Geographical differences in first acquisition of Pseudomonas aeruginosa in cystic fibrosis

RATIONALE: Risk of infection with Pseudomonas aeruginosa in cystic fibrosis (CF) may be associated with environmental factors.

OBJECTIVES: To determine whether residential location is associated with risk of first acquisition of P. aeruginosa.

METHODS: We performed bronchoalveolar lavage and upper airway cultures in children newly diagnosed with CF to identify infection with P. aeruginosa during infancy and early childhood. Children were assessed according to their residence in a regional or metropolitan area. Multilocus sequence typing was used to determine P. aeruginosa genotype. An environmental questionnaire was also administered.

MEASUREMENTS AND MAIN RESULTS: A total of 105 of 120 (87.5%) infants diagnosed with CF were included in this study. Diagnosis in 65 infants (61.9%) followed newborn screening at mean age of 4.6 weeks. Sixty subjects (57.1%) were homozygous ΔF508, and 47 (44.8%) were female. Fifty-five (52.3%) infants were regional, of whom 26 (47.3%), compared with 9 of 50 (18.0%) metropolitan children, acquired infection with P. aeruginosa (odds ratio, 4.084; 95% confidence interval, 1.55-11.30). Age at acquisition was similar (regional: median, 2.31 yr; range, 0.27-5.96 yr; metropolitan: median, 3.10 yr, range, 0.89-3.70 yr). Strain typing identified P. aeruginosa genotypes often encountered in different ecological settings and little evidence of cross-infection. Ninety questionnaires (85.7%) were completed. Those who acquired P. aeruginosa were more likely to be living in a household that used water sprinkler systems (P = 0.032), but no differences were identified to explain increased risk of acquisition of P. aeruginosa in regional children.

CONCLUSIONS: Geographical difference in residence of children with CF was associated with increased risk of first acquisition of P. aeruginosa, usually with strains associated with the environment rather than with cross-infection.

Methylated Arsenic Species in Rice:Geographical Variation, Origin, and Uptake Mechanisms

Rice is a major source of inorganic arsenic (iAs) in the human diet because paddy rice. efficient at accumulating As Rice As speciation is dominated by iAs and dimethylarsinic acid (DMA). Here we review the global pattern in rice As speciation and the factors causing the variation. Rice produced in Asia shows a strong linear relationship between iAs and total As concentration with a slope of 0.78. Rice produced in Europe and the United States shows a more variable, but generally hyperbolic relationship with DMA being predominant in U.S. rice. Although there is significant genotypic variation in grain As speciation, the regional Variations are primarily attributed to environmental factors. Emerging evidence also indicates that methylated. As species in rice are derived from the soil, while rice plants lack the As methylation ability. Soil flooding and additions of organic matter increase microbial methylation of As, although the microbial community responsible for methylafion is poorly understood. Compared with iAs, methylated As species are taken up by rice roots less efficiently but are transported to the grain much, more efficiently, which may be an important factor responsible for the spikelet sterility disorder (straight head disease) in rice. DMA is a weak carcinogen, but the level of ingestion from rice consumption is much lower than that of concern. Questions that require further investigations are identified.

The imprint of the geographical, evolutionary and ecological context on species-area relationships

Species-area relationships (SAR) are fundamental in the understanding of biodiversity patterns and of critical importance for predicting species extinction risk worldwide. Despite the enormous attention given to SAR in the form of many individual analyses, little attempt has been made to synthesize these studies. We conducted a quantitative meta-analysis of 794 SAR, comprising a wide span of organisms, habitats and locations. We identified factors reflecting both pattern-based and dynamic approaches to SAR and tested whether these factors leave significant imprints on the slope and strength of SAR. Our analysis revealed that SAR are significantly affected by variables characterizing the sampling scheme, the spatial scale, and the types of organisms or habitats involved. We found that steeper SAR are generated at lower latitudes and by larger organisms. SAR varied significantly between nested and independent sampling schemes and between major ecosystem types, but not generally between the terrestrial and the aquatic realm. Both the fit and the slope of the SAR were scale-dependent. We conclude that factors dynamically regulating species richness at different spatial scales strongly affect the shape of SAR. We highlight important consequences of this systematic variation in SAR for ecological theory, conservation management and extinction risk predictions.

The geographical structure of British bird distributions:diversity, spatial turnover and scale

1. Using data on the spatial distribution of the British avifauna, we address three basic questions about the spatial structure of assemblages: (i) Is there a relationship between species richness (alpha diversity) and spatial turnover of species (beta diversity)? (ii) Do high richness locations have fewer species in common with neighbouring areas than low richness locations?, and (iii) Are any such relationships contingent on spatial scale (resolution or quadrat area), and do they reflect the operation of a particular kind of species-area relationship (SAR)?

2. For all measures of spatial turnover, we found a negative relationship with species richness. This held across all scales, with the exception of turnover measured as beta (sim).

3. Higher richness areas were found to have more species in common with neighbouring areas.

4. The logarithmic SAR fitted better than the power SAR overall, and fitted significantly better in areas with low richness and high turnover.

5. Spatial patterns of both turnover and richness vary with scale. The finest scale richness pattern (10 km) and the coarse scale richness pattern (90 km) are statistically unrelated. The same is true of the turnover patterns.

6. With coarsening scale, locations of the most species-rich quadrats move north. This observed sensitivity of richness 'hotspot' location to spatial scale has implications for conservation biology, e.g. the location of a reserve selected on the basis of maximum richness may change considerably with reserve size or scale of analysis.

7. Average turnover measured using indices declined with coarsening scale, but the average number of species gained or lost between neighbouring quadrats was essentially scale invariant at 10-13 species, despite mean richness rising from 80 to 146 species (across an 81-fold area increase). We show that this kind of scale invariance is consistent with the logarithmic SAR.

Population genetic analyses reveal distinct geographical blooms of the jellyfish Rhizostoma octopus (Scyhpozoa)

Understanding the spatial integrity and connectivity of jellyfish blooms is important for ecologists and coastal stakeholders alike. Previous studies have shown that the distribution of jellyfish blooms can display a marked consistency in space and time, suggesting that such patterns cannot be attributed to passive processes alone. In the present study, we used a combination of microsatellite markers and mitochondrial cytochrome oxidase I sequences to investigate genetic structuring of the scyphozoan jellyfish Rhizostoma octopus in the Irish and Celtic Seas. The mitochondrial data indicated far higher levels of population differentiation than the microsatellites: ΦST[MT] = 0.300 vs. ΦST[NUC] = 0.013. Simulation studies indicated that the low levels of nuclear differentiation were not the result of limited power because of low levels of polymorphism. These findings, supported by palaeodistribution modelling and mismatch distribution analysis, are consistent with expansion of R. octopus from a single, limited refugium after the Last Glacial Maximum, followed by subsequent isolation, and that the discrepancy between the mitochondrial and nuclear markers is a result of the nuclear loci taking longer to reach mutation–drift equilibrium following the expansion as a result of their four-fold larger effective population size. The populations studied are probably not well connected via gene flow, and thus genetically as well as geographically distinct, although our findings also highlight the need to use a combination of organellar and nuclear markers to enable a more complete understanding of population demography and structure, particularly for species with large effective population sizes.

Phylogeographical analyses of shellfish viruses: inferring a geographical origin for ostreid herpesviruses OsHV-1 (Malacoherpesviridae)

Mortality episodes have regularly been affecting the shellfish industry throughout its history. Some of these mortalities, especially in the oyster industry, have been attributed to herpesviruses. Purification of viral particles and molecular characterization have led to the development of routine monitoring, as well as improved taxonomic classification. Ostreid herpesviruses (Malacoherpesviridae), mostly affecting Pacific oysters Crassostrea gigas, have been sporadically recorded in the French oyster industry since the early 1990s (OsHV-1 'reference'). From 2008, a new variant of ostreid herpesvirus (OsHV-1 mu Var) has emerged and seriously impacted oyster production in France and other European countries. Consequently, the presence of ostreid herpesviruses has been monitored in different oyster producing areas around the world. The present study compiles molecular data that are available from survey efforts and takes a biogeographical approach, in order to infer an origin for ostreid herpesviruses. The highest genotype diversity was found in East Asia, despite a lower survey effort in that area than in Europe. Genotype network analyses show that both populations of ostreid herpesviruses present in Europe (OsHV-1 'reference' and OsHV-1 mu Var) are closely related to genotypes recorded in Asia. Moreover, ostreid herpesviruses have been detected in wild and symptom-free populations of various Asian native Crassostrea species. In the rest of the world, ostreid herpesvirus genotypes were recorded from cultivated C. gigas, and mostly associated with mortality episodes. Results of this study are therefore highly suggestive of an Asian origin for these viruses, which can be pathogenic under farming conditions. It also highlights the risks of European stock improvements, by means of overseas shellfish imports.

MULTIPLE-SCATTERING EFFECTS IN ELECTRON HOLOGRAPHIC IMAGES

An exact multiple-scattering formalism is used to simulate a wave multiply scattered from a cluster, and this is used to provide a direct quantitative analysis of the influence of multiple scattering on holographic imaging. Although multiple scattering may help in identifying atomic positions in real space, we show that it does cause a loss of resolution. We also show that a filter function can considerably reduce the multiple-scattering contribution to holographic images.

HOLOGRAPHIC IMAGES OF IODINE ATOMS ON A SILVER SURFACE FROM ELECTRON-EMISSION PATTERNS

BARTON 1 has suggested that photoelectron interference patterns may be used directly as holograms to obtain atomic-resolution images of surface structures. Bulk structures have been obtained previously by this means from experimental patterns of high-energy Kikuchi(quasi-elastically scattered) and Auger electrons 2,3. Here we test the feasibility of this technique for determination of surface structures using Auger intensity patterns obtained 4,5 from iodine chemisorbed on a pseudomorphic silver monolayer on Pt{111}. By direct numerical holographic inversion, we obtain three-dimensional images which show that iodine adatoms are located in hollows of 3-fold symmetry on the surface. The images yield the site symmetry with good atomic resolution in the surface plane, but suffer from poor resolution along the Ag-I axis. We anticipate that data with better angular resolution obtained at low temperatures would improve the spatial resolution of such images.

Seasonal and geographical differences in aflatoxin exposures in Senegal

The aim of the study was to determine the geographical and seasonal variations in aflatoxin dietary exposure levels in adults from Senegal. A total of 168 adults (50% male) were recruited from three districts: Nioro du Rip (n=90), located in the Sudan Savannah agro-ecological zone where rainfall is sufficient for groundnut growth; Saint-Louis (n=40) and Mboro (n=38), located in the Sahel zone where groundnuts are produced under irrigated conditions. Diet information and samples were collected at groundnut harvest and post-harvest seasons. Plasma aflatoxin-albumin adducts (AF-alb) and total aflatoxin in household groundnut samples were measured by ELISA and a quantitative thin layer chromatography method, respectively. The blood AF-alb geometric mean was 45.7 pg/mg albumin (range 5.5-588.2 pg/mg). Nioro du Rip had a higher AF-alb level at harvest than Saint-Louis and Mboro (80.0 vs 15.6 and 33.3 pg/mg, P<0.001). Similar trends were observed at post-harvest (P<0.05). Seasonal trends were not consistent across the districts as Nioro du Rip had a higher AF-alb level at harvest than post-harvest (80.0 vs 58.6 pg/mg, P=0.026), whereas Saint-Louis had a higher level at post-harvest than harvest (25.6 vs 15.6 pg/mg, P=0.032). It is clear that aflatoxin exposure is prevalent in adults from Senegal and that season and geographical location are strong determinants of aflatoxin exposure.

Major and trace elements in milk and Halloumi cheese as markers for authentication of goat feeding regimes and geographical origin

Sixty samples of milk, Halloumi cheese and local grazing plants (i.e. shrubs) were collected over a year from dairy farms located on three different locations of Cyprus. Major and trace elements were quantified using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Milk and Halloumi cheese produced in different geographical locations presented significant differences in the concentration of some of the elements analysed. Principal component analysis showed grouping of samples according to the region of production for both milk and cheese samples. These findings show that the assay of elements can provide useful fingerprints for the characterisation of dairy products.

Diagnostic performance on briefly presented digital pathology images

Background: Identifying new and more robust assessments of proficiency/expertise (finding new "biomarkers of expertise") in histopathology is desirable for many reasons. Advances in digital pathology permit new and innovative tests such as flash viewing tests and eye tracking and slide navigation analyses that would not be possible with a traditional microscope. The main purpose of this study was to examine the usefulness of time-restricted testing of expertise in histopathology using digital images.
Methods: 19 novices (undergraduate medical students), 18 intermediates (trainees), and 19 experts (consultants) were invited to give their opinion on 20 general histopathology cases after 1 s and 10 s viewing times. Differences in performance between groups were measured and the internal reliability of the test was calculated.
Results: There were highly significant differences in performance between the groups using the Fisher's least significant difference method for multiple comparisons. Differences between groups were consistently greater in the 10-s than the 1-s test. The Kuder-Richardson 20 internal reliability coefficients were very high for both tests: 0.905 for the 1-s test and 0.926 for the 10-s test. Consultants had levels of diagnostic accuracy of 72% at 1 s and 83% at 10 s.
Conclusions: Time-restricted tests using digital images have the potential to be extremely reliable tests of diagnostic proficiency in histopathology. A 10-s viewing test may be more reliable than a 1-s test. Over-reliance on "at a glance" diagnoses in histopathology is a potential source of medical error due to over-confidence bias and premature closure.

Emotional response to images of wind turbines: A psychophysiological study of their visual impact on the landscape

Social acceptance for wind turbines is variable, providing a challenge to the implementation of this energy source. Psychological research could contribute to the science of climate change. Here we focus on the emotional responses to the visual impact of wind turbines on the landscape, a factor which dominates attitudes towards this technology. Participants in the laboratory viewed images of turbines and other constructions (churches, pylons and power-plants) against rural scenes, and provided psychophysiological and self-report measures of their emotional reactions. We hypothesised that the emotional response to wind turbines would be more negative and intense than to control objects, and that this difference would be accentuated for turbine opponents. As predicted, the psychophysiological response to turbines was stronger than the response to churches, but did not differ from that of other industrial constructions. In contrast with predictions, turbines were rated as less aversive and more calming compared with other industrial constructions, and equivalent to churches. Supporters and non-supporters did not differ significantly from each other. We discuss how a methodology using photo manipulations and emotional self-assessments can help estimate the emotional reaction to the visual impact on the landscape at the planning stage for new wind turbine applications.