the form of oscillators help to maintain stable rhythms. The filamentous fungus Neurospora crassa exhibits a circadian rhythm during asexual spore formation (conidiation banding) and has a major feedback loop that includes the FREQUENCY (FRQ)/WHITE COLLAR (WC) -1 and -2 oscillator (FWO). A mutation in superoxide dismutase (sod)-1, an antioxidant gene, causes a robust and stable circadian rhythm compared with that of wild-type (Wt). However, the mechanisms underlying the functions of reactive oxygen species (ROS) remain unknown. Here, we show that cellular ROS concentrations change in a circadian manner (ROS oscillation), and the amplitudes of ROS oscillation increase with each cycle and then become steady (ROS homeostasis). The ROS oscillation and homeostasis are produced by the ROS-destroying catalases (CATs) and ROS-generating NADPH oxidase (NOX). cat-1 is also induced by illumination, and it reduces ROS levels. Although ROS oscillation persists in the absence of frq, wc-1 or wc-2, its homeostasis is altered. Furthermore, genetic and biochemical evidence reveals that ROS concentration regulates the transcriptional function of WCC and a higher ROS concentration enhances conidiation banding. These findings suggest that the circadian system engages in cross-talk with the cellular redox state via ROS-regulatory factors

Unrolling the Archives’ Thread: Epilepsy and Epileptics at the National Hospital for the Paralysed and Epileptic

The third chapter of the book proceeds to the detailed presentation and analysis of the medical files of John Hughlings Jackson’s epileptic patients, who were hospitalized at the National Hospital for the Paralysed and Epileptic, during the period 1870–1895. More particularly, it aims at a chronological presentation of the archival data. For this reason, it is divided into four subperiods: (i) 1870–1879, (ii) 1880–1885, (iii) 1886–1890 and (iv) 1891–1895. From this perspective, it focuses on the diachronic, quantitative presentation of a variety of elements: epileptic patients’ gender, their age, their marital status, the time of being ill before their admittance to the National Hospital, the length of their hospitalization, their occupation, their address of residence, the means of treatment and the result of hospitalization. The meticulous reference to these data is going to facilitate their qualitative, sociological and epistemological, analysis that is going to follow in the next two chapters of the book. © 2015, Springer International Publishing Switzerland