Objectives To study the effects of a one-year physical activity programme on aerobic capacity, physical activity and health-related quality of life (HRQL) in patients with systemic lupus erythematosus (SLE) by a randomized control design. Methods Thirty-five women with low or moderate disease activity and organ damage were randomized to intervention (I) or control (C) group. The intervention during months 0–3 consisted of education, supervised aerobic exercise at high intensity and individual coaching, as well as self-managed physical activity at low-to-moderate intensity. During months 4–12, the physical activity was self-managed and the coaching was successively reduced over time. Outcome measures included: maximal oxygen uptake (VO 2 max) from a bicycle ergometer test, self-reported physical activity and HRQL (SF-36). Results VO 2 at sub-max. and max. increased, independent of group, during the one-year study period (main effect of time p < 0.0001). VO 2 max. increased between baseline and month 3 ( p < 0.0001), between months 3 and 6 ( p = 0.01) and the increase was sustained at month 12 (ns). Frequency of physical activity at high intensity also increased, independent of group, during the study period. It was increased at months 3, 6 and 12 compared to baseline ( p = 0.02, p < 0.001, p = 0.03). Improvement in mental health between baseline and month 6 ( p = 0.002) was seen for the I-group, not the C-group ( p = 0.03). Disease activity and organ damage did not change. Conclusions Physical activity and aerobic capacity increased after supervised exercise and coaching, and the improvement was sustained during the one-year programme. However, no interactions between the group differences were seen, which suggests that repeated measurements could motivate to increased physical activity and thereby to increased aerobic capacity. As sub-max. VO 2 increased over time, training-induced changes in VO 2 on-kinetics could be another explanation. Little influence on HRQL was seen after the programme. The study indicates that physical activity at high intensity over one year is tolerated by patients with mild to moderate SLE.

Chemical weathering of rocks is a spontaneous (i.e., irreversible) thermodynamic process leading to a more stable state for natural materials under a given set of conditions (e.g., temperature and pressure). It results from the reaction of aqueous, acidic, and oxidizing solutions with the minerals in rocks and soils. There is no doubt that the increasing number of studies dealing with chemical weathering during recent decades is related to increasing concern about global climate change. This chapter will consider these questions. The objective is to estimate chemical weathering rates of silicates, and to define which parameters control these rates at a global scale on the basis of the chemical composition of rivers draining both small and large watersheds. The importance of parameters controlling chemical weathering rates should be evaluated and included in climate models.

In this chapter, we have tried to review the recent literature on trace elements in rivers, in particular by incorporating the results derived from recent ICP-MS measurements. We have favored a “field approach” by focusing on studies of natural hydrosystems. The basic questions which we want to address are the following: What are the trace element levels in river waters? What controls their abundance in rivers and fractionation in the weathering + transport system? Are trace elements, like major elements in rivers, essentially controlled by source-rock abundances? What do we know about the chemical speciation of trace elements in water? To what extent do colloids and interaction with solids regulate processes of trace elements in river waters? Can we relate the geochemistry of trace elements in aquatic systems to the periodic table? And finally, are we able to satisfactorily model and predict the behavior of most of the trace elements in hydrosystems?

We measured the seasonal dynamics of major and trace elements concentrations in foliage of larch, main conifer species of Siberia, and we analyzed cryogenic soils collected in typical permafrost-dominated habitats in the Central Siberia. This region offers a unique opportunity to study element fractionation between the soil and the plant because of (i) the homogeneous geological substratum, (ii) the monospecific stands ( Larix gmelinii ) and (iii) the contrasted habitats (North-facing slope, South-facing slope, and Sphagnum peatbog) in terms of soil temperature, moisture, thickness of the active layer, tree biomass and rooting depth. The variation of these parameters from one habitat to the other allowed us to test the effects of these parameters on the element concentration in larch foliage considered with high seasonal resolution. Statistical treatment of data on larch needles collected 4 times in 3 locations during entire growing season (June–September) demonstrated that : (1) there is a high similarity of foliar chemical composition of larch trees in various habitats suggesting intrinsically similar requirements of larch tree growth for nutrients, (2) the variation of elemental concentrations in larch needles is controlled by the period (within the growing season) and not by the geographical location (South-facing slope, North-facing slope or bog zone) and (3) there are three groups of elements according to their patterns of elements concentration in needles over the growing season from June to September can be identified: (1): nutrient elements [P, Cu, Rb, K, B, Na, Zn, Ni and Cd] showing a decrease of concentration from June to September similar to the behaviour of major nutrients such as N, P and K; (2): accumulating elements [Ca, Mg, Mo, Co, Sr, Mn, Pb and Cr] showing an increase of concentration from June–July to September; (3): indifferent elements [Al, Zr, Fe, Ba, Ti, REEs (Pr, Nd, Ce, La, Gd, Er, Dy, Tb, Lu, Yb, Tm, Sm, Ho, Eu), Y, Th and U] showing a decrease of concentration from June to July and then an increase of concentration to September. A number of micronutrients (e.g., Cu, Zn) demonstrate significant resorption at the end of growing season suggesting possible limitation by these elements. Although the intrinsic requirement seems to be similar among habitats, the total amount of element stored within the different habitats is drastically different due to the differences in standing tree biomass. The partitioning coefficients between soil and larch appear to be among the lowest compared to other environments with variable plants, soils and climates. Applying the “space for time” substitution scenario, it follows that under ongoing climate warming there will be an increase of the element stock following enhanced above-ground biomass accumulation, even considering zero modification of element ratios and their relative mobility. In this sense, the habitats like south-facing slopes can serve as resultant of climate warming effect on element cycling in larch ecosystems for the larger territory of Central Siberia.

This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw) lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i) document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii) characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC) stock in thermokarst lake sediments of 14 ± 2 kg m−2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM) mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions was suggested. This shift was likely promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides) and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of ecosystem development, the sediments were a source of dissolved Co, Ni and As to the water column. However, the concentrations of these trace elements remained low in the bottom waters, indicating that sorption processes on Fe-bounding particles and/or large-size organo-mineral colloids could mitigate the impact of post-depositional redistribution of toxic elements on the water column.

To examine the mechanisms of carbon mobilization and biodegradation during permafrost thawing and to establish a link between organic carbon (OC) and other chemical and microbiological parameters in forming thermokarst (thaw) lakes, we studied the biogeochemistry of OC and trace elements (TEs) in a chronosequence of small lakes that are being formed due to permafrost thawing in the northern part of western Siberia. Twenty lakes and small ponds of various sizes and ages were sampled for dissolved and colloidal organic carbon, metals and culturable heterotrophic bacterial cell number. We observed a sequence of ecosystems from peat thawing and palsa degradation due to permafrost subsidence in small ponds to large, km-size lakes that are subject to drainage to, finally, the khasyrey (drained lake) formation. There is a systematic evolution of both total dissolved and colloidal concentration of OC and TEs in the lake water along with the chronosequence of lake development that may be directly linked to the microbial mineralization of dissolved organic matter and the liberation of the inorganic components (Fe, Al, and TEs) from the organo-mineral colloids. In this chronosequence of lake development, we observed an apparent decrease in the relative proportion of low molecular weight <1 kDa (1 kDa ~ 1 nm) OC concentration along with a decrease in the concentration of total dissolved (<0.45 μm) OC. This decrease was accompanied by an increase in the small size organic ligands (probably autochthonous exometabolites produced by the phytoplankton) and a simultaneous decrease in the proportion of large-size organic (humic) complexes of allochthonous (soil) origin. This evolution may be due to the activity of heterotrophic bacterioplankton that use allochthonous organic matter and dissolved nutrients originating from peat lixiviation. Most insoluble TEs demonstrate a systematic decrease in concentration during filtration (5 μm, 0.45 μm) exhibiting a similar pattern among different samples. At the same time, there is an increase in the relative proportion of large size particles over the <1 kDa fraction for most insoluble elements along the chronosequence of lake evolution. TEs are likely to be bound to colloidal OC and coprecipitate with the mineral (Fe, Al) part of the colloids. Upon progressive consumption of dissolved OC by the heterotrophic bacteria, there is liberation of Fe, Al, and insoluble TEs in the water column that may be subjected to coagulation in the form of particles or large-size mineral colloids.

The chemical status of major and trace elements (TE) and organic carbon (OC) has been studied in the Severnaya Dvina and Pinega rivers draining granitic moraine, carbonate and sedimentary deposits of the Arkhangelsk region (NW Russia, the White Sea basin of the Arctic Ocean). Sampling was performed during winter and summer baseflow seasons and during the spring flood (2007–2008). Size separation procedure included on-site filtration through 5µm, 0.22µm, 100, 10 and 1kDa, and dialysis through 1kDa and 10kDa pore-size membranes. The organic carbon concentration in “truly” dissolved form (<1kDa) does not depend on rock lithology or season, being on average equal to 5.0±1.4mg/L. Our observations may suggest the presence of two types of organic matter pool: i) allochtonous large-size colloids formed by lixiviation from upper soil horizons and ii) autochthonous (aquatic) small molecular-size substances, probably linked to bacterial and phytoplankton exudates. The total dissolved concentration of colloidal TE correlates with OC and Fe contents, being highest during the spring flood and lowest in winter time. There are two different patterns of TE colloidal status during different periods of the year, depending on their association with the organic or organo-mineral constituents of the colloidal matter pool.

On-site size fractionation of about 40 major and trace elements (TE) was performed on waters from boreal small rivers and their estuaries in the Karelia region of North-West Russia around the "Vetreny Belt" mountain range and in Paanajarvi National Park (Northern Karelia). Samples were filtered in the field using a progressively decreasing pore size (5 mu m, 2.5 (3) mu m, 0.22 (0.45) mu m, 100 kDa, 10 and 1 kDa) by means of frontal filtration and ultrafiltration (UF) techniques and employing in-situ dialysis with 10 and I kDa membranes followed by ICP-MS analysis. For most samples, dialysis yields a systematically higher (factor of 2-3) proportion of colloidal forms compared to UF. Nevertheless, dialysis is able to provide a fast and artefact-free in-situ separation of colloidal and dissolved components.Similar to previous studies in European subarctic zones, poor correlation of iron concentration with that of organic carbon (OC) in (ultra)filtrates and dialysates reflect the presence of two pools of colloids composed of organic-rich and Fe-rich particles. All major anions and silica are present as dissolved species (or solutes) passing through the 1-kDa membrane. Size-separation ultrafiltration experiments show the existence of larger or smaller pools of colloidal particles different for each of the considered elements.The effect of rock lithology (acidic versus basic) on the colloidal speciation of TE is seen solely in the increase of Fe and some accompanying TE concentrations in catchment areas dominated by basic rocks compared to granitic catchments. Neither the ultrafiltration pattern nor the relative proportions of colloidal versus truly dissolved TE are affected by the lithology of the underlying rocks: within +/- 10% uncertainty, the two colloidal (10 kDa-0.22 mu m and 1-10 kDa) and the truly dissolved (< 1 kDa) pools show no difference in percentage of TE distribution between two types of bedrock lithology. The same conclusion is held for organic- and Fe-rich waters. In contrast, landscape context analysis demonstrated slight dominance, for most TE affected by UF, of large-size colloids (10 kDa-0.22 mu m) in rivers and streams and small-size colloids and truly dissolved fractions in swamp stagnant surface waters. This supports the existence of two pathways of colloids formation: during the plant litter degradation in wetland zones and at the redox front in river riparian zone. (c) 2009 Elsevier Ltd. All rights reserved.

This work reports on results of bacterio‐plankton characterisation in thaw lakes of the northern part of Western Siberia via measurement the number of various groups of heterotrophic bacteria and the intensity of primary production/respiration in the water column. The eutrophic systems at the beginning of lake formation (permafrost thawing) are being replaced by essentially oligotrophic systems at the final, mature stage of the lake development (khasyrey). The CO2 flux from the lake surface to the atmosphere associated with microbial degradation of organic matter (107 ± 50 t C/km2/y) is at least one order of magnitude higher than the riverine organic carbon flux. The future climate evolution in this region, consisting in rising ground temperature and precipitation increase will bring about further acceleration of dissolved organic matter degradation in the water column and amplification of CO2 release to the atmosphere.

High latitude regions are characterized by very contrasted hydrological periods, marked by (a) a very low water flow during cold period (October-May), (b) an intense spring flood in May/June and (c) an intermediate to high water flow in summer (June– September). We propose here to quantify the intensity of geochemical fluxes associated to each of these hydrological periods and to constrain their origin. For this purpose, we analysed the temporal variations of the geochemical composition of water samples (filtered at 0.22µm) collected at the outlet of the Kochechumo and the Nizhnaya Tunguska rivers in Central Siberia (Russia). These analyses, performed over two hydrological cycles (2006-2008), were completed by a study of a smaller experimental watershed within the Kochechumo watershed. Our results combining major and trace element data together with Sr and U isotope ratios show that the melting flood in May results in the input of specific insoluble and soluble element fluxes in river waters. The mobilization of organic and inorganic colloids (from surface soil horizons) accounts for the insoluble element input during the flood period. The source of the dissolved element flux is clearly distinct from the source of winter waters and also originates from the uppermost horizons of the soil-permafrost system, with slight modification during the melting flood. Indeed, melting snow and leached litter appear to be the main chemical source at the beginning of the flood event whereas the suprapermafrost flow, more affected by water-rock interactions, dominates afterwards. This latter flux also dominates the chemical composition of summer river waters. During the winter, we observe in rivers the predominance of deep underground waters possibly affected by mineral precipitation or dissolution processes.

The present aim is to investigate the relationships between aerobic capacity and disease activity, organ damage, health-related quality of life (HRQL) and physical activity in 34 women with systemic lupus erythematosus (SLE) with low-to-moderate disease activity and organ damage. Mean age was 51 (SD 10) years, disease duration 17 (SD 11) years. Aerobic capacity (maximal oxygen uptake/VO2 max) was measured with a bicycle ergometer exercise test. Overall disease activity was assessed with Systemic Lupus Activity Measure (SLAM) and the modified Systemic Lupus Erythematosus-Disease Activity Index (modified SLE-DAI), overall organ damage with the Systemic Lupus International Collaboration Clinics/American College of Rheumatology-Damage Index, [SLICC/(ACR)-DI], HRQL with the 36-item Short-form health-survey (SF-36) and physical activity with a self-assessed question. The women who were low-to-moderately physically active had 89—92% ( P ≤ 0.001) of VO2 max predicted for sedentary women. Maximal oxygen uptake (L/min, mL/min/kg) correlated to SF-36 physical function ( rs = 0.49, rs = 0.72) ( P ≤ 0.01), but not ( rs ≤ 0.25) to other HRQL scales, overall disease activity or organ damage or physical activity. The correlation between aerobic capacity and physical function and the absence of correlation between aerobic capacity and physical activity, suggest a possible disease-related factor behind the low aerobic capacity. However, with no correlation between aerobic capacity and overall disease activity and organ damage, low physical activity may contribute to the low aerobic capacity in our sample. Lupus (2008) 17, 100—104.

The capabilities of an infrared (IR) Ti:sapphire femtosecond laser (≈800 nm) to ablate and analyze geomaterials such as monazite, zircon and synthetic glass reference materials is evaluated, with emphasis on U/Pb ratio determinations useful for dating accessory minerals in rocks. We particularly discuss the influence of pulse duration (respectively 60, 200, 350, 500, 670, 830, 2000 and 3000 fs) on the internal precision (2 min ablation), reproducibility over two weeks and accuracy of quadrupole ICP-MS measurements. The best results for all these criteria are obtained when using the shortest pulse duration (60 fs). It was found that internal precision and reproducibility were improved by a factor of 3 and 4, respectively, from picosecond to 60 fs pulsewidths. Reproducibility at this pulse duration for U/Pb ratio determinations is of 2% RSD or better, depending on the material analyzed, and this ratio is accurate within this uncertainty. Lead isotopic ratios also benefit from the shortest pulsewidth. They are measured at 60 fs with a precision (<0.5% RSD) approaching the limitations of quadrupole ICP-MS. Preliminary data were also obtained using the 3rd harmonic (≈266 nm) of the Ti:sapphire fundamental wavelength and they are compared with the infrared mode. There seems to be no obvious analytical benefit to switch from IR to UV in the femtosecond laser ablation regime. Analyses of zircon 91500 with IR pulses led to better repeatability, around 0.9% (10 values, 1σ), compared to 3% for the UV pulses. The accuracy appears to be comparable for the two wavelengths.