Influence of Subslab Aggregate Permeability of SSV Performance

The effectiveness of the technique of subslab ventilation (SSV) for limiting radon entry into basements was investigated through complementary experimentation and numerical modeling. Determination of the impact of subslab aggregate permeability on SSV performance was a primary objective. Subslab pressure fields resulting from SSV were measured in six well-characterized basements, each with a different combination of soil and aggregate permeability. The relationship between air velocity and pressure gradient within the three types of aggregate installed beneath the basement slabs was measured in the laboratory. A new numerical model of SSV was developed and verified with the field data. This model simulates non-Darcy flow in the aggregate. We demonstrate that non-Darcy effects significantly impact SSV performance. Field data and numerical simulations indicate that increasing the aggregate permeability within the investigated range of 2 x 10{sup -8} m{sup 2} to 3 x 10{sup -7} m{sup 2} substantially improves the extension of the subslab pressure field due to SSV operation. Subslab pressure field extension also improves as soil permeability decreases between 10{sup -9} m{sup 2} and 10{sup -10} m{sup 2}. With a slab-wall gap thickness of 1 mm and the range of aggregate permeability investigated, further reductions in soil permeability do not significantly improve the subslab pressure field extension. Sealing of cracks in the slab and excavation of a small pit where the SSV pipe penetrates the slab also dramatically improve this pressure field extension. A large ratio of aggregate permeability to soil permeability reduces the need for large depressurizations at the SSV pit. Our findings are consistent with the results of prior field studies; however, our understanding of SSV is improved and the dependence of SSV performance on the relevant parameters can now be quantified with the model

Impacts of a Sub-Slab Aggregate Layer and a Sub-Aggregate Membrane on Radon Entry Rate: A Numerical Study

A subslab aggregate layer can increase the radon entry rate into a building by up to a factor of 5. We use a previously tested numerical technique to investigate and confirm this phenomenon. Then we demonstrate that a sub-aggregate membrane has the potential to significantly reduce the increase in radon entry rate due to the aggregate layer, even when a gap exists between the perimeter of the membrane and the footer. Such membranes greatly reduce diffusion of radon from the soil into the aggregate and are impermeable to flow. Radon entry through the basement floor slab is limited to radon entry through the holes in the membrane. In addition, a sub-aggregate membrane is predicted to improve the performance of active sub-slab ventilation systems and makes passive systems more promising

Tissue Doppler imaging of carotid plaque wall motion: a pilot study

BACKGROUND: Studies suggest the physical and mechanical properties of vessel walls and plaque may be of clinical value in the diagnosis and treatment of cardiovascular atherosclerotic disease. The purpose of this pilot study was to investigate the potential clinical application of ultrasound Tissue Doppler Imaging (TDI) of Arterial Wall Motion (AWM) and to quantify simple wall motion indices in normal and diseased carotid arteries. METHODS: 224 normal and diseased carotid arteries (0–100% stenoses) were imaged in 126 patients (age 25–88 years, mean 68 ± 11). Longitudinal sections of the carotid bifurcation were imaged using a Philips HDI5000 scanner and L12-5 probe under optimized TDI settings. Temporal and spatial AWMs were analyzed to evaluate the vessel wall displacements and spatial gradients at peak systole averaged over 5 cardiac cycles. RESULTS: AWM data were successfully extracted in 91% of cases. Within the carotid bifurcation/plaque region, the maximum wall dilation at peak systole ranged from -100 to 750 microns, mean 335 ± 138 microns. Maximum wall dilation spatial gradients ranged 0–0.49, mean 0.14 ± 0.08. The AWM parameters showed a wide variation and had poor correlation with stenoses severity. Case studies illustrated a variety of pertinent qualitative and quantitative wall motion features related to the biophysics of arterial disease. CONCLUSION: Our clinical experience, using a challenging but realistic imaging protocol, suggests the use of simple quantitative AWM measures may have limitations due to high variability. Despite this, pertinent features of AWM in normal and diseased arteries demonstrate the potential clinical benefit of the biomechanical information provided by TDI

KD5170, a novel mercaptoketone-based histone deacetylase inhibitor that exhibits broad spectrum antitumor activity in vitro and in vivo

Abstract Histone deacetylase (HDAC) inhibitors have garnered significant attention as cancer drugs. These therapeutic agents have recently been clinically validated with the market approval of vorinostat (SAHA, Zolinza) for treatment of cutaneous T-cell lymphoma. Like vorinostat, most of the small-molecule HDAC inhibitors in clinical development are hydroxamic acids, whose inhibitory activity stems from their ability to coordinate the catalytic Zn 2+ in the active site of HDACs. We sought to identify novel, nonhydroxamate-based HDAC inhibitors with potentially distinct pharmaceutical properties via an ultra-high throughput small molecule biochemical screen against the HDAC activity in a HeLa cell nuclear extract. An A-mercaptoketone series was identified and chemically optimized. The lead compound, KD5170, exhibits HDAC inhibitory activity with an IC 50 of 0.045 Mmol/L in the screening biochemical assay and an EC 50 of 0.025 Mmol/L in HeLa cell -based assays that monitor histone H3 acetylation. KD5170 also exhibits broad spectrum classe

Testing the cultural theory of risk in France

Cultural Theory, as developed by Mary Douglas, argues that differing risk perceptions can be explained by reference to four distinct cultural biases: hierarchy, egalitarianism, individualism, and fatalism. This paper presents empirical results from a quantitative survey based on a questionnaire devised by Karl Dake to measure these cultural biases. A large representative sample (N = 1022) was used to test this instrument in the French social context. Correlations between cultural biases and perceptions of 20 social and environmental risks were examined. These correlations were very weak, but were statistically significant: cultural biases explained 6%, at most, of the variance in risk perceptions. Standard sociodemographic variables were also weakly related to risk perceptions (especially gender, social class, and education), and cultural biases and sociodemographic variables were themselves inter correlated (especially with age, social class, and political outlook). The authors compare these results with surveys conducted in other countries using the same instrument and conclude that new methods, more qualitative and contextual, still need to be developed to investigate the cultural dimensions of risk perceptions. The paper also discusses relationships between perceptions of personal and residual risk, and between perceived risk and demand for additional safety measures. These three dimensions were generally closely related, but interesting differences were observed for some risk issues.</p

Perception des risques nucléaires

La perception d'un risque par l'individu dépend de nombreux facteurs, certains propres à l'individu (psychologie, connaissance, expérience), d'autres descriptifs du contexte sociétal (culture, idéologie), d'autres enfin relatifs à la nature du risque. Le mot risque possède des sens divers et il est appréhendé de façon différente par les trois catégories d'intervenants impliqués dans la maîtrise du risque, à savoir les techniciens, les gestionnaires et les individus du public Plusieurs modèles pour décrire comment s'élabore la perception sont présentés. Les dimensions intervenant dans la perception sont énumérées et une classification des divers risques est proposée. A partir d'enquêtes faites au sein du public, la perception du risque nucléaire est située par rapport à celle d'autres risques. Enfin, des résultats sont donnés concernant la confiance dans l'information diffusée et la crédibilité des organismes et institutions

Welfare barriers and levers for improvement in organic and low-input outdoor pig and poultry farmsinvited

Session 62, Theatre 1International audienceThe PPILOW project aims to co-construct innovations to improve Poultry and Pig Welfare in Low-input outdoorand Organic farming systems through a multi-actor approach. Its first step was to sum up animal welfare challengesobserved in these systems and levers of improvement, from a review of literature data and research projects. Data werecompleted with information from key informants of the supply chains of poultry meat, eggs and pork in Italy, France,the United Kingdom and Finland. The interviews indicated that the main issues in poultry were: feeding, biosecurity,lack of range use and range management, feather pecking, weather, regulation, flock size or density, predation, bonefractures, lack of robustness, parasitism, pododermatitis, arthrosis, nervousness, water quality, catching and time spentby farmers. The main issues in pig were: feeding, tail biting, mortality, weather, predation, lack of robustness, lackof range use, castration, animal aggressiveness and competition, water quality, range management, human welfare,biosecurity issues, flock size or density, parasitism, insolation burns, joint abnormalities, parturition in freedom andpollution. This information has implemented a participatory approach for proposing welfare-improvement levers. Someissues and potential solutions were included in PPILOW experiments (phytotherapy against parasitism, involvementof animal personality in range use, rearing of entire pig males, genetic selection for reduced piglet mortality, improvedfarrowing huts for sows and piglets reared on range, avoiding feather pecking in laying hens with intact beaks, avoidingthe killing of day-old male chicks, etc.), and solution costs evaluated. The results will provide a combination of practicalsolutions for welfare improvement in Europe. The PPILOW project has received funding from the European Union’sHorizon 2020 Research and Innovation Programme under grant agreement N°816172