bluuebunny/crossref_metadata_2025 huggingface dataset:
As Concepções de Professores de Outras Disciplinas sobre o Ensino e a Aprendizagem de Matemática
Authors: Suleiman Amal Rahif
Published: August 2020

Neste texto, investigamos as concepções de professores das disciplinas do currículo da Educação Básica, exceto Matemática. Objetivamos refletir sobre as concepções desses professores quanto ao ensino e aprendizagem da Matemática e sua relação com as demais disciplinas. Visamos, também, fornecer subsídios para Educação Matemática, projetando mudanças na prática docente, mediante o olhar do Outro, podendo minorar as dificuldades e melhorar o rendimento escolar. Nossos resultados apontam que os docentes detêm uma visão utilitarista da Matemática, concebendo-a, de modo geral, como ferramenta auxiliar em suas respectivas disciplinas bem como na vida futura dos alunos. Ademais, esses docentes consideram importante o trabalho interdisciplinar e por áreas, embora reconheçam haver grandes dificuldades na realização desse empreendimento. A pesquisa contribui, portanto, para refletir que, embora a Matemática tenha papel altamente significativo nas aplicações práticas do desenvolvimento atual, possui forma e conteúdo construídos pelo raciocínio, no campo mental, e esse caráter não pode ser negligenciado.
Formulação de Problemas no Eixo de Produto de Medidas: uma proposta para o ensino de multiplicação e divisão no campo conceitual multiplicativo
Authors: Oliveira Altoé Renan , De Oliveira Freitas Rony Cláudio
Published: August 2020

Neste artigo, analisamos o potencial educativo de uma proposta de Formulação de Problemas, intitulada “Um dever de casa desafiador”, desenvolvida para discutir multiplicação e divisão no eixo de Produto de Medidas, em especial, na classe de Configuração Retangular. Seguindo as fases da Engenharia Didática como metodologia de pesquisa, de natureza experimental, elaboramos a atividade em parceria com a professora regente de um 5º ano, de uma escola do Município de Vargem Alta - ES, cuja aplicação envolveu os estudantes em investigação e formulação de seus próprios problemas de matemática. Os resultados revelaram que a proposta é potencialmente interessante para o ensino das operações aritméticas abordadas e, principalmente, fortalecem a Formulação de Problemas como uma importante estratégia pedagógica para o ensino de matemática.
Educação Matemática e Currículo Escolar: um estudo da matemática praticada no ensino técnico agrícola
Authors: Toledo Neila
Published: August 2020

Este artigo tem como objetivo discutir a educação matemática praticada na disciplina de matemática e suas articulações com o dispositivo da tecnocientificidade no curso Técnico em Agropecuária do Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul Campus Sertão (IFRS-Sertão). Os aportes teóricos que lhe dão sustentação encontram-se, principalmente, nas formulações de Michel Foucault e seus comentadores. O material de pesquisa é composto por entrevistas realizadas com recém-formados do IFRS-Sertão, bem como documentos institucionais – projeto pedagógico atual – e materiais escolares desses estudantes. O exercício analítico sobre esse material (realizado na perspectiva da análise do discurso foucaultiano e por meio da abordagem de Storytelling) possibilitou concluir que: a) na atualidade o princípio pedagógico que conduz o currículo da formação do Técnico Agrícola no IFRS-Sertão é o “aprender pela pesquisa’; b) o discurso da educação matemática que opera, na atualidade, no curso Técnico em Agropecuária do IFRS-Sertão pode ser considerado como um dos vetores (mas não o único) que constituem o dispositivo da tecnocientificidade.
Dificuldades de Aprendizagem em Matemática: percepções de professores do Ensino Médio de uma escola estadual do Rio Grande do Sul
Authors: Kuhn Malcus Cassiano
Published: August 2020

O artigo apresenta reflexões sobre dificuldades de aprendizagem em Matemática a partir de percepções de professores do Ensino Médio de uma escola estadual do Rio Grande do Sul. Trata-se de uma pesquisa quanti-qualitativa, com aproximações de um estudo de caso. A partir de um estudo bibliográfico sobre Teoria da Aprendizagem Significativa, ensino da Matemática e aspectos históricos das dificuldades de aprendizagem em Matemática e de uma pesquisa de campo com cinco professores do Ensino Médio, procuram-se identificar causas das dificuldades de aprendizagem em Matemática. As dificuldades estão relacionadas a fatores intra e extra-escolares, tais como: falta de interesse dos estudantes para aprender; falta de conhecimentos básicos de conteúdos desenvolvidos no Ensino Fundamental e metodologia de ensino. Para mudar tal situação, sugere-se: reorganização curricular, valorizando a postura ativa do estudante e o desenvolvimento de habilidades e competências; dinamização de estratégias de ensino; inovação de recursos didáticos; ressignificação do processo avaliativo.
Conhecimento matemático na Educação Infantil: saberes e práticas de professoras num grupo colaborativo
Authors: Stehling Denise França , Conti Keli Cristina
Published: August 2020

O presente artigo traz excertos de uma dissertação, que buscou investigar quais os saberes e conhecimentos matemáticos e metodológicos são mobilizados, reconhecidos e ressignificados por professores da Educação Infantil, da Rede Municipal de Ensino de Belo Horizonte/MG, quando se reúnem em grupo de estudos. Temos como objetivo no artigo apresentar reflexões sobre o conhecimento matemático que deve ser abordado na Educação Infantil, pelo professor e trazer os registros das práticas envolvendo as medidas de tempo e de comprimento, que foram discutidas ao longo de encontros do grupo, destacando os fazeres práticos dos professores. A pesquisa foi desenvolvida partindo de uma abordagem qualitativa e com a perspectiva de elaboração de narrativas orais e escritas. O plano de trabalho de campo e os instrumentos de registros de informações compreenderam a formação do grupo de professoras, aplicação de questionários em alguns momentos, encontros periódicos de formação, discussão, planejamento e registro. Ainda envolveu a elaboração de um diário de campo pela pesquisadora, elaboração de registros pelos participantes, registros de áudio e vídeo das atividades desenvolvidas no grupo e, incentivo à produção de relatos a serem compartilhados com outros professores. Analisamos que os saberes e conhecimentos matemáticos e metodológicos foram mobilizados, e outras aprendizagens como conhecimento curricular, durante a constituição e continuidade do grupo de estudos. Como produto final organizamos, a partir dos encontros e relatos orais e escritos das professoras, um livro, com a perspectiva de constituir um material de viés formativo.
MODELAGEM MATEMÁTICA E FILOSOFIA DA LINGUAGEM: ALGUMAS ARTICULAÇÕES
Authors: Caldeira Ademir Donizeti , Costa Daniana De , Cambi Betina
Published: August 2020

O objetivo deste artigo é realizar um estudo sobre como alguns termos que pertencem ao âmbito da Modelagem Matemática estão sendo pautados no pensamento de Ludwig Wittgenstein. A metodologia baseia-se na pesquisa bibliográfica e o material de análise é constituído por oito artigos científicos que foram publicados em congressos e em periódicos. Pelo estudo realizado, evidenciaram-se termos da Modelagem, tais como: matemática, realidade, modelo, matematização e inteiração, os quais apresentaram um entrelaçamento discursivo com a filosofia da linguagem de Wittgenstein. Constatou-se que tal entrelaçamento ocorre por meio da atividade, ou seja, “ao modelar” é possível detectar como os modeladores articulam tais termos e como os percebem.
PENDIDIKAN AGAMA KRISTEN DALAM MATIUS 28:19-20
Authors: Belo Yosia
Published: August 2020

Abstract: This article talks about a biblical study of the text of Matthew 28: 19-20. This study was conducted to gain an understanding of Christian Religious Education in Matthew 28: 19-20. So that every PAK teacher can apply in applying and teaching students.

Abstrak: Artikel ini berbicara tentang kajian biblika terhadap teks Matius 28:19-20. Kajian ini dilakukan untuk mendapatkan pemahaman tentang Pendidikan Agama Kristen dalam Matius 28:19-20. Supaya dapat diterapkan oleh setiap guru PAK dalam menerapkan dan melakukan pengajaran terhadap peserta didik.
La responsabilidad civil por contingencias laborales
Authors: Arévalo Vela Javier
Published: August 2020

En el presente artículo se efectúa un estudio, desde la legislación, doctrina y jurisprudencia, acerca de la responsabilidad civil del empleador por contingencias laborales, entendidas estas como accidentes de trabajo y enfermedades profesionales. Así, se repasarán algunos conceptos básicos sobre el tema, y se analizará la naturaleza de esta figura, que se ha presentado siempre compleja, en vista de que aún no hallamos consenso ni uniformidad en la norma ni en los autores.
Procedimiento para admitir y actuar pruebas extemporáneas en el proceso laboral peruano
Authors: Chávez Paucar Juan Carlos
Published: August 2020

El presente artículo aborda la problemática del ofrecimiento extemporáneo de medios probatorios en el proceso laboral, formulado en la audiencia de juzgamiento o con posterioridad a ella, o después de emitida la sentencia de primera instancia. Desarrolla los principios y fundamentos, los supuestos, requisitos y presupuestos de procedencia de este proceso. El propósito de este trabajo consiste en perfilar un procedimiento uniforme para el trámite de la admisión y actuación de medios probatorios extemporáneos, y ha sido elaborado desde una óptica eminentemente práctica y sustentada en la experiencia adquirida en el diario quehacer judicial como magistrado.
The Influence of Locally Generated Revenue, Public Allocation Funds and Specific To Financial Performance of The Region in The City/Regency Government in Aceh Province
Authors: Putra Zainal
Published: August 2020

The purpose of this research are: (1). To know how the condition of region own source revenue, the general allocation fund, special allocation fund and regional financial performance , (2). To find out the influence of region own source revenue, the general allocation fund, special allocation fund to the region financial performance, (3). To know the influence of region own source revenue to the region financial performance, (4). To find out the influence of the general allocation fund to the region financial performance, (5). to know the effect of the special allocation fund toward region financial performance. The data used in this research is a secondary data obtained from the office of BPK RI Aceh province Representative. The data collected in the form of pooling data in period of 2008-2012. The entire population in this research are sampled as many as 23 regencies / cities in Aceh province. In analyzing the data using multiple linear regression models. The results showed that: (1). Regencies / cities in Aceh province the category of of region finance ability is “very less" and the category of Region Finance Independence is "very low" with a pattern of "instructive" relationship, (2). The financial performance of the region show a decreasing trend in the span of 2008-2012 , (3). The variable of region own source revenue, general allocation fund, special allocation fund simultaneously influential and significant to the variable of regional financial performance , (4). Partially only variable of general allocation fund and variable of special allocation fund that influence and significant toward the variable of regional financial performance, whereas the variable of region own source revenue does not influence significantly to the variable of regional financial performance.

JEL Classification: H20, H50, P50
Key words: The General Allocation Fund, The Region Own Source Revenue, The Regional Financial Performance, The Special Allocation Fund
The Influence of The Interest Rate (BI Rate) and Non Performing Loan (NPL) To The Distribution of Banking Credit in Bengkulu Province in The Years 2013-2015
Authors: Damarsiwi Eska Prima Monique
Published: August 2020

Banks collect funds from the public in the form of deposits and are distributed back in the form of credit to companies and individuals. This study is aimed to determine the effect of the BI Rate and Non-Performing Loans (NPL) to the capital loan in Bengkulu province in the years 2013-2015. Before doing the multiple regression analysis, the data should be free from the classical assumption.The empiricalresults of this partial analysis show that the variable BI Rate istcount(2.402) >ttable (2,228),this meansthat the BI Rate has a positive effect on bank lending in the province of Bengkulu. Variable Non perfoming loans (NPL) aretcount (2.531)>ttable (2,228) and sig. (0,037) < alpha (0.05), the variable Non-Performing Loan (NPL) revealed a positive and significant effect on bank lending in the province of Bengkulu. Simultaneously the variable BI Rate and Non-Performing Loans (NPL) have the values of F (11.336)> F table (4.96) with sig (0.003) <α (0.05), it means that the variable BI Rate and Non-Performing Loan (NPL) simultaneously / concurrently affect the dependent variable. The result also shows the ability of a model prediction of65.3% while the remaining34.7% are influenced by other factors outside the model that has not been incluioded in the study. Meanwhile the most dominant variable in the study is the variable BI Rate which has a value of the partial coefficient of 62.5%.

JEL Classification: E43, E52, E58
Keywords: BI Rate, Capital Loan, Non-Performing Loans
IMPACT OF EDUCATION TO HEAD OF HOUSEHOLD IN INDONESIA
Authors: Prabowo Maudytia Rismalasari , Priyarsono Dominicus Savio , Probokawuryan Mutiara
Published: August 2020

Poverty is one of the most crucial problems in Indonesia which is the fifth city in South-East Asia, have a poverty line around 11.2% in 2014 (BPS 2016). Moreover, poverty in Indonesia has decreased slowly from 2000 (19.1%) until 2016 (10.9%) (Smeru, 2015). It means poverty in Indonesia should be accelerated the decline. One of the things that can reduce poverty is education (Gounder and Xing 2012). Education has a relationship with household consumption per capita. That means, the higher the education of household head, the higher the consumption per capita that household get. The aim of this study is to analyze the impact of education on poverty as measured by household's consumption in West Indonesia in 2014. This study uses Two-Stage Least Square (2SLS) methods with cross-section data and obtained from IFLS (Indonesia Family Life Survey). The result shows that there is a relationship between education and other independent variables on poverty. The independent variables that significantly affect poverty are age, age squared, gender, and marital status. The implication of this study is education can increase the number of consumption per capita so that the living standard will increase and poverty will decrease.

JEL Classification: I20, I21, I25

Keywords: consumption per capita, cross section, education, Two Stage Least Square, poverty.
THE IMPACT OF MIGRATION ON THE WAGE DISTRIBUTION IN INDONESIA
Authors: Pravitasari Clalisca , Damayanti Arie
Published: August 2020

Research on the impact of migration on workers' wages in destination areas has long been debated in the literature. However, studies that link migration to wage rates in different percentiles along the distribution have not been widely implemented, as migration does not have the same impact on wage levels in all groups of workers. By establishing a counterfactual using the semi-parametric DFL method of National Labor Force Survey data, this study found that migration promotes changes in the distribution of wages, especially in the upper and lower percentiles. After controlling the magnitude of in-migration in each percentile group by using the ordinary least square method, this study also proves that migration leads to wage decreasing in percentile groups where migrant workers are overrepresented, which is in the 75th and 90th percentile groups. Meanwhile, no negative impacts were found on wage levels in the lower middle percentile. In fact, migration has proven to encourage an increase in the average wage of workers in the lowest percentile of the distribution.

JEL Classification: J01, J11, J61
Keywords: counterfactual, migration, wage distribution
THE EFFECT OF NON PERFORMING FINANCING, FINANCING TO DEPOSIT RATIO AND OPERATING EXPENSE TO OPERATING INCOME RATIO (BOPO) TO PROFITABILITY
Authors: Suartini Sri , Sulistiyo Hari , Indrianti Wahyuni
Published: August 2020

The issues raised in this study are: to determine, explain and analyze profitability, Non Perfroming Loan, Financing to Deposit Ratio and Operating Expense to Operating Income in Bank of sharia and the partial effect and simultaneous of NPF, FDR and Operating Expense to Operating Income ratio  to Profitability Bank of sharia Period 2014 -2016.

The number of samples taken 12 Bank of sharia in the study period with saturated sampling technique. This research expected to contribute and to the development of the field of accounting, especially financial accounting. The research methods used by the author in this study, using descriptive and verification, the results showed conclusions are: NPF has no effect on profitability because of the results of calculations performed tcount smaller than ttabel. FDR has not effect on profitability because of the results of calculations performed tcount smaller than ttabel. Partially Operating Expense to Operating Income has significant negative effect on profitability. Operating Expense to Operating Income is the most influential variable among other variables on profitability. The effect of simultaneous NPF, FDR and Operating Expense to Operating Income on profitability  of 75.8% while the remaining 24.2% is the influence of other factors not examined. We can conclude that NPF, FDR and ROA simultaneously positive and significant impact on profitability Bank of sharia in the study period.

JEL Classification: G10, G12, G21

Keywords: FDR, NPF, Profitability, ROA
ANALYSIS OF SMEs COMPETITIVENESS THROUGH THE INNOVATION STRATEGY AND PRODUCT SALE INFORMATION SYSTEM IN THE TRUNAN VILLAGE, MAGELANG CITY
Authors: Prasetyanto Panji Kusuma , Prakoso Jalu Aji , Destiningsih Rian
Published: August 2020

The role of SMEs in development can be obtained through contributions made by SMEs to GRDP. The Trunan Village located in South Magelang Regency is an area that has the largest SME-producing products in the City of Magelang. The problem caused by SMEs in the Trunan Village, Magelang City, is the lack of product innovation in their production goods. Special tofu producer SMEs in Trunan Village, Magelang City lack understanding of the importance of their production. Another problem suspended by MSMEs in Trunan Village, especially tofu producers in developing their business is the information system of selling tofu products. The problem that has been determined will be determined by the specified target. This study aims to determine the importance of applying the innovation of tofu products and tofu sales information systems in business activities. The results showed that there are 3 important things that must be owned by an entrepreneur to be able to innovate, among others: the desire to improve products, services, and entrepreneurial actions. The information system will build a compilation of information patterns that are developed. Business operators must agree on who sends information and receives information. This activity occurs in the exchange of messages in the media information system. Information that is interrelated will cause feedback from the sender and response from the recipient of the message.
Shari’ah Compliances Stock Market Integration: Evidence From Indonesia and Malaysia
Authors: Malini Helma
Published: August 2020

The nature of stock market integration has been an issue for almost a decade; this issue is more complicated toward Shari’ah compliance between countries since there are differences of companies screening process that can be classified as Shari’ah compliances. The differences make the integration of Shari’ah compliances stock market become a major issue in trying to answer the question whether one country can be the placed for Shari’ah portfolio diversification. This study aims to measure Shari’ah compliances integration and portfolio diversification in Indonesia and Malaysia Shari’ah compliances toward other Shari’ah compliances in the world. Six Shari’ah compliances are selected based on countries level of development and geographical factor. This studies relies on two major time series investigation techniques, namely the Auto-Regressive Distributed Lag (ARDL) approach and multi-variate Vector Error Correction Mechanism (VECM), based on the Generalized Methods of Moments (GMM). The ARDL approach is used to determine the existence of long run integration among Shari’ah compliances, while the multi-variate VECM based on the GMM is adopted to provide a robust analysis of short and long-run dynamic causal linkages among the stock markets.

Keywords: Efficient Market Hypothesis, Portfolio Diversification, Shari’ah compliances Integration
Economic Perspective, Cultural Perspectives, and Sharia Perspective in Revenue Sharing For Village Economic Empowerment (Case Study on Gaduh Culture in East Java)
Authors: Anwar Moch. Khoirul , Hariyati Hariyati
Published: August 2020

Theoretically, revenue is one of local wisdom community empowerment models which is effective nowadays. This model is based on potential and social fabric conditions of the local community. The study aims to analyze the influence of the economic perspectives, cultural perspective and sharia perspective on revenue of society’s income in East Java.

This study uses a mixed methods study, with a qualitative and quantitative approach. The population and samples are the society in Blitar, Jombang, and Madiun. The result of the qualitative analysis showed that there are three (3) models of implementasion in cow-calf lease agreement (gaduh) and share farming (paron) system. The first model implements profit sharing system by taking maintenance cost into account. The second model implements sharing system as well but it takes farming workers in the deficit of profit cost into account. The revenue that is based on profit sharing is still in 50:50. While the third model uses revenue sharing system without taking administration and workers cost as the cost component. However, the revenue proportion becomes 75:25. Those models are reviewed from shariah perspective, economic perspective and cultural perspective. From quantitative analysis showed that economic perspective has bigger influence.

Keywords: Economic Perspectives, Mixed Method, Profit Sharing, Revenue, Shariah Perspective
AN EMPIRICAL STUDY OF ISLAMIC MICROFINANCE PERFORMANCE FOR POOR FAMILY: MAQASHID AL-SHARIA PERSPECTIVE
Authors: Nurasyiah Aas
Published: August 2020

This research motivated by Islamic Microfinance performance measurement which still adopting on the performance measurement of microfinance in general that limited to the measurement of material. Therefore, efforts urgently needed to introduce more holistic measurement in assessing the performance of Islamic Microfinance based on tawheed principle. Thus, this study aims to measure the performance of Islamic Microfinance institutions based on Maqashid Al-Sharia. This research method uses quantitative approach with descriptive quantitative research design, which measures variables based on certain indicators. The location of the research is KOPMU-DT as one of the Islamic Microfinance institutions located in Bandung. The population of the study was the members KOPMU-DT wide-spread, among thousand people, but the withdrawal sample technique uses non-probability sampling with a sample of 100 members, based on the criteria that have been determined. Based on the research result, generally the members of KOPMU-DT increased living standards of the family economy and the performance of running micro-businesses. In Maqashid Al-Sharia perspective, the members experience a change in the principles of Ad-Din Al-Aql, A-nafs, An-Nasl and Al-Maal. However, among five principles, Al-Aql increases lower than other principles. In the future, to improve the performance of Islamic Microfinance, especially in KOPMU-DT, needs technical effort / business of accompaniment improvement to develop entrepreneurship from members. In addition, needs to give appreciation to the consistent members and disciplined in order to refund to add its financing to stimulate the operating business, without losing spiritual accompaniment to strengthen the achievement of Maqashid Al-Sharia of the empowerment members of Islamic Microfinance institution.
Keywords: Islamic Microfinance, Maqashid Al-Sharia, Performance
Towards the connection between snow microphysics and melting layer: insights from multifrequency and dual-polarization radar observations during BAECC
Authors: Li Haoran , Tiira Jussi , von Lerber Annakaisa , Moisseev Dmitri
Published: August 2020

Abstract. In stratiform rainfall, the melting layer (ML) is often visible in radar observations as an enhanced reflectivity band, the so-called bright band. Despite the ongoing debate on the exact microphysical processes taking place in the ML and on how they translate into radar measurements, both model simulations and observations indicate that the radar-measured ML properties are influenced by snow microphysical processes that take place above it. There is still, however, a lack of comprehensive observations to link the two. To advance our knowledge of precipitation formation in ice clouds and provide new insights into radar signatures of snow growth processes, we have investigated this link. This study is divided into two parts. Firstly, surface-based snowfall measurements are used to develop a new method for identifying rimed and unrimed snow from X- and Ka-band Doppler radar observations. Secondly, this classification is used in combination with multifrequency and dual-polarization radar observations collected during the Biogenic Aerosols – Effects on Clouds and Climate (BAECC) experiment in 2014 to investigate the impact of precipitation intensity, aggregation, riming and dendritic growth on the ML properties. The results show that the radar-observed ML properties are highly related to the precipitation intensity. The previously reported bright band “sagging” is mainly connected to the increase in precipitation intensity. Ice particle riming plays a secondary role. In moderate to heavy rainfall, riming may cause additional bright band sagging, while in light precipitation the sagging is associated with unrimed snow. The correlation between ML properties and dual-polarization radar signatures in the snow region above appears to be arising through the connection of the radar signatures and ML properties to the precipitation intensity. In addition to advancing our knowledge of the link between ML properties and snow processes, the presented analysis demonstrates how multifrequency Doppler radar observations can be used to get a more detailed view of cloud processes and establish a link to precipitation formation.
Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretion
Authors: Wang Yuwei , Mehra Archit , Krechmer Jordan E. , Yang Gan , Hu Xiaoyu , Lu Yiqun , Lambe Andrew , Canagaratna Manjula , Chen Jianmin , Worsnop Douglas , Coe Hugh , Wang Lin
Published: August 2020

Abstract. Gas-phase oxidation pathways and products of anthropogenic
volatile organic compounds (VOCs), mainly aromatics, are the subject of
intensive research, with attention paid to their contributions to secondary
organic aerosol (SOA) formation and potentially new particle formation
(NPF) in the urban atmosphere. In this study, a series of OH-initiated
oxidation experiments of trimethylbenzene (TMB, C9H12) including
1,2,4-TMB, 1,3,5-TMB, 1,2,3-TMB, and 1,2,4-(methyl-D3)-TMBs
(C9H9D3) were investigated in an oxidation flow reactor
(OFR) in the absence and presence of NOx. Products were measured using
a suite of state-of-the-art instruments, i.e. a nitrate-based chemical
ionization–atmospheric pressure interface time-of-flight mass spectrometer
(nitrate CI-APi-TOF), an iodide-adduct chemical ionization time-of-flight
mass spectrometer (iodide CI-TOF) equipped with a Filter Inlet for Gases and
AEROsols (FIGAERO), and a Vocus proton-transfer-reaction mass spectrometer
(Vocus PTR). A large number of C9 products with 1–11 oxygen atoms and C18
products presumably formed from dimerization of C9 peroxy radicals were
observed, hinting at the extensive existence of autoxidation and accretion
reaction pathways in the OH-initiated oxidation reactions of TMBs. Oxidation
products of 1,2,4-(methyl-D3)-TMBs with deuterium atoms in different methyl
substituents were then used as a molecular basis to propose potential
autoxidation reaction pathways. Accretion of C9 peroxy radicals is the most
significant for aromatics with meta-substituents and the least for aromatics
with ortho-substituents if the number and size of substituted groups are
identical. The presence of NOx would suppress the formation of highly oxygenated molecules (HOMs) of C18 and enhance the formation of
organonitrates and even dinitrate organic compounds. Our results show that
the oxidation products of TMB are much more diverse and could be more
oxygenated than the current mechanisms predict.
Measurement report: Ice nucleating abilities of biomass burning, African dust, and sea spray aerosol particles over the Yucatan Peninsula
Authors: Córdoba Fernanda , Ramirez-Romero Carolina , Cabrera Diego , Raga Graciela B. , Miranda Javier , Alvarez-Ospina Harry , Rosas Daniel , Figueroa Bernardo , Kim Jong S. , Yakobi-Hancock Jacqueline , Amador Talib , Gutierrez Wilfrido , Garcia Manuel , Bertram Allan K. , Baumgardner Darrel , Ladino Luis A.
Published: August 2020

Abstract. Most precipitation from deep clouds over the continents and in the intertropical convergence zone is strongly influenced by the presence of ice crystals, whose formation requires the presence of ice nucleating particles (INP). Although there are a large number of INP sources, the ice nucleating abilities of aerosol particles emitted from oceans, deserts, and wildfires are poorly described at tropical latitudes. To fill this gap in knowledge, the UNAM-MicroOrifice Uniform Deposit Impactor-Droplet Freezing Technique (UNAM-MOUDI-DFT) was built. Aerosol samples were collected in Sisal and Merida, Yucatan (Mexico) under the influence of cold fronts, biomass burning (BB), and African dust (AD), during five short-term field campaigns between January 2017 and July 2018. The three different aerosol types were distinguished by characterizing their physicochemical properties. Marine aerosol (MA), BB, and AD air masses were found to contain INP; the highest concentrations were found for AD (from 0.071 L−1 to 36.07 L−1), followed by MA (from 0.068 L−1 to 18.90 L−1), and BB (from 0.063 L−1 to 10.21 L−1). However, MA had the highest surface active site density (ns) between −15 °C and −30 °C. Additionally, supermicron particles contributed more than 72 % of the total INP concentration independent of aerosol type; MA had the largest contribution from supermicron particles.
High precision laser spectrometer for multiple greenhouse gas analysis in 1 mL air from ice core samples
Authors: Bereiter Bernhard , Tuzson Béla , Scheidegger Philipp , Kupferschmid André , Looser Herbert , Mächler Lars , Baggenstos Daniel , Schmitt Jochen , Fischer Hubertus , Emmenegger Lukas
Published: August 2020

Abstract. The record of past global background atmospheric greenhouse gas composition is crucial for our understanding of global climate change. The ”Beyond EPICA Oldest Ice Core” project is currently pushing the frontier of this knowledge forward by the retrieval of an ice core reaching back to 1.5 million years ago. The oldest section of this core will have been strongly thinned by glacier flow with about 15 kyr being trapped in as little as 1m thickness of ice. This reduces the available sample volume to only a few mL of air for the targeted century-scale resolution of greenhouse gas records. Under these conditions, the required accuracy for multiple greenhouse gases cannot be achieved with currently available analytical methods. Here, we present a new approach to unlocking such challenging atmospheric archives with a high-precision mid-IR dual-laser direct absorption spectrometer. The instrument is designed to simultaneously measure CH4, N2O, CO2 concentrations as well as δ13C(CO2) using discrete samples of only 1 mL STP, and it achieves a precision of 1.6 ppb, 1.0 ppb, 0.03 ppm and 0.04 ‰, respectively. Repeated measurement cycles of air samples demonstrate an excellent accuracy level, and high reproducibility of the spectroscopic and the gas handling system. In addition, this non-invasive method allows reuse of the precious gas samples for further analysis, which opens new opportunities in ice core science.
Can ocean community production and respiration be determined by measuring high-frequency oxygen profiles from autonomous floats?
Authors: Gordon Christopher , Fennel Katja , Richards Clark , Shay Lynn K. , Brewster Jodi K.
Published: August 2020

Abstract. Oceanic primary production forms the basis of the marine food web and provides a pathway for carbon sequestration. Despite its importance, spatial and temporal variations of primary production are poorly observed, in large part because the traditional measurement techniques are laborious and require the presence of a ship. More efficient methods are emerging that take advantage of miniaturized sensors integrated into autonomous platforms such as gliders and profiling floats. One such method relies on determining the diurnal cycle of dissolved oxygen in the mixed layer and has been applied successfully to measurements from gliders and mixed-layer floats. This study is the first documented attempt to estimate primary production from diurnal oxygen changes measured by Argo-type profiling floats, thus accounting for the whole euphotic zone. We first present a novel method for correcting measurement errors that result from the relatively slow response time of the oxygen optode sensor. This correction relies on an in situ determination of the sensor's effective response time. The method is conceptually straightforward and requires only two minor adjustments in current Argo data transmission protocols: (1) transmission of measurement time stamps and (2) occasional transmission of downcasts in addition to upcasts. Next, we present oxygen profiles collected by 10 profiling floats in the northern Gulf of Mexico, evaluate whether community production and respiration can be detected, and show evidence of internal oscillations influencing the diurnal oxygen signal. Our results show that profiling floats are capable of measuring diurnal oxygen variations although the confounding influence of physical processes does not permit a reliable estimation of biological rates in our dataset. We offer suggestions for recognizing and removing the confounding signals.
Water Flow Controls the Spatial Variability of Methane Emissions in a Northern Valley Fen Ecosystem
Authors: Zhang Hui , Tuittila Eeva-Stiina , Korrensalo Aino , Räsänen Aleksi , Virtanen Tarmo , Aurela Mika , Penttilä Timo , Laurila Tuomas , Gerin Stephanie , Lindholm Viivi , Lohila Annalea
Published: August 2020

Abstract. Northern peatlands are projected to be crucial in future atmospheric methane (CH4) budgets and have a positive feedback on global warming. Fens receive nutrients from catchments via inflowing water and are more sensitive than bogs to climate change-caused variations in their ecohydrology. Yet, due to a lack of data detailing the impacts of moving water on microhabitats and CH4 fluxes in fens, there remains large uncertainties in predicting CH4 emissions from these sites. We measured CH4 fluxes with manual chambers over three growing seasons (2017–2019) at a northern boreal fen. To address the spatial variation at the site where a stream flows through the long and narrow valley fen, we established sample plots at varying distances from the stream. To link the variations in CH4 emissions to environmental controls, we quantified water levels, peat temperature, dissolved oxygen concentration, vegetation composition and leaf area index in combination with flux measurements during the growing season in 2019. We found that due to the flowing water, there was a higher water level, lower peat temperatures, and more oxygen in the peat close to the stream, which also had the highest total leaf area and gross primary production (GPP) values but the lowest CH4 emissions. Further from the stream, the conditions were drier and produced low CH4 emissions. In contrast, CH4 emissions were highest at an intermediate distance from the stream where the oxygen concentration in the surface peat was low but GPP was still high. Our results emphasise the key role of ecohydrology in CH4 dynamics in fens, and for the first time show how a stream controls CH4 emissions in a flow-through fen. As valley fens are common peatland ecosystems from the arctic to the temperate zones, future projections of global CH4 budgets need to take flowing water features into account.
COST-BENEFIT ANALYSIS OF RAIL TUNNEL INSPECTION FOR PHOTOGRAMMETRY AND LASER SCANNING
Authors: Panella F. , Roecklinger N. , Vojnovic L. , Loo Y. , Boehm J.
Published: August 2020

Abstract. The civil engineering and construction sector, including the railway industry, is seeking innovative approaches to reduce costs on repetitive and labour-intensive tasks and avoid the use of highly qualified staff for simple manual duties. Such tasks can include the visual inspection of tunnels, where the process is still dominated by manual operations. Our work compares Close Range Photogrammetry (CRP) and Terrestrial Laser Scanning (TLS), both performed with low-end sensors to reflect the industry’s tendency towards easy to use and easy to maintain hardware. It also analyses the benefits of substituting conventional visual inspections of tunnels with automated survey approaches and computer vision techniques. The project’s outcomes suggest that photogrammetry is a valid alternative to laser scanning for visual inspection of concrete segmentally lined tunnels: from the geometric point of view it provides global accuracy at comparable level to laser scanning, in addition it halves the time to generate the 3D model and provides the user with photo-realistic outputs. It is generally more versatile and it is easier to inspect, visualise and navigate the data. The authors argue that the results presented here will push tunnel inspection in the direction of automated approaches with direct benefits on surveying costs as well as Health & Safety (H&S). Utilising available technology supports risk-based asset management and thus ensures safe and operational performance of a railway for passengers to use.
USE OF HISTORICAL AERIAL IMAGES FOR 3D MODELLING OF GLACIERS IN THE PROVINCE OF TRENTO
Authors: Poli D. , Casarotto C. , Strudl M. , Bollmann E. , Moe K. , Legat K.
Published: August 2020

Abstract. Historical aerial images represent a source of information of great value for glacier monitoring, as they cover the area of interest at a well-defined epoch and allow for visual interpretation and metric analysis. Typically, the aerial images are used to produce orthophotos and manually digitize the perimeters of the glaciers for analysis of the surface extent of the glaciers, while the extraction of height information is more challenging due to data quality and characteristics. This article discusses the potential of historical aerial images for glacier modelling. More specifically, it analyses the impact of their coverage, radiometric- and geometric accuracy, state of preservation and completeness on the photogrammetric workflow. The data set used consists of scans of 300 (analog) aerial images acquired between August and October 1954 by the U.S. Air Force with a Fairchild KF7660 camera over the entire Province of Trento. For the modelling of the glaciers, different techniques such as manual stereoscopic measurement and dense image matching were tested on sample glaciers and the results were analysed in detail. Due to local radiometric saturation in a large part of the glacial surfaces and other disturbances affecting the historical images (e.g. scratches, scanning errors, dark shadows), dense image matching did not produce any valuable results, and stereo plotting could be used only on images (or image parts) with acceptable quality. The derived Digital Terrain Models (DTMs) were compared with a reference DTM obtained with dense image matching from digital aerial images acquired in September 2015 with an UltraCam Eagle sensor, and, for some glaciers, to a DTM obtained with dense image matching from scanned aerial images acquired in September 1983 with a RC30 analog camera. The differences between 1954 and 2015 DTMs showed values up to 70–80 m in height and a behaviour that is confirmed by the models employed by the glaciology experts in Trento.
DEEP LEARNING APPLIED TO WATER SEGMENTATION
Authors: Akiyama T. S. , Marcato Junior J. , Gonçalves W. N. , Bressan P. O. , Eltner A. , Binder F. , Singer T.
Published: August 2020

Abstract. The use of deep learning (DL) with convolutional neural networks (CNN) to monitor surface water can be a valuable supplement to costly and labour-intense standard gauging stations. This paper presents the application of a recent CNN semantic segmentation method (SegNet) to automatically segment river water in imagery acquired by RGB sensors. This approach can be used as a new supporting tool because there are only a few studies using DL techniques to monitor water resources. The study area is a medium-scale river (Wesenitz) located in the East of Germany. The captured images reflect different periods of the day over a period of approximately 50 days, allowing for the analysis of the river in different environmental conditions and situations. In the experiments, we evaluated the input image resolutions of 256 × 256 and 512 × 512 pixels to assess their influence on the performance of river segmentation. The performance of the CNN was measured with the pixel accuracy and IoU metrics revealing an accuracy of 98% and 97%, respectively, for both resolutions, indicating that our approach is efficient to segment water in RGB imagery.
Abrupt transitions in an atmospheric single-column model with weak temperature gradient approximation
Authors: Stephens Benjamin A. , Jackson Charles S.
Published: August 2020

Abstract. We document a feature of the tropical atmosphere that could be relevant to episodes of abrupt transitions in global climate that regularly occurred during the last ice age. Using a single-column model (SCM) incorporating the weak temperature gradient (WTG) approximation, we find that abrupt transitions occur as the sea surface temperature is steadily increased. Because these transitions arise from the interplay between local deep convection and the large-scale adjustments that are required to maintain weak temperature and pressure gradients, they are only present with the WTG approximation relevant for the tropics but may be of interest as a trigger for abrupt transitions in global climate. These transitions are marked by an abrupt change in the partitioning of rainfall between convective and large-scale (microphysics) subroutines in addition to various other features of the column, including cloudiness, vertical velocity, temperature, and humidity. We conclude that the transitions are initiated by a failure of evaporative cooling in the lower free troposphere. This leads to lower-column heating and a burst of convection that heats the upper free troposphere, increasing the large-scale rainfall rate, which allows for sufficient evaporative cooling to restabilize the column.
Increasing Frequency in Off-Season Tropical Cyclones and its relation to Climate Variability and Change
Authors: Hernandez Ayala José J. , Méndez-Tejeda Rafael
Published: August 2020

Abstract. This article analyzes the relationship between off-season tropical cyclone (TC) frequency and climate variability and change for the Pacific and Atlantic Ocean basins. TC track data was used to extract the off-season storms for the 1900–2019 period. TC counts were aggregated by decade and the number of storms for the first six decades (pre-satellite era) was adjusted. Mann-Kendall non-parametric tests were used to identify trends in decadal TC counts and multiple linear regression models (MRL) were used to test if climatic variability or climate change factors explained the trends in off-season storms. MRL stepwise procedures were implemented to identify the climate variability and change factors that explained most of the variability in off-season TC frequency. A total of 713 TCs were identified as occurring earlier or later than their peak seasons, most during the month of May and in the West Pacific and South Pacific basins. The East Pacific (EP), North Atlantic (NA) and West Pacific (WP) basins exhibit significant increasing trends in decadal off-season TC frequency. MRL results show that trends in sea surface temperature, global mean surface temperature, and cloud cover explain most of the increasing trend in decadal off-season TC counts in the EP, NA, and WP basins. Stepwise MLR results also identified climate change variables as the dominant forces behind increasing trends in off-season TC decadal counts, yet they also showed that climate variability factors like El Niño-Southern Oscillation, the Atlantic Multidecadal Oscillation, and the Interdecadal Pacific Oscillation also account for a portion of the variability.