Grazing and topography control nutrient pools in low Arctic soils of Southwest Greenland.

Soil nutrient pools in the dry low Arctic are likely to be released under climatic change and this bioavailability has the potential to increase both terrestrial and aquatic productions. As well as the direct effect of warming, external disturbances such as nutrient deposition and grazing can also drive ecosystem change. This study in the low Arctic Kangerlussuaq area of southwest Greenland compared soil nutrient pools in terms of both topographic position on a catena and by soil depth in two small catchments with contrasting muskox abundance. We tested the hypotheses that there were differences between soil carbon (C), nitrogen (N) and phosphorus (P) across a soil catena (ridge - slope - valley) and by soil depth (litter - 0-5 cm - 25-30 cm) for the two sites (SS17b, muskox present, versus - SS85, no muskox). Total C and N concentrations of soils were on average lower at SS17b compared to SS85. Moreover, the soil N concentration increased downslope in the catena with higher amounts in the valleys compared to the slopes and ridges. Soil P concentration (0.70 g P kg-1) was similar between catchments; however, litter P content was substantially different. The difference in soil nutrients between the two catchments was most likely due to the presence of muskox at SS17b, and hence grazing associated processes (defecation, altered microbiology and nutrient cycling). This study emphasises the heterogeneity of arctic landscapes and need for ecosystem specific research. Highlights: Soil nutrient pools in two low-arctic catchments in Greenland were compared.Grazing and dung inputs by muskox affect soil nutrient pools in Greenland.Soil P stores in Kangerlussuaq are similar to intensively managed farmland in Europe.The heterogeneity of arctic landscapes and need for ecosystem-specific research are emphasised.

Isotopic evidence of biotrophy and unusual nitrogen nutrition in soil-dwelling Hygrophoraceae.

Several lines of evidence suggest that the agaricoid, non-ectomycorrhizal members of the family Hygrophoraceae (waxcaps) are biotrophic with unusual nitrogen nutrition. However, methods for the axenic culture and lab-based study of these organisms remain to be developed, so our current knowledge is limited to field-based investigations. Addition of nitrogen, lime or organophosphate pesticide at an experimental field site (Sourhope) suppressed fruiting of waxcap basidiocarps. Furthermore, stable isotope natural abundance in basidiocarps were unusually high in 15 N and low in 13 C, the latter consistent with mycorrhizal nutritional status. Similar patterns were found in waxcap basidiocarps from diverse habitats across four continents. Additional data from 14 C analysis of basidiocarps and 13 C pulse label experiments suggest that these fungi are not saprotrophs but rather biotrophic endophytes and possibly mycorrhizal. The consistently high but variable δ15 N values (10-20‰) of basidiocarps further indicate that N acquisition or processing differ from other fungi; we suggest that N may be derived from acquisition of N via soil fauna high in the food chain.

Efficacy and duration of response to botulinum neurotoxin A (onabotulinumA) as a treatment for detrusor overactivity in women.

INTRODUCTION AND HYPOTHESIS: Overactive bladder syndrome with urinary incontinence has a number of treatment options. The National Institute for Health and Care Excellence (NICE) in the UK, the American Urological Association (AUA) and the European Association of Urology (EAU) recommend intradetrusor botulinum neurotoxin A (onabotulinumA) injections in women with proven detrusor overactivity (DO) in whom conservative therapies have failed to improve symptoms. However, the effects of individual onabotulinumA treatments are of short duration and patients usually require further treatments. There is little evidence to inform long-term management strategies using onabotulinumA for DO. METHODS: A retrospective review of patients receiving intradetrusor onabotulinumA injections for DO over a 7-year period was conducted. The primary outcome measures included patient's subjective reports of symptom change following injections (efficacy) and the duration of symptomatic relief following each treatment. RESULTS: The analysis included 136 patients. The mean time between patients receiving intradetrusor onabotulinumA and being added to the surgical waiting list for re-treatment varied between 8.5 and 10.4 months for the first five cycles of treatment with the longest time between the third and fourth cycles. This decreased to 5.5 and 5.25 (ANOVA p = 0.015) between the fifth and sixth cycles and between the sixth and seventh cycles of treatment, respectively. Only 19.9% of patients continued treatment beyond this, with four patients receiving a seventh treatment. CONCLUSIONS: Our results suggest that in patients who respond to onabotulinumA treatment, the duration of response declines after the fifth treatment, suggesting a possible tolerance effect and a subsequent decline in efficacy.

Study protocol for a randomized controlled trial comparing the efficacy of a specialist and a generic parenting programme for the treatment of preschool ADHD.

BACKGROUND: The New Forest Parenting Programme (NFPP) is a home-delivered, evidence-based parenting programme to target symptoms of attention-deficit/hyperactivity disorder (ADHD) in preschool children. It has been adapted for use with 'hard-to-reach' or 'difficult-to-treat' children. This trial will compare the adapted-NFPP with a generic parenting group-based programme, Incredible Years (IY), which has been recommended for children with preschool-type ADHD symptoms. METHODS/DESIGN: This multicentre randomized controlled trial comprises three arms: adapted-NFPP, IY and treatment as usual (TAU). A sample of 329 parents of preschool-aged children with a research diagnosis of ADHD enriched for hard-to-reach and potentially treatment-resistant children will be allocated to the arms in the ratio 3:3:1. Participants in the adapted-NFPP and IY arms receive an induction visit followed by 12 weekly parenting sessions of 1½ hours (adapted-NFPP) or 2½ hours (IY) over 2.5 years. Adapted-NFPP will be delivered as a one-to-one home-based intervention; IY, as a group-based intervention. TAU participants are offered a parenting programme at the end of the study. The primary objective is to test whether the adapted-NFPP produces beneficial effects in terms of core ADHD symptoms. Secondary objectives include examination of the treatment impact on secondary outcomes, a study of cost-effectiveness and examination of the mediating role of treatment-induced changes in parenting behaviour and neuropsychological function. The primary outcome is change in ADHD symptoms, as measured by the parent-completed version of the SNAP-IV questionnaire, adjusted for pretreatment SNAP-IV score. Secondary outcome measures are: a validated index of behaviour during child's solo play; teacher-reported SNAP-IV (ADHD scale); teacher and parent SNAP-IV (ODD) Scale; Eyberg Child Behaviour Inventory - Oppositional Defiant Disorder scale; Revised Client Service Receipt Inventory - Health Economics Costs measure and EuroQol (EQ5D) health-related quality-of-life measure. Follow-up measures will be collected 6 months after treatment for participants allocated to adapted-NFPP and IY. DISCUSSION: This trial will provide evidence as to whether the adapted-NFPP is more effective and cost-effective than the recommended treatment and TAU. It will also provide information about mediating factors (improved parenting and neuropsychological function) and moderating factors (parent and child genetic factors) in any increased benefit. TRIAL REGISTRATION: Current Controlled Trials, ISRCTN39288126.

RCT of urethral versus suprapubic catheterization.

OBJECTIVE: To compare the use of intermittent urethral catheterization with indwelling suprapubic catheterization in women undergoing surgery for urodynamic stress incontinence or uterovaginal prolapse. DESIGN: Randomized controlled trial. SETTING: Tertiary referral urogynaecology unit. POPULATION: Women undergoing surgery for pelvic organ prolapse and/or stress urinary incontinence. METHODS: Women were randomized into one of two groups. Group 1 had bladder drainage using a suprapubic catheter inserted in theatre. The catheter was left on free drainage for 48 hours post-operatively before clamping. Group 2 was catheterized intermittently post-operatively. MAIN OUTCOME MEASURES: Length of post-operative hospital stay: time to resume normal voiding (defined as voided volumes greater than 200 mls and residual urine volumes less than 100 mls on three occasions); number of urinary tract infections (UTIs); catheterization costs; patient experience (determined from questionnaire); and a pain score. RESULTS: 75 women were randomized; 38 to suprapubic catheterization; 37 to intermittent catheterization. Three were withdrawn from study, leaving 36 women in each group. Groups were closely matched for age and type of surgery undertaken. Length of hospital stay and total duration of catheterization were both significantly shorter for the intermittent catheterization group; although there was no difference in the rate of UTI between the two groups. There was no clear patient preference for a specific catheterization method. CONCLUSIONS: The use of intermittent catheterization following urogynaecological surgery is associated with a more rapid return to normal micturition and a shorter hospital stay, although the clinical significance of the difference is perhaps limited.

Short term N2O, CH4 and CO2 production from soil sampled at different depths and amended with a fine sized slurry fraction.

Little is known about the interaction of the soil's physicochemical environment and livestock slurry throughout the soil profile. In this study, five soil layers (2-6, 6-10, 10-14, 14-18, 18-22 cm) amended with a<45 microm slurry fraction (FS) or water (control) were incubated for 58 d at 20 degrees C to determine the effect of the slurry position in the soil profile on the production of CO(2), N(2)O, CH(4) and total greenhouse gas (GHG) expressed as CO(2) equivalent. FS application increased the CO(2) production in all soil layers by 3-8 times compared to the controls. The total CO(2) produced during the incubation in the 2-6 cm amended soil layer (>1,600 mg CO(2)-C kg(-1) dry soil) was significantly greater (P<0.05) than in other amended layers (<800 mg CO(2)-C kg(-1) dry soil). No detectable N(2)O production was observed from control treatments, and application of FS induced a slow increase in N(2)O production. N(2)O production occurred earlier and at a higher rate in deeper soil layers. Furthermore, a good correlation (r=0.899, P<0.05) was observed between N(2)O production and soil depth. The higher N(2)O production in the deeper soil layers could have been due to enhanced denitrification promoted by a lower aeration and low soil respiration in the deep soil. At the end of the incubation, >11% of the total applied N was lost as N(2)O from the two deeper soil layers against 2.5-5% in all other soil layers. Methane production was only observed from FS amended treatments within the first 7d (range 0.02-0.41 mg C kg(-1) soil d(-1)). The greatest net production of GHGs, expressed as CO(2) equivalents, was observed from the two deeper soil layers ( approximately 4.5 CO(2) eq kg(-1) soil). N(2)O and CO(2) contributed equally (50%) to the total GHG production in 2-14 cm soil layers, whereas N(2)O contributed reached 80% to the total GHG production in the deeper soil layers. The CH(4) contribution was not significant in any treatment.

Assessing multiple novel tracers to improve the understanding of the contribution of agricultural farm waste to diffuse water pollution.

A study was undertaken on drained and undrained 1 ha grassland lysimeters to assess the effectiveness of multiple novel tracing techniques in understanding how agricultural slurry waste moves from land to water. Artificial fluorescent particles designed to mimic the size and density of organic slurry particles were found to move off the grassland via inter-flow (surface + lateral through-flow) and drain-flow. Where both pathways were present the drains carried the greater number of particles. The results of the natural fluorescence and δ13C of water samples were inconclusive. Natural fluorescence was higher from slurry-amended lysimeters than from zero-slurry lysimeters, however, a fluorescence decay experiment suggested that no slurry signal should be present given the time between slurry application and the onset of drainage. The δ13C values of >0.7 microm and <0.7 microm material in drainage were varied and unrelated to discharge. The mean value of >0.7 microm δ13C in water from the drain-flow pathways was higher from the lysimeter which had received naturally enriched maize slurry compared to the lysimeter which received grass slurry indicating a contribution of slurry-derived material. Values of <0.7 microm δ13C from the same pathway, however, produced counter intuitive trends and may indicate that different fractions of the slurry have different δ13C values.

Large old trees influence patterns of delta13C and delta15N in forests.

Large old trees are the dominant primary producers of native pine forest, but their influence on spatial patterns of soil properties and potential feedback to tree regeneration in their neighbourhood is poorly understood. We measured stable isotopes of carbon (delta(13)C) and nitrogen (delta(15)N) in soil and litter taken from three zones of influence (inner, middle and outer zone) around the trunk of freestanding old Scots pine (Pinus sylvestris L.) trees, to determine the trees' influence on below-ground properties. We also measured delta(15)N and delta(13)C in wood cores extracted from the old trees and from regenerating trees growing within their three zones of influence. We found a significant and positive gradient in soil delta(15)N from the inner zone, nearest to the tree centre, to the outer zone beyond the tree crown. This was probably caused by the higher input of (15)N-depleted litter below the tree crown. In contrast, the soil delta(13)C did not change along the gradient of tree influence. Distance-related trends, although weak, were visible in the wood delta(15)N and delta(13)C of regenerating trees. Moreover, the wood delta(15)N of small trees showed a weak negative relationship with soil N content in the relevant zone of influence. Our results indicate that large old trees control below-ground conditions in their immediate surroundings, and that stable isotopes might act as markers for the spatial and temporal extent of these below-ground effects.

Long-term influence of manure and mineral nitrogen applications on plant and soil 15N and 13C values from the Broadbalk Wheat Experiment.

The Broadbalk Wheat Experiment at Rothamsted Research in the UK provides a unique opportunity to investigate the long-term impacts of environmental change and agronomic practices on plants and soils. We examined the influence of manure and mineral fertiliser applications on temporal trends in the stable N ((15)N) and C ((13)C) isotopes of wheat collected during 1968-1979 and 1996-2005, and of soil collected in 1966 and 2000. The soil delta(15)N values in 1966 and 2000 were higher in manure than the mineral N supplied soil; the latter had similar or higher delta(15)N values than non-fertilised soil. The straw delta(15)N values significantly decreased in all N treatments during 1968 to 1979, but not for 1996-2005. The straw delta(15)N values decreased under the highest mineral N supply (192 kg N ha(-1) year(-1)) by 3 per thousand from 1968 to 1979. Mineral N supply significantly increased to straw delta(13)C values in dry years, but not in wet years. Significant correlations existed between wheat straw delta(13)C values with cumulative rainfall (March to June). The cultivar Hereward (grown 1996-2005) was less affected by changes in environmental conditions (i.e. water stress and fertiliser regime) than Cappelle Desprez (1968-1979). We conclude that, in addition to fertiliser type and application rates, water stress and, importantly, plant variety influenced plant delta(13)C and delta(15)N values. Hence, water stress and differential variety response should be considered in plant studies using plant delta(13)C and delta(15)N trends to delineate past or recent environmental or agronomic changes.

Use of carbon isotope analysis to understand semi-arid erosion dynamics and long-term semi-arid land degradation.

Many semi-arid areas worldwide are becoming degraded, in the form of C(4) grasslands being replaced by C(3) shrublands, which causes an increase in surface runoff and erosion, and altered nutrient cycling, which may affect global biogeochemical cycling. The prevention or control of vegetation transitions is hindered by a lack of understanding of their temporal and spatial dynamics, particularly in terms of interactions between biotic and abiotic processes. This research investigates (1) the effects of soil erosion on the delta(13)C values of soil organic matter (SOM) throughout the soil profile and its implications for reconstructing vegetation change using carbon-isotope analysis and (2) the spatial properties of erosion over a grass-shrub transition to increase understanding of biotic-abiotic interactions by using delta(13)C signals of eroded material as a sediment tracer. Results demonstrate that the soils over grass-shrub transitions are not in steady state. A complex interplay of factors determines the input of SOM to the surface horizon of the soil and its subsequent retention and turnover through the soil profile. A positive correlation between event runoff and delta(13)C signatures of eroded sediment was found in all plots. This indicates that the delta(13)C signatures of eroded sediment may provide a means of distinguishing between changes in erosion dynamics over runoff events of different magnitudes and over different vegetation types. The development of this technique using delta(13)C signatures of eroded sediment provides a new means of furthering existing understanding of erosion dynamics over vegetation transitions. This is critical in terms of understanding biotic-abiotic feedbacks and the evolution of areas subject to vegetation change in semi-arid environments.