bluuebunny/crossref_metadata_2025 huggingface dataset:
SEROPREVALENCE OF CANINE MONOCYTIC EHRLICHIOSIS IN HUNTING DOGS IN THE AUTONOMOUS PROVINCE OF VOJVODINA, SERBIA
Authors: Potkonjak Aleksandar , Savić Sara , Spasojević Kosić Ljubica , Vračar Vuk , Kudus Radmila , Suvajdžić Ljiljana , Radišić Nenad
Published: June 2020

Canine monocytic ehrlichiosis is a bacterial, vector-transmitted infection caused by Ehrlichia canis. Th e pathogen is mainly transmitted by ticks Rhipicephalus sanguineus. The disease highest distributionis most widely distributed in tropical and subtropical countries but it is also reported in Mediterranean countries of Europe (Spain, France, Italy, Turkey). Temperate continental climate and presence of these tick species are responsible for the maintenance and spreading of canine monocytic ehrlichiosis within the dog population in our region as well. Since hunting dogs are more exposed to tick bites then pet dogs, ed thisour study was conducted with the aims of determining the seroprevalence and basic epidemiological characteristics of monocytic ehrlichiosis infection in the population of hunting dogs, and comparing the obtained results with the results of other authors. This research involved 58 hunting dogs from the region of Autonomous Province of Vojvodina. All dogs were clinically examined and their basic epidemiological characteristics were recorded. Then, blood samples were collected in order to determine the presence of specifi c G class antibodies against Ehrlichia canis antigens. An indirect immunofl uorescence test manufactured by VMRD, U.S.A., was used. In this study, the seroprevalence of monocytic ehrlichiosis in a population of examined hunting dogs from the region of Vojvodina was 13.79%. Th is rate is similar to the seroprevalence of monocytic ehrlichiosis in the general population of dogs in Vojvodina.
CORYNEBACTERIUM RENALE CYSTITIS IN COW - CASE REPORT -
Authors: Milanov Dubravka , Velhner Maja , Suvajdžić Ljiljana , Bojkovski Jovan
Published: June 2020

Corynebacterium renale is a common inhabitant of the the vulva, vagina and prepuce of apparently normal cattle, but also an opportunistic pathogen and the cause of cystitis and purulent pyelonephritis in cows. In this paper, we show the isolation of C. renale from the urine of cows with clinical cystitis, colonial, microscopic and biochemical characteristics of the isolates, relevant data on virulence factors, clinical manifestations of diseaseand basic principles of therapy.
INVESTIGATION OF PRESENCE OF METHICILLIN RESISTANT STAPHYLOCOCCI IN STUDENTS OF THE FACULTY OF VETERINARY MEDICINE AT THE UNIVERSITY OF BELGRADE
Authors: Rađenović Milan , Ašanin Jelena , Aksentijević Ksenija , Mišić Dušan
Published: June 2020

Resistance to methicillin in staphylococci is considered to be one of the most dangerous forms of bacterial resistances to antibiotics. Methicillinresistant staphylococci (MRS) are zoonotic agents which cause local and systemic infections in humans and animals, oft en with a fatal outcome due to the absence of adequate antibiotic therapy. People colonized with strains of MRS are asymptomatic carriers and reservoirs of these strains in human populations. Th e aim of this research was to determine the prevalence of strains of MRS among clinically healthy students of the Faculty of Veterinary Medicine in Belgrade. Th e study was conducted on 100 volunteers: 62 males and 38 females. Given that staphylococci are expected to be found in the highest percentage in the nose and on the armpit skin, the swabs were taken from these regions of each person. Blood agar was innoculated immediately on taking the swabs Aft er the incubation and isolation, the staphylococci were identifi ed to species level. Their susceptibility to methicillin was tested in a disk-diff usion test with cefoxitin. All strains which were found to be resistant to cefoxitin were investigated for the presence of mecA gene with PCR. Staphylococci were isolated in 146 out of the 200 swabs taken: there were 79 nose swabs and 67 axillar swabs positive for these bacteria. Seventeen isolates were resistant to cefoxitin and the presence of the mecA gene was confi rmed in seven, four of which were taken from the nose and three from the axillary region. The results of this research show that, being 6%, the prevalence of mecA-positive staphylococci in the population of clinically healthy students of veterinary medicine is significant. Th e percentage of methicillin-resistant staphylococci was higher in nose than in the axillar region of the students.
ExPro as psycho-affective stimulators through experiential marketing in nonprofit organizations
Authors: Gonzalez Díaz Romel Ramón , Acosta Moltó Elsa María
Published: June 2020

Este artículo tiene como objetivo analizar la relación de los proveedores de experiencia (ExPro) como estimuladores psicoafectivos del marketing experiencial en organizaciones sin fines de lucro de la región del Caribe colombiano; se enmarcó en la metodología complementaria, de tipo correlacional y diseño no experimental, transaccional, de campo. Durante el periodo comprendido del 1 de enero/2018 al 30 de noviembre/2018; se aplicó un cuestionario de escala Likert, validado a discreción de 5 expertos y con un coeficiente alfa de Cronbach 0.85 (Muy alto); dirigido a una población de 273 jóvenes entre 18 y 25 años en los departamentos de Córdoba y Sucre intervenidos socialmente por 5 fundaciones. Los datos estadísticos se procesaron en Microsoft Excel2010, SPSS v25 y @risk (método Montecarlo), posteriormente los resultados fueron discutidos e interpretados con 3 expertos en marketing, a través del método hermenéutico o interpretativo; se utilizó como herramienta para el análisis cualitativo el software Atlas.ti8, generando criterios para la ponderación y diseño de reglas de inferencia en el módulo de lógica difusa (Matlab2017), para obtener los siguientes resultados: desviación estándar de 0.23982, correlación entre variables de 0.666 (moderadamente positiva). En consecuencia, se generaron 7 normas para el módulo de inferencia para simplicar de 5 categorías de la escala Likert a 3 categorías según su proporcionalidad: Fuerte: 3.41 - 5.00, Medio: 2.61 - 3.40 y Débil: 1.00 - 2.60; como hallazgo significativo, el personal interno (Expro) genera una mayor influencia entre los estimuladores psico-afectivos, en las organizaciones sin fines de lucro.
Design of an Automatic Window Using a PIC Microcontroller and Stepper Motor
Authors: Okomba Nnamdi S , Okwor Candidus O , Adeyanju Ibrahim A , Ezea Hilary
Published: June 2020

In this paper, the design of an automatic window is presented. The proposed window closes and opens automatically during and after a rainfall. The automatic system was developed with a focus on hospitals in order to allow medical staff and other supporting staff to concentrate on their primary responsibilities of taking care of patients. The system design includes a PIC16F877A microcontroller which gets activated when a moisture detector sensor sends a high logic signal to it. The microcontroller executes its embedded program by activating the stepper motor through a ULN2003 current-dependent integrated circuit (IC) chip resulting in stepwise control of the window. Hence, the window is automatically closed when rainfall is detected but opens and remains open when no rain is detected. We intend to extend our design to automatic opening and closing of the windows at others times in addition to during and after rainfall; for instance, window opening and closing every day at specific times in the morning and evening respectively.
Design and Performance Evaluation of a Mixed-Mode Solar Crop Dryer
Authors: Abubakar Shitu , Umaru Samaila , Anafi Fatai O , Abubakar Aminu S
Published: June 2020

This study is concerned with development and performance evaluation of a mixed-mode solar  yam dryer. It was done to address the problems of uneven drying of product on different trays coordinate position in a typical indirect multiple trays dryer. Solar energy drying system was designed using the meteorological conditions of Zaria, Nigeria to dry yam slices in the mixed-mode natural convection. The dryer was designed to dry (7 kg) of yam slices. The dimensions of the dryer were: collector length, collector area, height of the drying chamber, chimney height, length of the drying chamber, and Width of the drying chamber were 0.65 m, 0.27 m2, 0.9 m, 0.7 m, 0.5 m, and 0.43 m, respectively. The solar yam dryer was exposed to solar radiation from 10:00 am to 06:00 pm and tested without load and with yam chips of 5 mm average thickness. Meteorological conditions were monitored during the dehydration process. The average drying rate, collector efficiency and drying efficiency were 2.55 kg/s, 42.20% and 25.35%, respectively. The results of performance evaluation of the solar dryer showed that the drying rate decreases by 3% and 8% in the second and third trays relative to the first tray. This shows that the drying rates did not vary significantly with the coordinate positions of the trays.
Comparative Analysis of Selected Heterogeneous Classifiers for Software Defects Prediction Using Filter-Based Feature Selection Methods
Authors: Akintola Abimbola G , Balogun Abdullateef , Lafenwa-Balogun Fatimah B , Mojeed Hameed A
Published: June 2020

Classification techniques is a popular approach to predict software defects and it involves categorizing modules, which is represented by a set of metrics or code attributes into fault prone (FP) and non-fault prone (NFP) by means of a classification model. Nevertheless, there is existence of low quality, unreliable, redundant and noisy data which negatively affect the process of observing knowledge and useful pattern. Therefore, researchers need to retrieve relevant data from huge records using feature selection methods. Feature selection is the process of identifying the most relevant attributes and removing the redundant and irrelevant attributes. In this study, the researchers investigated the effect of filter feature selection on classification techniques in software defects prediction. Ten publicly available datasets of NASA and Metric Data Program software repository were used. The topmost discriminatory attributes of the dataset were evaluated using Principal Component Analysis (PCA), CFS and FilterSubsetEval. The datasets were classified by the selected classifiers which were carefully selected based on heterogeneity. Naïve Bayes was selected from Bayes category Classifier, KNN was selected from Instance Based Learner category, J48 Decision Tree from Trees Function classifier and Multilayer perceptron was selected from the neural network classifiers. The experimental results revealed that the application of feature selection to datasets before classification in software defects prediction is better and should be encouraged and Multilayer perceptron with FilterSubsetEval had the best accuracy. It can be concluded that feature selection methods are capable of improving the performance of learning algorithms in software defects prediction.
Modelling of an Electric Power Grid for New Power Plant Evacuation
Authors: Adetona Sunday , Ugwuagbo Emenike , Okafor Frank , Akinbulire Tolulope
Published: June 2020

Injection of a new power system component into an existing power grid often cause change in the behaviour of the power grid to which it is injected. Therefore, forecasting possible unsafe condition(s) of the power grid using an efficient power study tool is essential; and, provision of necessary mitigation actions to ensure a reliable grid is important. This paper, therefore, presents evacuation study of a 400 MW power plant connecting to the 15 GW planned transmission network of the Transmission Company of Nigeria (TCN). The NEPLAN power system analytical software was used in the modelling and simulation of the electric power grid. In the research, load flow, short circuit, transient stability, and contingency analyses were performed on the case study. From the short circuit study, it is observed that if TCN network expansion program is fully implemented, the short circuit level will go beyond the existing switchgear ratings in major substations of the network. However, with the introduction of substation splitting at Omotoso and ongoing Ogijo substations, the short circuit level will be reduced by 15%; leading to improvement in the overall system stability. Keywords—Load flow, short circuit study, transient stability study, and contingency analysis
Geotechnical Assessment of Pavement Failure along Lagos-Ibadan Expressway
Authors: Odunfa Simeon O , Owolabi Adebayo O. , Aiyedun Peter O. , Sadiq Obanisola M.
Published: June 2020

Pavement failure has contributed immensely to loss of lives, disruption to normal daily activities and increase amount of money being spent on maintenance annually. One of the causes is associated with inadequate investigations on subgrade materials. This study aimed at examining the geotechnical parameters as factors of pavement failure along Lagos–Ibadan Expressway. Samples were collected at the failed and stable portions on some selected road segments and subjected to laboratory tests including Natural Moisture Content (NMC), Linear Shrinkage(LS), particle size distribution and California Bearing Ratio(CBR). The NMC along the failed sections was on the high side (ranged from 13.11% to 26.89%) compared with the stable sections (ranged from 11.11% to 16.40%). Most of the tested soils have percentage passing 0.075mm sieve more than 35% maximum required by the Federal Ministry of Works and Housing for subgrade materials. The maximum dry density(MDD) for the samples at failed and stable sections ranged from 1550 kg/m3 to 1860 kg/m3; 1650 kg/m3 to 1980 kg/m3 respectively while the Optimum Moisture Content(OMC) ranged from 8.30% to 20.30%. The soaked CBR values ranged from 2% to 17% while the unsoaked values ranged from 4% to 25%. The increase in NMC along the failed portions could be as a result of high water table along these sections. Some of the materials at failed locations had values of LS > 8% which suggests high susceptibility to shrinkage and swelling which results in differential settlement and contributed to pavement failure along these sections of the road. Keywords: Geotechnical, Pavement failures, subsurface investigations, Expressway, subgrade materials.
Effect of Ripe and Unripe Plantain Peel Ash on Concrete Workability and Compressive Strength
Authors: Adetayo Oluwaseun A , Jubril Olatunji
Published: June 2020

Plantain (Musa paradisiaca) peels are by-product of plantain fruits, constituting about 40% of the fruits. Performance effects of Ripe Plantain peel ash (RPPA) and Unripe Plantain peel ash (UPPA) in concrete were investigated in this research. Both RPPA and UPPA were added to the concrete as admixture in the proportion of 1.5% and 2.5%. The percentage composition of Silica (SiO2) and Alumina (Al2O3) contents in RPPA and UPPA were determined using spectrometry method of analysis. Slump test on the fresh concrete and compressive strength test were carried out on the concrete cube for 7, 14, 28, 56 and 90 days. The Silica (SiO2) content for RPPA and UPPA were 46.37% and 54.00% respectively while the Alumina (Al2O3) content for RPPA and UPPA were 2.20% and 3.08% respectively. The compressive strength for the control mix at 28-day is 20.4N/mm2, while that of 1.5 and 2.5% RPPP are 16.3 and 14.0N/mm2 respectively representing decrease of 20.15 and 31.58% respectively, compressive strength results for concrete containing 1.5 and 2.5% UPPA are 14.4 and 12.2N/mm2 respectively representing decrease of 29.32 and 40.01% respectively with the control mix. At later age, the strength development is observed to be on the increase with concrete containing admixtures. At 90-day, control sample has strength of 23.32N/mm2 which is about 12.56% higher than 28-day strength, concrete with 1.5 and 2.5% RRPA have strength of 22.77N/mm2 (28.50% increase), 20.64N/mm2 (32.40% increase) respectively while 1.5 and 2.5% UPPA concrete have strength of 20.86N/mm2 (31.00% increase) and 19.02N/mm2 (35.70% increase). Keywords---- Admixture, Compressive strength, Ripe plantain peel, Unripe plantain peel, Workability.
Social- Economic Assessment and Profitability of Artisanal Gold Miners in Niger State, Nigeria
Authors: Melodi Mbuyi M , Ajibade Ganiyu W
Published: June 2020

This study centers on socio-economic assessment and profitability of artisanal gold miners in Niger State, Nigeria. The specific objectives are to examine artisanal gold miners’ socio-economic profile, examine the level of profitability of artisanal gold mining and identify the constraints determining the profitability of artisanal gold mining. Primary data was used which were obtained through the administration of structured questionnaires to randomly sampled artisanal gold miners in the study area. Descriptive statistics using charts, frequency table, mean, maximum, minimum and range, and inferential statistics using multiple linear regression, t-test were used as well as budgetary analysis. Profit difference of N 16,139.69 was noted between male and female artisan gold miners, with male earning a non-significantly (p>0.05) higher profit than the female artisans. Married artisan spent significantly (p<0.05) more (N106, 549.66) in running their various artisanal duties than the unmarried single artisans (N 87,036.67). Single artisans were noted to earn higher revenue than their married counterpart. This significant difference of N 20,897.09 can be accounted for by the ready availability of single unmarried artisans to work for longer hours per day without any distraction of family cares and obligations. This invariably leads to the significantly higher profit of single unmarried artisanal miners of N97, 051. Other significant determinants of artisanal gold profit level are miners’ age in years (p<0.01), experience at work in years (p<0.10) and years of work at current mine (p<0.05). Findings shows that  artisanal miners were noted to be operating profitably in the study location; however, marital status, age of miners, years of experience and years of work in the current mine were found to be significant determinants of profitability and profit level of an average miners.  Keywords – Profitability, Artisanal gold, Revenue, Socio-economic profile, constraints.
Liderazgo interpersonal y clima organizacional en el Departamento de enfermería de un hospital público
Authors: Morales-Malpartida Rosa L.
Published: June 2020

El objetivo de la presente investigación fue determinar la relación entre el liderazgo interpersonal y el clima organizacional percibida por los profesionales de enfermería del Hospital II-E Materno Infantil Carlos Showing Ferrari de Huánuco, durante el 2018. Fue un estudio con enfoque cuantitativo, de tipo relacional, descriptivo, prospectivo y transversal, con una población muestral de 43 enfermeras seleccionadas no probabilísticamente, quienes respondieron los cuestionarios de liderazgo interpersonal y clima organizacional, previamente validadas y fiabilizadas. Se aplicaron las consideraciones éticas. Se realizó el análisis descriptivo y la hipótesis se comprobó mediante la prueba no paramétrica Rho de Spearman para un p ≤ 0,05. Los resultados muestran que 55,8% (24) de la muestra percibieron un liderazgo interpersonal de nivel moderado, 34,9% (15) alto y 9,3% (4) bajo. El 51,2% (22) percibieron un clima organizacional por mejorar, 34,9% (15) saludable y 14% (6) no saludable. Se comprobó la existencia de relación positiva y significativa entre el trabajo en equipo y entre las destrezas gerenciales del liderazgo interpersonal y el clima organizacional [rs = 0,817 y rs = 0,654, con p<0,05 respectivamente]. Se concluye que el liderazgo interpersonal y clima organizacional percibida por los profesionales de enfermería del Hospital II-E Materno Infantil Carlos Showing Ferrari, Huánuco – 2018, están relacionadas significativamente.
Gestión de la prevención de riesgos en el trabajo y el estado de salud autopercibida
Authors: Garay-Cabrera Gianny R. , Velásquez-Rondón Sonia
Published: June 2020

La investigación tuvo el objetivo de relacionar la gestión de la prevención de riesgos en el trabajo con el estado de salud auto-percibida por los profesionales de enfermería de un Hospital Público de Huánuco en el 2018. Fue un estudio cuantitativo, analítico, prospectivo, transversal y de diseño correlacional, con una población muestral de 46 enfermeros, quienes respondieron satisfactoriamente los instrumentos documentales previamente validados y confiables. Se realizó el análisis descriptivo y la hipótesis de contrastó mediante la Chi cuadrada; para un nivel de confianza de 95% y p ≤ 0,05. Los resultados indican que el nivel de gestión de la prevención de riesgos en el trabajo fue percibido por la mayoría de la muestra en el nivel moderado [71,7%(33)], que implica que en cierto modo se realizaban el  diseño de planes de prevención de riesgos, cuentan con cierta capacidad de gestión de prevención de riesgos, realizan controles médicos planificados, acciones de protección laboral, cobertura de vacunación, información y capacitación de la prevención de riesgos e información preventiva de las Aseguradoras de Riesgos del Trabajo. El estado de salud física fue percibida como mejor [76.1% (35)], mientras que el estado de salud mental fue percibido de rango peor [89.1% (41)]. Se concluye que la gestión de la prevención de riesgos en el trabajo se relaciona con el estado de salud física y mental auto-percibida por los profesionales de enfermería. Es decir, dado la gestión de prevención de riesgos de nivel moderado la percepción del estado de salud es peor y viceversa.
A educação profissional dos jovens e a modernidade brasileira no início do século XX
Authors: Queiroz Edna Mendonça Oliveira de , Pinheiro Rafael Gomes , Figueiredo Túlio Marcel Rufino de Vasconcelos
Published: June 2020

Apresentam-se, neste artigo, os resultados de um estudo histórico-documental que analisou a nova conjuntura social, política e econômica exigida pelo processo de modernização em curso no Brasil Republicano e a educação profissional diante do acirramento das relações de poder, no contexto da Primeira República. Teve como objetivo investigar os nexos constitutivos das relações entre a educação profissional destinada aos jovens e os processos sociais nas primeiras décadas do século XX. A atuação do Estado voltada para a educação dos jovens se configurou como um instrumento de formação de novas subjetividades para um novo tipo de trabalho que se constituía e como uma forma de controle social sobre a população empobrecida. Expressão da “modernização conservadora”, a educação propunha aos jovens a inserção social enquanto os subjugava às relações econômicas impostas na trilha do capitalismo que se estabelecia.
Gamificação no ensino de línguas
Authors: Leffa Vilson Jose
Published: June 2020

Os jogos digitais têm despertado o interesse dos pesquisadores na área do ensino de línguas como recurso de aprendizagem para os alunos, seja de modo indireto, quando o aluno joga para se divertir e incidentalmente acaba aprendendo a língua; seja de modo direto, quando o aluno joga com o objetivo explícito de aprender a língua, usando, no entanto, uma atividade gamificada, adaptada para simular um jogo digital, com a inclusão de pontos, troféus e quadros de liderança (PBL, em inglês). O objetivo deste artigo é investigar a influência da gamificação na aprendizagem de línguas, considerando a reação e o engajamento do aluno. Parte-se para isso da perspectiva dos Letramentos Digitais, como arcabouço teórico maior, e da Teoria do Fluxo, como base metodológica, para tentar explicar o envolvimento do aluno nas atividades. Os dados foram gerados a partir de uma perspectiva quanti-qualitativa, incluindo a elaboração de um sistema autoral de gamificação (ELO), aplicação do sistema em aulas de língua inglesa, entrevistas grupais, sessões de observação, questionários sociodemográficos e a escala Likert. Os resultados mostraram que o aspecto que mais pesou para o engajamento do aluno foi a relevância do conteúdo, seguido do design didático da atividade, ficando, em terceiro lugar, a gamificação, com base nos PBL. A conclusão é de que, para engajar o aluno com a gamificação, é necessário ir além dos PBL, incluindo aí a questão do prazer, da persistência e da superação, que devem ser despertados pelas atividades feitas pelo aluno.
Variability and past long-term changes of brominated very short-lived substances at the tropical tropopause
Authors: Tegtmeier Susann , Atlas Elliot , Quack Birgit , Ziska Franziska , Krüger Kirstin
Published: June 2020

Abstract. Halogenated very short-lived substances (VSLSs), such as bromoform
(CHBr3), can be transported to the stratosphere and contribute to the
halogen loading and ozone depletion. Given their highly variable emission
rates and their short atmospheric lifetimes, the exact amount as well as the
spatio-temporal variability of their contribution to the stratospheric halogen
loading are still uncertain. We combine observational data sets with
Lagrangian atmospheric modelling in order to analyse the spatial and
temporal variability of the CHBr3 injection into the stratosphere for
the time period 1979–2013. Regional maxima with mixing ratios of up to
0.4–0.5 ppt at 17 km altitude are diagnosed to be over Central America (1) and over the Maritime Continent–west Pacific (2), both of which are
confirmed by high-altitude aircraft campaigns. The CHBr3 maximum over
Central America is caused by the co-occurrence of convectively driven short
transport timescales and strong regional sources, which in conjunction
drive the seasonality of CHBr3 injection. Model results at a daily
resolution reveal isolated, exceptionally high CHBr3 values in this
region which are confirmed by aircraft measurements during the ACCENT
campaign and do not occur in spatially or temporally averaged model fields.
CHBr3 injection over the west Pacific is centred south of the Equator
due to strong oceanic sources underneath prescribed by the here-applied
bottom-up emission inventory. The globally largest CHBr3 mixing ratios
at the cold point level of up to 0.6 ppt are diagnosed to occur over the
region of India, Bay of Bengal, and Arabian Sea (3); however, no data from
aircraft campaigns are available to confirm this finding. Inter-annual
variability of stratospheric CHBr3 injection of 10 %–20 % is to a large
part driven by the variability of coupled ocean–atmosphere circulation
systems. Long-term changes, on the other hand, correlate with the regional
sea surface temperature trends resulting in positive trends of stratospheric CHBr3
injection over the west Pacific and Asian monsoon region and negative trends
over the east Pacific. For the tropical mean, these opposite regional trends
balance each other out, resulting in a relatively weak positive trend of
0.017±0.012 ppt Br per decade for 1979–2013, corresponding to 3 % Br per decade. The overall contribution of CHBr3 together with
CH2Br2 to the stratospheric halogen loading accounts for 4.7 ppt Br, in good agreement with existing studies, with 50 % and 50 % being
injected in the form of source and product gases, respectively.
Influence of aromatics on tropospheric gas-phase composition
Authors: Taraborrelli Domenico , Cabrera-Perez David , Bacer Sara , Gromov Sergey , Lelieveld Jos , Sander Rolf , Pozzer Andrea
Published: June 2020

Abstract. Aromatics contribute a significant fraction to organic compounds in the troposphere and are mainly emitted by anthropogenic activities and biomass burning. Their oxidation in lab experiments is known to lead to the formation of ozone and aerosol precursors. However, their overall impact on tropospheric composition is uncertain as it depends on transport, multiphase chemistry, and removal processes of the oxidation intermediates. Representation of aromatics in global atmospheric models has been either neglected or highly simplified. Here, we present an assessment of their impact on the gas-phase chemistry, using the general circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry). We employ a comprehensive kinetic model to represent the oxidation of the following monocyclic aromatics: benzene, toluene, xylenes, phenol, styrene, ethylbenzene, trimethylbenzenes, benzaldehyde, and lumped higher aromatics that contain more than 9 C atoms. Significant regional changes are identified for several species. For instance, glyoxal increases by 130 % in Europe and 260 % in East Asia, respectively. Large increases in HCHO are also predicted in these regions. In general, the influence of aromatics is particularly evident in areas with high concentrations of NOx, with increases up to 12 % in O3 and 17 % in OH. On a global scale, the estimated net changes are minor when aromatic compounds are included in our model. For instance, the tropospheric burden of CO increases by about 6 %, while the burdens of OH, O3, and NOx (NO + NO2) decrease between 3 % and 9 %. The global mean changes are small, partially because of compensating effects between high- and low-NOx regions. The largest change is predicted for the important aerosol precursor glyoxal, which increases globally by 36 %. In contrast to other studies, the net change in tropospheric ozone is predicted to be negative, −3 % globally. This change is larger in the northern hemisphere where global models usually show positive biases. We find that the reaction with phenoxy radicals is a significant loss for ozone, of the order of 200–300 Tg/yr, which is similar to the estimated ozone loss due to bromine chemistry. Although the net global impact of aromatics is limited, our results indicate that aromatics can strongly influence tropospheric chemistry on a regional scale, most significantly in East Asia. An analysis of the main model uncertainties related to oxidation and emissions suggests that the impact of aromatics may even be significantly larger.
Ship-based measurements of ice nuclei concentrations over the
Arctic, Atlantic, Pacific and Southern Ocean
Authors: Welti André , Bigg E. Keith , DeMott Paul J. , Gong Xianda , Hartmann Markus , Harvey Mike , Henning Silvia , Herenz Paul , Hill Thomas C. J. , Hornblow Blake , Leck Caroline , Löffler Mareike , McCluskey Christina S. , Rauker Anne Marie , Schmale Julia , Tatzelt Christian , van Pinxteren Manuela , Stratmann Frank
Published: June 2020

Abstract. Ambient concentrations of ice-forming particles measured during ship expeditions are collected and summarized with the aim of establishing a spatial distribution and variability of ice nuclei in oceanic regions. The presented data from literature and previously unpublished data from over 23 months of ship-based measurements stretch from the Arctic to the Southern Ocean and include a circumnavigation of Antarctica. In comparison to continental observations, ship-based measurements of ambient ice nuclei show one to two order of magnitude lower mean concentrations. To quantify the geographical variability in oceanic areas, the concentration range of potential ice nuclei in different climate zones is analysed by meridionally dividing the expedition tracks into: tropical, temperate and polar climate zones. We find that concentrations of ice nuclei in these meridional zones follow temperature spectra with similar slope, but vary in absolute concentration. Typically, the frequency with which specific concentrations of ice nuclei are observed at a certain temperature follows a log-normal distribution. A consequence of the log-normal distribution is that the mean concentration is higher than the most frequently measured concentration. Finally, the potential contribution of ship exhaust to the measured ice nuclei concentration on board of research-vessels is analysed as function of temperature. We find a sharp onset of the influence at approximately −36 °C, but none at warmer temperatures that could bias ship-based measurements.
Spatiotemporal variability of elemental and organic carbon in
Svalbard snow during 2007–2018
Authors: Zdanowicz Christian , Gallet Jean-Charles , Björkman Mats P. , Larose Catherine , Schuler Thomas V. , Luks Bartłomiej , Koziol Krystyna , Spolaor Andrea , Barbaro Elena , Martma Tõnu , van Pelt Ward , Wideqvist Ulla , Ström Johan
Published: June 2020

Abstract. Light-absorbing carbonaceous aerosols emitted by biomass or fossil fuel combustion can contribute to amplify Arctic climate warming by lowering the albedo of snow. The Svalbard archipelago, being near to Europe and Russia, is particularly affected by these pollutants, and improved knowledge of their distribution in snow is needed to assess their impact. Here we present and synthesize new data obtained on Svalbard between 2007 and 2018, comprising 324 measurements of elemental (EC) and organic carbon (OC) in snow from 49 sites. We used these data, combined with meteorological and aerosol data and snowpack modelling, to investigate the variability of EC and OC deposition in Svalbard snow across latitude, longitude, elevation and time. Overall, EC concentrations (CsnowEC) ranged from
Ideas and perspectives: enhancing the impact of the FLUXNET network of eddy covariance sites
Authors: Papale Dario
Published: June 2020

Abstract. In the last 20 years, the FLUXNET network provided unique measurements of CO2, energy and other greenhouse gases exchange between ecosystems and atmosphere measured with the eddy covariance technique. These data have been widely used in different and heterogeneous applications and FLUXNET became a reference source of information not only for ecological studies but also in modeling and remote sensing applications. The data are in general collected, processed and shared by regional networks or by single sites and for this reason it is difficult for users interested to analysis involving multiple sites to easily access a coherent and standardized dataset. For this reason, periodic FLUXNET collections have been released in the last 15 years, every 5 to 10 years, with data standardized and shared under the same data use policy. However, the new tools available for data analysis and the need to constantly monitor the relations between ecosystem behaviour and climate change, require a reorganization of FLUXNET in order to increase the data interoperability, reduce the delay in the data sharing and facilitate the data use. All this keeping in mind the large effort made by the site teams to collect these unique data and respecting the different regional and national networks organization and data policies. Here a proposal for a new organization of FLUXNET is presented, where the regional and national networks become the pillars of the global initiative, organizing clusters and becoming responsible for the processing and preparation of datasets that users will be able to access real time and with a machine-to-machine tool, obtaining always the most updated collection possible but keeping high standardization and common data policy. This will also lead to an increase of the FAIRness (Findability, Accessibility, Interoperability and Reusability) of the FLUXNET data that would ensure a larger impact of the unique data produced and a proper data management and traceability.
Application and evaluation of the dendroclimatic process-based model MAIDEN during the last century in Canada and Europe
Authors: Rezsöhazy Jeanne , Goosse Hugues , Guiot Joël , Gennaretti Fabio , Boucher Etienne , André Frédéric , Jonard Mathieu
Published: June 2020

Abstract. Tree-ring archives are one of the main sources of information to
reconstruct climate variations over the last millennium with annual
resolution. The links between tree-ring proxies and climate have
usually been estimated using statistical approaches, assuming linear
and stationary relationships. Both assumptions may be inadequate, but
this issue can be overcome by ecophysiological modelling based on
mechanistic understanding. In this respect, the model MAIDEN (Modeling
and Analysis In DENdroecology) simulating tree-ring growth from daily
temperature and precipitation, considering carbon assimilation and
allocation in forest stands, may constitute a valuable tool. However,
the lack of local meteorological data and the limited characterization
of tree species traits can complicate the calibration and validation
of such a complex model, which may hamper palaeoclimate applications. The
goal of this study is to test the applicability of the MAIDEN model in
a palaeoclimate context using as a test case tree-ring observations
covering the 20th century from 21 Eastern Canadian taiga
sites and 3 European sites. More specifically, we investigate the
model sensitivity to parameter calibration and to the quality of
climatic inputs, and we evaluate the model performance using a validation
procedure. We also examine the added value of using MAIDEN in
palaeoclimate applications compared to a simpler tree-growth model, i.e.
VS-Lite. A Bayesian calibration of the most sensitive model parameters
provides good results at most of the selected sites with high
correlations between simulated and observed tree growth. Although
MAIDEN is found to be sensitive to the quality of the climatic inputs,
simple bias correction and downscaling techniques of these data
improve significantly the performance of the model. The split-sample
validation of MAIDEN gives encouraging results but requires long
tree ring and meteorological series to give robust results. We also
highlight a risk of overfitting in the calibration of model parameters
that increases with short series. Finally, MAIDEN has shown higher
calibration and validation correlations in most cases compared to
VS-Lite. Nevertheless, this latter model turns out to be more stable
over calibration and validation periods. Our results provide
a protocol for the application of MAIDEN to potentially any site with
tree-ring width data in the extratropical region.
Ice sheet and palaeoclimate controls on drainage network evolution: an example from Dogger Bank, North Sea
Authors: Emery Andy R. , Hodgson David M. , Barlow Natasha L. M. , Carrivick Jonathan L. , Cotterill Carol J. , Richardson Janet , Ivanovic Ruza , Mellett Claire
Published: June 2020

Abstract. Submerged landscapes on continental shelves archive drainage networks formed during periods of sea-level lowstand. The evolution of these postglacial drainage networks also reveals how past climate changes affected the landscape. Ice-marginal and paraglacial drainage networks on low-relief topography are susceptible to reorganisation of water supply, forced by ice-marginal rearrangement, precipitation and temperature variations, and marine inundation. A rare geological archive of climate-driven landscape evolution during the transition from ice-marginal (c. 23 ka BP) to a fully submerged marine environment (c. 8 ka BP) is preserved at Dogger Bank, in the southern North Sea. In this study, our analysis of high-resolution seismic reflection and Cone Penetration Test data reveal a channel network over a 1330 km2 area that incised glacial and proglacial lake-fill sediments. The channel network sits below coastal and shallow marine sediments, and is therefore interpreted to represent terrestrial drainage network. When mapped out, the channel form morphology reveals two distinct sets. The first set comprise two low sinuosity, wide (> 400 m) channels that contain macroforms of braid and side bars. These channels are interpreted to have originated as proglacial rivers, which drained the ice-sheet margin to the north. The second set of channels (75–200 m wide, with one larger, ~ 400 m wide) have higher sinuosity and form a sub-dendritic network of tributaries to the proglacial channels. The timing of channel formation lacks chronostratigraphic control. However, the proglacial rivers must have formed as the ice sheet was still on Dogger Bank, before 23 ka BP, to supply meltwater to the rivers. Ice-sheet retreat from Dogger Bank led to reorganisation of meltwater drainage and abandonment of the proglacial rivers. Palaeoclimate simulations show a cold and dry period at Dogger Bank between 23 and 17 ka BP. After 17 ka BP, precipitation increased, and drainage of precipitation formed the second set of channels. The second set of rivers remained active until marine transgression of Dogger Bank at c. 8 ka BP. Overall, this study provides a detailed insight into the evolution of river networks across Dogger Bank, and highlights the interplay between external (climate) and internal (local) forcings in drainage network evolution.
Short Communication: Optimizing UAV-SfM based topographic change detection with survey co-alignment
Authors: de Haas Tjalling , Nijland Wiebe , McArdell Brian W. , Kalthof Maurice W. M. L.
Published: June 2020

Abstract. High-quality digital surface models (DSMs) generated from structure-from-motion (SfM) based on imagery captured from unmanned aerial vehicles (UAVs), are increasingly used for topographic change detection. Classically, DSMs were generated for each survey individually and then compared to quantify topographic change, but recently it was shown that co-aligning the images of multiple surveys may enhance the accuracy of topographic change detection. Here, we use nine surveys over the Illgraben debris-flow torrent in the Swiss Alps to compare the accuracy of three approaches for UAV-SfM topographic change detection: (1) the classical approach where each survey is processed individually using ground control points (GCPs), (2) co-alignment of all surveys without GCPs, and (3) co-alignment of all surveys with GCPs. We demonstrate that compared to the classical approach co-alignment enhances the accuracy of topographic change detection by a factor 4 with GCPs and a factor 3 without GCPs, leading to xy and z offsets
Simulated wind farm wake sensitivity to configuration choices in the Weather Research and Forecasting model version 3.8.1
Authors: Tomaszewski Jessica M. , Lundquist Julie K.
Published: June 2020

Abstract. Wakes from wind farms can extend over 50 km downwind in stably stratified conditions. These wakes can undermine power production at downwind turbines, adversely impacting revenue. As such, wind farm wake impacts must be considered in wind resource assessments, especially in regions of dense wind farm development. The open-source Weather Research and Forecasting (WRF) numerical weather prediction model includes a wind farm parameterization to estimate wind farm wake effects, but model configuration choices can influence the resulting predictions of wind farm wakes. These choices include vertical resolution, horizontal resolution, and whether or not to include the addition of turbulent kinetic energy generated by the rotating wind turbines. Despite the sensitivity to model configuration, no clear guidance currently exists for these options. Here we compare simulated wind farm wakes produced by varying model configurations with meteorological observations near a land-based wind farm in flat terrain over several diurnal cycles. A WRF configuration comprised of horizontal resolutions of 3 km or 1 km paired with a vertical resolution of 10 m provides the most accurate representation of wind farm wake effects, such as the correct surface warming and elevated wind speed deficit. The inclusion of turbine-generated turbulence is also critical to produce accurate surface warming and should not be omitted.
Interpretation of multi-scale permeability data through an information theory perspective
Authors: Dell'Oca Aronne , Guadagnini Alberto , Riva Monica
Published: June 2020

Abstract. We employ elements of information theory to quantify (i) the information content related to data collected at given measurement scales within the
same porous medium domain and (ii) the relationships among information contents of datasets associated with differing scales. We focus on gas permeability data collected over Berea Sandstone and Topopah Spring Tuff
blocks, considering four measurement scales. We quantify the way information
is shared across these scales through (i) the Shannon entropy of the data
associated with each support scale, (ii) mutual information shared between
data taken at increasing support scales, and (iii) multivariate mutual
information shared within triplets of datasets, each associated with a given
scale. We also assess the level of uniqueness, redundancy and synergy
(rendering, i.e., information partitioning) of information content that the
data associated with the intermediate and largest scales provide with
respect to the information embedded in the data collected at the smallest
support scale in a triplet. Highlights.
Information theory allows characterization of the information content of permeability data related to differing measurement scales. An increase in the measurement scale is associated with quantifiable loss of information about permeability. Redundant, unique and synergetic contributions of information are evaluated for triplets of permeability datasets, each taken at a given scale.
Bilingual Education in Western Canada and Chinese Language Minority Students’ Self Perceptions of their Citizenship and Ethnicity
Authors: Wu Joe
Published: June 2020

Various bilingual education models can either empower or disable minority students according to their goals, structures and human relations (Akkari, 1998). This article presents the findings of a case study on a bilingual program that exists in Western Canada. It examines the structure and contents of the program, and then, based on interviews with a group of Grade 6 bilingual students, discusses their self perceptions of their citizenship, ethnic identity and multicultural thinking.
Selon leurs buts, leurs structures et leurs relation humaines, les modèles d’éducation bilingue peuvent donner plus de pouvoir ou en enlever aux élèves des minorités (Akkari, 1998). Cet article fait état des résultats d’une étude de cas réalisée sur un programme bilingue qui existe dans l’Ouest canadien. Nous examinons la structure et les contenus du programme, et ensuite, en nous basant sur des entrevues avec un groupe d’élèves bilingues de sixième année du primaire, nous mettons en évidence leurs perceptions d’eux-mêmes au regard de leur citoyenneté, de leur identité ethnique et de leur pensée sur le multiculturalisme.
Citizenship Education for Child Citizens
Authors: Howe Brian
Published: June 2020

One important reason for the inadequacy of current citizenship education is that children – defined here as all young persons under age 18 - are rarely seen and treated as citizens in their own right. To the extent that children are educated about citizenship, they typically learn about their rights and responsibilities as future adult citizens. They rarely learn that they are citizens of the present and they are rarely treated as such. This article reviews the modern meaning of citizenship and shows, in reference to the UN Convention on the Rights of the Child, that children indeed are citizens of the present. It shows that when the ingredients of the modern understanding of citizenship are applied to children – rights, responsibilities, participation, and differentiated citizenship – children need to be recognized as citizens. Such an understanding, it is contended, is a necessary foundation for successful citizenship education.
Une cause importante du caractère inadéquat de l’éducation à la citoyenneté actuelle est que les enfants – définis ici comme toutes les personnes de moins de 18 ans – sont rarement vus et traités comme des citoyens à part entière. Dans la mesure où les enfants sont éduqués à propos de la citoyenneté, ils apprennent habituellement des notions sur leurs droits et responsabilités qu’ils auront une fois adultes. Ils apprennent rarement qu’ils sont déjà eux-mêmes des citoyens et qu’ils devraient être traités comme tels. Cet article analyse la signification moderne de la citoyenneté et montre, en se basant sur la Convention des Droits de l’enfant des Nations-Unies, que les enfants sont effectivement des citoyens dans le présent. Ainsi, lorsque les ingrédients de la compréhension moderne de la citoyenneté sont appliqués aux enfants – droits, responsabilités, participation et citoyenneté différenciée –, les enfants doivent être reconnus comme citoyens. L’auteur soutient qu’une telle compréhension est un fondement nécessaire pour la réussite de l’éducation à la citoyenneté.