Simple Wriggling is Hard unless You Are a Fat Hippo

We prove that it is NP-hard to decide whether two points in a polygonal domain with holes can be connected by a wire. This implies that finding any approximation to the shortest path for a long snake amidst polygonal obstacles is NP-hard. On the positive side, we show that snake's problem is "length-tractable": if the snake is "fat", i.e., its length/width ratio is small, the shortest path can be computed in polynomial time.Comment: A shorter version is to be presented at FUN 201

Jeeg: Temporal Constraints for the Synchronization of Concurrent Objects

We introduce Jeeg, a dialect of Java based on a declarative replacement of the synchronization mechanisms of Java that results in a complete decoupling of the 'business' and the 'synchronization' code of classes. Synchronization constraints in Jeeg are expressed in a linear temporal logic which allows to effectively limit the occurrence of the inheritance anomaly that commonly affects concurrent object oriented languages. Jeeg is inspired by the current trend in aspect oriented languages. In a Jeeg program the sequential and concurrent aspects of object behaviors are decoupled: specified separately by the programmer these are then weaved together by the Jeeg compiler

IT enabled service delivery innovation from quality perspective

[EN] The objective is to understand how information and service quality to influence of IT enabled service (ITeS), then to enhance service delivery innovation (SDI). This study bases ITeS to elaborate two research questions by adopting Rodosek’s business reference model. Consequently, we conduct a case study approach, by deriving proposals concerning the relationships among two quality perspectives, ITeS, and SDI in a Taiwanese publishing company. In the end, we concluded three related findings. Firstly, the company based on service orientated to provide basic service functions to encourage more users to enjoy their services, as well as facilitating collaborative work via the online discussion area. Secondly, the company adopted advanced service functions to extend their service scopes to end-users, such as download the news into handheld devices. Finally, the company utilized the supporting service functions to assist customers integrating the ideas and plans.Lin, Y.; Tsai, P.; Ha, N. (2014). IT enabled service delivery innovation from quality perspective. Multidisciplinary Journal for Education, Social and Technological Sciences. 1(1):17-52. doi:http://dx.doi.org/10.4995/muse.2014.2191.SWORD17521

Cluster Dynamical Mean-field calculations for TiOCl

Based on a combination of cluster dynamical mean field theory (DMFT) and density functional calculations, we calculated the angle-integrated spectral density in the layered $s=1/2$ quantum magnet TiOCl. The agreement with recent photoemission and oxygen K-edge X-ray absorption spectroscopy experiments is found to be good. Th e improvement achieved with this calculation with respect to previous single-site DMFT calculations is an indication of the correlated nature and low-dimensionality of TiOCl.Comment: 9 pages, 3 figures, improved version as publishe

Impact of diagnostic misclassification on estimation of genetic correlations using genome-wide genotypes

Disorders that share genetic risk factors often are placed in closely related diagnostic categories and treated similarly. Until recently, evidence for shared genetic etiology derived from classical research strategies – coaggregation in family and twin studies. Accumulating sufficient numbers of families was often problematic. However, in the era of genome-wide genotyping, we can now directly estimate the degree of sharing of genetic risk factors between disorders. This strategy is practical even for very rare disorders, where it is infeasible to ascertain informative families. Importantly, the estimates of genetic correlations from genome-wide genotypes are derived using such distant relatives that contamination by shared environmental factors seems unlikely. However, any method that seeks to quantify the shared etiology of disorders assumes they can be distinguished diagnostically from one another without error. Here we investigate the impact of misdiagnosis on estimates of genetic correlation both from traditional family data and from genome-wide genotypes of case–control samples from unrelated individuals. Our analyses show similar results for levels of misdiagnosis in both types of data. In both scenarios, genetic variances and heritabilities tend to be slightly underestimated but genetic correlations are overestimated, sometimes substantially so. For example, two genetically distinct but equally heritable disorders each with prevalence 1%, can generate false-positive estimates of genetic correlations of >0.2 in the presence of 10% reciprocal misdiagnosis. Strategies for minimizing the effects of misdiagnosis in cross-disorder genetic studies are discussed

Conditional Promotions and Consumer Overspending

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145509/1/poms12877.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145509/2/poms12877-sup-0001-SupInfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145509/3/poms12877_am.pd

Self-gravitating elastic bodies

Extended objects in GR are often modelled using distributional solutions of the Einstein equations with point-like sources, or as the limit of infinitesimally small "test" objects. In this note, I will consider models of finite self-gravitating extended objects, which make it possible to give a rigorous treatment of the initial value problem for (finite) extended objects.Comment: 16 pages. Based on a talk given at the 2013 WE-Heraeus seminar on "Equations of motion in relativistic gravity

Change in the treatment strategy for pediatric Crohn's disease

Crohn's disease is characterized by chronic inflammation involving any portion of the gastrointestinal tract. Treating Crohn's disease is a major challenge for clinicians, as no curative therapy currently exists. Pediatric Crohn's disease is characterized by frequent relapses, a wide extent of disease, a high prevalence of extraintestinal manifestations, and a severe clinical course. The classic therapeutic approach is known as the 'step-up' strategy, and follows a progressive course of treatment intensification as disease severity increases. Although this approach is usually effective for symptom control, many patients become either resistant to or dependent on corticosteroids. The efficacy of infliximab suggests that, rather than a progressive course of treatment, early intense induction may reduce complications associated with conventional treatment and improve quality of life. Intensive early therapy with infliximab is known as the 'top-down' strategy. Such therapy offers the potential for altering the natural history of Crohn's disease, and is changing treatment paradigms. However, the relatively new concept of an early aggressive or 'top-down' treatment approach is not yet widely accepted, especially in pediatric patients. The results of our current study demonstrate that early and intensive treatment of pediatric Crohn's disease patients with infliximab, at initial diagnosis, was more effective for maintaining remission and reducing flares