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Teaching is an important part of an Extension agent's duties; however, little is empirically understood about effective teaching practices in an Extension context. The purpose of this study was to explore the adult teaching practices of exemplary extension agents. Through a nomination process, seven agents in Florida were interviewed. The analysis revealed four themes: (a) approach to teaching adults, (b) awareness of learners, (c) planning, and (d) learning to teach. Each theme had several sub-themes. Recommendations for practice and additional research are provided.

Extension agents frequently teach adult audiences, who require a different approach than youth audiences. Andragogy has been frequently used to frame research in Extension. However, it is not clear if Extension professionals apply andragogical principles in practice when teaching programs. We used Knowles' theory of andragogy and the Personal Adult Learning Style Inventory to investigate the andragogical tendencies of Extension agents who were nominated as exceptional teachers in Florida. Our study results suggest that the agents viewed as exceptional teachers in Florida embrace an andragogical philosophy when it does not conflict with their understanding of their job responsibilities.

While all learning and knowledge can be attributed to experiences, not all experiences are educative. Experiential learning is a highly utilized theory and pedagogical practice in agricultural education and has been since its inception as a discipline. The purpose of this research is to examine the theory of experiential learning as it applies to agricultural education. Therefore, this philosophical discussion aims to continue the work conducted by Roberts (2006), and aid in further understanding the phenomenon of experiential learning. Specifically, this study includes a synthesis of recent empirical research on experiential learning, especially in agricultural education settings. We also offer considerations from seminal literature by experiential learning theorists. A revised process model that emphasizes experiential learning is not a stepwise process is presented. Also, we provide revisions to the model for contextualizing experiential learning. Lastly, we present a holistic model of experiential learning that includes both the process and context of experiential learning.

An emerging challenge of closing the gap of supply and demand in School-Based Agriculture Education (SBAE) is recruiting and retaining male agricultural teachers. This case study was conducted under the lens of the Theory of Planned Behavior to examine this phenomena. Ten male participants, who were active in SBAE as youth and are currently attending a post-secondary institution, were chosen to discuss their participation in SBAE and their college major selection. The results of these interviews identified factors participants used to select a major in agricultural education versus other agricultural majors. Participants' high school agriculture teacher was found to be the most influential in students' decision to major in agriculture. Participants' parents were found to be supportive of their child's choice of major, but this was not a major factor in influencing their child's selection of major. Furthermore, enrollment in SBAE gave participants the confidence and knowledge to select majors in colleges of agriculture.

Given the shortage of agriculture teachers across the country, understanding individuals' motivation to pursue a career in teaching agricultural education is critical to developing strategies for teacher recruitment and teacher education. Several studies have investigated factors that motivate preservice and in-service agriculture teachers to pursue a career teaching agricultural education based on the Factors Influencing Teaching Choice (FIT-Choice) model. However, little research investigated the topic using different theoretical lenses or a mixed-methods approach, which could provide new perspectives on individuals' motivation to teach. To address the knowledge gap, we investigated Florida preservice teacher recruitment program participants' motivation to teach agricultural education using a mixed-methods approach from the self-determination theory and the theory of planned behavior theoretical lens. We found that individuals' intention to become agriculture teachers was statistically significantly explained by two predictors: attitude toward behavior and perceived behavioral control regarding a career in teaching agriculture. When choosing a career in teaching agriculture, the score for more self-determined motivation was substantially higher than that for less self-determined motivation. Furthermore, inspiring agriculture teachers, positive experiences with SBAE programs, a passion for teaching and agriculture, and paying it forward to students were the main factors that motivated them to pursue a career in teaching agricultural education. Based on the theoretical frameworks and the results, a model for understanding factors influencing individuals to pursue a career in teaching agriculture was proposed to broaden our understanding of the multidimensional nature of individuals' motivation to teach agriculture.

Experiential learning is widely used at the post-secondary level, but it requires intentional curricular planning, and proper facilitation from the instructor. The effects of experiential learning in agricultural education settings at the higher education level have not been tested extensively. Therefore, additional examination is needed to inform the practice of college faculty, especially those who wish to implement effective experiential learning in their teaching. The purpose of this study was to examine the effects of reflection mode (peer verbal or written journal reflection) and transfer level (same, near, or far transfer) on students' post-course knowledge retention in an undergraduate, animal science, laboratory course. In total, 114 students were divided among six treatment groups using a quasi-experimental, two-way, analysis of covariance (ANCOVA) design. There was no statistically significant interaction effect between reflection mode and transfer level on students' post course retention, nor were there statistically significant differences for theses main effects. While no treatment group was statistically significant, this does not mean that the mode of reflection or level of transfer were not effective practices. Rather, no reflection mode, transfer level, or combination thereof was more effective than the others. Practitioners of experiential education should seek to implement holistic models of experiential learning, which includes the facilitation of learner reflection and application, in order to foster an educative experience.

Abstract Potassium (K) is an essential macronutrient involved in many physiological and biochemical functions that affect a plant's susceptibility to disease. These processes include stomatal regulation, enzyme activation, and solute transport, each of which is often discussed through the lens of either plant nutrition or plant disease control. However, the interaction between these stresses and the resulting physiological and agronomic impact is an important consideration when managing a cropping system as a whole and is scarcely addressed in the literature. Therefore, a review of the literature was focused on the interaction of K nutrition and the resulting impact on plant disease control. Nutrient management, especially K, can manipulate these essential plant processes to provide the host plant with either an advantage or disadvantage in disease susceptibility, depending on the pathogen and the situation. Numerous studies have been conducted investigating the individual pathogen and host relationships, concluding that the majority of bacterial and fungal diseases decreased with increasing K nutrition, while viral diseases and nematode infections had inconsistent responses to K nutrition. These differences in the response of disease to K nutrition complicate generalizations across species and environments. Similarly, the impact of K on plant growth is affected by the concentration of each nutrient and its ratio with other nutrients. Therefore, a review of the major physiological processes that depend on plant K nutrition is discussed below with the resulting impact on plant disease control.

Today’s agriculture, food, and natural resources (AFNR) sectors face many wicked problems like climate change. Addressing these complex problems will require people to have both social and technical knowledge. However, having knowledge is insufficient. Individuals must be able to think about things as they occur in complex systems. Systems thinking has been proposed as a way of tackling complex problems. The purpose of this study was to determine if there is a continuum of systems thinking paradigms, beyond the hard systems thinking and soft systems thinking dichotomy proposed by Checkland. A novel research method called Q methodology was used, which included two steps: (a) the collection of data that forms the Q-sorts and (b) the by-person factor analysis of the Q-sorts. Overall, the findings from this study support the idea that systems thinking occurs on a continuum which includes (a) Hard systems thinking, (b) HARDsoft systems thinking, (c) SOFThard systems thinking and (d) Soft systems thinking. HARDsoft and SOFThard systems thinking were newly discovered in this research. The four systems thinking paradigms identified in this study better reflect the nuances and complexities that are associated with human thought and can provide a more specialized approach to solving complex issues.

Universities are increasingly working to better prepare students for success in the workforce and increasingly advocating high-impact learning experiences. This case study explores the short-term impacts on students who participated in a short-term service-learning study abroad program in Ireland through a lens of Transformative Learning Theory. Data collection consisted of (a) a preparticipation interview, (b) a follow-up interview, and (c) participant observation. We found evidence of all four tenets of Mezirow’s Transformative Learning Theory: (a) refining meaning schema, (b) learning new schema, (c) transforming schemes, and (d) transforming perspectives. Emergent subthemes related to service-learning or personal growth were discovered within each of these tenets. We concluded that while this program was not intentionally designed with Transformative Learning Theory as a means to deliver an educational curriculum, there are transformational learning aspects inherent to study abroad as well as service-learning. Based on this study, we offer recommendations for best practices for facilitating service-learning study abroad programs and for future research.

As we race towards 2030, the target date for achieving the U.N. Sustainable Development Goals, it is critical that we examine our approaches to agricultural development research and practice. We should not expect extraordinary results by using the approaches we have always used. Rather, we must innovate. To that end, Advancements in Agricultural Development held a Symposium on Methods of Agricultural Development Research and Practice in October 2023 on the University of Reading campus, co-hosted by the School of Agriculture, Policy and Development. We invited recognized experts from around the world to develop papers focused on innovative methods of agricultural development practice or innovative methods of agricultural development research. We had ten papers presented that were authored by 26 researchers representing 13 universities/research institutes in 6 countries. Sixteen authors attended the symposium to present their papers. A healthy dialogue followed each presentation to help authors refine their papers, resulting in the articles published in this special issue. A summary of each article is provided.

This is the annual state of the journal report for Advancements in Agricultural Development. This report: (a) highlights key accomplishments from 2023, (b) discusses changes beginning in 2024, (c) shares journal statistics from 2023, (d) presents goals for 2024, and (e) lists reviewers for the year. 2023 (Volume 4) was a banner year for Advancements in Agricultural Development (AAD), with several milestones reached. First, we published our 100th article in August. Second, AAD was accepted for inclusion in AGRICOLA, the National Library of the U.S. Department of Agriculture (https://www.nal.usda.gov/agricola). Third, AAD was also selected for inclusion in the Cabells directory (https://cabells.com/), which will allow for generating journal analytics for citations and mentions. We also introduced a new style sheet for published articles, adding the submitted, accepted, and published dates for transparency.

HBr emissions from volcanoes lead rapidly to the formation of BrO within volcanic plumes and have an impact on tropospheric chemistry, at least at the local and regional scales. The motivation of this paper is to prepare a framework for further 3D modelling of volcanic halogen emissions in order to determine their fate within the volcanic plume and then in the atmosphere at the regional and global scales. The main aim is to evaluate the ability of the model to produce a realistic partitioning of bromine species within a grid box size typical of MOCAGE (Model Of atmospheric Chemistry At larGE scale) 3D (0.5∘ × 0.5∘). This work is based on a 1D single-column configuration of the global chemistry-transport model MOCAGE that has low enough computational cost to allow us to perform a large set of sensitivity simulations. This paper uses the emissions from the Mount Etna eruption on 10 May 2008. Several reactions are added to MOCAGE to represent the volcanic plume halogen chemistry. A simple plume parameterisation is also implemented and tested. The use of this parameterisation tends to only slightly limit the efficiency of BrO net production. Both simulations with and without the parameterisation give results for the partitioning of the bromine species, of ozone depletion and of the BrO/SO2 ratio that are consistent with previous studies. A series of test experiments were performed to evaluate the sensitivity of the results to the composition of the emissions (primary sulfate aerosols, Br radical and NO) and to the effective radius assumed for the volcanic sulfate aerosols. Simulations show that the plume chemistry is sensitive to all these parameters. We also find that the maximum altitude of the eruption changes the BrO production, which is linked to the vertical variability of the concentrations of oxidants in the background air. These sensitivity tests display changes in the bromine chemistry cycles that are generally at least as important as the plume parameterisation. Overall, the version of the MOCAGE chemistry developed for this study is suitable to produce the expected halogen chemistry in volcanic plumes during daytime and night-time.

Radio frequency interference (RFI) in global navigation satellite system (GNSS) frequencies can endanger human life and safety by preventing the use of these signals for navigation and positioning, in addition to degrading measurements for science applications. Here, we use data from the Cyclone GNSS (CYGNSS) constellation to map GNSS RFI from 2017 to 2022, identify the location of several potential sources of RFI, and quantify the duration of transmission. Although our method of RFI detection can only provide a rough approximation of transmitter positions, it is possible that advanced data processing techniques could better pinpoint their locations, once guided by these observations. We find that, since the launch of CYGNSS, GNSS jammers have proliferated across the world and are often associated with the beginnings of geopolitical unrest. Our results agree well with previous studies that have also used satellite observations to map ground-based RFI transmission.

The increasing prevalence of stimulant use disorder (StUD) involving methamphetamine and cocaine has been a growing healthcare concern in the United States. Cocaine usage is associated with atherosclerosis, systolic and diastolic dysfunction, and arrhythmias. Furthermore, approximately one of every four MIs is cocaine-induced among patients aged 18 to 45. Methamphetamine use has been associated with nerve terminal damage in the dopaminergic system resulting in impaired motor function, cognitive decline, and co-morbid psychiatric disorders. Current treatment options for StUD are extremely limited, and there are currently no FDA-approved pharmacotherapies. Behavioral interventions are considered first-line treatment; however, in a recent meta-analysis comparing behavioral treatment options for cocaine, contingency management programs provided the only significant reduction in use. Current evidence points to the potential of various neuromodulation techniques as the next best modality in treating StUD. The most promising evidence thus far has been transcranial magnetic stimulation which several studies have shown to reduce risk factors associated with relapse. Another more invasive neuromodulation technique being studied is deep-brain stimulation, which has shown promising results in its ability to modulate reward circuits to treat addiction. Results showing the impact of transcranial magnetic stimulation (TMS) in the treatment of StUD are limited by the lack of studies conducted and the limited understanding of the neurological involvement driving addiction-based diseases such as StUD. Future studies should seek to provide data on consumption-reducing effects rather than craving evaluations.

Summary: Anaerobic microbial degradation of hydrocarbons is often initiated through addition of the hydrocarbon to fumarate by enzymes known as X-succinate synthases (XSSs). XSSs use a glycyl radical cofactor, which is installed by an activating enzyme (XSS-AE), to catalyze this carbon-carbon coupling reaction. The activation step, although crucial for catalysis, has not previously been possible in vitro because of insolubility of XSS-AEs. Here, we take a genome mining approach to find an XSS-AE, a 4-isopropylbenzylsuccinate synthase (IBSS)-AE (IbsAE) that can be solubly expressed in Escherichia coli. This soluble XSS-AE can activate both IBSS and the well-studied benzylsuccinate synthase (BSS) in vitro, allowing us to explore XSSs biochemically. To start, we examine the role of BSS subunits and find that the beta subunit accelerates the rate of hydrocarbon addition. Looking forward, the methodology and insight gathered here can be used more broadly to understand and engineer XSSs as synthetically useful biocatalysts.

Building human capacity through education and training programs is a key component of agricultural development. This article lays out a framework for educators working in agricultural development to use local knowledges to enhance capacity building efforts. Local knowledge systems are complex social phenomena consisting of unique combinations of ontologies/epistemologies, worldviews, and cultures of the people in a particular social/ecological context. To embrace local knowledge systems, educators should: (a) understand power, positionality, and privilege; (b) understand your learners and yourselves; (c) use participatory approaches; and (d) embrace new knowledges. The framework presented provides guidance for agricultural development practitioners; agricultural development organizations; educational institutions and others who train agricultural development practitioners; and researchers and evaluators.

This is the annual state of the journal report for Advancements in Agricultural Development. This report highlights activities and accomplishments in 2022 (Volume 3).

Abstract Background Understanding the specificity and flexibility of the algal symbiosis-host association is fundamental for predicting how species occupy a diverse range of habitats. Here we assessed the algal symbiosis diversity of three species of larger benthic foraminifera from the genus Amphistegina and investigated the role of habitat and species identity in shaping the associated algal community. Results We used next-generation sequencing to identify the associated algal community, and DNA barcoding to identify the diatom endosymbionts associated with species of A. lobifera, A. lessonii, and A. radiata, collected from shallow habitats (

University engagement within communities is becoming more important, and public land-grant universities (LGUs) are uniquely situated to create knowledge that benefits society. Intercollegiate Extension programs could be a novel approach to improving university engagement by using the Extension mission as a catalyst for socially relevant programs. However, a gap remains in the literature regarding specific guidelines to overcome barriers toward intercollegiate Extension programs. The purpose of this study was to explore how transactional factors influenced the implementation of intercollegiate Extension programs at LGUs. A qualitative descriptive phenomenological research design was used. The Organizational Change model guided the interview protocol creation. All eight participants were employed by LGUs. Template analysis was applied to the data combined with the constant comparative method. Four themes and six sub-themes emerged from the interviews. The transactional themes were: (a) promotion and tenure, (b) utilizing LGUs’ organizational structures to support intercollegiate Extension programs, (c) task and individual skills required for successful intercollegiate programs, and (d) professional recognition. Utilizing LGUs’ organizational structures to support intercollegiate Extension programs was most relevant to the success of intercollegiate programs. Intercollegiate Extension programs should use existing assets like the county-based infrastructure to assist in disseminating university knowledge relevant for addressing public needs.

Abstract Background The AGuIX® (NH TherAguix) nanoparticle has been developed to enhance radiotherapy treatment and provide strong MR contrast. These two properties have previously been investigated separately and progressed to clinical trial following a clinical workflow of separate MR imaging followed some time later by radiotherapy treatment. The recent development of MRI-linacs (combined Magnetic Resonance Imaging–linear accelerator systems enabling MRI-guided radiotherapy) opens up a new workflow where MR confirmation of nanoparticle uptake can be carried out at the time of treatment. A preclinical study was carried out to assess the suitability of a gadolinium-containing nanoparticle AGuIX® (NH TherAguix) for nano-enhanced image-guided radiotherapy on an MRI-linac. Methods Treatments were carried out on F344 Fischer rats bearing a 9L glioma brain tumour. Animals received either: (A) no treatment; (B) injection of nanoparticles followed by MRI; (C) radiotherapy with MRI; or (D) injection of nanoparticles followed by radiotherapy with MRI. Pre-clinical irradiations were carried out on the 1.0 T, 6 MV in-line Australian MRI-linac. Imaging used a custom head coil specially designed to minimise interference from the radiotherapy beam. Anaesthetised rats were not restrained during treatment but were monitored with a cine-MRI sequence. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis was used to quantify residual gadolinium in the brain in normal and tumour tissue. Results A preclinical evaluation of nano-enhanced radiation treatment has been carried out on a 1.0 T MRI-linac, establishing a workflow on these novel systems. Extension of life when combining radiotherapy with nanoparticles was not statistically different from that for rats receiving radiotherapy only. However, there was no detrimental effect for animals receiving nanoparticles and radiation treatment in the magnetic field compared with control branches. Cine-MR imaging was sufficient to carry out monitoring of anaesthetised animals during treatment. AGuIX nanoparticles demonstrated good positive contrast on the MRI-linac system allowing confirmation of tumour extent and nanoparticle uptake at the time of treatment. Conclusions Novel nano-enhanced radiotherapy with gadolinium-containing nanoparticles is ideally suited for implementation on an MRI-linac, allowing a workflow with time-of-treatment imaging. Live irradiations using this treatment workflow, carried out for the first time at the Australian MRI-linac, confirm the safety and feasibility of performing MRI-guided radiotherapy with AGuIX® nanoparticles. Follow-up studies are needed to demonstrate on an MRI-linac the radiation enhancement effects previously shown with conventional radiotherapy.

Abstract Understanding the role of dispersal and adaptation in the evolutionary history of marine species is essential for predicting their response to changing conditions. We analyzed patterns of genetic differentiation in the key tropical calcifying species of large benthic foraminifera Amphistegina lobifera to reveal the evolutionary processes responsible for its biogeographic distribution. We collected specimens from 16 sites encompassing the entire range of the species and analyzed hypervariable fragments of the 18S SSU rDNA marker. We identified six hierarchically organized genotypes with mutually exclusive distribution organized along a longitudinal gradient. The distribution is consistent with diversification occurring in the Indo‐West Pacific (IWP) followed by dispersal toward the periphery. This pattern can be explained by: (a) high dispersal capacity of the species, (b) habitat heterogeneity driving more recent differentiation in the IWP, and (c) ecological‐scale processes such as niche incumbency reinforcing patterns of genotype mutual exclusion. The dispersal potential of this species drives the ongoing range expansion into the Mediterranean Sea, indicating that A. lobifera is able to expand its distribution by tracking increases in temperature. The genetic structure reveals recent diversification and high rate of extinction in the evolutionary history of the clade suggesting a high turnover rate of the diversity at the cryptic level. This diversification dynamic combined with high dispersal potential, allowed the species to maintain a widespread distribution over periods of geological and climatic upheaval. These characteristics are likely to allow the species to modify its geographic range in response to ongoing global warming without requiring genetic differentiation.

The purpose of this study was to determine the attitudes and beliefs of school-based agriculture education (SBAE) students toward international agricultural concepts. This study builds on several previous studies (Conner, Greer, & Stripling, 2017; Elliot & Yanik, 2002; Heinert, Lavery, & Roberts, 2014; Radhakrishna, Leite, & Domer, 2003). To explore new geographic regions of the United States, two states, one from the Midwest and one from the Northwest, were purposively identified. A 46-item instrument that measures attitudes, beliefs, understanding, and instruction in relation to international agriculture developed by Radhakrishna et al. (2003) was administered to students in three schools representing both rural and urban areas. A total of 133 surveys were returned, for a 55.2% response rate. Overall, students held positive attitudes and beliefs toward international agricultural concepts. Students expressed a need to understand basic geography in relation to international agricultural concepts, and students strongly agreed to concepts and information necessary to understand international agricultural concepts. When historical data were synthesized with data from this study, mean scores from all five studies across all four constructs were consistently high. Future research should focus on how students develop their attitudes and beliefs about international agriculture.

This is the annual state of the journal report for Advancements in Agricultural Development. This report highlights activities and accomplishments from 2020 (Volume 1) and 2021 (Volume 2).

The COVID-19 pandemic of 2020 disrupted education all over the world. Teachers and students were forced to adapt to online learning. In the U.S., school-based agricultural education (SBAE) teachers faced challenges in delivering what is traditionally a hands-on curriculum. This study used a Pedagogical Design Capacity framework to understand the experiences of four SBAE teachers at different career stages and different geographic regions of the U.S. Our results showed dissatisfaction over initial changes, frustrations over changes to program outcomes, and impacts to teacher well-being. Recommendations for research, practice, and policy are provided.

In 2018, Hurricane Michael caused extensive damage in the Florida panhandle as a Category 4 hurricane. Cooperative Extension has a disaster preparedness and information dissemination role in hurricane response (Medford-Davis & Kapur, 2014; Washburn, 2006). Personal resilience focuses on reducing stress and increasing coping abilities in stressful situations. A basic qualitative research design explored UF/IFAS Extension agents’ hurricane experiences. Results suggested participants experienced some inability to balance personal and professional demands and were mentally and emotionally stressed. Participants felt fatigued and results suggested they experienced high levels of mental and emotional stress. There is scope to improve Extension agents’ personal resilience by: (1) strengthening individual levels of hardy attitudes and hardy strategies; and (2) reducing barriers such as mental and physical stress and performance deficits.

Human capacity building in Haiti’s agricultural sector can be utilized to reduce the country’s food insecurity. Haitian agricultural university and technical schools are responsible for supplying workforce ready graduates and therefore play a role in poverty reduction. Previous research has been conducted to assess these institutions from the perspective of faculty, students, and farmers. However, the employer perspective has not been considered, which could lead to a disconnect between what employers and the university believe are essential skills for graduates to obtain. This study focused on identifying the perceptions of the Haitian agricultural workforce regarding the ability of technical schools to produce graduates. This study used a basic qualitative design involving interviews of Haitian agricultural employers. The interviews revealed employers perceptive of curriculum strengths and weaknesses as well as desired employer skills for graduates. Employers also provided insight into the current job opportunities for graduates as well as what makes an “ideal” employee. We found a disconnect between jobs available and the skills being taught to graduates to fill these jobs. While employers desire employees with strong soft skills, there is a need for more technical skills to be taught at the agricultural schools.

Welcome to the first issue of Advancements in Agricultural Development. Read the introduction from the editors.

Volcanic eruptions impact climate through the injection of sulfur dioxide (SO2), which is oxidized to form sulfuric acid aerosol particles that can enhance the stratospheric aerosol optical depth (SAOD). Besides large-magnitude eruptions, moderate-magnitude eruptions such as Kasatochi in 2008 and Sarychev Peak in 2009 can have a significant impact on stratospheric aerosol and hence climate. However, uncertainties remain in quantifying the atmospheric and climatic impacts of the 2009 Sarychev Peak eruption due to limitations in previous model representations of volcanic aerosol microphysics and particle size, whilst biases have been identified in satellite estimates of post-eruption SAOD. In addition, the 2009 Sarychev Peak eruption co-injected hydrogen chloride (HCl) alongside SO2, whose potential stratospheric chemistry impacts have not been investigated to date. We present a study of the stratospheric SO2–particle–HCl processing and impacts following Sarychev Peak eruption, using the Community Earth System Model version 1.0 (CESM1) Whole Atmosphere Community Climate Model (WACCM) – Community Aerosol and Radiation Model for Atmospheres (CARMA) sectional aerosol microphysics model (with no a priori assumption on particle size). The Sarychev Peak 2009 eruption injected 0.9 Tg of SO2 into the upper troposphere and lower stratosphere (UTLS), enhancing the aerosol load in the Northern Hemisphere. The post-eruption evolution of the volcanic SO2 in space and time are well reproduced by the model when compared to Infrared Atmospheric Sounding Interferometer (IASI) satellite data. Co-injection of 27 Gg HCl causes a lengthening of the SO2 lifetime and a slight delay in the formation of aerosols, and acts to enhance the destruction of stratospheric ozone and mono-nitrogen oxides (NOx) compared to the simulation with volcanic SO2 only. We therefore highlight the need to account for volcanic halogen chemistry when simulating the impact of eruptions such as Sarychev on stratospheric chemistry. The model-simulated evolution of effective radius (reff) reflects new particle formation followed by particle growth that enhances reff to reach up to 0.2 µm on zonal average. Comparisons of the model-simulated particle number and size distributions to balloon-borne in situ stratospheric observations over Kiruna, Sweden, in August and September 2009, and over Laramie, USA, in June and November 2009 show good agreement and quantitatively confirm the post-eruption particle enhancement. We show that the model-simulated SAOD is consistent with that derived from the Optical Spectrograph and InfraRed Imager System (OSIRIS) when both the saturation bias of OSIRIS and the fact that extinction profiles may terminate well above the tropopause are taken into account. Previous modelling studies (involving assumptions on particle size) that reported agreement with (biased) post-eruption estimates of SAOD derived from OSIRIS likely underestimated the climate impact of the 2009 Sarychev Peak eruption.

The major volcanic eruption of Mount Pinatubo in 1991 has been shown to have significant effects on stratospheric chemistry and ozone depletion even at midlatitudes. Since then, only moderate but recurrent volcanic eruptions have modulated the stratospheric aerosol loading and are assumed to be one cause for the reported increase in the global aerosol content over the past 15 years. This particularly enhanced aerosol context raises questions about the effects on stratospheric chemistry which depend on the latitude, altitude and season of injection. In this study, we focus on the midlatitude Sarychev volcano eruption in June 2009, which injected 0.9 Tg of sulfur dioxide (about 20 times less than Pinatubo) into a lower stratosphere mainly governed by high-stratospheric temperatures. Together with in situ measurements of aerosol amounts, we analyse high-resolution in situ and/or remote-sensing observations of NO2, HNO3 and BrO from balloon-borne infrared and UV–visible spectrometers launched in Sweden in August–September 2009. It is shown that differences between observations and three-dimensional (3-D) chemistry-transport model (CTM) outputs are not due to transport calculation issues but rather reflect the chemical impact of the volcanic plume below 19 km altitude. Good measurement–model agreement is obtained when the CTM is driven by volcanic aerosol loadings derived from in situ or space-borne data. As a result of enhanced N2O5 hydrolysis in the Sarychev volcanic aerosol conditions, the model calculates reductions of ∼ 45 % and increases of ∼ 11 % in NO2 and HNO3 amounts respectively over the August–September 2009 period. The decrease in NOx abundances is limited due to the expected saturation effect for high aerosol loadings. The links between the various chemical catalytic cycles involving chlorine, bromine, nitrogen and HOx compounds in the lower stratosphere are discussed. The increased BrO amounts (∼ 22 %) compare rather well with the balloon-borne observations when volcanic aerosol levels are accounted for in the CTM and appear to be mainly controlled by the coupling with nitrogen chemistry rather than by enhanced BrONO2 hydrolysis. We show that the chlorine partitioning is significantly controlled by enhanced BrONO2 hydrolysis. However, simulated effects of the Sarychev eruption on chlorine activation are very limited in the high-temperature conditions in the stratosphere in the period considered, inhibiting the effect of ClONO2 hydrolysis. As a consequence, the simulated chemical ozone loss due to the Sarychev aerosols is low with a reduction of −22 ppbv (−1.5 %) of the ozone budget around 16 km. This is at least 10 times lower than the maximum ozone depletion from chemical processes (up to −20 %) reported in the Northern Hemisphere lower stratosphere over the first year following the Pinatubo eruption. This study suggests that moderate volcanic eruptions have limited chemical effects when occurring at midlatitudes (restricted residence times) and outside winter periods (high-temperature conditions). However, it would be of interest to investigate longer-lasting tropical volcanic plumes or sulfur injections in the wintertime low-temperature conditions.

On coral reefs, depth and gradients related to depth (e.g. light and wave exposure) influence the composition of fish communities. However, most studies focus only on emergent reefs that break the sea surface in shallow waters (

Urban food producers play an important role in food systems around the world. Understanding the factors that may influence producers’ intention to produce food is important to predict their behavior. The purpose of this study was to examine one city in the United States and describe factors that may influence the intention of urban food producers to continue farming in urban settings, and specifically identify factors that influence attitude, perceived behavioral control, and subjective norms toward urban food production. The study followed a qualitative design using semi-structured interviews. The results revealed factors that can both positively and negatively influence Columbus urban food producers’ intention to continue farming in urban settings. Perceived complexity can negatively influence attitude and hinder food producers’ intention to continue urban food production while subjective norms, influenced by peer growers and family members, may heighten intention to continue urban food production. The findings also revealed personal characteristics, such as education and access to resources, that may enhance perceived behavioral control. The findings can be used by various regions of the world to develop urban food production. Implications expose opportunities for urban food producers, extension, institutions, and future researchers to address existing complexities, develop educational programs, and enhance social ties to provide support for farming in urban settings.

Ambrym Volcano (Vanuatu, southwest Pacific) is one of the largest sources of continuous volcanic emissions worldwide. As well as releasing SO2 that is oxidized to sulfate, volcanic plumes in the troposphere are shown to undergo reactive halogen chemistry whose atmospheric impacts have been little explored to date. Here, we investigate with the regional-scale model CCATT-BRAMS (Coupled Chemistry Aerosol-Tracer Transport model, Brazilian developments on the Regional Atmospheric Modeling System, version 4.3) the chemical processing in the Ambrym plume and the impact of this volcano on the atmospheric chemistry on both local and regional scales. We focus on an episode of extreme passive degassing that occurred in early 2005 and for which airborne DOAS (differential optical absorption spectroscopy) measurements of SO2 and BrO columns in the near-downwind plume between 15 and 40 km from the vents have been reported. The model was developed to include reactive halogen chemistry and a volcanic emission source specific to this extreme degassing event. In order to test our understanding of the volcanic plume chemistry, we performed very high-resolution (500 m × 500 m) simulations using the model nesting grid capability and compared each DOAS measurement to its temporally and spatially interpolated model counterpart “point-by-point”. Simulated SO2 columns show very good quantitative agreement with the DOAS observations, suggesting that the plume direction as well as its dilution in the near-downwind plume are well captured. The model also reproduces the salient features of volcanic chemistry as reported in previous work, such as HOx and ozone depletion in the core of the plume. When a high-temperature chemistry initialization is included, the model is able to capture the observed BrO ∕ SO2 trend with distance from the vent. The main discrepancy between observations and model is the bias between the magnitudes of observed and simulated BrO columns that ranges from 60 % (relative to the observations) for the transect at 15 km to 14 % for the one at 40 km from the vents. We identify total in-plume depletion of ozone as a limiting factor for the partitioning of reactive bromine into BrO in the near-source (concentrated) plume under these conditions of extreme emissions and low background ozone concentrations (15 ppbv). Impacts of Ambrym in the southwest Pacific region were also analyzed. As the plume disperses regionally, reactive halogen chemistry continues on sulfate aerosols produced by SO2 oxidation and promotes BrCl formation. Ozone depletion is weaker than on the local scale but still between 10 and 40 % in an extensive region a few thousands of kilometers from Ambrym. The model also predicts the transport of bromine to the upper troposphere and stratosphere associated with convection events. In the upper troposphere, HBr is re-formed from Br and HO2. Comparison of SO2 regional-scale model fields with OMI (Ozone Monitoring Instrument) satellite SO2 fields confirms that the Ambrym SO2 emissions estimate based on the DOAS observations used here is realistic. The model confirms the potential of volcanic emissions to influence the oxidizing power of the atmosphere: methane lifetime (calculated with respect to OH and Cl) is increased overall in the model due to the volcanic emissions. When considering reactive halogen chemistry, which depletes HOx and ozone, the lengthening of methane lifetime with respect to OH is increased by a factor of 2.6 compared to a simulation including only volcanic SO2 emissions. Cl radicals produced in the plume counteract 41 % of the methane lifetime lengthening due to OH depletion. Including the reactive halogen chemistry in our simulation also increases the lifetime of SO2 in the plume with respect to oxidation by OH by 36 % compared to a simulation including only volcanic SO2 emissions. This study confirms the strong influence of Ambrym emissions during the extreme degassing event of early 2005 on the composition of the atmosphere on both local and regional scales. It also stresses the importance of considering reactive halogen chemistry when assessing the impact of volcanic emissions on climate.

Observations from CMET (Controlled Meteorological) balloons are analysed to provide insights into tropospheric meteorological conditions (temperature, humidity, wind) around Svalbard, European High Arctic. Five Controlled Meteorological (CMET) balloons were launched from Ny-Ålesund in Svalbard (Spitsbergen) over 5–12 May 2011 and measured vertical atmospheric profiles over coastal areas to both the east and west. One notable CMET flight achieved a suite of 18 continuous soundings that probed the Arctic marine boundary layer (ABL) over a period of more than 10 h. Profiles from two CMET flights are compared to model output from ECMWF Era-Interim reanalysis (ERA-I) and to a high-resolution (15 km) Arctic System Reanalysis (ASR) product. To the east of Svalbard over sea ice, the CMET observed a stable ABL profile with a temperature inversion that was reproduced by ASR but not captured by ERA-I. In a coastal ice-free region to the west of Svalbard, the CMET observed a stable ABL with strong wind shear. The CMET profiles document increases in ABL temperature and humidity that are broadly reproduced by both ASR and ERA-I. The ASR finds a more stably stratified ABL than observed but captured the wind shear in contrast to ERA-I. Detailed analysis of the coastal CMET-automated soundings identifies small-scale temperature and humidity variations with a low-level flow and provides an estimate of local wind fields. We demonstrate that CMET balloons are a valuable approach for profiling the free atmosphere and boundary layer in remote regions such as the Arctic, where few other in situ observations are available for model validation.

The reactive uptake of HOBr onto halogen-rich aerosols promotes conversion of Br−(aq) into gaseous reactive bromine (incl. BrO) with impacts on tropospheric oxidants and mercury deposition. However, experimental data quantifying HOBr reactive uptake on tropospheric aerosols is limited, and reported values vary in magnitude. This study introduces a new evaluation of HOBr reactive uptake coefficients in the context of the general acid-assisted mechanism. We emphasise that the termolecular kinetic approach assumed in numerical model studies of tropospheric reactive bromine chemistry to date is strictly only valid for a specific pH range and, according to the general acid-assisted mechanism for HOBr, the reaction kinetics becomes bimolecular and independent of pH at high acidity. This study reconciles for the first time the different reactive uptake coefficients reported from laboratory experiments. The re-evaluation confirms HOBr reactive uptake is rapid on moderately acidified sea-salt aerosol (and slow on alkaline aerosol), but predicts very low reactive uptake coefficients on highly acidified submicron particles. This is due to acid-saturated kinetics combined with low halide concentrations induced by both acid-displacement reactions and the dilution effects of H2SO4(aq). A mechanism is thereby proposed for reported Br enhancement (relative to Na) in H2SO4-rich submicron particles in the marine environment. Further, the fact that HOBr reactive uptake on H2SO4-acidified supra-micron particles is driven by HOBr+Br− (rather than HOBr+Cl−) indicates self-limitation via decreasing γHOBr once aerosol Br- is converted into reactive bromine. First predictions of HOBr reactive uptake on sulfate particles in halogen-rich volcanic plumes are also presented. High (accommodation limited) HOBr+Br- uptake coefficient in concentrated (> 1 μmol mol−1 SO2) plume environments supports potential for rapid BrO formation in plumes throughout the troposphere. However, reduced HOBr reactive uptake may reduce the rate of BrO cycling in dilute plumes in the lower troposphere. In summary, our re-evaluation of HOBr kinetics provides a new framework for the interpretation of experimental data and suggests that the reactive uptake of HOBr on H2SO4-acidified particles is substantially overestimated in current numerical models of BrO chemistry in the troposphere.

Volcanic emissions present a source of reactive halogens to the troposphere, through rapid plume chemistry that converts the emitted HBr to more reactive forms such as BrO. The nature of this process is poorly quantified, yet is of interest in order to understand volcanic impacts on the troposphere, and infer volcanic activity from volcanic gas measurements (i.e. BrO / SO2 ratios). Recent observations from Etna report an initial increase and subsequent plateau or decline in BrO / SO2 ratios with distance downwind. We present daytime PlumeChem model simulations that reproduce and explain the reported trend in BrO / SO2 at Etna including the initial rise and subsequent plateau. Suites of model simulations also investigate the influences of volcanic aerosol loading, bromine emission, and plume–air mixing rate on the downwind plume chemistry. Emitted volcanic HBr is converted into reactive bromine by autocatalytic bromine chemistry cycles whose onset is accelerated by the model high-temperature initialisation. These rapid chemistry cycles also impact the reactive bromine speciation through inter-conversion of Br, Br2, BrO, BrONO2, BrCl, HOBr. We predict a new evolution of Br speciation in the plume. BrO, Br2, Br and HBr are the main plume species near downwind whilst BrO and HOBr are present further downwind (where BrONO2 and BrCl also make up a minor fraction). BrNO2 is predicted to be only a relatively minor plume component. The initial rise in BrO / SO2 occurs as ozone is entrained into the plume whose reaction with Br promotes net formation of BrO. Aerosol has a modest impact on BrO / SO2 near-downwind (< ~6 km, ~10 min) at the relatively high loadings considered. The subsequent decline in BrO / SO2 occurs as entrainment of oxidants HO2 and NO2 promotes net formation of HOBr and BrONO2, whilst the plume dispersion dilutes volcanic aerosol so slows the heterogeneous loss rates of these species. A higher volcanic aerosol loading enhances BrO / SO2 in the (> 6 km) downwind plume. Simulations assuming low/medium and high Etna bromine emissions scenarios show that the bromine emission has a greater influence on BrO / SO2 further downwind and a modest impact near downwind, and show either complete or partial conversion of HBr into reactive bromine, respectively, yielding BrO contents that reach up to ~50 or ~20% of total bromine (over a timescale of a few 10 s of minutes). Plume–air mixing non-linearly impacts the downwind BrO / SO2, as shown by simulations with varying plume dispersion, wind speed and volcanic emission flux. Greater volcanic emission flux leads to lower BrO / SO2 ratios near downwind, but also delays the subsequent decline in BrO / SO2, and thus yields higher BrO / SO2 ratios further downwind. We highlight the important role of plume chemistry models for the interpretation of observed changes in BrO / SO2 during/prior to volcanic eruptions, as well as for quantifying volcanic plume impacts on atmospheric chemistry. Simulated plume impacts include ozone, HOx and NOx depletion, the latter converted into HNO3. Partial recovery of ozone occurs with distance downwind, although cumulative ozone loss is ongoing over the 3 h simulations.

Universities are being called upon to internationalize curriculum as the need for a globally competent workforce increases. Without globally-competent faculty, international integration within higher education cannot occur. Literature indicates that participation in short-term international agricultural education experiences is important to increasing agricultural faculty members’ cultural awareness. However, the best way to design and implement such experiences for faculty is uncharted. The purpose of the study was to identify best practices for facilitating a short-term international agricultural education experience for faculty in the agricultural and life sciences that encouraged learning, discussion, and reflection leading faculty to further integrate international perspectives in their agricultural courses in the U.S. Through a qualitative research design, reflective observations and statements from a planning team conducting a short-term international agricultural education experience in Ecuador were used to provide a thick, rich description of the successes/challenges faced while designing and implementing the experience. The results provided a list of best practices future planning team members can use to emphasize learning before, during, and after a short-term international agricultural education experience for faculty.

Understanding patterns in species richness and diversity over environmental gradients (such as altitude and depth) is an enduring component of ecology. As most biological communities feature few common and many rare species, quantifying the presence and abundance of rare species is a crucial requirement for analysis of these patterns. Coral reefs present specific challenges for data collection, with limitations on time and site accessibility making efficiency crucial. Many commonly used methods, such as line intercept transects (LIT), are poorly suited to questions requiring the detection of rare events or species. Here, an alternative method for surveying reef-building corals is presented; the point count transect (PCT). The PCT consists of a count of coral colonies at a series of sample stations, located at regular intervals along a transect. In contrast the LIT records the proportion of each species occurring under a transect tape of a given length. The same site was surveyed using PCT and LIT to compare species richness estimates between the methods. The total number of species increased faster per individual sampled and unit of time invested using PCT. Furthermore, 41 of the 44 additional species recorded by the PCT occurred ≤ 3 times, demonstrating the increased capacity of PCT to detect rare species. PCT provides a more accurate estimate of local-scale species richness than the LIT, and is an efficient alternative method for surveying reef corals to address questions associated with alpha-diversity, and rare or incidental events.

In the structure of the title compound, [Zn(C8H6NO4)2(C3H10N2)2], the ZnII atom is located on a center of symmetry with one independent Zn—O distance of 2.199 (2) Å, and two Zn—N distances of 2.157 (2) and 2.144 (2) Å. The overall coordination geometry around the ZnII atom is octahedral. Several types of hydrogen-bonding interactions are evident. Both intramolecular [2.959 (3) Å] and intermolecular [3.118 (3) and 3.124 (3) Å interactions occur between the O atoms of the acetate group and the amino N atoms, and weak intermolecular C—H—O interactions involving the nitro groups, leading to an extended chain of the molecules aligned along the ac plane.

Reusable learning objects are short, self-contained, digital learning activities that can be valuable tools for sharing information. This 4-page fact sheet provides a brief synopsis of what reusable learning objects are and how to create them for use in an educational setting. Written by Jessica L. Gouldthorpe, Amy Harder, T. Grady Roberts, and Nicole Stedman, and published by the UF Department of Agricultural Education and Communication, April 2013. http://edis.ifas.ufl.edu/wc140

This paper presents new results showing the application of polyomino-based subarrays to limited field of view and wideband, wide-angle scanning. This technology can reduce the number of phase controls in arrays used for limited sector coverage or the number of time delay devices for wideband radar or communications, and so can reduce the cost of space-based active arrays. We concentrate on the wideband application. Results are presented by comparing the gain and peak sidelobe results of irregular polyomino subarray-based arrays with those of rectangular subarrays. It is shown that using irregular polyomino subarrays can result in a major decrease in sidelobes while presenting, in most cases, only a few tenths of a dB gain reduction compared to rectangular subarrays.