CH4 and N2 O emissions from smallholder agricultural systems on tropical peatlands in Southeast Asia.

There are limited data for greenhouse gas (GHG) emissions from smallholder agricultural systems in tropical peatlands, with data for non-CO2 emissions from human-influenced tropical peatlands particularly scarce. The aim of this study was to quantify soil CH4 and N2 O fluxes from smallholder agricultural systems on tropical peatlands in Southeast Asia and assess their environmental controls. The study was carried out in four regions in Malaysia and Indonesia. CH4 and N2 O fluxes and environmental parameters were measured in cropland, oil palm plantation, tree plantation and forest. Annual CH4 emissions (in kg CH4 ha-1 year-1 ) were: 70.7 ± 29.5, 2.1 ± 1.2, 2.1 ± 0.6 and 6.2 ± 1.9 at the forest, tree plantation, oil palm and cropland land-use classes, respectively. Annual N2 O emissions (in kg N2 O ha-1 year-1 ) were: 6.5 ± 2.8, 3.2 ± 1.2, 21.9 ± 11.4 and 33.6 ± 7.3 in the same order as above, respectively. Annual CH4 emissions were strongly determined by water table depth (WTD) and increased exponentially when annual WTD was above -25 cm. In contrast, annual N2 O emissions were strongly correlated with mean total dissolved nitrogen (TDN) in soil water, following a sigmoidal relationship, up to an apparent threshold of 10 mg N L-1 beyond which TDN seemingly ceased to be limiting for N2 O production. The new emissions data for CH4 and N2 O presented here should help to develop more robust country level 'emission factors' for the quantification of national GHG inventory reporting. The impact of TDN on N2 O emissions suggests that soil nutrient status strongly impacts emissions, and therefore, policies which reduce N-fertilisation inputs might contribute to emissions mitigation from agricultural peat landscapes. However, the most important policy intervention for reducing emissions is one that reduces the conversion of peat swamp forest to agriculture on peatlands in the first place.

Microplastic concentrations in river water and bed sediments in a tropical river: implications for water quality monitoring.

Recent increase in awareness of the extent of microplastic contamination in marine and freshwater systems has heightened concerns over the ecological and human health risks of this ubiquitous material. Assessing risks posed by microplastic in freshwater systems requires sampling to establish contamination levels, but standard sampling protocols have yet to be established. An important question is whether sampling and assessment should focus on microplastic concentrations in the water or the amount deposited on the bed. On three dates, five replicated water and bed sediment samples were collected from each of the eight sites along the upper reach of the Semenyih River, Malaysia. Microplastics were found in all 160 samples, with mean concentrations of 3.12 ± 2.49 particles/L in river water and 6027.39 ± 16,585.87 particles/m2 deposited on the surface of riverbed sediments. Fibres were the dominant type of microplastic in all samples, but fragments made up a greater proportion of the material on the bed than in the water. Within-site variability in microplastic abundance was high for both water and bed sediments, and very often greater than between-site variability. Patterns suggest that microplastic accumulation on the bed is spatially variable, and single samples are therefore inadequate for assessing bed contamination levels at a site. Sites with the highest mean concentrations in samples of water were not those with the highest concentrations on the bed, indicating that monitoring based only on water samples may not provide a good picture of either relative or absolute bed contamination levels, nor the risks posed to benthic organisms.

Relative contributions of different local sources to riverborne microplastic in a mixed landuse area within a tropical catchment.

Information on the relative contributions of microplastics coming from different sources is important to help prioritise measures to reduce river contamination levels and limit human and ecological health risks. This paper reports on work which aimed to quantitatively assess the relative concentrations and types of microplastic delivered from differed sources to a second order river. The study was undertaken in a mixed landuse area within a rapidly urbanising catchment in Malaysia. Over a six-week period, water samples were collected from road culverts and drains in residential and industrial areas across the area to assess microplastic concentrations, while inputs from atmospheric deposition and wastewater treatment plants (WWTPs) were also quantified. Microplastic fibres and fragments were the dominant material in all sources, with the majority consisting of styrene-butadiene rubber and nylon. Culverts draining main roads were the main contributor to riverborne microplastic, delivering 42.20 ± 35.29 particles/L directly to the river channel. Road inputs were up to seven times greater than those from residential (8.53 ± 9.91 particles/L) and industrial (5.67 ± 4.88 particles/L) areas. The five WWTPs had removal efficiencies of between 30.95 ± 5.51% and 69.94 ± 22.17%, with their outflows delivering microplastics to the river in concentrations similar to those in uncontrolled residential and industrial drains. Atmospheric deposition across the study area was estimated to be 76.07 ± 32.85 particles/m2/day (=8.35 ± 5.11 particles/L). Mitigation strategies in the study area should focus on improving management of water draining roads, and re-routing discharges from domestic and industrial areas to WWTPs rather than allowing them to flow directly to the river. The low efficiencies of some of the WWTPs are not unusual, and indicate the need for additional water treatment to deal with microplastic present in wastewater.

Spatio-temporal variation of microplastic along a rural to urban transition in a tropical river.

Microplastic pollution is widely recognised as a global issue, posing risks to natural ecosystems and human health. The combination of rapid industrial and urban development and relatively limited environmental regulation in many tropical countries may increase the amount of microplastic entering rivers, but basic data on contamination levels are lacking. This is especially the case in tropical South East Asian countries. In this paper, the abundance, composition and spatio-temporal variation of microplastic in the Langat River, Malaysia, were assessed, and the relationship between microplastic concentration and river discharge was investigated. Water samples were collected over a 12-month period from 8 sampling sites on the Langat, extending from forested to heavily urbanised and industrial areas. All 508 water samples collected over this period contained microplastic; mean concentration across all sites and times was 4.39 particles/L but extended up to 90.00 particles/L in some urban tributaries. Most microplastics were secondary in origin, and dominated by fibres. Microplastic counts correlated directly with river discharge, and counts increased and decreased in response to changes in flow. A time-integrated assessment of the microplastic load conveyed by the Langat suggested that the river is typically (50 % of the time) delivering around 5 billion particles per day to the ocean. The positive correlation between the concentration of microplastics and suspended sediments in the Langat suggested that continuously logging turbidity sensors could be used to provide better estimates of microplastic loads and improve assessment of human and ecological health risks.

Microplastic pollution in freshwater systems in Southeast Asia: contamination levels, sources, and ecological impacts.

Plastics are synthetic polymers known for their outstanding durability and versatility, and have replaced traditional materials in many applications. Unfortunately, their unique traits ensure that they pose a major threat to the environment. While literature on freshwater microplastic contamination has grown over the recent years, research undertaken in rapidly developing countries, where plastic production and use are increasing dramatically, has lagged behind that in other parts of the world. In the South East Asia (SEA) region, basic information on levels of contamination is very limited and, as a consequence, the risk to human and ecological health remains hard to assess. This review synthesises what is currently known about microplastic contamination of freshwater ecosystems in SEA, with a particular focus on Malaysia. The review 1) summarises published studies that have assessed levels of contamination in freshwater systems in SEA, 2) discusses key sources and transport pathways of microplastic in freshwaters, 3) outlines what is known of the impacts of microplastic on freshwater organisms, and 4) identifies key knowledge gaps related to our understanding of the transport, fate and effects of microplastic.

A review of the impacts of dams on the hydromorphology of tropical rivers.

A major programme of dam building is underway in many of the world's tropical countries. This raises the question of whether existing research is sufficient to fully understand the impacts of dams on tropical river systems. This paper provides a systematic review of what is known about the impacts of dams on river flows, sediment dynamics and geomorphic processes in tropical rivers. The review was conducted using the SCOPUS® and Web of Science® databases, with papers analysed to look for temporal and geographic patterns in published work, assess the approaches used to help understand dam impacts, and assess the nature and magnitude of impacts on the flow regimes and geomorphology ('hydromorphology') of tropical rivers. As part of the review, a meta-analysis was used to compare key impacts across different climate regions. Although research on tropical rivers remains scarce, existing work is sufficient to allow us to draw some very broad, general conclusions about the nature of hydromorphic change: tropical dams have resulted in reductions in flow variability, lower flood peaks, reductions in sediment supply and loads, and complex geomorphic adjustments that include both channel incision and aggradation at different times and downstream distances. At this general level, impacts are consistent with those observed in other climate regions. However, studies are too few and variable in their focus to determine whether some of the more specific aspects of change observed in tropical rivers (e.g. time to reach a new, adjusted state, and downstream recovery distance) differ consistently from those in other regions. The review helps stress the need for research that incorporates before-after comparisons of flow and geomorphic conditions, and for the wider application of tools available now for assessing hydromorphic change. Very few studies have considered hydromorphic processes when designing flow operational policies for tropical dams.

COVID-19 Management in a UK NHS Foundation Trust with a High Consequence Infectious Diseases Centre: A Retrospective Analysis.

Recent large national and international cohorts describe the baseline characteristics and outcome of hospitalised patients with COVID-19, however there is limited granularity to these reports. We aimed to provide a detailed description of a UK COVID-19 cohort, focusing on management and outcome. We performed a retrospective single-centre analysis of clinical management and 28-day outcomes of consecutive adult inpatients with SARS-CoV-2 PCR-confirmed COVID-19 from 31 January to 16 April 2020 inclusive. In total, 316 cases were identified. Most patients were elderly (median age 75) with multiple comorbidities. One quarter were admitted from residential or nursing care. Mortality was 84 out of 316 (26.6%). Most deaths occurred in patients in whom a ceiling of inpatient treatment had been determined and for whom end of life care and specialist palliative care input was provided where appropriate. No deaths occurred in patients aged under 56 years. Decisions to initiate respiratory support were individualised after consideration of patient wishes, premorbid frailty and comorbidities. In total, 59 (18%) patients were admitted to intensive care, of which 31 (10% overall cohort) required intubation. Multiple logistic regression identified associations between death and age, frailty, and disease severity, with age as the most significant factor (odds ratio 1.07 [95% CI 1.03-1.10] per year increase, p < 0.001). These findings provide important clinical context to outcome data. Mortality was associated with increasing age. Most deaths were anticipated and occurred in patients with advance decisions on ceilings of treatment.

The Functional Impact of Sleep Disorders in Children With ADHD.

Objective: Children with ADHD display higher rates of sleep problems, and both sleep disorders and ADHD have been shown to affect functioning in childhood. The current study examines the frequency and relationship between sleep problems and ADHD, and their impact on quality of life (QoL) and functional impairment. Method: Parents of 192 children with ADHD (M = 10.23 years) completed measures regarding their child's ADHD symptoms (Swanson, Nolan and Pelham [SNAP]), sleep disorders (Pediatric Sleep Questionnaire [PSQ]), QoL (Child Health Illness Profile [CHIP-PE]), and functioning (Weiss Functional Impairment Rating Scale-Parent Report [WFIRS-P]). Results: Common sleep complaints in participants were insomnia, excessive daytime sleepiness (EDS), and variability in sleep schedule. Regression analysis indicated that sleep problems and ADHD symptoms independently predicted lower levels of QoL (ΔR2 = .12, p < .001) and social functioning (ΔR2 = .12, p < .001). Conclusion: The results suggest that ADHD may coexist with somnolence and that both conditions have a significant impact on a child's functioning and QoL.

Long term flow change threatens invertebrate diversity in temporary streams: Evidence from an island.

Here we provide the first evidence of long term reductions in flow in temporary streams on the Mediterranean island of Mallorca and use a simple metric of the degree of water permanence (the number of days with water) to highlight the implications of flow change for aquatic invertebrate diversity. Analysis of a 33year data set for 13 streams on the island yielded evidence of consistent downward trends in water permanence, particularly in spring and summer. Data from 27 relatively undisturbed mountain streams indicate that the diversity of benthic invertebrates in temporary streams across the island is directly related to water permanence. Streams with lower values of water permanence support few species overall and have less abundant invertebrate assemblages; the abundance and species richness of sensitive mayfly, stonefly and caddisfly taxonomic groups is also reduced in streams with lower water permanence. Although developed using spatial data, these flow-invertebrate relationships suggest that future reductions in water permanence may lead to reduced diversity. We argue that the 'number of days with water' is a simple but ecologically-relevant metric of water permanence that can be used effectively to monitor change in threatened temporary streams worldwide.

Evidence for a general factor model of ADHD in adults.

OBJECTIVE: To examine factor structures of Diagnostic and Statistical Manual of Mental Disorders (4th ed.) symptoms of ADHD in adults. METHOD: Two sets of models were tested: (a) models with inattention and hyperactivity/impulsivity as separate but correlated latent constructs and (b) hierarchical general factor models with a general factor for all symptoms and separate specific factors for inattention and hyperactivity/impulsivity. Participants were 751 adults with ADHD. Two models with correlated factors and two general factor models of ADHD symptoms were tested. RESULTS: The general factor model provided a better fit of the data than the correlated models. The general factor model with one general and three (inattention, motoric, and verbal hyperactivity/impulsivity) specific factors best accounted for the adults' symptoms. CONCLUSION: These results suggest a unitary component to ADHD symptoms as well as dimensional specific factors. The replication of a general factor in adults suggests continuity of symptom presentation from childhood into adulthood. Clinical implications are discussed.

Time courses of improvement and symptom remission in children treated with atomoxetine for attention-deficit/hyperactivity disorder: analysis of Canadian open-label studies.

BACKGROUND: The relatively short durations of the initial pivotal randomized placebo-controlled trials involving atomoxetine HCl for the treatment of attention-deficit/hyperactivity disorder (ADHD) provided limited insight into the time courses of ADHD core symptom responses to this nonstimulant, selective norepinephrine reuptake inhibitor. The aim of this analysis was to evaluate time courses of treatment responses or remission, as assessed by attainment of prespecified scores on the ADHD Rating Scale-IV-Parent Version: Investigator Administered and Scored (ADHDRS-IV-PI) and the Clinical Global Impressions-ADHD-Severity (CGI-ADHD-S) scales, during up to 1 year of atomoxetine treatment in children with ADHD. METHODS: Using pooled data from three Canadian open-label studies involving 338 children ages 6-11 years with ADHD who were treated with atomoxetine for 3, 6 and 12 months, and survival analysis methods for interval-censored data, we estimated the time to: 1) improvement and robust improvement defined by ≥25% and ≥40% reductions from baseline ADHDRS-IV-PI total scores, respectively; and 2) remission using two definitions: a final score of ADHDRS-IV-PI ≤18 or a final score of CGI-ADHD-S ≤2. RESULTS: The median time to improvement was 3.7 weeks (~1 month), but remission of symptoms did not occur until a median of 14.3 weeks (~3.5 months) using the most stringent CGI-ADHD-S threshold. Probabilities of robust improvement were 47% at or before 4 weeks of treatment; 76% at 12 weeks; 85% at 26 weeks; and 96% at 52 weeks. Probabilities of remission at these corresponding time points were 30%, 59%, 77%, and 85% (using the ADHDRS-IV scale) and 8%, 47%, 67%, and 75% (using the CGI-ADHD-S scale). The change from atomoxetine treatment month 5 to month 12 of -1.01 (1.03) was not statistically significant (p = .33). CONCLUSIONS: Reductions in core ADHD symptoms during atomoxetine treatment are gradual. Although approximately one-half of study participants showed improvement at 1 month of atomoxetine treatment, remission criteria were not met until about 3 months. Understanding the time course of children's responses to atomoxetine treatment may inform clinical decision making and also influence the durations of trials comparing the effects of this medication with other ADHD treatments. TRIAL REGISTRATIONS: clinicaltrials.gov: NCT00191633, NCT00216918, NCT00191880.

Time course and predictors of health-related quality of life improvement and medication satisfaction in children diagnosed with attention-deficit/hyperactivity disorder treated with the methylphenidate transdermal system.

OBJECTIVE: The aim of this study was to evaluate the time course and predictors of improvement in health-related quality of life (HRQL) and medication satisfaction in children diagnosed with attention-deficit/hyperactivity disorder (ADHD) and treated with the methylphenidate transdermal system (MTS). METHODS: Temporal relationships between ADHD symptoms, medication satisfaction, and HRQL measures were examined via latent growth curve, structural path, and growth mixture models. RESULTS: Higher levels of medication satisfaction at the end of titration predicted greater increases in family HRQL (p=0.004) and, to a lesser extent, child HRQL (p=0.068) throughout the study. At 4 of 6 (p<0.05) and 5 of 6 (p<0.10) contemporaneous time points, ADHD symptoms predicted child HRQL. At 2 of 6 (p<0.05) and 3 of 6 (p<0.10) contemporaneous time points, ADHD symptoms predicted family HRQL. ADHD did not predict child or family HRQL improvements at subsequent time points. A uniform pattern of change for child HRQL was noted, with most HRQL change following the pattern of symptom change during titration. Three distinct patterns of change were noted for family HRQL. CONCLUSIONS: In most cases, medication satisfaction, ADHD symptoms, and HRQL improved simultaneously, suggesting that HRQL was not a delayed response to improvement in symptoms. Children showed a uniform pattern of improvement in HRQL that followed symptom change; three distinct patterns of change were found for improvement in family HRQL.

ADHD-hyperactive/impulsive subtype in adults.

This is the first study to evaluate ADHD-hyperactive/impulsive subtype in a large clinical sample of adults with ADHD. The Quality of Life, Effectiveness, Safety and Tolerability (QuEST) study included 725 adults who received clinician diagnoses of any ADHD subtype. Cross-sectional baseline data from 691 patients diagnosed with the hyperactive/impulsive (HI), inattentive (IA) and combined subtypes were used to compare the groups on the clinician administered ADHD-RS, clinical features and health-related quality of life. A consistent pattern of differences was found between the ADHD-I and combined subtypes, with the combined subtype being more likely to be diagnosed in childhood, more severe symptom severity and lower HRQL. Twenty-three patients out of the total sample of 691 patients (3%) received a clinician diagnosis of ADHD-hyperactive/impulsive subtype. Review of the ratings on the ADHD-RS-IV demonstrated, however, that this group had ratings of inattention comparable to the inattentive group. There were no significant differences found between the ADHD-HI and the other subtypes in symptom severity, functioning or quality of life. The hyperactive/impulsive subtype group identified by clinicians in this study was not significantly different from the rest of the sample. By contrast, significant differences were found between the inattentive and combined types. This suggests that in adults, hyperactivity declines and inattention remains significant, making the hyperactive/impulsive subtype as defined by childhood criteria a very rare condition and raising questions as to the validity of the HI subtype in adults.

Moderators and mediators of symptoms and quality of life outcomes in an open-label study of adults treated for attention-deficit/hyperactivity disorder.

OBJECTIVE: The Quality of Life, Effectiveness, Safety, and Tolerability (QU.E.S.T.) study was designed to evaluate effectiveness of long-acting amphetamines in adults with attention-deficit/hyperactivity disorder (ADHD) in community practice settings. This article reports moderators and mediators of symptoms and quality of life outcomes. METHOD: This was an open-label study of 725 adults with DSM-IV-diagnosed ADHD, treated with mixed amphetamine salts extended release and followed for up to 8 months. Multiple regressions were used to determine if patient moderators impact response in ADHD symptoms and how ADHD symptoms and medication satisfaction mediate quality of life. The study was conducted from December 2003 to December 2004. RESULTS: Amphetamine treatment of ADHD resulted in a robust and enduring symptom response. Patient characteristics such as age, female gender, severity of illness, and treatment-naive status moderate improved symptom outcome. Symptom change and satisfaction with medication independently mediate change in mental but not physical quality of life outcomes. There is no time lag between changes in symptoms and improved quality of life. Attention is a stronger mediator of ADHD-specific quality of life outcomes than disruptive behavior. CONCLUSIONS: If symptoms and quality of life improve simultaneously, improvement in quality of life can be understood as more than just a downstream, secondary effect of symptom remission. Satisfaction with medication is a direct measure of the complex interplay of symptom change, tolerability, and patient perception of treatment that predicts self-report of quality of life benefits. Although the disruptive symptoms of ADHD are more obvious, adults self-report that attention has greater impact.

A naturalistic study of predictors and risks of atypical antipsychotic use in an attention-deficit/hyperactivity disorder clinic.

OBJECTIVE: This was an exploratory study to examine the use of atypical antipsychotics in an attention-deficit/hyperactivity disorder (ADHD) clinic. METHOD: A total of 194 patients was examined to compare those receiving atypical or second-generation antipsychotics (atypicals) from those who were not. A sample of 27 children on atypicals received laboratory investigation for indicators of possible metabolic effects. RESULTS: In all, 19.1% of the patients in the clinic were receiving atypicals with a mean duration of 313 days; 36 of 37 patients on atypicals had received risperidone, with a mean dose of 0.62 mg. Children receiving atypicals were statistically more likely to have a severe co-morbid disorder, a lower Children's Global Assessment Scale score, a greater total score on the teacher Strengths and Difficulties Questionnaire, and greater difficulty with parent-rated symptoms of being touchy, worried, rages, and explosive outbursts. There were no differences found in measures of functioning, adaptive skills, quality of life, or ADHD symptoms. In the subset of children studied for potential metabolic effects, 68.0% had a waist circumference > or =90(th) percentile that was independent of weight gain, 18.5% had impaired fasting glucose, 12.5% had elevated blood pressure, 11.1% had elevated triglycerides, and 16.7% met full criteria for metabolic syndrome. CONCLUSION: Clinical implementation of the efficacy studies of risperidone for disruptive behavior disorders has led to a significant change in practice. Almost 1 in 5 patients are now receiving atypical neuroleptics, typically to treat severe co-morbid disorders and symptoms other than ADHD per se. Despite these children receiving low doses, concomitant stimulants, and low body mass index z-scores, a significant proportion of children demonstrated either one or more components or the full criteria for metabolic syndrome.

Clinical recommendations in current practice guidelines for diagnosis and treatment of ADHD in adults.

Attention-deficit/hyperactivity disorder (ADHD) is a lifelong neurodevelopmental disorder in which approximately two thirds of patients experience impairment in adulthood. Although some adults with ADHD were diagnosed as children, many are first diagnosed as adults. This poses particular challenges given the limited familiarity with ADHD of many adult mental health services. As a result, several organizations, including the Canadian ADHD Resource Alliance, the American Academy of Child and Adolescent Psychiatry, the National Institutes of Health, and the British Association for Psychopharmacology, have developed practice guidelines for the assessment and treatment of adults with ADHD. This article reviews those guidelines in order to examine current best practices in adult ADHD. There is considerable agreement among these guidelines, which should be a critical part of moving from emerging knowledge to patient care, although both empirical evaluation and ongoing updates as new knowledge emerges will be important for their future development.