bluuebunny/crossref_metadata_2025 huggingface dataset:
Issues in Feathers Application in the Seoul Metropolitan Area
Authors: Do Lee Won , Joh Chang-Hyeon , Cho Sungjin , Kochan Bruno
Published: January 2018

Over the last decades, the trip-based approach, also known as the four-step model, has been playing an unrivaled role in transportation demand research in Korea. It has been used to predict changes in traffic volume resulting from new transportation policy measures, and also has allowed conducting benefit-cost analyses for new infrastructure provisions. It has been increasingly difficult for the trip-based model to anticipate individual responses to new transportation policy inputs and infrastructure provision as the society becomes personalized and diversified. Activity-Based Modeling (ABM) approaches, predicting travel demand derived from individual activity participations, were introduced to complement the trip-based approach in this regard. The chapter introduces the Seoul ABM project that aims to first apply FEATHERS as an ABM to the data collected in Seoul Metropolitan Area (SMA) and then develop a prototype of the ABM framework for Korea. More specifically, the chapter first briefly describes SMA in comparison with Flanders in Belgium and other countries. It then introduces related research works in Korea and the background of the Seoul ABM project. After these, a FEATHERS framework applied for the Seoul ABM project is described with its data requirements. Major issues of and solutions to the Seoul ABM project are then discussed with regard to the data preprocessing. The chapter ends with a summary and future work.
Value of Adaptation of Methodologies Between Different Knowledge Areas
Authors: Manchado-Pérez Eduardo , López-Forniés Ignacio , Berges-Muro Luis
Published: January 2018

Project-based learning (PBL) is a powerful tool for teaching that helps students to get the best in terms of ratio effort/learning outcomes, especially in studies with a very practical basis, such as university degree studies in engineering. A way of getting even more out of this is by means of the adaptation of methodologies from different knowledge areas, because this allows the launch of innovative ways of working with certain guarantees of success from the very first moment, and at the same time to integrate skills from different fields within a shared context. Furthermore, it helps to put into practice some transversal competences, which are very useful for future professionals. The chapter also includes some case studies on the successful adaptation of different methodologies coming from different fields such as graphic design, biology, and social sciences in the context of a university engineering degree in industrial design and product development.
A Systematic Review of Attributes and Techniques for Open Source Software Evolution Analysis
Authors: Saini Munish , Chahal Kuljit Kaur
Published: January 2018

Many studies have been conducted to understand the evolution process of Open Source Software (OSS). The researchers have used various techniques for understanding the OSS evolution process from different perspectives. This chapter reports a meta-data analysis of the systematic literature review on the topic in order to understand its current state and to identify opportunities for the future. This research identified 190 studies, selected against a set of questions, for discussion. It categorizes the research studies into nine categories. Based on the results obtained from the systematic review, there is evidence of a shift in the metrics and methods for OSS evolution analysis over the period of time. The results suggest that there is a lack of a uniform approach to analyzing and interpreting the results. There is need of more empirical work using a standard set of techniques and attributes to verify the phenomenon governing the OSS projects. This will help to advance the field and establish a theory of software evolution.
A WDO Framework for Optimal Deployment of DGs and DSCs in a Radial Distribution System Under Daily Load Pattern to Improve Techno-Economic Benefits
Authors: Injeti Satish Kumar , Kumar Thunuguntla Vinod
Published: January 2018

This article presents a methodology to determine optimal locations and sizes of DGs (Distributed Generator) and DSCs (D-STATCOM) simultaneously in a radial distribution network during a daily load pattern to improve the techno-economic benefits. An effective weighted objective function has been designed to address daily power loss minimization of the three techno-economic benefits, improvement of daily voltage profile and maximization of net annual savings due to the placement of DGs and DSCs. A repetitive backward-forward sweep based load flow has been used to calculate the daily power loss and bus voltages. To optimize the designed objective function, an efficient and simple nature-inspired wind driven optimization (WDO) algorithm has been used. To validate the effectiveness of the proposed methodology, different scenarios are considered and a detailed outcome analysis is presented.
From Citizens to Decision-Makers
Authors: Boukchina Eya , Mellouli Sehl , Menif Emna
Published: January 2018

Citizens' participation is a form of democracy in which citizens are part of the decision-making process with regard to the development of their society. In today's emergence of Information and Communication Technologies, citizens can participate in these processes by submitting inputs through digital media such as social media platforms or dedicated websites. From these different means, a high quantity of data, of different forms (text, image, video), can be generated. This data needs to be processed in order to extract valuable data that can be used by a city's decision-makers. This paper presents natural language processing techniques to extract valuable information from comments posted by citizens. It applies the Latent Semantic Analysis on a corpus of citizens' comments to automatically identify the subjects that were raised by citizens.
Legal Logistics
Authors: Netten Niels , van den Braak Susan W. , Bargh Mortaza S. , Choenni Sunil , Leeuw Frans L.
Published: January 2018

This paper presents a framework to provide a unified view towards the visions of smart and open justice. The framework, coined as Legal Logistics, aims at unifying and embodying different data-centric services that exploit available and relevant data for supporting and enhancing the legitimacy and efficiency of legal systems. As such, the framework specifies the scope of data-centric services in legal systems. Such a unified view of data-centric services, enables the authors to relate these services to each other and to their operational context, and better streamline data-centric based innovations in legal systems. Two data-centric services realized for the Dutch criminal justice system will be discussed. These services innovatively integrate different datasets in order to give some insights about the well-functioning and budgetary needs of the Dutch legal system. These use cases primarily illustrate the typical challenges and benefits of realizing the vision of smart justice. Secondarily, they illustrate the relevancy and usefulness of the embodying Legal Logistics framework.
Kinova Modular Robot Arms for Service Robotics Applications
Authors: Campeau-Lecours Alexandre , Lamontagne Hugo , Latour Simon , Fauteux Philippe , Maheu Véronique , Boucher François , Deguire Charles , L'Ecuyer Louis-Joseph Caron
Published: January 2018

This article presents Kinova's modular robotic systems, including the robots JACO2 and MICO2, actuators and grippers. Kinova designs and manufactures robotics platforms and components that are simple, sexy and safe under two business units: Assistive Robotics empowers people living with disabilities to push beyond their current boundaries and limitations while Service Robotics empowers people in industry to interact with their environment more efficiently and safely. Kinova is based in Boisbriand, Québec, Canada. Its technologies are exploited in over 25 countries and are used in many applications, including as service robotics, physical assistance, medical applications, mobile manipulation, rehabilitation, teleoperation and in research in different areas such as computer vision, artificial intelligence, grasping, planning and control interfaces. The article describes Kinova's hardware platforms, their different control modes (position, velocity and torque), control features and possible control interfaces. Integration to other systems and application examples are also presented.
An Efficient Random Valued Impulse Noise Suppression Technique Using Artificial Neural Network and Non-Local Mean Filter
Authors: Jena Bibekananda , Patel Punyaban , Sinha G.R.
Published: January 2018

A new technique for suppression of Random valued impulse noise from the contaminated digital image using Back Propagation Neural Network is proposed in this paper. The algorithms consist of two stages i.e. Detection of Impulse noise and Filtering of identified noisy pixels. To classify between noisy and non-noisy element present in the image a feed-forward neural network has been trained with well-known back propagation algorithm in the first stage. To make the detection method more accurate, Emphasis has been given on selection of proper input and generation of training patterns. The corrupted pixels are undergoing non-local mean filtering employed in the second stage. The effectiveness of the proposed technique is evaluated using well known standard digital images at different level of impulse noise. Experiments show that the method proposed here has excellent impulse noise suppression capability.
Spreadsheet Error Types and Their Prevalence in a Healthcare Context
Authors: Dobell Elaine , Herold Sebastian , Buckley Jim
Published: January 2018

Spreadsheets are commonly used to inform decision making across many business sectors, despite the fact that research performed in the financial sector has shown that they are quite error-prone. However, few studies have investigated spreadsheet errors and their impact in other domains, like the healthcare sector. This article derives a lifecycle-stage classification scheme of spreadsheet error types based on an aggregation of, and extension of, existing classifications. Based on these classifications, a case study is then presented, performed to investigate the prevalence of these spreadsheet error types in an Irish healthcare setting. Results reveal that more than 90% of the spreadsheets studied contained ‘bottom-line' errors and the average cell-error rate was 13%. There was also a correlation between increased perceived impact of the spreadsheets and the number of errors identified. Recommendations from this research include providing spreadsheet training and guidelines for developers and users, and systematically managing and auditing spreadsheet development and use.
Aluminum Alloys - Fundamentals
Authors:   Metals Technical Committee
Published: January 2018

This information report is intended to give general data on the properties of aluminum and information on working, joining, forming, machining, finishing, and heat treating of aluminum.
An Examination of Pre-service Agricultural Science Teachers’ Interest and Participation in International Experiences: Motivations and Barriers
Authors: Murphrey Theresa Pesl , Lane Katy , Harlin Julie , Cherry Audie L.
Published: January 2018

The importance of creating global mindedness within pre-service agricultural science teachers through international experiences cannot be overstated. However, providing opportunities for international experiences and college students selecting to participate in these opportunities are two very different actions. Mechanisms must be put in place that can impact behavior and motivate participation. The theoretical framework for this study was based on the theory of planned behavior and motivation. Understanding why students do or do not participate in international experiences allows the development of programs to meet the targeted needs of students. The purpose of this descriptive study was to investigate pre-service agricultural science teachers’ perspectives of and motivation for international experiences in order to facilitate the development of effective international experiences. The methodology employed mixed methods that included both an online survey and interviews. The total population consisted of 39 college students of whom 31 completed the online survey and of these seven were interviewed. Findings revealed a preference for travel to a developed country as a group as well as the importance of hands-on activities and advance planning. The data provides suggestions for program planning and program preferences for college students preparing to be agricultural science teachers.
Informing Extension Program Development Through Audience Segmentation: Targeting High Water Users
Authors: Huang Pei-wen , Lamm Alexa J. , Dukes Michael D.
Published: January 2018

Human reliance on water has led to water issues globally. Although extension professionals have made efforts successfully to educate the general public about water conservation to enhance water resource sustainability, difficulty has been found in reaching high water users, defined as residents irrigating excessively to their landscape irrigation needs without awareness of the environmental impacts. This study sought to identify differences in water conservation behavior engagement between the general public and high water users to facilitate the development of extension programs targeting high water users. Florida residents (N = 516) and high water users in Florida (N = 512) were surveyed for this descriptive and comparative study. Respondents were asked to indicate their current engagement in water use behavior, water conservation strategies, and the likelihood of engaging in water conservation and related societal behaviors. Compared to the general public, high water users reported a higher frequency of engagement in water use behaviors, and were less likely to engage in water conservation and related societal behaviors. Based on the findings it is recommended that extension professionals segment the high water users from the general public as a specific clientele and develop educational programs relevant to their specific needs and behavioral patterns.
Using Perceived Differences in Views of Agricultural Water Use to Inform Practice
Authors: Lamm Alexa J. , Taylor Melissa R. , Lamm Kevan W.
Published: January 2018

Water use has become increasingly contentious as the population grows and water resources become scarcer. Recent media coverage of agricultural water use has brought negative attention potentially influencing public and decision makers’ attitudes towards agriculture. Negative perceptions could result in uninformed decisions being made that impact the agricultural industry such as increased regulation and decreased permitting. Without adequate water resources the agricultural industry will be unable to enhance or even sustain current production. This study uses knowledge gap theory to identify and compare public and local decision makers’ attitudes towards and perceptions of agricultural water use to inform educational programs and communication approaches that could assist in educating and informing about agricultural water use. The findings revealed the public had a positive attitude towards agricultural water use, which significantly differs from decision makers, who were neutral. The public is also more interested in learning about water issues, while decision makers appear to be more apathetic. The findings imply there is a need for education and communication in this realm, particularly with decision makers that are working closely with water authorities in driving water policy.
Teaching STEM through Horticulture: Implementing an Edible Plant Curriculum at a STEM-centric Elementary School
Authors: Graves Leila A. , Hughes Harrison , Balgopal Meena M.
Published: January 2018

School gardens are ideal places for students to ask and answer questions about science. This paper describes a case study of two 3rd grade teachers and two STEM coordinators who were recruited to implement and evaluate a horticultural-based curriculum developed for this study. U Informed by the Teacher-Centered Systemic Reform model we conducted a case study analysis of the beliefs and practices of these four educators. Teachers made curricular decisions based on their confidence teaching about plants, the accessibility of curricular materials, perceptions of relevancy of lessons to academic science standards, and the time constraints. One STEM coordinator reported that the curriculum addressed academic science standards, was relevant to students’ lives, and provided hands-on inquiry activities connected to the school garden. The subsequent STEM coordinator, along with the teachers, believed that garden plants do not address science standards and instead support enrichment activities. We conclude that professional development on horticultural-based curriculum for both teachers and STEM coaches is warranted.
Saving Citrus: Does the Next Generation see GM Science as a Solution?
Authors: Rumble Joy N. , Ruth Taylor K. , Owens Courtney T. , Lamm Alexa J. , Taylor Melissa R. , Ellis Jason D.
Published: January 2018

Citrus is one of Florida’s most prominent commodities, providing 66% of the total United States’ value for oranges. Florida’s citrus production decreased 21% in 2014 from the previous season, partly due to the disease citrus greening. The science of genetic modification (GM) is one of the most promising solutions to the problem. However, a majority of American adults believe foods produced using GM science are unsafe for consumption. This study investigated the diffusion of GM science among Millennial students in a College of Agriculture at a land-grant university and their intent to consume citrus from a tree developed with GM science. An online survey collected data about Rogers’ diffusion of innovation model characteristics and intent to consume GM citrus from 98 respondents. Relative advantage and compatibility of GM science were rated most favorably; observability was rated the lowest. The majority of respondents were likely or extremely likely to consume fruit or juice from GM trees. Compatibility was the only significant predictor of likelihood to consume GM citrus. A better demonstration of GM science’s relative advantage, compatibility, trialability, complexity and observability through formal education is needed to improve GM science adoption by Millennials.
Why Agriculture Teachers Leave: A National Examination of Turnover Intentions and Work-Family Conflict
Authors: Sorensen Tyson J. , McKim Aaron J. , Velez Jonathan J.
Published: January 2018

Using data from a random sample of secondary school agriculture teachers in the United States, this study explored the work-family conflict and turnover intentions of agriculture teachers. Additionally, this study sought to determine the relationship between work-family conflict and turnover intentions among agriculture teachers. Work-family conflict was split into two domains, work interference with family and family interference with work. Teachers reported the higher level of work-family conflict within the work interference with family domain. However, agriculture teachers in this study identified moderately low turnover intentions. The three variables of interest (i.e., work interference with family, family interference with work, and turnover intentions) were compared by gender with no statistically significant differences identified. The final objective of this study was to determine the relationship between the two work-family conflict variables and turnover intentions. The model predicted 18% of the turnover intentions among agriculture teachers. Only one of the predictor variables, work interference with family, was identified as a statistically significant predictor of turnover intentions. The implications of work-family conflict, specifically work interference with family, are discussed and recommendations for research and practice are explored.
State Wide Self-Assessment of General Program Standards for Agricultural Education
Authors: Sands Kelsey R. , Sacquitne Adam D. , Smalley Scott W. , Retallick Michael S.
Published: January 2018

A quality program is the ultimate goal for many secondary agricultural education programs. To ensure quality agricultural education programs, standards were established to measure the extent agricultural education programs in Iowa were implementing standards. Utilizing Ajzen’s Theory of Planned Behavior, researchers incorporated the Iowa Council on Agricultural Education standards as an evaluation tool. A census study was conducted in Iowa with high school agricultural education teachers (N = 255) to better understand the extent that standards outlined by the Iowa Council on Agricultural Education were being met in agricultural education programs. In the general program standard area, improvement is needed in the areas of utilization of stakeholders, program planning, and administration communication. The FFA standard area only had one standard not being met or exceeded while Supervised Agricultural Experience (SAE) standard area had all standards indicated being met or exceeded.
Using Epistemological Positions and Orientations to Instruction to Explore School-Based, Agricultural Educators' Perpetual Identities: A Q-Short Study
Authors: Roberts Richie , Montgomery Diane
Published: January 2018

Mounting empirical evidence suggests the conflation of teachers’ instructional orientations and personal epistemological beliefs helps form the perceptual identity of educators. The current study, therefore, sought to describe in what way Oklahoma agricultural education teachers’ epistemological beliefs and orientations toward instruction combine to form the dominant perceptual identities of school-based, agricultural education (SBAE) instructors. To accomplish this, a Q methodological approach was employed. Findings revealed three key perceptual identities of SBAE instructors: Diligent Educator, Daring Educator, and Devoted Educator. Each perceptual identity stressed the importance of experiential learning. However, positions differed in how they believed experiential learning should be delivered to students. For example, Diligent Educators maintained that learning should involve a well-designed educational plan that stresses hard work. Devoted Educators, however, placed emphasis on nurturing students throughout the learning process. Meanwhile, Daring Educators contend knowledge is more fluid and self-constructed. Using Perry’s (1970) epistemological development scheme and Bowden’s (1990) conception of phenomenographic pedagogy, recommendations for praxis are offered for each perceptual identity.
Developing Self-Efficacy: Exploring Preservice Coursework, Teaching, and Professional Development Experiences
Authors: McKim Aaron J. , Velez Jonathan J.
Published: January 2018

To extend current understanding of school-based agriculture teacher development, this study explored the relationship between teacher development experiences and the self-efficacy of early career agriculture teachers. Three teacher development experiences were of interest: (a) preservice coursework, (b) student teaching, and (c) professional development. Teacher development experiences were analyzed in relation to classroom management self-efficacy, instructional strategies self-efficacy, leadership self-efficacy, science teaching self-efficacy, and math teaching self-efficacy. The relationships between development experiences and self-efficacy were analyzed through five linear regressions with teacher development experiences as independent variables and the five areas of self-efficacy as separate dependent variables. Only statistically insignificant relationships were identified for classroom management self-efficacy and instructional strategies self-efficacy. Student teaching and professional development were statistically significant, positive predictors of leadership self-efficacy. Professional development was also identified as a statistically significant, positive predictor of science teaching self-efficacy. Additionally, preservice coursework was a significant, positive predictor of math teaching selfefficacy. Findings are discussed in relation to the social cognitive theory, with emphasis on practical recommendations to enhance teacher development.
Power of Statistical Tests Used to Address Nonresponse Error in the Journal of Agricultural Education
Authors: Johnson Donals M. , Shoulders Catherine W.
Published: January 2018

As members of a profession committed to the dissemination of rigorous research pertaining to agricultural education, authors publishing in the Journal of Agricultural Education (JAE) must seek methods to evaluate and, when necessary, improve their research methods. The purpose of this study was to describe how authors of manuscripts published in JAE between 2006 and 2015 tested for nonresponse error. Results indicated that none of the studies’ tests had acceptable power to detect small effect sizes, 14.3% had acceptable power to detect medium effect sizes, and 43% of the studies’ tests did not have acceptable power to detect large effect sizes. These findings suggest that while authors frequently find no difference between respondents and others, the tests used to detect these differences are often not powerful enough to do so, leading to higher than acceptable risk for Type II error. Using the theory of planned behavior as a framework, we highlight these findings to spur change within the profession’s expectations of reporting statistical power when testing for nonresponse error and offer a primer to improve researchers’ perceived behavioral control over reporting power. We also offer specific suggestions for conducting and reporting the results of tests for nonresponse bias.
Using Audience Segmentation to Tailor Residential Irrigation Water Conservation Programs
Authors: Warner Laura A. , Chaudhary Anil Kumar , Rumble Joy N. , Lamm Alexa J. , Momol Esen
Published: January 2018

Today’s complex issues require technical expertise as well as the application of innovative social science techniques within Extension contexts. Researchers have suggested that a social science approach will play a critical role in water conservation, and people who use home landscape irrigation comprise a critical target audience for agriculture and natural resources professionals. This study was conducted to examine the possible role of an audience segmentation approach in addressing the complex issue of water resources. This research used descriptive discriminant analysis to assign national irrigation users to previously identified subgroups found in the literature (the water considerate majority, the water savvy conservationists, and the unconcerned water users) and compare characteristics to identify differences on a national scale. Results revealed the nation’s irrigation users are fairly water conscious. The findings implied unique subgroups exist among targeted Extension audiences relevant to specific behaviors, and Extension programs should focus on different programmatic objectives for targeting different subgroups. Differences were found among the three subgroups in water conservation behaviors, personal and social normative beliefs, use of landscape professionals for irrigation maintenance, and learning preferences. Recommendations were provided on how to use the results to develop impact-driven Extension programs.
Connecting Problem-solving Style to Peer Evaluations of Performance in Secondary Cooperative Learning Projects
Authors: Bush Sarah A. , Friedel Curtis R. , Hoerbert Lindsey R. , Broyles Thomas W.
Published: January 2018

With an evolving and expanding agricultural industry, it is crucial to provide future professionals with valuable experiences and skills in problem solving, communication, and teamwork. Agricultural summer programs for secondary students, which provide cooperative learning experiences with a focus on group work and problem solving, aim to help meet the current demand of employment in the various disciplines within agriculture. Many of these summer programs offer secondary students opportunities to learn more about agriculture, and gain experiences as they work in teams to consider the agricultural issues they may face upon entering the workforce. While adaption-innovation theory has been used in agribusinesses across the world to provide explanation to how people work together in teams to solve complex ill-defined problems, little is known regarding the degree the theory applies to secondary student learning in groups. This study utilized a quantitative, quasi-experimental design to further explore how high school students’ problem-solving styles impact their perceptions of group members in a cooperative learning experience while participating in the Virginia’s Summer Residential Governor’s School for Agriculture program. The findings and recommendations can assist instructors in providing cooperative learning experiences to their students and further maximize high school student’s experiences in working in teams and solving complex ill-defined problems associated with agricultural issues.
Effects of the Order of Abstraction and Type of Reflection on Content Knowledge when Teaching Experientially in a High School Classroom
Authors: DiBenedetto Catherine A. , Blythe Jessica M. , Myers Brian E.
Published: January 2018

In classrooms today, teachers continue to strive to enhance student knowledge and application by designing learning environments which create experiences for students to interact collaboratively, solve problems, think critically, and learn by doing. Research has indicated that teacher knowledge of the experiential learning cycle has become increasingly important to assess what was learned. This exploratory study sought to determine the effect of reflection-in and reflection-on-action regarding content knowledge, the effect the order of abstraction had on content knowledge, and if any interaction existed between type of reflection and order of abstraction on content knowledge scores of secondary agriscience students. Utilizing a 2 x 2 randomized experimental design, research was conducted in a secondary agriscience classroom. How order of abstraction and type of reflection were implemented were found to be significant in the development of discussion skills. Agriscience teachers should be made aware of the benefits on student learning outcomes when effective concrete experiences are designed for their students to engage, reflect, conceptualize, and experiment.
A Philosophical Review of Science and Society within Agricultural Education
Authors: McKim Aaron J. , Velez Jonathan J. , Lambert Misty D. , Balschweid Mark A.
Published: January 2018

We utilized philosophical and historical perspectives to analyze the interconnectedness between agricultural education, science, and society. Using historical evidence, the adaptive role of agricultural education was discussed and recommendations for future adaptability were described. Additionally, connections between agricultural education, science, and society were evaluated in light of the call for agricultural educators to illuminate the links between science and society. In our exploration, the feasibility of linking science and society within school-based agricultural education was considered as well as the motivation and competence of current agriculture teachers to link science and society. Three types of secondary agriculture teachers emerged: (a) science illuminators, (b) illumination attempters, and (c) vocational purists. Recommendations are made for research exploring how identified classifications of teachers meet the science and social learning needs of students. Additionally, recommendations include methods for operationalizing agriculture, science, and society connections to enhance student learning and the positive impact of school-based agricultural education.
Examining the Relationship Between the Perceived Adequacy of Tools and Equipmentand Perceived Competency to Teach Agricultural Mechanics
Authors: McCubbins OP , Wells Trent , Anderson Ryan G. , Paulsen Thomas H.
Published: January 2018

Agricultural mechanics holds an important place in agricultural education programs. Teacher efficacy in regards to teaching agricultural mechanics is also important. We used a questionnaire to survey agricultural education teachers in Iowa regarding agricultural mechanics. Spearman Rho correlations were used to determine the magnitude of the relationship between teachers’ perceived competency to teach agricultural mechanics skills and the adequacy of tools and equipment available to teach agricultural mechanics skills in school-based agricultural education (SBAE) programs. Correlations between tool adequacy and perceived competency to teach agricultural mechanics skills were identified as statistically significant (p < .05) in all 54 content areas addressed within the instrument. The results of the present study aligned with prior research regarding perceived competency and available teaching resources. The possibility exists that a lack of competency in a given skill area may result from, or may result in, a lack of adequate tools and equipment available to teach within that particular skill area. Perhaps the converse is instead true. We recommend that program stakeholders work to ensure that teachers are competent, and have access to adequate tools and equipment necessary, to teach agricultural mechanics.
Vertically resolved concentration and liquid water content of atmospheric nanoparticles at the US DOE Southern Great Plains site
Authors: Chen Haihan , Hodshire Anna L. , Ortega John , Greenberg James , McMurry Peter H. , Carlton Annmarie G. , Pierce Jeffrey R. , Hanson Dave R. , Smith James N.
Published: January 2018

Abstract. Most prior field studies of new particle formation (NPF) have been performed
at or near ground level, leaving many unanswered questions regarding the
vertical extent of NPF. To address this, we measured concentrations of 11–16 nm
diameter particles from ground level to 1000 m during the 2013
New Particle Formation Study at the Atmospheric Radiation Measurement
Southern Great Plains site in Lamont, Oklahoma. The measurements were
performed using a tethered balloon carrying two condensation particle
counters that were configured for two different particle cut-off diameters.
These observations were compared to data from three scanning mobility
particle sizers at the ground level. We observed that 11–16 nm diameter
particles were generated at the top region of the boundary layer, and were
then rapidly mixed throughout the boundary layer. We also estimate liquid
water content of nanoparticles using ground-based measurements of particle
hygroscopicity obtained with a Humidified Tandem Differential Mobility
Analyzer and vertically resolved relative humidity (RH) and temperature
measured with a Raman lidar. Our analyses of these observations lead to the
following conclusions regarding nanoparticles formed during NPF events at
this site: (1) ground-based observations may not always accurately represent
the timing, distribution, and meteorological conditions associated with the
onset of NPF; (2) nanoparticles are highly hygroscopic and typically contain
up to 50 % water by volume, and during conditions of high RH combined with
high particle hygroscopicity, particles can be up to 95 % water by volume;
(3) increased liquid water content of nanoparticles at high RH greatly
enhances the partitioning of water-soluble species like organic acids into
ambient nanoparticles.
Quantification of the enhanced effectiveness of NOx control from simultaneous reductions of VOC and NH3 for reducing air pollution in Beijing-Tianjin-Hebei region, China
Authors: Xing Jia , Ding Dian , Wang Shuxiao , Zhao Bin , Jang Carey , Wu Wenjing , Zhang Fenfen , Zhu Yun , Hao Jiming
Published: January 2018

Abstract. As one common precursor for both PM2.5 and O3 pollution, NOx gains great attention because its controls can be beneficial for reducing both PM2.5 and O3. However, the effectiveness of NOx controls for reducing PM2.5 and O3 are largely influenced by the ambient levels of NH3 and VOC, exhibiting strong nonlinearities characterized as NH3-limited/-poor and NOx-/VOC-limited conditions, respectively. Quantification of such nonlinearities is prerequisite to making suitable policy decisions but limitations of existing methods were recognized. In this study, a new method was developed by fitting multiple simulations of a chemical transport model (i.e., Community Multi-scale Air Quality Modeling System (CMAQ)) with a set of polynomial functions (denoted as pf-RSM) to quantify responses of ambient PM2.5 and O3 concentrations to changes in precursor emissions. The accuracy of the pf-RSM is carefully examined to meet the criteria of a mean normalized error within 2 % and a maximal normalized error within 10 % by using forty training samples with marginal processing. An advantage of the pf-RSM method is that the nonlinearity in PM2.5 and O3 responses to precursor emission changes can be characterized by quantitative indicators, including (1) peak ratio (denoted as PR) representing VOC-limited or NOx-limited condition, (2) suggested reduction ratio of VOC to NOx (denoted as VNr) to avoid increasing O3 under VOC-limited condition, (3) flex ratio (denoted as FR) representing NH3-poor or NH3-rich condition, and (4) enhanced benefits in PM2.5 reductions from simultaneous reduction of NH3 with the same reduction rate of NOx. A case study in Beijing-Tianjin-Hebei region suggested that most urban areas present strong VOC-limited condition with PR from 0.4 to 0.8 in July, implying that the NOx emission reduction rate need be greater than 20 %–60 % to pass the transition from VOC-limited to NOx-limited. A simultaneous VOC control (VNr is about 0.5–1.2) can avoid increasing O3 during the transition. For PM2.5, most urban areas present strong NH3-rich condition with PR from 0.75–0.95, implying the NH3 is sufficiently abundant to neutralize extra nitric acid produced by an additional 5 %–35 % of NOx emissions. Enhanced benefits in PM2.5 reductions from simultaneous reduction of NH3 were estimated to be 0.04–0.15 µg m−3 PM2.5 per 1 % reduction of NH3 along with NOx, with greater benefits in July when the NH3-rich condition is not as strong as in January. Thus, simultaneously reducing NH3 and VOC emission along with NOx reduction is recommended to assure the control effectiveness of PM2.5 and O3.
Sensitivity of woody carbon stocks to bark investment strategy in Neotropical savannas and forests
Authors: Trugman Anna T. , Medvigy David , Hoffmann William A. , Pellegrini Adam F. A.
Published: January 2018

Abstract. Fire frequencies are changing in Neotropical savannas and
forests as a result of forest fragmentation and increasing drought. Such
changes in fire regime and climate are hypothesized to destabilize tropical
carbon storage, but there has been little consideration of the widespread
variability in tree fire tolerance strategies. To test how aboveground
carbon stocks change with fire frequency and composition of plants with
different fire tolerance strategies, we update the Ecosystem Demography
model 2 (ED2) with (i) a fire survivorship module based on tree bark
thickness (a key fire-tolerance trait across woody plants in savannas and
forests), and (ii) plant functional types representative of trees in the
region. With these updates, the model is better able to predict how fire
frequency affects population demography and aboveground woody carbon.
Simulations illustrate that the high survival rate of thick-barked, large
trees reduces carbon losses with increasing fire frequency, with high
investment in bark being particularly important in reducing losses in the
wettest sites. Additionally, in landscapes that frequently burn, bark
investment can broaden the range of climate and fire conditions under which
savannas occur by reducing the range of conditions leading to either
complete tree loss or complete grass loss. These results highlight that
tropical vegetation dynamics depend not only on rainfall and changing fire
frequencies but also on tree fire survival strategy. Further, our results
indicate that fire survival strategy is fundamentally important in
regulating tree size demography in ecosystems exposed to fire, which
increases the preservation of aboveground carbon stocks and the coexistence
of different plant functional groups.
Plants in movement – Floristic and climatic characterization of the
New Jersey hinterland during the Palaeogene–Neogene transition in
relation to major glaciation events
Authors: Prader Sabine , Kotthoff Ulrich , McCarthy Francine M.G. , Schmiedl Gerhard , Donders Timme H. , Greenwood David R.
Published: January 2018

Abstract. Mid-Oligocene to Early Miocene terrestrial palynomorphs from the New Jersey hinterland (eastern North America: IODP-Expedition 313) were analysed, using light microscopy and scanning electron microscopy, to infer altitudinal spatial and long-term temporal vegetation migration in context of global climate change. The mesophytic forest was the most widespread vegetation type in the hinterland, with Quercus (Group Quercus, Quercus/Lobatae and aff. Group Protobalanus) being the dominant taxon. Pollen grains of the extinct genus Eotrigonobalanus (Fagaceae) are documented. To infer possible topographic palaeovegetation movements during the selected time interval terrestrial palynomorphs were assigned to six vegetation units. Relative abundances of vegetation units show weak temporal and spatial fluctuations, with the sum of bisaccate pollen grains being most pronounced. Periodic changes in vegetation units suggest movements of the plant cover responding to orbital-scale glacial-interglacial changes of the Oligocene and early Miocene. Relative abundances of several taxa (e.g. Carya) did not change significantly during the Oligocene, but alterations are recognizable when compared with an already published late Middle Miocene record from the same area, probably indicating biotic responds to environment change. A pollen-based bioclimatic analysis with four standard parameters (mean annual temperature, mean temperatures of the coldest and warmest month, mean annual precipitation) was performed to reconstruct palaeoclimatic changes indicating weak fluctuations in temperature and precipitation.
Geophysical and geochemical controls on the megafaunal community of a high Arctic cold seep
Authors: Sen Arunima , Åström Emmelie K. L. , Hong Wei-Li , Portnov Alexey , Waage Malin , Serov Pavel , Carroll Michael L. , Carroll JoLynn
Published: January 2018

Abstract. Cold seep communities around gas hydrate mounds (pingos) in the Western Barents Sea (76°N, 16°E, ~400 m depth) were investigated with high resolution, geographically referenced images acquired with an ROV and towed camera. Four pingos associated with seabed methane release hosted diverse biological communities of mainly non-seep (background) species including commercially important fish and crustaceans, as well as a species new to this area (the snow crab Chionoecetes opilio). We attribute the presence of most benthic community members to habitat heterogeneity and the occurrence of hard substrates (methane derived authigenic carbonates), particularly the most abundant phyla (Cnidaria and Porifera), though food availability and exposure to a diverse microbial community is also important for certain taxa. Only one chemosynthesis based species was confirmed, the siboglinid frenulate polychaete, Oligobrachia haakonmosbiensis. Overall, the pingo communities formed two distinct clusters, distinguished by the presence or absence of frenulates. Methane gas advection through sediments was absent below the single pingo that lacked frenulates, while seismic profiles indicated gas saturated sediment below the other frenulate colonized pingos. The absence of frenulates could not be explained by sediment sulfide concentrations, despite these worms likely containing sulfide oxidizing symbionts. We propose that high levels of seafloor methane seepage linked to sub-surface gas reservoirs support an abundant and active sediment methanotrophic community that maintains high sulfide fluxes and serves as a carbon source for frenulate worms. The pingo currently lacking a sub-surface gas source and lower methane concentrations has lower sulfide flux rates and limited amounts of carbon insufficient to support frenulates. Two previously undocumented behaviors were visible through the images: grazing activity of snow crabs on bacterial mats, and seafloor crawling of Nothria conchylega onuphid polychaetes.
Impacts of climate change and climate extremes on major crops
productivity in China at a global warming of 1.5 °C & 2.0 °C
Authors: Chen Yi , Zhang Zhao , Tao Fulu
Published: January 2018

Abstract. A new temperature goal of holding the increase in global average temperature well below 2℃ above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 ℃ above pre-industrial levels has been established in Paris Agreement, which calls for understanding of climate risk under 1.5 ℃ & 2.0 ℃ warming scenarios. Here, we evaluated the effects of climate change on growth and productivity of three major crops (i.e., maize, wheat, rice) in China during 2106–2115 at warming scenarios of 1.5 ℃ & 2.0 ℃ using the method of ensemble simulation with well-validated MCWLA family crop models, their 10 sets of optimal crop model parameters, and 70 climate projections from four global climate models. We presented the spatial patterns of changes in crop growth duration, crop yield, impacts of heat and drought stress, as well as crop yield variability and probability of crop yield decrease. Results showed that the decrease of crop growth duration and the increase of extreme events impacts in the future would have major negative impacts on crop production, particularly for wheat in north China, rice in south China and maize across the cultivation areas. By contrast, with the moderate increases in temperature, solar radiation, precipitation, and atmospheric CO2 concentration, agricultural climate resources such as light and thermal resource could be ameliorated which enhance canopy photosynthesis, and consequently biomass accumulations and yields. The moderate climate change would slightly deteriorate maize growth environment but result in much more appropriate growth environment for wheat and rice. As a result, the wheat and rice yields could increase by 3.9 % and 4.1 %, respectively, and maize yield could increase by 0.2 %, at a warming scenario of 1.5 ℃. At the warming scenario of 2.0 ℃, wheat and rice yield would increase by 8.6 % and 9.4 %, respectively, but maize yield could decrease by 1.7 %. In general, the warming scenarios would bring more opportunities than risks for the crop development and food security in China. Moreover, although variability of crop yield would increase with the change of climate scenario from 1.5 ℃ warming to 2.0 ℃ warming, the probability of crop yield decrease would decrease. Our findings highlight that the 2.0 ℃ warming scenario would be more suitable for crop production in China, but the expected increase in extreme events impacts should be paid more attention to.