Tracing of the Rhône River, wastewater, and mixing within Lake Geneva : stable isotope compositions of water and dissolved inorganic carbon

This study presents an evaluation of the stable isotopic composition of water (hydrogen and oxygen) and dissolved inorganic carbon (DIC) of Lake Geneva, a deep, peri-alpine lake situated at the border between Switzerland and France. The research goal is to apply vertical and seasonal variations of the isotope compositions to evaluate mixing processes of pollutants, nutrients and oxygen. Depth profiles were sampled at different locations throughout Lake Geneva on a monthly and seasonal basis over the course of three years (2009-2011). The results of the oxygen isotopic composition indicate a Rhône River interflow, which can be traced for about 55 km throughout the lake during summer. The Rhône River interflow is 7 to 15 m thick and the molar fraction of Rhône water is estimated to amount up to 37 %. Calculated density of the water and measured isotopic compositions demonstrate that the interflow depth changes in conjunction with the density gradient in the water column during fall. Partial pressure of CO2 indicates that the epilimnion is taking up CO2 from the atmosphere between spring and fall. The epilimnion is most enriched in 13CDIC in September and a progressive depletion of 13CDIC can be observed in the metalimnion from spring to late fall. This stratification is dependent on the local density stratification and the results demonstrate that parameters, which are indicating photosynthesis, are not necessarily linked to δ13CDIC values. In addition, the amount of primary production shows a strong discrepancy between summer 2009 and 2010, but δ13CDIC values of the epilimnion and metalimnion do not indicate variations. In the hypolimnion of the deep lake δ13CDIC values are constant and the progressive depletion allows tracing remineralization processes. The combination of stable carbon and oxygen isotopic compositions allows furthermore tracing Rhône River water fractions, as well as wastewater, stormwater and anthropogenic induced carbon in the water column of the shallow Bay of Vidy. In combination with the results of measured micropollutants, the study underlines that concentrations of certain substances may be related to the Rhône River interflow and/or remineralization of particulate organic carbon. Water quality monitoring and research should therefore be extended to the metalimnion as well as sediment water interface.

Treatment intensification and risk factor control: toward more clinically relevant quality measures.

BACKGROUND: Intensification of pharmacotherapy in persons with poorly controlled chronic conditions has been proposed as a clinically meaningful process measure of quality. OBJECTIVE: To validate measures of treatment intensification by evaluating their associations with subsequent control in hypertension, hyperlipidemia, and diabetes mellitus across 35 medical facility populations in Kaiser Permanente, Northern California. DESIGN: Hierarchical analyses of associations of improvements in facility-level treatment intensification rates from 2001 to 2003 with patient-level risk factor levels at the end of 2003. PATIENTS: Members (515,072 and 626,130; age >20 years) with hypertension, hyperlipidemia, and/or diabetes mellitus in 2001 and 2003, respectively. MEASUREMENTS: Treatment intensification for each risk factor defined as an increase in number of drug classes prescribed, of dosage for at least 1 drug, or switching to a drug from another class within 3 months of observed poor risk factor control. RESULTS: Facility-level improvements in treatment intensification rates between 2001 and 2003 were strongly associated with greater likelihood of being in control at the end of 2003 (P < or = 0.05 for each risk factor) after adjustment for patient- and facility-level covariates. Compared with facility rankings based solely on control, addition of percentages of poorly controlled patients who received treatment intensification changed 2003 rankings substantially: 14%, 51%, and 29% of the facilities changed ranks by 5 or more positions for hypertension, hyperlipidemia, and diabetes, respectively. CONCLUSIONS: Treatment intensification is tightly linked to improved control. Thus, it deserves consideration as a process measure for motivating quality improvement and possibly for measuring clinical performance.

Age and gender variations of sleep in subjects without sleep disorders.

OBJECTIVE: Although sleep is a biomarker for general health and pathological conditions, its changes across age and gender are poorly understood. METHODS: Subjective evaluation of sleep was assessed by questionnaires in 5,064 subjects, and 2,966 were considered without sleep disorders. Objective evaluation was performed by polysomnography in 2,160 subjects, and 1,147 were considered without sleep disorders. Only subjects without sleep disorders were included (aged 40-80 years). RESULTS: Aging was strongly associated with morning preference. Older subjects, especially women, complained less about sleepiness, and pathological sleepiness was significantly lower than in younger subjects. Self-reported sleep quality and daytime functioning improved with aging. Sleep latency increased with age in women, while sleep efficiency decreased with age in both genders. Deep slow-wave sleep decreased with age, but men were more affected. Spectral power densities within slow waves (< 5 Hz) and fast spindles (14-14.75 Hz) decreased, while theta-alpha (5-1 Hz) and beta (16.75-25 Hz) power in non-rapid eye movement sleep increased with aging. In REM sleep, aging was associated with a progressive decrease in delta (1.25-4.5 Hz) and increase in higher frequencies. CONCLUSIONS: Our findings indicate that sleep complaints should not be viewed as part of normal aging but should prompt the identification of underlying causes.

Complexity of the Paradigms Present in Quality Criteria of Qualitative Research Grids

With qualitative methods being increasingly used in health science fields, numerous grids proposing criteria to evaluate the quality of this type of research have been produced. Expert evaluators deem that there is a lack of consensual tools to evaluate qualitative research. Based on the review of 133 quality criteria grids for qualitative research in health sciences, the authors present the results of a computerized lexicometric analysis, which confirms the variety of intra- and inter-grid constructions, including within the same field. This variety is linked to the authors' paradigmatic references underlying the criteria proposed. These references seem to be built intuitively, reflecting internal representations of qualitative research, thus making the grids and their criteria hard to compare. Consequently, the consensus on the definitions and the number of criteria becomes problematic. The paradigmatic and theoretical references of the grids should be specified so that users could better assess their contributions and limitations.