Non-Market Valuation and the Household

The purpose of this paper is to describe the implications of the collective model of household behavior for the methods used to estimate the economic value of non-marketed environmental resources. The effects of public good and risk are considered, along with revealed and stated preference methods. To the extent the collective framework is adopted, then recover of individual preferences from household behavior requires distinguishing how preference and within household income allocations affect choices.

Benefit Transfer as Preference Calibration

This paper proposes and illustrates the use of a new approach to benefit transfer for the non-market valuation of environmental resources. It treats transfer as an identification problem that requires assessing whether available benefit estimates permit the parameters of a preference function to be identified. The transfer method proposed uses these identifying restrictions to calibrate preference parameters and bases the benefit estimates on that preference function. The approach is illustrated using travel cost, hedonic and contingent valuation estimates, as well as combinations of estimates. It has three potential advantages over conventional practice: (1) it allows multiple, potentially overlapping estimates of the benefits of an improvement in environmental quality to be combined consistently; (2) it assures the transferred estimates of the benefits attributed to a proposed change can never exceed income; and (3) it provides a set of additional "outputs" that offer plausibility checks of the benefit transfers.

Chromosome Aberrations in Astronauts

A review of currently available data on in vivo induced chromosome damage in the blood lymphocytes of astronauts proves that, after protracted exposure of a few months or more to space radiation, cytogenetic biodosimetry analyses of blood collected within a week or two of return from space provides a reliable estimate of equivalent radiation dose and risk. Recent studies indicate that biodosimetry estimates from single spaceflights lie within the range expected from physical dosimetry and biophysical models, but very large uncertainties are associated with single individual measurements and the total sample population remains low. Retrospective doses may be more difficult to estimate because of the fairly rapid time-dependent loss of "stable" aberrations in blood lymphocytes. Also, biodosimetry estimates from individuals who participate in multiple missions, or very long (interplanetary) missions, may be complicated by an adaptive response to space radiation and/or changes in lymphocyte survival and repopulation. A discussion of published data is presented and specific issues related to space radiation biodosimetry protocols are discussed

Dose Response for Chromosome Aberrations in Human Lymphocytes and Fibroblasts after Exposure to Very Low Doses of High LET Radiation

The relationship between biological effects and low doses of absorbed radiation is still uncertain, especially for high LET radiation exposure. Estimates of risks from low-dose and low-dose-rates are often extrapolated using data from Japanese atomic bomb survivors with either linear or linear quadratic models of fit. In this study, chromosome aberrations were measured in human peripheral blood lymphocytes and normal skin fibroblasts cells after exposure to very low dose (1-20 cGy) of 170 MeV/u Si-28- ions or 600 MeV/u Fe-56-ions. Chromosomes were analyzed using the whole chromosome fluorescence in situ hybridization (FISH) technique during the first cell division after irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving greater than 2 breaks in 2 or more chromosomes). The curves for doses above 10 cGy were fitted with linear or linear-quadratic functions. For Si-28- ions no dose response was observed in the 2-10 cGy dose range, suggesting a non-target effect in this range

The Biological Effectiveness of Different Radiation Qualities for the Induction of Chromosome Damage in Human Lymphocytes

Chromosome aberrations were measured in human peripheral blood lymphocytes after in vitro exposure to Si-28-ions with energies ranging from 90 to 600 MeV/u, Ti-48-ions with energies ranging from 240 to 1000 MeV/u, or to Fe-56-ions with energies ranging from 200 to 5,000 MeV/u. The LET of the various Si beams in this study ranged from 48 to 158 keV/ m, the LET of the Ti ions ranged from 107 to 240 keV/micron, and the LET of the Fe-ions ranged from 145 to 440 keV/ m. Doses delivered were in the 10- to 200-cGy range. Dose-response curves for chromosome exchanges in cells at first division after exposure, measured using fluorescence in situ hybridization (FISH) with whole-chromosome probes, were fitted with linear or linear-quadratic functions. The relative biological effectiveness (RBE) was estimated from the initial slope of the dose-response curve for chromosome damage with respect to gamma-rays. The estimates of RBEmax values for total chromosome exchanges ranged from 4.4+/-0.4 to 31.5+/-2.6 for Fe ions, 21.4+/-1.7 to 28.3+/-2.4 for Ti ions, and 11.8+/-1.0 to 42.2+/-3.3 for Si ions. The highest RBEmax value for Fe ions was obtained with the 600 MeV/u beam, the highest RBEmax value for Ti ions was obtained 1000 MeV/u beam, and the highest RBEmax value for Si ions was obtained with the 170 MeV/u beam. For Si and Fe ions the RBEmax values increased with LET, reaching a maximum at about 180 keV/micron for Fe and about 100 keV/micron for Si, and decreasing with further increase in LET. Additional studies for low doses Si-28-ions down to 0.02 Gy will be discussed

Simulations of DSB Yields and Radiation-induced Chromosomal Aberrations in Human Cells Based on the Stochastic Track Structure iIduced by HZE Particles

The formation of doublestrand breaks (DSBs) and chromosomal aberrations (CAs) is of great importance in radiation research and, specifically, in space applications. We are presenting a new particle track and DNA damage model, in which the particle stochastic track structure is combined with the random walk (RW) structure of chromosomes in a cell nucleus. The motivation for this effort stems from the fact that the model with the RW chromosomes, NASARTI (NASA radiation track image) previously relied on amorphous track structure, while the stochastic track structure model RITRACKS (Relativistic Ion Tracks) was focused on more microscopic targets than the entire genome. We have combined chromosomes simulated by RWs with stochastic track structure, which uses nanoscopic dose calculations performed with the MonteCarlo simulation by RITRACKS in a voxelized space. The new simulations produce the number of DSBs as function of dose and particle fluence for highenergy particles, including iron, carbon and protons, using voxels of 20 nm dimension. The combined model also calculates yields of radiationinduced CAs and unrejoined chromosome breaks in normal and repair deficient cells. The joined computational model is calibrated using the relative frequencies and distributions of chromosomal aberrations reported in the literature. The model considers fractionated deposition of energy to approximate dose rates of the space flight environment. The joined model also predicts of the yields and sizes of translocations, dicentrics, rings, and more complextype aberrations formed in the G0/G1 cell cycle phase during the first cell division after irradiation. We found that the main advantage of the joined model is our ability to simulate small doses: 0.050.5 Gy. At such low doses, the stochastic track structure proved to be indispensable, as the action of individual deltarays becomes more important

M-FISH Analysis of Chromosome Aberrations in Human Fibroblast Cells After In Vitro Exposure to Low- and High-LET Radiation

The recently commercialized multiplex fluorescence in situ hybridization (m-FISH) technique, which allows human chromosomes to be painted in 24 different colors, was used to analyze chromosome aberrations in diploid human fibroblast cells after in vitro radiation exposure. Confluent flasks of a normal primary fibroblast cell line (AG 1522) were irradiated at high dose rates with either gamma rays or 200 MeV/nucleon Fe ions (LET = 440 keV/micron), incubated at 37 C for 24 hours after exposure, and subsequently subcultured. A chemically induced premature chromosome condensation technique was used to collect chromosome samples 32 hours after subculture. Results showed that the fraction of exchanges which were identified as complex, i.e. involving misrejoining of three or more DSB, were higher in the Fe-irradiated samples compared with the gamma-irradiated samples, as has been shown previously using FISH with one or two painted chromosomes . The ratios of complex/simple type exchanges were similar for samples irradiated with 0.7 Gy and 3 Gy of Fe ions, although exchanges involving five or more breaks were found only in 3 Gy irradiated samples. The fraction of incomplete exchanges was also higher in Fe- than gamma-irradiated samples. Data on the distribution of individual chromosome involvement in interchromosomal exchanges will be presented

The Research Informed Teaching Project at Staffordshire University 2013-2016: Conference Paper: Enhancing Students’ Skills Development in Contract Law through an Online Simulation (MLX)

Description of Session & Abstract. In this session at the Association of Law Teachers (ALT) annual conference 2016, members of the RiT project team and colleagues from Pearson Education, notably Kerry George and Prof. Stephen Gomez - who have been working with the SU RiT team - presented preliminary finding from a collaborative study of the use of a new digital, online learning resource called MyLegalExperience (MLX) to assist student learning in Contract Law. The presentation drew on the work of Judith Tillson, lead researcher for the work being done with Pearson on MLX, and Prof Stephen Gomez. The session started with some background, describing the challenges faced with traditional teaching methods of applying Contract Law to practical advice needs for clients; and then explaining the use of an online system to address these challenges. Emphasis was placed on how collaboration between tutor, student and content provider can be facilitated through technology. As well as a demonstration, questions from delegates were taken by the presenters. Abstract. The RiT project has been interested in a range of issues since it started in 2013, including the support that Law students get from on-line systems and services which support their research, teaching, and learning, and the application of knowledge. Previous presentations by the team at ALT conferences, including those at Nottingham and Cardiff, have been concerned with the use of on-lines systems and the development and deployment of research and research-related skills, and assessment aspects. The MLX project focuses on the problems students can have with putting their knowledge into practice, for instance when advising clients about legal matters. The context is that students are requesting more opportunities to practice and to obtain greater feedback, including more individual, personalised comments from tutors. With the increase in student numbers, all these requirements have an impact on tutor workload. New internet technologies have the potential for addressing these issues but lecturers either do not have the time or web skills to produce sophisticated online systems at a standard expected by their students who are used to professional software on the internet. The RiT project team, notably Judith Tillson, have teamed up with Pearson, the education publishers, to consider these challenges, and to trial MLX. The MLX system provides an online simulation designed to support students’ engagement and skills development in Contract Law across 6 topics. However, only two topics have been used in this particular trial, as it has been managed by Judith. In each topic, students play a legal advisory role, and complete practical tasks in response to the issues raised by a fictional client. Each topic consists of four scaffolded activities that build up in complexity as students work through them. The activities are: 1. Issue spotting - students answer a series of self-assessed MCQs (multiple choice questions) to identify the legal issues and legal principles from the facts related to Contract Law. 2. Analysing the Law - students fill in the blanks to identify the legal issues and legal principles from the facts. 3. Applying legal advice – this involves a practical task designed to put knowledge into practice by students uploading a piece of work which is then marked by the lecturer who gives feedback to be used to feed forward as assessment for learning as the basis of the fourth activity below. 4. Reflection- model answer and reflective MCQs to compare work completed in activity 3 to the model answer to facilitate self-assessment as a link to self-organised learning. Judith and the team have been exploring the effectiveness or efficacy of MLX in supporting learning through a simulation in the manner described above. Though we are using a specific learning resource (i.e. MLX) in the study, it is intended that we will establish a pedagogy that can be applied in other contexts. The project has been run by Judith in a live module in 2015-16 using a mix of qualitative and quantitative methods to assess students’ attitudes and perspectives, as well as data analytics to measure student engagement and performance both in MLX and in summative module assignments. Judith has also been using an innovative Twitter approach to charting student attitudes throughout their usage of MLX. Project Findings. Preliminary findings were provided in the course of the presentation. Further work is being undertaken by Judith and Christine, and it is hoped the results will feature in an article in The Law Teacher in 2017-18 and in other outputs