The method of residual‑based bootstrap averaging of the forecast ensemble

This paper presents an optimization approach—residual-based bootstrap averaging(RBBA)—for different types of forecast ensembles.Unlike traditional residual-mean-square-error-based ensemble forecast averaging approaches,the RBBA method attempts to find optimal forecast weights in an ensemble and allows for their combi-nation into the most effective additive forecast.In the RBBA method,all the different types of forecasts obtain the optimal weights for ensemble residuals that are statisti-cally optimal in terms of the fitness function of the residuals.Empirical studies have been conducted to demonstrate why and how the RBBA method works.The experi-mental results based on the real-world time series of contemporary stock exchanges show that the RBBA method can produce ensemble forecasts with good generalization ability.

Enduring association between irritable bowel syndrome and war trauma during the Nicaragua civil war period:A population-based study

BACKGROUND Psychosocial and physical trauma are known risk factors for irritable bowel syndrome(IBS),including in war veterans,whereas war exposure in civilians is unclear.Nicaragua experienced two wars,1970-1990:The Sandinistas Revolution(1970s)and The Contra War(1980s).Our aim was to investigate the role of exposure to war trauma in the subsequent development of IBS in the context of an established health surveillance system(11000 households).AIM To investigate in a civilian population the relationship between exposure to war trauma and events and the subsequent development of IBS in the context of an established public health and demographic surveillance system in western Nicaragua.METHODS We conducted a nested population-based,cross-sectional study focused on functional gastrointestinal disorders based on Rome II criteria.1617 adults were randomly selected.The Spanish Rome II Modular Questionnaire and Harvard Trauma Questionnaire were validated in Nicaragua.War exposure was assessed with 10 measures of direct and indirect war trauma and post-war effects.Multiple exposures were defined by≥3 measures.RESULTS The prevalence of IBS was 15.2%[Female(F)17.1%,Male(M)12.0%],war exposure 19.3%(F 9.3%,M 36.7%),and post-traumatic stress disorder(PTSD)5.6%(F 6.4%,M 4.3%).Significant associations with IBS in the civilian population were observed(adjusted by gender,age,socioeconomic status,education):physical and psychological abuse[adjusted odds ratio(aOR):2.25;95%confidence interval:1.1-4.5],witnessed execution(aOR:2.4;1.1-5.2),family member death(aOR:2.2;1.2-4.2),and multiple exposures(aOR:2.7;1.4-5.1).PTSD was independently associated with IBS(aOR:2.6;1.2-5.7).CONCLUSION An enduring association was observed in the Nicaragua civilian population between specific civil war-related events and subsequent IBS.Civilian populations in regions with extended armed conflict may warrant provider education and targeted interventions for patients.

Effectiveness and safety of traditional Chinese herbs in children with cough variant asthma: a systematic review and Meta-analysis

OBJECTIVE:To systematically investigate the clinical effectiveness and safety of traditional Chinese herbs(TCHs)as an alternative to conventional medicine(CM)in children with cough variant asthma(CVA).METHODS:Randomized controlled trial(RCT)studies that were published from their inceptions to March 31,2020,were identified from the electronic databases of China National Knowledge Infrastructure,Wangfang,Pub Med,and Cochrane Central Library.The primary outcome of the review was the total effective rate(TER),and the secondary outcomes were immunoglobulin E(Ig E),peak expiratory flow(PEF),adverse drug reactions,and relapse rates of interventions.RESULTS:For the Meta-analysis,13 studies involving 992 children with CVA were included.In terms of TER and Ig E,the experimental interventions of TCH,when compared with the control interventions of CM,on pediatric CVA were found to be significantly effective(P<0.0001),whereas for spirometry,PEF was not significantly improved in the TCH group(P=0.48).The incident rates of adverse drug reaction and relapse were found to be significantly lower in the TCH group than those in the CM group(P=0.02 and P<0.0001,respectively).CONCLUSION:Compared with CM therapy,the effects of TCH therapy on pediatric CVA were significantly beneficial in terms of TER and Ig E,but not for PEF,and the methodological quality of included studies was poor.Therefore,the results should be interpreted with caution.More randomized controlled trials with rigorous experimental methodologies are required for objectivity in the future.

Metagenomics reveals the microbial community and functional metabolism variation in the partial nitritation-anammox process:From collapse to recovery

Mainstream partial nitritation-anammox(PNA)process easily suffers from performance instability and even reactor collapse in application.Thus,it is of great significance to unveil the characteristic of performance recovery,understand the intrinsic mechanism and then propose operational strategy.In this study,we combined long-term reactor operation,batch tests,and metagenomics to reveal the succession of microbial community and functional metabolism variation from system collapse to recovery.Proper aeration control(0.10-0.25mg O_(2)/L)was critical for performance recovery.It was also found that Candidatus Brocadia became the dominant flora and its abundance increased from 3.5%to 11.0%.Significant enhancements in carbon metabolism and phospholipid biosynthesis were observed during system recovery,and the genes abundance related to signal transduction was dramatically increased.The up-regulation of sdh and suc genes showed the processes of succinate dehydrogenation and succinyl-CoA synthesis might stimulate the production of amino acids and the synthesis of proteins,thereby possibly improving the activity and abundance of AnAOB,which was conducive to the performance recovery.Moreover,the increase in abundance of hzs and hdh genes suggested the enhancement of the anammox process.Changes in the abundance of key genes involved in nitrogen metabolism indicated that nitrogen removal pathway was more diverse after system recovery.The achievement of performance recovery was driven by anammox,nitrification and denitrification coupled with dissimilatory nitrate reduction to ammonium.These results provide deeper insights into the recovery mechanism of PNA system and also provide a potential regulation strategy for the stable operation of the mainstream PNA process.

In silico assessment of household level closed water cycles:Towards extreme decentralization

Water management in most of the developed world is currently practiced in a highly centralized manner,leading to major infrastructure and energy costs to transport water.To decrease the impacts of water scarcity and climate change,the decentralization of water can increase local robustness.In extremis,decentralization can involve building or house level water supply and treatment.Here,we constructed a MATLAB/Simulink model for two decentralized water management configurations at the household level,assuming the socio-environmental setting of Flanders,Belgium.Independence from the potable water grid and sewer system was pursued through rainwater harvesting,reuse of wastewater streams fitfor-purpose,and discharge via infiltration.The mass balance for water was calculated over the system boundaries showing high potential for independence from the grid with a reasonable treatment train and storage options.Next,the risk of contaminant accumulation within the circular system was assessed,showing a key limitation on decentralized system performance necessitating a system purge.Up to 59%of system rainwater usage was due to the replacement of this purge.Employing treatment units with high(95%)contaminant rejection efficiencies eliminated contaminant accumulation issues.The raw model output was quantitatively assessed by constructing four newly proposed key performance indicators(KPIs),quantifying system independence,circularity,drought tolerance and local water body recharge,which allowed for facilitated system comparison and communication to stakeholders.A sensitivity analysis was performed in which the effect of input parameter variability and uncertainty on system performance was quantified.The sensitivity analysis showed the importance of water recovery and contaminant removal efficiencies of the applied treatment technologies on system performance when contaminant accumulation in the system forms an issue.In systems not severely affected by pollutant accumulation,parameters such as inhabitant number and roof surface had the largest effect.As a whole,this work shows the potential of extreme decentralization of water systems and addresses the obstacle towards implementation formed by the accumulation of contaminants due to system circularity.Additionally,this study provides a framework for operational and technological decision support of decentralized household-scale water systems and,by extension,for future water policy-making.