How Should Governments Address High Levels of Natural Radiation and Radon--Lessons from the Chernobyl Nuclear Accident and Ramsar, Iran

The authors discuss the high levels of natural background radiation in Ramsar, Iran, and offer data indicating that this has had little effect on the health of Ramsar\u27s inhabitants. The authors then examine the implications their research could have for public health policy

The need for national diagnostic reference levels: Entrance surface dose measurement in intraoral radiography

Background: Intraoral radiographies are the most frequent X-ray examinations in humans. According to International Commission on Radiation Protection (ICRP) recommendations, the selection of a diagnostic reference level (DRL) should be specific to a country or region. Critical organs such as thyroid gland are exposed to X-rays in intraoral radiography and these exposures should be kept as low as reasonably achievable. To assist the development of DRLs for intraoral radiography, a National Radiation Protection Department-sponsored pilot study was carried out. Materials and Methods: Thermoluminescent dosimetry (TLD) is widely acknowledged to be the recommended method for measuring entrance surface doses (ESD). In this study, ESD was measured using LiF thermoluminescent dosimeters (TLD-100) on the skin (either mandibular or maxillary arcs) of 40 patients. Three TLD chips were placed on the skin of each patient. The doses were averaged for each radiography and mean ESD of all patients calculated. Results: The mean ± SD entrance surface dose at the center of the beam on the patients' skin in intraoral radiography was 1.173 ± 0.606 mGy (ranged from 0.01 to 0.40 mGy). The mean ESD for male and female patients were 1.380 ± 0.823, and 1.004 ± 0.258 respectively. No statistically significant difference was found between these means. Despite its necessity, in national level, there is no published data on the diagnostic reference levels for intraoral radiography. However, the results obtained in this study are lower than those reported by investigators in other countries. Conclusion: In IR Iran, due to lack of large scale studies, no diagnostic reference levels have been set for X-ray diagnostic procedures. Due to lack of national diagnostic reference levels, it is not possible to clarify whether in intraoral radiographies any dose reduction techniques are needed. We intend to perform similar nationwide studies to set the diagnostic reference level for intraoal radio graphy

Entrance surface dose measurement on the thyroid gland in orthopantomography: The need for optimization

Background: The anatomic position and proven radiosensitivity of the thyroid make it an organ of concern in dental X-ray examinations. A National Radiation Protection Department (NRPD)-sponsored pilot study carried out in the Dental Radiology Department of RUMS., to assess if the radiation dose in panoramic radiographies could be reduced without significant impairment of the subjective image quality. Materials and Methods: Thermoluminescent dosimetry (TLD) is widely acknowledged to be the recommended method for measuring entrance surface doses (ESD). In this study, ESD was measured using LiF thermoluminescent dosimeters (TLD-100) on the thyroid of 40 patients who had referred to the School of Dentistry, Rafsanjan University of Medical Sciences. Patients were not exposed to any additional radiation and the radiographs were used for diagnostic purposes. TLDs were calibrated with radiation energies similar to those commonly used in orthopantomography. Results: The overall mean ESD on the thyroid in orthopantomography was 0.071 ± 0.012 mGy (ranged from 0.01 to 0.40 mGy). The mean ESD for radiographies performed with 66 kVp (20 patients) and 68 kVp (20 patients) were 0.072 ± 0.019, and 0.070 ± 0.016 respectively. No statistically significant difference was found between these means. Conclusions: The measured surface doses in our study are inconsistent with the only one already reported about the same experiment. However, due to lack of national diagnostic reference levels for orthopantomography, it is not clear whether in case of the PM 2002 CC unit used in this experiment, reducing the radiation dose to a level that still keeps a diagnostically acceptable image quality is necessary

The relationship between management accounting, profitability and operations in an uncertain world : evidence from literature and practice

At the heart of many core Management Accounting (MA) practices there is a potential mismatch between the assumption of a materially predictable future operating environment, and the reality of an uncertain and unpredictable world. Practices such as budgets, product costing, investment appraisal and financial projections, aimed at facilitating the achievement of profitability goals, are based on the assumption that the future is sufficiently stable and predictable to benefit from analytical calculation. However, we live in a world where the future can be uncertain, unstable and unpredictable. Does this mean that when operating conditions become unstable, unpredictable and uncertain many MA practices lose their core modus operandi? This thesis addresses this issue through an interwoven mix of a longitudinal case study and literature reviews spread over three projects. The case study was longitudinal and based on in depth participant observation. The firm involved was a £38m UK logistics company. The study benefited from totally unrestricted access to all strategic, financial and operational activities and data, because of the author’s senior role in the firm. The literature review was conducted using a targeted systematic review (Tranfield and Denyer, 2003) supported by additional narrative reviews. This synoptic paper provides a reflective synthesis of the findings and the contribution of the three projects which together constitute the research. Four core interlinked findings emerged from the study, based on the assumption that the achievement of profitability goals is the primary goal of the organisation. First, building on the proposals of (Otley, 1999) a framework showing the relationship between MA, profitability, operations and uncertainty is proposed. It demonstrates how MA financialises operations by creating a parallel financial space to the operational space; how profitability outcomes result from the financial consequences of operational actions; how the role of MA is to inform and control operational actions in a manner that achieves profitability goals; and how uncertainty has a critical impact on MA functionality. Second, the differing dimensions and implications of uncertainty are distinguished. The principal distinction is between external and internal uncertainty. External uncertainties arise from unanticipated changes from customers, suppliers and the market and thus affect the predictability of the future on which plans and targets are based. The data gathered during the course of this research suggests that external uncertainty tends to be typified by pockets of instability oscillating with periods of relative stability. Internal uncertainties occur in relation to management effectiveness, reporting validity and choice of appropriate accounting perspective (five are identified - Product, Customer, Throughout, Process, Financial Accounting). The external uncertainties magnify the impact of the internal uncertainties by potentially changing and thus de-stabilising the requirements of management, the validity of reporting and the appropriateness of the accounting perspective used. Third, Management Accounting Systems (MAS) respond to external uncertainties, and the aspirations of external financial stakeholders for increased profitability, by operating in two differing modes – the first is fixed/control (Fixed), the second is inform/flex (Flex). Fixed is the default mode and assumes conditions of relative certainty; the role is to control the achievement of agreed plans and targets. Flex is intermittently initiated when, signalled by feedback, the impact of external uncertainties or profit pressures trigger the need to change original plans and targets. Calculative analysis informs revised operational plans aimed at maintaining the achievement of profitability goals; targets are flexed to reflect the changes. The intent is to develop a revised position of relative stability in which the achievement of profitability plans and targets can be controlled via reverting back to Fixed. The process is therefore continual, but appears to be typified by an uneven series of oscillations between the two modes. Four, the Financial Accounting (FA) profitability measure, with the goal derived from external financial stakeholders, provides partial responses to the three internal uncertainties by introducing for each an element of certainty. For management effectiveness uncertainty, the profitability goal provides a relatively certain external referent which can be cascaded down the organisational structure, and against which performance can be evaluated. For reporting validity uncertainty, FA standards provide an authoritatively accepted definition of profitability, so that reported profitability is treated as if it were ‘true and fair’. For multiple accounting perspectives uncertainty, four perspectives (Product, Customer, Throughout, Process) make up a range of MA tools for developing actions to achieve target profitability levels, and the fifth (FA) provides the definition of profitability; all five are complementary and compatible as their differing aggregations are composed of the same underlying financial transactions. These responses, however, are only partial as the aspirations of external financial stakeholders are in themselves substantially self referential and liable to change, and the underlying uncertainty of FA reporting validity still exists, even if treated as if it does not. The study contributes to the further development of MA theory. It extends the Otley (1999) framework towards linking operations and profitability through parallel operational and financial spaces, and incorporating the central role of uncertainty. It adds to the debate in MA research on uncertainty by providing a classification of its dimensions, and its impact on triggering a requirement for differing MA modes. It highlights the central role of profitability in providing a stable certainty of purpose as a counterbalance to inherent internal and external uncertainties. It provides a clear identification of the differences and complementarities between MA and FA, FA defining the quantum of profitability achieved, MA facilitating the achievement of profitability goal. Finally the study inputs to a wide range of issues addressed by MA research which at their heart reflect the impact of uncertainty (Budgeting, Accounting Representation, Costing Perspectives). The study contributes to practice by proposing a set of ten tenets designed to provide guidelines for MAS development, implementation and evaluation. These are drawn from a cross sectional deconstruction of the four findings, viewed as a whole, aimed at identifying the specific factors that have direct implications for practice. The intent is that these tenets provide a bridge between theory and practice, based on the premise that, since MA theory was drawn from practice, the test of MA theory development is its applicability and relevance to practice.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Ionizing radiation, higher plants, and radioprotection: From acute high doses to chronic low doses

© 2018 Caplin and Willey. Understanding the effects of ionizing radiation (IR) on plants is important for environmental protection, for agriculture and horticulture, and for space science but plants have significant biological differences to the animals from which much relevant knowledge is derived. The effects of IR on plants are understood best at acute high doses because there have been; (a) controlled experiments in the field using point sources, (b) field studies in the immediate aftermath of nuclear accidents, and (c) controlled laboratory experiments. A compilation of studies of the effects of IR on plants reveals that although there are numerous field studies of the effects of chronic low doses on plants, there are few controlled experiments that used chronic low doses. Using the Bradford-Hill criteria widely used in epidemiological studies we suggest that a new phase of chronic low-level radiation research on plants is desirable if its effects are to be properly elucidated. We emphasize the plant biological contexts that should direct such research. We review previously reported effects from the molecular to community level and, using a plant stress biology context, discuss a variety of acute high-and chronic low-dose data against Derived Consideration Reference Levels (DCRLs) used for environmental protection. We suggest that chronic low-level IR can sometimes have effects at the molecular and cytogenetic level at DCRL dose rates (and perhaps below) but that there are unlikely to be environmentally significant effects at higher levels of biological organization. We conclude that, although current data meets only some of the Bradford-Hill criteria, current DCRLs for plants are very likely to be appropriate at biological scales relevant to environmental protection (and for which they were intended) but that research designed with an appropriate biological context and with more of the Bradford-Hill criteria in mind would strengthen this assertion. We note that the effects of IR have been investigated on only a small proportion of plant species and that research with a wider range of species might improve not only the understanding of the biological effects of radiation but also that of the response of plants to environmental stress

Strategies for blocking the fibrogenic actions of connective tissue growth factor (CCN2): From pharmacological inhibition in vitro to targeted siRNA therapy in vivo

Connective tissue growth factor (CCN2) is a major pro-fibrotic factor that frequently acts downstream of transforming growth factor beta (TGF-β)-mediated fibrogenic pathways. Much of our knowledge of CCN2 in fibrosis has come from studies in which its production or activity have been experimentally attenuated. These studies, performed both in vitro and in animal models, have demonstrated the utility of pharmacological inhibitors (e.g. tumor necrosis factor alpha (TNF-α), prostaglandins, peroxisome proliferator-activated receptor-gamma (PPAR-γ) agonists, statins, kinase inhibitors), neutralizing antibodies, antisense oligonucleotides, or small interfering RNA (siRNA) to probe the role of CCN2 in fibrogenic pathways. These investigations have allowed the mechanisms regulating CCN2 production to be more clearly defined, have shown that CCN2 is a rational anti-fibrotic target, and have established a framework for developing effective modalities of therapeutic intervention in vivo