2,567 research outputs found
Kalman-Takens filtering in the presence of dynamical noise
The use of data assimilation for the merging of observed data with dynamical
models is becoming standard in modern physics. If a parametric model is known,
methods such as Kalman filtering have been developed for this purpose. If no
model is known, a hybrid Kalman-Takens method has been recently introduced, in
order to exploit the advantages of optimal filtering in a nonparametric
setting. This procedure replaces the parametric model with dynamics
reconstructed from delay coordinates, while using the Kalman update formulation
to assimilate new observations. We find that this hybrid approach results in
comparable efficiency to parametric methods in identifying underlying dynamics,
even in the presence of dynamical noise. By combining the Kalman-Takens method
with an adaptive filtering procedure we are able to estimate the statistics of
the observational and dynamical noise. This solves a long standing problem of
separating dynamical and observational noise in time series data, which is
especially challenging when no dynamical model is specified
Philosophical foundations, social power and social work practice
The contemporary philosophical landscape, which affects the fields of philosophical endeavor and the ways power is framed, is described. The covert manner these influences effect social work practice is made more visible through the use of ethically oriented decision making patterns; Ways that authority and discretion are used and abused, and abusive decision-making, are described making them easier to recognize and mitigate. Knowledge of current and potential ways that social power operates provides social workers tools in promoting the goals of empowerment and uncovering and enhancing clients\u27 strengths; Finally, a public sphere within which a reflective social work practice could operate, using concepts generated by other members of a social science public, addressing the interplay of power and ethics, is delineated
Attitude of the early Christian apologists to Greek philosophy as exemplified in Irenaeus of Lyons, Tertullian of Carthage and Clement of Alexandria
The bask here set for us, namely, to ascertain the nature of the
encounter "between Christianity and Greek philosophy in the period
specified would be less difficult in itself if we came to its
consideration with our minds unhampered by the opinions which have been
given and the conclusions reached concerning it* We have mainly to
bear in mind that the individual Christian thinkers with whom we shall
have to deal lived through that period of transition in the development
of Christianity in which many things we regard as normative had been
neither formalized nor stamped with the seal of later orthodoxy.
The Creed which some of us repeat, for instance, while in process of
evolution, had not as yet been reduced to standard form.(^) Indeed,
those second and third century pioneers in the realms of Christian
thought express themselves occasionally in terms that would certainly
have startled and would not in all likelihood have been tolerated by
the later Fathers of the Church
Spatial Competition in Private Labels
Previous studies find that private labels increase retailers' bargaining power with manufacturers and allow retailers to price discriminate. We use a spatial discrete choice model to show that retailers also use store brands to create market power through store differentiation, but not as a means of building market share.Marketing,
How Does Advertising Affect Market Performance? The Case of Generic Advertising
The effect of advertising on market performance has been a long-standing debate. Advertising that increases the dispersion of consumersâ valuations for advertised goods raises the market power of firms, while advertising that decreases the dispersion of consumersâ valuations leads to narrower price-cost margins and superior performance in markets for advertised goods. Numerous challenges confound the empirical identification of advertising effects on market performance. This paper proposes a simple method that relies on the revealed preferences of firms participating in generic advertising programs. Generic advertising programs provide a unique window through which to observe advertising effects on market performance, because changes in the dispersion of consumersâ valuations systematically redistributes rents among firms according to observable characteristics on producer size. We examine producer attitudes towards generic advertising in the âBeef. Itâs Whatâs for Dinnerâ campaign of the U.S. Beef Checkoff program and find the likelihood a producer favors an expansion of the advertising program increases in operating scale. This finding is consistent with advertising effects that have led to a decrease in the dispersion of consumersâ valuations for beef products and a commensurate increase in market performance.Advertising, Oligopoly, Marketing, L1, M37,
OBESITY AND HYPERBOLIC DISCOUNTING: AN EXPERIMENTAL ANALYSIS
Behavioral economists maintain that addictions such as alcoholism, smoking and over-eating represent examples of present-bias in decision making that is fundamentally irrational. In this article, we develop a model of present bias and apparently hyperbolic discounting that is fully consistent with rational behavior. We construct an experiment to test our hypothesis and to determine whether discount rates differ for individuals who engage in behaviors that could endanger their health. Our results show that discount functions are quasi-hyperbolic in shape, and that obesity and drinking are positively related to the discount rate. Anti-obesity policy, therefore, would be best directed to informing individuals as to the long-term implications of short-term gratification, rather than taxing foods directly.addiction, discounting, experiments, hyperbolic, obesity, time-inconsistency, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Health Economics and Policy, C91, D12, D91, I18,
Obesity and Hyperbolic Discounting: An Experimental Analysis
Behavioral economists maintain that addictions such as alcoholism, smoking and over-eating represent examples of present-bias in decision making that is fundamentally irrational. In this article, we develop a model of present bias and apparently hyperbolic discounting that is fully consistent with rational behavior. We construct an experiment to test our hypothesis and to determine whether discount rates differ for individuals who engage in behaviors that could endanger their health. Our results show that discount functions are quasi-hyperbolic in shape, and that obesity and drinking are positively related to the discount rate. Anti-obesity policy, therefore, would be best directed to informing individuals as to the long-term implications of short-term gratification, rather than taxing foods directly.addiction, discounting, experiments, hyperbolic, obesity, time-inconsistency., Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Health Economics and Policy, Institutional and Behavioral Economics, C91, D12, D91, I18.,
Bicycle Infrastructure and Traffic Congestion: Evidence from DC\u27s Capital Bikeshare
This study explores the impact of bicycle-sharing infrastructure on urban transportation. We estimate a causal effect of the Capital Bikeshare on traffic congestion in the metropolitan Washington, D.C., area. We exploit a unique traffic dataset that is finely defined on a spatial and temporal scale. Our approach examines within-city commuting decisions as opposed to traffic patterns on major thruways. Empirical results suggest that the availability of a bikeshare reduces traffic congestion upwards of 4% within a neighborhood. In addition, we estimate heterogeneous treatment effects using panel quantile regression. Results indicate that the congestion-reducing impact of bikeshares is concentrated in highly congested areas
Water intoxication presenting as maternal and neonatal seizures: a case report.
Introduction
We present an unusual case of fitting in the mother and newborn child, and the challenges faced in the management of their hyponatraemia due to water intoxication.
Case presentation
A previously well 37-year-old, primigravid Caucasian woman presented with features mimicking eclampsia during labour. These included confusion, reduced consciousness and seizures but without a significant history of hypertension, proteinuria or other features of pre-eclampsia. Her serum sodium was noted to be low at 111 mmol/litre as was that of her newborn baby. She needed anti-convulsants with subsequent intubation to stop the fitting and was commenced on a hypertonic saline infusion with frequent monitoring of serum sodium. There is a risk of long-term neurological damage from central pontine myelinolysis if the hyponatraemia is corrected too rapidly. Mother and baby went on to make a full recovery without any long-term neurological complications.
Conclusion
There is little consensus on the treatment of life-threatening hyponatraemia. Previous articles have outlined several possible management strategies as well as their risks. After literature review, an increase in serum sodium concentration of no more than 8â10 mmol/litre in 24 hours is felt to be safe but can be exceeded with extreme caution if life-threatening symptoms do not resolve. Formulae exist to calculate the amount of sodium needed and how much hypertonic intravenous fluid will be required to allow safer correction. We hypothesise the possible causes of hyponatraemia in this patient and underline its similarity in symptom presentation to eclampsia
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