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Proglacial environments are ideal for studying the development of soils through the changes of rocks exposed by glacier retreat to weathering and microbial processes. Carbon (C) and nitrogen (N) contents as well as soil pH and soil elemental compositions are thought to be dominant factors structuring the bacterial, archaeal and fungal communities in the early stages of soil ecosystem formation. However, the functional linkages between C and N contents, soil composition and microbial community structures remain poorly understood. Here, we describe a multivariate analysis of geochemical properties and associated microbial community structures between a moraine and a glaciofluvial outwash in the proglacial area of a High Arctic glacier (Longyearbreen, Svalbard). Our results reveal distinct differences in developmental stages and heterogeneity between the moraine and the glaciofluvial outwash. We observed significant relationships between C and N contents, δ13Corg and δ15N isotopic ratios, weathering and microbial abundance and community structures. We suggest that the observed differences in microbial and geochemical parameters between the moraine and the glaciofluvial outwash are primarily a result of geomorphological variations of the proglacial terrain.
Glaciers retreating in response to climate warming are progressively exposing primary mineral substrates to surface conditions. As primary production is constrained by nitrogen (N) availability in these emerging ecosystems, improving our understanding of how N accumulates with soil formation is of critical concern. In this study, we quantified how the distribution and speciation of N, as well as rates of free-living biological N fixation (BNF), change along a 2000-year chronosequence of soil development in a High Arctic glacier forefield. Our results show the soil N pool increases with time since exposure and that the rate at which it accumulates is influenced by soil texture. Further, all N increases were organically bound in soils which had been ice-free for 0–50 years. This is indicative of N limitation and should promote BNF. Using the acetylene reduction assay technique, we demonstrated that microbially mediated inputs of N only occurred in soils which had been ice-free for 0 and 3 years, and that potential rates of BNF declined with increased N availability. Thus, BNF only supports N accumulation in young soils. When considering that glacier forefields are projected to become more expansive, this study has implications for understanding how ice-free ecosystems will become productive over time.
Despite substantial advances in treatment and management strategies for major depression, less than 50% of patients respond to first-line antidepressant treatment or psychotherapy. Given the growing number of controlled studies of psychotherapy for treatment-resistant depression (TRD) and the preference for psychotherapy of depressed subjects as a treatment option, we conducted a meta-analysis and meta-regression analysis to investigate the effectiveness of psychotherapy for TRD. Seven different psychotherapies were studied in 21 trials that included a total of 25 comparisons. In three comparisons of psychotherapy v. treatment as usual (TAU) we found no evidence to conclude that there is a significant benefit of psychotherapy as compared with TAU. In 22 comparisons of add-on psychotherapy plus TAU v. TAU only, we found a moderate general effect size of 0.42 (95% CI 0.29–0.54) in favor of psychotherapy plus TAU. The meta-regression provided evidence for a positive association between baseline severity as well as group v. individual therapy format with the treatment effect. There was no evidence for publication bias. Most frequent investigated treatments were cognitive behavior therapy, interpersonal psychotherapy, mindfulness-based cognitive therapy, and cognitive behavioral analysis system of psychotherapy. Our meta-analysis provides evidence that, in addition to pharmacological and neurostimulatory treatments, the inclusion of add-on of psychotherapy to TAU in guidelines for the treatment of TRD is justified and will provide better outcomes for this difficult-to-treat population.
Results are reported here of an investigation into the effects of three carboxylic acid additives (tartaric, maleic and citric acids) on the precipitation of calcium sulfate phases. Precipitation reactions were followed at pH 7 in the pure CaSO4 system and in experiments with 0–20 ppm carboxylic acids added using in situ UV-VIS spectrophotometry (turbidity). The solid products were characterized in terms of their mineralogical composition, using X-ray diffraction, during and at the end of each reaction, and in terms of their morphological features, by scanning electron microscopy. All additives increased the time needed for turbidity to develop (induction time, start of precipitation) and the comparison between additive and additive-free experiments showed that, at equivalent concentrations, citric acid performed far better than the other two carboxylic acids. In all cases bassanite precipitated first and with time it transformed to gypsum. The addition of citrate stabilized bassanite and changed the final gypsum habit from typical needle-like crystals in the pure CaSO4 system to plates in the citrate-additive experiments.
The crystallization of hexagonal NdCO3OH through hydrothermal synthesis carried out at slow (reaching the desired temperature within 100 min) and quick (50 min) rates of heating but at variable temperatures (165–220ºC) are reported here. The formation of NdCO3OH occurs via the crystallization of an amorphous precursor. Both the precursor and the crystalline NdCO3OH were characterized by X-ray diffraction, infrared spectroscopy and high-resolution electron microscopy. The mechanism of crystallization is very dependent on the experimental conditions (rate of heating and temperature treatment). With increasing temperature, the habit of NdCO3OH crystals changes progressively to more complex spherulitic or dendritic morphologies. The development of these crystal morphologies is suggested here to be controlled by the level at which supersaturation was reached in the aqueous solution during the breakdown of the amorphous precursor. At the highest temperature (220ºC) and during rapid heating (50 min) the amorphous precursor breaks down rapidly and the fast supersaturation promotes spherulitic growth. At the lowest temperature (165ºC) and slow heating (100 min), however, the supersaturation levels are approached more slowly than required for spherulitic growth, and thus more regular, previously unseen, triangular pyramidal shapes form.
The formation of crystalline rare earth element (REE) (e.g. La, Ce, Pr, Nd) carbonates from aqueous solutions was examined at ambient temperature using UV-Vis spectrophotometry, combined with X-ray diffraction, high-resolution microscopy and infrared spectroscopy. In all experiments REE-lanthanites (REE2(CO3)3·8H2O) formed via a highly hydrated, nanoparticulate and poorlyordered REE-carbonate precursor. The lifetime of this precursor as well as the kinetics of crystallization of the various REE-lanthanites were dependent on the specific REE3+ ion involved in the reaction. The induction time and the time needed to fully form the crystalline REE-lanthanite end products increase linearly with the ionic potential. The authors show here that the differences in ion size and ionic potential as well as differences in dehydration energy of the REE3+ ions control the lifetime of the poorly ordered precursor and thus also the crystallization kinetics of the REE-lanthanites; furthermore, they also affect the structural characteristics (e.g. unit-cell dimensions and idiomorphism) of the final crystalline lanthanites.
Disorders of the ovary can lead to a wide range of endocrinologic and malignant conditions, many of which are linked with fertility. This comprehensive, yet succinct book presents a multidisciplinary approach to address the major issues in diagnosing and managing ovarian disorders. Beginning with the complex functioning of the normal ovary, the editors address many of the major issues in women's health. New chapters on ovarian cysts, menopause, the aging ovary, early detection and risk assessment of ovarian cancer, screening, stage I ovarian cancer and many other topics have been added to this third edition. Assisted reproductive techniques, diagnostic imaging modalities, minimally invasive surgery, and chemotherapy have advanced dramatically and the chapters have been updated accordingly. This well-documented volume has been fully updated with contemporary references and chapters written by current leaders in their field. A must-read for gynecologists, oncologists, obstetricians, pathologists and researchers in human reproductive sciences.
Reef-building corals are fundamental to the most diverse marine ecosystems, and the coral–dinoflagellate (zooxanthellae) associations on fine scale remains largely unknown. Spatial variation in the diversity of symbiotic dinoflagellates of two scleractinian coral species was studied in an upwelling region near Qinlan Harbor in eastern Hainan Island, China. Results showed that stress-tolerant Symbiodinium trenchi in individual colonies of Galaxea fascicularis occurred more frequently in shallow back-reef than in deep fore-reef. The higher symbiont diversity was found in colonies of G. fascicularis in shallow and close to the harbour mouth whereas the coral Pocillipora damicornis always harboured Symbiodinium internal transcribed spacer 2 (ITS2) types C1c or C42a. Furthermore, both corals were found to simultaneously contain Symbiodinium ITS2 types belonging to two distinct phylogenetic clades (C and D). This indicates that the distribution of genetically distinct Symbiodinium may correlate with light regime and possibly temperature in some (but not all) colonies at particular locations, which we interpret as holobiont acclimation to the local environmental conditions. Therefore, we conclude that reef-building corals can adapt to the local environment by harbouring genetically distinct symbionts but depend on their respective symbiont transmission modes.
Effective management of Chinese citrus fly, Bactrocera minax (Enderlein) (Diptera: Tephritidae), is hindered by a lack of knowledge about its movements. We determined the feasibility of using harmonic radar technology to measure natural dispersal of B. minax. Tests demonstrated that 3.8 mg tags representing 8% of average insect weight had no visible impact on the ability of flies to takeoff and maintain flight. More than 86% of flies retained their tags for at least 5 days, and there was no significant mortality. Neither adhesive tested for tag mounting affected the survival of flies. Presence of the vertical dorsal tag did not prevent or hamper vertical movement. Together, results validate the use of tags weighing up to 3.8 mg for radar or telemetric study of dispersal ecology of B. minax.
Zirconate pyrochlores, A2Zr2O7, are important potential nuclear waste forms for Puimmobilization. The binary Gd2(Ti2-xZrx)O7 has been shown to have increasing resistance to ionirradiation damage with the increasing Zr content, and Gd2Zr2O7 is radiation resistant to a 1 MeV Kr+ ion irradiation at 25 K to a dose of 5 dpa. In this study, a 1.5 MeV Xe+ irradiation was completed for zirconate pyrochlores A2Zr2O7 (A=La, Nd, Sm, Gd). The radiation resistance decreases with an increase of the ionic radius of A-site cation. La2Zr2O7 is the first zirconate pyrochlore to be amorphized by ion beam irradiation, and the critical amorphization temperature, Tc, is ∼310 K. The susceptibility of La2Zr2O7 to ion beam damage is related to its structure, which shows the largest deviation from the ideal fluorite structure. These results are also consistent with calculations of the cation antisite formation energy in the pyrochlore structure. The ion irradiation-induced pyrochlore-to-fluorite transformation occurred in all of the irradiated zirconate pyrochlore phases. Based on the results for Gd2Ti2-xZrxO7 and A2Zr2O7, the defect fluorite structures are stable when the ionic radii ratio rA/rB≤1.54; beyond this limit, the defect fluorite structure becomes increasingly unstable relative to the amorphous state.