Shallow-level migmatization of gabbros in a metamorphic contact aureole, Fuerteventura Basal Complex, Canary Islands

Migmatization of gabbroic rocks at 2-3 kbar has occurred in the metamorphic contact aureole of a mafic pluton in the Fuerteventura Basal Complex (Canary Island;). Migmatites are characterized by a dense network: of closely spaced millimetre-wide leucocratic veins with perfectly preserved igneous textures. They are all relatively enriched in Al, Na I: Sr Ba, Nb, Y and the rare earth elements compared with the unaffected country rock beyond the aureole. Migmatization under such low-pressure conditions war possible because of the unusual tectonic and magmatic contact in which ii occurred. Multiple basic intrusions associated with extrusive volcanic activity created high heat flow in a small area. Alkaline and metasomatized rocks present in the country rock of the intruding pluton were leached by high-temperature fluids during contact metamorphism. These enriched fluids then favoured partial melting of the host gabbroic rocks, and contaminated both the leucosomes and melanosomes. A transpressive tectonic setting at the time of intrusion created shearing along the contact between the intrusion and its host rock. This shearing enhanced circulation of the fluids and allowed segregation of the nea-formed melts from their restite by opening tension veins into which the melts migrated. Depending on the relative timing of melt segregation and recrystallization leucosomes range in composition from a 40-60% mixture of clinopyroxene (+/- amphibole) and plagioclase to almost pure feldspathic veins. Comparable occurrences of gabbros migmatized at low pressure are expected only at a snail scale in localized areas of high heat flow in the presence of fluids, such as in. mid-ocean ridges or ocean-islands.

Secondary contact zones and hybridizations: the case of the lesser white-toothed shrew (Crocidura suaveolens group, Soricidae)

In the present study, we analyzed 58 samples of the lesser white-toothed shrew group (Crocidura suaveolens) from eastern Europe and Turkey, where, according to previous publications, three different mitochondrial and nuclear lineages are present. We sequenced 799 bp of the nuclear BRCA1 gene and 400 bp of the mitochondrial cytochrome b gene to: (1) determine a potential contact zone between the lineages; (2) detect hybridizations and introgressions between them; and (3) comment on the level of reproductive isolation of the different lineages. We revealed two zones of hybridization in Turkey, of which the first occurred west of the Bosphorus Straits (three hybrids) and the second in Anatolia (twelve hybrids). In the latter, the nuclear markers revealed a large zone of hybridization, of approximately 600 km. It also revealed that hybrids of first, second, and later generations are present within the populations, and therefore that the reproductive isolation between the different lineages is weak.

A vertebrate reproductive system involving three ploidy levels : hybrid origin of triploids in a contact zone of diploid and tetraploid green toads (Bufo viridis subgroup)

The rise and consequences of polyploidy in vertebrates, whose origin was associated with genome duplications, may be best studied in natural diploid and polyploid populations. In a diploid/tetraploid (2n/4n) geographic contact zone of Palearctic green toads in northern Kyrgyzstan, we examine 4ns and triploids (3n) of unknown genetic composition and origins. Using mitochondrial and nuclear sequence, and nuclear microsatellite markers in 84 individuals, we show that 4n (Bufo pewzowi) are allopolyploids, with a geographically proximate 2n species (B. turanensis) being their maternal ancestor and their paternal ancestor as yet unidentified. Local 3n forms arise through hybridization. Adult 3n mature males (B. turanensis mtDNA) have 2n mothers and 4n fathers, but seem distinguishable by nuclear profiles from partly aneuploid 3n tadpoles (with B. pewzowi mtDNA). These observations suggest multiple pathways to the formation of triploids in the contact zone, involving both reciprocal origins. To explain the phenomena in the system, we favor a hypothesis where 3n males (with B. turanensis mtDNA) backcross with 4n and 2n females. Together with previous studies of a separately evolved, sexually reproducing 3n lineage, these observations reveal complex reproductive interactions among toads of different ploidy levels and multiple pathways to the evolution of polyploid lineages.

Complex contact manifolds and S1 actions

We prove rigidity and vanishing theorems for several holomorphic Euler characteristics on complex contact manifolds admitting holomorphic circle actions preserving the contact structure. Such vanishings are reminiscent of those of LeBrun and Salamon on Fano contact manifolds but under a symmetry assumption instead of a curvature condition.

Contact melting of a three-dimensional phase change material on a flat substrate

In this paper a model is developed to describe the three dimensional contact melting process of a cuboid on a heated surface. The mathematical description involves two heat equations (one in the solid and one in the melt), the Navier-Stokes equations for the flow in the melt, a Stefan condition at the phase change interface and a force balance between the weight of the solid and the countering pressure in the melt. In the solid an optimised heat balance integral method is used to approximate the temperature. In the liquid the small aspect ratio allows the Navier-Stokes and heat equations to be simplified considerably so that the liquid pressure may be determined using an igenfunction expansion and finally the problem is reduced to solving three first order ordinary differential equations. Results are presented showing the evolution of the melting process. Further reductions to the system are made to provide simple guidelines concerning the process. Comparison of the solutions with experimental data on the melting of n-octadecane shows excellent agreement.

Microgeographical patterns of schistosomiasis and water contact behavior; examples from Africa and Brazil

This paper examines the results of spatial (microgeographical) water contact/schistosomiasis studies in two African (Egyptian and Kenyan) and one Brazilian communities. All three studies used traditional cartographic and statistical methods but one of them emploeyd also GIS (geographical information systems) tools. The advantage of GIS and their potential role in schistosomiasis control are briefly described. The three cases revealed considerable variation in the spatial distribution of water contact, transmission parameters and infection levels at the household and individual levels. All studies showed considerable variation in the prevalence and intensity of infection between households. They also show a variable influence of distance on water contact behavior associated with type of activity, age, sex, socioeconomic level, perception of water quality, season and availability of water in the home. Water contact behavior and schistosomiasis were evaluated in the Brazilian village of Nova União within the context of water sharing between household and age/sex groups. Recommendations are made for further spatial studies on the transmission and control of schistosomiasis.

Contact and communication with healthcare providers regarding influenza vaccination during the 2009-2010 H1N1 pandemic.

Objective. The existence of two vaccines seasonal and pandemic-created the potential for confusion and misinformation among consumers during the 2009-2010 vaccination season. We measured the frequency and nature of influenza vaccination communication between healthcare providers and adults for both seasonal and 2009 influenza A(H1N1) vaccination and quantified its association with uptake of the two vaccines.Methods. We analyzed data from 4040 U.S. adult members of a nationally representative online panel surveyed between March 4th and March 24th, 2010. We estimated prevalence rates and adjusted associations between vaccine uptake and vaccination-related communication between patients and healthcare providers using bivariate probit models.Results. 64.1% (95%-CI: 61.5%-66.6%) of adults did not receive any provider-issued influenza vaccination recommendation. Adults who received a provider-issued vaccination recommendation were 14.1 (95%-CI: -2.4 to 30.6) to 32.1 (95%-CI: 24.3-39.8) percentage points more likely to be vaccinated for influenza than adults without a provider recommendation, after adjusting for other characteristics associated with vaccination.Conclusions. Influenza vaccination communication between healthcare providers and adults was relatively uncommon during the 2009-2010 pandemic. Increased communication could significantly enhance influenza vaccination rates. (C) 2011 Elsevier Inc. All rights reserved.

Potential exposure to hepatitis C virus through accidental blood contact in interventional radiology.

PURPOSE: To quantify the prevalence of accidental blood exposure (ABE) among interventional radiologists and contrast that with the prevalence of patients with hepatitis C virus (HCV) undergoing interventional radiology procedures. MATERIALS AND METHODS: A multicenter epidemiologic study was conducted in radiology wards in France. The risk of ABE to radiologists was assessed based on personal interviews that determined the frequency and type of ABE and the use of standard protective barriers. Patients who underwent invasive procedures underwent prospective sampling for HCV serologic analysis. HCV viremia was measured in patients who tested positive for HCV. RESULTS: Of the 77 radiologists who participated in 11 interventional radiology wards, 44% reported at least one incident of mucous membrane blood exposure and 52% reported at least one percutaneous injury since the beginning of their occupational activity. Compliance with standard precautions was poor, especially for the use of protective clothes and safety material. Overall, 91 of 944 treated patients (9.7%) tested positive for HCV during the study period, of whom 90.1% had positive viremia results, demonstrating a high potential for contamination through blood contacts. CONCLUSIONS: The probability of HCV transmission from contact with contaminated blood after percutaneous injury ranged from 0.013 to 0.030; the high frequency of accidental blood exposure and high percentage of patients with HCV could generate a risk of exposure to HCV for radiologists who perform invasive procedures with frequent blood contact. The need to reinforce compliance with standard hygiene precautions is becoming crucial for medical and technical personnel working in these wards.

Patterns of sex work contact among men in the general population of Switzerland, 1987-2000

OBJECTIVES: To analyse the prevalence of lifetime recourse to prostitution (LRP) among men in the general population of Switzerland from a trend and cohort perspective. METHODS: Using nine repeated representative cross-sectional surveys from 1987 to 2000, age-specific estimates of LRP were computed. Trends and period effect were analysed as the evolution of cross-sectional population estimates within age groups and overall. Cohort analysis relied on cohorts constructed from the 1989 survey and followed in subsequent waves. Age and cohort effects were modelled using logistic regression and non-parametric monotone regression. RESULTS: Whereas prevalence for the younger groups was found to be logically lower, there was no consistent increasing or decreasing trend over the years; there was no significant period effect. For the 17-30 year age group, the mean estimate over 1987-2000 was 11.5% (range 8.3 to 12.7%); for the 31-45 year group, the mean was 21.5% (range over 1989-2000 20.3 to 23.0%). Regarding cohort analysis, the prevalence of LRP was found to increase steeply in the youngest ages before reaching a plateau near the age of 40 years. At the age of 43 years, the prevalence was estimated to be 22.6% (95% CI 21.1% to 24.1%). CONCLUSIONS: The steep increase in the cohort-wise prevalence of LRP in younger ages calls for a concentration of prevention activities in young people. If the plateauing at approximately 40 years of age is not followed by a further increase later in life, which is not known, then consumers of paid sex would be repeat buyers only, a fact that should be taken into account by prevention.

The Implamentation and Evaluation of a Framework Supporting Effective First Contact Care across the Southern Health & Social Services Board (PDF 278 KB)

Interim report on the Southern Health and Social Services Board's Community Nursing Strategy Pilot Project

Risk factors for positive tuberculin skin tests among migrant and resident children in Lausanne, Switzerland.

SETTING: Ambulatory paediatric clinic in Lausanne, Switzerland, a country with a significant proportion of tuberculosis (TB) among immigrants. AIM: To assess the factors associated with positive tuberculin skin tests (TST) among children examined during a health check-up or during TB contact tracing, notably the influence of BCG vaccination (Bacille Calmette Guérin) and history of TB contact. METHOD: A descriptive study of children who had a TST (2 Units RT23) between November 2002 and April 2004. Age, sex, history of TB contact, BCG vaccination status, country of origin and birth outside Switzerland were recorded. RESULTS: Of 234 children, 176 (75%) had a reaction equal to zero and 31 (13%) tested positive (>10 mm). In a linear regression model, the size of the TST varied significantly according to the history of TB contact, age, TB incidence in the country of origin and BCG vaccination status but not according to sex or birth in or outside Switzerland. In a logistic regression model including all the recorded variables, age (Odds Ratio = 1.21, 95% CI 1.08; 1.35), a history of TB contact (OR = 7.31, 95% CI 2.23; 24) and the incidence of TB in the country of origin (OR = 1.01, 95% CI 1.00; 1.02) were significantly associated with a positive TST but sex (OR = 1.18, 95% CI 0.50; 2.78) and BCG vaccination status (OR = 2.97, 95% CI 0.91; 9.72) were not associated. CONCLUSIONS: TB incidence in the country of origin, BCG vaccination and age influence the TSTreaction (size or proportion of TST > or = 10 mm). However the most obvious risk factor for a positive TST is a history of contact with TB.

Low-pressure, water-assisted anatexis of basic dykes in a contact metamorphic aureole, Fuerteventura (Canary Islands): oxygen isotope evidence for a meteoric fluid origin

Migmatites produced by low-pressure anatexis of basic dykes are found in a contact metamorphic aureole around a pyroxenite-gabbro intrusion (PX2), on Fuerteventura. Dykes outside and inside the aureole record interaction with meteoric water, with low or negative delta O-18 whole-rock values (+0.2 to -3.4 parts per thousand), decreasing towards the contact. Recrystallised plagioclase, diopside, biotite and oxides, from within the aureole, show a similar evolution with lowest delta O-18 values (-2.8, -4.2, - 4.4 and -7.6 parts per thousand, respectively) in the migmatite zone, close to the intrusion. Relict clinopyroxene phenocrysts preserved in all dykes, retain typically magmatic delta O-18 values up to the anatectic zone, where the values are lower and more heterogeneous. Low delta O-18 values, decreasing towards the intrusion, can be ascribed to the advection of meteoric water during magma emplacement, with increasing fluid/rock ratios (higher dyke intensities towards the intrusion acting as fluid-pathways) and higher temperatures promoting increasing exchange during recrystallisation.