Aluminum toxicity in a tropical montane forest ecosystem in southern Ecuador

Aluminum phytotoxicity frequently occurs in acid soils (pH < 5.5) and was therefore discussed to affect ecosystem functioning of tropical montane forests. The susceptibility to Al toxicity depends on the sensitivity of the plant species and the Al speciation in soil solution, which can vary highly depending e.g., on pH, ionic strength, and dissolved organic matter. An acidification of the ecosystem and periodic base metal deposition from Saharan dust may control plant available Al concentrations in the soil solutions of tropical montane rainforests in south Ecuador. The overall objective of my study was to assess a potential Al phytotoxicity in the tropical montane forests in south Ecuador. For this purpose, I exposed three native Al non-accumulating tree species (Cedrela odorata L., Heliocarpus americanus L., and Tabebuia chrysantha (Jacq.) G. Nicholson) to increased Al concentrations (0 – 2400 μM Al) in a hydroponic experiment, I established dose-response curves to estimate the sensitivity of the tree species to increased Al concentrations, and I investigated the mechanisms behind the observed effects induced by elevated Al concentrations. Furthermore, the response of Al concentrations and the speciation in soil solution to Ca amendment in the study area were determined. In a final step, I assessed all major Al fluxes, drivers of Al concentrations in ecosystem solutions, and indicators of Al toxicity in the tropical montane rainforest in Ecuador in order to test for indications of Al toxicity. In the hydroponic experiment, a 10 % reduction in aboveground biomass production occurred at 126 to 376 μM Al (EC10 values), probably attributable to decreased Mg concentrations in leaves and reduced potosynthesis. At 300 μM Al, increased root biomass production of T. chrysantha was observed. Phosphorus concentrations in roots of C. odorata and T. chrysantha were significantly highest in the treatment with 300 μM Al and correlated significantly with root biomass, being a likely reason for stimulated root biomass production. The degree of organic complexation of Al in the organic layer leachate, which is central to plant nutrition because of the high root density, and soil solution from the study area was very high (mean > 99 %). The resulting low free Al concentrations are not likely to affect plant growth, although the concentrations of potentially toxic Al3+ increased with soil depth due to higher total Al and lower dissolved organic matter concentrations in soil solutions. The Ca additions caused an increase of Al in the organic layer leachate, probably because Al3+ was exchanged against the added Ca2+ ions while pH remained constant. The free ion molar ratios of Ca2+:Al3+ (mean ratio ca. 400) were far above the threshold (≤ 1) for Al toxicity, because of a much higher degree of organo-complexation of Al than Ca. High Al fluxes in litterfall (8.8 – 14.2 kg ha−1 yr−1) indicate a high Al circulation through the ecosystem. The Al concentrations in the organic layer leachate were driven by the acidification of the ecosystem and increased significantly between 1999 and 2008. However, the Ca:Al molar ratios in organic layer leachate and all aboveground ecosystem solutions were above the threshold for Al toxicity. Except for two Al accumulating and one non-accumulating tree species, the Ca:Al molar ratios in tree leaves from the study area were above the Al toxicity threshold of 12.5. I conclude that toxic effects in the hydroponic experiment occurred at Al concentrations far above those in native organic layer leachate, shoot biomass production was likely inhibited by reduced Mg uptake, impairing photosynthesis, and the stimulation of root growth at low Al concentrations can be possibly attributed to improved P uptake. Dissolved organic matter in soil solutions detoxifies Al in acidic tropical forest soils and a wide distribution of Al accumulating tree species and high Al fluxes in the ecosystem do not necessarily imply a general Al phytotoxicity.

What happens to the bone flap? Long-term outcome after reimplantation of cryoconserved bone flaps in a consecutive series of 92 patients.

BACKGROUND Reimplantation of cryoconserved autologous bone flaps is a standard procedure after decompressive craniotomies. Aseptic necrosis and resorption are the most frequent complications of this procedure. At present there is no consensus regarding the definition of the relevant extent and indication for surgical revision. The objective of this retrospective analysis was to identify the incidence of bone flap resorption and the optimal duration of follow-up. METHODS Between February 2009 and March 2012, 100 cryoconserved autologous bone flaps were reimplanted at the Department of Neurosurgery, Inselspital Bern. Three patients were not available for follow-up, and five patients died before follow-up. All patients underwent follow-up at 6 weeks and a second follow-up more than 12 months postoperatively. A clinical and CT-based score was developed for judgment of relevance and decision making for surgical revision. RESULTS Mean follow-up period was 21.6 months postoperatively (range: 12 to 47 months); 48.9 % (45/92) of patients showed no signs of bone flap resorption, 20.7 % (19/92) showed minor resorption with no need for surgical revision, and 30.4 % (28/92) showed major resorption (in 4 % of these the bone flap was unstable or collapsed). CONCLUSIONS Aseptic necrosis and resorption of reimplanted autologous bone flaps occurred more frequently in our series of patients than in most reports in the literature. Most cases were identified between 6 and 12 months postoperatively. Clinical observation or CT scans of patients with autologous bone flaps are recommended for at least 12 months. Patient-specific implants may be preferable to autologous bone flaps.

Grazing behaviour, physical activity and metabolic profile of two Holstein strains in an organic grazing system

The challenge for sustainable organic dairy farming is identification of cows that are well adapted to forage-based production systems. Therefore, the aim of this study was to compare the grazing behaviour, physical activity and metabolic profile of two different Holstein strains kept in an organic grazing system without concentrate supplementation. Twelve Swiss (HCH ; 566 kg body weight (BW) and 12 New Zealand Holstein-Friesian (HNZ ; 530 kg BW) cows in mid-lactation were kept in a rotational grazing system. After an adaptation period, the milk yield, nutrient intake, physical activity and grazing behaviour were recorded for each cow for 7 days. On three consecutive days, blood was sampled at 07:00, 12:00 and 17:00 h from each cow by jugular vein puncture. Data were analysed using linear mixed models. No differences were found in milk yield, but milk fat (3.69 vs. 4.05%, P = 0.05) and milk protein percentage (2.92 vs. 3.20%, P < 0.01) were lower in HCH than in HNZ cows. Herbage intake did not differ between strains, but organic matter digestibility was greater (P = 0.01) in HCH compared to HNZ cows. The HCH cows spent less (P = 0.04) time ruminating (439 vs. 469 min/day) and had a lower (P = 0.02) number of ruminating boli when compared to the HNZ cows. The time spent eating and physical activity did not differ between strains. Concentrations of IGF-1 and T3 were lower (P ≤ 0.05) in HCH than HNZ cows. In conclusion, HCH cows were not able to increase dry matter intake in order to express their full genetic potential for milk production when kept in an organic grazing system without concentrate supplementation. On the other hand, HNZ cows seem to compensate for the reduced nutrient availability better than HCH cows but could not use that advantage for increased production efficiency

Malnutrition in the era of DRG

Malnutrition in hospital patients is of important medical and economic significance. The adverse consequences of malnutrition on quality of life and many more factors such as morbidity, mortality, tolerance of treatments and length of hospital stay are well documented in the medical literature. Nevertheless, the effects of malnutrition are still often underestimated and hence malnutrition is not recognised as a distinct diagnosis. Moreover, malnutrition is rarely documented in medical reports and often not adequately treated with adverse effects. The reason for this neglectfulness are diverse, e. g. inadequate training of doctors and nurses in clinical nutrition and lack of sensibilisation of the hospital staff for the problem of malnutrition. Therefore, a systematic screening for malnutrition is rarely undertaken in Swiss hospitals. The introduction of the Swiss-DRG system (DRG, diagnosis related groups) in January 2012 gave the chance to boost recording and to document malnutrition in a standardised way in the patient history, and to code precisely malnutrition as a distinct diagnosis. Moreover, this approach allowed to document the specific nutritional therapy. Here, we describe the way of documenting and coding malnutrition in the Swiss-DRG system and the medical and economic consequences of this procedure.

Do executive dysfunction and freezing of gait in Parkinson's disease share the same neuroanatomical correlates?

Current hypotheses postulate a relationship between executive dysfunction and freezing of gait (FOG) in Parkinson's disease (PD). Hitherto, most evidence comes from entirely clinical approaches, while knowledge about this relationship on the morphological level is sparse. The aim of this study was therefore to assess the overlap of gray matter atrophy associated with FOG and executive dysfunction in PD. We included 18 PD patients with FOG and 20 without FOG in our analysis. A voxel-based morphometry approach was used to reveal voxel clusters in the gray matter which were associated with FOG and executive dysfunction as measured by the Frontal Assessment Battery, respectively. Conjunction analysis was applied to detect overlaps of the associated patterns. FOG correlated with different cortical clusters in the frontal and parietal lobes, whereas those associated with the FAB scores were, although widespread, widely confined to the frontal lobe. Conjunction analysis revealed a significant cluster of gray matter loss in the right dorsolateral prefrontal cortex. We could show that the patterns of neurodegeneration associated with FOG and executive dysfunction (as measured by the FAB) share atrophic changes in the same cortical areas. However, there is also a considerable number of cortical areas where neurodegenerative changes are only unique for either sign. Particularly, the involvement of parietal lobe areas seems to be more specific for FOG.

Quantifying differences in land use emission estimates implied by definition discrepancies

The quantification of CO2 emissions from anthropogenic land use and land use change (eLUC) is essential to understand the drivers of the atmospheric CO2 increase and to inform climate change mitigation policy. Reported values in synthesis reports are commonly derived from different approaches (observation-driven bookkeeping and process-modelling) but recent work has emphasized that inconsistencies between methods may imply substantial differences in eLUC estimates. However, a consistent quantification is lacking and no concise modelling protocol for the separation of primary and secondary components of eLUC has been established. Here, we review differences of eLUC quantification methods and apply an Earth System Model (ESM) of Intermediate Complexity to quantify them. We find that the magnitude of effects due to merely conceptual differences between ESM and offline vegetation model-based quantifications is ~ 20 % for today. Under a future business-as-usual scenario, differences tend to increase further due to slowing land conversion rates and an increasing impact of altered environmental conditions on land-atmosphere fluxes. We establish how coupled Earth System Models may be applied to separate secondary component fluxes of eLUC arising from the replacement of potential C sinks/sources and the land use feedback and show that secondary fluxes derived from offline vegetation models are conceptually and quantitatively not identical to either, nor their sum. Therefore, we argue that synthesis studies should resort to the "least common denominator" of different methods, following the bookkeeping approach where only primary land use emissions are quantified under the assumption of constant environmental boundary conditions.

Evaluation of leaders – does gender still matter?

Purpose: Leadership positions are still stereotyped as male, especially in male-dominated fields such as STEM. Therefore, women in such positions run the risk of being evaluated less favorably than men. Our study investigates how female and male leaders in existing teams (engineering project) are evaluated, and how these evaluations change over time. Design/Methodology: Participants worked in 45 teams to develop specific engineering projects. Evaluations of 45 leaders (33% women) by 258 team members (39% women) were analyzed, that is, leaders’ self-evaluation and their evaluation by team members. Results: Although female and male leaders did not differ in their self-evaluations at the beginning of the project, female leaders evaluated themselves better within time. However, team members evaluated female leaders better than male leaders at the beginning of the project. These gender differences disappeared over the time. Limitations: It should be replicated in a non-student sample. Implications: The results show that female leaders entering a male-dominated field (engineering) are evaluated better by team members than male leaders at the beginning of the team work, in line with the ‘shifting standard model’ (Biernat & Fuegen, 2001). While the initial impression formation of female and male leaders is influenced by category membership, its impact decreases over time as a consequence of individualization (Fiske & Neuberg, 1990); this results in similar evaluations over time. Originality: To our knowledge this is the first study to systematically test perceptions of change in the evaluation over time of female and male leaders in natural setting.

Influence of quantized massive matter fields on the Casimir effect

Charged massive matter fields of spin-0 and spin- 1/2 are quantized in the presence of an external uniform magnetic field in a spatial region bounded by two parallel plates. The most general set of boundary conditions at the plates, that is required by mathematical consistency and the self-adjointness of the Hamiltonian operator, is employed. The vacuum fluctuations of the matter field in the case of the magnetic field orthogonal to the plates are analyzed, and it is shown that the pressure from the vacuum onto the plates is positive and independent of the boundary condition, as well as of the distance between the plates. Possibilities of the detection of this new-type Casimir effect are discussed. Read More: http://www.worldscientific.com/doi/10.1142/S0217732315500996

Evaluation of Leaders – Does Gender Really Matter?

We examined the leaders’ self-evaluation and their evaluation by subordinates. We found that, over time, female leaders evaluated themselves better than male leaders and that subordinates evaluated female leaders better than male leaders at the beginning of the project. The latter gender differences disappeared over the course of the project.

Erythropoietin for the Repair of Cerebral Injury in Very Preterm Infants (EpoRepair).

BACKGROUND Preterm infants suffering from intraventricular hemorrhage (IVH) are at increased risk for neurodevelopmental impairment. Observational data suggest that recombinant human erythropoietin (rEPO) improves long-term cognitive outcome in infants with IVH. Recent studies revealed a beneficial effect of early high-dose rEPO on white matter development in preterm infants determined by magnetic resonance imaging (MRI). OBJECTIVES To summarize the current evidence and to delineate the study protocol of the EpoRepair trial (Erythropoietin for the Repair of Cerebral Injury in Very Preterm Infants). METHODS The study involves a review of the literature and the design of a double-blind, placebo-controlled, multicenter trial of repetitive high-dose rEPO administration, enrolling 120 very preterm infants with moderate-to-severe IVH diagnosed by cranial ultrasound in the first days of life, qualitative and quantitative MRI at term-equivalent age and long-term neurodevelopmental follow-up until 5 years of age. RESULTS AND CONCLUSIONS The hypothesis generated by observational data that rEPO may improve long-term cognitive outcomes of preterm infants suffering from IVH are to be confirmed or refuted by the randomized controlled trial, EpoRepair.

Long-distance transport of alkali metals in maturing wheat

The alkali metals cesium, rubidium, lithium and sodium were introduced together with strontium via flaps into leaf laminas or into the stem of maturing, intact winter wheat (Triticum aestivum L. cv. Arina) grown in a field. Long-distance transport of these elements and the influence of the application date and of different application positions were investigated. The phloem-immobile Sr served as a marker for the distribution of the xylem sap in the plants. Dry matter accumulation in the grains and the transpiration per shoot were not markedly affected by the treatments as compared to control plants. The phloem mobility was rather high for Cs and Rb. Li was almost immobile in the phloem (similarly to Sr). An application into the cut stem xylem below the second leaf node contributed more to the contents in the grains than an application into the flag leaf. An earlier feeding date led to a higher accumulation in the grains. The marked losses of the elements applied during maturation (most pronounced for Li) can be explained by leakage in the rain.

Long-distance transport of cobalt and nickel in maturing wheat

Cobalt, nickel and strontium were introduced via flaps into leaf laminas or into the stem of maturing, intact winter wheat (Triticum aestivum L., cv. `Arina') grown under natural conditions in a field. Long-distance transport of these elements and the influence of the application date and of different application positions were investigated. The dry-matter accumulation in the grains was not markedly affected by the treatments as compared to untreated control plants. The phloem-immobile strontium served as a marker for the distribution of the xylem sap in the plants. After foliar application, nickel accumulated more rapidly and in higher quantities in the grains than cobalt. Therefore, nickel has a slightly better phloem mobility than cobalt. Regardless of the application date, a higher percentage of the two elements was transported from the flag leaf lamina than from the second or third lamina from the top to the grains. These results indicate that the leaf position is highly relevant for the transfer of the heavy metals investigated to the ear. Introduction into the stem led to a higher accumulation of nickel and cobalt in the grains than introduction into one of the leaves. An earlier feeding date caused a higher accumulation of nickel and cobalt in the grains when introduced into the stem. In contrast, no major differences between earlier and later feeding dates were detected when the elements were introduced into the leaves. Losses of the applied elements were detected during maturation and can be explained by leakage in the rain.

RELATIONS AMONG REMEMBERED PARENTAL ACCEPTANCE AND BEHAVIORAL CONTROL IN CHILDHOOD, ADULTS' CURRENT PSYCHOLOGICAL ADJUSTMENT, AND CAREER INDECISIVENESS

This study tested the hypothesis that career indecisiveness among men tends to be associated with different levels of self-reported psychological adjustment and with different remembrances of parental (maternal and paternal) acceptance and behavioral control in childhood from those of women. One hundred twenty-six respondents ages 17 through 54 (M = 23.7 years, SD = 8.21 years) participated in this study. Thirty-seven where males; 90 were females. Measures used in this study included the Career Decision Scale, the Adult version of the Parental Acceptance-Rejection/Control Questionnaire for mothers and for fathers, and the Adult version of the Personality Assessment Questionnaire. Both men and women remembered their mothers as well as their fathers as being loving in childhood. Additionally, men and women remembered both parents as being moderately behaviorally controlling in childhood. Finally, both men and women reported a fair level of psychological maladjustment. And on average, both men and women were fairly indecisive about their careers. Results of analyses supported the hypothesis in that career indecisiveness among women but not men was significantly correlated with remembered maternal and paternal acceptance in childhood, as well as with self-reported psychological adjustment and age. However, only women’s self-reported psychological adjustment made a significant and unique contribution to variations in their reports of career indecisiveness. None of the predictor variables were significantly associated with career indecisiveness among men.

Soil characteristics and decomposition of organic matter on Anchorage, Signy and Falkland Islands

Antarctic terrestrial ecosystems have poorly developed soils and currently experience one of the greatest rates of climate warming on the globe. We investigated the responsiveness of organic matter decomposition in Maritime Antarctic terrestrial ecosystems to climate change, using two study sites in the Antarctic Peninsula region (Anchorage Island, 67°S; Signy Island, 61°S), and contrasted the responses found with those at the cool temperate Falkland Islands (52°S). Our approach consisted of two complementary methods: (1) Laboratory measurements of decomposition at different temperatures (2, 6 and 10 °C) of plant material and soil organic matter from all three locations. (2) Field measurements at all three locations on the decomposition of soil organic matter, plant material and cellulose, both under natural conditions and under experimental warming (about 0.8 °C) achieved using open top chambers. Higher temperatures led to higher organic matter breakdown in the laboratory studies, indicating that decomposition in Maritime Antarctic terrestrial ecosystems is likely to increase with increasing soil temperatures. However, both laboratory and field studies showed that decomposition was more strongly influenced by local substratum characteristics (especially soil N availability) and plant functional type composition than by large-scale temperature differences. The very small responsiveness of organic matter decomposition in the field (experimental temperature increase <1 °C) compared with the laboratory (experimental increases of 4 or 8 °C) shows that substantial warming is required before significant effects can be detected.