bluuebunny/crossref_metadata_2025 huggingface dataset:
Deciphering conserved identical sequences of mature miRNAs among six members of great apes
Authors: Shah Aftab Ali , Ahmad Mushtaq , Ul-Haq Taqweem
Published: August 2018

MicroRNAs (miRNAs) are a group of small RNA molecules which act as negative regulators of gene expression by controlling post-transcriptional regulation through binding to their corresponding mRNAs. Due to their small size, their nucleotide compositions are expected to be similar, but until now, the extent of similarity has not been reported in humans and their six phylogenetically closely related members of hominids. The present study allows direct comparison among six members of hominid species (Homosapiens, Gorillagorilla, Panpaniscus, Pongopygmaeus, Pantroglodytes and Symphalangussyndactylus) in terms of their miRNA repertoire, their evolutionary distance to human, as well as, the categorization of identical species-specific miRNAs. For this purpose, a total of 2694, 370, 157, 673, 590 and 10 mature miRNA sequences of Homosapiens, Gorillagorilla, Panpaniscus, Pongopygmaeus, Pantroglodytes and Symphalangussyndactylus respectively were retrieved from miRbase 22. A total of 12, 4, 4 and 3 conserved clusters with identical miRNA sequences that belong to the same gene families were found in Homosapiens, Gorillagorilla, Pongopygmaeus, Pantroglodytes respectively by neighbor-joining method using MEGA7 software. Interestingly, cross-species comparison has also shown a set of conserved identical miRNA sequences. Homologs of human mature miRNAs with 100% sequence identity are expected to have similar functions in the studied primates. Further in-vitro study is required to investigate common targets for identical miRNAs in the studied primates.
Queer Theory in Education Research
Authors: Jones Tiffany
Published: August 2018

This chapter discusses queer theory definitions and methods. It explores some key queer research study examples in education, including policy research, curriculum and textbook analysis, studies of classroom talk, student surveys and other study types. It provides some key questions that can be used in basic queer reading strategies and linguistics for policy, curriculum and classroom talk analysis; Butler's most well-known concept of performativity; and the potential usefulness of less widely applied concepts including overplay, transference and erasure, as well as other approaches. The chapter finally considers the value of key critiques of queer theory and the way the theory questions the privileging of certain models of time and space, including the Anthropocene age itself.
Anthropocentric Poetry
Authors: McKnight Lucinda
Published: August 2018

This chapter draws on a range of empirical arts-based projects and publications to explore how poetry helps us think about the limitations of human intentionality as curriculum design in the Anthropocene, in spaces of both formal and informal or public learning. The chapter sketches a chronology of arts-based research more broadly, and also specifically in relation to education, and includes examples of the author's widely published research poetry to demonstrate the evolution of this form of inquiry.
An Open Access Model for Quality Scientific Outputs in a Quasi-Linear Information Society
Authors: Omiunu Ojinga Gideon
Published: August 2018

The study provided an open access model for quality scientific outputs in a quasi-linear information society: a pareto optimality approach. The qualitative research method was used and involved a three-stage sampling technique to select participants. The findings of the study revealed that respondents were of the opinion that paying APC or publishing costs constitute burden for authors and that the publishers should have other ways of making profits in business such as library subscription, among others. Thus, all stakeholders should collaborate and be involved in the maintenance of the information society to enhance open access initiatives, especially in developing countries.
Snapshot of the Status Quo of Selected Zimbabwe School Libraries
Authors: Bhebhe Sindiso
Published: August 2018

The aim of this chapter is to discuss the challenges and opportunities faced by selected school libraries in Zimbabwe. It is based on the observation that the school's library system in Zimbabwe, including rural schools, is plagued by a plethora of challenges ranging from neglect in relation to funding and policy issues. It is from this perspective that this chapter seeks to deeply understand and address the challenges and opportunities faced by Zimbabwe's school libraries. The study adopted interpretivism approach and was qualitative in nature. It is a multiple case study with purposively eight schools being selected to be part of the research. Some of the findings noted were that expensive schools mainly frequented by the elites had modern libraries which are manned by qualified librarians with most of them being well remunerated. This was not the case with rural schools in which there were no libraries whilst those with libraries had few outdated and irrelevant books and there were no trained librarians in those schools.
Resonant Compensations in Inductive Wireless Power System
Authors: Reatti Alberto , Kazimierczuk Marian K. , Ayachit Agasthya , Corti Fabio
Published: August 2018

A resonant wireless power system uses capacitors to create resonance between primary and secondary coil at a specific resonant frequency. Thereby, they reduce the reactive power and produce the required transmitted real power over a long range of separation and at higher efficiencies. Depending on the connection between the capacitors and coils, four main topologies can be identified: series-series, series-parallel, parallel-series, and parallel-parallel. In this chapter, these resonance compensations schemes are analyzed, and the advantages and disadvantages of each topology are highlighted.
Control for the Contactless Series Resonant Energy Converter
Authors: Valtchev Stanimir , Valtchev Svilen S.
Published: August 2018

This chapter presents control methods applied in the operation of the series loaded series resonant (SLSR) power converters in a most efficient operation zone. The choice of the control method is affected by the objective to guarantee suitably the efficiency, being this method in the same time, relatively easy to apply. The first part of the chapter compares three basic principles of regulation: frequency mode (FM), pulse width mode (PWM), and their combination (PWM/FM). Finally, a new method for instantaneous regulation is developed. The proposed technique consists of a simplified observation of a state variable value to limit each portion of supplied energy, depending on the requirement for power in each half period. The result of this regulation is comparable to the current mode (CM) control applied to the hard-switching power converters. The viability of this new regulation method is demonstrated by simulations of its analogue circuit implementations and experimentally proved. The circuit is also prepared for the changes in the magnetic coupling (contactless energy transfer).
Research on Modelling Inductive Power Transfer for Electric Vehicles
Authors: Longo Michela , Brenna Morris , Foiadelli Federica
Published: August 2018

The environmental pollution caused by fossil fuels is a hot issue around the world in recent years. The gases lead to poor air quality, in particular in large cities, and the global warming that can cause ecological calamity such as tropical cyclones, heatwaves, drought, and extreme tides. International Energy Agency clearly states that the current energy trend is not sustainable environmentally, economically, and socially. Therefore, it must devise solutions to achieve the future economic growth without adverse environmental effects. The increasing diffusion of electric vehicles is driving academic and institutional research towards exploring different possible ways of charging vehicles in a fast, reliable, and safe way. For this reason, wireless power transfer systems have recently been receiving a lot of attention in the academic literature. This chapter reviews the main analytic and computational tools that are typically used to perform analyses in the context of inductive power transfer systems (IPTSs).
Photochemical Machining
Authors: Wangikar Sandeep Sitaram , Patowari Promod Kumar , Misra Rahul Dev , Misal Nitin Dnyaneshwar
Published: August 2018

The chapter focuses on the history and the development of photochemical machining in brief. The relevant studies related to photochemical machining and parametric effect are also discussed followed by gaps identified along with scope for the work and then the PCM process is explained in detail. The significant control parameters and their effect on the response measures are demonstrated with a fishbone diagram is explored. Further the detailed parametric effect on the response measures along with the scientific explanation of the effect is presented. The chapter is concluded with the two case studies (i.e., PCM of brass and Inconel 718).
Understanding the Effect of Digital Literacy on Employees' Digital Workplace Continuance Intentions and Individual Performance
Authors: Marsh Elizabeth
Published: August 2018

While a growing body of literature suggests that employees' digital skills are important to enable both individuals and organisations to make the most of the digital workplace, empirical understanding of their effect on technology adoption and performance is currently limited. Drawing on prior models of technology acceptance and continuance, the present study investigated the effect of digital literacy on behavioural intention to continue using the digital workplace and, ultimately, on individual performance. Linear regression was used to analyse the conceptual model using survey data from 142 employees of a major UK charitable organisation. Results partially supported the model, demonstrating that employees' digital skills effect continuance intentions and individual performance via their perceptions of ease of use. The findings suggest an important role for digital literacy, both as an antecedent to the more general determinants of technology adoption, and in organisational interventions designed to encourage digital workplace adoption.
Identifying HRM Practices for Improving Information Security Performance
Authors: Kumah Peace , Yaokumah Winfred , Buabeng-Andoh Charles
Published: August 2018

This article focuses on identifying key human resource management (HRM) practices necessary for improving information security performance from the perspective of IT professionals. The Importance-Performance Map Analysis (IPMA) via SmartPLS 3.0 was employed and 232 samples were collected from information technology (IT) professionals in 43 organizations. The analysis identified information security training, background checks and monitoring as very important HRM practices that could improve the performance of organizational information security. In particular, the study found training on mobile devices security and malware; background checks and monitoring of potential, current and former employees as of high importance but with low performance. Thus, these key areas need to be improved with top priority. Conversely, the study found accountability and employee relations as being overly emphasized by the organisations. The findings raised some useful implications and information for HR and IT leaders to consider in future information security strategy.
Independent Learning of Digital Animation
Authors: Yuen May-Chan , Koo Ah-Choo , Woods Peter C.
Published: August 2018

Digital animation (DA) is a field of art and design which requires certain level of design and computer skills with creativity and storytelling. Learners are required to spend a considerable amount of time on their own for practicing the skills after their formal classes. Guided by connectivism and Meyer's factors of independent learning, this article aims at defining independent learning from digital learners' perspective and, identifying factors influencing their moves of independent learning. Twenty digital animation students enrolled at three higher education institutions in Malaysia participated in focus group discussions (FGD). Overall thematic analysis revealed that the students' perspective of independent learning corroborated with most student-centred learning concepts. The digital learners were highly dependent on the Internet for their learning; the students however struggled in their pursuit of becoming an independent learner due to fear of failure (or kiasuism), and self-criticism.
Demand Biorhythm Estimation for Setting Service Capacity
Authors: Cohen Yuval , Rozenes Shai
Published: August 2018

This article is based on an analysis of empirical data on various service demand patterns such as electricity and water consumption, banks, hospitals, communications and others. The research findings show similar patterns of demand for various different services in different parts of the world. The patterns reflect the relevant population's level of activity. Daytime services have typical peak hours during a workday. This is nicely explained by what the authors call the ‘Demand Biorhythm.' Many daytime services experience a double hump demand, whereas in the US the service demand may also have a single hump. The analysis shows a striking demand similarity of the same weekdays, and a significant difference between the demand of workdays and weekend days. Also, the first day of the week always experiences a demand surge. The article discusses ways to efficiently plan the service workforce and capacity based on the relevant demand patterns.
Impact of the PMOs' Roles on Project Performance
Authors: Otra-Aho Ville Juhani , Arndt Christian , Bergman Jukka-Pekka , Hallikas Jukka , Kaaja Jouko
Published: August 2018

Organizations increasingly often set up project management offices (PMOs) in order to overcome the challenges of increased complexity and importance of projects, and thereby create value, but evidence for value creation, such as improved project performance, has remained scarce. This paper uses a sample of Finnish firms in order to evaluate the impact of PMO roles and processes on project performance. Using factor analysis and regressions, the authors show that the PMO's coordinator and trainer processes have a positive association with project performance. However, a PMO in the role of a strategy manager has a negative impact on project performance.
Identification and Analysis of Project Management Success Factors in Information Technology SMEs
Authors: Correa Juan Andrés González , Castañeda Sandra Liliana Sánchez , Quintero Deisy Aydee Velandia , Giraldo Germán Eduardo
Published: August 2018

This article identifies and analyses the success factors involved in project management through an exploratory study that encompasses nineteen interviews, fifty-seven surveys and one session with a focus group of project managers, department managers who have taken the role of project managers and general managers of small and medium-sized enterprises (SMEs) of the information technology (IT) sector in Bogota, Colombia. After analyzing the information, the authors identified eleven factors for the achievement of project management goals in these organizations. These comprise managerial, organizational and sector aspects that influence the resource management and leadership in projects of SMEs of information technology.
Exploring the Determinants of Organizational Resilience in Islamic Banks
Authors: Alrob Mohamed Mahmoud Abo , Jaaron Ayham A. M.
Published: August 2018

Resilience has been viewed as the critical component behind Islamic banking organizations' ability to respond and compete during crisis. However, there seems to be scarcity of empirical attempts to explore the determinants of stronger resilience in Islamic banking organizations. This article is an attempt to develop a managerial framework of Islamic banking organizations that identifies these determinants of improved resilience. Two case studies were conducted in two Islamic banks in Palestine. Data were collected via semi-structured interviews, observations, and archival documents, followed by the use of the Resilience Benchmark Tool (RBT). Cross-case analysis of the results shows that organizational resilience in banking organizations is characterized by two dimensional determinants for improving organizational resilience; planning and adaptive capacity along with a set of ten resilience enhancing factors. The article demonstrates important dynamics of how resilient capabilities can be incorporated into the managerial models of banking organizations during turmoil.
Auditing an Agile Development Operations Ecosystem
Authors: Subramanian Aishwarya , Krishnamachariar Priyadarsini Kannan , Gupta Manish , Sharman Raj
Published: August 2018

In an enterprise software development, DevOps is a practice of integrating development and operations to deliver cost-efficient, improved quality solutions to the customer by automating the existing processes to achieve “continuous delivery.” In the current dynamic IT Ecosystem where there is a rising need to prove a competitive edge to maximize profitability, it is pivotal to drive business value with profound emphasis on quality. Agile enables us to take calculated risks during development whereas its affinity to adopting DevOps will promote continuous delivery with reduced friction to improve business efficiency. As this approach requires a change in people, process, technology, culture, usage of right tools and techniques, the early involvement of IT Auditors during the process of transformation could aid to build effective Risk Management strategies to handle organizational challenges. This article aims to present a risk-based audit approach to effectively use audit tools and techniques in an Agile-DevOps transformation environment to achieve maximum business value.
Management of Delia (Diptera: Anthomyiidae) through selectively timed planting of Phaseolus vulgaris (Fabaceae) in Atlantic Canada
Authors: Silver Natalie , Hillier Kirk , Blatt Suzanne
Published: August 2018

Delia Robineau-Desvoidy (Diptera: Anthomyiidae), including Delia platura (Meigen), are known pests of vegetable crops. Here, three studies were conducted to examine the relationship between Delia species and Phaseolus vulgaris Linnaeus (Fabaceae). Field studies documented a relationship between planting date and occurrence of Delia damage on P. vulgaris. Plantings in mid-June resulted in higher crop yields (mean bean pods per plant) and reduced damage ratings compared with earlier plantings. Late-May and early-June planting dates were not favourable, as they resulted in high damage ratings and low plant survival. Late-June and July plantings resulted in low damage ratings but low crops yields. Growth chamber experiments examined oviposition preference of D. platura females at eight phenological stages for two varieties of P. vulgaris. Results indicated significantly higher oviposition rates on bean plants at early phenological growth stages, with no significant varietal preference shown by maggots. Laboratory experiments quantified the impact of D. platura larval infestation on two P. vulgaris varieties at two growth stages. Results indicated no significant difference in variety choice. Recommendation for planting P. vulgaris to coincide with Delia phenology using a degree-day model is discussed.
The Canonical but Not the Noncanonical Wnt Pathway Inhibits the Development of Allergic Airway Disease
Authors: Beckert Hendrik , Meyer-Martin Helen , Buhl Roland , Taube Christian , Reuter Sebastian
Published: August 2018

Asthma is a syndrome with multifactorial causes, resulting in a variety of different phenotypes. Current treatment options are not curative and are sometimes ineffective in certain disease phenotypes. Therefore, novel therapeutic approaches are required. Recent findings have shown that activation of the canonical Wnt signaling pathway suppresses the development of allergic airway disease. In contrast, the effect of the noncanonical Wnt signaling pathway activation on allergic airway disease is not well described. The aim of this study was to validate the therapeutic effectiveness of Wnt-1–driven canonical Wnt signaling compared with Wnt-5a–driven noncanonical signaling in murine models. In vitro, both ligands were capable of attenuating allergen-specific T cell activation in a dendritic cell–dependent manner. In addition, the therapeutic effects of Wnt ligands were assessed in two different models of allergic airway disease. Application of Wnt-1 resulted in suppression of airway inflammation as well as airway hyperresponsiveness and mucus production. In contrast, administration of Wnt-5a was less effective in reducing airway inflammation or goblet cell metaplasia. These results suggest an immune modulating function for canonical as well as noncanonical Wnt signaling, but canonical Wnt pathway activation appears to be more effective in suppressing allergic airway disease than noncanonical Wnt activation.
Graphical tool for assessing the critical temperatures of steel beams and columns in fire
Authors: Pignatta Silva Valdir , Ribeiro Melão Arthur , Pierin Igor
Published: August 2018

In a fire situation, the temperature in which the ultimate limit state of the structural element is reached is called critical temperature. It is very laborious to determine it. The aim of this work was to create a graphical tool to allow quick determination of the critical temperature of I shaped columns and beams without local buckling. The method used was based on the Brazilian standard and using AcoInc software developed by the authors. The result was a tool whose similarity was not found in the literature. The use of the tool developed in this study simplifies the use of the standardized design method. One conclusion to be highlighted is one in which constants values of the critical temperature, generally accepted in practice, may be unsafe.
Measurement properties of the construct of the code of ethics content: The South African experience
Authors: Mpinganjira Mercy , Roberts-Lombard Mornay , Svensson Goran , Wood Greg
Published: August 2018

Background: Many organisations develop codes of ethics to help guide business conduct. However, not much is known about the contents of codes of ethics. Objectives: This article aims at investigating the code of ethics content construct and its measurement properties using a sample of firms from South Africa. Method: The study followed a quantitative research approach. The sampling frame consisted of the top 500 companies in South Africa. A structured questionnaire was administered using the telephone survey method. The respondents consisted of company secretaries and heads or managers responsible for ethics in the respective companies. At the end of the data collection period, a total of 222 usable responses were obtained. Results: The findings show that South African top companies have comprehensive codes of ethics as evidenced by the high mean values obtained from all of the content items under investigation. The findings also support the notion that the code of ethics content construct is multidimensional. Seven different dimensions were confirmed in the analysis. The measurement model of the ethics content construct was found to be valid as evidenced by the goodness-of-fit measure and measures of validity. Conclusion: The study shows that the code of ethics construct is multi-dimensional in nature. The framework provided in this study can also be used in developing, evaluating and strengthening existing codes where such need arises. This study contributes to theory on business ethics and presents the first tested measurement model of the code of ethics construct in South Africa.
The combined influence of self-leadership and locus of control on the job performance of engineering workforce in a power generation utility: An empirical perspective
Authors: Rambe Patient , Modise Disebo L. , Chipunza Crispen
Published: August 2018

Orientation: The joint effects of self-leadership and locus of control within an engineering context have been under-explored because much research focused on self-leadership and locus of control as independent concepts, and studies on their combined effects on organisational performance remain hard to encounter in emerging economies.Research purpose: The aim of the study was to develop deeper empirical knowledge of the combined effects of self-leadership and locus of control on job performance of engineering workforce in Eskom Free State.Motivation for the study: The originality of the study lies in the reconstitution of individual self-leadership and locus of control concepts as they relate to job performance and its impact on prospective engineers who work at Eskom in Bloemfontein.Research approach/design and method: Drawing on a quantitative approach, a survey was conducted on 134 engineering personnel (comprising engineers, technologists and technicians). Of this workforce, a total of 107 engineers participated in the study representing a response rate of 79.8%. Correlation and multiple regression analysis were used to analyse the corpus of quantitative data.Main findings: The results demonstrate that self-leadership and locus of control are significant independent variables and when considered jointly, they have a positive significant impact on job performance of the Eskom engineering workforce.Practical/managerial implications: Implications for the initiation and fostering of self-leadership and locus of control to improve the job performance of Eskom Bloemfontein engineering workforce are discussed.Contribution/value-add: The study contributes to engineers’ task-focused behaviour through its expectations for the engineering workforce to be self-leaders who exercise internal locus of control in the execution of their jobs. This study also contributes to engineers’ work-related personality dimensions and sense of self-awareness through an exposition of individual personalities they were not conscious of.
Dispersal traits in the hyper-arid hot desert of the United Arab Emirates
Authors: Shabana Hatem A. , Navarro Teresa , El-Keblawy Ali
Published: August 2018

Background and aims – This study describes the dispersal traits of 302 species in five Afro-Arabian habitats from the hyper-arid hot desert of United Arabian Emirates (UAE).Methods – Diaspore size (diaspora length) was studied in relation to growth forms, dispersal modes, presence of structures for long distance dispersal, APG IV groups, phytogeography and dispersal phenology using ANOVA and Pearson χ2 test-statistical analyses.Results – Small diaspores were predominant (six orders of magnitude from 10-4 to 102). The major diaspores were found in Fabids phylogenetic APG IV group (1.80±0.41 cm) mainly trees and the minor in Commelinids (0.30±0.08 cm). The most dominant dispersal mode was semachory (43.7% of the total and 67.5% of the herbaceous species), followed by anemo-meteochory (28.8%) and barochory (23.8%). Semachores/barochores (67.5%) formed the largest groups from the Fabaceae, Poaceae, Boraginaceae, Brassicaceae and Amaranthaceae families. Savanna trees such as Acacia, Prosopis, Ziziphus sp. and Indigofera sp. produced large diaspores secondarily dispersed by vertebrates. Anemo-meteochoric species with small diaspores were predominantly semi-shrubs such as Haloxylon sp. Graminoids such as Stipa sp. and Stipagrostis sp., without structures for long-distance dispersal had diaspore appendages acted as “active drills” in soil cracks. Dryness (dry season) favours the efficient dispersion by the wind for the small shrub species with haired capsule (e.g. Aerva javanica), winged calyx (e.g. Astragalus squarrosus) or wings (e.g. Tribulus qatarensis). Most of the species studied (64.2%) dispersed in the dry season according to what was found in other arid region from the world. The longer dispersal phenology corresponded to Saharo-Arabian and Sudano-Decanian species which is related to the floristic richness of the study area. Species dispersal throughout the year indicates an important seed resource e.g. barochoric species with fleshy fruits or pods with nutrient structures (e.g. Senna italica and Indigofera sp.).Conclusions – In the hyper-arid hot desert of UAE, the dispersal spectra are close to those recorded in other arid environments but with particularities due to the presence of African floristic elements.
Amanita dulciodora (Amanitaceae, Basidiomycota), a striking new species of Amanita section Lepidella from Northeast Brazil
Authors: Nascimento Cristiano C. , Sá Mariana C.A. , Bezerra José Luiz , Wartchow Felipe
Published: August 2018

Background – Amanita Pers. has a worldwide distribution and is one of the most well-known fungal genera in terms of both morphotaxonomy and molecular phylogenetics, consisting of many edible, as well as poisonous, even lethal, mushrooms. The genus is also known to form ectomycorrhizal associations with angiosperms and gymnosperms and play an important role in ecosystems. Although previous studies have already pointed out the high diversity of the genus Amanita in tropical areas, only a few recent studies continue to record and/or describe new species of Amanita from Brazilian territory. Herein, an additional, morphologically striking new species of Amanita sect. Lepidella is described from Northeast Brazil.Methods – The new species was collected at ‘Parque Estadual Serra do Conduru’ (PESC), located in the municipalities of Uruçuca, Itacaré e Ilhéus, Bahia state. The park is an Atlantic Forest protected area with about 7000 ha in a region with a high degree of endemism. For morphological analysis, standard methods for Amanita were followed.Key results – Amanita dulciodora is described as new species from Atlantic Forest remnants in southeast Bahia. It is assignable to Amanita stirps Crassiconus within Amanita subsect. Solitariae and is mainly characterized by its (1) medium-size basidiomata with cap colour and appearance dominated by universal veil at first; (2) distinctly coloured acute-pyramidal, truncate-pyramydal to verrucose warts which are mainly composed of irregularly disposed, ovoid to subglobose to clavate cells intermixed with very abundant filamentous hyphae; (3) mostly ellipsoid to elongate amyloid basidiospores and (4) the common presence of clamps at the basal septa of basidia. It was compared with its similar species, A. crassiconus and illustrated with line drawings and photographs.
The genus Cola (Malvaceae) in Cameroon’s Korup National Park, with two novelties
Authors: Kenfack David , Sainge Moses N. , Chuyong George B. , Thomas Duncan W.
Published: August 2018

Background and aims – Cola, the second largest genus of the Malvaceae-Sterculioideae comprises 100–135 small to large tree species confined in nature to African forests, though cultivated elsewhere. Current species distribution ranges show that the genus is highly diverse in the seasonally wet forests along the Nigeria-Cameroon border, including the Korup National Park (KNP). In this paper we examine the diversity and abundance of Cola in KNP compared to other forests for which comparable data are available. We also describe two novelties in the genus.Methods – We used inventory data from a 50-ha permanent plot in southern KNP where all Cola trees and saplings down to 1 cm in diameter were tagged, mapped and identified. Additional collections of the genus came from the 11 km trail leading to the plot. Classic herbarium techniques and field observations were used for the morphological identification and description of specimens at MO and YA and from our personal collections. Cola species richness and abundance was estimated from the plot data and compared to other African forest sites for which comparable data are available. The evaluation of the conservation status of the two new species described in this paper followed the IUCN Red List Categories and Criteria. Key results – Twenty-five species of Cola were identified in the southern part of the KNP, including four undescribed species, raising the total number of Cola species in Cameroon to 46. The abundance of the genus in KNP was three orders of magnitude higher than in the Rabi forest in southwestern Gabon or in the Ituri forest in eastern D.R. Congo. This high species richness and abundance suggests that KNP is part of the center of diversity of the genus. Two new species, Cola zemagoana Kenfack & D.W.Thomas and C. mamboana Kenfack & Sainge are described and illustrated. Both species are only known from the lowland rainforest of southwestern Cameroon. Cola zemagoana is narrow endemic of southern KNP and its conservation status is assessed as Endangered. Cola mamboana is confined to the lowland forests of southwestern Cameroon, is locally very abundant in protected areas and is also assigned the conservation status Endangered.
A comparison of posterior atmospheric CO2 adjustments obtained from in situ and GOSAT constrained flux inversions
Authors: Polavarapu Saroja M. , Deng Feng , Byrne Brendan , Jones Dylan B. A. , Neish Michael
Published: August 2018

Abstract. Posterior fluxes obtained from inverse modelling are difficult to verify because there is no dense network of flux measurements available to evaluate estimates against. Here we present a new diagnostic to evaluate structures in posterior fluxes. First, we simulate the change in atmospheric CO2 fields between posterior and prior fluxes, referred to as the posterior atmospheric adjustments due to updated fluxes (PAAFs). Second, we calculate the uncertainty in atmospheric CO2 fields due solely to uncertainty in the meteorological fields, referred to as the posterior atmospheric adjustments due to imperfect meteorology (PAAMs). We argue that PAAF can only be considered robust if it exceeds PAAM, that is, the changes in atmospheric CO2 between the posterior and prior fluxes should at least exceed atmospheric CO2 changes arising from imperfect meteorology. This diagnostic is applied to two CO2 flux inversions: one which assimilates observations from the in situ CO2 network and the other which assimilates observations from the Greenhouse Gases Observing SATellite (GOSAT). On the global scale, PAAF in the troposphere reflects northern extratropical fluxes, whereas stratospheric adjustments primarily reflect tropical fluxes. In general, larger spatiotemporal variations in PAAF are obtained for the GOSAT inversion than for the in situ inversion. Zonal standard deviations of the PAAF exceed the PAAM through most of the year when GOSAT observations are used, but the minimum value is exceeded only in boreal summer when in situ observations are used. Zonal spatial structures in GOSAT-based PAAF exceed PAAM throughout the year in the tropics and through most of the year in the northern extratropics, suggesting GOSAT flux inversions can constrain zonal asymmetries in fluxes. However, we cannot discount the possibility that these structures are influenced by biases in GOSAT retrievals. Verification of such spatial structures will require a dense network of independent observations. Because PAAF depends on the choice of prior fluxes, the comparison with PAAM is system dependent and thus can be used to monitor a given assimilation system's behaviour.
Measurement and modeling of the multiwavelength optical properties of uncoated flame-generated soot
Authors: Forestieri Sara D. , Helgestad Taylor M. , Lambe Andrew T. , Renbaum-Wolff Lindsay , Lack Daniel A. , Massoli Paola , Cross Eben S. , Dubey Manvendra K. , Mazzoleni Claudio , Olfert Jason S. , Sedlacek III Arthur J. , Freedman Andrew , Davidovits Paul , Onasch Timothy B. , Cappa Christopher D.
Published: August 2018

Abstract. Optical properties of flame-generated black carbon (BC) containing soot
particles were quantified at multiple wavelengths for particles produced
using two different flames: a methane diffusion flame and an ethylene
premixed flame. Measurements were made for (i) nascent soot particles,
(ii) thermally denuded nascent particles, and (iii) particles that were
coated and then thermally denuded, leading to the collapse of the initially
lacy, fractal-like morphology. The measured mass absorption coefficients
(MACs) depended on soot maturity and generation but were similar between
flames for similar conditions. For mature soot, here corresponding to
particles with volume-equivalent diameters >∼160 nm, the MAC and
absorption Ångström exponent (AAE) values were independent of
particle collapse while the single-scatter albedo increased. The MAC values
for these larger particles were also size-independent. The mean MAC value at
532 nm for larger particles was 9.1±1.1 m2 g−1, about
17 % higher than that recommended by Bond and Bergstrom (2006), and the
AAE was close to unity. Effective, theory-specific complex refractive index
(RI) values are derived from the observations with two widely used methods:
Lorenz–Mie theory and the Rayleigh–Debye–Gans (RDG) approximation. Mie
theory systematically underpredicts the observed absorption cross sections at
all wavelengths for larger particles (with x>0.9) independent of the
complex RI used, while RDG provides good agreement. (The dimensionless size
parameter x=πdp/λ, where dp is particle
diameter and λ is wavelength.) Importantly, this implies that the
use of Mie theory within air quality and climate models, as is common, likely
leads to underpredictions in the absorption by BC, with the extent of
underprediction depending on the assumed BC size distribution and complex RI
used. We suggest that it is more appropriate to assume a constant,
size-independent (but wavelength-specific) MAC to represent absorption by
uncoated BC particles within models.
Saharan dust and biomass burning aerosols during ex-hurricane Ophelia: validation of the new UK lidar and sun-photometer network
Authors: Osborne Martin , Adam Mariana , Buxmann Joelle , Sugier Jaqueline , Marenco Franco , Haywood Jim
Published: August 2018

Abstract. On 15–16 October 2017, ex-hurricane Ophelia passed to the West of the British Isles, bringing dust from the Sahara and smoke from Portuguese forest fires that was observable to the naked eye and reported in the national press. We report here detailed observations of this event using the UK operational lidar and sun-photometer network, established for the early detection of aviation hazards. The observations, taken continuously over a period of 30 hours, show a complex picture, dominated by several aerosol layers at different times, and clearly correlated with the passage of different air-masses associated with the intense cyclonic system. A similar evolution was observed at several sites, with a time delay between them explained by their different location with respect to the storm. The event commenced with a hallow dust layer at 1–2 km in altitude, and culminated in a deep and complex structure that lasted 12 hours at each site, correlated with the storm’s warm sector. For most of the time, the aerosol detected as mineral dust, as highlighted by depolarisation measurements, but an intense smoke layer was observed towards the end of the event, lasting around 3 hours at each site. The aerosol optical depth AOD) during the whole event ranged from 0.2 to 2.9, with the larger AOD correlated to the intense smoke plume. Such a large AOD is unprecedented in the United Kingdom according to AERONET records or the last 20 years. The Raman lidars permitted the measurement of the aerosol extinction coefficient at 355 nm, the particle depolarisation ratio (PDR) and the lidar ratio (LR), and made possible the separation of the dust (depolarising) aerosol from other aerosol types. A specific extinction has also been computed to provide an estimate of the atmospheric concentration of both aerosols separately, which peaked at 500 ± 100 μg m−3 for the dust and 600 ± 100 μg m−3 for the smoke. Back-trajectories computed using the Numerical Atmospheric dispersion Modelling Environment (NAME) were used to identify the sources and strengthen the conclusions drawn from the observations. The UK network represents a significant expansion of the observing capability in Northern Europe, with instruments evenly distributed across Great Britain, from Camborne in Cornwall to Lerwick in the Shetland Islands, and this study represents the first attempt to demonstrate its capability and validate the methods in use. Its ultimate purpose will be the detection and quantification of volcanic plumes, but the present study clearly demonstrates the advanced capabilities of the network.
A preliminary stochastic analysis of the uncertainty of natural processes related to renewable energy resources
Authors: Klousakou Elli , Chalakatevaki Maria , Dimitriadis Panayiotis , Iliopoulou Theano , Ioannidis Romanos , Karakatsanis Georgios , Efstratiadis Andreas , Mamasis Nikos , Tomani Romina , Chardavellas Efthimis , Koutsoyiannis Demetris
Published: August 2018

Abstract. The ever-increasing energy demand has led to overexploitation of fossil fuels
deposits, while renewables offer a viable alternative. Since renewable energy
resources derive from phenomena related to either atmospheric or geophysical
processes, unpredictability is inherent to renewable energy systems. An
innovative and simple stochastic tool, the climacogram, was chosen to explore
the degree of unpredictability. By applying the climacogram across the
related timeseries and spatial-series it was feasible to identify the degree
of unpredictability in each process through the Hurst parameter, an index
that quantifies the level of uncertainty. All examined processes display a
Hurst parameter larger than 0.5, indicating increased uncertainty on the long
term. This implies that only through stochastic analysis may renewable energy
resources be reliably manageable and cost efficient. In this context, a pilot
application of a hybrid renewable energy system in the Greek island of
Astypalaia is discussed, for which we show how the uncertainty (in terms of
variability) of the input hydrometeorological processes alters the
uncertainty of the output energy values.
Unraveling hydrometeor mixtures in polarimetric radar measurements
Authors: Besic Nikola , Gehring Josué , Praz Christophe , Figueras i Ventura Jordi , Grazioli Jacopo , Gabella Marco , Germann Urs , Berne Alexis
Published: August 2018

Abstract. Radar-based hydrometeor classification typically comes down
to determining the dominant type of hydrometeor populating a given radar
sampling volume. In this paper we address the subsequent problem of inferring
the secondary hydrometeor types present in a volume – the issue of
hydrometeor de-mixing. The present study relies on the semi-supervised
hydrometeor classification proposed by Besic et al. (2016) but nevertheless
results in solutions and conclusions of a more general character and
applicability. In the first part, oriented towards synthesis, a bin-based
de-mixing approach is proposed, inspired by the conventional coherent and
linear decomposition methods widely employed across different remote-sensing
disciplines. Intrinsically related to the concept of entropy, introduced in
the context of the radar hydrometeor classification in Besic et al. (2016), the
proposed method, based on the hypothesis of the reduced random interferences
of backscattered signals, estimates the proportions of different hydrometeor
types in a given radar sampling volume, without considering the neighboring
spatial context. Plausibility and performances of the method are evaluated
using C- and X-band radar measurements, compared with hydrometeor properties
derived from a Multi-Angle Snowflake Camera instrument. In the second part,
we examine the influence of the potential residual random interference
contribution in the backscattering from different hydrometeors populating a
radar sampling volume. This part consists in adapting and testing the
techniques commonly used in conventional incoherent decomposition methods to
the context of weather radar polarimetry. The impact of the residual
incoherency is found to be limited, justifying the hypothesis of the reduced
random interferences even in a case of mixed volumes and confirming the
applicability of the proposed bin-based approach, which essentially relies on
first-order statistics.
Modeling rhizosphere carbon and nitrogen cycling in Eucalyptus plantation soil
Authors: Valadares Rafael Vasconcelos , Neves Júlio César Lima , Costa Maurício Dutra , Smethurst Philip James , Peternelli Luiz Alexandre , Jesus Guilherme Luiz , Cantarutti Reinaldo Bertola , Silva Ivo Ribeiro
Published: August 2018

Abstract. Vigorous Eucalyptus plantations produce 105 to
106 km ha−1 of fine roots that probably increase carbon (C) and
nitrogen (N) cycling in rhizosphere soil. However, the quantitative
importance of rhizosphere priming is still unknown for most ecosystems,
including these plantations. Therefore, the objective of this work was to
propose and evaluate a mechanistic model for the prediction of rhizosphere C
and N cycling in Eucalyptus plantations. The potential importance of
the priming effect was estimated for a typical Eucalyptus plantation
in Brazil. The process-based model (ForPRAN – Forest Plantation Rhizosphere
Available Nitrogen) predicts the change in rhizosphere C and N cycling
resulting from root growth and consists of two modules: (1) fine-root growth
and (2) C and N rhizosphere cycling. The model describes a series of soil
biological processes: root growth, rhizodeposition, microbial uptake,
enzymatic synthesis, depolymerization of soil organic matter, microbial
respiration, N mineralization, N immobilization, microbial death, microbial
emigration and immigration, and soil organic matter (SOM) formation. Model
performance was quantitatively and qualitatively satisfactory when compared
to observed data in the literature. Input variables with the most influence
on rhizosphere N mineralization were (in order of decreasing
importance) root diameter > rhizosphere thickness > soil temperature > clay
concentration. The priming effect in a typical Eucalyptus plantation
producing 42 m3 ha−1 yr−1 of shoot biomass, with assumed
losses of 40 % of total N mineralized, was estimated to be 24.6 % of
plantation N demand (shoot + roots + litter). The rhizosphere cycling
model should be considered for adaptation to other forestry and agricultural
production models where the inclusion of such processes offers the potential
for improved model performance.