Co-orbiting mechanics

The motions of co-orbiting satellites is examined with reference to a free flying satellite requiring periodic servicing and an orbiting service base. The problems of differential orbit decay and nodal regression are emphasized

THE POLITICAL ECONOMY OF ENVIRONMENTAL IMPACT ASSESSMENT: INTEREST GROUPS, UNCERTAINTY AND TRANSACTIONS COSTS

Environmental Economics and Policy,

Molecular biomarkers and toxic consequences of impact by organic pollution in aquatic organisms

Organic contaminants are readily bioaccumulated by aquatic organisms. Exposure to and toxic effects of contaminants can be measured in terms of the biochemical responses of the organisms (i.e. molecular biomarkers). The hepatic biotransformation enzyme cytochrome P4501A (CYP1A) in vertebrates is specifically induced by organic contaminants such as aromatic hydrocarbons, PCBs and dioxins, and is involved in chemical carcinogenesis via catalysis of the covalent binding of organic contaminants to DNA (DNA-adducts). Hepatic CYP1A induction has been used extensively and successfully as a biomarker of organic contaminant exposure in fish. Fewer but equally encouraging studies in fish have used hepatic bulky, hydrophobic DNA-adducts as biomarkers of organic contaminant damage. Much less is known of the situation in marine invertebrates, but a CYPlA-like enzyme with limited inducibility and some potential for biomarker application is indicated. Stimulation of reactive oxygen species (ROS) production is another potential mechanism of organic contaminant-mediated DNA and other damage in aquatic organisms. A combination of antioxidant (enzymes, scavengers) and pro-oxidant (oxidised DNA bases, lipid peroxidation) measurements may have potential as a biomarker of organic contaminant exposure (particularly those chemicals which do not induce CYP1A) and/or oxidative stress, but more studies are required. Both CYP1A- and ROS-mediated toxicity are indicated to result in higher order deleterious effects, including cancer and other aspects of animal fitness

Investigation of automated task learning, decomposition and scheduling

The details and results of research conducted in the application of neural networks to task planning and decomposition are presented. Task planning and decomposition are operations that humans perform in a reasonably efficient manner. Without the use of good heuristics and usually much human interaction, automatic planners and decomposers generally do not perform well due to the intractable nature of the problems under consideration. The human-like performance of neural networks has shown promise for generating acceptable solutions to intractable problems such as planning and decomposition. This was the primary reasoning behind attempting the study. The basis for the work is the use of state machines to model tasks. State machine models provide a useful means for examining the structure of tasks since many formal techniques have been developed for their analysis and synthesis. It is the approach to integrate the strong algebraic foundations of state machines with the heretofore trial-and-error approach to neural network synthesis

PUBLIC CHOICE IN INTERNATIONAL POLLUTION

Environmental Economics and Policy,

The Influence of the COVID-19 Pandemic on At-Risk Populations Experiencing Stress and Family Violence: The Importance of An Action Model.

Abstract The paper was entitled: “The Influence of the COVID-19 Pandemic on At-Risk Populations Experiencing stress and Family Violence: The Importance of An Action Model.” As the title of the paper indicates, the paper had an ambitious task of showing how vulnerable populations, such as African Americans, because of racism, discrimination and subsequent inequities in their life experiences (such as inadequate health care, poor working conditions, a host of underlying health conditions, and potentially greater amounts of stress) are likely to become sicker with COVID-19 (higher morbidity and mortality) and, subsequently, more likely to experience higher than normal rates of family violence. The paper discussed different types of family violence, such as elder abuse, sibling abuse, child abuse and intimate partner violence. However, whatever form of family violence that is taking place in today’s society is usually intertwined with a complex mixture of factors that begin at the wider society or macro-levels, trickling down through the community and/or middle or meso-levels, and eventually landing at the individual or micro-levels of society. To better understand the complex array of societal factors, alluded to before, all of which individually and collectively help to explain how the era of the Covid-19 pandemic increased levels of stress and later the likelihood of different types of family violence, an Action Model was used as a guiding light. In essence, rather than just make alluding relational statements, as the literature warranted, steps were taken to link these important relational statements to exact sections of the Action Model depicted in the specially modified and highly illustrated Action Model of the paper. The paper closed with some recommended policy suggestions, tips, best practices and accessible resources for both stress management and family violence prevention

A new functional for charge and mass identification in Delta E-E telescopes

We propose a new functional for the charge and mass identification in Delta E-E telescopes. This functional is based on Bethe's formula, allowing safe interpolation or extrapolation in regions with low statistics. When applied to telescopes involving detectors delivering a linear response, as silicon detectors or ionization chambers, a good mass and charge identification is achieved. For other detectors, as caesium-iodide used as a final member of a telescope, a good accuracy is also obtained except in the low residual energy region. A good identification is however recovered if a non-linear energy dependence of the light output is included.Comment: 16 pages, 8 figures, LaTeX2e + EPS figures reduced in size Submitted to Elsevie