bluuebunny/crossref_metadata_2025 huggingface dataset:
Critical Perspective on Agribusiness Supply Chain Management (ASCM) in Developing Nations: What are the Policy and Institutional Lessons for Developing Economies?
Authors: Chukwuma O Ume , Nice N Ihedioha , I Opata Patience , Chukwuchebe U Obiajulu
Published: May 2020

This paper seeks to explore and assess literature on Supply chain management. The overarching aim is to derive institutional and policy lessons for the agribusiness sector, especially among the least developed economies. The focus is to better understand the range of supply chain initiatives prevalent in literature and how they fit into the developing nations contexts. Unpacking what supply chain initiatives exist in scholarly publications is relevant since scholarly ideas often shape institutional and policy directions and negotiations in the agricultural sector interventions. Using subjective criteria, sourcing, screening and selection of documents, and conducting qualitative analysis and validation were done. In exploring this discourse, we observe the emergence of a variety of overarching initiatives – development of short food supply chains, supply chain partnership, and supply chain integration. Findings from the study suggest that there is a need for some level of coordination of processes and activities within and between agribusiness firms in the supply chain, in order to build a stronger agribusiness subsector.
An Assessment of Compliance with Disclosure Requirements of IAS 41 (Agriculture) By Listed Agricultural Firms in Nigeria
Authors: Ibrahim Nura , Kurfi Shafi’u Abubakar
Published: May 2020

This study examined the extent of compliance with disclosure requirements of IAS 41 by agricultural companies listed on the Nigerian Stock Exchange (NSE) for the period of 5 years (2013-2017). The data for the study were obtained from the published financial statements of the sampled firms for the period under review from which a compliance index were constructed, The tools for analysis used were the qualitative grading using a compliance index and the one way ANOVA purposely to test the hypotheses proposed. The study observed that three out of the four Companies achieved more than 70% with overall mean scores of 76.02%. This shows that majority of the agricultural firms in Nigeria strongly complied with the disclosure requirements of IAS 41. Based on the findings the study recommends among others that firms should strive at all times to comply with all regulatory and statutory requirement in the preparation and presentation of financial statements, giving the fact that it is a set of documents that prescribe the performance of the reporting entity. The Financial Reporting Council of Nigeria should publish annually the compliance status of all listed firms in Nigeria; so that the compliance status of every firm will become known to all interested users of financial statements; and also the Council should urge external  auditors of firms to ensure that their clients are complying with the requirements of IASs issued by the International Accounting Standards Board (IASB).
Influence of Inorganic Fertilizer (NPK 15:15:15) and Cacao (Theobroma cacao L) Leaf Litter Application Rates on Cowpea (Vigna unguiculata L.) Performance in the Tropics
Authors: Ojimgba Onwuchekwa
Published: May 2020

Influence of inorganic fertilizer (NPK 15:15:15) and cacao (Theobroma cacao L.) leaf litter application rates on cowpea (Vigna unguiculata L.) performance in the tropics was studied for 24 months (January, 2017 – December, 2018) at Cocoa Research Institute of  Nigeria (CRIN) Ibeku Sub-Station, Umuahia, Nigeria. Three 3 x 3 factorial experiments, each in a Randomized Complete Block Design (RCBD) with three replicates/blocks were used to study the responses of cowpea to three NPK  15:15:15 fertilizer rates 0 kg, 500 kg and 1000 kg ha-1 represented by (Factor F) F0, F1 and F2, respectively, and cocoa leaf litter rates 0 t, 10 t and 20 t  ha-1   which were also  represented by Lo, L1 and L2  (Factor L), respectively. The results obtained from the study show that the application of either 10 or 20 t ha-1 cocoa leaf litter alone or complementary application of either  10 or 20 t ha-1 cocoa leaf litter plus 500 or 1000 kg ha-1 NPK 15:15:15 fertilizer  significantly increased the various cowpea growth and yield components than the fertilizer rates alone. The treatment without fertilizer and leaf litter, i.e. topsoil only (F0L0) gave significantly the least cowpea growth and yield components. The highest values were obtained with the application of 1000 kg ha-1 NPK 15:15:15 fertilizer with 20 t ha-1 cocoa leaf litter (F2L2). The cowpea crop performance in terms of growth, yield and yield components over the study periods, 2017 and 2018 were statistically similar. Therefore, the inclusion of leaf litter has greater potential for improving cowpea yield than when fertilizer was used alone.  Leaves are potential sources of valuable nutrients providing a high quality of organic matter, which should be returned to the soil.
General Diaz Process, Industrial Diaz
Authors: Banki Lamenra  Hodar
Published: May 2020

According to general essential  of colorant  of azo  derivatives  and  structure, releasing  the substitution of the azo components  by  electron attracting groups produces required activity  enables to get    blue shades from structures .
Important of Azoles
Authors: Zakaria Medhat  Mahamed
Published: May 2020

Azoles are one of a cyclic  derivatives  of chemical  heterocyclic chemical and organic compounds including g a five member di unsaturated ring structure composed of  bi  nitrogen atoms at position (3 and 4) and one sulfur atom at position (1).

 

 

 

 Most of prepared  work on the four thiadiazoles has been on the 1, 3, 4-thiadiazoles. Physical, theoretical, and spectroscopic properties have been reviewed .
Physical Properties of Cyclestructure
Authors: Muhammad Mohed  Ahmad
Published: May 2020

Azo – cyclic   derivatives   are a part   from a ring that has more than type of atoms. Nitrogen, oxygen and sulfur are often found along with carbon in heterocycles rings.

Heterocycles  derivatives  are common in chemical  chemistry, and many have fulfilled important physiological  active  in plant and animal kingdoms and have an important biological properties, such as, the antibiotic penicillin, sedative phenabarbital, and sugar replacing  reagent saccharin, all having heterocycles ring.
Microbial Behavior of Imine Compounds on Bacteria
Authors: Ali Wisam Hassan
Published: May 2020

In  our  past  studies , some  imine  compounds  were prepared  m investigated , spectral  characterization  , it  gave good  evidence  for formation these   compounds , but in this  studying  , these  imine  derivatives  were   screened  against  some types  of   bacteria  and  microbes.
Bacteriology of Diarrhoeic Infection among Primary School Pupils in Akoko South West Local Government Area in Ondo State, Nigeria
Authors: A.O. Ajayi , A.H. Alawode
Published: May 2020

This study shows the bacteriological investigations of Diarrhoeal diseases among selected children who were between the ages of 0 – 14 years. Stool samples from primary school pupils in Akoko South West Local Government Area in Ondo State, Nigeria were used for this purpose. The organisms were isolated and identified using cultural and biochemical test. Isolates obtained were subjected to some antibiotic susceptibility testing. Out of total number of 120 samples examined only 40 (33.3%) of primary school pupils were found to have Diarrhoea associated with bacteria in which 17 (42.5%), 15 (42.5%), and 8(32.5%) were from 0-4 years, 5-9 years and 10-14 years respectively. The Bacteria species isolated include Escherichia coli were the most predominant microorganism. This is followed by Staphylococcus aureus, Bacillius cereus and Vibro cholerae respectively. As at the time of the study, there was significance difference between male and female gender with the male having high incidence of 55.0%. Among the antimicrobials used sparfloxacin and cefuroxime was most effective against Gram negative and Gram postive bacteria respectively. Also, most of the children tested were found to have common illness with clinical manifestations of diarrhoea followed by dysentery, abdominal pain and fever which may be accompanied with vomiting. Severity of infections varies with individual.
Debt Financing and Corporate Finance Performance: A Dynamic Investigation from Nigeria Quoted Firms
Authors: Onyinyechi Uzokwe Grace
Published: May 2020

There are two components of corporate capital. This paper examined the effect of debt financing on the financial performance of quoted firms in Nigeria stock exchange using time series data from 2000-2017. The objective was to examine the controversial findings of scholars on the effect of capital structure on corporate performance of firms.  Return on assets and return on equity was modeled as the function of debt equity ratio, debt ratio, equity ratio, total liability ratio and long term debt ratio. Multiple regressions with the aid of statistical package for social sciences were used as data analysis techniques. Model one found that a correlation coefficient (r) of .872 this implies that a very strong correlation exists between return on assets and explanatory variables. The coefficient of determination (r²) is .678 which shows that 67.8% of the variation in Return on Assets is attributable to the variations in the financial leverage. Also, the F- value calculated of 8.338 has a correlation corresponding value of .004 which implies a good model utility. The test of significance conducted as shown in the tables above states that ROA has a calculated value of 242.032 and a corresponding significance value/probability value of .014.   The positive sign of t-value (1.653) shows the direction of the variables. This therefore implies that when a financial leverage is well used, this leads to a better, reliable and fairer financial result that is objective and represent the true state of affairs in the food and beverage companies proportionately. Model two found that a correlation coefficient (r) of .772 this implies that a very strong correlation exists between return on assets and explanatory variables. The coefficient of determination (r²) is .639 which shows that 63.9% of the variation in return on equity   is attributable to the variations in the financial leverage. Also, the F- value calculated of 7.644 has a correlation corresponding value of .004 which implies a good model utility. The test of significance conducted as shown in the tables above states that ROE has a calculated value of 568.906 and a corresponding significance value/probability value of .003.  The positive sign of t-value (3.310) shows the direction of the variables. This therefore implies that when a financial leverage is well used, this leads to a better, reliable and fairer financial result that is objective and represent the true state of affairs in the food and beverage companies proportionately. We recommend that management of the firms should work very hard to optimize the capital structure in order to increase the returns on equity and assets and that Management of Nigerian firms should increase their commitments into capital structure in order to improve earnings from their business transaction.
Effect of Non-Performing Loans on the Financial Performance of Commercial Banks in Nigeria
Authors: Gabriel Okoh , Victor Inim Ekemini , Innocent Idachaba Odekina
Published: May 2020

The study examined the effect of Non-Performing Loans on the financial performance of commercial banks in Nigeria between the periods of 1985 to 2016. The study employed the multiple regression techniques to analyze data collated from the Central Bank of Nigeria (CBN) statistical bulletin and Nigeria Deposit Insurance Corporation (NDIC) publications for various years. The result of the study shows that Non-Performing Loans to Total Loans ratio (NPL/TLR) and Cash Reserve Ratio (CRR) had statistically negative significant effect on Return on Asset (ROA). These result shows that a high level of non-performing loans would reduce the financial performance of commercial banks in Nigeria. Consequently, the study recommends that the regulatory authorities in Nigeria should create and support an environment where commercial banks in Nigeria can have a strong risk management practices.
Revenue Mobilization and Investment on Basic Amenities of Local Governments in Nigeria
Authors: Captain Briggs Alasin , Ofurum C. O.
Published: May 2020

This paper examined the effects of revenue mobilization and investment on basic amenities of local government in Nigeria. Secondary data were collected from the Central Bank of Nigeria Annual Statistical Bulletin from 19932017. Investment in basic amenities was proxy by monetary value of basic amenities while revenue mobilization was proxy by federal government allocation, state government allocation, value added tax, internally generated revenue and grants to local governments in Nigeria. Ordinary Least Square (OLS), Augmented Dickey Fuller Test, Johansen Co-integration test, normalized co-integrating equations, parsimonious vector error correction model and pair-wise causality tests were used to conduct the investigations and analysis. The empirical findings based on the models found that value added tax, internally generated revenue and grant have negative and significant effect on investment on basic amenities while federal allocation and state allocation have positive effect on the value of basic amenities. The unit root result (ADF) showed that the variables were stationary at the first difference of Order 1 (1). The co-integration tests revealed a long run dynamic relationship between the dependent and independent variables in the models. The parsimonious model summary shows that accounting bases explains a strong and positive significant relationship between the dependent and independent variables. However, the direction of causality between the accounting bases treasury management is mixed indicating uni and bi-directional causality. The study concludes that local government revenue has significant effect on investment of basic amenities of Nigeria local governments.
Focus Constructions in Ǹjò̩-kóo
Authors: Olaogun Simeon O.
Published: May 2020

Focusing is a universal syntactic phenomenon. That is, there is no language in the world that does not have a means of placing prominence on constituents for focus purposes. However, the formal expression of focus differs from one language to another. Some languages express focus morphologically by using distinct morphemes or elements while others employ suprasegmentally means. The paper, therefore examines the focus strategies in Ǹjò̩-Kóo. It gives a detailed description of different constituents that may be focused in the language and the changes that are triggered in the clause as a result of the focusing. Adopting the Minimalist Program of Chomsky (1995) and Cartographic analysis of Rizzi (1997) Split-CP projections within the clausal left periphery, the study investigates how focus clauses are derived in the language and reveals that the syntax of focus in the language involves two probes: focus (foc) and emphasis (emph) each of which can provoke displacement operations. The paper employs information and clause structure evidence to motivate the constituents being focused. It is also observed among other things, that the constituents that could be focused in Ǹjò̩-kóo are subject DP, object DP or object DP of preposition, possessor DP and a whole sentence, and that the language does not distinguish between sentence and verbal focus hence the same strategy is employed for both focus types.
The Relationship between Online Interaction and Academic Performance of Distance E-Learners in a Nigerian University
Authors: Aboderin Olukayode Solomon , Laleye A.M
Published: May 2020

Distance e-learners are expected to participate in an e-learning environment and interact with the content, colleagues and facilitators through distance education technologies. Learning environment goes a long way to determine student’s academic performance. Hence, this study tends to find out relationship between online interaction and distance e-learners. The purpose of the study was to analyze the correlation that exists between learner-content-interaction (LCI), learner-learner-interaction (LLI) and learner-instructor-interaction (LII) and academic performance of distance e-learners in a Nigerian university. Two research questions were designed to guide the study.  A descriptive design of survey type was adopted for the study and a questionnaire was used to collect the quantitative data. The study was conducted in four selected study centres of National Open University of Nigeria (NOUN) and a total of 1,025 participants completed the survey-based questionnaire. The researchers used Spearman’s correlation to determine if correlation exists on each type of interaction. The findings of this study revealed that learner-learner-interaction was the only factor that was significant(r = .066, p-value = .034), with very small weak correlation out of the three types of interactions discussed in this study. Findings also revealed that all the three types of interactions were significant (LCI, r= .121** p=0.009; LII, r=.108*, p=0.018; LLI, r = .105*, p = 0.023) for female distance e-learners but none was significant for male distance e-learners.Based on the findings of the research, recommendations have been made which will assist Nigerian university policy makers and course developers with a view to improving the academic performance of distance e-learners.
Attaining a Lifelong and Equitable Literate Society: The Challenges of National Policies on Education for All
Authors: Ayimoro Oluwatoyin Dorcas
Published: May 2020

Evidence abounds on the fact that literacy and education are important for a developed State. Also, there are global records on the movement to a knowledge based economy rather than a resource based. Thus, globally efforts are being put in place to achieve a considerable percentage of literacy among citizens if not for all because  a nation that refuses to place high premium on the education of her citizenry may be toying with her level of development. Nigeria is endowed with a rich culture and indigenous education but colonization disrupted the system she would have built upon to sustain her own philosophy. She is a signatory to policy documents on the attainment of Education for All (EFA). However, despite the institution of several policies on the promotion of literacy education from pre-independence till- date, Nigeria is still battling with a large population of illiterates especially, among its females; gender inequality and less development is evident in the society. This is a reflection of inadequate attention to lifelong learning opportunities for the citizenry.  Policy formulation without adequate commitment towards development from all stakeholders also pervades the Nigerian society. This, question arise, will Universal Basic Education (UBE) thrive, especially within the context of the Sustainable  Development Goals (SDGs)   taking into cognizance, the past history and the present situation on the approach to enhancing lifelong and inclusive EFA in Nigeria?  Can the Universal Basic Education enhance an equitable society which will create an enabling environment for an all-round oriented sustainable development with equal opportunities for all? More so, education is essential for societal development. This paper thus examine past education initiatives of the Nigerian government within the context of enhancing a lifelong well informed egalitarian society.
Knowledge and Perception of Secondary School Teachers on Global Warming in Ibadan Oyo State, Nigeria
Authors: Oladapo Samuel Olanrewaju
Published: May 2020

This study examines the Knowledge level of teachers in Ibadan on global warming, the factors influence it and how they perceived it. Questionnaire was used as the main instrument for data collection. It was designed to elicit information on the basis of research questions set for this study. A total number of 450 teachers were used as the sample size. Descriptive statistics such as simple percentages and frequency counts were used in the analysis of the research data collected. The study revealed that teachers have knowledge on global warming and aware of its threat to human existence. It was observed that the source of their knowledge on global warming by teachers include the media and attendance at conferences and workshops. As a result of the above findings, it was recommended that efforts should be made to make relevant and up-to-date information on global warming available to the teachers. Emphasis should be made to make the teachers participate in programmes that address adaptation policies on global warming.
Needs Analysis in ESP Context: A Project in English for Specific Purpose: English Writing Course for Diploma Students in Management
Authors: Zaheer Zia ur Rahman , Alokozay Wahidullah , Atifnigar Hamza
Published: May 2020

This study aims to analyse the needs of Management students for English for Specific Purpose (ESP) course as well as to design an ESP course for the Management students. In addition, this research is carried out to answer the research questions; 1. What is the importance of the use of English in management program? 2. What are the most important language skills used in Management program? 3. What is the frequency of the language skills used in management program? 4. What is the level of students’ performance based on the academic task? The findings of the study indicated that the use of English is very important as it is used in every task related to management. The students revealed that they have to give presentations in English and have discussions with peer in English. The listening skills are known to be least used in management program. Furthermore, the findings revealed that the students mostly have some difficulty in completing speaking tasks in their program.
Self-Image as Predictor of Stigma Consciousness among Physically Challenged Students in Tertiary Institutions in Oyo State, Nigeria
Authors: Abdulmojeed Somotan Oluwayomi , Olusegun Atoyebi Adeola
Published: May 2020

The study investigated the levels of stigma consciousness among physically challenged students in tertiary institutions in Oyo State. It ascertained the effect of stigma consciousness on the academic performance of physically challenged students. Also, the study determined the relative influence of self-image on stigma consciousness of physically students. Furthermore, it examined the influence of self-image on stigma consciousness of physically challenged students. These were with a view to providing information on the factors that could influence stigma consciousness of the physically challenged students. The study adopted the descriptive survey research design. The population for the study comprised physically challenged students in tertiary institutions in Oyo State. Three institutions (University of Ibadan, The Polytechnic Ibadan and Emmanuel Alayande College of Education, Oyo) were purposively selected within Oyo State because they have the physically challenged students. A sample size of 120 physically challenged students were selected from the institutions using proportionate random sampling technique. One adapted instrument with two scales was used to collect data from the students. The scales were “Stigma Consciousness Scale (SCS) and Self-Image Questionnaire (SIQ). Data collected were analysed using percentage, frequency counts, one-way ANOVA and multiple regressions. The results of the study showed that 4.8%, 88.6%, 6.7% of tertiary institutions in Oyo State demonstrated low, moderate and high levels of stigma consciousness respectively. The results showed that there was no significant effect of stigma consciousness on the academic performance of the physically challenged students (F (2.102) =0.059, p=0.943). It was also discovered that there was a significant positive influence of self-image on stigma consciousness of physically challenged students (N=105, t= 0.198, p< 0.05). Finally, the results showed that the self-image (β =0.019, F=1.98, p<0.05) contributed significantly in influencing stigma consciousness with coefficient of multiple regression (R2) of 0.164  at p < 0.05. It was concluded that self-image could influence stigma consciousness among physically challenged students in tertiary institutions.
SET for E-commerce Transactions
Authors: Miajee Md. Rezaul Karim
Published: May 2020

The Secure Electronic Transaction (SET) is a convention intended for ensuring Visa exchanges over the Internet. It is an industry-supported standard that was shaped by Master Card and Visa (going about as the administering body) in February 1996. To advance the SET standard all through the installments network, exhortation and help for its improvement have been given by IBM, GTE, Microsoft, Netscape, RSA, SAIC, Terisa and VeriSign. SET depends on cryptography and X.509 v3 computerized certiﬁcates to guarantee message conﬁdentiality and security. SET is the main Internet exchange convention to give security through validation. It battles the danger of exchange data being changed in travel by keeping data safely encoded consistently and by utilizing computerized certiﬁcates to confirm the personality of those getting to installment points of interest. The speciﬁcations of and approaches to encourage secure installment card exchanges on the Internet are completely investigated in this paper.
Los barrios de origen industrial ante el desafío de la desindustrialización. El "ponent" de Tarragona, entre la marginalidad y el anhelo urbano
Authors: Zaguirre Fernández Juan Manuel , Solé Gras Josep Maria
Published: May 2020

El interés de esta propuesta de comunicación radica en revelar los desafíos entre la Tarragona (España) compacta de límites históricos, reconocibles y consolidados y sus barrios dispersos de origen industrial. Sobre terrenos cuarterados “entrevías”, y apoyándose sobre la nueva geometría impuesta por las lógicas de la infraestructura de la movilidad, se desplegó una condición periférica que la ciudad ignoró y de la que rápidamente se apropiaron las fuerzas productivas. Hoy, ante el desafío de la desindustrialización y sus derivadas urbanas en estos barrios de origen industrial, la investigación aborda tanto los efectos de la renuncia de la ciudad de Tarragona a incorporar esta periferia en términos de vulnerabilidad y segregación derivada como la dualidad generada con ello en términos de paisaje resultante. Bajo esta perspectiva, y con el fin de averiguar y comprender esta anomalía, deducimos que, para el caso de Tarragona, existió –y existe todavía– un “orden inverso”, es decir, que la construcción de la periferia emana desde el territorio hacia la ciudad y no de la ciudad al territorio, motivando un desarrollo en paralelo de estas dos dinámicas. El resultado ha sido la emergencia de un “Distrito Distinto” que está rebasando las expectativas industriales y que de su correcto manejo depende la solución de esta controversia. En este sentido, la parte final de esta investigación explora posibles líneas estratégicas de transformación de unos suelos de alto valor urbano, productivo, social y de paisaje cuya imagen está por redibujar.
Determinantes do nível de divulgação das informações por segmento (CPC 22) das empresas brasileiras de capital aberto listadas no IBrX-50
Authors: Nunes Priscila Pontes , Santos Odilanei Morais dos , Marques José Augusto Veiga da Costa
Published: May 2020

Este estudo verificou quais características corporativas são relacionadas com o índice de divulgação (ID) das empresas referente as informações por segmentos requeridas pelo CPC 22. Realizou-se um estudo com dados de 2010 a 2016 de empresas listadas no índice IBrX-50. Aplicou-se um checklist contendo os requerimentos do CPC 22 e utilizou-se uma regressão MQO para identificar as determinantes sobre o índice de divulgação. Foi evidenciado um ID médio total de 57,72%, com média máxima de 86,55% e mínima de 28,59%. As variáveis endividamento, quantidade de segmentos reportados, divulgação primária das informações por região geográfica e clientes significativos foram estatisticamente significantes e com sinais esperados, enquanto as demais variáveis não foram significativas ou tiveram sinais invertidos. Os resultados contribuem para o entendimento do nível de divulgação das empresas brasileiras em relação as informações por segmentos e suscita questionamentos sobre a relevância dos itens de evidenciação requeridos pelo CPC 22.
Characterization of carbonaceous aerosols in Singapore: insight from black carbon fragments and trace metal ions detected by a soot particle aerosol mass spectrometer
Authors: Rivellini Laura-Hélèna , Adam Max Gerrit , Kasthuriarachchi Nethmi , Lee Alex King Yin
Published: May 2020

Abstract. Understanding sources and atmospheric processes that can influence
the physiochemical properties of carbonaceous aerosols is essential to
evaluate their impacts on air quality and climate. However, resolving the
sources, emission characteristics, and aging processes of carbonaceous
aerosols in complex urban environments remains challenging. In this work, a
soot particle aerosol mass spectrometer (SP-AMS) was deployed to
characterize organic aerosols (OAs), refractory black carbon (rBC), and trace metals in
Singapore, a highly urbanized city with multiple local and regional air
pollution sources in the tropical region. rBC (C1+–C9+)
fragments and trace metal ions (K+, Na+, Ni+, V+, and
Rb+) were integrated into our positive matrix factorization of OA. Two
types of fossil fuel combustion-related OAs with different degrees of
oxygenation were identified. This work provides evidence that over 90 % of
rBC originated from local combustion sources with a major part related
to traffic and ∼30 % associated with fresh
secondary organic aerosol (SOA) produced under the influence of shipping
and industrial emission activities (e.g., refineries and petrochemical
plants) during daytime. The results also show that ∼43 % of
the total rBC was emitted from local traffic, while the rest of the rBC fraction
stemmed from multiple sources including vehicular sources, shipping, and industrial
emissions, but was not fully resolved. There was only a weak association
of the cooking-related OA component with rBC. Although there was no
observable biomass burning episode during the sampling period, K+ and
Rb+ were mainly associated with the more oxidized oxygenated OA
component, indicating the potential contribution of regional biomass burning
and/or coal combustion emissions to this aged OA component. Furthermore, the
aerosol pollutants transported from the industrial area and shipping ports
presented higher C1+/C3+ and V+/Ni+ ratios than
those associated with traffic. The observed association between Na+ and
rBC suggests that the contribution of anthropogenic emissions to total
particulate sodium should not be ignored in coastal urban environments.
Overall, this work demonstrates that rBC fragments and trace metal ions can
improve our understanding of the sources, emission characteristics, and
aging history of carbonaceous aerosol (OA and rBC) in this type of complex
urban environment.
Attribution of ground-level ozone to anthropogenic and natural sources of NOx and reactive carbon in a global chemical transport model
Authors: Butler Tim , Lupascu Aurelia , Nalam Aditya
Published: May 2020

Abstract. We perform a source attribution for tropospheric and ground-level ozone using a novel technique which accounts separately for the contributions of the two chemically distinct emitted precursors (reactive carbon and oxides of nitrogen) to the chemical production of ozone in the troposphere. By tagging anthropogenic emissions of these precursors according to the geographical region from which they are emitted, we determine source/receptor relationships for ground-level ozone. Our methodology reproduces earlier results obtained through other techniques for ozone source attribution, and also delivers additional information about the modelled processes responsible for intercontinental transport of ozone, which is especially strong during the spring months. The current generation of chemical transport models used to support international negotiations aimed at reducing the intercontinental transport of ozone show especially strong inter-model differences in simulated springtime ozone. Current models also simulate a large range of different responses of surface ozone to methane, one of the major precursors of ground-level ozone. Using our novel source attribution technique, we show that emissions of NOx from international shipping over the high seas play a disproportionately strong role in our model system to the hemispheric-scale response of surface ozone to changes in methane, as well as to the springtime maximum in intercontinental transport of ozone and its precursors. We recommend a renewed focus on improvement of the representation of the chemistry of ship NOx emissions in current-generation models. We demonstrate the utility of ozone source attribution as a powerful model diagnostic tool, and recommend that similar source attribution techniques become a standard part of future model inter-comparison studies.
Airborne measurement of peroxy radicals using chemical amplification coupled with cavity ring-down spectroscopy: the PeRCEAS instrument
Authors: George Midhun , Andrés Hernández Maria Dolores , Nenakhov Vladyslav , Liu Yangzhuoran , Burrows John Philip
Published: May 2020

Abstract. Hydroperoxyl (HO2) and organic peroxy (RO2) radicals have an unpaired spin and are highly reactive free radicals. Measurements of the sum of HO2 and RO2 provide unique
information about the chemical processing in an air mass. This paper
describes the experimental features and capabilities of the Peroxy Radical
Chemical Enhancement and Absorption Spectrometer (PeRCEAS). This is an
instrument designed to make measurements on aircraft from the boundary layer
to the lower stratosphere. PeRCEAS combines the amplified conversion of
peroxy radicals to nitrogen dioxide (NO2) with the sensitive detection
of NO2 using cavity ring-down spectroscopy (CRDS) at 408 nm.
PeRCEAS is a dual-channel instrument, with two identical reactor–detector
lines working out of phase with one another at a constant and defined
pressure lower than ambient at the aircraft altitude. The suitability of
PeRCEAS for airborne measurements in the free troposphere was evaluated by
extensive characterisation and calibration under atmospherically
representative conditions in the laboratory. The use of alternating modes of
the two instrumental channels successfully captures short-term variations in
the sum of peroxy radicals, defined as RO2∗
(RO2∗=HO2+∑RO2+OH+∑RO, with R being an
organic chain) in ambient air. For a 60 s measurement, the RO2∗
detection limit is < 2 pptv for a minimum (2σ) NO2
detectable mixing ratio < 60 pptv, under laboratory conditions in
the range of atmospheric pressures and temperatures expected in the free
troposphere. PeRCEAS has been successfully deployed within the OMO
(Oxidation Mechanism Observations) and EMeRGe (Effect of Megacities on the
transport and transformation of pollutants on the Regional and Global
scales) missions in different airborne campaigns aboard the High Altitude LOng range
research aircraft (HALO) for the study of the composition of the free
troposphere.
Biogeography and community structure of abyssal scavenging Amphipoda (Crustacea) in the Pacific Ocean
Authors: Patel Tasnim , Robert Henri , D'Udekem D'Acoz Cedric , Martens Koen , De Mesel Ilse , Degraer Steven , Schön Isa
Published: May 2020

Abstract. In 2015, we collected more than 60 000 scavenging amphipod specimens
during two expeditions to the Clarion–Clipperton fracture zone (CCZ) in the
Northeast (NE) Pacific and to the DISturbance and re-COLonisation (DisCOL)
experimental area (DEA), a simulated mining impact disturbance proxy in the
Peru Basin in the Southeast (SE) Pacific. Here, we compare biodiversity patterns
of the larger specimens (>15 mm) within and between these two
oceanic basins. Eight scavenging amphipod species are shared between these
two areas, thus indicating connectivity. Overall diversity was lower in the
DEA (Simpson index, D = 0.62), when compared to the CCZ (D=0.73), and
particularly low at the disturbance site in the DEA and the site
geographically closest to it. Local differences within each basin were
observed too. The community compositions of the two basins differ, as
evidenced by a non-metric dimensional scaling (NMDS) analysis of beta
biodiversity. Finally, a single species, Abyssorchomene gerulicorbis (Schulenberger and Barnard, 1976),
dominates the DEA with 60 % of all individuals.
New insights into mechanisms of sunlight-mediated high-temperature accelerated diurnal production-degradation of fluorescent DOM in lake waters
Authors: Liu Yijun , Yuan Jie , Yue Fu-Jun , Li Si-Liang , Wang Baoli , Mohinuzzaman Mohammad , Yang Xuemei , Senesi Nicola , Lao Xinyu , Li Longlong , Liu Cong-Qiang , Ellam Rob M. , Mostofa Khan M. G.
Published: May 2020

Abstract. The production of fluorescent dissolved organic matter (FDOM) produced from phytoplankton and its subsequent degradation both of which occur constantly under diurnal-day time sunlight and by night time dark-microbial processes, influence markedly several biogeochemical processes and functions in aquatic environments and can be feasibly related to global warming (GW). In this work sunlight-mediated high-temperature was shown to accelerate the production of FDOM, but also its complete disappearance over a 24-h diurnal period in July, but not in lower temperature months. In July, extracellular polymeric substances (EPS), an early-state DOM, were produced from phytoplankton in early morning (06:00–09:00), then were degraded into four FDOM components over midday (10:00–15:00), which was followed by simultaneous production and almost complete degradation of FDOM with reformation of EPS during night time (02:00–06:00). Such transformations occurred simultaneously with the fluctuating production of nutrients (NH4+, NO3−, NO2−, PO43− and dissolved Si), dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and the two isotopes (δ15N and δ18O) of NO3−. The FDOM components identified by fluorescence excitation-emission matrix (EEM) spectroscopy combined with parallel factor (PARAFAC) analysis consisted of EPS, autochthonous humic-like substances (AHLS) of C and M types distinctly, a combined form of C and M types of AHLS, protein-like substances (PLS), newly-released PLS, tryptophan-like substances (TLS), tyrosine-like substances (TYLS), a combined form of TYLS and phenylalanine-like substances (PALS), as well as their degradation products. Finally, stepwise degradation and production processes are synthesized in a pathway for FDOM components production and their subsequent transformation under different diurnal temperature conditions, which provided a broader paradigm for future impacts on GW-mediated DOM dynamics in lake water.
Predicting evapotranspiration from drone-based thermography – a method comparison in a tropical oil palm plantation
Authors: Ellsäßer Florian , Stiegler Christian , Röll Alexander , June Tania ,   Hendrayanto, Knohl Alexander , Hölscher Dirk
Published: May 2020

Abstract. For the assessment of evapotranspiration, near-surface airborne thermography offers new opportunities for studies with high numbers of spatial replicates and in a fine spatial resolution. We tested drone-based thermography and the subsequent application of three energy balance models (DATTUTDUT, TSEB-PT, DTD) using the widely accepted eddy covariance technique as a reference method. The study site was a mature oil palm plantation in lowland Sumatra, Indonesia. For the 61 flight missions, latent heat flux estimates of the DATTUTDUT model with measured net radiation agreed well with eddy covariance measurements (r² = 0.85; MAE = 47; RMSE = 60) across variable weather conditions and daytimes. Confidence intervals for slope and intercept of a model II Deming regression suggest no difference between drone-based and eddy covariance method, thus indicating interchangeability. TSEB-PT and DTD yielded agreeable results, but all three models are sensitive to the configuration of the net radiation assessment. Overall, we conclude that drone-based thermography with energy-balance modeling is a reliable method complementing available methods for evapotranspiration studies. It offers promising, additional opportunities for fine grain and spatially explicit studies.
A Prequel to the Dantean Anomaly: The Water Seesaw and Droughts of 1302–1307 in Europe
Authors: Bauch Martin , Labbé Thomas , Engel Annabell , Seifert Patric
Published: May 2020

Abstract. The cold/wet anomaly of the 1310s (Dantean anomaly) has attracted a lot of attention from scholars, as it is commonly interpreted as a signal of the transition between the MCA and the LIA. The huge variability that can be observed during this decade, similarly with the high interannual variability observed in the 1340s, has been highlighted as a side-effect of this rapid climatic transition. In this paper, we demonstrate that a multi-seasonal drought of almost two years occurred in the Mediterranean between 1302 and 1304, and respectively a series of hot and dry summers north of the Alps from 1304 to 1306. We propose to interpret this outstanding dry anomaly, unique in the 13th/14th century, combined with the 1310s and the 1340s cold anomalies, as part of the climatic shift from the MCA to the LIA. Our reconstruction of the predominant weather patterns of the first decade of the 14th century from documentary and proxy data lead to the identification of multiple European water seesaw events in 1302–1307, with similarities to the seesaw conditions which prevailed in 2018 over continental Europe. It can be debated to which extent the 1302–1307 period can be compared to what is currently discussed regarding the influence of the Arctic amplification phenomenon on the increasing frequency of long-lasting stable weather patterns that occurred since the late 1980s. Additionally, this paper deals with socio-economic and cultural responses to drought risks in the Middle Ages from contemporary sources and provides evidence that there is a significant correlation between blazes that devastated cities and pronounced dry seasons.
Climate records in ancient Chinese diaries and their application in historical climate reconstruction – A case study of Yunshan Diary
Authors: Chen Siying , Su Yun , Fang Xiuqi , He Jia
Published: May 2020

Abstract. Private diaries are important sources of historical data for research on climate change. Their advantages include a high veracity and reliability, accurate time and location information, a high temporal resolution, seasonal integrity, and rich content. In particular, these data are suitable for reconstructing short-term, high-resolution climate series and extreme climatic events. Through a case study of Yunshan Diary, authored by Bi Guo of the Yuan Dynasty of China, this article demonstrates how to delve into climate information in diaries, including species distribution records, phenological records, daily weather records, and perception records. In addition, this article considers how to use these records, supplemented by other data, to reconstruct climate change and extreme climatic events on various time scales, from multi-decadal to annual to daily. The study of Yunshan Diary finds that there was a relatively low amount of precipitation in central and southern Jiangsu Province in the summer of 1309; the winter of 1308–1309 was abnormally cold in the Taihu Lake Basin. In the early 14th century at the latest, the climate in eastern China had begun to turn cold, which reflects the transition from the Medieval Warm Period to the Little Ice Age.
Historical porosity data in polar firn
Authors: Fourteau Kévin , Arnaud Laurent , Faïn Xavier , Martinerie Patricia , Etheridge David M. , Lipenkov Vladimir , Barnola Jean-Marc
Published: May 2020

Abstract. In the 1990s, closed and open porosity volumes of firn samples were measured by J.-M. Barnola using the technique of gas pycnometry, on firn from three different polar sites. They are the basis of a parameterization of closed porosity in polar firn, first introduced in Goujon et al. (2003) and used in several firn physics models (e.g., Buizert et al., 2012). However, these data and their processing have not been published in their own right yet. In this short article, we detail how they were processed by J.-M. Barnola and how the closed porosity parameterization was obtained. We show that the original data processing only partially accounts for the presence of reopened bubbles in the samples. Since the proper correction to apply for this effect is hard to estimate, we also processed the data without including a correction for reopened bubbles. Finally, we made these pycnometry data available in order to be used by the glaciology community, notably for the study of polar ice formation and of the composition of gas records in ice cores. They are hosted on the PANGAEA database: https://doi.org/10.1594/PANGAEA.907678 (Fourteau et al., 2019a).
Early instrumental meteorological observations in Switzerland: 1708–1873
Authors: Brugnara Yuri , Pfister Lucas , Villiger Leonie , Rohr Christian , Isotta Francesco Alessandro , Brönnimann Stefan
Published: May 2020

Abstract. We describe a dataset of recently digitised meteorological observations from 40 locations in today's Switzerland, covering the 18th and 19th centuries. Three fundamental variables – temperature, pressure, and precipitation – are provided in a standard format after they have been converted into modern units and quality-controlled. The raw data produced by the digitisation, often including additional variables and annotations, are also provided. Digitisation was performed by manually typing the data from photographs of the original sources, which were in most cases handwritten weather diaries. These observations will be important for studying past climate variability in Central Europe and in the Alps, although the general scarcity of metadata (e.g. detailed information on the instruments and their exposure) implies that some caution is required when using them. The data described in this paper can be found at https://doi.org/10.1594/PANGAEA.909141 (Brugnara, 2020).