Nitrogen removal in maturation WSP ponds via biological uptake and sedimentation of dead biomass

In this work a set of experiments was undertaken in a pilot-scale WSP system to determine the importance of organic nitrogen sedimentation on ammonium and total nitrogen removals in maturation ponds and its seasonal variation under British weather conditions. Two maturation ponds in series (M1 and M2) were monitored seasonally from September 2004 to May 2007. The nitrogen content in collected sediment samples varied from 4.17 to 6.78 percent (dry weight) and calculated nitrogen sedimentation rates ranged from 291 to 2,868 g N/ha d in M1 and from 273 to 2,077 g N/ha d in M2. The increment of chlorophyll-a in M1 and M2 maturation pond effluents had a very good correlation with the corresponding increment of VSS (algal biomass) and suspended organic nitrogen; therefore, the occurrence of biological (algal) nitrogen uptake was confirmed. After sedimentation of the dead algal biomass, it was clear that algal-cell nitrogen was recycled from the sludge layer into the pond water column. An important portion (51% in M1 and 39% in M2) of the nitrogen taken up by the in-pond algae was finally accumulated as sludge after anaerobic digestion. Biological (mainly algal) uptake of inorganic nitrogen species and further sedimentation of dead biomass is one of the major mechanisms controlling ammonium and nitrogen removal in maturation WSP, particularly when environmental and operational conditions are favourable for algal growth

Fire-mediated germination syndromes in Leucadendron (Proteaceae) and their functional correlates

A mechanistic understanding of fire-driven seedling recruitment is essential for effective conservation management of fire-prone vegetation, such as South African fynbos, especially with rare and threatened taxa. The genus Leucadendron (Proteaceae) is an ideal candidate for comparative germination studies, comprising 85 species with a mixture of contrasting life-history traits (killed by fire vs able to resprout; serotinous vs geosporous) and seed morphologies (nutlets vs winged achenes). Individual and combined effects of heat and smoke on seed germination of 40 species were quantified in the laboratory, and Bayesian inference applied to distinguish biologically meaningful treatment effects from non-zero, but biologically trivial, effects. Three germination syndromes were identified based on whether germination was dependent on, enhanced by, or independent of direct fire cues (heat and smoke). Seed storage location was the most reliable predictor of germination syndromes, with soil-stored seeds c. 80% more likely to respond to direct fire cues (primarily smoke) than canopy-stored seeds. Notable exceptions were L. linifolium, with an absolute requirement for smoke to germinate (the third serotinous species so reported), and two other serotinous species with smoke-enhanced germination. Nutlet-bearing species, whether serotinous or geosporous, were c. 70% more likely to respond to fire cues than winged seeds, but there was no evidence for an effect of phylogeny or persistence strategy on germination. This comprehensive account of seed germination characteristics and identification of germination syndromes and their predictors, supports propagation, conservation and restoration initiatives in this iconic fynbos genus and other fire-prone shrubs with canopy or soil-stored seeds

Introduced species infiltrate early stages of succession after glacial retreat on sub-Antarctic South Georgia

Biological invasions are one of the main drivers of global biodiversity decline. At the same time, glacial retreat induced by climate warming is occurring at an alarming rate across the globe, threatening unique taxa and ecosystems. However, we know little about how introduced species contribute to the dynamics of colonisation in newly-deglaciated forelands. To answer this question, detailed inventories of plant and invertebrate communities were undertaken during two summer field seasons in the forelands of three tidewater and three inland glaciers that are retreating on the sub-Antarctic Island of South Georgia. The vascular plant communities present included a large proportion of South Georgia’s native flora. As expected, plant richness and cover increased with time since deglaciation along a deglaciation chronosequence. Introduced plants were well represented in the study sites and two species (Poa annua and Cerastium fontanum) were amongst the earliest and most frequent colonisers of recently-deglaciated areas (occurring on more than 75% of transects surveyed). Introduced arthropods were also present around tidewater glaciers, including an important predatory species (Merizodus soledadinus) with known detrimental impacts on native invertebrate communities. Our study provides a rare and detailed picture of developing novel communities along a deglaciation chronosequence in the sub-Antarctic. Introduced species are able to track glacial retreat on South Georgia, indicating that further local colonisation and spread are inevitable as the region’s climate continues to warm

Approaches to Address Premature Death of Patients When Assessing Patterns of Use of Health Care Services after an Index Event

Background: Studies of the use of health care after the onset of disease are important for assessing quality of care, treatment disparities, and guideline compliance. Cohort definition and analysis method are important considerations for the generalizability and validity of study results. We compared different approaches for cohort definition (restriction by survival time vs. comorbidity score) and analysis method [Kaplan-Meier (KM) vs. competing risk] when assessing patterns of guideline adoption in elderly patients. Methods: Medicare beneficiaries aged 65-95 years old who had an acute myocardial infarction (AMI) in 2008 were eligible for this study. Beneficiaries with substantial frailty or an AMI in the prior year were excluded. We compared KM with competing risk estimates of guideline adoption during the first year post-AMI. Results: At 1-year post-AMI, 14.2% [95% confidence interval (CI), 14.0%-14.5%) of beneficiaries overall initiated cardiac rehabilitation when using competing risk analysis and 15.1% (95% CI, 14.8%-15.3%) from the KM analysis. Guideline medication adoption was estimated as 52.3% (95% CI, 52.0%-52.7%) and 53.4% (95% CI, 53.1%-53.8%) for competing risk and KM methods, respectively. Mortality was 17.0% (95%CI, 16.8%-17.3%) at 1 year post-AMI. The difference in cardiac rehabilitation initiation at 1-year post-AMI from the overall population was 0.1%, 1.7%, and 1.9% compared with 30-day survivor, 1-year survivor, and comorbidity-score restricted populations, respectively. Conclusions: In this study, the KM method consistently overestimated the competing risk method. Competing risk approaches avoid unrealistic mortality assumptions and lead to interpretations of estimates that are more meaningful

Prescission neutron multiplicity and fission probability from Langevin dynamics of nuclear fission

A theoretical model of one-body nuclear friction which was developed earlier, namely the chaos-weighted wall formula, is applied to a dynamical description of compound nuclear decay in the framework of the Langevin equation coupled with statistical evaporation of light particles and photons. We have used both the usual wall formula friction and its chaos-weighted version in the Langevin equation to calculate the fission probability and prescission neutron multiplicity for the compound nuclei $^{178}$W, $^{188}$Pt, $^{200}$Pb, $^{213}$Fr, $^{224}$Th, and $^{251}$Es. We have also obtained the contributions of the presaddle and postsaddle neutrons to the total prescission multiplicity. A detailed analysis of our results leads us to conclude that the chaos-weighted wall formula friction can adequately describe the fission dynamics in the presaddle region. This friction, however, turns out to be too weak to describe the postsaddle dynamics properly. This points to the need for a suitable explanation for the enhanced neutron emission in the postsaddle stage of nuclear fission.Comment: RevTex, 14 pages including 5 Postscript figures, results improved by using a different potential, conclusions remain unchanged, to appear in Phys. Rev.

Temperature and Photoperiod Effects on Sterility in a Cytoplasmic Male-Sterile Soybean

Manual cross-pollination to produce large quantities of hybrid soybean seed is difficult and time consuming. An environmentally stable sterility system is one of the necessary components to produce large quantities of hybrid seed. The objective of this study was to subject cytoplasmic male-sterile (CMS) BC5F1 plants, from a cross of a Chinese Glycine max wild-type soybean with a Chinese wild annual soybean G. soja (male parent) and controls, to a variety of different temperature and photoperiod treatments to test whether CMS is stable under various environmental conditions. Plants were grown in growth chambers under controlled temperature, photoperiod, and irradiance regimes until pod set, and then they were transferred to a glasshouse until they matured. Plants were evaluated for time of anthesis after photoperiod induction (13 h light/11 h dark) and fertility or sterility. Anther squash and pod set data showed that sterility of the CMS line was stable under all environmental conditions tested, whereas fertility-restored control plants remained fertile. Extreme environmental conditions led to delayed floral induction and/or stunted growth

Temporal Trends and Prognosis of Physical Examination Findings in Patients with Acute Decompensated Heart Failure: The ARIC Study Community Surveillance

BACKGROUND: Bedside evaluation of congestion is a mainstay of heart failure (HF) management. Whether detected physical examination signs have changed over time as obesity prevalence has increased in HF populations, or if the associated prognosis differs for HF with reduced or preserved ejection fraction (HFrEF or HFpEF) is uncertain. METHODS: From 2005 to 2014, the ARIC study (Atherosclerosis Risk in Communities) conducted adjudicated hospital surveillance of acute decompensated HF. We analyzed trends in physical examination findings, imaging signs, and symptoms related to congestion, both over time and by obesity class, and associated 28-day mortality risks. RESULTS: Of 24 937 weighted hospitalizations for acute decompensated HF (mean age 75 years, 53% women, 32% Black), 47% had HFpEF. The prevalence of obesity increased from 2005 to 2014 for both HF types. With increasing obesity category, detected edema increased, while jugular venous distension decreased, and rales remained stable. Detected edema also increased over time, for both HF types. Associations between 28-day mortality and individual signs and symptoms of congestion were similar for HFpEF and HFrEF; however, the adjusted mortality risk with all 3 (edema, rales, and jugular venous distension) versus <3 physical examination findings was higher for patients with HFpEF (odds ratio, 2.41 [95% CI, 1.53-3.79]) than HFrEF (odds ratio, 1.30 [95% CI, 0.87-1.93]); P for interaction by HF type =0.02. CONCLUSIONS: In patients hospitalized with acute decompensated HF, detected physical examination findings differ both temporally and by obesity. Combined findings from the physical examination are more prognostic of 28-day mortality for patients with HFpEF than HFrEF

Life path analysis: scaling indicates priming effects of social and habitat factors on dispersal distances

1. Movements of many animals along a life-path can be separated into repetitive ones within home ranges and transitions between home ranges. We sought relationships of social and environmental factors with initiation and distance of transition movements in 114 buzzards Buteo buteo that were marked as nestlings with long-life radio tags. 2. Ex-natal dispersal movements of 51 buzzards in autumn were longer than for 30 later in their first year and than 35 extra-natal movements between home ranges after leaving nest areas. In the second and third springs, distances moved from winter focal points by birds that paired were the same or less than for unpaired birds. No post-nuptial movement exceeded 2 km. 3. Initiation of early ex-natal dispersal was enhanced by presence of many sibs, but also by lack of worm-rich loam soils. Distances travelled were greatest for birds from small broods and with relatively little short grass-feeding habitat near the nest. Later movements were generally enhanced by the absence of loam soils and short grassland, especially with abundance of other buzzards and probable poor feeding habitats (heathland, long grass). 4. Buzzards tended to persist in their first autumn where arable land was abundant, but subsequently showed a strong tendency to move from this habitat. 5. Factors that acted most strongly in ½-km buffers round nests, or round subsequent focal points, usually promoted movement compared with factors acting at a larger scale. Strong relationships between movement distances and environmental characteristics in ½-km buffers, especially during early ex-natal dispersal, suggested that buzzards became primed by these factors to travel far. 6. Movements were also farthest for buzzards that had already moved far from their natal nests, perhaps reflecting genetic predisposition, long-term priming or poor habitat beyond the study area

HI in the Outskirts of Nearby Galaxies

The HI in disk galaxies frequently extends beyond the optical image, and can trace the dark matter there. I briefly highlight the history of high spatial resolution HI imaging, the contribution it made to the dark matter problem, and the current tension between several dynamical methods to break the disk-halo degeneracy. I then turn to the flaring problem, which could in principle probe the shape of the dark halo. Instead, however, a lot of attention is now devoted to understanding the role of gas accretion via galactic fountains. The current $\rm \Lambda$ cold dark matter theory has problems on galactic scales, such as the core-cusp problem, which can be addressed with HI observations of dwarf galaxies. For a similar range in rotation velocities, galaxies of type Sd have thin disks, while those of type Im are much thicker. After a few comments on modified Newtonian dynamics and on irregular galaxies, I close with statistics on the HI extent of galaxies.Comment: 38 pages, 17 figures, invited review, book chapter in "Outskirts of Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and Space Science Library, Springer, in pres

Peatland afforestation in the UK and consequences for carbon storage

Peatlands are a globally significant store of carbon. During the second half of the 20th century new planting techniques combined with tax incentives encouraged commercial forestry across large areas of peat bog in the UK, particularly in the Flow Country of northern Scotland. Such planting was controversial and was ultimately halted by removal of the tax incentives, and policies to prevent new planting. Here we review the literature on UK peatland afforestation in relation to carbon and climate implications, and identify key issues for future research. The effects of conifer planting on peat bog carbon storage in the UK are poorly understood. A large body of research on peatland forestry exists, particularly from naturally forested fen peatlands in Fennoscandia and Russia, but the different conditions in the UK mean that results are not directly transferable. Data on the responses of UK peat bogs to afforestation are required to address this shortfall. Studies are required that quantify the loss of carbon from the peat and evaluate it against the accumulation of carbon above and below ground in trees, considering the likely residence time of carbon in wood products