bluuebunny/crossref_metadata_2025 huggingface dataset:
Ethical Theory and Its Application Teaching Marginalized Populations
Authors: McCray Carissa
Published: April 2019

This chapter discusses deontological, rights, utilitarian, and virtues ethical theories by analyzing the ethical theories in diverse occupations. Within the background of each ethical theory, a discussion of the historical, social, and personal provides information and characteristics of the theory. Finally, there is a discussion on how the various ethical theories can be applied to marginalized populations to ensure an environment that supports learning and diversity. In maintaining a socially, cultural, and economically sound environment, honest and transparent discussions, professional development, and truthful evaluations should occur to begin cycles anew. As these various ethical theories are implemented, a strong work ethic is required. The implication of these theories is to provide an atmosphere that is equitable, encourages learning, and protects and respects the humanity of others.
Standing Against the Wind
Authors: Blankenship Rebecca J.
Published: April 2019

In the wake of an increasingly divisive sociopolitical climate in the United States, there is a sense of immediate urgency among institutions of higher education to speak with a united voice in terms of maintaining the post-civil rights era principles of providing equitable access to educational opportunities for all students. Students, regardless of their race, ethnicity, gender, gender identity, religion, or socioeconomic status should be afforded equal access to sound educational opportunities. Thusly, the next generation of teachers must be not only instructionally competent in their grade or subject area but also be capable of adapting that instruction to meet the sociocultural and socioemotional needs of the students they serve. From this charge, a larger conversation emerges calling for a change in the existing narrative related to teaching marginalized populations away from political banter towards the release of silent voices that have the agentic potential to engage as voices of authentic change.
Ensemble Learning Mechanisms for Threat Detection
Authors: Arul Rajakumar , Moorthy Rajalakshmi Shenbaga , Bashir Ali Kashif
Published: April 2019

Technology evolution in the network security space has been through many dramatic changes recently. Enhancements in the field of telecommunication systems invite fruitful security solutions to address various threats that arise due to the exponential growth in the number of users. It's crucial for upgrading the entire infrastructure to safeguard the system from specific threats. So, there is a huge demand for the learning mechanism to realize the behavior of attacks. Recent upcoming technologies like machine learning and deep learning can support in the process of learning the behavior of all types of attacks irrespective of their deployment criteria. In this chapter, the analysis of various machine learning algorithms with respect to a few scenarios that can be adopted for the benefits of improving the security standard of the network. This chapter briefly discusses various know attacks and their classification and how machine learning algorithms can be involved to overcome the popular attacks. Also, various intrusion detection and prevention schemes were discussed in detail.
The Criteria of Websites Quality on Consumers' Buying Behavior
Authors: Vatansever Kemal , Öztemiz Hatice Handan
Published: April 2019

The aim of this chapter is to investigate the effects of website quality criteria that affect the customer purchasing intentions. Website quality criteria are categorized as security, privacy, usability and web design, convenience, trust and confidence, product value, and product customization. In this study, the criteria are chosen in accordance with the two main criteria of the technology acceptance model. In this chapter, Decision-Making Trial and Evaluation Laboratory (DEMATEL) is used to evaluate the effects of criteria on each other from a causal perspective. According to the research findings, security, trust and trustworthiness, product value, and product customization criteria are more effective than privacy, usability, and web design convenience criteria.
Website Evaluation Using Interval Type-2 Fuzzy-Number-Based TOPSIS Approach
Authors: Efe Burak
Published: April 2019

In recent years, with the development of the internet, there has been an increase in interest in the internet thanks to other technological developments. In the face of increased user demand, educational institution websites have to maintain high quality of service for a sustainable success. The authors present the possibility degree based TOPSIS method with IT2F numbers as an extension of TOPSIS method to evaluate the educational institution websites. In contrast to precise numbers in TOPSIS method, the merit of fuzzy TOPSIS method is to handle the fuzzy numbers to evaluate the alternatives. Type-1 fuzzy numbers consider crisp membership degrees to express fuzzy numbers but IT2F numbers handle more uncertainties than type-1 fuzzy numbers. The subjective judgments of the decision makers are aggregated by using the IT2F number operations to determine the weights of these criteria. IT2TrF numbers-based TOPSIS phase is employed to rank alternatives based on criteria so that assessment process is completed. The proposed method is applied to evaluate the educational institution websites.
The Popular Culture of 3D Printing
Authors: Novak James I. , Bardini Paul
Published: April 2019

As 3D printing technology achieves mainstream adoption, people are forming new relationships with products as they shift from passive consumers to “prosumers” capable of both producing and consuming objects on demand. This is fueled by expanding online 3D printing communities, with new data within this chapter suggesting that prosumers are challenging existing understandings of popular culture as they bypass traditional mass manufacturing. With 3D digital files rapidly distributed through online platforms, this chapter argues that a new trend for “viral objects” is emerging, alongside the “3D selfie,” as digital bits spread via the internet are given physical form through 3D printing in ever increasing quantities. Analysis of these trends will provide academics, educators, and prosumers with a new perspective of 3D printing's socio-cultural impact, and further research directions are suggested to build a broader discourse around the opportunities and challenges of a cyberphysical future.
Computer-Assisted Synonymous Phrase Learning
Authors: Chen Mei-Hua
Published: April 2019

It is not uncommon to see lists of semantically equivalent phrases in pedagogical materials. However, empirical investigations of the effect of synonymous phrase learning on vocabulary development are rarely attempted. The current study promotes computer-assisted synonymous phrase learning by introducing PREFER, a corpus-based paraphrasing system. The organized information including synonymous phrases, Chinese translations, usage patterns, and example sentences would help EFL learners develop vocabulary knowledge in terms of form, meaning, and use. The performances of 49 EFL first-year college students were evaluated using a 15-set multi-select test. The results showed that students consulting PREFER made greater progress than those consulting existing online tools. The improvements of the less proficient students were especially significant, which was to be expected. More importantly, the analyses of learners' errors indicated that their learning difficulties primarily resulted from the lack of attention to word form and the function words (i.e., word form and use) while learning vocabulary.
Using Machinima as Teaching and Learning Materials
Authors: Shrestha Sagun , Harrison Tilly
Published: April 2019

Machinima, screencast animated videos made in a virtual world, are still not a very well-known phenomenon, and there has been little reseach in relation to their use as a teaching material in English language classrooms. This study aimed to investigate the potential for and challenges in using machinima in the pre-intermediate English as a foreign language (EFL) classroom. Bespoke machinima were created for three classes in Nepal, and the lessons using them were observed. Two teachers and four students were given semi-structued interviews, and 20 students were asked to write a reflective note on their impression of the use of machinima. The findings of the study indicate that machinima are distinct from other materials in that they can be contextualized to address the needs, interests, and values of the learners. Student engagement is thus found to have been significantly higher.
Developing and Evaluating a Learner-Friendly Collocation System With User Query Data
Authors: Wu Shaoqun , Fitzgerald Alannah , Yu Alex , Witten Ian
Published: April 2019

Learning collocations is one of the most challenging aspects of language learning as there are literally hundreds of thousands of possibilities for combining words. Corpus consultation with concordancers has been recognized in the literature as an established way for language learners to study and explore collocations at their own pace and in their own time although not without technological and sometimes cost barriers. This paper describes the development and evaluation of a learner-friendly collocation consultation system called FlaxLC in a design departure away from the traditional concordancer interface. Two evaluation studies were conducted to assess the learner-friendliness of the system: a face-to-face user study to find out how international students in a New Zealand university used the system to collect collocations of their own interest and a user query analysis—based on an observable artefact of how online learners actually used the system over the course of one year—to examine how the system is used in real life to search and retrieve collocations.
Playfulness in Online Marketing
Authors: Vuorela Taina , Alatalo Sari , Oikarinen Eeva-Liisa
Published: April 2019

This article explores different challenges and opportunities of using humour and playfulness in online marketing. Humour has been investigated intensively in marketing, especially in advertising, yet there is little knowledge of the challenges and opportunities in online marketing faced by practitioners. This study analyses key studies conducted in the context of a unique case: a Finnish research project exploring humour as a strategic tool for companies. These studies can provide emerging insights of humour in online marketing which are relevant for practitioners: humour as a transformational appeal, individual differences related to humour appreciation, role of storytelling and playfulness in blogging and challenges related to use of humour such as credibility.
Management Game
Authors: Kesti Marko , Ylitalo Aino-Inkeri , Vakkala Hanna
Published: April 2019

Digital disruption and continuous productivity improvement require more from people management, thus raising the bar for leadership competencies. International studies indicate that leadership competence gaps are large and traditional leadership training methods does not seem to solve this problem. This article's findings supports this situation. The authors will open the complexity behind organizational productivity development and present game theoretical architecture that simulates management behavior effects to human performance. New methods enable practice-based learning that enables formatting leaders' behavior so that it will create long-term success with continuous change. The authors will present gamified leadership training procedure and discuss the practical learning experiences from a management simulation game. The authors' study reveals challenges at interactive leadership skills, thus, it is argued, that there seems to be problems at the leadership mind-set. Therefore, more sophisticated learning methods and tools should be used.
Coupling Coordination of Internet Development, Technology Innovation and Star Hotel Efficiency
Authors: Ruan Wenqi , Li Yongquan
Published: April 2019

The research on the relationship between the three systems of internet development, technology innovation and star hotel efficiency for the development of the regional hotel industry provides a reference for this article. Based on the coupled coordination model, the authors analyze the evolutionary relationship between the three systems using the spatiotemporal dimension. The study draws the following conclusions. (1) In the 31 Chinese provinces examined, internet development and technological innovation have a high relevance, and there is a trend in these systems of decline from east to west in the three-ladder distribution. (2) The development trend of star hotel efficiency first rose and then fell, which shows its susceptibility to national policy. The spatial pattern reflects high efficiency in eastern and western China and low efficiency in the central area. (3) Among these characteristics, the comprehensive efficiency and pure technical efficiency of the star hotels in the eastern region are the highest, while the scale efficiency is highest in the western region. (4) The degree of coupled coordination maintains stability overall despite fluctuations, with the overall direction being toward healthy development. The system coupling coordinated development is complex and diverse, and the coupled coordination span is large, with the coupled coordination degree decreasing gradually from east to west in spatial distribution.
Learning Advanced Brain Computer Interface Technology
Authors: Tao Wang , Linyan Wu , Yanping Li , Nuo Gao , Weiran Zhang
Published: April 2019

Feature extraction is an important step in electroencephalogram (EEG) processing of motor imagery, and the feature extraction of EEG directly affects the final classification results. Through the analysis of various feature extraction methods, this article finally selects Common Spatial Patterns (CSP) and wavelet packet analysis (WPA) to extract the feature and uses Support Vector Machine (SVM) to classify and compare these extracted features. For the EEG data provided by GRAZ University, the accuracy rate of feature extraction using CSP algorithm is 85.5%, and the accuracy rate of feature extraction using wavelet packet analysis is 92%. Then this paper analyzes the EEG data collected by Emotiv epoc+ system. The classification accuracy of wavelet packet extracted features can still be maintained at more than 80%, while the classification accuracy of CSP extracted feature is decreased obviously. Experimental results show that the method of wavelet packet analysis towards competition data and Emotiv epoc+ system data can both get a desirable outcome.
Motivating Language and Intent to Stay in a Backsourced Information Technology Environment
Authors: Farr Lori , Lind Mary
Published: April 2019

Information technology (IT) backsourcing is a recent phenomenon that is gaining momentum because effective sourcing strategy can have major implications for organizations regarding financial investments, IT infrastructure, and changes in employee outcomes. Recent studies suggest that organizations are bringing their previously outsourced IT operations and services back in-house with one reason being employee dissatisfaction with prior outsourcing experiences. The results of this study indicate that for every 10% increase in motivating language, one can expect to see a 4.3% increase in an IT employee's intent to stay with an organization during a time when backsourcing is occurring.
Retaining Clients in B2B E-Marketplaces
Authors: Jiang Qiqi , Phang Chee Wei , Tan Chuan-Hoo , Chi Jiayu
Published: April 2019

Business-to-business (B2B) e-marketplaces serve local small and medium-sized enterprises (SMEs) by assisting them in connecting with potential overseas buyers. They leverage multiple channels to connect with and bring potential leads to SMEs. The authors' understanding of such an intermediary has been either largely impaired by limited studies on the services that e-marketplaces should offer or implicitly deduced from business-to-consumer studies. In this work, the authors attempt to unveil whether the efforts that an e-marketplace has made are associated with the continuance of its SME clients. To answer this research question, a set of data from a B2B e-marketplace connecting qualified SMEs with overseas buyers was used for analysis, and they discovered three results. First, generating many online leads is negatively associated with SMEs' continuance with such an e-marketplace company. Second, organizing many online videoconferencing meetings between SMEs and buyers can promote this tendency, which is different from organizing many offline meetings. Third, onsite visits that e-marketplace salespersons make can attenuate the negative effect of the generation of online leads. Their follow-up interviews unveiled that SMEs only desire sufficient attention to obtain tangible results from a B2B e-marketplace.
Do We Trust the Internet?
Authors: Howah Kenneth , Chugh Ritesh
Published: April 2019

The threat profile of spyware is increasing rapidly when we consider the pervasiveness of computing in everyday life. The surreptitious nature of spyware can lead to information mining, data theft and exploitation of stolen data. This article aims to explore the relationship between trust in the Internet and neglecting risks in downloading and installing free potentially spyware-infected software. This study found that trust can be viewed as an indirect function of ignorance and overconfidence through the mechanism of the calculated probability of risk. An enhanced model of trust, based on Li and Betts' trust model has been proposed with two additional vectors. The inference drawn from the study is that in most users' minds, the calculated or perceived risk is substantially less than the anticipated benefit of the software. The analysis shows that users trust the Internet when it comes to downloading and installing potentially spyware-infected software, although such nonchalant trust appears to be based on ignorance and over-confidence.
Does E-Government Raise Effectiveness and Efficiency?
Authors: Nam Taewoo
Published: April 2019

This article examines the influence of e-government maturity on government effectiveness and efficiency with a cross-country view. To that end, it uses two-stage least square regression, considering the endogeneity of e-government. The regression-based analysis on various global indicators finds that e-government significantly contributes to enhancing government effectiveness but fails to substantially raise government efficiency. Political, economic, and cultural disparities across countries affect the variation in the impact of e-government on government effectiveness and efficiency. The level of democracy has a curvilinear relationship with government efficiency, and thus this study identifies non-democracies with well-performing governments.
The Effects of Image-Based Online Reviews on Customers' Perception Across Product Type and Gender
Authors: Liu Yuming , Du Rong
Published: April 2019

Online vendors consider image online reviews as an important format to improve customers' buying decision. Prior research examined the influence of review presentation format, but did not focus on image format. Little is known about customers' perception on image online reviews. This study developed a theoretical model to analyze the effect of image reviews across product type and gender. The 2×2×2 between-subject experimental design was conducted to test hypotheses. The results demonstrated that compared to text review, the influence of image format on customers' perception was more significant, but in varying degrees across product type and gender. This study found that image format had more positive impact for experience product's understanding compared to search product. The result also showed that the effect of image format on experience product was not significant greater for females than males, but the perception improvement degree from text to image reviews was saliently different between genders. This study discussed theoretical and managerial contributions of these results.
Understanding and Predicting Behavioral Intention to Adopt Mobile Banking
Authors: Hong Ilyoo Barry
Published: April 2019

Although mobile banking provides cost-saving opportunities as well as convenient banking experience for customers, today's banks still face challenges when deploying the technology because a good number of customers are reluctant to use mobile banking for personal reasons. This article is an empirical investigation of the determinants of the intention to use mobile banking services. The determinants are grouped into two categories including personal factors and social influence factors. The authors conducted an empirical analysis using 751 survey responses collected from present users of mobile banking services. The results of the analysis reveal that all the personal factors have positive relationships with the intention to use mobile banking services. On the other hand, it was found that of the social influence factors, perceived herding behavior has a significantly positive relationship with the intention to use mobile banking services, whereas subjective norm is not significantly related to the intention. The authors provide practical as well as academic implications of the research findings.
Interaction of Riboflavin-5-Phosphate With Liposome Bilayers
Authors: Gupta Anju , Kalyanram Poornima , Stadler Istvan
Published: April 2019

Riboflavin presents tremendous potential as a photosensitizing agent for photodynamic therapy (PDT) for treating microbial infection and cancer therapy. Encapsulation of riboflavin can improve its bioavailability and stability while making the clinical applications more efficient. The authors' detailed study on cellular inhibition of liposome encapsulated riboflavin-5-phosphate investigation, and the effect of unencapsulated riboflavin on liposome bilayers aims to improve the efficiency of cellular delivery of riboflavin. Nano-sized liposomes composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol were used in this study. Cell studies demonstrate high inhibition rates for the lipsome-encapsualted high concentration riboflavin formulations in the presence of blue light, despite the lower encapsulation lading.
Utilization of XSYTIN-1 Tool in Electrically-Assisted Friction Stir Welding of Dissimilar Metals - Al 6061-T651 to Mild Steel
Authors: Shaffer Derek , Grimm Tyler J. , Ragai Ihab , Roth John
Published: April 2019

Friction stir welding (FSW) is a solid-state metal fusion process that is characterized by several benefits over comparable processes such as a reduction in energy input and low part distortion. This process has been shown to hold great potential in the fusion of dissimilar metals, a technology highly sought after in the aerospace and automotive industries for its promising weight-reduction capabilities. Furthermore, electrically-assisted FSW (EAFSW) is the supplementation of the FSW process with an electrical current. This modification has been shown to improve many parameters; however, the current literature related to this subject is scarce. Herein, the fusion of Al 6061-T651 to mild steel is performed using EAFSW methods. A novel tool constructed a proprietary ceramic, XSYTIN-1, is also tested in this application. It was found that EAFSW improved material flow between the constituent materials; however, was unable to increase the joint strength of the weld. Additionally, it was found that the XSYTIN-1 tool did not exhibit any significant differences when compared to a conventional steel tool.
Shedding new light upon circadian emergence rhythmicity in the mountain pine beetle (Coleoptera: Curculionidae: Scolytinae)
Authors: Wertman Debra L. , Bleiker Katherine P.
Published: April 2019

The phenological behaviours of temperate insects can be highly controlled by photoperiod. Some foundational studies of the mountain pine beetle, Dendroctonus ponderosae (Hopkins) (Coleoptera: Curculionidae), documented a diurnal emergence rhythm that was asynchronous with maximum daily temperatures in the field and persisted under constant temperature and light conditions. In the 1970s, researchers hypothesised that this emergence rhythm was regulated by an endogenous circadian mechanism. Reflecting upon these historical data, we consider that a diurnal pattern of D. ponderosae emergence may result from photoperiodic entrainment of the circadian clock during the immature stages. Mechanistically, we suggest that the long-wavelength-sensitive opsin that we previously found to be expressed across D. ponderosae life stages could mediate, from beneath the bark, the input of light–dark cycle cues that are usually required for entrainment of the insect circadian clock.
GM-CSF– and IRF4-Dependent Signaling Can Regulate Myeloid Cell Numbers and the Macrophage Phenotype during Inflammation
Authors: Lee Ming-Chin , Lacey Derek C. , Fleetwood Andrew J. , Achuthan Adrian , Hamilton John A. , Cook Andrew D.
Published: April 2019

Studies have demonstrated the importance of a GM-CSF→IFN regulatory factor 4 (IRF4)→CCL17 pathway, first identified in monocytes/macrophages, for arthritic pain and disease development. In this study, we further investigated the involvement of this new pathway in shaping the inflammatory response using the zymosan-induced peritonitis (ZIP) model. ZIP (8 mg of zymosan, i.p., day 0) was induced in C57BL/6 wild-type (WT), GM-CSF−/−, Irf4−/−, and Ccl17E/E mice. In comparison with WT mice, GM-CSF−/− and Irf4−/− mice had a reduced ZIP response, as judged by a reduced number of neutrophils and macrophages in the peritoneal cavity. Moreover, the phenotype of the ZIP macrophages was altered by a lack of GM-CSF or IRF4 (increased IL-10 secretion and Arg1 mRNA expression), with IRF4 levels being lower in GM-CSF−/− ZIP macrophages than in the WT cells. In addition, GM-CSF ̶IRF4 signaling upregulated MHC class II expression in ZIP macrophages and bone marrow–derived macrophages. Although Ccl17 mRNA expression was reduced in ZIP macrophages in the absence of either GM-CSF or IRF4, thus supporting the presence of the new pathway in inflammatory macrophages, CCL17 did not modulate the inflammatory response, both in terms of number of myeloid cells or the macrophage phenotype. Thus, during an inflammatory response, both macrophage numbers and their phenotype can depend on GM-CSF– and IRF4-dependent signaling independently of CCL17.
Changing Trends in Adolescent Alcohol Use among Czech School-Aged Children from 1994 to 2014
Authors: Kážmér Ladislav , Csémy Ladislav
Published: April 2019

Background

For an efficient planning of public health policy, the regular monitoring over health-related behaviors among vulnerable population groups is necessary. The aim of this study is to examine the temporal trends in alcohol use among the Czech adolescent population.

Design and methods

Data from the Health Behaviour in Schoolaged Children (HBSC) project conducted in Czechia from 1994 to 2014 were used. Adolescent alcohol use was assessed via two indicators: i) weekly alcohol use (beer, wine, and/or spirit), ii) repeated lifetime drunkenness (having been drunk on two or more occasions in life). Trends in alcohol use were modelled separately for boys and girls. Binary logistic regression was conducted with survey period as an independent predictor of the alcohol indicator.

Results

There were significant changes in adolescent alcohol use since 1994. Between 1994 and 2010, there was a gradual upward in the prevalence. However, in the recent period of 2014, an unprecedented drop in alcohol use was recorded.

Conclusions

Despite the significant drop in the prevalence of alcohol use among the Czech youth in recent years, alcohol drinking in adolescence remains an important challenge for the national health policy. Further research will show whether these changes in adolescent health-related behavior are of a temporary or a permanent nature.
Women’s prospects for career advancement: Narratives of women in core mining positions in a South African mining organisation
Authors: Moalusi Kgope P. , Jones Candice M.
Published: April 2019

Orientation: Even though there has been a phenomenal increase in the number of women employed in the mining industry, the figures hide many gender inequalities as the gendered impediments to career advancement persist despite South Africa’s remarkable equity policy regime. However, it is unclear, from the perspective of the women themselves, how their career advancement is encumbered.Research purpose: This study reflects on the prospects for career advancement by exploring the work and organisational experiences of women in core mining positions in an open-cast mining organisation in South Africa.Motivation for the study: To reflect on the prospects for career advancement of women in core mining positions.Research approach, design and method: Eight professional women, selected through a purposive sampling procedure, participated in in-depth unstructured interviews. Data were analysed using Creswell’s simplified version of the Stevick–Colaizzi–Keen method, guided by the lens of gendered organisations.Main findings: Three themes emerged: (1) male domination that has marginalised women and compelled them to emulate masculinity has legitimised existing gender barriers, (2) the long, awkward and unpredictable hours of work have deepened women’s time constraints because they have to combine the home or family caretaker role with work, and (3) the essence of being a woman in a mining organisation.Practical/managerial implications: The study may present South African managers with a better understanding of how work and organisational features, policies, daily practices and discourses impede career advancement of women in core mining positions. Organisations should train managers to create conditions that minimise barriers and maximise performance and advancement, and align retention strategies.Contribution/value-add: This study builds on existing knowledge about career advancement of women by providing new and valuable information specific to women in core mining positions in an open-cast mining organisation in South Africa, seen through the lens of gendered organisational theory. The findings highlight the need for organisational theory research that is responsive to the subtle issues and gendered assumptions that sustain encumbrances to women’s career trajectories.
Unsmoothable group actions on compact one-manifolds
Authors: Baik Hyungryul , Kim Sang-hyun , Koberda Thomas
Published: April 2019

We show that no finite index subgroup of a sufficiently complicated mapping class group or braid group can act faithfully by

C^{1+\mathrm {bv}}

diffeomorphisms on the circle, which generalizes a result of Farb–Franks, and which parallels a result of Ghys and Burger–Monod concerning differentiable actions of higher rank lattices on the circle. This answers a question of Farb, which has its roots in the work of Nielsen. We prove this result by showing that if a right-angled Artin group acts faithfully by

C^{1+\mathrm {bv}}

diffeomorphisms on a compact one-manifold, then its defining graph has no subpath of length 3. As a corollary, we also show that no finite index subgroup of Aut

(F_n)

or Out

(F_n)

for

n \geq 3

, of the Torelli group for genus at least 3, and of each term of the Johnson filtration for genus at least 5, can act faithfully by

C^{1+\mathrm {bv}}

diffeomorphisms on a compact one-manifold.
Eta invariants and the hypoelliptic Laplacian
Authors: Bismut Jean-Michel
Published: April 2019

The purpose of this paper is to give a new proof of the results of Moscovici and Stanton on orbital integrals associated with eta invariants on compact locally symmetric spaces. Moscovici and Stanton used methods of harmonic analysis on reductive groups. Here, we combine our approach to orbital integrals that uses the hypoelliptic Laplacian with the introduction of a rotation on certain Clifford algebras. Probabilistic methods play an important role in establishing key estimates. In particular, we construct a suitable Itô calculus associated with certain hypoelliptic diffusions.
Evidence of small-scale quasi-isentropic mixing in ridges of extra-tropical baroclinic waves
Authors: Kunkel Daniel , Hoor Peter , Kaluza Thorsten , Ungermann Jörn , Kluschat Björn , Giez Andreas , Lachnitt Hans-Christoph , Kaufmann Martin , Riese Martin
Published: April 2019

Abstract. Stratosphere–troposphere exchange within extratropical cyclones provides the potential for anthropogenic and natural surface emissions to rapidly reach the stratosphere as well as for ozone from the stratosphere to penetrate deep into the troposphere, even down into the boundary layer. The efficiency of this process directly influences the surface climate, the chemistry in the stratosphere, the chemical composition of the extratropical transition layer, and surface pollution levels. Here, we present evidence for a mixing process within extratropical cyclones which has gained only little attention so far and which fosters the transport of tropospheric air masses into the stratosphere in ridges of baroclinic waves. We analyzed airborne measurement data from a research flight of the WISE (Wave driven isentropic exchange) campaign over the North Atlantic in autumn 2017 supported by forecasts from a numerical weather prediction model and trajectory calculations. Further detailed process understanding is obtained from experiments of idealized baroclinic life cycles. The major outcome of this analysis is that air masses mix in the region of the tropopause and potentially enter the stratosphere in ridges of baroclinic waves at the anti-cyclonic side of jet without changing their potential temperature drastically. This quasi-isentropic exchange occurs above the outflow of warm conveyor belts, in regions which exhibit enhanced static stability in the lower stratosphere and a Kelvin–Helmholtz instability across the tropopause. The enhanced static stability is related to radiative cooling below the tropopause and the presence of small scale waves. The Kelvin–Helmholtz instability is related to vertical shear of the horizontal wind associated to small scale waves at the upper edge of the jet-stream. The instability leads to the occurrence of turbulence and consequent mixing of trace gases in the tropopause region. While the overall relevance of this process has yet to be assessed, it has the potential to significantly modify the chemical composition of the extratropical transition layer in the lowermost stratosphere in regions which have previously gained only little attention in terms of mixing in baroclinic waves.
Characterization and evaluation of AIRS-based estimates of the deuterium content of water vapor
Authors: Worden John R. , Kulawik Susan S. , Fu Dejian , Payne Vivienne H. , Lipton Alan E. , Polonsky Igor , He Yuguang , Cady-Pereira Karen , Moncet Jean-Luc , Herman Robert L. , Irion Fredrick W. , Bowman Kevin W.
Published: April 2019

Abstract. Single-pixel tropospheric retrievals of HDO and H2O concentrations
are retrieved from Atmospheric Infrared Sounder (AIRS) radiances using the
optimal estimation algorithm developed for the Aura Tropospheric Emission
Spectrometer (TES) project. We evaluate the error characteristics and
vertical sensitivity of AIRS measurements corresponding to 5 d of TES data
(or five global surveys) during the Northern Hemisphere summers between 2006
and 2010 (∼600 co-located comparisons per day). We find that the
retrieval characteristics of the AIRS deuterium content measurements have
similar vertical resolution in the middle troposphere as TES but with
slightly less sensitivity in the lowermost troposphere, with a typical
degrees of freedom (DOFS) in the tropics of 1.5. The calculated measurement
uncertainty is ∼30 ‰ (parts per
thousand relative to the deuterium composition of ocean water) for a
tropospheric average between 750 and 350 hPa, the altitude region where AIRS
is most sensitive, compared to ∼15 ‰ for the TES data.
Comparison with the TES data also indicates that the uncertainty of a single
target AIRS HDO ∕ H2O measurement is ∼30 ‰.
Comparison of AIRS and TES data between 30∘ S and 50∘ N
indicates that the AIRS data are biased low by ∼-2.6 ‰ with a
latitudinal variation of ∼7.8 ‰. This latitudinal variation is
consistent with the accuracy of TES data compared to in situ measurements,
suggesting that both AIRS and TES have similar accuracy.
Interrelationships among soil nitrogen transformation rates, functional gene abundance and soil properties in a tropical forest with exogenous N inputs
Authors: Nie Yanxia , Han Xiaoge , Chen Jie , Wang Mengcen , Shen Weijun
Published: April 2019

Abstract. Elevated nitrogen (N) deposition affects soil N transformations in the N-rich soil of tropical forests. However, the change in soil functional microorganisms responsible for soil N cycling remains largely unknown. Here, we investigated the variation in soil inorganic N content, net N mineralization (Rm), net nitrification (Rn), inorganic N leaching (Rl), N2O efflux and N-related functional gene abundance in tropical forest soil over a two-year period with four levels of N addition. The responses of soil N transformations (in situ Rm, Rn and Rl) to N additions were delayed during the first year of N inputs. The Rm, Rn, and Rl increased with the medium nitrogen (MN) and high nitrogen (HN) treatments relative to the control treatments in the second year of N additions. Furthermore, the Rm, Rn, and Rl were higher in the wet season than in the dry season. The Rm and Rn were predominately driven by the lower C : N ratio under N addition in the dry season but by higher microbial biomass in the wet season. Throughout the study period, high N additions increased the annual N2O emissions by 78 %. Overall, N additions significantly facilitated soil N availability (Rm and Rn) and N loss (Rl and N2O emission), which had a stimulating effect on N transformations. In addition, the MN and HN treatments increased the ammonia-oxidizing archaea (AOA) abundance by 17.3 % and 7.5 %, respectively. Meanwhile, the HN addition significantly increased the abundance of nirK-denitrifiers but significantly decreased the abundance of ammonia-oxidizing bacteria (AOB) and nosZ-containing N2O reducers. To some extent, the variation in functional gene abundance was related to the corresponding N transformation processes. Partial least squares path modelling (PLS-PM) indicated that inorganic N contents had significant negative direct effects on the abundances of N-related functional genes in the wet season, implying that chronic N deposition would have a negative effect on the N-cycling-related microbes and the function of N transformation.
N2O changes from the Last Glacial Maximum to the preindustrial – Part II: Terrestrial N2O emissions constrain carbon-nitrogen interactions
Authors: Joos Fortunat , Spahni Renato , Stocker Benjamin D. , Lienert Sebastian , Müller Jurek , Fischer Hubertus , Schmitt Jochen , Prentice I. Colin , Otto-Bliesner Bette , Liu Zhengyu
Published: April 2019

Abstract. Land ecosystems currently take up a quarter of the human-caused carbon dioxide emissions. Future projections of this carbon sink are strikingly divergent, leading to major uncertainties in projected global warming. This situation partly reflects our insufficient understanding of carbon-nitrogen (C-N) interactions and particularly of the controls on biological N fixation (BNF). It is difficult to infer ecosystem responses for century time scales, relevant for global warming, from the comparatively short instrumental records and laboratory or field experiments. Here we analyse terrestrial emissions of nitrous oxide (N2O) over the past 21,000 years as reconstructed from ice-core isotopic data and presented in part I of this study. Changing N2O emissions are interpreted to reflect changes in ecosystem N loss, plant available N, and BNF. The ice-core data reveal a 40 % increase in N2O emissions over the deglaciation, suggestive of a highly dynamic global N cycle whereby sources of plant-available N adjust to meet plant N demand and loss fluxes. Remarkably, the increase occurred in two steps, each realized within maximum two centuries, at the onsets of the northern hemisphere warming events around 14,600 and 11,700 years ago. We applied the LPX-Bern dynamic global vegetation model in deglacial simulations forced with Earth System Model climate data to investigate N2O emission patterns, mechanisms, and C-N coupling. The reconstructed increase in terrestrial emissions is broadly reproduced by the model, given the assumption that BNF positively responds to increasing N demand by plants. In contrast, assuming time- and demand-independent levels of BNF in the model to mimic progressive N limitation of plant growth results in N2O emissions that are incompatible with the reconstruction. Our results suggest the existence of (a) strong biological controls on ecosystem N acquisition, and (b) flexibility in the coupling of the C and N cycles during periods of rapid environmental change.
Dynamics of wormhole formation in fractured limestones
Authors: Dreybrodt Wolfgang , Gabrovšek Franci
Published: April 2019

Abstract. Reactive transport in porous or fractured media often results in an evolution
of highly conductive flow channels, often referred to as “wormholes”. The
most spectacular wormholes are caves in fractured limestone terrains. Here, a
model of their early evolution is presented. The modeling domain is a
two-dimensional square net consisting of one-dimensional fractures
intersecting each other in a rectangular grid. Fractures have given width b
and length l, and to each fracture a constant aperture width, a
(homogeneous net), or an aperture width taken from a lognormal statistical
distribution (heterogeneous net) is assigned. The boundary conditions are
constant head h at the input driving the water downstream to the output at
h=0. Linear dissolution kinetics, controlled by surface kinetics and
diffusion, are active. First we discuss the simple case of a homogeneous net.
Two steps in its evolution are observed. In the first, all fractures are
widened evenly and a homogeneous even dissolution front progresses slowly
into the aquifer. The second step is triggered by an instability when, due to
small perturbations, some of the foremost fractures gain length compared to
the neighboring ones. Then, these fractures discharge flow using the parallel
resistances of the net. This way they attract more fresh aggressive water and
their propagation is enhanced. Several wormholes (caves) are penetrating into
the aquifer but only one reaches the output, whereas the others stop growing
due to the redistribution of hydraulic heads caused by the leading wormhole.
The mechanisms governing the evolution of a single wormhole are explored by
increasing the aperture width of one selected input fracture by Δa≪a. In this case, only one single wormhole is created and inspection of the
flow rates along it reveal the mechanism of flow enhancement in detail. If
one uses a heterogeneous net, the first step of evolution is suppressed
because of the large perturbations, and wormholes start to grow immediately.
We have also modeled the case of several competing wormholes in a homogeneous
net by inserting appropriate seeds. We find that there is a critical distance
between the wormholes. Within this distance only one wormhole survives,
whereas there is no interaction between them when they are separated by more
than the critical distance. We also answer the following question: why do
wormholes in a two-dimensional model exhibit breakthrough times at least
1 order of magnitude smaller than a one-dimensional model representing the
aquifer by one single plane-parallel fracture of the same dimensions?
Finally, we present several scenarios with non-homogeneous distribution of
initial aperture widths. In these, a uniform dissolution front does not
develop and wormholes start to grow immediately, which is more likely
expected in nature.
Carbon, nitrogen and sulfur (CNS) status and dynamics in Amazon basin upland soils, Brazil
Authors: Matschullat Jörg , Monteiro Bezerra de Lima Roberval , von Fromm Sophie F. , Pospiech Solveig , Ramos Andrea M. , Coimbra Martins Gilvan , Lenhart Katharina
Published: April 2019

Abstract. Given the dimensions of the Amazon basin (7.5 million km2), its internal dynamics, increasing anthropogenic strain on this large biome, and its global role as one of two continental biospheric tipping elements, it appears crucial to have data-based knowledge on carbon and nitrogen concentrations and pools as well as on possible intra-annual dynamics. We quantified carbon (Ct, Corg), nitrogen (N) and sulfur (S) concentrations in litter (ORG) and mineral soil material (TOP 0–20 cm, BOT 30–50 cm) of upland (terra firme) oxisols across Amazonas state and present a first pool calculation. Data are based on triplicate seasonal sampling at 29 sites (forest and post-forest) within the binational project EcoRespira-Amazon (ERA). Repeated sampling increased data accuracy and allows for interpreting intra-annual (seasonal) and climate-change related dynamics. Extreme conditions between the dry season in 2016 and the subsequent wet season (ENSO-related) show differences more clearly. Median CNS in the Amazon basin TOP soils (Ct 1.9, Corg 1.6, N 0.15, S 0.03 wt-% under forest canopy) as well as Corg / N ratios show concentrations similar to European soils (FOREGS, GEMAS). TOP Ct concentrations ranged from 1.02 to 3.29 wt-% (medianForest 2.17 wt-%; medianPost-Forest 1.75 wt-%), N from 0.088 to 0.233 wt-% (medianForest 0.17 wt-%; medianPost-Forest 0.09 wt-%) and S from 0.012 to 0.051 wt.-% (medianForest 0.03 wt.-%; medianPost-Forest 0.02 wt-%). Corg / N ratios ranged from 6 to 14 (median 10). A first pool calculation (hectare-based) illustrates forest versus post-forest changes. The elements are unevenly distributed in the basin with generally higher CNS values in the central part (Amazonas graben) as compared to the southern part of the basin. Deforestation and drought conditions lead to C and N losses – within 50 years after deforestation, C and N losses average 10 to 15 %. Regional climate change with increased drought will likely speed up carbon and nitrogen losses.