The Economics of Density: Evidence From the Berlin Wall

This paper develops a quantitative model of internal city structure that features agglomeration and dispersion forces and an arbitrary number of heterogeneous city blocks. The model remains tractable and amenable to empirical analysis because of stochastic shocks to commuting decisions, which yield a gravity equation for commuting flows. To structurally estimate agglomeration and dispersion forces, we use data on thousands of city blocks in Berlin for 1936, 1986, and 2006 and exogenous variation from the city's division and reunification. We estimate substantial and highly localized production and residential externalities. We show that the model with the estimated agglomeration parameters can account both qualitatively and quantitatively for the observed changes in city structure. We show how our quantitative framework can be used to undertake counterfactuals for changes in the organization of economic activity within cities in response, for example, to changes in the transport network.     

Multivariate Bayes Wavelet shrinkage and applications

In recent years, wavelet shrinkage has become a very appealing method for data de-noising and density function estimation. In particular, Bayesian modelling via hierarchical priors has introduced novel approaches for Wavelet analysis that had become very popular, and are very competitive with standard hard or soft thresholding rules. In this sense, this paper proposes a hierarchical prior that is elicited on the model parameters describing the wavelet coefficients after applying a Discrete Wavelet Transformation (DWT). In difference to other approaches, the prior proposes a multivariate Normal distribution with a covariance matrix that allows for correlations among Wavelet coefficients corresponding to the same level of detail. In addition, an extra scale parameter is incorporated that permits an additional shrinkage level over the coefficients. The posterior distribution for this shrinkage procedure is not available in closed form but it is easily sampled through Markov chain Monte Carlo (MCMC) methods. Applications on a set of test signals and two noisy signals are presented.     

Bayesian acceptance sampling plans following economic criteria: An application to paper pulp manufacturing

The main purposes of this paper are to derive Bayesian acceptance sampling plans regarding the number of defects per unit of product, and to illustrate how to apply the methodology to the paper pulp industry. The sampling plans are obtained following an economic criterion: minimize the expected total cost of quality. It has been assumed that the number of defects per unit of product follows a Poisson distribution with process average 5 , whose prior information is described either for a gamma or for a non- informative distribution. The expected total cost of quality is composed of three independent components: inspection, acceptance and rejection. Both quadratic and step-loss functions have been used to quantify the cost incurred for the acceptance of a lot containing units with defects. Combining the prior information on 5 with the loss functions, four different sampling plans are obtained. When the quadratic-loss function is used, an analytical relation between the optimum settings of the sample size and the acceptance number is derived. The robustness analysis indicates that the sampling plans obtained are robust with respect to the prior distribution of the process average as well as to the misspecification of its mean and variance.     

The Effect of Absorptive Capacity on Innovativeness: Context and Information Systems Capability as Catalysts

The purpose of this study is to examine the relationship between absorptive capacity and company innovativeness and to identify potential contexts and capabilities that can act as catalysts for these relationships. We also examine the relationship between absorptive capacity and the existence and enhancement of innovativeness. These relationships are examined through an empirical investigation of 286 large Spanish companies. Our results show that absorptive capacity is an important dynamic determinant for developing a company's innovativeness. Moreover, this relationship is best explained by two related constructs. First, the company's unlearning context is a crucial determinant for both potential capacity and realized absorptive capacity. Second, the results also indicate a tangible means for managers to enhance their absorptive capacity through information systems capabilities.     

A note on simultaneous inference with rerandomization tests

Valid simultaneous confidence intervals based on rerandomization are provided for the first time. They are derived from joint confidence regions which are constructed by testing for all possible parametric values. A simple exampe illustrates these confidence intervals and compares inferences from them with other methods.     

<Emphasis Type="Italic">Si,Se Puede</Emphasis>: Organizing Latino Immigrant Workers in South Omaha’s Meatpacking Industry

Faced with declining union membership and a growing immigrant workforce, the US labor movement has started to realize the importance of organizing immigrant workers. Yet the conventional wisdom among many within the movement is that immigrant workers are “unorganizable.” Based on a case study of a collaborative effort between the United Food and Commercial Workers Union and Omaha Together, One Community to organize an estimated 4,000 Latino immigrant meatpacking workers, I demonstrate not only the “organizability” of immigrant workers, but also the fact that they have been organizing themselves, with the help of a community-based organization, in the absence of union efforts. This case study suggests that in order to facilitate successful organizing campaigns among immigrant workers, unions need to reach out to community-based organizations and institutions that have established relationships with immigrant workers.

Resolving Zeckhauser’s paradox

Theory and Decision - Zeckhauser’s paradox has puzzled and entertained many rationality enthusiasts for almost half a century. You are forced to play a Russian Roulette with a 6-chamber...     

Topiramate Combined with Cognitive Restructuring for the Treatment of Gambling Disorder: A Two-Center,Randomized, Double-Blind Clinical Trial

Gambling disorder (GD) is a prevalent condition for which no pharmacological treatment has yet been approved, although there is evidence that topiramate can reduce impulsivity in GD and craving in various addictive behaviors. The goal of this study was to investigate the effectiveness of topiramate combined with cognitive restructuring for GD in a two-center, randomized, double-blind clinical trial. Participants were individuals seeking outpatient treatment for GD (n = 30), treated with either topiramate or placebo combined with a brief cognitive intervention, over a 12-week period, the dose of topiramate being tapered up during the first 8 weeks. The main outcome measures were gambling craving, behavior, and cognitive distortions; impulsivity; depression and social adjustment. Topiramate proved superior to placebo in reducing gambling craving (P = 0.017); time and money spent gambling (P = 0.007 and P = 0.047, respectively); cognitive distortions related to gambling (P = 0.003); and social adjustment (P = 0.040). We found no significant effects on impulsivity or depression. These findings are in contrast with data from a previous clinical trial with topiramate for GD. In the current study, we found that topiramate affects features specifically related to gambling addiction and had no significant effect on associated phenomena such as impulsiveness and depression. We believe that this response could be due to synergistic interaction between topiramate and the cognitive intervention.     

Evaluation of hip abductor and adductor strength in the elderly: a reliability study

Background

In elderly individuals an increased muscle strength contributes to the diminution of the falls risk and associated adverse events. An increasing interest in lateral control exists due to the fatal consequences of postero-lateral falls. Therefore a proper assessment of frontal plane hip muscle strength in elderly is important but remains challenging.Therefore we aimed to investigate the feasibility and repeatability of a hip abductor and adductor maximum voluntary isometric strength (MVIS) and rate of force generation (RFG) test in elderly. This represents an initial step in the development process of a new and clinically relevant test that could lead to more specific treatment protocols for this population.

Methods

In this measurement focused study hip abduction (ABD) and adduction (ADD) MVIS and RFG were tested twice within one to three hours with a dynamometer fixed to a custom made frame in a geriatric population including fallers and non-fallers. Intraclass correlation coefficient (ICC_agreement), standard error of measurement (SEM), and smallest detectable difference (SDD) were determined.

Results

All recruited persons (N?=?76; mean age (SD) 80.46 (7.05) years old) completed the tests. The average time needed to complete the strength tests was 10.58 min. (1.56) per muscle group. The reliability of the hip ABD and ADD was high with ICC’s_agreement ranging from 0.83 to 0.97. The SDD varied between 18.1 and 81.8% depending on the muscle group and type of strength that was evaluated.

Conclusion

Hip abductor and adductor strength measures in older person are feasible and reliable. However, the significance of moderate changes in these measurements may be limited by the large SDD and SEM. Therefore, physical therapist should be careful when using this measure for assessing the progress of an individual person in a daily clinical use.