Audit on the use of radiological investigations in the management of rhinosinusitis

Objectives: The aim of this audit is to establish the cost to the Maltese health system from the use of radiological imaging in managing rhinosinusitis and to identify areas in which these costs can be minimised by following guidelines on the management of rhinosinusitis. Methods: All plain radiographs and computed tomography scans (CT) of the paranasal sinuses requested in the Mater Dei Hospital over a one year period were analysed. Data was collected regarding: the quantity of investigations ordered, age of the patients, cost and requesting department. Results: Over one year: 205 CT scans and 113 sets of plain radiographs of the paranasal sinuses were requested, costing a total of euro103,440. The majority (73%) were elective requests made by ENT consultants. Five percent of CT scans were requested for patients less than 10 years of age. Conclusion: Rhinosinusitis is diagnosed clinically, only requiring radiological investigation in more complex cases best managed by specialists in ENT. Plain radiographs have limited use in the management of rhinosinusitis. Judicious use of imaging requests whilst following clinical guidelines is required to save money and minimise patient exposure to ionising radiation.peer-reviewe

Finite-size effects lead to supercritical bifurcations in turbulent rotating Rayleigh-B\'enard convection

In turbulent thermal convection in cylindrical samples of aspect ratio \Gamma = D/L (D is the diameter and L the height) the Nusselt number Nu is enhanced when the sample is rotated about its vertical axis, because of the formation of Ekman vortices that extract additional fluid out of thermal boundary layers at the top and bottom. We show from experiments and direct numerical simulations that the enhancement occurs only above a bifurcation point at a critical inverse Rossby number 1/\Ro_c, with 1/\Ro_c \propto 1/\Gamma. We present a Ginzburg-Landau like model that explains the existence of a bifurcation at finite 1/\Ro_c as a finite-size effect. The model yields the proportionality between 1/\Ro_c and $1/\Gamma$ and is consistent with several other measured or computed system properties.Comment: 4 pages, 4 figure

Measuring the Robustness of Neural Networks via Minimal Adversarial Examples

Neural networks are highly sensitive to adversarial examples, which cause large output deviations with only small input perturbations. However, little is known quantitatively about the distribution and prevalence of such adversarial examples. To address this issue, we propose a rigorous search method that provably finds the smallest possible adversarial example. The key benefit of our method is that it gives precise quantitative insight into the distribution of adversarial examples, and guarantees the absence of adversarial examples if they are not found. The primary idea is to consider the nonlinearity exhibited by the network in a small region of the input space, and search exhaustively for adversarial examples in that region. We show that the frequency of adversarial examples and robustness of neural networks is up to twice as large as reported in previous works that use empirical adversarial attacks. In addition, we provide an approach to approximate the nonlinear behavior of neural networks, that makes our search method computationally feasible

Starburst in the Intragroup Medium of Stephan's Quintet

Based on new ISO mid-infrared observations and ground based $H_\alpha$ and near-infrared observations, we report the detection of a bright starburst in the intragroup medium (IGM) of the famous compact group of galaxies Stephan's Quintet (Source A in Fig.1). We demonstrate that this starburst is caused by a collision between a high velocity ($\delta$V$\sim$ 1000 km/sec) intruder galaxy (NGC7318b) and the IGM of the group. While this is the only starburst known today that is induced by a galaxy/cold-intergalactic-medium collision, it provides new constraints to the theory for interaction-induced starbursts, and may hint at a new mechanism for the star formation excess seen in more distant clusters.Comment: 17 pages, 2 PS figures. Accepted by Ap

Background error covariance estimation for atmospheric CO 2 data assimilation

In any data assimilation framework, the background error covariance statistics play the critical role of filtering the observed information and determining the quality of the analysis. For atmospheric CO 2 data assimilation, however, the background errors cannot be prescribed via traditional forecast or ensemble‐based techniques as these fail to account for the uncertainties in the carbon emissions and uptake, or for the errors associated with the CO 2 transport model. We propose an approach where the differences between two modeled CO 2 concentration fields, based on different but plausible CO 2 flux distributions and atmospheric transport models, are used as a proxy for the statistics of the background errors. The resulting error statistics: (1) vary regionally and seasonally to better capture the uncertainty in the background CO 2 field, and (2) have a positive impact on the analysis estimates by allowing observations to adjust predictions over large areas. A state‐of‐the‐art four‐dimensional variational (4D‐VAR) system developed at the European Centre for Medium‐Range Weather Forecasts (ECMWF) is used to illustrate the impact of the proposed approach for characterizing background error statistics on atmospheric CO 2 concentration estimates. Observations from the Greenhouse gases Observing SATellite “IBUKI” (GOSAT) are assimilated into the ECMWF 4D‐VAR system along with meteorological variables, using both the new error statistics and those based on a traditional forecast‐based technique. Evaluation of the four‐dimensional CO 2 fields against independent CO 2 observations confirms that the performance of the data assimilation system improves substantially in the summer, when significant variability and uncertainty in the fluxes are present. Key Points Difference in modeled CO2 fields is used to define background errors in CO2‐DA Both atmospheric transport & flux pattern differences impact background errors Evaluation using independent data shows positive impact on analysis estimatesPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100305/1/jgrd50654.pd

Colobops: a juvenile rhynchocephalian reptile (Lepidosauromorpha), not a diminutive archosauromorph with an unusually strong bite

Correctly identifying taxa at the root of major clades or the oldest clade-representatives is critical for meaningful interpretations of evolution. A small, partially crushed skull from the Late Triassic (Norian) of Connecticut, USA, originally described as an indeterminate rhynchocephalian saurian, was recently named Colobops noviportensis and reinterpreted as sister to all remaining Rhynchosauria, one of the earliest and globally distributed groups of herbivorous reptiles. It was also interpreted as having an exceptionally reinforced snout and powerful bite based on an especially large supratemporal fenestra. Here, after a re-analysis of the original scan data, we show that the skull was strongly dorsoventrally compressed post-mortem, with most bones out of life position. The cranial anatomy is consistent with that of other rhynchocephalian lepidosauromorphs, not rhynchosaurs. The ‘reinforced snout' region and the ‘exceptionally enlarged temporal region’ are preservational artefacts and not exceptional among clevosaurid rhynchocephalians. Colobops is thus not a key taxon for understanding diapsid feeding apparatus evolution

PTGER4 expression-modulating polymorphisms in the 5p13.1 region predispose to Crohn's disease and affect NF-κB and XBP1 binding sites.

Genome-wide association studies identified a PTGER4 expression-modulating region on chromosome 5p13.1 as Crohn's disease (CD) susceptibility region. The study aim was to test this association in a large cohort of patients with inflammatory bowel disease (IBD) and to elucidate genotypic and phenotypic interactions with other IBD genes. A total of 7073 patients and controls were genotyped: 844 CD and 471 patients with ulcerative colitis and 1488 controls were analyzed for the single nucleotide polymorphisms (SNPs) rs4495224 and rs7720838 on chromosome 5p13.1. The study included two replication cohorts of North American (CD: n = 684; controls: n = 1440) and of German origin (CD: n = 1098; controls: n = 1048). Genotype-phenotype, epistasis and transcription factor binding analyses were performed. In the discovery cohort, an association of rs4495224 (p = 4.10×10⁻⁵; 0.76 [0.67-0.87]) and of rs7720838 (p = 6.91×10⁻⁴; 0.81 [0.71-0.91]) with susceptibility to CD was demonstrated. These associations were confirmed in both replication cohorts. In silico analysis predicted rs4495224 and rs7720838 as essential parts of binding sites for the transcription factors NF-κB and XBP1 with higher binding scores for carriers of the CD risk alleles, providing an explanation of how these SNPs might contribute to increased PTGER4 expression. There was no association of the PTGER4 SNPs with IBD phenotypes. Epistasis detected between 5p13.1 and ATG16L1 for CD susceptibility in the discovery cohort (p = 5.99×10⁻⁷ for rs7720838 and rs2241880) could not be replicated in both replication cohorts arguing against a major role of this gene-gene interaction in the susceptibility to CD. We confirmed 5p13.1 as a major CD susceptibility locus and demonstrate by in silico analysis rs4495224 and rs7720838 as part of binding sites for NF-κB and XBP1. Further functional studies are necessary to confirm the results of our in silico analysis and to analyze if changes in PTGER4 expression modulate CD susceptibility

Genomic islands of speciation separate cichlid ecomorphs in an East African crater lake

The genomic causes and effects of divergent ecological selection during speciation are still poorly understood. Here, we report the discovery and detailed characterization of early-stage adaptive divergence of two cichlid fish ecomorphs in a small (700m diameter) isolated crater lake in Tanzania. The ecomorphs differ in depth preference, male breeding color, body shape, diet and trophic morphology. With whole genome sequences of 146 fish, we identify 98 clearly demarcated genomic ‘islands’ of high differentiation and demonstrate association of genotypes across these islands to divergent mate preferences. The islands contain candidate adaptive genes enriched for functions in sensory perception (including rhodopsin and other twilight vision associated genes), hormone signaling and morphogenesis. Our study suggests mechanisms and genomic regions that may play a role in the closely related mega-radiation of Lake Malawi.The work was funded by Royal Society-Leverhulme Trust Africa Awards AA100023 and AA130107 (M.J.G., B.P.N. and G.F.T.), a Wellcome Trust PhD studentship grant 097677/Z/11/Z (M.M.), Wellcome Trust grant WT098051 (S.S. and R.D.), Wellcome Trust and Cancer Research UK core support and a Wellcome Trust Senior Investigator Award (E.A.M.), a Leverhulme Trust Research Fellowship RF-2014-686 (M.J.G.), a University of Bristol Research Committee award (M.G.), a Bangor University Anniversary PhD studentship (to A.M.T.) and a Fisheries Society of the British Isles award (G.F.T.). Raw sequencing reads are in the SRA nucleotide archive: RAD sequencing (BioProject: PRJNA286304; accessions SAMN03768857 to SAMN03768912) and whole genome sequencing (BioProject PRJEB1254: sample accessions listed in Table S16). The RAD based phylogeny and alignments have been deposited in TreeBase (TB2:S18241). Whole genome variant calls in the VCF format, phylogenetic trees, and primer sequences for Sequenom genotyping are available from the Dryad Digital Repository (http://dx.doi.org/10.5061/dryad.770mc). RD declares his interests as a founder and non-executive director of Congenica Ltd., that he owns stock in Illumina from previous consulting, and is a scientific advisory board member of Dovetail Inc. We thank R. Schley for generating pharyngeal jaw data; S. Mzighani, J. Kihedu and staff of the Tanzanian Fisheries Research Institute for logistical support; A. Smith, H. Sungani, A. Shechonge, P. Parsons, J. Swanstrom, G. Cooke and J. Bridle for contributions to sampling and aquarium maintenance, the Sanger Institute sequencing core for DNA sequencing and Dr. H. Imai (Kyoto University) for the use of spectrometer in his laboratory.This is the author accepted manuscript. The final version is available from AAAS via http://dx.doi.org/10.1126/science.aac992