Planar Disjoint-Paths Completion

We introduce Planar Disjoint Paths Completion, a completion counterpart of the Disjoint Paths problem, and study its parameterized complexity. The problem can be stated as follows: given a, not necessarily connected, plane graph G, k pairs of terminals, and a face F of G, find a minimum-size set of edges, if one exists, to be added inside F so that the embedding remains planar and the pairs become connected by k disjoint paths in the augmented network. Our results are twofold: first, we give an upper bound on the number of necessary additional edges when a solution exists. This bound is a function of k, independent of the size of G. Second, we show that the problem is fixed-parameter tractable, in particular, it can be solved in time f(k) · n2

Validation of nonlinear PCA

Linear principal component analysis (PCA) can be extended to a nonlinear PCA by using artificial neural networks. But the benefit of curved components requires a careful control of the model complexity. Moreover, standard techniques for model selection, including cross-validation and more generally the use of an independent test set, fail when applied to nonlinear PCA because of its inherent unsupervised characteristics. This paper presents a new approach for validating the complexity of nonlinear PCA models by using the error in missing data estimation as a criterion for model selection. It is motivated by the idea that only the model of optimal complexity is able to predict missing values with the highest accuracy. While standard test set validation usually favours over-fitted nonlinear PCA models, the proposed model validation approach correctly selects the optimal model complexity.Comment: 12 pages, 5 figure

Children and older adults exhibit distinct sub-optimal cost-benefit functions when preparing to move their eyes and hands

"© 2015 Gonzalez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited"Numerous activities require an individual to respond quickly to the correct stimulus. The provision of advance information allows response priming but heightened responses can cause errors (responding too early or reacting to the wrong stimulus). Thus, a balance is required between the online cognitive mechanisms (inhibitory and anticipatory) used to prepare and execute a motor response at the appropriate time. We investigated the use of advance information in 71 participants across four different age groups: (i) children, (ii) young adults, (iii) middle-aged adults, and (iv) older adults. We implemented 'cued' and 'non-cued' conditions to assess age-related changes in saccadic and touch responses to targets in three movement conditions: (a) Eyes only; (b) Hands only; (c) Eyes and Hand. Children made less saccade errors compared to young adults, but they also exhibited longer response times in cued versus non-cued conditions. In contrast, older adults showed faster responses in cued conditions but exhibited more errors. The results indicate that young adults (18 -25 years) achieve an optimal balance between anticipation and execution. In contrast, children show benefits (few errors) and costs (slow responses) of good inhibition when preparing a motor response based on advance information; whilst older adults show the benefits and costs associated with a prospective response strategy (i.e., good anticipation)

Unusual presentation of thyrotoxicosis as complete heart block and renal failure: a case report

<p>Abstract</p> <p>Introduction</p> <p>Thyrotoxicosis is a clinical entity often very difficult to diagnose without biochemical confirmation as its clinical features can be highly varied. The most common cardiac manifestations of thyrotoxicosis are resting sinus tachycardia, supraventricular tachycardia including atrial fibrillation and atrial flutter with or without cardiac failure. Bradycardia and atrio-ventricular conduction defects are very uncommon in thyrotoxicosis.</p> <p>Case presentation</p> <p>We report the case of a 59-year-old Caucasian man presenting with progressive weight loss, abnormal liver function, acute renal failure and complete heart block due to thyrotoxicosis.</p> <p>Conclusion</p> <p>Thyrotoxicosis should be considered as a possible diagnosis in patients with bradycardia and heart blocks associated with abnormal symptoms like weight loss. Nevertheless, the clinical, electrophysiological and biochemical abnormalities associated with thyrotoxicosis may be completely reversible restoring euthyroid state.</p

NP-Completeness Results for Graph Burning on Geometric Graphs

Graph burning runs on discrete time steps. The aim is to burn all the vertices in a given graph in the least number of time steps. This number is known to be the burning number of the graph. The spread of social influence, an alarm, or a social contagion can be modeled using graph burning. The less the burning number, the faster the spread. Optimal burning of general graphs is NP-Hard. There is a 3-approximation algorithm to burn general graphs where as better approximation factors are there for many sub classes. Here we study burning of grids; provide a lower bound for burning arbitrary grids and a 2-approximation algorithm for burning square grids. On the other hand, burning path forests, spider graphs, and trees with maximum degree three is already known to be NP-Complete. In this article we show burning problem to be NP-Complete on connected interval graphs, permutation graphs and several other geometric graph classes as corollaries.Comment: 17 pages, 5 figure

Mutations in pericentrin cause Seckel syndrome with defective ATR-dependent DNA damage signaling

Large brain size is one of the defining characteristics of modern humans. Seckel syndrome (MIM 210600), a disorder of markedly reduced brain and body size, is associated with defective ATR-dependent DNA damage signaling. Only a single hypomorphic mutation of ATR has been identified in this genetically heterogeneous condition. We now report that mutations in the gene encoding pericentrin (PCNT)--resulting in the loss of pericentrin from the centrosome, where it has key functions anchoring both structural and regulatory proteins--also cause Seckel syndrome. Furthermore, we find that cells of individuals with Seckel syndrome due to mutations in PCNT (PCNT-Seckel) have defects in ATR-dependent checkpoint signaling, providing the first evidence linking a structural centrosomal protein with DNA damage signaling. These findings also suggest that other known microcephaly genes implicated in either DNA repair responses or centrosomal function may act in common developmental pathways determining human brain and body size

Prenatal ultrasound and postmortem histologic evaluation of tooth germs: an observational, transversal study

Introduction: Hypodontia is the most frequent developmental anomaly of the orofacial complex, and its detection in prenatal ultrasound may indicate the presence of congenital malformations, genetic syndromes and chromosomal abnormalities.To date, only a few studies have evaluated the histological relationship of human tooth germs identified by two-dimensional (2D) ultrasonography. In order to analyze whether two-dimensional ultrasonography of tooth germs may be successfully used for identifying genetic syndromes, prenatal ultrasound images of fetal tooth germs obtained from a Portuguese population sample were compared with histological images obtained from fetal autopsies.Methods: Observational, descriptive, transversal study. The study protocol followed the ethical principles outlined by the Helsinki Declaration and was approved by the Ethics Committee of the School of Dental Medicine, University of Porto (FMDUP, Porto, Portugal) and of the Centro Hospitalar de Vila Nova de Gaia/Espinho (CHVNG/EPE, Porto, Portugal) as well as by the CGC Genetics Embryofetal Pathology Laboratory. Eighty-five fetuses examined by prenatal ultrasound screening from May 2011 to August 2012 had an indication for autopsy following spontaneous fetal death or medical termination of pregnancy. Of the 85 fetuses, 37 (43.5%) were randomly selected for tooth germ evaluation by routine histopathological analysis. Fetuses who were up to 30 weeks of gestation, and whose histological pieces were not representative of all maxillary tooth germs was excluded. Twenty four fetus between the 13th and 30th weeks of gestation fulfilled the parameters to autopsy.Results: Twenty four fetuses were submitted to histological evaluation and were determined the exact number, morphology, and mineralization of their tooth germs. All tooth germs were identifiable with ultrasonography as early as the 13th week of gestation. Of the fetuses autopsied, 41.7% had hypodontia (29.1% maxillary hypodontia and 20.9% mandibular hypodontia).Conclusions: This results indicateinfo:eu-repo/semantics/publishedVersio

Conceptualizing pathways linking women's empowerment and prematurity in developing countries.

BackgroundGlobally, prematurity is the leading cause of death in children under the age of 5. Many efforts have focused on clinical approaches to improve the survival of premature babies. There is a need, however, to explore psychosocial, sociocultural, economic, and other factors as potential mechanisms to reduce the burden of prematurity. Women's empowerment may be a catalyst for moving the needle in this direction. The goal of this paper is to examine links between women's empowerment and prematurity in developing settings. We propose a conceptual model that shows pathways by which women's empowerment can affect prematurity and review and summarize the literature supporting the relationships we posit. We also suggest future directions for research on women's empowerment and prematurity.MethodsThe key words we used for empowerment in the search were "empowerment," "women's status," "autonomy," and "decision-making," and for prematurity we used "preterm," "premature," and "prematurity." We did not use date, language, and regional restrictions. The search was done in PubMed, Population Information Online (POPLINE), and Web of Science. We selected intervening factors-factors that could potentially mediate the relationship between empowerment and prematurity-based on reviews of the risk factors and interventions to address prematurity and the determinants of those factors.ResultsThere is limited evidence supporting a direct link between women's empowerment and prematurity. However, there is evidence linking several dimensions of empowerment to factors known to be associated with prematurity and outcomes for premature babies. Our review of the literature shows that women's empowerment may reduce prematurity by (1) preventing early marriage and promoting family planning, which will delay age at first pregnancy and increase interpregnancy intervals; (2) improving women's nutritional status; (3) reducing domestic violence and other stressors to improve psychological health; and (4) improving access to and receipt of recommended health services during pregnancy and delivery to help prevent prematurity and improve survival of premature babies.ConclusionsWomen's empowerment is an important distal factor that affects prematurity through several intervening factors. Improving women's empowerment will help prevent prematurity and improve survival of preterm babies. Research to empirically show the links between women's empowerment and prematurity is however needed

Rapidly progressive Bronchiolitis Obliterans Organising Pneumonia presenting with pneumothorax, persistent air leak, acute respiratory distress syndrome and multi-organ dysfunction: a case report

<p>Abstract</p> <p>Introduction</p> <p>Bronchiolitis Obliterans Organising Pneumonia (BOOP) may often present initially as a recurrent spontaneous pneumothorax and then develop multi-system complications.</p> <p>Case presentation</p> <p>A 17-year-old boy presented with a pneumothorax, which developed into rapidly progressive Bronchiolitis Obliterans Organising Pneumonia (BOOP). He developed multi-organ dysfunction (including adult respiratory distress syndrome, oliguric renal failure, acute coronary syndrome, cardiac failure and a right atrial thrombus) which necessitated prolonged intensive care. Diagnosis was confirmed on open lung biopsy and he responded well to treatment with corticosteroids.</p> <p>Conclusion</p> <p>BOOP is exquisitely sensitive to oral corticosteroids but if the diagnosis is not considered in such patients and appropriate treatment instituted early, BOOP may often lead to prolonged hospital admission with considerable morbidity.</p