Approximation algorithms for hard variants of the stable marriage and hospitals/residents problems

When ties and incomplete preference lists are permitted in the Stable Marriage and Hospitals/Residents problems, stable matchings can have different sizes. The problem of finding a maximum cardinality stable matching in this context is known to be NP-hard, even under very severe restrictions on the number, size and position of ties. In this paper, we describe polynomial-time 5/3-approximation algorithms for variants of these problems in which ties are on one side only and at the end of the preference lists. The particular variant is motivated by important applications in large scale centralised matching schemes

Branding the nation: Towards a better understanding

This paper aims to clarify some misunderstanding about nation branding. It examines the origins and interpretations of the concept, and draws a comparison between nation branding and commercial branding. A new definition is offered that emphasises the need to shift from “branding” the nation to nation image management

Prospective memory functioning among ecstasy/polydrug users: evidence from the Cambridge Prospective Memory Test (CAMPROMPT)

Rationale: Prospective memory (PM) deficits in recreational drug users have been documented in recent years. However, the assessment of PM has largely been restricted to self-reported measures that fail to capture the distinction between event-based and time-based PM. The aim of the present study is to address this limitation. Objectives: Extending our previous research, we augmented the range laboratory measures of PM by employing the CAMPROMPT test battery to investigate the impact of illicit drug use on prospective remembering in a sample of cannabis only, ecstasy/polydrug and non-users of illicit drugs, separating event and time-based PM performance. We also administered measures of executive function and retrospective memory in order to establish whether ecstasy/polydrug deficits in PM were mediated by group differences in these processes. Results: Ecstasy/polydrug users performed significantly worse on both event and time-based prospective memory tasks in comparison to both cannabis only and non-user groups. Furthermore, it was found that across the whole sample, better retrospective memory and executive functioning was associated with superior PM performance. Nevertheless, this association did not mediate the drug-related effects that were observed. Consistent with our previous study, recreational use of cocaine was linked to PM deficits. Conclusions: PM deficits have again been found among ecstasy/polydrug users, which appear to be unrelated to group differences in executive function and retrospective memory. However, the possibility that these are attributable to cocaine use cannot be excluded

Gate-tuned normal and superconducting transport at the surface of a topological insulator

Three-dimensional topological insulators are characterized by the presence of a bandgap in their bulk and gapless Dirac fermions at their surfaces. New physical phenomena originating from the presence of the Dirac fermions are predicted to occur, and to be experimentally accessible via transport measurements in suitably designed electronic devices. Here we study transport through superconducting junctions fabricated on thin Bi2Se3 single crystals, equipped with a gate electrode. In the presence of perpendicular magnetic field B, sweeping the gate voltage enables us to observe the filling of the Dirac fermion Landau levels, whose character evolves continuously from electron- to hole-like. When B=0, a supercurrent appears, whose magnitude can be gate tuned, and is minimum at the charge neutrality point determined from the Landau level filling. Our results demonstrate how gated nano-electronic devices give control over normal and superconducting transport of Dirac fermions at an individual surface of a three-dimensional topological insulator.Comment: 28 pages, 5 figure

A low density of 0.8 g/cc for the Trojan binary asteroid 617 Patroclus

The Trojan population consists of two swarms of asteroids following the same orbit as Jupiter and located at the L4 and L5 Lagrange points of the Jupiter-Sun system (leading and following Jupiter by 60 degrees). The asteroid 617 Patroclus is the only known binary Trojan (Merline et al. 2001). The orbit of this double system was hitherto unknown. Here we report that the components, separated by 680 km, move around the system centre of mass, describing roughly a circular orbit. Using the orbital parameters, combined with thermal measurements to estimate the size of the components, we derive a very low density of 0.8 g/cc. The components of Patroclus are therefore very porous or composed mostly of water ice, suggesting that they could have been formed in the outer part of the solar system.Comment: 10 pages, 3 figures, 1 tabl

Actinomycosis of the parotid masquerading as malignant neoplasm.

BACKGROUND: Primary actinomycosis of the parotid gland is of rare occurrence and can mimic a malignant neoplasm both clinically as well as radiologically. CASE PRESENTATION: We present here a case of primary actinomycosis of the parotid gland presenting with a parotid mass lesion with erosion of skull bones. CONCLUSIONS: Clinical presentation of cervico-facial actinomycosis is characterized by the presence of a suppurative or indurative mass with discharging sinuses. The lesion demonstrates characteristic features on fine needle aspiration cytology and histology, however at times the findings are equivocal

Timed inhibition of CDC7 increases CRISPR-Cas9 mediated templated repair.

Repair of double strand DNA breaks (DSBs) can result in gene disruption or gene modification via homology directed repair (HDR) from donor DNA. Altering cellular responses to DSBs may rebalance editing outcomes towards HDR and away from other repair outcomes. Here, we utilize a pooled CRISPR screen to define host cell involvement in HDR between a Cas9 DSB and a plasmid double stranded donor DNA (dsDonor). We find that the Fanconi Anemia (FA) pathway is required for dsDonor HDR and that other genes act to repress HDR. Small molecule inhibition of one of these repressors, CDC7, by XL413 and other inhibitors increases the efficiency of HDR by up to 3.5 fold in many contexts, including primary T cells. XL413 stimulates HDR during a reversible slowing of S-phase that is unexplored for Cas9-induced HDR. We anticipate that XL413 and other such rationally developed inhibitors will be useful tools for gene modification

Cocrystal structure of a class-I preQ1 riboswitch reveals a pseudoknot recognizing an essential hypermodified nucleobase

Riboswitches are mRNA domains that bind metabolites and modulate gene expression in cis. We report cocrystal structures of a remarkably compact riboswitch (34 nucleotides suffice for ligand recognition) from Bacillus subtilis selective for the essential nucleobase preQ1 (7-aminomethyl-7-deazaguanine). These reveal a previously unrecognized pseudoknot fold, and suggest a conserved gene-regulatory mechanism whereby ligand binding promotes sequestration of an RNA segment that otherwise assembles into a transcriptional anti-terminator

The diagnostic role of glycosaminoglycans in pleural effusions: A pilot study

<p>Abstract</p> <p>Background</p> <p>Pleural effusions are classified into transudates and exudates. Various criteria have been used with Light's et al being the most accepted ones. Glycosaminoglycans (GAGs) have been detected during pleural fluids (PF) analysis in various causes. In this pilot study, we investigated: (a) the usefulness of GAGs in the assessment of pleural effusions, and (b) whether and in what way GAGs correlate with established criteria used to indicate an exudate.</p> <p>Methods</p> <p>LDH, total protein, cholesterol and GAG levels were measured in pleural fluid and serum from 50 patients with pleural effusion. GAG levels were defined by the photometric method of Hata. The discriminative properties of pleural GAGs (pGAG), pleural fluid/serum GAG ratio (GAGR), serum GAGs (sGAG) and serum LDH (sLDH) were explored with ROC analysis.</p> <p>Results</p> <p>According to ROC analysis, pGAG and GAGR exhibited satisfactory discriminative properties in the separation of pleural effusions. For GAGR, at a 1.1 cut off point, sensitivity and specificity reached 75.6%; 95%CI: 60.5–87.1 and 100%; 95%CI: 47.8–100, respectively. For pGAG at a cut off value of 8.4 μg/ml, these percentages changed to 86.7%; 95%CI: 73.2–94.9 and 100%; 95%CI: 47.8–100. The study also revealed the differential role of sGAG between malignancies and benign cases, scoring 68.8%; 95%CI: 50.0–83.9 for sensitivity, and 84.6%; 95%CI: 54.5–97.6 for specificity at a 7.8 μg/ml cut off.</p> <p>Conclusion</p> <p>Our results suggest that glycosaminoglycan measurement of both serum and pleural effusions could be useful for simultaneous differentiation of exudates from transudates, and of malignant from benign exudates.</p

Scoliosis: density-equalizing mapping and scientometric analysis

<p>Abstract</p> <p>Background</p> <p>Publications related to scoliosis have increased enormously. A differentiation between publications of major and minor importance has become difficult even for experts. Scientometric data on developments and tendencies in scoliosis research has not been available to date. The aim of the current study was to evaluate the scientific efforts of scoliosis research both quantitatively and qualitatively.</p> <p>Methods</p> <p>Large-scale data analysis, density-equalizing algorithms and scientometric methods were used to evaluate both the quantity and quality of research achievements of scientists studying scoliosis. Density-equalizing algorithms were applied to data retrieved from ISI-Web.</p> <p>Results</p> <p>From 1904 to 2007, 8,186 items pertaining to scoliosis were published and included in the database. The studies were published in 76 countries: the USA, the U.K. and Canada being the most productive centers. The Washington University (St. Louis, Missouri) was identified as the most prolific institution during that period, and orthopedics represented by far the most productive medical discipline. "BRADFORD, DS" is the most productive author (146 items), and "DANSEREAU, J" is the author with the highest scientific impact (h-index of 27).</p> <p>Conclusion</p> <p>Our results suggest that currently established measures of research output (i.e. impact factor, h-index) should be evaluated critically because phenomena, such as self-citation and co-authorship, distort the results and limit the value of the conclusions that may be drawn from these measures. Qualitative statements are just tractable by the comparison of the parameters with respect to multiple linkages. In order to obtain more objective evaluation tools, new measurements need to be developed.</p