O Canada! Our Fathers\u27 Land of Cld. : O Canada! Terre de nos aieux!

https://digitalcommons.library.umaine.edu/mmb-vp/4516/thumbnail.jp

Structural Rounding: Approximation Algorithms for Graphs Near an Algorithmically Tractable Class

We develop a framework for generalizing approximation algorithms from the structural graph algorithm literature so that they apply to graphs somewhat close to that class (a scenario we expect is common when working with real-world networks) while still guaranteeing approximation ratios. The idea is to edit a given graph via vertex- or edge-deletions to put the graph into an algorithmically tractable class, apply known approximation algorithms for that class, and then lift the solution to apply to the original graph. We give a general characterization of when an optimization problem is amenable to this approach, and show that it includes many well-studied graph problems, such as Independent Set, Vertex Cover, Feedback Vertex Set, Minimum Maximal Matching, Chromatic Number, (l-)Dominating Set, Edge (l-)Dominating Set, and Connected Dominating Set. To enable this framework, we develop new editing algorithms that find the approximately-fewest edits required to bring a given graph into one of a few important graph classes (in some cases these are bicriteria algorithms which simultaneously approximate both the number of editing operations and the target parameter of the family). For bounded degeneracy, we obtain an O(r log{n})-approximation and a bicriteria (4,4)-approximation which also extends to a smoother bicriteria trade-off. For bounded treewidth, we obtain a bicriteria (O(log^{1.5} n), O(sqrt{log w}))-approximation, and for bounded pathwidth, we obtain a bicriteria (O(log^{1.5} n), O(sqrt{log w} * log n))-approximation. For treedepth 2 (related to bounded expansion), we obtain a 4-approximation. We also prove complementary hardness-of-approximation results assuming P != NP: in particular, these problems are all log-factor inapproximable, except the last which is not approximable below some constant factor 2 (assuming UGC)

Translating clinical and patient-reported data to tailored shared decision reports with predictive analytics for knee and hip arthritis

INTRODUCTION: New informatics tools can transform evidence-based information to individualized predictive reports to serve shared decisions in clinic. We developed a web-based system to collect patient-reported outcomes (PROs) and medical risk factors and to compare responses to national registry data. The system generates predicted outcomes for individual patients and a report for use in clinic to support decisions. We present the report development, presentation, and early experience implementing this PRO-based, shared decision report for knee and hip arthritis patients seeking orthopedic evaluation. METHODS: Iterative patient and clinician interviews defined report content and visual display. The web-system supports: (a) collection of PROs and risk data at home or in office, (b) automated statistical processing of responses compared to national data, (c) individualized estimates of likely pain relief and functional gain if surgery is elected, and (d) graphical reports to support shared decisions. The system was implemented at 12 sites with 26 surgeons in an ongoing cluster randomized trial. RESULTS: Clinicians and patients recommended that pain and function as well as clinical risk factors (e.g., BMI, smoking) be presented to frame the discussion. Color and graphics support patient understanding. To date, 7891 patients completed the assessment before the visit and 56% consented to study participation. Reports were generated for 98% of patients and 68% of patients recalled reviewing the report with their surgeon. CONCLUSIONS: Informatics solutions can generate timely, tailored office reports including PROs and predictive analytics. Patients successfully complete the pre-visit PRO assessments and clinicians and patients value the report to support shared surgical decisions

Efficient routing protocols in nameless networks

Projet PARADISTwo types of distributed fully asynchronous probabilistic algorithms are given in the present paper which elect a leader and find a spanning tree in arbitrary anonymous networks of processes. Our algorithms are simpler and slightly improve on those with respect to communication complexity. So far, the present algorithms are very likely to be the first fully and precisely specified distributed communication protocols for nameless networks. They are basically patterned upon the spanning tree algorithm designed and motivated by the previous works proposed. For the case where no bound is known on the network size, we give a message terminating algorithm with error probability e which requires 0(m log log(nr) + n log n) messages on the average, each of size 0(log r + log log n) where n and m are the number of nodes and links in the network and r = 1/e. In the case where some bounds are known on n (N < n ² KN, with K ³ 1), we give a process terminating algorithm with error probability e, with 0(m + n log n) messages of size 0(log n) in the worst case. In either case, the (virtual) time complexity is 0(D x log log(nr)). In the particular case where the exact value of n is known a variant of the preceding algorithm process terminates and always succeeds in 0(m + n log n) messages of size 0(log n)

Un algorithme probabiliste d'election et d'arbre couvrant sur des reseaux anonymes

Dans le present rapport, nous proposons deux variantes d'un algorithme distribue, probabiliste, asynchrone d'election et de construction d'arbre couvrant dans des reseaux anonymes a topologie quelconque. A notre connaissance, cet algorithme est le premier du genre, a etre totalement et rigoureusement specifie. Il est fonde sur un precedent algorithme deterministe d'election pour reseaux de processus a identites distinctes. Nous montrons ici comment construire les deux variantes, suivant deux contextes differents. Premierement- , nous considerons le cas ou on ne possede strictement aucune connaissance globale sur le reseau, ce qui conduit a un algorithme dans lequel on n'opere qu'un nombre limite, fixe d'avance, de tirages aleatoires. Il n'y a pas alors de moyen deterministe d'obtenir une "bonne" terminaison distribuee, et l'election comme la construction d'un arbre couvrant sont realises avec une probabilite ³ 1 - e, pour e > 0 donne. Et deuxiemement, en supposant qu'un processus au moins connaisse n le nombre total de processus du systeme, le probleme de l'election et de l'arbre couvrant sont resolus avec une terminaison correcte de l'algorithme, sans erreur. La terminaison correcte de l'algorithme tient ici au fait que l'un des processus finit par apprendre qu'il appartient a un arbre a n sommets, cet arbre est alors bien un arbre couvrant du reseau

Early predictors of separation anxiety disorder : early stranger anxiety, parental pathology and prenatal factors

&lt;i&gt;Objective:&lt;/i&gt; The present study seeks to extend research on the etiology of separation anxiety disorder (SAD) in a German-speaking sample by examining differences between children with SAD and healthy comparisons, using a retrospective-reporting paradigm. &lt;i&gt;Method:&lt;/i&gt; The sample included 106 children with SAD and 44 healthy children between the ages of 4 and 14 years. Parents completed questionnaires and structured clinical interviews to assess parental pathology, pregnancy variables and strong early stranger anxiety. &lt;i&gt;Results:&lt;/i&gt; Children with SAD were more likely than healthy children to have had a phase of stronger stranger anxiety in infancy. Further, early stranger anxiety remained a significant predictor of SAD after controlling for maternal depression. Meaningful effects were not found for the influence of parental age at birth or other pregnancy factors. &lt;i&gt;Conclusion:&lt;/i&gt; This study provides beginning evidence of the potential predictive value of strong stranger anxiety in distinguishing children with SAD from those with no disorder, above and beyond the influence of parental pathology.</jats:p

DNA waves and water

Some bacterial and viral DNA sequences have been found to induce low frequency electromagnetic waves in high aqueous dilutions. This phenomenon appears to be triggered by the ambient electromagnetic background of very low frequency. We discuss this phenomenon in the framework of quantum field theory. A scheme able to account for the observations is proposed. The reported phenomenon could allow to develop highly sensitive detection systems for chronic bacterial and viral infections.Comment: Invited talk at the DICE2010 Conference, Castiglioncello, Italy September 201