The Paradox of Precaution

In the United States and most industrialized countries, regulatory policies and decision-making pertaining to food safety, occupational health and environmental protection are science-based. The actual pace and complexity of technological innovation, however, make it increasingly necessary to deal with situations where science cannot yet provide a definite picture. In this context, a now widely invoked rule, known as the 'Precautionary Principle', recommends to 'err on the side of preservation' until better scientific information becomes available. We draw a formal representation of this statement, and we show that it exhibits a logical contradiction. This negative result conveys a clarification of the type of actions science-based regulation should consider in the presence of scientific uncertainty. Aux États-Unis et dans la plupart des pays industrialisés, les règlements et politiques publics relatifs à la sécurité alimentaire, la santé au travail et la protection de l'environnement sont en principe basés sur l'information émanant des scientifiques. L'accélération et la complexité du progrès technologique rendent toutefois inévitable pour le régulateur de devoir prendre des décisions avant que la science puisse fournir une représentation claire du risque. Dans ce contexte, l'approche dite du «Principe de précaution» recommande d'«errer du côté de la prévention» jusqu'à ce que les scientifiques puissent donner le ton juste. Nous produisons une représentation formelle de ce principe, et nous montrons qu'il contient une incohérence logique. Ce résultat négatif permet néanmoins de préciser le type d'actions que la réglementation des risques basée sur la science devrait promouvoir en présence d'incertitude scientifique.Environmental and health risks; science-based regulation; scientific uncertainty; Precautionary Principle, Risques à la santé humaine et à l'environnement, réglementation basée sur la science, incertitude scientifique, principe de précaution

Assessing contaminated land cleanup costs and strategies

The remediation of contaminated sites is often subject to substantial cost overruns. This persistent discrepancy between estimated and realized costs is chiefly responsible for misguided land use and wasteful delays in the reconversion of former industrial sites. In order to deal with incomplete information and uncertainty in this context, this paper draws on stochastic modeling and mathematical finance methods. We show that relatively simple and usable formulas can then be derived for better assessing cleanup strategies. These formulas apply to generic remediation technologies and scenarios. They are robust to misspecification of key parameters (like the effectiveness of a prescribed treatment). They also yield practical rules for decision making and budget provisioning

Bacteriology of larval turbot development

The gut of newly-hatched turbot larvae contained very few bacteria but was rapidly colonised once feeding commenced and was generally dominated by Vibrio species. The source of the larval gut flora was the rotifers used as food, rather than the ambient water. In extensive-rearing systems the larval turbot gut was colonised more slowly than in intensive-rearing systems and this was correlated with better growth and survival rates. A wide variety of bacteria were represented in the gut flora of turbot larvae but recognised pathogens were rarely found and their presence was not correlated with low survival rates. Scanning electron microscopy revealed that the bacterial flora of rotifers was almost entirely associated with the surface of the rotifers; approximately 65% of bacteria were removed by rinsing rotifers in sterile seawater and only 5% remained after treatment with benzalkonium chloride. Attempts to reduce the viable bacterial load of rotifers with detergents and other antibacterial compounds were unsuccessful, as all the substances tested were either toxic to rotifers, or were ineffective at reducing the number of rotifer-associated bacteria. Exposure to lysozyme at 0.2% salinity resulted in >70% reduction in the bacterial load of rotifers and lysozyme-treated rotifers were palatable to turbot larvae. However, the osmotic shock due to the low salinity caused the rotifers to stop swimming and sink to the bottom of the larval-rearing tanks. Although the rotifers recovered overnight, their guts were empty, thus, they were probably of little nutritional value to the turbot larvae. Ultra-violet irradiation of rotifers was more successful. Large numbers of rotifers were treated by passing the culture through a water jacket surrounding a U.V. tube lamp. A >99% reduction of the bacterial load of unenriched rotifers was obtained at a flow rate of 1.5 litres per min and a concentration of 200 rotifers per ml. This decreased to a >96% reduction if the rotifers were enriched with algae prior to treatment. U.V.-treated rotifers were palatable to turbot larvae and in field trials at Golden Sea Produce, Hunterston, the gut of larvae fed with U.V.-treated rotifers was colonised more slowly than in controls fed untreated rotifers. In two field trials with extensively-reared turbot larvae, the survival rates of the larvae fed with U.V.-treated rotifers were higher than those of larvae fed untreated rotifers. The gut microflora of intensively-reared turbot larvae fed with U.V.-treated rotifers was diverse and resembled that of unfed larvae, whereas the gut microflora of larvae fed untreated rotifers was dominated by a few Vibrio species. The use of rotifers as carriers was considered a potentially effective means of introducing a probiotic bacterial flora into the gut of turbot larvae. Axenically cultured rotifers were rapidly colonised when the culture water was inoculated with defined bacteria. Within two hours, approximately 250 bacteria adhered per rotifer, or were ingested by rotifers, with each of the five bacterial species tested. Attempts were made to colonise rotifers subsequently fed to larval turbot, with a strain of Vibrio alginolyticus isolated from healthy, intensively-reared larvae. However, the bacteria either lost viability or did not stably colonise the gut of turbot larvae

Economic Policy when Models Disagree

This paper proposes a general way to craft public policy when there is no consensual account of the situation of interest. The design builds on a dual extension of the traditional theory of economic policy. It does not require a representative policymaker’s utility function (as in the literature on ambiguity), a reference model (as in robust control theory) or some prior probability distribution over the set of supplied scenarios (as in the Bayesian model-averaging approach). The obtained policies are shown to be robust and simple in a precise and intuitive sense. Ce texte propose une nouvelle approche du design des politiques publiques, quand il n'y pas de consensus entre experts sur une représentation adéquate de la situation. Techniquement parlant, nous adoptons pour ce faire une version généralisée de la théorie traditionnelle de la politique économique, telle que développée il y a plusieurs décennies par Jan Tinbergen. Contrairement aux solutions existantes à l'incertitude sur les modèles, notre approche ne demande pas de connaître la fonction d'utilité des décideurs politiques (à l'inverse de la littérature sur l'ambigüité), ni d'avoir un modèle de référence (par contraste avec la théorie du contrôle robuste), ni de posséder une distribution de probabilité sur l'ensemble des scénarios proposés (a contrario de l'approche bayesienne). Nous montrons que les politiques obtenues possèdent plusieurs propriétés que la littérature souvent postule a priori, comme la robustesse et la simplicité.Model uncertainty, Theory of economic policy, Ambiguity, Robustness, Incertitude sur les modèles, théorie de la politique économique, ambigüité, robustesse

Transient, unsettling and creative space: Experiences of liminality through the accounts of Chinese students on a UK-based MBA

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ The Author(s) 2009.This article explores the experiences of liminality through the accounts of Chinese students on a UK-based MBA programme. The transient nature of the MBA experience, as well as the international status of the Chinese student, is resonant with conceptualizations of liminality as ‘in between’ space. Based on semi-structured interviews with 20 MBA graduates who had subsequently returned to China with their qualification, we explored their perceptions of outcomes from the course and their experiences as international students on a programme imbued with western norms and values. Results support the unsettling yet creative implications of liminality, as well as the fragmented insecure nature of identities, as individuals pass through the MBA ‘rite of passage’ in terms of ‘becoming’ a manager and entering a new phase of career. Accounts suggest the creation of hierarchical structures within liminal space whereby Chinese students, through their positioning at the margin, have uncomfortable yet illuminating encounters with alterity. At the same time, they experience levels of ambiguity and uncertainty in the post-liminal phase of China-located employments, as new western-based managerial identities collide with dominant discourses of Chinese organization

Aging-like Phenotype and Defective Lineage Specification in SIRT1-Deleted Hematopoietic Stem and Progenitor Cells

Summary Aging hematopoietic stem cells (HSCs) exhibit defective lineage specification that is thought to be central to increased incidence of myeloid malignancies and compromised immune competence in the elderly. Mechanisms underlying these age-related defects remain largely unknown. We show that the deacetylase Sirtuin (SIRT)1 is required for homeostatic HSC maintenance. Differentiation of young SIRT1-deleted HSCs is skewed toward myeloid lineage associated with a significant decline in the lymphoid compartment, anemia, and altered expression of associated genes. Combined with HSC accumulation of damaged DNA and expression patterns of age-linked molecules, these have striking overlaps with aged HSCs. We further show that SIRT1 controls HSC homeostasis via the longevity transcription factor FOXO3. These findings suggest that SIRT1 is essential for HSC homeostasis and lineage specification. They also indicate that SIRT1 might contribute to delaying HSC aging

Polycystic Ovary Syndrome: A Brain Disorder Characterized by Eating Problems Originating during Puberty and Adolescence

Polycystic ovary syndrome (PCOS) is an endocrine condition associated with reproductive and psychiatric disorders, and with obesity. Eating disorders, such as bulimia and recurrent dieting, are also linked to PCOS. They can lead to the epigenetic dysregulation of the hypothalamic–pituitary–gonadal (HPG) axis, thereby impacting on ovarian folliculogenesis. We postulate that PCOS is induced by psychological distress and episodes of overeating and/or dieting during puberty and adolescence, when body dissatisfaction and emotional distress are often present. We propose that upregulated activation of the central HPG axis during this period can be epigenetically altered by psychological stressors and by bulimia/recurrent dieting, which are common during adolescence and which can lead to PCOS. This hypothesis is based on events that occur during a largely neglected stage of female reproductive development. To date, most research into the origins of PCOS has focused on the prenatal induction of this disorder, particularly in utero androgenization and the role of anti-Müllerian hormone. Establishing causality in our peripubertal model requires prospective cohort studies from infancy. Mechanistic studies should consider the role of the gut microbiota in addition to the epigenetic regulation of (neuro) hormones. Finally, clinicians should consider the importanc

Are you Ready? Assessing Whether Organisations are Prepared for Digital Preservation

In early 2009 the Planets project undertook a survey of national libraries, archives, and other content-holding organisations in Europe to better understand the organisations' digital preservation activities and needs, and to ensure that Planets' technology and services are designed to meet them. Over 200 responses were received including a cross-section of major libraries and archives especially in Europe. The results provide a snapshot of organisations' readiness to preserve digital collections for the future. The survey revealed a high level of awareness of the challenges of digital preservation within organisations. Findings indicated that approximately half of those organisations surveyed have taken measures to develop digital preservation policies and to budget for it, while a majority have incorporated digital preservation into their organisational planning. Organisations predict that within a decade they will need to store large quantities of data in a wide range of formats from a variety of sources; three quarters of them are looking to invest in a solution within the next two years. However, the findings also point to varying degrees of readiness. Organisations with a digital preservation policy are significantly further advanced in their work to preserve digital collections for the long-term than others