UV and Visible Wavelength Reflectance Spectroscopy of Aerogel and of Stardust Grains

A new UV and visible reflectance microspectroscopy technique has been applied to cometary samples from the Stardust mission. The results have been compared with terrestrial minerals and aerogel

Wireless industrial intelligent controller for a non-linear system

Modern neural network (NN) based control schemes have surmounted many of the limitations found in the traditional control approaches. Nevertheless, these modern control techniques have only recently been introduced for use on high-specification Programmable Logic Controllers (PLCs) and usually at a very high cost in terms of the required software and hardware. This ‗intelligent‘ control in the sector of industrial automation, specifically on standard PLCs thus remains an area of study that is open to further research and development. The research documented in this thesis examined the effectiveness of linear traditional control schemes such as Proportional Integral Derivative (PID), Lead and Lead-Lag control, in comparison to non-linear NN based control schemes when applied on a strongly non-linear platform. To this end, a mechatronic-type balancing system, namely, the Ball-on-Wheel (BOW) system was designed, constructed and modelled. Thereafter various traditional and intelligent controllers were implemented in order to control the system. The BOW platform may be taken to represent any single-input, single-output (SISO) non-linear system in use in the real world. The system makes use of current industrial technology including a standard PLC as the digital computational platform, a servo drive and wireless access for remote control. The results gathered from the research revealed that NN based control schemes (i.e. Pure NN and NN-PID), although comparatively slower in response, have greater advantages over traditional controllers in that they are able to adapt to external system changes as well as system non-linearity through a process of learning. These controllers also reduce the guess work that is usually involved with the traditional control approaches where cumbersome modelling, linearization or manual tuning is required. Furthermore, the research showed that online-learning adaptive traditional controllers such as the NN-PID controller which maintains the best of both the intelligent and traditional controllers may be implemented easily and with minimum expense on standard PLCs

<i>Rehabilitation doxa</i> and practitioner judgment. An analysis of symbolic violence on health care provision in the Scottish prison system

This paper presents an analysis of the symbolic conditions which govern health care provision in the Scottish prison system. The paper considers the wider context of Scottish prisons, where health care provision follows a similar structure both in juvenile and adult prisons. Our intention is to provoke a debate about the doxa (Bourdieu, 1977), which underlies decision making in respect of health care in prison, in a political environment where pragmatism, allied to the ‘pathologisation’ of social policies, health and criminal justice has been a hegemonic force.<br/

Simulation and visualization platform integrated under hardware control systems for a reconfigurable process control

Simulation and visualization platform integrated under hardware control systems for a reconfigurable process control

GRFT – Genetic Records Family Tree Web Applet

Current software for storing and displaying records of genetic crosses does not provide an easy way to determine the lineage of an individual. The genetic records family tree (GRFT) applet processes records of genetic crosses and allows researchers to quickly visualize lineages using a family tree construct and to access other information from these records using any Internet browser. Users select from three display features: (1) a family tree view which displays a color-coded family tree for an individual, (2) a sequential list of crosses, and (3) a list of crosses matching user-defined search criteria. Each feature contains options to specify the number of records shown and the latter two contain an option to filter results by the owner of the cross. The family tree feature is interactive, displaying a popup box with genetic information when the user mouses over an individual and allowing the user to draw a new tree by clicking on any individual in the current tree. The applet is written in JavaScript and reads genetic records from a tab-delimited text file on the server, so it is cross-platform, can be accessed by anyone with an Internet connection, and supports almost instantaneous generation of new trees and table lists. Researchers can use the tool with their own genetic cross records for any sexually reproducing organism. No additional software is required and with only minor modifications to the script, researchers can add their own custom columns. GRFT’s speed, versatility, and low overhead make it an effective and innovative visualization method for genetic records. A sample tool is available at http://stanford.edu/walbot/grft-sample.html

Direct determination of absorption anisotropy in colloidal quantum rods

We propose a direct method to determine absorption anisotropy of colloidal quantum rods. In this method, the rods are aligned in solution by using an alternating electric field and we measure simultaneously the resulting average change in absorption. We show that a frequency window for the electric field exists in which the change in absorbance as a function of field strength can be analyzed in terms of the quantum-rod dipole moment and the absorption coefficient for light that is polarized parallel or perpendicular to the long axis of the rod. The approach is verified by measuring the absorbance change of CdSe rods at 400 nm as a function of field strength, where we demonstrate excellent agreement between experiment and theory. This enables us to propose improved values for the CdSe quantum-rod extinction coefficient. Next, we analyze CdSe/CdS dot-in-rods and find that the absorption of the first exciton transition is fully anisotropic, with a vanishing absorption coefficient for light that is polarized perpendicularly to the long axis of the rod

Identification of senescence and death in Emiliania huxleyi and Thalassiosira pseudonana: Cell staining, chlorophyll alterations, and dimethylsulfoniopropionate (DMSP) metabolism

We measured membrane permeability, hydrolytic enzyme, and caspase-like activities using fluorescent cell stains to document changes caused by nutrient exhaustion in the coccolithophore Emiliania huxleyi and the diatom Thalassiosira pseudonana, during batch-culture nutrient limitation. We related these changes to cell death, pigment alteration, and concentrations of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) to assess the transformation of these compounds as cell physiological condition changes. E. huxleyi persisted for 1 month in stationary phase; in contrast, T. pseudonana cells rapidly declined within 10 d of nutrient depletion. T. pseudonana progressively lost membrane integrity and the ability to metabolize 5-chloromethylfluorescein diacetate (CMFDA; hydrolytic activity), whereas E. huxleyi developed two distinct CMFDA populations and retained membrane integrity (SYTOX Green). Caspase-like activity appeared higher in E. huxleyi than in T. pseudonana during the post-growth phase, despite a lack of apparent mortality and cell lysis. Photosynthetic pigment degradation and transformation occurred in both species after growth; chlorophyll a (Chl a) degradation was characterized by an increase in the ratio of methoxy Chl a : Chl a in T. pseudonana but not in E. huxleyi, and the increase in this ratio preceded loss of membrane integrity. Total DMSP declined in T. pseudonana during cell death and DMS increased. In contrast, and in the absence of cell death, total DMSP and DMS increased in E. huxleyi. Our data show a novel chlorophyll alteration product associated with T. pseudonana death, suggesting a promising approach to discriminate nonviable cells in nature

What have we learned about COVID-19 volunteering in the UK? A rapid review of the literature.

Background Community engagement and volunteering are essential for the public response to COVID-19. Since March 2020 a large number of people in the UK have been regularly doing unpaid activities to benefit others besides their close relatives. Although most mutual aid groups emerged from local neighbourhoods and communities, official public institutions also fostered community volunteering, namely through the community champions scheme. By considering a broad definition of COVID-19 volunteering, this article describes a systematic review of the literature focused on one broad question: What have we learned about COVID-19 volunteering both at the UK national level and the more local community level? Methods A rapid review of the literature in peer-reviewed databases and grey literature was applied in our search, following the PRISMA principles. The search was conducted from 10 to 16 of October 2020, and sources were included on the basis of having been published between January and October 2020, focusing on COVID-19 and addressing community groups, volunteering groups, volunteers, or community champions in the UK. Results After initial screening, a total of 40 relevant sources were identified. From these, 27 were considered eligible. Findings suggest that food shopping and emotional support were the most common activities, but there were diverse models of organisation and coordination in COVID-19 volunteering. Additionally, community support groups seem to be adjusting their activities and scope of action to current needs and challenges. Volunteers were mostly women, middle-class, highly educated, and working-age people. Social networks and connections, local knowledge, and social trust were key dimensions associated with community organising and volunteering. Furthermore, despite the efforts of a few official public institutions and councils, there has been limited community engagement and collaboration with volunteering groups and other community-based organisations. Conclusions We identified important factors for fostering community engagement and COVID-19 volunteering as well as gaps in the current literature. We suggest that future research should be directed towards deepening knowledge on sustaining community engagement, collaboration and community participation over time, during and beyond this pandemic