Shifts in species and phylogenetic diversity between sapling and tree communities indicate negative density dependence in a lowland rain forest

1. As trees in a given cohort progress through ontogeny, many individuals die. This risk of mortality is unevenly distributed across species because of many processes such as habitat filtering, interspecific competition and negative density dependence. Here, we predict and test the patterns that such ecological processes should inscribe on both species and phylogenetic diversity as plants recruit from saplings to the canopy. 2. We compared species and phylogenetic diversity of sapling and tree communities at two sites in French Guiana. We surveyed 2084 adult trees in four 1-ha tree plots and 943 saplings in sixteen 16-m2 subplots nested within the tree plots. Species diversity was measured using Fisher's alpha (species richness) and Simpson's index (species evenness). Phylogenetic diversity was measured using Faith's phylogenetic diversity (phylogenetic richness) and Rao's quadratic entropy index (phylogenetic evenness). The phylogenetic diversity indices were inferred using four phylogenetic hypotheses: two based on rbcLa plastid DNA sequences obtained from the inventoried individuals with different branch lengths, a global phylogeny available from the Angiosperm Phylogeny Group, and a combination of both. 3. Taxonomic identification of the saplings was performed by combining morphological and DNA barcoding techniques using three plant DNA barcodes (psbA-trnH, rpoC1 and rbcLa). DNA barcoding enabled us to increase species assignment and to assign unidentified saplings to molecular operational taxonomic units. 4. Species richness was similar between saplings and trees, but in about half of our comparisons, species evenness was higher in trees than in saplings. This suggests that negative density dependence plays an important role during the sapling-to-tree transition. 5. Phylogenetic richness increased between saplings and trees in about half of the comparisons. Phylogenetic evenness increased significantly between saplings and trees in a few cases (4 out of 16) and only with the most resolved phylogeny. These results suggest that negative density dependence operates largely independently of the phylogenetic structure of communities. 6. Synthesis. By contrasting species richness and evenness across size classes, we suggest that negative density dependence drives shifts in composition during the sapling-to-tree transition. In addition, we found little evidence for a change in phylogenetic diversity across age classes, suggesting that the observed patterns are not phylogenetically constrained.

Water chemistry and isotope composition of the Acquarossa thermal system, Ticino, Switzerland

The thermal springs of Acquarossa and the nearby mineral springs of Soia have outlet temperatures of 12 degrees to 25 degrees C, TDS of 2290 to 3000 mg/kg and Ca-SO4 to Ca-SO4-HCO3 composition. Chemical geothermometers suggest reservoir temperatures close to 60 degrees C. P-CO2 values at depth are estimated to range from 0.3 to 2 bar. delta D and delta(18)O values indicate a meteoric origin and recharge elevations of 1600 +/- 150 m above sea level (a.s.l.) for these thermal and mineral waters. All these waters discharge from the overturned limb of the Simano nappe, probably dose to the contact between basement and underlying cover rocks. They therefore represent rain waters that descend slowly, heat at depth and locally rise relatively quickly to the surface, preserving part of their physical and chemical characteristics. (C) 1999 CNR. Published by Elsevier Science Ltd. All rights reserved.

Stable O and H isotopic composition of hydrous minerals as proxies for paleoclimate and -topography : application to the European Alps

The isotopie composition of clay minerals can be used to gain information on paleoaltitude, -topography and -climate during the time of their formation, as they form in isotopie equilibrium with ambient water, which has an isotopie composition that is determined by previous rain-out. In this thesis, the usability of this approach is evaluated for sample material from both the North Alpine Foreland Basin and internal parts of the European Alps. The isotopie composition of precipitation is determined by the air temperature and the extent of previous rain-out, which in turn is affected by the distance to the point of origin of the water vapor and the condensation conditions. An orographic barrier leads to uplift and adiabatic cooling of air masses and thereby enhances rainfall with a characteristic depletion in heavy 0 and H isotopes. Processes such as evaporation and mixing of water with different origin affect the isotopie composition further on the surface. Clay minerals are hydrous phyllosilicates that can form during weathering or pedogenesis in isotopie equilibrium with the present water and inherit its isotopie composition with a characteristic fractionation. If their isotopie composition was preserved after formation and the necessary parameters are known, it is possible to calculate the isotopie composition of the ambient water and thereby reconstruct climatic and topographic conditions during their formation. Due to the hygroscopic behavior of the sample material, analytical procedures needed to be modified to allow an analysis of the oxygen and hydrogen isotopie composition of the hydroxyl water built into their crystal structure and not the one of recently adsorbed water. In order to determine typical 5lsO and 8D values of meteoric water and minerals in the weathering environment in high Alpine regions, samples of surface water and soils from the valley of Visp in the Swiss Alps were studied that were collected along a transect with varying altitudes and host rock lithologies. The actual aim to attempt the reconstruction of Alpine paleoelevations was addressed by the analysis of sediments deposited under marine and terrestrial conditions during the Miocene and Oligocene, which were sampled from different locations in Switzerland, Germany and Austria. Further bentonite and fault gouge clay samples were used as reference material from low and high elevations. Results show that the isotopie composition of clay minerals can be influenced by several factors, such as the mode and site of their formation, possible isotope exchange (which is evident for 8D values), the samples' mineral composition (such as the presence of detrital material) and the deposition environment. With a consideration of these parameters and limitation to certain sample material, conclusions are drawn on the isotopie composition of the water from which the clay minerals formed. Most of the obtained values lie in the same range as has been reported in literature for foreland precipitation. The reconstruction of paleoelevation might be possible for selected sites with a geographical setting close to the Alpine chain or for intramontane basins. - La composition isotopique des argiles, qui se forment typiquement en contact avec des eaux superficielles, peut être utilisée pour obtenir des informations sur la paléoaltitude, la paléotopographie et le paléoclimat pendant leur création. La composition en isotopes stable (oxygène et hydrogène) des eaux de pluie est déterminée par l'altitude, la température, la distance depuis le lieu d'évaporation et par le taux de précipitation. Certains processus comme l'évaporation, l'interaction avec des minéraux et le mélange d'eaux d'origines variées peuvent aussi changer la composition des eaux de surface. Les argiles sont des pliyllosilicates hydratés qui sont crées par l'altération des roches au contact de ces eaux de surface et ils acquièrent une composition isotopique qui est soumise à un certain fractionnement. L'objectif de cette thèse est d'évaluer si l'effet de l'altitude des Alpes, est détectable dans la composition isotopique des sédiments du bassin d'avant-pavs pendant le Miocène. Après avoir établi la procédure analytique, des compositions isotopiques typiques de régions de hautes altitudes ont été determine sur les eaux de surfaces (rivières) et sur des échantillons de sols, le long d'une coupe dans la valée de Visp, dans les Alpes Suisses. Une reconstruction des paléoaltitudes Miocènes Alpines a ensuite été mené par l'analyse de sédiments marins et terrestres en utilisant des échantillons d'âges variés et provenant de Suisse, d'Allemagne et d'Autriche. Les résultats montrent que la composition isotopique des échantillons est impactée par de multiples facteurs, tels que le mode de et le lieu de formation. un possible échange isotopique tardif (surtout pour 5D). leur composition minéralogique et l'environnement de leur sédimentation. Après un examen prudent de ces paramètres, et en se limitant à un certain assortiment d'échatillons, on peut tirer des conclusions sur la composition isotopique des eaux originelles pour en déduire l'effet du climat et de la topographie.

Heterogeneity of atherosclerotic plaque phenotypes and composition in four different arterial beds: an intravascular ultrasound virtual histology study

Purpose: The purpose of this study was to compare the plaque morphology between coronary and peripheral arteries using intravascular ultrasound (IVUS). Methods: IVUS was performed in 68 patients with coronary and 93 with peripheral artery lesions (29 carotid, 50 renal, and 14 iliac). Plaques were classified as fibroatheroma (VH-FA) (further subclassified as thin-capped [VH-TCFA] and thick-capped [VH-ThCFA]), fibrocalcific plaque (VH-FC) and pathological intimal thickening (VH-PIT). Results: Plaque rupture (13% of coronary, 7% of carotid, 6% of renal, and 7% of iliac arteries; P=NS) and VH-TCFA (37% of coronary, 24% of carotid, 16% of renal, and 7% of iliac arteries; P=0.02) was observed in all arteries. Compared to coronary arteries, VH-FA was less frequently observed in renal (P<0.001) and iliac arteries (P<0.006), while VH-PIT and VH-FC were prevalent in both of these peripheral arteries. Lesions with positive remodeling demonstrated more characteristics of VH-FA in coronary, carotid, and renal arteries compared to those with intermediate/negative remodeling (all P<0.01). There was positive relationship between RI and percent necrotic core area in all four arteries. Conclusions: Atherosclerotic plaque phenotypes were heterogeneous among four different arteries. In contrast, the associations of remodeling mode with plaque phenotype and composition were similar among the various arterial beds.

Stable hydrogen and oxygen isotope composition of waters from mine tailings in different climatic environments

The stable isotope composition of waters (delta H-2, delta O-18) can be used as a natural tracer of hydrologic processes in systems affected by acid mine drainage. We investigated the delta H-2 and delta O-18 values of pore waters from four oxidizing sulfidic mine tailings impoundments in different climatic regions of Chile (Piuquenes at La Andina with Alpine climate, Cauquenes and Caren at El Teniente with Mediterranean climate, and Talabre at the Chuquicamata deposit with hyperarid climate). No clear relationship was found between altitude and isotopic composition. The observed displacement of the tailings pore waters from the local meteoric water line toward higher delta O-18 values (by similar to +2% delta O-18 relative to delta H-2) is partly due to water-rock interaction processes, including hydration and O-isotope exchange with sulfates and Fe(III) oxyhydroxides produced by pyrite oxidation. In most tailings, from the saturated zone toward the surface, isotopically different zones can be distinguished. Zone I is characterized by an upward depletion of H-2 and O-18 in the pore waters from the saturated zone and the lowermost vadose zone, due to ascending diffused isotopically light water triggered by the constant loss of water vapor by evaporation at the surface. In zone II, the capillary flow of a mix of vapor and liquid water causes an evaporative isotopic enrichment in H-2 and O-18. At the top of the tailings in dry climate a zone III between the capillary zone and the surface contains isotopically light diffused and atmospheric water vapor. In temperate climates, the upper part of the profile is affected by recent rainfall and zone III may not differ isotopically from zone II.

Serum Leptin Concentration, Body Mass Index and Incident Heart Failure: The Health, Aging, and Body Composition Study

Background: Leptin is produced primarily by adipocytes. Although originally associated with the central regulation of satiety and energy metabolism, increasing evidence indicates that leptin may be an important factor for congestive heart faire (CHF). In the study, we aimed to test the hypothesis that leptin may influence CHF pathophysiology via a pathway of increasing body mass index (BMI). Methods: We studied 2,389 elderly participants aged 70 and older (M; 1161, F: 1228) without CHF and with serum leptin measures at the Health Aging, and Body Composition study. We analyzed the association between serum leptin level and risk of incident CHF using Cox hazard proportional regression models. Elevated leptin level was defined as more than the highest quartile (Q4) of leptin distribution in the total sample for each gender. Adjusted-covariates included demographic, behavior, lipid and inflammation variables (partially-adjusted models), and further included BMI (fully-adjusted models). Results: In a mean 9-year follow-up, 316 participants (13.2%) developed CHF. The partially-adjusted models indicated that men and women with elevated serum leptin levels (>=9.89 ng/ml in men and >=25 ng/ml in women) had significantly higher risks of developing CHF than those with leptin level of less than Q4. The adjusted hazard ratios (95%CI) for incident CHF was 1.49 (1.04 -2.13) in men and 1.71 (1.12 -2.58) in women. However, these associations became non-significant after adjustment for including BMI for each gender. The fully-adjusted hazard ratios (95%CI) were 1.43 (0.94 -2.18) in men and 1.24 (0.77-1.99) in women. Conclusion: Subjects with elevated leptin levels have a higher risk of CHF. The study supports the hypothesis that the influence of leptin level on risk of CHF may be through a pathway related to increasing BMI.

Stable isotope composition of smectite in suevites at the Ries crater, Germany: Implications for hydrous alteration of impactites

The 24-km diameter Ries crater, Germany, exhibits well-preserved crater filling and surficial melt-rich breccia deposits that are believed to have been altered by post-impact hydrothermal fluids. The alteration mineralogy of the crater filling breccias is characterized by clay (smectite, chlorite) and a zeolite assemblage, and secondary clay phases (smectite, minor halloysite) in surficial melt-bearing breccia deposits. Using stable isotope analysis of secondary smectitic clay fractions, evidence of significant hydrous alteration of impactites at large water/rock ratios was found. The estimated fluid temperatures, using data derived by delta(18)O and delta D fractionation, suggest smectite precipitation in surficial breccias in equilibrium with meteoric fluids at temperatures 16 +/- 5 degrees C in agreement with the long-term variation of modern precipitation in the area. The stable isotope composition of smectite in crater-fill breccia, however, suggests a trend of monotonously increasing temperatures from 43 to 112 degrees C. with increasing depth through the breccia sequence. This demonstrates a different origin of alteration and temperature distribution for the surficial and crater filling melt-bearing impact breccias in the Ries crater. Our results suggest that the inverted structure of hydrothermal systems observed in some terrestrial impact craters, including the Ries crater, could indicate the initial configuration of a thermal anomaly in the crater filling sequence, but which is replaced with a normal hydrothermal convection in crater proper, during the course of post-impact cooling. (C) 2010 Elsevier B.V. All rights reserved.

Anatomy of contaminated aquifers of an industrial site: insights from the stable isotope compositions of waters and dissolved inorganic carbon

The hydrogen and oxygen isotopes of water and the carbon isotope composition of dissolved inorganic carbon (DIC) from different aquifers at an industrial site, highly contaminated by organic pollutants representing residues of the former gas production, have been used as natural tracers to characterize the hydrologic system. On the basis of their stable isotope compositions as well as the seasonal variations, different groups of waters (precipitation, surface waters, groundwaters and mineral waters) as well as seasonably variable processes of mixing between these waters can clearly be distinguished. In addition, reservoir effects and infiltration rates can be estimated. In the northern part of the site an influence of uprising mineral waters within the Quaternary aquifers, presumably along a fault zone, can be recognized. Marginal infiltration from the Neckar River in the cast and surface water infiltration adjacent to a steep hill on the western edge of the site with an infiltration rate of about one month can also be resolved through the seasonal variation. Quaternary aquifers closer to the centre of the site show no seasonal variations, except for one borehole close to a former mill channel and another borehole adjacent to a rain water channel. Distinct carbon isotope compositions and concentrations of DIC for these different groups of waters reflect variable influence of different components of the natural carbon cycle: dissolution of marine carbonates in the mineral waters, biogenic, soil-derived CO2 in ground- and surface waters, as well as additional influence of atmospheric CO2 for the surface waters. Many Quaternary aquifer waters have, however, distinctly lower delta(13)C(DIC) values and higher DIC concentrations compared to those expected for natural waters. Given the location of contaminated groundwaters at this site but also in the industrially well-developed valley outside of this site, the most likely source for the low C-13(DIC) values is a biodegradation of anthropogenic organic substances, in particular the tar oils at the site.

Impact du traitement par hormone de croissance sur la composition corporelle et le métabolisme osseux d'enfants nés avec un retard de croissance intra-utérin

Le retard de croissance intra-utérin (RCIU) est défini par une taille et un poids inférieurs au P10 pour l'âge gestationnel. Il est caractérisé, entre autre par une altération de la croissance foetale aboutissant à une résistance à l'hormone de croissance (HC). Bien que la majorité des sujets présente un certain rattrapage en taille, certains développent un retard de croissance ultérieur permanent. L'idée est donc née de traiter ces sujets par haute dose d'HC biosynthétique. La question des risques d'un tel traitement s'est posée en raison de l'effet diabétogène de l'HC et des modifications qu'elle peut induire sur la masse maigre, la masse grasse et la densité osseuse. Le but de l'étude a été d'évaluer l'impact sur la croissance et sur le volet métabolique. Dix enfants prépubères ayant présenté un RCIU sans croissance de rattrapage spontanée ont été traités par HC recombinante à des doses supra physiologiques (53-67 g/kg/jour). La taille, le poids, la taille assise ont été mesurés et des dosages d'IGF1, IGFBP3, glycémie et insuline ont été faits sur une base semestrielle alors qu'une densitométrie osseuse a été faite annuellement sur une période de 3 ans. Le gain en taille a été spectaculaire (+ 1.78 DS), correspondant à plus de 10 cm (p < 0.001). Sous traitement, l'insulinémie et le HOMA ont augmenté sans que ces augmentations soient significatives. La tolérance glucidique est restée dans la norme au prix d'une augmentation de la sécrétion d'insuline. La masse grasse a diminué alors que la masse maigre et la densité osseuse ont augmenté de façon significative. Ces résultats correspondent aux travaux d'autres groupes. Il reste à démontrer que l'hyperinsulinisme transitoire induit par l'HC n'ait pas d'effet néfaste à long terme et en particulier sur le risque de développer ou aggraver un syndrome métabolique à l'âge adulte.

Social insect genomes exhibit dramatic evolution in gene composition and regulation while preserving regulatory features linked to sociality.

Genomes of eusocial insects code for dramatic examples of phenotypic plasticity and social organization. We compared the genomes of seven ants, the honeybee, and various solitary insects to examine whether eusocial lineages share distinct features of genomic organization. Each ant lineage contains ∼4000 novel genes, but only 64 of these genes are conserved among all seven ants. Many gene families have been expanded in ants, notably those involved in chemical communication (e.g., desaturases and odorant receptors). Alignment of the ant genomes revealed reduced purifying selection compared with Drosophila without significantly reduced synteny. Correspondingly, ant genomes exhibit dramatic divergence of noncoding regulatory elements; however, extant conserved regions are enriched for novel noncoding RNAs and transcription factor-binding sites. Comparison of orthologous gene promoters between eusocial and solitary species revealed significant regulatory evolution in both cis (e.g., Creb) and trans (e.g., fork head) for nearly 2000 genes, many of which exhibit phenotypic plasticity. Our results emphasize that genomic changes can occur remarkably fast in ants, because two recently diverged leaf-cutter ant species exhibit faster accumulation of species-specific genes and greater divergence in regulatory elements compared with other ants or Drosophila. Thus, while the "socio-genomes" of ants and the honeybee are broadly characterized by a pervasive pattern of divergence in gene composition and regulation, they preserve lineage-specific regulatory features linked to eusociality. We propose that changes in gene regulation played a key role in the origins of insect eusociality, whereas changes in gene composition were more relevant for lineage-specific eusocial adaptations.

Lipid composition of fingermark residue and donor classification using GC/MS

Lipids available in fingermark residue represent important targets for enhancement and dating techniques. While it is well known that lipid composition varies among fingermarks of the same donor (intra-variability) and between fingermarks of different donors (inter-variability), the extent of this variability remains uncharacterised. Thus, this worked aimed at studying qualitatively and quantitatively the initial lipid composition of fingermark residue of 25 different donors. Among the 104 detected lipids, 43 were reported for the first time in the literature. Furthermore, palmitic acid, squalene, cholesterol, myristyl myristate and myristyl myristoleate were quantified and their correlation within fingermark residue was highlighted. Ten compounds were then selected and further studied as potential targets for dating or enhancement techniques. It was shown that their relative standard deviation was significantly lower for the intra-variability than for the inter-variability. Moreover, the use of data pretreatments could significantly reduce this variability. Based on these observations, an objective donor classification model was proposed. Hierarchical cluster analysis was conducted on the pre-treated data and the fingermarks of the 25 donors were classified into two main groups, corresponding to "poor" and "rich" lipid donors. The robustness of this classification was tested using fingermark replicates of selected donors. 86% of these replicates were correctly classified, showing the potential of such a donor classification model for research purposes in order to select representative donors based on compounds of interest.

Determination of chemical composition and its relationship with optical properties of Ti-N and Ti-V-N sputtered thin films

In the investigation of thin films of transition metal nitrides, an essential role is played by the accurate determination of their chemical composition. Actually the chemical composition depends on the deposition parameters and influences the optical properties. These relations are illustrated in thin films of TiNx and (Ti1-yVy)N-x deposited by reactive magnetron sputtering from composite targets of the elements. By variation of the nitrogen partial pressure and the target composition, different samples have been obtained. The chemical composition has been measured by electron probe microanalysis at low irradiation voltages. The optical properties are evaluated by ex-situ ellipsometry. Using the screened Drude model, they are correlated with the differences in composition. Adding vanadium or nitrogen in Ti-N is shown to have the same effect on the optical properties.