Pan-European rural monitoring network shows dominance of NH3 gas and NH4NO3 aerosol in inorganic atmospheric pollution load

A comprehensive European dataset on monthly atmospheric NH3, acid gases (HNO3, SO2, HCl), and aerosols (NH4+, NO3-, SO42-, Cl−, Na+, Ca2+, Mg2+) is presented and analysed. Speciated measurements were made with a low-volume denuder and filter pack method (DEnuder for Long-Term Atmospheric sampling, DELTA®) as part of the EU NitroEurope (NEU) integrated project. Altogether, there were 64 sites in 20 countries (2006–2010), coordinated between seven European laboratories. Bulk wet-deposition measurements were carried out at 16 co-located sites (2008–2010). Inter-comparisons of chemical analysis and DELTA® measurements allowed an assessment of comparability between laboratories. The form and concentrations of the different gas and aerosol components measured varied between individual sites and grouped sites according to country, European regions, and four main ecosystem types (crops, grassland, forests, and semi-natural). The smallest concentrations (with the exception of SO42- and Na+) were in northern Europe (Scandinavia), with broad elevations of all components across other regions. SO2 concentrations were highest in central and eastern Europe, with larger SO2 emissions, but particulate SO42- concentrations were more homogeneous between regions. Gas-phase NH3 was the most abundant single measured component at the majority of sites, with the largest variability in concentrations across the network. The largest concentrations of NH3, NH4+ and NO-3 were at cropland sites in intensively managed agricultural areas (e.g. Borgo Cioffi in Italy), and the smallest were at remote semi-natural and forest sites (e.g. Lompolojänkkä, Finland), highlighting the potential for NH3 to drive the formation of both NH4+ and NO3- aerosol. In the aerosol phase, NH4+ was highly correlated with both NO3- and SO42-, with a near-1:1 relationship between the equivalent concentrations of NH4+ and sum(NO3- + SO42-) of which around 60 % was as NH4NO3. Distinct seasonality was also observed in the data, influenced by changes in emissions, chemical interactions, and the influence of meteorology on partitioning between the main inorganic gases and aerosol species. Springtime maxima in NH3 were attributed to the main period of manure spreading, while the peak in summer and trough in winter were linked to the influence of temperature and rainfall on emissions, deposition, and gas–aerosol-phase equilibrium. Seasonality in SO2 was mainly driven by emissions (combustion), with concentrations peaking in winter, except in southern Europe, where the peak occurred in summer. Particulate SO42− showed large peaks in concentrations in summer in southern and eastern Europe, contrasting with much smaller peaks occurring in early spring in other regions. The peaks in particulate SO42- coincided with peaks in NH3 concentrations, attributed to the formation of the stable (NH4)2SO4. HNO3 concentrations were more complex, related to traffic and industrial emissions, photochemistry, and HNO3:NH4NO3 partitioning. While HNO3 concentrations were seen to peak in the summer in eastern and southern Europe (increased photochemistry), the absence of a spring peak in HNO3 in all regions may be explained by the depletion of HNO3 through reaction with surplus NH3 to form the semi-volatile aerosol NH4NO3. Cooler, wetter conditions in early spring favour the formation and persistence of NH4NO3 in the aerosol phase, consistent with the higher springtime concentrations of NH4+ and NO3−. The seasonal profile of NO3- was mirrored by NH4+, illustrating the influence of gas–aerosol partitioning of NH4NO3 in the seasonality of these components. Gas-phase NH3 and aerosol NH4NO3 were the dominant species in the total inorganic gas and aerosol species measured in the NEU network. With the current and projected trends in SO2, NOx , and NH3 emissions, concentrations of NH3 and NH4NO3 can be expected to continue to dominate the inorganic pollution load over the next decades, especially NH3, which is linked to substantial exceedances of ecological thresholds across Europe. The shift from (NH4)2SO4 to an atmosphere more abundant in NH4NO3 is expected to maintain a larger fraction of reactive N in the gas phase by partitioning to NH3 and HNO3 in warm weather, while NH4NO3 continues to contribute to exceedances of air quality limits for PM2.5

Markovian Dynamics on Complex Reaction Networks

Complex networks, comprised of individual elements that interact with each other through reaction channels, are ubiquitous across many scientific and engineering disciplines. Examples include biochemical, pharmacokinetic, epidemiological, ecological, social, neural, and multi-agent networks. A common approach to modeling such networks is by a master equation that governs the dynamic evolution of the joint probability mass function of the underling population process and naturally leads to Markovian dynamics for such process. Due however to the nonlinear nature of most reactions, the computation and analysis of the resulting stochastic population dynamics is a difficult task. This review article provides a coherent and comprehensive coverage of recently developed approaches and methods to tackle this problem. After reviewing a general framework for modeling Markovian reaction networks and giving specific examples, the authors present numerical and computational techniques capable of evaluating or approximating the solution of the master equation, discuss a recently developed approach for studying the stationary behavior of Markovian reaction networks using a potential energy landscape perspective, and provide an introduction to the emerging theory of thermodynamic analysis of such networks. Three representative problems of opinion formation, transcription regulation, and neural network dynamics are used as illustrative examples.Comment: 52 pages, 11 figures, for freely available MATLAB software, see http://www.cis.jhu.edu/~goutsias/CSS%20lab/software.htm

Air pollution trends in the EMEP region between 1990 and 2012

The present report synthesises the main features of the evolution over the 1990-2012 time period of the concentration and deposition of air pollutants relevant in the context of the Convention on Long-range Transboundary Air Pollution: (i) ozone, (ii) sulfur and nitrogen compounds and particulate matter, (iii) heavy metals and persistent organic pollutants. It is based on observations gathered in State Parties to the Convention within the EMEP monitoring network of regional background stations, as well as relevant modelling initiatives. Joint Report of: EMEP Task Force on Measurements and Modelling (TFMM), Chemical Co-ordinating Centre (CCC), Meteorological Synthesizing Centre-East (MSC-E), Meteorological Synthesizing Centre-West (MSC-W)

Solving the chemical master equation using sliding windows

<p>Abstract</p> <p>Background</p> <p>The chemical master equation (CME) is a system of ordinary differential equations that describes the evolution of a network of chemical reactions as a stochastic process. Its solution yields the probability density vector of the system at each point in time. Solving the CME numerically is in many cases computationally expensive or even infeasible as the number of reachable states can be very large or infinite. We introduce the sliding window method, which computes an approximate solution of the CME by performing a sequence of local analysis steps. In each step, only a manageable subset of states is considered, representing a "window" into the state space. In subsequent steps, the window follows the direction in which the probability mass moves, until the time period of interest has elapsed. We construct the window based on a deterministic approximation of the future behavior of the system by estimating upper and lower bounds on the populations of the chemical species.</p> <p>Results</p> <p>In order to show the effectiveness of our approach, we apply it to several examples previously described in the literature. The experimental results show that the proposed method speeds up the analysis considerably, compared to a global analysis, while still providing high accuracy.</p> <p>Conclusions</p> <p>The sliding window method is a novel approach to address the performance problems of numerical algorithms for the solution of the chemical master equation. The method efficiently approximates the probability distributions at the time points of interest for a variety of chemically reacting systems, including systems for which no upper bound on the population sizes of the chemical species is known a priori.</p

Gendered vocational identities – female students\u27 strategies for identity formation during workplace-based learning in male-dominated work

Purpose: This article investigates female vocational students\u27 strategies for becoming part of a workplace community, what these strategies are and how they are tied to the formation of vocational identities within male-dominated industrial work. Of particular interest is how female students enrolled on Swedish upper secondary industrial programmes experience workplace-based learning at industrial workplaces as part of their vocational education. The theoretical framework derives from Wenger\u27s concept of community of practice, but his theoretical concept does not explicitly include gender dimensions. Therefore, the concept of community of practice is also combined with Paechter\u27s assumption of gender, whereby femininity and masculinity can be considered as different communities of practice. Methods: The article draws on evidence from a Swedish study based on interviews with 20 female students enrolled on the industrial programme at six upper secondary schools. In this vocational programme, there is a distinct gender distribution and only a small minority of the students on the programme are girls. In the analysis, the focus is on the female students\u27 strategies used during workplace-based learning to become part of the work community which consists almost exclusively of male workers. Findings: The female students deliberately negotiated vocational identities as female industrial workers to become accepted in the male-dominated work community. The findings highlight three specific strategies that the female students used: Acting like gender does not matter, acting like boys (not like drama queens), and acting tough and joking around. The female students\u27 strategies were part of – and tied to – a complex vocational identity formation process that featured contradictory requirements. By taking individual responsibility, they identified relevant information for becoming industrial workers and chose to act like boys. The female students saw no problem with being a girl, yet they struggled with implicit, diffuse and hidden gender structures and prejudices in the male-dominated industrial companies. Nevertheless, they strived for what they perceived to be an attractive vocational identity as industrial workers; it was an alternative, atypically feminine way of being that attracted the female students. Conclusions: The study concludes that female students mostly rely on their individual agency when interacting with others in the male-dominated workplace community. A "gendered vocational identity" is formed which shows that the identity formation of female students is a complex double process, in which vocational and gender identities are formed simultaneously and in parallel within the male-dominated workplace. (DIPF/Orig.

Speaking of oral presentations : Primary school teachers’ perspective on scaffolding strategies for speaking activities in the teaching of Swedish

Föreliggande studie syftar till att undersöka vilka stödstrukturer lågstadielärare uppger att de bygger i klassrummet för att stötta organiserade samtal i svenskundervisningen. Studien tar sin utgångspunkt i den sociokulturella teorin där begreppet stödstruktur är centralt. Vidare har semistrukturerade intervjuer besvarats skriftligt av sju lågstadielärare och i analysen av empirin användes två kategoriseringar av stödstrukturer: intellektuella och fysiska (Säljö, 2000:100). De intellektuella stödstrukturer som framkom i studien är läraren som kommunikativ förebild, det sociala klassrumsklimatet, elevens självkänsla samt kamratlärande. De fysiska stödstrukturer som utkristalliserades i materialet var klassrumsmöblering, text- och bildstöd samt andra fysiska artefakter. Av dessa ansåg flertalet lärare att textoch bildstöd var den bäst fungerande stödstrukturen. Lärarens sätt att visa och vägleda eleverna till att föra samtal, det vill säga att vara en kommunikativ förebild, var ytterligare en stödstruktur som uppfattades som framgångsrik. Bland intervjusvaren nämndes tämligen få fysiska artefakter, vilket var ett oväntat resultat.

Speaking of oral presentations : Primary school teachers’ perspective on scaffolding strategies for speaking activities in the teaching of Swedish

Föreliggande studie syftar till att undersöka vilka stödstrukturer lågstadielärare uppger att de bygger i klassrummet för att stötta organiserade samtal i svenskundervisningen. Studien tar sin utgångspunkt i den sociokulturella teorin där begreppet stödstruktur är centralt. Vidare har semistrukturerade intervjuer besvarats skriftligt av sju lågstadielärare och i analysen av empirin användes två kategoriseringar av stödstrukturer: intellektuella och fysiska (Säljö, 2000:100). De intellektuella stödstrukturer som framkom i studien är läraren som kommunikativ förebild, det sociala klassrumsklimatet, elevens självkänsla samt kamratlärande. De fysiska stödstrukturer som utkristalliserades i materialet var klassrumsmöblering, text- och bildstöd samt andra fysiska artefakter. Av dessa ansåg flertalet lärare att textoch bildstöd var den bäst fungerande stödstrukturen. Lärarens sätt att visa och vägleda eleverna till att föra samtal, det vill säga att vara en kommunikativ förebild, var ytterligare en stödstruktur som uppfattades som framgångsrik. Bland intervjusvaren nämndes tämligen få fysiska artefakter, vilket var ett oväntat resultat.

Screening av nutritionsstatus hos kritiskt sjuka : en systematisk litteraturstudie

Syftet med denna studie var att kartlägga screeningsinstrument som mäter nutritionsstatus hos kritiskt sjuka samt se hur de används i vården. Studien genomfördes som en systematisk litteraturstudie. Artiklar söktes i databaserna Cinahl och Medline. Tretton artiklar identifierades, efter kvalitetsgranskning, till studien. I resultatet framkom flera nutritionsscreeningsinstrument och tre utav dessa; SGA, MUST och NRS 2002, var mer anpassade för screening av kritiskt sjuka. NRS 2002 hade av dessa tre högst specifitet, då instrumentet bedömer sjukdomens eller skadans svårhetsgrad som en risk för undernäring. Resultaten om hur screeningsinstrumenten används i vården visar att användandet av dessa instrument var sällsynt, rekommendationer följs inte. Orsaker till det är bland annat personalens attityder och kunskapsbrist, ansvarsfördelning och rutiner. Några sjuksköterskor föredrog att använda sig av egna bedömningar av patienternas nutritionsstatus. I studier där nutritionsförbättringsprojekt införts ökade nutritionsscreeningen och dokumentationen signifikant. Slutsatsen är att NRS 2002 är det nutritionsscreeningsinstrument som passar bäst för kritiskt sjuka. Screeningsinstrumenten används dock inte som rekommenderat och orsaker till det är bland annat personalens kunskapsbrist och attityder

Gendered Vocational Identities - Female Students' Strategies for Identity Formation During Workplace-Based Learning in Male-Dominated Work

Purpose: This article investigates female vocational students' strategies for becoming part of a workplace community, what these strategies are and how they are tied to the formation of vocational identities within male-dominated industrial work. Of particular interest is how female students enrolled on Swedish upper secondary industrial programmes experience workplace-based learning at industrial workplaces as part of their vocational education. The theoretical framework derives from Wenger's concept of community of practice, but his theoretical concept does not explicitly include gender dimensions. Therefore, the concept of community of practice is also combined with Paechter's assumption of gender, whereby femininity and masculinity can be considered as different communities of practice. Methods: The article draws on evidence from a Swedish study based on interviews with 20 female students enrolled on the industrial programme at six upper secondary schools. In this vocational programme, there is a distinct gender distribution and only a small minority of the students on the programme are girls. In the analysis, the focus is on the female students' strategies used during workplace-based learning to become part of the work community which consists almost exclusively of male workers. Findings: The female students deliberately negotiated vocational identities as female industrial workers to become accepted in the male-dominated work community. The findings highlight three specific strategies that the female students used: Acting like gender does not matter, acting like boys (not like drama queens), and acting tough and joking around. The female students' strategies were part of - and tied to - a complex vocational identity formation process that featured contradictory requirements. By taking individual responsibility, they identified relevant information for becoming industrial workers and chose to act like boys. The female students saw no problem with being a girl, yet they struggled with implicit, diffuse and hidden gender structures and prejudices in the male-dominated industrial companies. Nevertheless, they strived for what they perceived to be an attractive vocational identity as industrial workers; it was an alternative, atypically feminine way of being that attracted the female students. Conclusions: The study concludes that female students mostly rely on their individual agency when interacting with others in the male-dominated workplace community. A "gendered vocational identity" is formed which shows that the identity formation of female students is a complex double process, in which vocational and gender identities are formed simultaneously and in parallel within the male-dominated workplace

You can count on me : A qualitative study about teachers' perspective on collaborative learning in the teaching of mathematics

Föreliggande studie syftar till att undersöka och beskriva lärares inställning till grupparbete inom matematikundervisningen på lågstadiet. Dessutom studeras vilka metoder lågstadielärare säger sig använda vid arbete i grupp inom ämnet matematik, samt vilka av matematikens kunskapsområden som lämpar sig bäst för grupparbete enligt lärare. Studien tar sin utgångspunkt i den sociokulturella teorin där samarbetslärande är en central del. Vidare har empiri samlats in genom skriftliga semistrukturerade intervjuer med tio lågstadielärare och i analysen kategoriserades sedan svaren utifrån fyra sociokulturella begrepp: redskap, scaffolding, den proximala utvecklingszonen och metakognition. I studien framkom det att samtliga deltagare tillämpar grupparbete i matematikundervisningen vid ett eller flera tillfällen i veckan. Därtill lyfter lärarna en rad fördelar med arbetsformen och tolkas därför ha en positiv inställning till grupparbete i matematik. De arbetsformer som utkristalliserades i materialet var EPA, kompisrätta och lärpar. Av dessa ansåg flest lärare att EPA var en väl fungerande metod för arbete i grupp inom matematikundervisningen. De kunskapsområden som var mest framträdande i empirin var Problemlösning och Geometri. Dock understryker samtliga lärare att det inte finns något kunskapsområde inom matematik som bör undvikas helt vid arbete i grupp. Av de tio lärare som intervjuats uppgav samtliga att grupparbete är särskilt gynnsamt vid arbete med problemlösning medan sex av deltagarna framhöll geometri som ett lämpligt område för samarbetslärande