442 research outputs found

    Ecosystem carbon dynamics in logged forest of Malaysian Borneo

    Full text link
    The tropical rainforest of Borneo is heavily disturbed by logging, to date less than half of the original forest cover remains. To counteract such development logged forest is rehabilitated to regenerate its natural protective function. In this thesis we consider the carbon budget of logged forest and the ecology of the trees that are planted for rehabilitation. We show that the logged forest under study differs from unlogged forest due to the lack of the dominant trees and hence the organic carbon that is stored in their biomass. Besides this difference our results indicate that logged forest can maintain its protective function for carbon storage and is therefore worth preserving. The dominant trees, known as dipterocarps, belong to the Dipterocarpaceae family and are keystone species of the lowland forests of Borneo. On the basis of experimental work we study the carbon dynamics of selected dipterocarp species at the seedling stage. With plant physiological measurements of the carbohydrate stores we demonstrate how seedlings adapt to a changing light environment. Our results show that photosynthates are invested into growth or carbohydrate reserves, irrespective of the tree species under study. Further, experimental evidence suggests that the ectomycorrhizal association (plant-fungi-symbiosis) is crucial for the growth of seedlings and should therefore be considered for forest rehabilitation measures. In contrast we could not find evidence for a complex ectomycorrhiza-network between dipterocarp trees and seedlings in logged forest

    Effects of seed predators of different body size on seed mortality in Bornean logged gorest

    Get PDF
    Background The Janzen-Connell hypothesis proposes that seed and seedling enemies play a major role in maintaining high levels of tree diversity in tropical forests. However, human disturbance may alter guilds of seed predators including their body size distribution. These changes have the potential to affect seedling survival in logged forest and may alter forest composition and diversity. Methodology/Principal Findings We manipulated seed density in plots beneath con- and heterospecific adult trees within a logged forest and excluded vertebrate predators of different body sizes using cages. We show that small and large-bodied predators differed in their effect on con- and heterospecific seedling mortality. In combination small and large-bodied predators dramatically decreased both con- and heterospecific seedling survival. In contrast, when larger-bodied predators were excluded small-bodied predators reduced conspecific seed survival leaving seeds coming from the distant tree of a different species. Conclusions/Significance Our results suggest that seed survival is affected differently by vertebrate predators according to their body size. Therefore, changes in the body size structure of the seed predator community in logged forests may change patterns of seed mortality and potentially affect recruitment and community composition

    Eccentric endurance training in subjects with coronary artery disease: a novel exercise paradigm in cardiac rehabilitation?

    Get PDF
    This study evaluated the effects of 8weeks of eccentric endurance training (EET) in male subjects (age range 42-66years) with coronary artery disease (CAD). EET was compared to concentric endurance training (CET) carried out at the same metabolic exercise intensity, three times per week for half an hour. CET (n=6) was done on a conventional cycle ergometer and EET (n=6) on a custom-built motor-driven ergometer. During the first 5weeks of the training program the metabolic load was progressively increased to 60% of peak oxygen uptake in both groups. At this metabolic load, mechanical work rate achieved was 97 (8)W [mean (SE)] for CET and 338 (34)W for EET, respectively. Leg muscle mass was determined by dual-energy X-ray absorptiometry, quadriceps strength with an isokinetic dynamometer and muscle fibre composition of the vastus lateralis muscle with morphometry. The leg muscle mass increased significantly in both groups by some 3%. Strength parameters of knee extensors improved in EET only. Significant changes of +11 (4.9)%, +15 (3.2)% and +9 (2.5)% were reached for peak isometric torque and peak concentric torques at 60°s−1 and 120°s−1, respectively. Fibre size increased significantly by 19% in CET only. In conclusion, the present investigation showed that EET is feasible in middle-aged CAD patients and has functional advantages over CET by increasing muscle strength. Muscle mass increased similarly in both groups whereas muscle structural composition was differently affected by the respective training protocols. Potential limitations of this study are the cautiously chosen conditioning protocol and the restricted number of subject

    Glutathione-S-transferase subtypes α and π as a tool to predict and monitor graft failure or regeneration in a pilot study of living donor liver transplantation

    Get PDF
    <p>Abstract</p> <p>Objective</p> <p>Glutathione-S-Transferase (GST) subtype α and π are differentially expressed in adult liver tissue. Objective of the study was if GST α and p may serve as predictive markers for liver surgery, especially transplantations.</p> <p>Methods</p> <p>13 patients receiving living donor liver transplantation (LDLT) and their corresponding donors were analyzed for standard serum parameters (ALT, AST, gGT, bilirubin) as well as GST-α and -π before LDLT and daily for 10 days after LDLT. Patients (R) and donors (D) were grouped according to graft loss (R1/D1) or positive outcome (R2/D2) and above named serum parameters were compared between the groups.</p> <p>Results</p> <p>R1 showed significantly increased GST-α and significantly lower GST-π levels than R2 patients or the donors. There was a positive correlation between GST-α and ALT, AST as well as bilirubin and a negative correlation to γGT. However, γGT correlated positively with GST-π. Graft failure was associated with combined low GST-π levels in donors and their recipients before living donor liver transplantation.</p> <p>Conclusion</p> <p>Our data suggest that high GST-α serum levels reflect ongoing liver damage while GST-P indicates the capacity and process of liver regeneration. Additionally, GST-π may be useful as marker for optimizing donor and recipient pairs in living donor liver transplantation.</p

    Breaking the entangling gate speed limit for trapped-ion qubits using a phase-stable standing wave

    Full text link
    All laser-driven entangling operations for trapped-ion qubits have hitherto been performed without control of the optical phase of the light field, which precludes independent tuning of the carrier and motional coupling. By placing 88^{88}Sr+^+ ions in a λ=674\lambda=674 nm standing wave, whose relative position is controlled to λ/100\approx\lambda/100, we suppress the carrier coupling by a factor of 1818, while coherently enhancing the spin-motion coupling. We experimentally demonstrate that the off-resonant carrier coupling imposes a speed limit for conventional traveling-wave M{\o}lmer-S{\o}rensen gates; we use the standing wave to surpass this limit and achieve a gate duration of $15\ \mu$s, restricted by the available laser power.Comment: S. Saner and O. B\u{a}z\u{a}van contributed equally to this wor

    Secondary Prevention Through Cardiac Rehabilitation: Position Paper of the Working Group on Cardiac Rehabilitation and Exercise Physiology of the European Society of Cardiology

    Get PDF
    The purpose of this statement is to provide specific recommendations in regard to evaluation and intervention in each of the core components of cardiac rehabilitation (CR) to assist CR staff in the design and development of their programmes; the statement should also assist health care providers, insurers, policy makers and consumers in the recognition of the comprehensive nature of such programmes. Those charged with responsibility for secondary prevention of cardiovascular disease, whether at European, at national or at individual centre level, need to consider where and how structured programmes of CR can be delivered to the large constituency of patients now considered eligible for C

    Change in adiposity is associated with change in glycoprotein acetyls but not hsCRP in adolescents with severe obesity.

    Get PDF
    BACKGROUND Obesity-associated chronic inflammation mediates the development of adverse cardiometabolic outcomes. There are sparse data on associations between severe obesity and inflammatory biomarkers in adolescence; most are cross-sectional and limited to acute phase reactants. Here, we investigate associations between adiposity measures and inflammatory biomarkers in children and adolescents with severe obesity both cross-sectionally and longitudinally. METHODS From the Childhood Overweight Biorepository of Australia (COBRA) study, a total of n = 262 participants, mean age 11.5 years (SD 3.5) with obesity had measures of adiposity (body mass index, BMI; % above the 95th BMI-centile, %>95th BMI-centile; waist circumference, WC; waist/height ratio, WtH; % total body fat, %BF; % truncal body fat, %TF) and inflammation biomarkers (glycoprotein acetyls, GlycA; high-sensitivity C-Reactive Protein, hsCRP; white blood cell count, WBC; and neutrophil/lymphocyte ratio, NLR) assessed at baseline. Ninety-eight individuals at mean age of 15.9 years (3.7) participated in a follow-up study 5.6 (2.1) years later. Sixty-two individuals had longitudinal data. Linear regression models, adjusted for age and sex for cross-sectional analyses were applied. To estimate longitudinal associations between change in adiposity measures with inflammation biomarkers, models were adjusted for baseline measures of adiposity and inflammation. RESULTS All adiposity measures were cross-sectionally associated with GlycA, hsCRP and WBC at both time points. Change in BMI, %>95th BMI-centile, WC, WtH and %TF were associated with concomitant change in GlycA and WBC, but not in hsCRP and NLR. CONCLUSION GlycA and WBC but not hsCRP and NLR may be useful in assessing adiposity-related severity of chronic inflammation over time

    From paradox to principles: where next for scientific advice to governments?

    Get PDF
    Scientific advice to governments has never been in greater demand; nor has it been more contested. From climate change to cyber-security, poverty to pandemics, food technologies to fracking, the questions being asked of scientists, engineers and other experts by policymakers, the media and the wider public continue to multiply and increase in complexity. At the same time, the authority and legitimacy of experts are under increasing scrutiny. This thematic article collection (‘special issue’) brings together perspectives on the theory, practice and politics of scientific advice that build on the conclusions of the landmark conference in Auckland in August 2014, which led to the creation of the International Network for Government Science Advice (INGSA). We hope that new papers will continue to be added to this collection over the next year and beyond, making it a living, fully open access repository for new scholarship and policy thinking—and an important contribution to the emerging science and art of scientific advice
    corecore