Search

Time series of wetland methane fluxes measured by eddy covariance require gap-filling to estimate daily, seasonal, and annual emissions. Gap-filling methane fluxes is challenging because of high variability and complex responses to multiple drivers. To date, there is no widely established gap-filling standard for wetland methane fluxes, with regards both to the best model algorithms and predictors. This study synthesizes results of different gap-filling methods systematically applied at 17 wetland sites spanning boreal to tropical regions and including all major wetland classes and two rice paddies. Procedures are proposed for: 1) creating realistic artificial gap scenarios, 2) training and evaluating gap-filling models without overstating performance, and 3) predicting half-hourly methane fluxes and annual emissions with realistic uncertainty estimates. Performance is compared between a conventional method (marginal distribution sampling) and four machine learning algorithms. The conventional method achieved similar median performance as the machine learning models but was worse than the best machine learning models and relatively insensitive to predictor choices. Of the machine learning models, decision tree algorithms performed the best in cross-validation experiments, even with a baseline predictor set, and artificial neural networks showed comparable performance when using all predictors. Soil temperature was frequently the most important predictor whilst water table depth was important at sites with substantial water table fluctuations, highlighting the value of data on wetland soil conditions. Raw gap-filling uncertainties from the machine learning models were underestimated and we propose a method to calibrate uncertainties to observations. The python code for model development, evaluation, and uncertainty estimation is publicly available. This study outlines a modular and robust machine learning workflow and makes recommendations for, and evaluates an improved baseline of, methane gap-filling models that can be implemented in multi-site syntheses or standardized products from regional and global flux networks (e.g., FLUXNET). ISSN:0168-1923 ISSN:1873-2240

Management of agricultural grasslands can alter soil carbon (C) stocks, and quantifying the effects of different management regimes is important to inform global greenhouse gas (GHG) mitigation strategies. Here, we report the net ecosystem carbon balance (NECB) over three years for an intensively managed rotationally grazed New Zealand dairy farm importing 11.6 t DM ha−1 y−1 (526 g C m−2 y−1) as supplemental feed. We investigated whether importing large quantities of supplemental feed to increase milk production led to a gain in soil C. Eddy covariance measurements were used to quantify net ecosystem productivity (NEP), with all other imports and exports of C calculated from farm records and measurements. Additionally, we compared the NECB calculated with a system boundary equivalent to the farm boundary (NECBFarm), to that calculated with the system boundary around the paddocks in which the EC footprint extended (NECBFootprint). Both the three-year average NECBFarm and NECBFootprint were similar, but could not be distinguished from zero (71 ± 77 g C m−2 y−1 and 56 ± 77 g C m−2 y−1, respectively; uncertainties are standard deviations). The farm boundary approach made better use of available C import and export data (excluding NEP) data, however, error propagation resulted in almost identical uncertainties of the C balance for both methods. Supplementary feed was the major C input of NECBFarm but was only a minor component of NECBFootprint due to the use of a dedicated feed pad outside of the NECBFootprint boundary. In contrast, transfer of C from excreta (including that resulting from the supplementary feed consumed on the feed pad) was the major C input of NECBFootprint. Consumption of the supplementary feed by grazing animals resulted in most of the imported C exiting the system boundary via pathways that included the export of product (milk), respiration of CO2 and methane production. Only the imported supplementary feed C excreted by the grazing animals along with the C in any feed that was wasted was available for sequestration. When coupled with manure C retention coefficients only a small gain in soil C could be expected. Our result demonstrated that importation of a large quantity of supplemental feed C did not lead to a large gain in soil C. Production of supplemental feed off site likely contributed to considerable GHG production and full life-cycle assessment is needed to determine the overall consequence of increasing milk production with supplemental feed.

Introductions Over The Scope Clips (OTSC)® have developed valuable indications in adult endoscopy. These indications include: non-variceal gastrointestinal (GI) bleeding, anastomotic bleeding, closure of fistulae such as gastro-cutaneous and post-gastrostomypersistent fistulae closure. Different clip sizes are available, the smallest being 8.5–9.8 mm in diameter with its loading device on the tip of the endoscope increasing the device and endoscope intubation diameter to 14.6 mm. This may present challenges in terms of the size of the patient in whom it might be used. OTSC® appear effective and safe when appropriate training is received in adult interventional endoscopy. There are no reported case series of OTSC® in children. We undertook a service evaluation of our recent experience with this technology in a regional/national referral paediatric endoscopy unit. Methods The hospital database was searched to identify cases where OTSC® was used for indications other than acute non-variceal GI bleeding. A retrospective collection of data including demographics, presentation, anthropometry, co-morbidities, efficacy and complications was done. Post-procedure follow up was identified in the clinic or in-patient setting. Special emphasis was laid on resolution or recurrence of the original indication, and any complications related to the procedure. Results Seven patients (3 male) were identified in whom the OTSC® procedure had been performed between February 2018 and February 2020. Median age was 10.8 (range 5.2–16.6) years. Median weight was 27.08 (range 18.2–44.3) kg. The patient profile, indications for the procedure and the outcome are detailed in table 1. Successful outcome was achieved in 5/7 patients and a complication of an oesophageal perforation occurred in 1/7 which healed without surgical intervention. Conclusion The OTSC® device appears effective in a limited number of situations in older and larger children including anastomotic ulcers, closure of leaking percutaneous endoscopic gastrostomy (PEG) fistula/site following removal, gastric perforation and bleeding peptic ulcers. The operator should be an experienced endo-therapeutic endoscopist with specific OTSC® training, and the type and size of the OTSC® device should be carefully considered, along with any co-morbidities of the patient that may preclude success and/or lead to potential complications such as oesophageal perforation.

Reflux disease can be overt (with vomiting) or silent. A range of symptoms affecting the aero-digestive tract can be attributed to GORD. This chapter highlights that range of symptoms and the range of associated medical conditions that lead to GORD. Treatment involves considering associated cow’s milk allergy in young infants and treatment with antacids.

Projections indicate that climate change may exacerbate existing challenges to the productivity of New Zealand dairy farming systems. To assess the importance of these projections and understand adaptation challenges at farm level, detailed farm-scale model simulations of climate change impacts were undertaken for six representative pasture-based dairy farms located in the major dairying regions of New Zealand. The analysis suggested that without adaptation, climate change is likely to have a negative impact in most of the study locations. However, the level and type of impact depends to a large degree on regional climate variability as well as on the management practices of each farm. Under current management, responses to projected climate changes ranged from no change to an 18% decrease in average annual pasture production. A number of modelled adaptations demonstrated the potential to reduce climate change impacts under current management. The modelling work, together with farmers' responses, showed the adaptations' potential to provide both benefits and management challenges across different regions and climate conditions. In particular, it highlighted the need for the results of farm systems modelling under climate change scenarios to be considered in the context of their specific and localised climatic and management challenges.

Pasture renewal (or pasture renovation) is a common management practice in grass-based production systems aimed at restoring pasture production and forage quality. It is important to understand the impact of pasture renewal on soil organic carbon stocks. Here we report the CO2 and C balance of three blocks of an intensively managed temperate grassland in New Zealand. Two blocks underwent pasture renewal using the spray and direct drill approach (no ploughing), while the third block served as an undisturbed Control. Net ecosystem production (NEP) was measured using eddy covariance, and additional in- and outputs of C (e.g. C in pasture removed by grazers and returned in dung) either measured or estimated. NEPs of the renewed blocks were between 149 and 212 g C m−2 y−1 lower than the NEP of the Control block during the year of pasture renewal. While CO2 sink strength was obviously diminished as a result of pasture renewal, neither renewed block was a source for CO2, presumably due the relatively warm climate which enabled year-round growing conditions. Despite the non-negative NEPs during the year of pasture renewal, both renewed sites were found to lose soil C as indicated by the negative net ecosystem carbon balances (NECBs). NECBs of the renewed blocks were −156 and −222 g C m−2 y−1, compared to a near-neutral NECB of the Control block. Comparison of the findings from the current study on pasture renewal without ploughing to those from an earlier study on pasture renewal including ploughing led to the following conclusions: i) our data did not suggest lower rates of respiratory CO2 losses when spray-and-direct-drill approach was used instead of ploughing; ii) as both the direct CO2 losses due to microbial degradation and the decrease in CO2 uptake through photosynthesis contribute to the total impact of pasture renewal on NEP, the duration of fallow period was found to be important in determining the short-term CO2 losses due to pasture renewal, with shorter fallow period leading to lower net CO2 losses; iii) addition of C in the form of manure, effluent, or extra supplemental feed for cattle may help to reduce the negative impact of pasture renewal on soil C loss at the renewed site.

Background Cyclical vomiting syndrome is a disorder characterised by recurrent episodes of profuse vomiting. There are no cases in the literature on the management of children with presenting with cyclical vomiting syndrome and a Chiari malformation type I. Discussion We report the case of a 12-year-old child diagnosed with cyclical vomiting syndrome and a Chiari malformation type I. The patient received symptomatic relief following a craniocervical decompression.

The drainage and conversion of peatlands to productive agro-ecosystems leads to ongoing surface subsidence because of densification (shrinkage and consolidation) and oxidation of the peat substrate. Knowing the ra0te of this surface subsidence is important for future land-use planning, carbon accounting, and economic analysis of drainage and pumping costs. We measured subsidence rates over the past decade at 119 sites across three large, agriculturally managed peatlands in the Waikato region, New Zealand. The average contemporary (2000s–2012) subsidence rate for Waikato peatlands was 19 ± 2 mm yr⁻¹ (± SE) and was significantly less (p = 0.01) than the historic rate of 26 ± 1 mm yr⁻¹ between the 1920s and 2000s. A reduction in the rate of subsidence through time was attributed to the transition from rapid initial consolidation and shrinkage to slower, long-term, ongoing oxidation. These subsidence rates agree well with a literature synthesis of temperate zone subsidence rates reported for similar lengths of time since drainage. A strong nonlinear relationship was found between temperate zone subsidence rates and time since initial peatland drainage: Subsidence (mm yr⁻¹) = 226 × (years since drained)⁻⁰.⁵⁹ (R² = 0.88). This relationship suggests that time since drainage exerts strong control over the rate of peatland subsidence and that ongoing peatland subsidence rates can be predicted to gradually decline with time in the absence of major land disturbance.

It is well known that frequent cultivation of cropped soils leads to increased soil respiration and loss of soil carbon (C). In contrast, little is known about the impact of occasional cultivation of permanent grasslands on soil C and CO2 dynamics. Occasional cultivation of pastures is common if a pasture is part of an arable-ley rotation, or as part of pasture renewal. Here we report on the CO2 balance following three cultivation events of temperate permanent pasture in New Zealand. For two experiments, one during a drought during late summer/autumn 2008 and one under moist soil conditions in spring 2008, CO2 losses following cultivation were measured using the closed chamber technique. During the spring 2008 experiment, two soils with different clay mineralogy and drainage were studied. During a third cultivation event in autumn 2010 CO2 exchange was measured using eddy covariance. Measured short-term respiratory losses following cultivation across the three experiments ranged from 151 to 329 g C m−2 over 39 to 43 days. Rates of CO2 loss measured during non-drought conditions were generally higher than those previously reported from studies in Europe and North America, presumably because of generally high soil temperatures, non-limiting moisture conditions and high organic carbon availability at our study site. The ‘net impact of cultivation’ (taking into account both direct respiratory losses of CO2 and the lack of photosynthetic carbon input following cultivation) across the three experiments ranged between 77 and 406 g C m−2 over 39–43 days. Both direct CO2 respiratory losses and the net impact of cultivation appeared highly dependent on soil moisture status, with lowest losses measured during a severe drought and highest losses measured in spring when ample moisture was present. Rates of respiratory CO2 losses did not decrease over the duration of our experiments (39–43 days). Our results suggest that when aiming to reduce C losses resulting from cultivation of permanent grassland, it is preferable to cultivate when conditions for soil microbial activity and photosynthesis are sub-optimal; for our study site this meant in autumn instead of spring because of lower soil moisture availability. We also recommend minimising the duration of the period between spraying the old sward and establishment of the new sward or crop.

In the developing world major public health issues such as malnutrition and compromised physical development are intimately linked to altered gut morphology and function with underlying chronic inflammatory responses. In these societies the downward spiral of malnutrition and infections does not seem to be remedied by well-informed nutritional interventions that supplement the identified nutrient deficiencies, suggesting that additional strategies are needed. The aim of this scientific opinion paper is to consider how a child from the developing world might benefit, separately and additively, from interventions targeted to impact hygiene, nutritional status, disease resistance and gut function, if successful interventions could be found. A failure to tackle environmental enteropathy (EE) may be a critical limiting factor that can explain the relative lack of success of interventions focussed on micronutrient supplementation so far. Therefore this paper starts with a summary of the aetiology and consequences of EE on child health and the current recommendations aimed at tackling this problem. Then a number of hypotheses will be considered in terms of research strategy to positively affect nutritional status, intestinal health and growth of children with EE, with the aim of inspiring future innovative strategies, for both the food industry and the public health sector, which could benefit millions of children.

Aim The Bravo wireless pH monitoring system enables oesophageal pH to be monitored in children intolerant to nasal catheters and records measurements over 48 hours. This study aimed to document the minimum child weight that enabled successful capsule placement and any associated complications. We also compared the diagnostic sensitivity of 48 hours versus 24 hours. Methods We included 203 consecutive patients (122 male children) with clinically documented or suspected reflux symptoms. The age range was two years to 19 years, and the minimum weight was 9.29 kg. The pH capsule was deployed endoscopically under general anaesthetic. Recordings taken over 24 and 48 hours were compared to determine the frequency of differences and correlations in the reflux index and DeMeester scores. Results Testing using the detached probe was successful in 190 children (93.6%) with weight as low as 9.29 kg, with no side effects, with failed deployment being the most frequent problem. Clinically different results in the reflux index were found in 16% of the children's day 1 or day 2 readings (p < 0.0001), suggesting the benefit of 48-hour measurements. Conclusion Measuring oesophageal pH with the Bravo wireless pH monitoring system was successful in 93.6% of cases. A 48-hour test improved the detection rate of gastro-oesophageal reflux disease by 16%.

Background. Helicobacter pylori, one of the commonest chronic bacterial infections of humankind, is an important risk factor for gastric carcinoma. It has also been suggested to be present in dental plaque. This study investigated the potential link between the number of teeth lost and H. pylori seropositivity at age 50 years. Methods. H. pylori seropositivity at age 50 years was investigated among 334 individuals born in Newcastle upon Tyne, United Kingdom, in May and June 1947 and related to the number of teeth lost, after adjusting for socioeconomic status. Results. The unadjusted risk of being seropositive for H. pylori increased with increasing number of teeth lost (odds ratio per tooth 1.03, 95% confidence interval 1.01–1.06, p = .019). However, after adjustment for socioeconomic status at birth and at age 50 years, the relationship was no longer significant (p = .36). Conclusions. Our results, obtained using prospectively collected data, suggest that any relationship between poor oral health and seropositivity to H. pylori may be due to both tooth loss and H. pylori colonization being associated with socioeconomic status and related factors.

Investigate whether fecal neopterin concentration (a potential marker of gut inflammation) in Gambian children with enteropathy was associated with growth failure. Secondary outcome measures tested the associations between Giardia lamblia infestation, fecal neopterin and lactulose mannitol absorption ratio(L:M), a measure of intestinal permeability.Seventy-two children had height and weight measured every 6 to 8 weeks until 15 months of age in a rural Gambian village. L:M ratio, a measure of small intestinal permeability and fecal neopterin were measured at these times. Stool was examined by immunofluorescence and light microscope for Giardia cysts.Long-term height and weight gains were negatively associated with mean subject fecal neopterin concentration (r = -0.29 and -0.36, respectively; P0.001). There was no correlation between fecal neopterin and intestinal permeability or history of diarrhea. Of 72 children studied, 19 had Giardia cysts in stool and 38 had negative stool examinations. Infected children had a mean of 0.7 days of diarrhea/week (95% confidence interval [CI], 0.31-1.03) versus 0.8 days/week (95% CI, 0.71-0.85) in uninfected children. No difference in growth was detected between those with positive or negative fecal smears. Mean L:M ratio was the same in both groups (0.31; 95% CI, 0.26-0.34).Consistent with the theory that intestinal inflammation in tropical infants may impair growth, fecal neopterin concentrations were inversely associated with growth. Factors other than Giardia are causing enteropathy and growth failure in Gambian infants.

Background Helicobacter pylori infection is acquired in early childhood and persists for life (or until eradication treatment is taken). Seropositivity of H. pylori at age 49-51 years was assessed in relation to socio-economic deprivation in early life and the timing of other childhood infections common at that time. Methods Prospectively collected socio-economic and morbidity data from the Newcastle Thousand Families study, a birth cohort established in 1947. H. pylori IgG seropositivity was assessed at 49-51 years and examined in relation to both whether the individual had been diagnosed with one of measles, mumps or chicken pox, and, if so, the age at first infection. This was done in logistic regression models, allowing adjustment for socio-economic status and housing quality in childhood. Results Adult H. pylori status was strongly linked to disadvantaged socio-economic status in early life (p ≤ 0.002), unlike measles, mumps and chicken pox which showed no associations. Early measles infection was independently associated with H. pylori seropositivity (p = 0.01). Conclusions Of the four infectious diseases that we have studied, it appears that H. pylori differs from the others by the strength of association with socio economic deprivation in early childhood. Our findings further highlight the complex interaction between measles, childhood infections and other non-microbiological factors that occur within a whole population. These data suggest a strong association between H. pylori and deprivation and raise the possibility of an interaction between early measles exposure and increased risk of exposure to H. pylori infection.

Consider infants and young pre-school children as different from older children. The vomiting child is very obvious, but the consequences of reflux esophagitis can be marked with a lesser grade of reflux (GORD without vomiting) (Tables 23.1 and 23.2).

Background. Duodenal ulcer in adults chronically infected with Helicobacter pylori is associated with a polarized T-helper cell type 1 (Th1) mucosal immune response, with a predominantly immunoglobulin G2 (IgG2) systemic specific response. It has been suggested that children colonized by H. pylori also produce a mucosal Th1 response, but there are few studies that have measured IgG subclass responses in children with duodenal ulcer. Materials and methods. Seven children with endoscopically proven duodenal ulcer and H. pylori infection and 18 children with biopsy proven H. pylori infection but no duodenal ulcer had relative concentrations of IgG subclass responses (IgGsc) against H. pylori antigens measured by ELISA. Eighteen IgG seropositive adults acted as controls. The range of antigens recognised by IgG1 and IgG2 subclass responses were investigated by Western blots. Results. There were no differences in mean IgGsc responses between children with or without duodenal ulcer. Adults produced an IgG2 predominant response. Western blots showed no qualitative differences in antigens recognised by IgG1 or IgG2. Conclusion. Children with duodenal ulcer, in contrast to adults, produce an IgGsc response consistent with a mucosal Th2 response to H. pylori regardless of the presence of duodenal ulceration. This suggests that disease causation amongst children with H. pylori associated duodenal ulceration may not be dependant upon a mucosal Th1 biased response.

Helicobacter pylori infects one-half of the world's population, leading to peptic ulcer in up to 15% of adult cases, and increases the risk of gastric adenocarcinoma by 2.3- to 9-fold ([11][1]). Colonization induces an intense immune response in the human host which rarely leads to clearance of the

Previous studies from The Gambia have shown that poor childhood growth is resistant to all but the most intense nutritional intervention and highly dependent on small bowel permeability related to enteropathy. We thus aimed to characterize the mucosal inflammatory response in rural Gambian children in relation to intestinal permeability and nutritional status. Small bowel biopsies were taken from 38 rural Gambian children (age, 0.5-3 y) with a range of nutritional and clinical states (median weight z score, -4.6; range, 0.5 to -6.4), 75% of whom had diarrhea. Morphometry was performed with immunohistochemical analysis for a range of lineage and activation markers, including proinflammatory and regulatory cytokines, and related to current clinical status and gut permeability. Comparison was made with 19 age-matched U.K. controls. All Gambian children, regardless of nutritional status, had evidence of chronic cell-mediated enteropathy with crypt hyperplasia, villous stunting, and high numbers of intraepithelial lymphocytes. CD25+ cells were 20-fold higher than in U.K. controls. Although small bowel architecture was independent of nutritional status, T cell numbers rose and B cell numbers fell with worsening nutrition, and mucosal cytokine production became biased toward a proinflammatory response, with progressive decrease of transforming growth factor-beta expression. Tropical enteropathy predates the onset of marasmus and is characterized by a cell-mediated TH1 response. Protein-energy malnutrition is associated with reduction of regulatory immune responses in the mucosal microenvironment, potentially impairing the mechanisms of oral tolerance.

Small bowel enteropathy (assessed by the lactulose (L): mannitol (M) permeability test) is a major factor in infant growth faltering and malnutrition in The Gambia. However, little is known about its persistence and nutritional effect beyond 2 years of age. This was addressed by two cross-sectional studies of intestinal permeability and nutritional status in 162 residents, aged 2–60 years, living in three villages in rural Gambia. L:M ratio was found to be highest in the youngest children and although there was a significant improvement with age (PPPP=0·018). The close within-subject correlation of permeability variabilities between the two visits suggests a long-term persistence of enteropathy within individuals. It appears that the small bowel enteropathy previously described in Gambian infants persists through to adulthood. Although the lesion improves with age, the relationship between attained height and L:M permeability raises the possibility that enteropathy may continue to limit growth throughout childhood and puberty.

ABSTRA C T Background. Helicobacter pylori infection is very common in Africa, yet peptic ulcer disease and gastric malignancy are rare. Aim. The aim of this study was to quantify mucosal responses to H. pylori in Gambian adults and children and to estimate the prevalence of antibodies to bacterial virulence factors ( cagA and vacA ) in a symptomatic population. Patients and methods. Adults (mean 36 SD 12 years) with dyspepsia and children (mean 1.4 years SD 0.4 years) with malnutrition underwent gastroscopy with biopsy. Blood was simultaneously drawn for cagA and vacA antibody status. Histopathological scoring used the modified Sydney classification. Results. Both adults (n = 45) and children (n = 37) mainly demonstrated chronic mild antral inflammation. Only 2/83 cases of focal atrophy (GA) and 4/83 cases of intestinal metaplasia (IM) were observed. Adults tended to demonstrate more frequent acute (AI) and chronic inflammation (CI) (38% compared with 18% and 85% compared with 72%, respectively). Sixty-seven percent of children were cagA IgG+ and 21% vacA IgG+ and 93% of adults were IgG cagA + and 86% vacA +. There were no differences in mucosal responses between those who were cagA or vacA positive compared with those who were negative. Conclusion. Gambian adults and children mount a CI response to H. pylori but GA, IM and AI are uncommon. cagA and vacA are commonly expressed in Gambian strains of H. pylori. Further studies are needed in order to confirm that GA and IM are not late findings in old age.

Azathioprine leads to changes in mean corpuscular volume (MCV) and white blood cell (WBC) indices reflecting efficacy or toxicity. Understanding the interactions between bone marrow stem cells and azathioprine could highlight abnormal response patterns as forerunners for hematologic malignancies. This study gives a statistical description of factors influencing the relationship between MCV and WBC in children with inflammatory bowel disease treated with azathioprine. We found that leukopenia preceded macrocytosis. Macrocytosis is therefore not a good predictor of leukopenia. Further studies will be necessary to determine the subgroup of patients at increased risk of malignancies based on bone marrow response. © 2010 Soman et al., publisher and licensee Adis Data Information BV.