Numerical modelling of mesoscale atmospheric dispersion

Fall 1992.Includes bibliographical references

Improving the Accuracy of UK Regulatory Cost Estimates

UK Government departments are required to undertake a Regulatory Impact Assessment (RIA) when introducing any policy change that places a burden on businesses, charities, the voluntary sector or individuals. Part of this assessment involves the appraisal of the costs (and benefits) associated with complying with all the available options, as well as the wider economic costs. Recent evidence has suggested that the compliance costs, when assessed ex post, tend to be lower than the ex ante assessment made beforehand (see e.g. Harrington et al 1999). Accurate cost estimates are important as errors can lead to under or over regulation. This, in turn, can result in growth and innovation being hindered or, in the case of under regulation, growth being achieved at the expense of the natural resource base (including human health and well being). In order to shed more light on the validity of RIA cost estimates and identify ways of improving their accuracy, Defra decided to commission a study comparing the ex ante and ex post costs of complying with regulatory changes. A total of eight case studies were carried out for this study, covering a range of recent environmental, agricultural and food-related regulations in the UK. Preliminary findings of this study indicate that while ex ante costs are often overestimated, there can also be significant underestimates. Reasons for errors in cost estimation are discussed and strategies for improving their accuracy suggested.Public Economics,

Criticality of natural absorbing states

We study a recently introduced ladder model which undergoes a transition between an active and an infinitely degenerate absorbing phase. In some cases the critical behaviour of the model is the same as that of the branching annihilating random walk with $N\geq 2$ species both with and without hard-core interaction. We show that certain static characteristics of the so-called natural absorbing states develop power law singularities which signal the approach of the critical point. These results are also explained using random walk arguments. In addition to that we show that when dynamics of our model is considered as a minimum finding procedure, it has the best efficiency very close to the critical point.Comment: 6 page

Metabolic balance studies and dietary protein requirements in patients undergoing continuous ambulatory peritoneal dialysis

Metabolic balance studies and dietary protein requirements in patients undergoing continuous ambulatory peritoneal dialysis. Balance studies for nitrogen, potassium, magnesium, phosphorus, and calcium were carried out in eight men undergoing continuous ambulatory peritoneal dialysis (CAPD) to determine dietary protein requirements and mineral balances. Patients were fed high energy diets for 14 to 33 days which provided either 0.98 (seven studies) or 1.44g (six studies) of primarily high biological value protein/kg body wt/day. Mean nitrogen balance was neutral with the lower protein diet (+0.35 ± 0.83SEMg/day) and strongly positive with the higher protein diet (+2.94 ± 0.54g/day). With the higher protein diet the balances for potassium, magnesium, and phosphorus were strikingly positive, there was an increase in body weight in all patients, and a rise in mid-arm muscle circumference in five of the six patients. The relation between protein intake and nitrogen balance suggests that the daily protein requirement for clinically stable CAPD patients should be at least 1.1g/kg/day; to account for variability among subjects 1.2 to 1.3g protein/kg/day is probably preferable. Potassium balance correlated directly with nitrogen balance (r = 0.81). High fecal potassium losses (19 ± 1.2 mEq/day) in all patients probably helped maintain normal serum potassium concentrations. Mean serum magnesium was increased (3.1 ± 0.1 mg/dl), and magnesium balances were positive suggesting that the dialysate magnesium of 1.85 mg/dl is excessive. The netgain of calcium from dialysate was 84 ± 18 mg/day; this correlated inversely with serum calcium levels (r = -0.90).Bilans métaboliques et besoins protéiques alimentaires de malades en dialyse péritonéale continue ambulatoire. Des études de bilan de l'azote, du potassium, du magnésium, du phosphore et du calcium, étaient fait en sept hommes en dialyse péritonéale continue ambulatoire (CAPD), pour déterminer leurs besoins protéiques alimentaires et leur bilan minéral. Les malades ont reçu pendant 14 à 33 jours des régimes hautement énergétiques, apportant soit 0,98 (sept études), soit 1,44g (six études) de protéines de haute valeur biologique par kg de poids et par jour. Le bilan azoté moyen etait nul avec le régime comportant la plus faibie teneur protéique (+ 0,35 ± 0,88g/jSEM) et était fortement positive avec le régime à plus forte teneur protéique (+2,94 ± 0,54g/j). Avec le régime à haute teneur en protéine, les bilans potassique, magnésien et phosphoré étaient fortement positifs; le poids corporel s'est élevé chez tous les malades; la circonférence musculaire mesurée du milieu du bras a augmenté chez cinq sur six malades. La relation existant entre l'apport protéique et le bilan azoté suggère que les besoins journaliers en protéines pour des malades cliniquement stables en CAPD devraient être au moins de 1,1g/kg/j; 1,2 à 1,3g de protéines/kg/j sont sans doute préférables pour tenir compte de la variabilité entre les sujets. Le bilan potassique était directement corrélé avec la balance azotée (r = 0,81). De fortes pertes potassiques fécales (19 ± 1,2 mEq/j) chez tous les malades ont probablement contribué à maintenir normales les concentrations sériques du potassium. La magnésémie moyenne était élevée (3,1 ± 0,1 mg/dl), et les bilans magnésiens aient positifs suggérant que le magnésium du dialysat (1,85 18 mg/dl) était trop élevé. Le gain net en calcium à partir du dialysat était de 84 ± 18 mg/j; ce gain était inversement corrélé avec la calcémie (r = 0,90)

Extremality of Gaussian quantum states

We investigate Gaussian quantum states in view of their exceptional role within the space of all continuous variables states. A general method for deriving extremality results is provided and applied to entanglement measures, secret key distillation and the classical capacity of Bosonic quantum channels. We prove that for every given covariance matrix the distillable secret key rate and the entanglement, if measured appropriately, are minimized by Gaussian states. This result leads to a clearer picture of the validity of frequently made Gaussian approximations. Moreover, it implies that Gaussian encodings are optimal for the transmission of classical information through Bosonic channels, if the capacity is additive.Comment: 4 page

Interactions Between Transient and Sustained Neural Signals Support the Generation and Regulation of Anxious Emotion

Anxious emotion can manifest on brief (threat response) and/or persistent (chronic apprehension and arousal) timescales, and prior work has suggested that these signals are supported by separable neural circuitries. This fMRI study utilized a mixed block-event–related emotional provocation paradigm in 55 healthy participants to simultaneously measure brief and persistent anxious emotional responses, testing the specificity of, and interactions between, these potentially distinct systems. Results indicated that components of emotional processing networks were uniquely sensitive to transient and sustained anxious emotion. Whereas the amygdala and midbrain showed only transient responses, the ventral basal forebrain and anterior insula showed sustained activity during extended emotional contexts that tracked positively with task-evoked anxiety. States of lesser anxiety were associated with greater sustained activity in the ventromedial prefrontal cortex. Furthermore, ventromedial prefrontal recruitment was lower in individuals with higher scores on intolerance of uncertainty measures, and this hyporecruitment predicted greater transient amygdala responding to potential threat cues. This work demonstrates how brain circuitries interact across temporal scales to support brief and persistent anxious emotion and suggests potentially divergent mechanisms of dysregulation in clinical syndromes marked by brief versus persistent symptoms of anxiety.Psycholog

Glucose absorption during continuous ambulatory peritoneal dialysis

Glucose absorption during continuous ambulatory peritoneal dialysis. Patients undergoing continuous ambulatory peritoneal dialysis (CAPD) are exposed to a continuous infusion of glucose via their peritoneal cavity. We performed studies to quantitate the amount of energy derived from dialysate glucose. Net glucose absorption averaged 182 ± (SD) 61 g/day in 19 studies with a dialysate dextrose concentration of 1.5 or 4.25 g/dl. The amount of glucose absorbed per liter of dialysate (y) varied with the concentration of glucose in dialysate (x), (y = 11.3x - 10.9, r = 0.96), The amount of glucose absorbed per day during a given dialysis regimen was constant. Energy intake from dialysate glucose was 8.4 ± 2.8 kcal/kg of body wt per day, or 12 to 34% of total energy intake. This additional energy may contribute to the anabolic effect reported during CAPD. The ability to vary glucose absorption by altering the dialysate glucose concentration may prove a useful tool to modify energy intake.Absorption de glucose au cours de la dialyse péritonéale continue ambulatoire. Les malades soumis à la dialyse péritonéale continue ambulatoire (CAPD) sont exposés à une administration continue de glucose via leur cavité péritonéale. La quantité d'énergie qui dérive du glucose du dialysat a été quantifiée. L'absorption nette de glucose est en moyenne de 182 ± (SD) 61 g/jour au cours de 19 études avec un dialysat contenant du dextrose, 1,5 ou 4,25 g/dl. La quantité de glucose absorbée par litre de dialysat (y) varie avec la concentration de glucose dans le dialysat (x), (y = 11,3x - 10,9, r = 0,96). La quantité de glucose absorbée par jour pour un type donné de dialyse a été constante. L'entrée d'énergie à partir du glucose du dialysat était de 8,4 ± 2,8 kcal/kg de poids par jour, soit 12 à 34% de l'entrée totale d'énergie. Cette énergie supplémentaire peut contribuer à l'effet anabolique rapporté au cours de CAPD. La possibilité de faire varier l'absorption de glucose en modifiant la concentration de glucose dans le dialysat peut être un moyen utile pour influencer l'entrée d'énergie

Technology Transfer and Innovation Policy at Canadian Universities: Opportunities and Social Costs

This report, supported by a Social Sciences and Humanities Research Council (SSHRC) Knowledge Synthesis Grant, critically examines the role of universities in transmitting knowledge in the forms of technology transfer mechanisms, intellectual property agreements and other knowledge diffusion policies. In reviewing and synthesizing the recent literature on the topic, we seek to provide some initial evidence-based policy recommendations in order to generally strengthen Canada‘s innovation ecosystem and more specifically to maximize the return on the nation‘s investment in higher education research and development

Numerical simulation of micromachined acoustic resonators

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76479/1/AIAA-2000-546-400.pd