bluuebunny/crossref_metadata_2025 huggingface dataset:
A Cross-Cultural Exploration of Academic Dishonesty
Authors: Pan Minqi , Stiles Beverly L. , Tempelmeyer Teresa C. , Wong Newman
Published: April 2019

Academic dishonesty (AD) continues to be of great concern in higher education (HE). In this chapter, the authors review literature in this area, with a particular emphasis on preventive interventions. In recent years, with the dramatic increase of international students in HE, the authors also address how cultural diversity may further complicate this issue. A current study of cheating behaviors is discussed comparing a sample of undergraduate college students from the United States (US) with a sample of undergraduate college students from China. With reference to those results, the authors then propose intervention strategies for reducing AD based on the literature and results of this comparative study.
A Critical Analysis
Authors: Butale Chandapiwa , Motswagosele Dineo Phana
Published: April 2019

The University of Botswana (UB) has set high standards for student conduct aimed at maintaining its vision to be a leading center of academic excellence in Africa and the world. The institution pursues excellence by establishing high entrance requirements and strict regulations governing academic conduct. Students are expected to uphold the tenets of excellence through (among others) accountability for their performance and honesty in their pursuit of academic goals. Despite the high standards, cases of academic misconduct still occur. This chapter explores the reasons behind unsanctioned academic behavior by students. Further, the meaning of academic misconduct at the UB and how it is addressed will be discussed. This work will also interrogate the gap between institutional expectations and student behavior to find mutually beneficial ways to attain excellence.
Strategies for Developing Mobile Location-Based Learning Activities by Teachers
Authors: Tal Hagit Meishar
Published: April 2019

This chapter analyses the educational activities created by teachers on an online game generator, Treasure-HIT. The analysis focused on two main components that exist in every game: (1) the location clue, which leads the players to the different stations of the game, and (2) the station task, which the players have to perform when they reach the right station. This qualitative research was based on content analysis of the activities accumulated on the system's server. A total of 112 games were analyzed, including 1272 clues, 1005 stations and 1862 station tasks. Five types of location-dependent tasks were identified: identifying information found on site, camera documentation, receiving an answer from someone on site, physical activities dependent on the location, measurements using a mobile phone, and leaving a personal mark.
Variable Neighborhood Search Algorithm for the Variable Cost and Size Bin Packing Problem
Authors: Fraire-Huacuja Héctor J. , Padilla Alejandro Estrada , Cruz-Reyes Laura , Gómez-Santillán Claudia , Rangel-Valdez Nelson , Morales-Rodríguez María Lucila , Frausto Juan
Published: April 2019

A company that transports goods to supply customers usually needs to plan the routes that the fleet must follow, since transportation means a high percentage of the value added to goods. The vehicles must be loaded with the products located in the warehouse to fulfill the orders requested by customers. Many enterprises use order batching and picking systems to improve the warehouse management. This chapter describes a novel algorithm based on the methodology of variable neighborhood search for the variable cost and size bin packing problem. This problem considers that the sizes and costs of the bins can be different and there is no correlation between them, which is a sensible assumption for the order batching process in many applications. A series of computational experiments were conducted with a set of hard instances to validate this approach. The results show that the proposed algorithm outperforms the state-of-the-art algorithm, and a statistical hypothesis test is used to support the obtained conclusions.
Tri-Objective Optimization Model for Order Picking
Authors: Meza-Barrón Francisco Federico , Rangel-Valdez Nelson , Hernández-Marín Juan Carlos , Morales-Rodríguez María Lucila , Cruz-Reyes Laura
Published: April 2019

Warehousing in profit-oriented environments requires handling complex constraints for planning, organizing, or managing tasks. A large amount of input causes a high degree of complexity, as in the case of the management of customer time windows to accurately deliver them their products. This problem is the well-known order picking problem (OPP) with timetabling constraints, and this chapter proposes a tri-objective optimization model to handle it. The novelty of the approach involves 1) incorporating preferences to search the best compromise of OPP, 2) facing any number of OPP constraints as tri-objective optimization model, and 3) dynamical feedbacking from changes in the state of preferences due to possible interactions with a decision maker. This chapter offers a theoretical analysis of the advantages and disadvantages of the proposed model regarding the new features, which, according to the literature, has not been used so far.
Use of Compensatory Fuzzy Logic for Knowledge Discovery Applied to the Warehouse Order Picking Problem for Real-Time Order Batching
Authors: Cruz-Reyes Laura , Espin-Andrade Rafael Alejandro , Irrarragorri Fernando López , Medina-Trejo César , Tristán José Fernando Padrón , Martinez-Vega Daniel A. , Peralta Carlos Eric Llorente
Published: April 2019

Order picking is an activity in a warehouse, carried out by a team, where customer orders are prepared. It is also the activity with the highest logistic costs in a company. In this chapter, a proposal is presented aimed at improving the order picking process in a warehouse. Order picking continues to attract the attention of people in charge of optimizing processes in a company for minimizing costs. There are several approaches to order picking such as discrete picking, batch picking, and zone picking. The purpose of this study is mainly oriented toward the reduction of batch picking times to achieve an improvement in the service. In this chapter is proposed the application of compensatory fuzzy logic (CFL), which is a branch of classical logic and is also discussed the possibility of making real-time order batches (dynamic batching) by using compensatory fuzzy rules for the classification of incoming orders.
Solving a Floral Order-Picking Model Using a Metaheuristic to Seven Societies of Central Asia
Authors: Ochoa Ortiz-Zezzatti Alberto
Published: April 2019

In several societies of emerging economies, an increasingly large community collects and buys bouquets for celebration purposes linked to the scalability and adjustment of components. Many schools use floral design customization to improve aspects of sociability in schools with problems of structured violence. So, second-hand cargoes of separate parts can build bouquets at a low cost. An order-picking algorithm can be used as the primary guideline because providers often implement a route system depending on the needs for the assembly of the floral design considering the different components that are required and using a model associated with the relevance of a match according to the customization of the new bouquets. In many cases, it has been challenging to develop an adequate transfer of the components; thus, the same routes have been used for a long time, and new provisions on traffic behavior and new routes are not considered. In this research is proposed a new algorithm based on the behavior of birds, called PSO to improve and solve the problem of this order picking model.
Implementing of a Business Model for an Order Picking Related to Agribusiness
Authors: Peralta Jose Jesus Jimenez , Pérez Miguel Ángel García , Ramirez Rene Jimenez Santiago
Published: April 2019

This chapter is focused on the main economic activities in the city of Naranjos Veracruz, which are agriculture and livestock. It is proposed the implementation of an order picking algorithm for the optimization of the packing and distribution of agricultural products, in the Naranjos Veracruz area, by means of an advanced selection of systems, which is fundamental for the operational improvement and logistics global supply chain. In this system, the containers for individual orders travel from one area to another where they are delivered to the picking stations where a worker picks up the carousels. These batch processing stations use specific systems to direct the correct amount to each batch. During this process, the bulk components of the orders can be picked up by the workers in forklifts or another type of cargo vehicle that places an order at once or in batches. All these components meet in consolidation.
An Integrated Methodology for Evaluation of Electric Vehicles Under Sustainable Automotive Environment
Authors: Biswas Tapas Kumar , Stević Željko , Chatterjee Prasenjit , Yazdani Morteza
Published: April 2019

In this chapter, a holistic model based on a newly developed combined compromise solution (CoCoSo) and criteria importance through intercriteria correlation (CRITIC) method for selection of battery-operated electric vehicles (BEVs) has been propounded. A sensitivity analysis has been performed to verify the robustness of the proposed model. Performance of the proposed model has also been compared with some of the popular MCDM methods. It is observed that the model has the competency of precisely ranking the BEV alternatives for the considered case study and can be applied to other sustainability assessment problems.
A Hybrid MCDM Method for Optimization of VAWT Performance Parameters
Authors: Biswas Agnimitra , Jagadish  , Gupta Rajat
Published: April 2019

Vertical axis wind turbines (VAWT) have an inherent limitation of power performance for its low efficiency. However, the design of VAWT can be tailor-made to work in its built environment due to its varied advantages compared to other designs. Thus, the performance optimization problem entails a multitude framework of designs and operating conditions that must be satisfied for harnessing effective wind power from the turbine design. Furthermore, optimization of the performance of VAWT is considered to be an MCDM optimization problem. In this context, the chapter proposes a hybrid MCDM consisting of entropy and VIKOR-based methods for performance parameter optimizations of VAWT. To show the strength and applicability, a real-life case of optimizing performance parameters (Savonius type VAWT [SVAWT]) is used. The results show that SVWAT provides optimal results at an overlap ratio (16%), Vfree (34.763 m/s), N (3796 rpm), V (26.499 m/s), TSR (0.732).
Position Independent Mobile User Authentication Using Keystroke Dynamics
Authors: Saini Baljit Singh , Kaur Navdeep , Bhatia Kamaljit Singh
Published: April 2019

In this chapter, a novel technique to authenticate a mobile phone user irrespective of his/her typing position is presented. The user is never always in sitting position while using mobile phone. Thus, it becomes very important to check the accuracy of keystroke dynamics technique while taking input in all positions but authenticating the user irrespective of these positions. Three user positions were considered for input – sitting, walking, and relaxed. The input was taken in uncontrolled environment to get realistic results. Hold time, latency, and motion features using accelerometer data were extracted, and the analysis was done using random forest and KNN classifiers. The accelerometer data provides additional features like mean of all X, Y, and Z axis values. The inclusion of these features improved the results drastically and played a very significant role in determining the user typing behavior. An EER of 4.3% was achieved with a best FAR of 0.9% and an FRR of 15.2%.
Efficacy of epidural steroid injection in management of lumbar disc lesion
Authors: El-Ghait Hussein A.E.A. , Akar Ahmed I. , Hegazy Abdelazim A. , El-Maadawy Mahmoud A.
Published: April 2019

Background and aim

Low back pain and radiculopathy are the main annoying complaints in patients with degenerative disc diseases. Epidural steroid injection (ESI) has a role to reduce pain and improve disability by decreasing inflammatory process at the nerve root caused by herniated disc. This study was done to evaluate the efficacy of lumbar ESI regarding the improvement of pain and functional outcome.

Patients and methods

This study was a prospective randomized study on 30 patients, aged between 30 and 65 years with low back pain and lumbar radiculopathy secondary to lumbar disc prolapse with no absolute indication for surgery. The patients were treated by lumbar epidural injection of steroids. Patients were divided randomly into two groups: group 1 included 15 patients subjected to lumbar interlaminar ESI, and group 2 included 15 patients subjected to lumbar transforaminal ESI. Patients were evaluated using visual analog scale (VAS) score for pain and the Oswestry Disability Index (ODI) for functional capacity. They were followed up after 4 weeks, and clinical and functional outcomes were assessed using the same tools for evaluation.

Results

The mean VAS for the 30 patients improved by 58.33% (P<0.001), and the mean ODI for the 30 patients improved by 35.4% after 4 weeks following injection (P<0.001). In group 1, the mean VAS improved by 52% and the mean ODI improved by 31.13% after 4 weeks following injection (P<0.001). In group 2, the mean VAS improved by 64.66% and the mean ODI improved by 39.66% after 4 weeks following injection (P<0.001). We found that the mean improvement of VAS and ODI was more in group 2 than in group 1(P<0.026).

Conclusion

We found by the end of the study that the ESI is a safe and effective procedure in alleviating radicular pain and improvement of functional outcome, but the transforaminal approach gives better results than the interlaminar approach.
Mini-Workshop: Arithmetic Geometry and Symmetries around Galois and Fundamental Groups
Authors: Collas Benjamin , Dèbes Pierre , Fried Michael D.
Published: April 2019

The geometric study of the absolute Galois group of the rational numbers has been a highly active research topic since the first milestones: Hilbert’s Irreducibility Theorem, Noether’s program, Riemann’s Existence Theorem. It gained special interest in the last decades with Grothendieck’s “Esquisse d’un programme”, his “Letter to Faltings” and Fried’s introduction of Hurwitz spaces. It grew on and thrived on a wide range of areas, e.g. formal algebraic geometry, Diophantine geometry, group theory. The recent years have seen the development and integration in algebraic geometry and Galois theory of new advanced techniques from algebraic stacks,

\ell

-adic representations and homotopy theories. It was the goal of this mini-workshop, to bring together an international panel of young and senior experts to draw bridges towards these fields of research and to incorporate new methods, techniques and structures in the development of geometric Galois theory.
Mini-Workshop: Superexpanders and Their Coarse Geometry
Authors: Khukhro Ana , de Laat Tim , de la Salle Mikael
Published: April 2019

It is a deep open problem whether all expanders are superexpanders. In fact, it was already a major challenge to prove the mere existence of superexpanders. However, by now, some classes of examples are known: Lafforgue’s expanders constructed as sequences of finite quotients of groups with strong Banach property (T), the examples coming from zigzag products due to Mendel and Naor, and the recent examples coming from group actions on compact manifolds. The methods which are used to construct superexpanders are typically functional analytic in nature, but also rely on arguments from geometry and combinatorics. Another important aspect of the study of superexpanders is their (coarse) geometry, in particular in order to distinguish them from each other.

The aim of this workshop was to bring together researchers working on superexpanders and their coarse geometry from different perspectives, with the aim of sharing expertise and stimulating new research.
Quadratic Forms and Related Structures over Fields
Authors: Becher Karim Johannes , Hoffmann Detlev , Quéguiner-Mathieu Anne
Published: April 2019

The range of topics discussed at the workshop “Quadratic Forms and Related Structures over Fields” included core themes from the algebraic theory of quadratic and hermitian forms and their Witt groups, several aspects of the theory of linear algebraic groups and homogeneous varieties, cohomological invariants as well as some arithmetic aspects pertaining to the theory of quadratic forms over certain types of ground fields, e.g., function fields.
Interactions between Operator Space Theory and Quantum Probability with Applications to Quantum Information
Authors: Franz Uwe , Junge Marius , Pisier Gilles , Xu Quanhua
Published: April 2019

Operator space theory was the joining element of our workshop. This theory is a quantisation of the theory of Banach spaces. The talks at our meeting investigated the interactions of operator space theory with operator algebras and other areas of functional analysis, with classical and quantum probability, with noncommutative harmonic analysis, and, in particular, with quantum information theory.
Cohomological and Metric Properties of Groups of Homeomorphisms of R
Authors: Burillo José , Bux Kai-Uwe , Nucinkis Brita E. A.
Published: April 2019

In recent years, the family of groups sharing features or design principles with classical Thompson groups has grown considerably. The workshop highlights new developments in this field with special emphasis on algorithmic questions, cohomological properties, and smoothability of actions.
Subgroups of Cremona Groups
Authors: Catanese Fabrizio , Cheltsov Ivan , Déserti Julie , Prokhorov Yuri
Published: April 2019

There have been recent breakthroughs in two related questions: the study of Cremona groups, and the problem of rationality of algebraic varieties. Our workshop brought together algebraic geometers, who discussed and tried to solve problems that are relevant to the classification of finite subgroups of Cremona groups. Priority was given to the following four related areas: automorphisms of algebraic varieties, birational geometry of Mori fibre spaces, and rationality problems.
Algebraische Zahlentheorie
Authors: Kings Guido , Sujatha Ramdorai , Urban Eric , Venjakob Otmar
Published: April 2019

The origins of Algebraic Number Theory can be traced to over two centuries ago, wherein algebraic techniques are used to glean information about integers and rational numbers. It continues to be at the forefront of modern research as it evolves to straddle wider areas of Mathematics.
Práticas de governança pública municipal: análise informacional dos sítios eletrônicos em portais de transparência
Authors: Camilo Silvio Parodi Oliveira , Manenti Rosana Vieira Alves , Yamaguchi Cristina Keiko
Published: April 2019

O objetivo geral do presente estudo é identificar práticas de governança pública, por meio da estrutura obrigatória e recomendável nos portais de transparência, na geração de informação à sociedade nos municípios da microrregião de Criciúma–SC, e sugerir proposições de pesquisa. A abordagem é qualitativa, com objetivos descritivos, com emprego do exame de dados informacionais mediante a disposição por e-governo. Os dados levantados sugerem que os gestores dos municípios da amostra não cumprem na íntegra as estipulações obrigatórias estabelecidas na legislação pertinente. Não se pode afirmar que o gestor público transparece sua gestão, por meio do e-governo, à população e aos interessados de modo compreensível e eficiente. Vê-se que os municípios dessa região não adotam boas práticas de governança.
Estudo sobre sombreamento em planta fotovoltaica localizada em zona urbana de Fortaleza-CE
Authors: Chaves Matheus De Paula , Dupont Ivonne Montero , Carvalho Paulo Cesar Marques de , Araujo Danielly Norberto
Published: April 2019

Em decorrência do avanço da implementação de plantas Fotovoltaicas (FV) localizadas em grandes centros, estudos são necessários para analisar os fatores que afetam esta geração de energia elétrica. No presente artigo, uma análise é realizada sobre o impacto do sombreamento em uma planta FV localizada em zona urbana e conectada à rede elétrica do Laboratório de Energias Alternativas (LEA) da UFC, campus Pici, Fortaleza-CE. Antes de cada experimento foi feita a limpeza dos módulos FV de maneira a garantir maior confiabilidade ao estudo. Para análise foram gerados diferentes
padrões de sombreamento, estáticos e dinâmicos, visando simular situações reais de não-idealidades na planta. O sombreamento estático consiste na sombra projetada sobre os módulos que não varia sua posição ao longo do tempo; no sombreamento dinâmico, a sombra varia no decorrer do tempo. Para comparar as variáveis de desempenho da planta FV foram escolhidos dias com médias de irradiância semelhantes durante o período dos experimentos. Calculou-se o Fator de Capacidade (FC) para os quatro experimentos analisados, divididos em duas situações de sombreamento estático e duas de sombreamento dinâmico. Como resultado, obteve-se uma
redução do FC de 2,35% e 1,17% para o primeiro caso e de 0,84% e 1,72% para o segundo. As curvas de potência e irradiância foram observadas: verificou-se que para baixas irradiâncias (inferiores a 500 W/m²) o sombreamento não interferiu de modo significativo na potência gerada. A importância dos diodos by-pass e sua atuação em evitar determinadas células sombreadas de comportarem-se como carga foi explicitada.
Receptor modelling of both particle composition and size distribution from a background site in London, UK – a two-step approach
Authors: Beddows David C. S. , Harrison Roy M.
Published: April 2019

Abstract. Some air pollution datasets contain multiple variables with a
range of measurement units, and combined analysis using positive matrix
factorization (PMF) can be problematic but can offer benefits through the
greater information content. In this work, a novel method is devised and the
source apportionment of a mixed unit dataset (PM10 mass and number size
distribution, NSD) is achieved using a novel two-step approach to PMF. In the
first step the PM10 data are PMF-analysed using a source apportionment
approach in order to provide a solution which best describes the environment
and conditions considered. The time series G values (and errors) of the
PM10 solution are then taken forward into the second step, where they are
combined with the NSD data and analysed in a second PMF analysis. This
results in NSD data associated with the apportioned PM10 factors. We
exemplify this approach using data reported in the study of Beddows et
al. (2015), producing one solution which unifies the two separate solutions
for PM10 and NSD data datasets together. We also show how regression of
the NSD size bins and the G time series can be used to elaborate the solution
by identifying NSD factors (such as nucleation) not influencing the
PM10 mass.
Exploring accumulation-mode H2SO4 versus SO2 stratospheric sulfate geoengineering in a sectional aerosol–chemistry–climate model
Authors: Vattioni Sandro , Weisenstein Debra , Keith David , Feinberg Aryeh , Peter Thomas , Stenke Andrea
Published: April 2019

Abstract. Stratospheric sulfate geoengineering (SSG) could
contribute to avoiding some of the adverse impacts of climate change. We
used the SOCOL-AER global aerosol–chemistry–climate model to investigate 21
different SSG scenarios, each with 1.83 Mt S yr−1 injected either in
the form of accumulation-mode H2SO4 droplets (AM H2SO4),
gas-phase SO2 or as combinations of both. For most scenarios, the
sulfur was continuously emitted at an altitude of 50 hPa (≈20 km) in the
tropics and subtropics. We assumed emissions to be zonally and latitudinally
symmetric around the Equator. The spread of emissions ranged from
3.75∘ S–3.75∘ N to 30∘ S–30∘ N. In
the SO2 emission scenarios, continuous production of tiny nucleation-mode
particles results in increased coagulation, which together with gaseous
H2SO4 condensation, produces coarse-mode particles. These large
particles are less effective for backscattering solar radiation and have a
shorter stratospheric residence time than AM H2SO4 particles. On
average, the stratospheric aerosol burden and corresponding all-sky
shortwave radiative forcing for the AM H2SO4 scenarios are about
37 % larger than for the SO2 scenarios. The simulated stratospheric
aerosol burdens show a weak dependence on the latitudinal spread of
emissions. Emitting at 30∘ N–30∘ S instead of
10∘ N–10∘ S only decreases stratospheric burdens by about 10 %.
This is because a decrease in coagulation and the resulting smaller particle
size is roughly balanced by faster removal through
stratosphere-to-troposphere transport via tropopause folds. Increasing the
injection altitude is also ineffective, although it generates a larger
stratospheric burden, because enhanced condensation and/or coagulation leads
to larger particles, which are less effective scatterers. In the case of
gaseous SO2 emissions, limiting the sulfur injections spatially and
temporally in the form of point and pulsed emissions reduces the total
global annual nucleation, leading to less coagulation and thus smaller
particles with increased stratospheric residence times. Pulse or point
emissions of AM H2SO4 have the opposite effect: they decrease
the stratospheric aerosol burden by increasing coagulation and only slightly
decrease clear-sky radiative forcing. This study shows that direct emission
of AM H2SO4 results in higher radiative forcing for the same
sulfur equivalent mass injection strength than SO2 emissions, and that
the sensitivity to different injection strategies varies for different forms
of injected sulfur.
Compliance and port air quality features with respect to ship fuel switching regulation: a field observation campaign, SEISO-Bohai
Authors: Zhang Yanni , Deng Fanyuan , Man Hanyang , Fu Mingliang , Lv Zhaofeng , Xiao Qian , Jin Xinxin , Liu Shuai , He Kebin , Liu Huan
Published: April 2019

Abstract. Since 1 January 2017, ships berthed at the core ports of three designated “domestic emission control
areas” (DECAs) in China should be using fuel with a sulfur content less than
or equal to 0.5 %. In order to evaluate the impacts of fuel switching, a
measurement campaign (SEISO-Bohai) was conducted from 28 December 2016 to
15 January 2017 at Jingtang Harbor, an area within the seventh busiest port
in the world. This campaign included meteorological monitoring, pollutant
monitoring, aerosol sampling and fuel sampling. During the campaign, 16 ship
plumes were captured by the on-shore measurement site, and 4 plumes indicated
the usage of high-SF (SF refers to the sulfur content of marine fuels).
The average reduction of the mean ΔNOx∕ΔSO2 ratio from high-sulfur
plumes (3.26) before 1 January to low-sulfur plumes (12.97) after 1 January
shows a direct SO2 emission reduction of 75 %, consistent with
the sulfur content reduction (79 %). The average concentrations of
PM2.5 (particulate matter with a diameter less than 2.5 µm),
NOx, SO2, O3 and CO during
campaign were 147.85 µg m−3,
146.93, 21.91, 29.68 ppb and 2.21 ppm, respectively, among
which NOx reached a maximum hourly concentration of 692.6 ppb, and
SO2 reached a maximum hourly concentration of 165.5 ppb.
The mean concentrations of carbonaceous and dominant ionic
species in particles were 6.52 (EC – elemental carbon), 23.10 (OC – organic carbon), 22.04 (SO42-), 25.95
(NO3-) and 13.55 (NH4+) µg m−3.
Although the carbonaceous species in particles were not significantly
affected by fuel switching, the gas and particle pollutants in the ambient air
exhibited clear and effective improvements due to the implementation of low-sulfur
fuel. Comparison with the prevailing atmospheric conditions and a wind map of
SO2 variation concluded a prompt SO2 reduction of 70 % in
ambient air after fuel switching. Given the high humidity at the study site, this
SO2 reduction will abate the concentration of secondary aerosols and improve
the acidity of particulate matter. Based on the enrichment factors of elements in
PM2.5, vanadium was identified as a marker of residual fuel ship
emissions, decreasing significantly by 97.1 % from 309.9 ng m−3 before fuel switching to 9.1 ng m−3 after regulation, which
indicated a crucial improvement due to the implementation of low-sulfur
fuels. Ship emissions were proven to be significantly influential both
directly and indirectly on the port environment and the coastal areas around Bohai
Bay, where the population density reaches over 650 people per square kilometer. The
results from this study report the positive impact of fuel
switching on the air quality in the study region and indicate
a new method for identifying the ship fuel type used by vessels in the area.
Remote biomass burning dominates southern West African air pollution during the monsoon
Authors: Haslett Sophie L. , Taylor Jonathan W. , Evans Mathew , Morris Eleanor , Vogel Bernhard , Dajuma Alima , Brito Joel , Batenburg Anneke M. , Borrmann Stephan , Schneider Johannes , Schulz Christiane , Denjean Cyrielle , Bourrianne Thierry , Knippertz Peter , Dupuy Régis , Schwarzenböck Alfons , Sauer Daniel , Flamant Cyrille , Dorsey James , Crawford Ian , Coe Hugh
Published: April 2019

Abstract. Vast quantities of agricultural land in southern and central Africa are burnt between June and September each year, which releases large concentrations of aerosols into the atmosphere. The resulting smoke plumes are carried west over the Atlantic Ocean at altitudes between 2 and 4 km. As only limited observational data in West Africa have existed until now, whether this pollution has an impact at lower altitudes has remained unclear. The Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) aircraft campaign took place in southern West Africa during June and July 2016, with the aim of observing gas and aerosol properties in the region in order to assess anthropogenic and other influences on the atmosphere. Results presented here show that a significant mass of aged accumulation mode aerosol was present in the southern West African boundary layer, over both the ocean and the continent. A median dry aerosol concentration of 6.2 µg m−3 (standard temperature and pressure (STP)) was observed over the Atlantic Ocean upwind of the major cities, with an interquartile range from 5.3 to 8.0 µg m−3. This concentration increased to a median of 11.1 µg m−3 (8.6 to 15.7 µg m−3) in the immediate outflow from cities. In the continental air mass away from the cities, the median aerosol loading was 7.5 µg m−3, with an interquartile range of 4.2 µg m−3. The accumulation mode aerosol population over land displayed similar chemical properties to the upstream population, which implies that upstream aerosol is a significant source of aerosol pollution over the continent. The upstream aerosol is found to have most likely originated from central and southern African biomass burning. This demonstrates that biomass burning plumes are being advected northwards, after being entrained into the monsoon layer over the eastern tropical Atlantic Ocean. It is shown observationally for the first time that they contribute up to 80 % to the regional aerosol loading in the boundary layer of southern West Africa during the monsoon season. As a result, the large and growing emissions from the coastal cities are overlaid on an already substantial aerosol background. On a regional scale this renders cloud properties and precipitation less sensitive to future increases in anthropogenic emissions. Such high background loadings will lead to greater pollution exposure for the large and growing population in southern West Africa. These results emphasise the importance of including aerosol from across country borders in the development of air pollution policies and interventions in regions such as West Africa.
A low-cost monitor for measurement of fine particulate matter and aerosol optical depth – Part 2: Citizen science pilot campaign in northern Colorado
Authors: Ford Bonne , Pierce Jeffrey R. , Wendt Eric , Long Marilee , Jathar Shantanu , Mehaffy John , Tryner Jessica , Quinn Casey , van Zyl Lizette , L'Orange Christian , Miller-Lionberg Daniel , Volckens John
Published: April 2019

Abstract. A pilot field campaign was conducted in the fall and winter of 2017 in northern Colorado to test the deployment of the Aerosol Mass and Optical Depth (AMOD) instrument as part of the Citizen-Enabled Aerosol Measurements for Satellites (CEAMS) network. Citizen scientists were recruited to set up the device to take filter and optical measurements of aerosols in their backyards. The goal of the network is to provide more surface particulate matter and aerosol optical depth (AOD) measurements to increase the spatial and temporal resolution of PM2.5 to AOD ratios and to improve satellite-based estimates of air quality. Participants collected 65 filters and 160 multi-wavelength AOD measurements from which 109 successful PM2.5 to AOD ratios were calculated. We show that PM2.5, AOD, and their ratio (PM2.5:AOD) often vary substantially over relatively short spatial scales; this spatial variation is not typically resolved by satellite- and model-based PM2.5 exposure estimates. The success of the pilot campaign suggests that citizen-science networks are a viable means for providing new insight into surface air quality. We also discuss lessons learned and AMOD design modifications, which will be used in future, wider deployments of the CEAMS network.
A low-cost monitor for measurement of fine particulate matter and aerosol optical depth. Part 1: Specifications and testing
Authors: Wendt Eric A. , Quinn Casey W. , Miller-Lionberg Daniel D. , Tryner Jessica , L'Orange Christian , Ford Bonne , Yalin Azer P. , Pierce Jeffrey R. , Jathar Shantanu , Volckens John
Published: April 2019

Abstract. Globally, fine particulate matter (PM2.5) air pollution is a leading contributor to death, disease, and environmental degradation. Satellite-based measurements of aerosol optical depth (AOD) are used to estimate PM2.5 concentrations across the world, but the relationship between satellite-estimated AOD and ground-level PM2.5 is uncertain. Sun photometers measure AOD from the Earth's surface and are often used to improve satellite data; however, reference-grade photometers and PM2.5 monitors are expensive and rarely co-located. This work presents the development and validation of the Aerosol Mass and Optical Depth (AMOD) sampler, an inexpensive and compact device that simultaneously measures PM2.5 mass and AOD and was designed specifically to be used in citizen science campaigns. The AMOD utilizes a low-cost light-scattering sensor in combination with a gravimetric filter measurement to quantify ground-level PM2.5. Aerosol optical depth is measured using optically filtered photodiodes at four discrete wavelengths. Field validation studies revealed agreement within 10 % for AOD values measured between co-located AMOD and AErosol RObotics NETwork (AERONET) monitors and for PM2.5 mass measured between co-located AMOD and EPA Federal Equivalent Method (FEM) monitors. These results demonstrate that the AMOD can quantify AOD and PM2.5 accurately at a fraction of the cost of existing reference monitors.
Atmospheric deposition fluxes over the Atlantic Ocean: a GEOTRACES case study
Authors: Menzel Barraqueta Jan-Lukas , Klar Jessica K. , Gledhill Martha , Schlosser Christian , Shelley Rachel , Planquette Hélène F. , Wenzel Bernhard , Sarthou Geraldine , Achterberg Eric P.
Published: April 2019

Abstract. Atmospheric deposition is an important source of micronutrients to the
ocean, but atmospheric deposition fluxes remain poorly constrained in most
ocean regions due to the limited number of field observations of wet and dry
atmospheric inputs. Here we present the distribution of dissolved aluminium
(dAl), as a tracer of atmospheric inputs, in surface waters of the Atlantic
Ocean along GEOTRACES sections GA01, GA06, GA08, and GA10. We used the
surface mixed-layer concentrations of dAl to calculate atmospheric
deposition fluxes using a simple steady state model. We have optimized the
Al fractional aerosol solubility, the dAl residence time within the surface
mixed layer and the depth of the surface mixed layer for each separate cruise to
calculate the atmospheric deposition fluxes. We calculated the lowest
deposition fluxes of 0.15±0.1 and 0.27±0.13 g m−2 yr−1
for the South and North Atlantic Ocean (>40∘ S and >40∘ N) respectively, and the highest fluxes of 1.8
and 3.09 g m−2 yr−1 for the south-east Atlantic and tropical
Atlantic Ocean, respectively. Overall, our estimations are comparable to
atmospheric dust deposition model estimates and reported field-based
atmospheric deposition estimates. We note that our estimates diverge from
atmospheric dust deposition model flux estimates in regions influenced by
riverine Al inputs and in upwelling regions. As dAl is a key trace element
in the GEOTRACES programme, the approach presented in this study allows
calculations of atmospheric deposition fluxes at high spatial resolution for
remote ocean regions.
Partitioning net ecosystem exchange of CO2 on the pedon scale in the Lena River Delta, Siberia
Authors: Eckhardt Tim , Knoblauch Christian , Kutzbach Lars , Holl David , Simpson Gillian , Abakumov Evgeny , Pfeiffer Eva-Maria
Published: April 2019

Abstract. Arctic tundra ecosystems are currently facing amplified rates of climate
warming. Since these ecosystems store significant amounts of soil organic
carbon, which can be mineralized to carbon dioxide (CO2) and methane
(CH4), rising temperatures may cause increasing greenhouse gas fluxes
to the atmosphere. To understand how net the ecosystem exchange (NEE) of
CO2 will respond to changing climatic and environmental conditions,
it is necessary to understand the individual responses of the processes
contributing to NEE. Therefore, this study aimed to partition NEE at the
soil–plant–atmosphere interface in an arctic tundra ecosystem and to
identify the main environmental drivers of these fluxes. NEE was partitioned
into gross primary productivity (GPP) and ecosystem respiration
(Reco) and further into autotrophic (RA) and
heterotrophic respiration (RH). The study examined CO2 flux
data collected during the growing season in 2015 using closed-chamber
measurements in a polygonal tundra landscape in the Lena River Delta,
northeastern Siberia. To capture the influence of soil hydrology on
CO2 fluxes, measurements were conducted at a water-saturated polygon
center and a well-drained polygon rim. These chamber-measured fluxes were
used to model NEE, GPP, Reco, RH, RA, and net
primary production (NPP) at the pedon scale (1–10 m) and to determine
cumulative growing season fluxes. Here, the response of in situ measured
RA and RH fluxes from permafrost-affected soils of the
polygonal tundra to hydrological conditions have been examined. Although
changes in the water table depth at the polygon center sites did not affect
CO2 fluxes from RH, rising water tables were linked to
reduced CO2 fluxes from RA. Furthermore, this work found
the polygonal tundra in the Lena River Delta to be a net sink for atmospheric
CO2 during the growing season. The NEE at the wet, depressed polygon
center was more than twice that at the drier polygon rim. These differences
between the two sites were caused by higher GPP fluxes due to a higher
vascular plant density and lower Reco fluxes due to oxygen
limitation under water-saturated conditions at the polygon center in
comparison to the rim. Hence, soil hydrological conditions were one of the
key drivers for the different CO2 fluxes across this highly
heterogeneous tundra landscape.
Archaeological prospections in the Roman vicus Belginum (Rhineland-Palatinate, Germany)
Authors: Teegen Wolf-Rüdiger , Cordie Rosemarie , Over Philomena , Mägdefessel Simon , Retzlaff Rebecca , Stoffels Johannes
Published: April 2019

Abstract. The Roman vicus Belginum and the associated Celtic–Roman cemetery have been the subject of systematic archaeological research since 1954. Since 2004, archaeological prospections have been carried out in and around Belginum. Participants included students from the universities of Leipzig, Trier, and Munich as part of study-accompanying field work. This paper deals with the prospections of 2004 and 2016, when nearly 2 ha of land south of the federal road B327 (Hunsrückhöhenstraße) were surveyed. The study area is located on a NW-to-SE-running hillside. All non-local objects present on the surface were collected and three-dimensionally recorded. Previously in 2013, the area was geomagnetically prospected by Posselt & Zickgraf (Marburg). Both surveys revealed a hitherto unknown extent of the vicus about 200 m to the southwest. The findings date back to the late first to third centuries common era. All finds (ceramic, bricks, roof slate, glass, and metal) were recorded and analysed in a QGIS and ArcGIS environment together with lidar scans, the geomagnetic data, and other geographical information. The overall distributions of bricks and pottery were studied in detail. The distribution of bricks is in particular connected to the individual plots, while the pottery is mainly concentrated in the backyards. Regarding surveys in other Roman vici, the brick distribution could be a helpful indicator to identify plots, when no geophysical information is available.
Implementation of the sectional aerosol module SALSA2.0 into the PALM model system 6.0: model development and first evaluation
Authors: Kurppa Mona , Hellsten Antti , Roldin Pontus , Kokkola Harri , Tonttila Juha , Auvinen Mikko , Kent Christoph , Kumar Prashant , Maronga Björn , Järvi Leena
Published: April 2019

Abstract. Urban pedestrian-level
air quality is a result of an interplay between turbulent dispersion
conditions, background concentrations, and heterogeneous local emissions of
air pollutants and their transformation processes. Still, the complexity of
these interactions cannot be resolved by the commonly used air quality
models. By embedding the sectional aerosol module SALSA2.0 into the
large-eddy simulation model PALM, a novel, high-resolution, urban aerosol
modelling framework has been developed. The first model evaluation study on
the vertical variation of aerosol number concentration and size distribution
in a simple street canyon without vegetation in Cambridge, UK, shows good
agreement with measurements, with simulated values mainly within a factor of
2 of observations. Dispersion conditions and local emissions govern the
pedestrian-level aerosol number concentrations. Out of different aerosol
processes, dry deposition is shown to decrease the total number concentration
by over 20 %, while condensation and dissolutional increase the total
mass by over 10 %. Following the model development, the application of
PALM can be extended to local- and neighbourhood-scale air pollution and
aerosol studies that require a detailed solution of the ambient flow field.
The Land Variational Ensemble Data Assimilation fRamework: LaVEnDAR
Authors: Pinnington Ewan , Quaife Tristan , Lawless Amos , Williams Karina , Arkebauer Tim , Scoby Dave
Published: April 2019

Abstract. The Land Variational Ensemble Data Assimilation fRamework (LaVEnDAR) implements the method of Four-Dimensional Ensemble Variational data assimilation for land surface models. Four-Dimensional Ensemble Variational data assimilation negates the often costly calculation of a model adjoint required by traditional variational techniques (such as 4DVar) for optimising parameters/state variables over a time window of observations. In this paper we implement LaVEnDAR with the JULES land surface model. We show the system can recover seven parameters controlling crop behaviour in a set of twin experiments. We run the same experiments at the Mead continuous maize FLUXNET site in Nebraska, USA to show the technique working with real data. We find that the system accurately captures observations of leaf area index, canopy height and gross primary productivity after assimilation and improves posterior estimates of the amount of harvestable material from the maize crop by 74 %. LaVEnDAR requires no modification to the model that it is being used with and is hence able to keep up to date with model releases more easily than other data assimilation methods.
Seasonal drought prediction for semiarid northeast Brazil: what is the added value of a process-based hydrological model?
Authors: Pilz Tobias , Delgado José Miguel , Voss Sebastian , Vormoor Klaus , Francke Till , Costa Alexandre Cunha , Martins Eduardo , Bronstert Axel
Published: April 2019

Abstract. The semiarid northeast of Brazil is one of the most densely populated dryland
regions in the world and recurrently affected by severe droughts. Thus,
reliable seasonal forecasts of streamflow and reservoir storage are of high
value for water managers. Such forecasts can be generated by applying either
hydrological models representing underlying processes or statistical
relationships exploiting correlations among meteorological and hydrological
variables. This work evaluates and compares the performances of seasonal
reservoir storage forecasts derived by a process-based hydrological model and
a statistical approach. Driven by observations, both models achieve similar simulation accuracies. In
a hindcast experiment, however, the accuracy of estimating regional reservoir
storages was considerably lower using the process-based hydrological model,
whereas the resolution and reliability of drought event predictions were
similar by both approaches. Further investigations regarding the deficiencies
of the process-based model revealed a significant influence of antecedent
wetness conditions and a higher sensitivity of model prediction performance
to rainfall forecast quality. Within the scope of this study, the statistical model proved to be the more
straightforward approach for predictions of reservoir level and drought
events at regionally and monthly aggregated scales. However, for forecasts at
finer scales of space and time or for the investigation of underlying
processes, the costly initialisation and application of a process-based model
can be worthwhile. Furthermore, the application of innovative data products,
such as remote sensing data, and operational model correction methods, like
data assimilation, may allow for an enhanced exploitation of the advanced
capabilities of process-based hydrological models.
How do we see fractures? Quantifying subjective bias in fracture data collection
Authors: Andrews Billy J. , Roberts Jennifer J. , Shipton Zoe K. , Bigi Sabina , Tartarello M. Chiara , Johnson Gareth
Published: April 2019

Abstract. The characterisation of natural fracture networks using
outcrop analogues is important in understanding subsurface fluid flow and
rock mass characteristics in fractured lithologies. It is well known from
decision sciences that subjective bias can significantly impact the way data
are gathered and interpreted, introducing scientific uncertainty. This study
investigates the scale and nature of subjective bias on fracture data
collected using four commonly applied approaches (linear scanlines, circular
scanlines, topology sampling, and window sampling) both in the field and in
workshops using field photographs. We demonstrate that geologists' own
subjective biases influence the data they collect, and, as a result,
different participants collect different fracture data from the same
scanline or sample area. As a result, the fracture statistics that are
derived from field data can vary considerably for the same scanline,
depending on which geologist collected the data. Additionally, the personal
bias of geologists collecting the data affects the scanline size (minimum
length of linear scanlines, radius of circular scanlines, or area of a window
sample) needed to collect a statistically representative amount of data.
Fracture statistics derived from field data are often input into geological
models that are used for a range of applications, from understanding fluid
flow to characterising rock strength. We suggest protocols to recognise,
understand, and limit the effect of subjective bias on fracture data biases
during data collection. Our work shows the capacity for cognitive biases to
introduce uncertainty into observation-based data and has implications well
beyond the geosciences.