A Pseudo Dual All-Integer Algorithm for the Set Covering Problem

A modified linear programming method for the inequality or equality set covering problem (i.e., minimize cx subject to Ex ≥ b or Ex = b, where E is a zero-one matrix, b is a column of ones, and c is a nonnegative integral row) is presented. The almost unimodular property of the (zero-one) constraint matrix suggested an algorithm in which one performs (dual) simplex interactions whenever unit pivots are available and adjoin Gomory all-integer cuts when they are not. Finiteness, time reducing criteria, the elimination of roundoff errors, and applications to enumerative schemes are discussed. Preliminary computational experience, being very encouraging, is presented

A Dual All-Integer Algorithm (In Revised Simplex Form) for the Set Covering Problem

In an earlier work ( A Pseudo Dual All-Integer Algorithm for the Set Covering Problem , Department of Operations Research Tech. Memo. No. 204, CWRU, Nov. 1970) the authors developed a composite dual simplex-Gomory all integer algorithm for the (inequality or equality) set covering problem (i.e., minimize cx subject to Ex \u3e= e or Ex = e, xj = 0 or 1; where E is an m by n zero-one matrix, e is a column of ones, and c is a nonnegative integral row). Essentially the algorithm performs dual simplex iterations whenever unit pivots are available and it adjoins Gomory all integer cuts when they are not. In this way dual feasible all integer tableaux are maintained; optimality exists when primal feasibility is reached. Although this algorithm performed rather well, it required a working tableau of order n + 1 by m + n + 1. This meant that problems of only modest size could be solved. To overcome the storage problem a revised simplex form of the composite algorithm was developed. The details and computational results are presented in this report

'L'Invisible Voyeur du Monde des Voyants': Critiques of French Society in Michel Tournier's La Goutte d'or and Guy Hocquenghem's L'Amour en relief

Since decolonisation, the increase in immigration from France’s former colonies in North Africa has prompted metropolitan writers to reconsider conceptions of French society. In their novels, Tournier and Hocquenghem present contemporary France through the defamiliarising eyes of a North African immigrant who serves as a device for the critique of French culture. This article investigates the opposition between the objectifying culture of the West, and the immigrants’ desert culture. It argues that this opposition is flawed, and that the division is between actual practices of seeing and the cultural discourses around vision

Phage Displayed Short Peptides against Cells of Candida albicans Demonstrate Presence of Species, Morphology and Region Specific Carbohydrate Epitopes

Candida albicans is a commensal opportunistic pathogen, which can cause superficial infections as well as systemic infections in immuocompromised hosts. Among nosocomial fungal infections, infections by C. albicans are associated with highest mortality rates even though incidence of infections by other related species is on the rise world over. Since C. albicans and other Candida species differ in their susceptibility to antifungal drug treatment, it is crucial to accurately identify the species for effective drug treatment. Most diagnostic tests that differentiate between C. albicans and other Candida species are time consuming, as they necessarily involve laboratory culturing. Others, which employ highly sensitive PCR based technologies often, yield false positives which is equally dangerous since that leads to unnecessary antifungal treatment. This is the first report of phage display technology based identification of short peptide sequences that can distinguish C. albicans from other closely related species. The peptides also show high degree of specificity towards its different morphological forms. Using fluorescence microscopy, we show that the peptides bind on the surface of these cells and obtained clones that could even specifically bind to only specific regions of cells indicating restricted distribution of the epitopes. What was peculiar and interesting was that the epitopes were carbohydrate in nature. This gives insight into the complexity of the carbohydrate composition of fungal cell walls. In an ELISA format these peptides allow specific detection of relatively small numbers of C. albicans cells. Hence, if used in combination, such a test could help accurate diagnosis and allow physicians to initiate appropriate drug therapy on time

Empirical or microbiologically guided systemic antimicrobials as adjuncts to non-surgical periodontal therapy? A systematic review

BACKGROUND: It is unclear if patients with specific subgingival microbiological profiles benefit more from adjunctive systemic antibiotics.AIMS: To answer the question: 'What is the clinical benefit in periodontitis patients taking adjunctive systemic antimicrobials to non-surgical therapy, depending on pre-treatment detection of periodontopathogenic bacteria?'MATERIALS AND METHODS: A search was conducted in 4 electronic databases for randomised controlled trials reporting clinical outcomes following adjunctive antibiotic therapy for patients divided by baseline microbiological profiles.RESULTS: The initial search resulted in 643 papers, reduced to 5 after screening and author contact. Four of these studies were suitable for a fixed effects two-stage individual participant data meta-analysis adjusted for baseline data. Collectively, adjunctive Amoxicillin and Metronidazole yielded superior clinical results (measured as reduction of PPDs) compared to placebo. No significant differences were detected for the effect of adjunctive antibiotics by detection of A. actinomycetemcomitans on PPDs ≥ 5 mm (WMD=1.16, 95% CI[-5.37, 7.68], I2 =37.8%) or other clinical outcomes. All included studies had low risk of bias.CONCLUSION: There is no evidence to suggest that baseline detection of periodontopathogenic bacteria should be used as criterion for prescribing adjunctive antibiotics, although only limited information on microbial data and specific antimicrobials were available for analysis.</p

Solving the Multidimensional Knapsack Problem Using an Evolutionary Algorithm Hybridized with Branch and Bound

Abstract. A hybridization of an evolutionary algorithm (EA) with the branch and bound method (B&amp;B) is presented in this paper. Both tech-niques cooperate by exchanging information, namely lower bounds in the case of the EA, and partial promising solutions in the case of the B&amp;B. The multidimensional knapsack problem has been chosen as a bench-mark. To be precise, the algorithms have been tested on large problems instances from the OR-library. As it will be shown, the hybrid approach can provide high quality results, better than those obtained by the EA and the B&amp;B on their own.

Methodological issues in epidemiological studies of periodontitis - how can it be improved?

Background: This position paper was commissioned by the European Association of Dental Public Health, which has established six working groups to investigate the current status of six topics related to oral public health. One of these areas is epidemiology of periodontal diseases. Methods: Two theses "A systematic review of definitions of periodontitis and the methods that have been used to identify periodontitis" [1] and "Factors affecting community oral health care needs and provision" [2] formed the starting point for this position paper. Additional relevant and more recent publications were retrieved through a MEDLINE search. Results: The literature reveals a distinct lack of consensus and uniformity in the definition of periodontitis within epidemiological studies. There are also numerous differences in the methods used. The consequence is that data from studies using differing case definitions and differing survey methods are not easily interpretable or comparable. The limitations of the widely used Community Periodontal Index of Treatment Need (CPITN) and its more recent derivatives are widely recognized. Against this background, this position paper reviews the current evidence base, outlines existing problems and suggests how epidemiology of periodontal diseases may be improved. Conclusions: The remit of this working group was to review and discuss the existing evidence base of epidemiology of periodontal diseases and to identify future areas of work to further enhance it

Identification of gene targets against dormant phase Mycobacterium tuberculosis infections

<p>Abstract</p> <p>Background</p> <p><it>Mycobacterium tuberculosis</it>, the causative agent of tuberculosis (TB), infects approximately 2 billion people worldwide and is the leading cause of mortality due to infectious disease. Current TB therapy involves a regimen of four antibiotics taken over a six month period. Patient compliance, cost of drugs and increasing incidence of drug resistant <it>M. tuberculosis </it>strains have added urgency to the development of novel TB therapies. Eradication of TB is affected by the ability of the bacterium to survive up to decades in a dormant state primarily in hypoxic granulomas in the lung and to cause recurrent infections.</p> <p>Methods</p> <p>The availability of <it>M. tuberculosis </it>genome-wide DNA microarrays has lead to the publication of several gene expression studies under simulated dormancy conditions. However, no single model best replicates the conditions of human pathogenicity. In order to identify novel TB drug targets, we performed a meta-analysis of multiple published datasets from gene expression DNA microarray experiments that modeled infection leading to and including the dormant state, along with data from genome-wide insertional mutagenesis that examined gene essentiality.</p> <p>Results</p> <p>Based on the analysis of these data sets following normalization, several genome wide trends were identified and used to guide the selection of targets for therapeutic development. The trends included the significant up-regulation of genes controlled by <it>devR</it>, down-regulation of protein and ATP synthesis, and the adaptation of two-carbon metabolism to the hypoxic and nutrient limited environment of the granuloma. Promising targets for drug discovery were several regulatory elements (<it>devR/devS</it>, <it>relA</it>, <it>mprAB</it>), enzymes involved in redox balance and respiration, sulfur transport and fixation, pantothenate, isoprene, and NAD biosynthesis. The advantages and liabilities of each target are discussed in the context of enzymology, bacterial pathways, target tractability, and drug development.</p> <p>Conclusion</p> <p>Based on our bioinformatics analysis and additional discussion of in-depth biological rationale, several novel anti-TB targets have been proposed as potential opportunities to improve present therapeutic treatments for this disease.</p