Seven years of gamma-ray spectrometry interlaboratory comparisons in Switzerland.

Since the 1990s, regular comparisons of gamma-ray spectrometry in Switzerland were organized to improve laboratory abilities to measure the radioactivity in the environment and food stuffs at typical routine levels. The activity concentration of the test samples and the evaluation of the associated uncertainties remained each year the main required test result. Over the years, the comparisons used certified reference solutions as well as environmental samples. The aim of this study is to research the effect of the comparisons on measurement quality. An analysis of the seven last interlaboratory comparisons revealed that the Swiss measurement capability is up to date. In addition, the results showed that the participants now have an improved evaluation of the uncertainties associated with their measurement.

Garnet growth in the Nufenen Pass area (Swiss Alps)

Abstract : Textural division of a mineral in pyramids, with their apices located at the centre of the mineral and their bases corresponding to the mineral faces is called textural sector zoning. Textural sector zoning is observed in many metamorphic minerals like andalousite and garnet. Garnets found in the graphite rich black shales of the Mesozoic cover of the Gotthard Massif display textural sector zoning. The morphology of this sector zoning is not the same in different types of black shales observed in the Nufenen pass area. Garnets in foliated black shales display a well developed sector zoning while garnets found in cm-scale layered black shales display well developed sectors in the direction of the schistosity plane. This sector zoning is always associated with up to 30μm sized birefringent lamellae emanating radial from the sector boundaries. They alternate with isotrope lamellae. The garnet forming reaction was determined using singular value decomposition approach and results compared to thermodynamic calculations. It is of the form chl + mu + cc + cld = bt + fds + ank + gt + czo and is similar in both layered and foliated black shales. The calculated X(O) is close to 0.36 and does not significantly vary during the metamorphic history of the rock. This corresponds to X CO2, X CH4, and X H2O BSE imaging of garnets on oriented-cuts revealed that the orientation of the lamellae found within the sectors is controlled by crystallography. BSE imaging and electron microprobe analysis revealed that these lamellae are calcium rich compared to the isotropic lamellae. The addition of Ca to an almandine rich garnet causes a small distortion of the X site and potentially, ordering. Ordered and disordered garnet might have very similar free energies for this composition. Hence, two garnets with different composition can be precipitated with minor overstepping of the reaction. It is enough that continued nucleation of a new garnet layer slightly prefers the same structure to assure a fiber-like growth of both garnet compositions side by side. This hypothesis is in agreement with the thermodynamic properties of the garnet solid solution described in the literature and could explain the textures observed in garnets with these compositions. To understand the differences in sector zoning morphology, and crystal growth kinetics, crystal size distribution were determined in several samples using 2D spatial analysis of slab surfaces. The same nucleation rate law was chosen for all cases. Different growth rate law for non-layered black shales and layered black shales were used. Garnet in layered black shales grew according to a growth rate law of the form R=kt ½. The transport of nutrient is the limiting factor. Transport will occur preferentially on the schistosity planes. The shapes of the garnets in such rocks are therefore ovoid with the longest axis parallel to the schistosity planes. Sector zoning is less developed with sectors present only parallel to the schistosity planes. Garnet in non-layered blackshales grew according to a growth rate law of the form R=kt. The limiting factor is the attachment at the surface of the garnet. Garnets in these rocks will display a well developed sector zoning in all directions. The growth rate law is thus influenced by the texture of the rock. It favours or hinders the transport of nutrient to the mineral surface. Résumé : La zonation sectorielle texturale consiste en la division d'un cristal en pyramides dont les sommets sont localisés au centre du minéral. La base de ces pyramides correspond aux faces du minéral. Ce type de zonation est fréquemment observé dans les minéraux métamorphiques tels que l'andalousite ou le grenat. Les grenats présents dans les marnes riches en graphites de la couverture Mésozoïque du Massif du Gotthard présent une zonation sectorielle texturale. La morphologie de cette zonation n'est pas la même dans les marnes litées et dans les marnes foliées. Les grenats des marnes foliées montrent des secteurs bien développés dans 3 directions. Les grenats des marnes litées montrent des secteurs développés uniquement dans la direction des plans de schistosité. Cette zonation sectorielle est toujours associée à des lamelles biréfringentes de quelques microns de large qui partent de la limite des secteurs et qui sont perpendiculaires aux faces du grenat. Ces lamelles alternent avec des lamelles isotropes. La réaction de formation du grenat a été déterminée par calcul matriciel et thermodynamique. La réaction est de la forme chl + mu + cc + cld= bt + fds + ank + gt + czo. Elle est similaire dans les roches litées et dans les roches foliées. L'évaluation des conditions fluides montrent que le X(O) est proche de 0.36 et ne change pas de façon significative durant l'histoire métamorphique de la roche. Des images BSE sur des coupes orientées ont révélé que l'orientation de lamelles biréfringentes est contrôlée parla crystallographie. La comparaison des analyses à la microsonde électronique et des images BSE révèle également que les lamelles biréfringentes sont plus riches en calcium que les lamelles isotropes. L'addition de calcium va déformer légèrement le site X et ainsi créer un ordre sur ce site. L'énergie interne d'un grenat ordré et d'un grenat désordonné sont suffisamment proches pour qu'un léger dépassement de l'énergie de la réaction de formation permette la coexistence des 2 types de grenat dans le même minéral. La formation de lamelles est expliquée par le fait qu'un grenat préférera la même structure. Ces observations sont en accord avec la thermodynamique des solutions solides du grenat et permet d'expliquer les structures similaires observées dans des grenats provenant de lithologies différentes. Une étude de la distribution des tailles des grenats et une modélisation de la croissance a permis de mettre en évidence 2 mécanismes de croissance différents suivant la texture de la roche. Dans les 2 cas, la loi de nucléation est la même. Dans les roches litées, la loi de croissance est de forme R=kt½. Le transport des nutriments est le facteur limitant. Ce transport a lieu préférentiellement dans la direction des niveaux de schistosité. Les grenats ont une forme légèrement allongée car la croissance des secteurs est facilitée sur les niveaux de schistosité. La croissance des grenats dans les roches foliées suit une loi de croissance de la forme R=kt. Les seuls facteurs limitant la croissance sont les processus d'attachement à la surface du grenat. La loi de croissance de ces grenats est donc contrainte par la texture de la roche. Cela se marque par des différences dans la morphologie de la zonation sectorielle.

Device-specific weighted T-score for two quantitative ultrasounds: operational propositions for the management of osteoporosis for 65 years and older women in Switzerland.

The World Health Organization (WHO) criteria for the diagnosis of osteoporosis are mainly applicable for dual X-ray absorptiometry (DXA) measurements at the spine and hip levels. There is a growing demand for cheaper devices, free of ionizing radiation such as promising quantitative ultrasound (QUS). In common with many other countries, QUS measurements are increasingly used in Switzerland without adequate clinical guidelines. The T-score approach developed for DXA cannot be applied to QUS, although well-conducted prospective studies have shown that ultrasound could be a valuable predictor of fracture risk. As a consequence, an expert committee named the Swiss Quality Assurance Project (SQAP, for which the main mission is the establishment of quality assurance procedures for DXA and QUS in Switzerland) was mandated by the Swiss Association Against Osteoporosis (ASCO) in 2000 to propose operational clinical recommendations for the use of QUS in the management of osteoporosis for two QUS devices sold in Switzerland. Device-specific weighted "T-score" based on the risk of osteoporotic hip fractures as well as on the prediction of DXA osteoporosis at the hip, according to the WHO definition of osteoporosis, were calculated for the Achilles (Lunar, General Electric, Madison, Wis.) and Sahara (Hologic, Waltham, Mass.) ultrasound devices. Several studies (totaling a few thousand subjects) were used to calculate age-adjusted odd ratios (OR) and area under the receiver operating curve (AUC) for the prediction of osteoporotic fracture (taking into account a weighting score depending on the design of the study involved in the calculation). The ORs were 2.4 (1.9-3.2) and AUC 0.72 (0.66-0.77), respectively, for the Achilles, and 2.3 (1.7-3.1) and 0.75 (0.68-0.82), respectively, for the Sahara device. To translate risk estimates into thresholds for clinical application, 90% sensitivity was used to define low fracture and low osteoporosis risk, and a specificity of 80% was used to define subjects as being at high risk of fracture or having osteoporosis at the hip. From the combination of the fracture model with the hip DXA osteoporotic model, we found a T-score threshold of -1.2 and -2.5 for the stiffness (Achilles) determining, respectively, the low- and high-risk subjects. Similarly, we found a T-score at -1.0 and -2.2 for the QUI index (Sahara). Then a screening strategy combining QUS, DXA, and clinical factors for the identification of women needing treatment was proposed. The application of this approach will help to minimize the inappropriate use of QUS from which the whole field currently suffers.

Prevalence and factors associated with difficulty and intention to quit smoking in Switzerland.

ABSTRACT: BACKGROUND: Recent data indicate a slight decrease in the prevalence of smoking in Switzerland, but little is known regarding the intention and difficulty to quit smoking among current smokers. Hence, we aimed to quantify the difficulty and intention to quit smoking among current smokers in Switzerland. METHODS: Cross-sectional study including 607 female and 658 male smokers. Difficulty, intention and motivation to quit smoking were assessed by questionnaire. RESULTS: 90% of women and 85% of men reported being "very difficult" or "difficult" to quit smoking. Almost three quarters of smokers (73% of women and 71% of men) intended to quit; however, less than 20% of them were in the preparation stage and 40% were in the precontemplation stage. On multivariate analysis, difficulty to quit was lower among men (Odds ratio and 95% [confidence interval]: 0.51 [0.35-0.74]) and increased with nicotine dependence and number of previous quitting attempts (OR=3.14 [1.75-5.63] for 6+ attempts compared to none). Intention to quit decreased with increasing age (OR=0.48 [0.30-0.75] for [greater than or equal to]65 years compared to <45 years) and increased with nicotine dependence, the number of previous quitting attempts (OR=4.35 [2.76-6.83] for 6+ attempts compared to none) and among non-cigarette smokers (OR=0.51 [0.28-0.92]). Motivation to quit was inversely associated with nicotine dependence and positively associated with the number of previous quitting attempts and personal history of lung disease. CONCLUSION: Over two thirds of Swiss smokers want to quit. However, only a small fraction wishes to do so in the short term. Nicotine dependence, previous attempts to quit or previous history of lung disease are independently associated with difficulty and intention to quit.

HIV-1 drug resistance transmission networks in southwest Switzerland.

To determine viral subtypes and resistance mutations to antiretroviral treatment (ART) in untreated HIV-1 acutely infected subjects from Southwest Switzerland. Clinical samples were obtained from the HIV primary infection cohort from Lausanne. Briefly, pol gene was amplified by nested PCR and sequenced to generate a 1?kb sequence spanning protease and reverse transcriptase key protein regions. Nucleotide sequences were used to assess viral genotype and ART resistance mutations. Blood specimens and medical information were obtained from 30 patients. Main viral subtypes corresponded to clade B, CRF02_AG, and F1. Resistant mutations to PIs consisted of L10V and accessory mutations 16E and 60E present in all F1 clades. The NNRTI major resistant mutation 103N was detected in all F1 viruses and in other 2 clades. Additionally, we identified F1 sequences from other 6 HIV infected and untreated individuals from Southwest Switzerland, harboring nucleotide motifs and resistance mutations to ART as observed in the F1 strains from the cohort. These data reveal a high transmission rate (16.6%) for NNRTI resistant mutation 103N in a cohort of HIV acute infection. Three of the 5 resistant strains were F1 clades closely related to other F1 isolates from HIV-1 infection untreated patients also coming from Southwest Switzerland. Overall, we provide strong evidence towards an HIV-1 resistant transmission network in Southwest Switzerland. These findings have relevant implications for the local molecular mapping of HIV-1 and future ART surveillance studies in the region.

Cardiovascular risk estimation and eligibility for statin therapy using different scoring systems in Europe: a population-based study in Switzerland

BACKGROUND: Recommendations for statin use for primary prevention of coronary heart disease (CHD) are based on estimation of the 10- year CHD risk. We compared the 10-year CHD risk assessments and eligibility percentages for statin therapy using three scoring algorithms currently used in Europe. METHODS: We studied 5683 women and men, aged 35-75, without overt cardiovascular disease (CVD), in a population-based study in Switzerland. We compared the 10-year CHD risk using three scoring schemes, i.e., the Framingham risk score (FRS) from the U.S. National Cholesterol Education Program's Adult Treatment Panel III (ATP III), the PROCAM scoring scheme from the International Atherosclerosis Society (IAS), and the European risk SCORE for low-risk countries, without and with extrapolation to 60 years as recommended by the European Society of Cardiology guidelines (ESC). With FRS and PROCAM, high-risk was defined as a 10- year risk of fatal or non-fatal CHD>20% and a 10-year risk of fatal CVD≥5% with SCORE. We compared the proportions of high-risk participants and eligibility for statin use according to these three schemes. For each guideline, we estimated the impact of increased statin use from current partial compliance to full compliance on potential CHD deaths averted over 10 years, using a success proportion of 27% for statins. RESULTS: Participants classified at high-risk (both genders) were 5.8% according to FRS and 3.0% to the PROCAM, whereas the European risk SCORE classified 12.5% at high-risk (15.4% with extrapolation to 60 years). For the primary prevention of CHD, 18.5% of participants were eligible for statin therapy using ATP III, 16.6% using IAS, and 10.3% using ESC (13.0% with extrapolation) because ESC guidelines recommend statin therapy only in high-risk subjects. In comparison with IAS, agreement to identify eligible adults for statins was good with ATP III, but moderate with ESC. Using a population perspective, a full compliance with ATP III guidelines would reduce up to 17.9% of the 24′ 310 CHD deaths expected over 10 years in Switzerland, 17.3% with IAS and 10.8% with ESC (11.5% with extrapolation). CONCLUSIONS: Full compliance with guidelines for statin therapy would result in substantial health benefits, but proportions of high-risk adults and eligible adults for statin use varied substantially depending on the scoring systems and corresponding guidelines used for estimating CHD risk in Europe.

"Public on the outside, private on the inside": the organizational hybridization, sense of belonging and identity strategies of the employees of a public unemployment insurance fund in Switzerland

A number of studies show that New Public Management reforms have altered the current identity benchmarks of public officials, particularly by hybridizing values or management practices. However, existing studies have largely glossed over the sense of belonging of officials when their organization straddles the concerns of public service and private enterprise, so that the boundary between public and private sector is blurred. The purpose of this article is precisely to explore this sense of belonging in the context of organizational hybridization. It does so by drawing on the results of research conducted among the employees of a public unemployment insurance fund in Switzerland. On the one hand, the analysis shows how much their markers of belonging are hybrid, multiple and constructed in negative terms (with regard to the State), while indicating that the working practices of the employees point to an identity that is nevertheless closely bound with the public sector. On the other hand, the analysis shows that the organization plays strategically with its State status, by exploiting either its private or public identity in line with the needs related to its external image. The article concludes with a discussion of the results highlighting the strategic functionality of the hybrid identity of the actors.

The newly defined "Greenstone Unit'' of the Aiguilles Rouges massif (western Alps): remnant of an Early Palaeozoic oceanic island-arc ?

In the southwestern part of the Aiguilles Rouges massif (pre-Alpine basement of the Helvetic realm, western Alps), a metavolcanic sequence, newly defined as the ``Greenstone Unit'',is exposed in two NS trending belts of several 100 metres in thickness. It consists of epidote amphibolites, partly epidote and/or calcic amphibole-bearing greenschists, and small amounts of alkali feldspar-bearing greenschists, which underwent low- to medium-grade metamorphism during Visean oblique collision. Metamorphic calcic amphiboles and epidotes show strong chemical zoning, whereas metamorphic plagioclase is exclusively albitic in composition (An 1-3). The SiO2 content of the subalkaline tholeiitic to calc-alkaline suite ranges continuously from 44 wt% to 73 wt%,but andesitic rocks predominate. The majority of samples have chemical compositions close to recent subduction-related lavas; some are even restricted to recent oceanic arcs (extremely low Ta and Nb contents, high La/Nb and Th/Ta ratios). But several basaltic to basalto-andesitic samples resemble continental tholeiites (low Th/Ta, La/Nb ratio). As it is very probable that both lava types are to some extent contemporaneous, it is proposed that the Greenstone Unit represents a former oceanic volcanic are which temporarily underwent extension during which emplacement of continental tholeiite-like rocks occurred. The cause of the extension remains ambiguous. Considering palaeotectonic significance and age of other metavolcanic units in the Aiguilles Rouges massif, the Greenstone Unit most likely formed in the Early Palaeozoic.

Impact of international consensus guidelines on antiviral therapy of chronic hepatitis C patients in Switzerland.

To assess the impact of international consensus conference guidelines on the attitude of Swiss specialists when facing the decision to treat chronic hepatitis C patients. Questionnaires focusing on the personal situation and treatment decisions were mailed to 165 patients who were newly diagnosed with hepatitis C virus (HCV) infection and enrolled into the Swiss Hepatitis C Cohort Study during the years 2002-2004. Survey respondents (n = 86, 52.1%) were comparable to non-respondents with respect to severity of liver disease, history of substance abuse and psychiatric co-morbidities. Seventy percent of survey respondents reported having been offered antiviral treatment. Patients deferred from treatment had less advanced liver fibrosis, were more frequently infected with HCV genotypes 1 or 4 and presented more often with a history of depression. There were no differences regarding age, socio-economic background, alcohol abuse, intravenous drug abuse or methadone treatment when compared with patients to whom treatment was proposed. Ninety percent of eligible patients agreed to undergo treatment. Overall, 54.6% of respondents and 78.3% of those considered eligible had actually received antiviral therapy by 2007. Ninety-five percent of patients reported high satisfaction with their own hepatitis C management. Consistent with latest international consensus guidelines, patients enrolled in the Swiss Hepatitis C Cohort with a history of substance abuse were not withheld antiviral treatment. A multidisciplinary approach is warranted to provide antiviral treatment to patients suffering from depression.

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.