26 research outputs found
Arsenic and Selenium Capture by Fly Ashes at Low Temperature
Arsenic and selenium compounds may be emitted to the environment during coal conversion processes, although some compounds are retained in the fly ashes, in different proportions depending on the characteristics of the ashes and process conditions. The possibility of optimizing the conditions to achieve better trace element retention appears to be an attractive, economical option for reducing toxic emissions. This approach requires a good knowledge of fly ash characteristics and a thorough understanding of the capture mechanism involved in the retention. In this work the ability of two fly ashes, one produced in pulverized coal combustion and the other in fluidized bed combustion, to retain arsenic and selenium compounds from the gas phase in coal combustion and coal gasification atmospheres was investigated. To explore the possible simultaneous retention of mercury, the influence of the unburned coal particle content was also evaluated. Retention capacities between 2 and 22 mg g-1 were obtained under different conditions. The unburned coal particle content in the fly ash samples does not significantly modify retention capacities.The results of this work were obtained as part of the project PPQ2001-2359-C02-02
dealing on mercury capture.Peer reviewe
Enrichment of thallium in fly ashes in a Spanish circulating fluidized-bed combustion plant
This work evaluates the behavior of thallium in a 50 MW industrial circulating fluidized-bed combustion plant (CFBC), focusing on the distribution of this element among the bottom and fly ashes separated by the solid retention devices in the plant. The results show that thallium species are mainly retained in the solid by-products and are not emitted to air with flue gases in significant amounts, proving that this technology is a more effective means of preventing thallium emissions than pulverized coal combustion technology (PCC). The mass balance of the thallium content in the solids shows that this element was retained in the ashes separated by the different devices installed in the plant. An evaluation of the ash fractions taken from the strippers, the heat recovery area, the hoppers in the air heater and the electrostatic precipitator, shows that thallium was relatively homogeneously distributed in all the ash samples, independently of their composition, but is slightly related to surface area, which in turn is dependent on particle size and unburned carbon content.The authors acknowledge the collaboration of HUNOSA (Hulleras del Norte S.A.) and the staff of La Pereda Power Plant for their assistance in taking the samples.Peer reviewe
Pergumulan as the starter and sustainer of Servant Leadership A case of academic leadership in a private University in Indonesia
In the disruptive era, every organization is expected to cope with change. This includes the ones in the sector of higher education. Servant leadership is considered as the leadership approach that enables Higher Educational Institutions (HEIs) to deal with the inevitable changes. This research explores an academic leadership in a private university in Indonesia, which endorses servant leadership as its leadership approach. The case study involves the interview of twenty-six academic leaders who have asked to answer two fundamental questions: 1) How do they perceive the invitation to lead as an academic leader and 2) What did they do as they consider whether to take the offer to lead as an academic leader? The gathered data was processed using the Qualitative Data Analysis consisting data condensation, data display and drawing and verifying conclusion. Twenty-five academic leaders said no when they first offer and this initial refusal drives the researcher to find a term called �pergumulan� as the common theme across the interviewees. �Pergumulan� or a spiritual struggle happened during the pre-leadership journey and during the leadership journey of these academic leaders. The former suggests that �pergumulan� is spiritual, intrapersonal and interpersonal. The latter indicates that pergumulan happens when the servant leaders search their motivation and figure out the way to improve themselves while serving their followers. Lastly, during their leadership, the servant leaders are also having the �pergumulan� as they have to confront or rebuke their followers
The implications of three major new trials for the effect of water, sanitation and hygiene on childhood diarrhea and stunting: a consensus statement
BACKGROUND: Three large new trials of unprecedented scale and cost, which included novel factorial designs, have found no effect of basic water, sanitation and hygiene (WASH) interventions on childhood stunting, and only mixed effects on childhood diarrhea. Arriving at the inception of the United Nations' Sustainable Development Goals, and the bold new target of safely managed water, sanitation and hygiene for all by 2030, these results warrant the attention of researchers, policy-makers and practitioners. MAIN BODY: Here we report the conclusions of an expert meeting convened by the World Health Organization and the Bill and Melinda Gates Foundation to discuss these findings, and present five key consensus messages as a basis for wider discussion and debate in the WASH and nutrition sectors. We judge these trials to have high internal validity, constituting good evidence that these specific interventions had no effect on childhood linear growth, and mixed effects on childhood diarrhea. These results suggest that, in settings such as these, more comprehensive or ambitious WASH interventions may be needed to achieve a major impact on child health. CONCLUSION: These results are important because such basic interventions are often deployed in low-income rural settings with the expectation of improving child health, although this is rarely the sole justification. Our view is that these three new trials do not show that WASH in general cannot influence child linear growth, but they do demonstrate that these specific interventions had no influence in settings where stunting remains an important public health challenge. We support a call for transformative WASH, in so much as it encapsulates the guiding principle that - in any context - a comprehensive package of WASH interventions is needed that is tailored to address the local exposure landscape and enteric disease burden
Could a brief assessment of negative emotions and self-esteem identify adolescents at current and future risk of self-harm in the community? A prospective cohort analysis
Background: Self-harm is common in adolescents, but it is often unreported and undetected. Available screening
tools typically ask directly about self-harm and suicidal ideation. Although in an ideal world, direct enquiry and
open discussion around self-harm would be advocated, non-psychiatric professionals in community settings are
often reluctant to ask about this directly and disclosure can be met with feeling of intense anxiety. Training
non-specialist staff to directly ask about self-harm has limited effects suggesting that alternative approaches are
required. This study investigated whether a targeted analysis of negative emotions and self-esteem could identify
young adolescents at risk of self-harm in community settings.
Methods: Data were collected as part of a clinical trial from young people in school years 8–11 (aged 12–16) at
eight UK secondary schools (N = 4503 at baseline, N = 3263 in prospective analysis). The Short Mood and Feelings
Questionnaire, Revised Child Anxiety and Depression Scale, Rosenberg Self-Esteem Scale, personal failure (Children’s
Automatic Thoughts Scale), and two items on self-harm were completed at baseline, 6 and 12 months.
Results: Following a process of Principal Components Analysis, item reduction, and logistic regression analysis,
three internally reliable factors were identified from the original measures that were independently associated with
current and future self-harm; personal failure (3 items), physical symptoms of depression/anxiety (6 items), positive
self-esteem (5 items). The summed score of these 14 items had good accuracy in identifying current self-harm
(AUC 0.87 girls, 0.81 boys) and at six months for girls (0.81), and fair accuracy at six months for boys (AUC 0.74) and
12 months for girls (AUC 0.77).
Conclusions: A brief and targeted assessment of negative emotions and self-esteem, focusing on factors that are
strongly associated with current and future self-harm, could potentially be used to help identify adolescents who
are at risk in community settings. Further research should assess the psychometric properties of the items identified
and test this approach in more diverse community contexts
Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study
Introduction:
The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures.
Methods:
In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025.
Findings:
Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2–6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5–5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4–10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32–4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23–11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation.
Interpretation:
After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification
Synthesis, implications, and recommendations
We set out in this book to present a comprehensive assessment of internal phosphorus (P) loading in lakes, drawing on peer reviewed literature, as well as data and expertise from case studies. Most importantly, our co-authors have imparted hundreds (collectively) of years of expertise in measurement, modelling, and management of internal loading in lakes, producing a comprehensive evidence base with which to inform future practitioners in this field. This expertise spans 16 countries from all continents (with the exception of Antarctica). The introductory chapters provide a blueprint for the study of internal loading in lakes.
Our case studies offer impressive data from some of the world’s longest limnological long-term monitoring programmes. Analysis and interpretation of these data are presented to quantify the causes of long-term variation in internal loading in 18 lakes, spanning 16 countries, including three transboundary lakes. Cumulatively, these lakes represent 64,678 km2 lake surface area draining more than 256,673 km2 of catchment surface area (Table 24.1). These case studies offer detailed process understanding with which to examine the responses of internal loading to different elements of environmental change. For example, authors highlight the importance of large scale social change as drivers of legacy P and internal loading in lakes, as well as how agricultural intensification and urbanisation following the Second World War started the accumulation of legacy P in many lake bed sediments, which, today, drives internal loading
Thallium in coal: Analysis and environmental implications
The ecotoxicological importance of thallium stems from its acute toxicity, the effects of which are as harmful to living organisms as those of lead and mercury. The main anthropogenic sources of thallium are the emissions from coal combustion processes, underlining the need to control this element in coal and coal by-products. Despite the threat posed by thallium, very little information has been published on its behaviour in coal-fired power plants or on its modes of occurrence in coal, its mobilisation and its distribution. Although thallium is highly toxic, the environmental risk presented by this element in coal utilisation have been studied to a much lesser degree than in the case of other toxic elements such as lead, cadmium or mercury. The present work addresses the issue of thallium in coal, focussing on its origin, modes of occurrence, the analytical methods commonly used for its determination and its behaviour during coal utilisation for energy production.The authors want to acknowledge the CSIC for providing M. Antonia López-Antón with a postdoctoral position.Peer reviewe