Decimal digit generator for commutated data: A Concept

Perform analog-to-digital conversion on input signal with staircase circuit having 10% resolution, convert digital result to analog voltage, subtract it from original input signal; read out feedback signals as decimal digit representation during one clock phase and servo-error difference between input and feedback as analog portion during following clock phase

Drag-compensated, precision-powered hinge system

The design of a high precision powered hinge is complicated by the unavoidable presence of parasitic drag torque resulting mainly from friction and transfer of power, signals, and fluids across the hinge. Regardless of the type of drive system selected, it is impossible to completely eliminate all parasitic drag. However, the mechanism described here comes very close to providing a drag free system. All sources of parasitic drag torque are collected on a shaft which is powered by an electric motor independent of the main hinge drive. Under control of a sensor, the electric motor applies a compensating torque equal to that of the parasitic drag torque, allowing the main hinge drive to operate in a practically drag free environment with very high positioning precision

Proportional pulsed pilot valve

Proportional pulsed pilot valve using conventional efficient solenoid valve for pilot stage provides proportional thrust control for cold gas thrusters with zero leakage of main stage

Upper secondary students’ thinking pathways in cell membrane biology – an evidence-based development and evaluation of learning activities using the Model of Educational Reconstruction

This study reports on the theoretical- and empirical-based design and evaluation of cell membrane biology learning activities within the Model of Educational Reconstruction and experiential realism. First, we designed analogy-based learning activities by considering students’ and scientists’ conceptions as described in the literature. Secondly, we carried out two video-taped teaching experiments to study students’ learning processes when interacting with the learning activities. Interpreting students’ conceptual development as thinking pathways enabled us to identify and understand the roots of their learning difficulties. Due to inherent ontological and epistemological presumptions, the students had difficulties in understanding that cell membrane structure determines their two-fold function: to separate and to connect environments in order to maintain living processes. The multiple analogies we employed helped foster conceptual development because they highlighted aspects of the concrete everyday experiences the students already had, but had not thought about. As a result of the learning activities, the students revised their conceptions regarding the terms barrier, gatekeeper and environment and connected these to a more coherent conceptual structure of cell membrane biology. Methods and outcomes of the study may contribute to a better understanding of how this important concept can be brought to science classrooms

Optical Polarization of 52 Radio-Loud QSOs and BL Lac Objects

Polarization measurements are presented for 52 radio-loud QSOs and BL Lac objects. For 9 highly polarized (p >3%) AGN, these are the first published polarization measurements. Of these 9, 7 are highly-polarized QSOs (HPQs), one is a BL Lac object and another is a likely BL Lac object. Polarization variability is confirmed for some of these new and previously known highly-polarized AGN. While 6 of the HPQs have flat radio spectra are almost certainly blazars, PKS 1452-217 is probably a new member of the rare class of radio-loud QSOs that show high polarization by scattering, and is therefore important for testing orientation Unified Schemes. In competition for the highest redshift HPQ are the well-observed QSO PKS 0438-43 at z = 2.85, with maximum p = 4.7%, and PKS 0046-315 at z = 2.72, for which we find p = 13%.Comment: 6 pages. Astronomical Journal, in pres

A comparative study of Mackay-Marg, Durham-Langham and Tonomat tonometry

A comparative study of Mackay-Marg, Durham-Langham and Tonomat tonometr

Upper secondary students’ thinking pathways in cell membrane biology–an evidence-based development and evaluation of learning activities using the Model of Educational Reconstruction

publishedVersio

An Evaluation of Retinal Imaging Technology for 4-H Beef and Sheep Identification

The study reported here evaluated retinal imaging technology as a means of permanent identification of 4-H beef and sheep. The OptiReader» Device was used to capture digital images of 491 beef and 220 sheep during 4-H enrollment. A total of 317 beef and 159 sheep were re-imaged. The on-site visual verification rate was 96.2% for beef and 100% for sheep. A visual verification exercise showed that individuals could identify a pair of retinal images as a match 98.6 % of the time for beef. Retinal imaging is a viable method for enrolling beef and sheep

Geographically-weighted regression of knowledge and behaviour determinants to anti-malarial recommending and dispensing practice among medicine retailers in western Kenya: capacitating targeted interventions

Background Most patients with malaria seek treatment first in retail drug shops. Myriad studies have examined retailer behaviours and characteristics to understand the determinants to these behaviours. Geospatial methods are helpful in discovering if geographic location plays a role in the relationship between determinants and outcomes. This study aimed to discover if spatial autocorrelation exists in the relationship between determinants and retailer behaviours, and to provide specific geographic locations and target behaviours for tailoring future interventions. Methods Retailer behaviours and characteristics captured from a survey deployed to medicine retailers in the Webuye Demographic and Health Surveillance Site were analysed using geographic weighted regression to create prediction models for three separate outcomes: recommending the first-line anti-malarial therapy to adults, recommending the first-line anti-malarial therapy to children, and selling that therapy more than other anti-malarials. The estimated regression coefficients for each determinant, as well as the pseudo R2 values for each final model, were then mapped to assess spatial variability and local areas of best model fit. Results The relationships explored were found to be non-stationary, indicating that spatial heterogeneity exist in the data. The association between having a pharmacy-related health training and recommending the first-line anti-malarial treatment to adults was strongest around the peri-urban centre: comparing those with training in pharmacy to those without training (ORæ=æ5.75, pæ=æ0.021). The association between knowing the first-line anti-malarial and recommending it to children was strongest in the north of the study area compared to those who did not know the MOH-recommended anti-malarial (ORæ=æ2.34, pæ=æ0.070). This is also the area with the strongest association between attending a malaria workshop and selling the MOH-recommended anti-malarial more than other anti-malarials, compared to retailers who did not attend a workshop (ORæ=æ2.38, pæ=æ0.055). Conclusion Evidence suggests that spatial heterogeneity exists in these data, indicating that the relationship between determinants and behaviours varies across space. This is valuable information for intervention design, allowing efforts to focus on those factors that have the strongest relationship with their targeted behaviour within that geographic space, increasing programme efficiency and cost-effectiveness