bluuebunny/crossref_metadata_2025 huggingface dataset:
Les réformes de l'aide internationale américaine au banc d'essai : le cas afghan
Authors: Frumin Amy B. , ae Poortère Aurélie
Published: January 2013

En mai 2010, l’équipe du président Obama a laissé filtrer un avant-projet de la Directive d’étude présidentielle 7 (PSD 7), intitulé « une nouvelle feuille de route pour le développement mondial ». La PSD 7 en appelle à une politique de développement réfléchie, une nouvelle approche et restructuration de l’aide internationale. Vu du terrain, une réforme est la bienvenue. Toutefois, une réforme de fond implique nécessairement une redéfinition de la relation entre le Congrès et USAID. Si cet article plaide pour une telle réforme, il met aussi l’accent sur l’urgence d’une réforme des acteurs et des activités de développement sur le terrain, en priorité en Afghanistan. L’auteur recommande la mise en œuvre en Afghanistan d’un des principes contenus dans chacun des piliers de la réforme préconisée par la PSD 7. Cela permettrait non seulement de démontrer la viabilité de ces piliers, mais aussi de stabiliser la situation en Afghanistan.
Privacy and Security for Virtual Communities and Social Networks
Authors: Michaelides Georgios , Hosszú Gábor
Published: January 2013

The importance of the virtual communities’ privacy and security problems comes into prominence by the rapid development of online social networks. This article presents the multiple threats currently plaguing the virtual world, Internet privacy risks, and recommendations and countermeasures to avoid such problems. New generations of users feel comfortable publishing their personal information and narrating their lives. They are often unaware how vulnerable the data in their public profiles are, which a large audience daily accesses. A so-called digital friendship is built among them. Such commercial and social pressures have led to a number of privacy and security risks for social network members. The article presents the most important vulnerabilities and suggests protection methods and solutions that can be utilized according to the threat. Lastly, the authors introduce the concept of a privacy-friendly virtual community site, named CWIW, where privacy methods have been implemented for better user protection.
The Psychology of Trolling and Lurking
Authors: Bishop Jonathan
Published: January 2013

The rise of social networking services have furthered the proliferation of online communities, transferring the power of controlling access to content from often one person who operates a system (sysop), which they would normally rely on, to them personally. With increased participation in social networking and services come new problems and issues, such as trolling, where unconstructive messages are posted to incite a reaction, and lurking, where persons refuse to participate. Methods of dealing with these abuses included defriending, which can include blocking strangers. The Gamified Flow of Persuasion model is proposed, building on work in ecological cognition and the participation continuum, the chapter shows how all of these models can collectively be used with gamification principles to increase participation in online communities through effective management of lurking, trolling, and defriending.
Multiple Perspectives for the Study of Teaching
Authors: Salloum Sara
Published: January 2013

This chapter outlines a framework that characterizes science teachers’ practical-moral knowledge utilizing the Aristotelian concept of phronesis/practical wisdom. The meaning of phronesis is further explicated and its relevance to science education are outlined utilizing a virtue-based view of knowledge and practical hermeneutics. First, and to give a background, assumptions about teacher knowledge from a constructivist and sociocultural perspective are outlined. Second, the Aristotelian notion of phronesis (practical wisdom) is explicated, especially in terms of how it differs from other characterizations of practical knowledge in science education and how it relates to practical-moral knowledge. Finally, the authors discuss how the very nature of such practical-moral knowledge makes it ambiguous and hard to articulate, and therefore, a hermeneutic model that explores teachers’ practical-moral knowledge indirectly by investigating teachers’ commitments, interpretations, actions, and dialectic interactions is outlined. Implications for research and teacher education are outlined. Empirical examples are used to demonstrate certain points. A virtue-based view of knowledge is not meant to replace others, but as a means to enrich the understandings of the complexity of teacher knowledge and to enhance the effectiveness of teacher educators.
Opening Both Eyes
Authors: Clary Renee M. , Wandersee James H.
Published: January 2013

The focus of this chapter is an exploration of integrated geology and biology learning—from past to present. The chapter explains why active and integrated geological and biological learning became the lodestar of the authors’ decade-long EarthScholars Research Group’s research program. The authors argue that using an active and integrated geobiological pedagogical approach when teaching geology or biology provides natural opportunities for students to learn and do authentic scientific inquiry in a manner similar to how contemporary scientists conduct their work. The authors further review research that concerns the active, integrated geobiological science learning approach—in middle school, secondary, and college classrooms, laboratories, and field studies. The authors favor a gradual course transition to this pedagogy, while highlighting the advantages of adopting such an approach—both for teachers and students. Finally, the authors conclude the chapter with challenges and future directions in the design of active, integrated geobiological science learning environments.
Rooted in Teaching
Authors: Gross Lisa A. , James Joy , Frauman Eric
Published: January 2013

Research in Environmental Socialization (ES) and the impact of significant life experiences suggest that childhood play in outdoor environments shape later adult activities or career interests. Few studies have investigated how childhood experiences influence curricular interests of preservice and inservice teachers. This preliminary study examines what ES factors of teachers raised in rural and/or non-rural environments reveal about their interests in science topics and field-based learning opportunities. Results suggest that teachers growing up in rural areas were slightly less interested than non-rural teachers in field-based learning and expressed less experience with environmental education. Teachers with more ES experiences (e.g., played in the woods, built forts) expressed greater interest in science-related topics than those who had indicated fewer experiences. Rural teachers tended to have more ES experiences than non-rural teachers. The authors discuss how environmental socialization factors influence teacher preference for curricular programs specific to environmental and ecological topics and raise questions about the changing environmental socialization experiences of preservice and novice teachers.
Next Generation Science Assessment
Authors: Lyon Edward G.
Published: January 2013

The recent release of science education documents such as A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (National Research Council, 2012) marks the transition into a new generation of science education. This transition necessitates a close look at how pre-college science teachers will assess a diverse group of students in ways that are consistent with science education reform. In this chapter, the authors identify current research in science assessment and employ assessment coherence, assessment use, and assessment equity as guiding principles to address the challenges of putting science assessment research into classroom practice. To exemplify these challenges, they describe a study where a research instrument designed to measure scientific reasoning skills was translated into a high school science classroom assessment. The goal of this chapter is to stimulate conversation in the science education community (researchers, assessment developers, teacher educators, administrators, and classroom teachers) about how to put science assessment research successfully into practice and to describe what next steps need to be taken, particularly around assessing diverse student populations.
The Financial Related Analysis on Sales Management and Human Resources by Means of BI Type Solutions
Authors: Serbanescu Luminita , Radulescu Magdalena
Published: January 2013

All companies need information in order to make decisions. There is usually too much data spread in the IT systems of the company, but transforming the data into information that can be analyzed in order to make decisions is a difficult process. Considering the demands imposed by the knowledge society, each organization strives to become an intelligent organization and, by the means of new and innovative Business Intelligence(BI) strategy, to gain a market competition advantage. The new BI era integrates information into the decision process through the means of decision services, relates business processes to business rules that may be changed at any time, and integrates BI benefits to capabilities provided by teamwork, cooperation, and business process management. In this article, the authors present a BI solution, implemented through QlikView Application, thanks to which it is possible to analyse the employee expenses and for management sales.
Information Technology and Firm Innovations
Authors: Datta Avimanyu
Published: January 2013

This paper provides a framework comprising of research agenda explicating the relations between IT Capability and Firm Innovation. Firm innovation is conceptualized as a combination of three constructs: networks, capabilities (absorptive capacity), and commercialization of innovations (CI). These three constructs have received a very lukewarm response from the IS research community. Inclusion of these three constructs, and examining how IT- capability affects the relationships between these constructs, is essential to examining the role of IT in innovation at the firm-level. Five research agendas are identified.
An Action Research
Authors: Chien Chih-Feng , Moghadasian Zahra
Published: January 2013

This article reports an action research, conducted in an undergraduate course, Second Language Acquisition and Development, in a 3-way blended learning (BL) environment—face-to-face (F2F), an online learning system (eLearning), and Second Life (SL). The study was the result of a joint project between a university in America and one in Hong Kong. Data collected from the American students were included in this study. The purposes of this action research is to: 1) monitor BL course and provide suggestions for future courses, and 2) investigate if students’ time spent in eLearning and the number of discussion posts impact students’ achievement. This action research provides suggestions for improving application of 3-way BL in future courses in terms of course design, instructor preparation and online grading.
Artificial Neural Network Simulated Elman Models for Predicting Shelf Life of Processed Cheese
Authors: Goyal Sumit , Goyal Gyanendra Kumar
Published: January 2013

Elman artificial neural network models with single and multilayer for predicting shelf life of processed cheese stored at 7-8ºC were developed. Input parameters were: Body & texture, aroma & flavour, moisture, and free fatty acid, while sensory score was output parameter. Bayesian regularization was training algorithm for the models. The network was trained up to 100 epochs, and neurons in each hidden layers varied from 1 to 20. Transfer function for hidden layer was tangent sigmoid, while for the output layer it was pure linear function. Mean Square Error, Root Mean Square Error, Coefficient of Determination and Nash - Sutcliffo Coefficient were used for comparing the prediction ability of the developed models. Elman model with combination of 4-17-17-1 performed significantly well for predicting the shelf life of processed cheese stored at 7-8º C.
The Position of Rough Set in Soft Set
Authors: Herawan Tutut
Published: January 2013

In this paper, the author presents the concept of topological space that must be used to show a relation between rough set and soft set. There are two main results presented; firstly, a construction of a quasi-discrete topology using indiscernibility (equivalence) relation in rough set theory is described. Secondly, the paper describes that a “general” topology is a special case of soft set. Hence, it is concluded that every rough set can be considered as a soft set.
Representing, Modeling and Engineering a Collaborative Supply Chain Management Platform
Authors: Wautelet Yves
Published: January 2013

Global optimization among partners of a supply chain is a trend often found in scientific literature. To achieve such a result, technological tools to collect suitable information within shortest delays are required. Devices such as RFID or GPS positioning systems deliver real-time information on material flows. However, data fragments need to be integrated in a global information sharing system where each of the involved actors can perform computations as well as operations to take autonomous action and manage resources at best. In this perspective, the paper presents a research aimed to build an e-collaborative software system for outbound logistic actors. Advanced knowledge representation models are used, notably a framework driven by the core services provided by the involved actors and structured using the classical three decision layers. The actor’s rationale is then detailed which further leads to the design of a multi-agent system. The proposal is validated using a critical success factors framework for IT evaluation in SCM.
A Refinement of the Classical Order Point Model
Authors: Moeeni Farhad , Replogle Stephen , Chaudhury Zariff , Syamil Ahmad
Published: January 2013

Factors such as demand volume and replenishment lead time that influence production and inventory control systems are random variables. Existing inventory models incorporate the parameters (e.g., mean and standard deviation) of these statistical quantities to formulate inventory policies. In practice, only sample estimates of these parameters are available. The estimates are subject to sampling variation and hence are random variables. Whereas the effect of sampling variability on estimates of parameters are in general well known in statistics literature, literature on inventory control policies has largely ignored the potential effect of sampling variation on the validity of the inventory models. This paper investigates the theoretical effect of sampling variability and develops theoretically sound inventory models that can be effectively used in different inventory policies.
WorldCupinion Experiences with an Android App for Real-Time Opinion Sharing During Soccer World Cup Games
Authors: Schleicher Robert , Shirazi Alireza Sahami , Rohs Michael , Kratz Sven , Schmidt Albrecht
Published: January 2013

Mobile devices are increasingly used in social networking applications and research. So far, there is little work on real-time emotion or opinion sharing in large loosely coupled user communities. One potential area of application is the assessment of widely broadcasted television (TV) shows. The idea of connecting non-collocated TV viewers via telecommunication technologies is referred to as Social TV. Such systems typically include set-top boxes for supporting the collaboration. In this work the authors investigated whether mobile phones can be used as an additional channel for sharing opinions, emotional responses, and TV-related experiences in real-time. To gain insight into this area, an Android app was developed for giving real-time feedback during soccer games and to create ad hoc fan groups. This paper presents results on rating activity during games and discusses experiences with deploying this app over four weeks during soccer World Cup. In doing so, challenges and opportunities faced are highlighted and an outlook on future work in this area is given.
SGVis
Authors: Morrison Alistair , Chalmers Matthew
Published: January 2013

The recent rise in popularity of ‘app store’ markets on a number of different mobile platforms has provided a means for researchers to run worldwide trials of ubiquitous computing (ubicomp) applications with very large numbers of users. This opportunity raises challenges, however, as more traditional methods of running trials and gathering data for analysis might be infeasible or fail to scale up to a large, globally-spread user base. SGVis is a data analysis tool designed to aid ubicomp researchers in conducting trials in this manner. This paper discusses the difficulties involved in running large scale trials, explaining how these led to recommendations on what data researchers should log, and to design choices made in SGVis. The authors outline several methods of use and why they help with challenges raised by large scale research. A means of categorising users is also described that could aid in data analysis and management of a trial with very large numbers of participants. SGVis has been used in evaluating several mass-participation trials, involving tens of thousands of users, and several use cases are described that demonstrate its utility.
Balancing Awareness and Interruption in Mobile Patrol using Context-Aware Notification
Authors: Streefkerk Jan Willem , McCrickard D. Scott , van Esch-Bussemakers Myra P. , Neerincx Mark A.
Published: January 2013

In mobile computing, a fundamental problem is maintaining awareness of the environment and of information presented as messages on a mobile device. In mobile police patrols, officers need to pay attention to their direct environment and stay informed of incidents elsewhere. To prevent unwanted interruption, a context-aware notification system adapts the timing and appearance of incident messages, based on user activity (available, in transit, or busy) and message priority (high, normal, or low). The authors evaluated the benefits and costs of adaptive notification compared to three uniform notification styles (presenting full messages, postponing messages or presenting indicators). Thirty-two trained student participants used a prototype notification system in a controlled mobile patrol task. The results were validated in a follow-up study with twenty-four police officers.
Lessons Learned from Large-Scale User Studies
Authors: Ferreira Denzil , Kostakos Vassilis , Dey Anind K.
Published: January 2013

User studies with mobile devices have typically been cumbersome, since researchers have had to recruit participants, hand out or configure devices, and offer incentives and rewards. The increasing popularity of application stores has allowed researchers to use such mechanisms to recruit participants and conduct large-scale studies in authentic settings with relatively little effort. Most researchers who use application stores do not consider the side-effects or biases that such an approach may introduce. The authors summarize prior work that has reported experiences from using application stores as a recruiting, distribution and study mechanism, and also present a case study of a 4-week long study using the Android Market to deploy an application to over 4000 users that collected data on their mobile phone charging habits. The authors synthesize their own experiences with prior reported findings to discuss the challenges, advantages, limitations and considerations of using application stores as a recruitment and distribution approach for conducting large-scale studies.
A Scalable Multi-Tenant Architecture for Business Process Executions
Authors: Pathirage Milinda , Perera Srinath , Kumara Indika , Weerasiri Denis , Weerawarana Sanjiva
Published: January 2013

Cloud computing, as a concept, promises cost savings to end-users by letting them outsource their non-critical business functions to a third-party in pay-as-you-go style. However, to enable economic pay-as-you-go services, the end-users need Cloud middleware that maximizes sharing and support near-zero cost for unused applications. Multi-tenancy, which let multiple tenants to share a single application instance securely, is a key enabler for building such a middleware. On the other hand, Business processes capture Business logic of organizations in an abstract and reusable manner, and hence play a key role in most organizations. This paper presents the design and architecture of a scalable Multi-tenant Workflow engine while discussing in detail the potential use cases of such architecture. Primary contributions of this paper are motivating workflow multi-tenancy, and the design and implementation of a scalable multi-tenant workflow engine that enables multiple tenants to run their workflows securely within the same workflow engine instance without modifications to the workflows. Furthermore, the workflow engine supports process sharing and process variability across the tenants and discusses its ramifications.
Lightweight Wireless Web Service Communication Through Enhanced Caching Mechanisms
Authors: Papageorgiou Apostolos , Schatke Marius , Schulte Stefan , Steinmetz Ralf
Published: January 2013

Reducing the size of the wirelessly transmitted data during the invocation of third-party Web services is a worthwhile goal of many mobile application developers. Among many adaptation mechanisms that can be used for the mediation of such Web service invocations, the automated enhancement of caching mechanisms is a promising approach that can spare the re-transmission of entire content fields of the exchanged messages. However, it is usually impeded by technological constraints and by various other factors, such as the inherent risk of using responses that are not fresh, i.e., are not up-to-date. This paper presents the roadmap, the most important technical and algorithmic details, and a thorough evaluation of the first solution for generically and automatically enriching the communication with any third-party Web service in a way that cached responses can be exploited while a freshness of 100% is maintained.
Renal Tuberculosis in the Modern Era
Authors: Daher Elizabeth De Francesco , da Silva Junior Geraldo Bezerra , Barros Elvino José Guardão
Published: January 2013

Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis. The disease remains as an important public health problem in developing countries. Extrapulmonary TB became more common with the advent of infection with human immunodeficiency virus and by the increase in the number of organ transplantation, which also leads to immunosuppression of thousand of persons. Urogenital TB represents 27% of extrapulmonary cases. Renal involvement in TB can be part of a disseminated infection or a localized genitourinary disease. Renal involvement by TB infection is underdiagnosed in most health care centers. Most patients with renal TB have sterile pyuria, which can be accompanied by microscopic hematuria. The diagnosis of urinary tract TB is based on the finding of pyuria in the absence of common bacterial infection. The first choice drugs include isoniazide, rifampicin, pirazinamide, ethambutol, and streptomycin. Awareness of renal TB is urgently needed by physicians for suspecting this disease in patients with unexplained urinary tract abnormalities, mainly in those with any immunosuppression and those coming from TB-endemic areas.
Comparison of 99mTc- Ethylene Dicysteine and 99mTc-Dimercaptosuccinic Acid Scintigraphy for the Evaluation of Cortical Scarring and Differential Renal Function in Children with Recurrent Urinary Tract Infection
Authors: Rao KLN , Mittal BR , Raja Senthil , Pareek Vipul , Singh Baljinder , Sharma Sarika
Published: January 2013

Introduction

Urinary tract infection (UTI) is the most common and severe bacterial infection in children. Renal scarring and associated deterioration in the differential renal function is a frequent finding. Scarring may occur even in asymptomatic patients without vesicoureteric reflux.

Materials and methods

Fifty-three children (43 M:10 F, mean age:5.3 years; range 2-10 years) with evidence of recurrent UTI were enrolled in the study. Patients with duplex or crossed fused ectopic kidneys and with acute or chronic renal failure were excluded from the study protocol. Each patient underwent 99mTc-DMSA and 99mTc-EC renal scintigraphy within a period of 2 weeks.

Results

Analysis of results was performed by comparing the diagnostic accuracy of the summed 99mTc-EC and 99mTc-DMSA images for the detection of renal cortical scars and correlation (linear regression analysis) between the two renal scintigraphic procedures for the estimation of differential renal function. 99mTc-DMSA imaging demonstrated scarring in 41 kidneys whereas 99mTc-EC scintigraphy revealed scarring in 29/41 kidneys only. The percentage function of both kidneys with 99mTc-EC and 99mTc-DMSA showed good correlation. The r2 for left kidney was 0.95 and for right kidney was 0.94.

Conclusion

99mTc-EC scintigraphy has low sensitivity (70%) for the detection of cortical scarring as compared to 99mTc-DMSA (100%) renal imaging. On the hand, 99mTc-DMSA static imaging gives good estimate for the DRF and the values are in good agreement with the corresponding values derived from dynamic 99mTc-EC scanning.

How to cite this article

Raja S, Pareek V, Singh B, Sharma S, Rao KLN, Mittal BR. Comparison of 99mTc-Ethylene Dicysteine and 99mTc-Dimercaptosuccinic Acid Scintigraphy for the Evaluation of Cortical Scarring and Differential Renal Function in Children with Recurrent Urinary Tract Infection. J Postgrad Med Edu Res 2012;46(4):183-186.
Steroid Responsive Parenchymal Lung Involvement and Acute Renal Failure in a Patient with Relapsing Polychondritis
Authors: Lal Anupam , Singh Surjit , Kumar Susheel , Sharma Aman , Goyal Palvi , Law Arjun D
Published: January 2013

Relapsing polychondritis is a multisystem disorder affecting cartilaginous structures like ear, nose, laryngotracheal tree and proteogylcan rich structures like eyes. Kidney involvement has also been reported in the absence of associated conditions like SLE and vasculitides but parenchymal lung involvement has not been reported in the English literature. One such case of relapsing polychondritis who had parenchymal lung involvement with respiratory failure, renal failue and pancytopenia is described. All these complications recovered with institution of corticosteroids.

How to cite this article

Sharma A, Kumar S, Goyal P, Law AD, Lal A, Singh S. Steroid Responsive Parenchymal Lung Involvement and Acute Renal Failure in a Patient with Relapsing Polychondritis. J Postgrad Med Edu Res 2012;46(4):198-201.
Assessment of the abuse of tapentadol immediate release: The first 24 months
Authors: Dart, MD, PhD Richard C. , Cicero, PhD Theodore J. , Surratt, PhD Hilary L. , Rosenblum, PhD Andrew , Bartelson, PhD Becki Bucher , Adams, ScD Edgar H.
Published: January 2013

Objective: Prescription opioid analgesics play an important role in the management of moderate to severe pain. An unintended consequence of prescribing opioid analgesics is the abuse and diversion of these medications. The authors estimated abuse and diversion rates for tapentadol immediate release (IR) compared with oxycodone, hydrocodone, and tramadol during the first 24 months of tapentadol IR availability.Methods: The Researched Abuse, Diversion and Addiction-Related Surveillance (RADARS®) System measures rates of prescription opioid abuse and diversion throughout the United States. Quarterly data from the Poison Center, Drug Diversion, Opioid Treatment, and Survey of Key Informants’ Patients (SKIP) programs were plotted to visually compare the rates of tapentadol IR abuse and diversion with those of other opioid analgesics from July 2009 through June 2011 using both cases per 100,000 population and per 1,000 unique recipients of dispensed drug (URDD) as denominators. Trends in abuse and diversion rates over time were determined using a linear regression model of rate versus time.Results: During the 24 months following its introduction, tapentadol IR had very low population-based rates of abuse and diversion that were similar to rates for tramadol and lower than rates for oxycodone and hydrocodone. Rates of tapentadol IR abuse and diversion based on URDD were variable by program due to changes in market share and had not stabilized as of June 2011.Conclusions: Rates of tapentadol IR abuse and diversion have been low during the first 24 months after its launch. Continued monitoring of trends in these data is warranted.
The Arctic response to remote and local forcing of black carbon
Authors: Sand M. , Berntsen T. K. , Kay J. E. , Lamarque J. F. , Seland Ø. , Kirkevåg A.
Published: January 2013

Abstract. Recent studies suggest that the Arctic temperature response to black carbon (BC) forcing depend strongly on the location of the forcing. We investigate how atmospheric BC in the mid-latitudes remotely influence the Arctic climate, and compare this with the response to atmospheric BC located in the Arctic itself. In this study, idealized climate simulations are carried out with a fully coupled Earth System Model, which includes a comprehensive treatment of aerosol microphysics. In order to determine how BC transported to the Arctic and BC sources not reaching the Arctic impact the Arctic climate, atmospheric BC concentrations are scaled up in the mid-latitudes (28–60° N) and in the Arctic (60–90° N), respectively. Estimates of the impact on the Arctic energy budget are represented by analyzing radiation fluxes at the top of the atmosphere and at the surface, surface turbulent fluxes, and meridional heat transport in the atmosphere. Our calculations show that increased BC forcing in the Arctic atmosphere reduces the surface air temperature in the Arctic with a corresponding increase in the sea-ice fraction, despite the increased planetary absorption of sunlight. The analysis indicates that this effect is due to a combination of a weakening of the northward heat transport caused by a reduction in the meridional temperature gradient and a dimming at the surface. On the other hand we find that BC forcing at the mid-latitudes warms the Arctic surface significantly and decreases the sea-ice fraction. Our model calculations indicate that atmospheric BC forcing outside the Arctic may be more important for the Arctic climate change than the forcing in the Arctic itself. These results suggest that mitigation strategies for the Arctic climate should also address BC sources in locations outside the Arctic even if they do not contribute much to BC in the Arctic.
Measuring and modeling the hygroscopic growth of two humic substances in mixed aerosol particles of atmospheric relevance
Authors: Zamora I. R. , Jacobson M. Z.
Published: January 2013

Abstract. The hygroscopic growth of atmospheric particles affects atmospheric chemistry and Earth's climate. Water-soluble organic carbon (WSOC) constitutes a significant fraction of the dry submicron mass of atmospheric aerosols, thus affecting their water uptake properties. Although the WSOC fraction is comprised of many compounds, a set of model substances can be used to describe its behavior. For this study, mixtures of Nordic Aquatic fulvic acid reference (NAFA) and Fluka humic acid (HA), with various combinations of inorganic salts (sodium chloride and ammonium sulfate) and other representative organic compounds (levoglucosan and succinic acid), were studied. We measured the equilibrium water vapor pressure over bulk solutions of these mixtures as a function of temperature and solute concentration. New water activity (aw) parameterizations and hygroscopic growth curves at 25 °C were calculated from these data for particles of equivalent composition. We examined the effect of temperature on the water activity and found a maximum variation of 9% in the 0–30 °C range, and 2% in the 20–30 °C range. Five two-component mixtures were studied to understand the effect of adding a humic substance (HS), such as NAFA and HA, to an inorganic salt or a saccharide. The deliquescence point at 25 °C for HS-inorganic mixtures did not change significantly from that of the pure inorganic species. However, the hygroscopic growth of HA-inorganic mixtures was lower than that exhibited by the pure salt, in proportion to the added mass of HA. The addition of NAFA to a highly soluble solute (ammonium sulfate, sodium chloride or levoglucosan) in water had the same effect as the addition of HA to the inorganic species for most of the aw range studied. Yet, the water uptake of these NAFA mixtures transitioned to match the growth of the pure salt or saccharide at high aw values. The remaining four mixtures were based on chemical composition data for different aerosol types. As expected, the two solutions representing organic aerosols (40% HS/40% succinic acid/20% levoglucosan) showed lower water uptake than the two solutions representing biomass burning aerosols (25% HS/27% succinic acid/18% levoglucosan/30% ammonium sulfate). However, interactions in multicomponent solutions may be responsible for the differences that arise in relative hygroscopic growth above RH of 95% when comparing three different HS in these two mixtures. The ZSR model was able to predict reasonably well the hygroscopic growth of all the mixtures below aw = 0.95, but produced large deviations for some multicomponent mixtures at higher values.
A plume-in-grid approach to characterize air quality impacts of aircraft emissions at the Hartsfield-Jackson Atlanta International Airport
Authors: Rissman J. , Arunachalam S. , Woody M. , West J. J. , BenDor T. , Binkowski F. S.
Published: January 2013

Abstract. This study examined the impacts of aircraft emissions during the landing and takeoff cycle on PM2.5 concentrations during the months of June 2002 and July 2002 at the Hartsfield-Jackson Atlanta International Airport. Primary and secondary pollutants were modeled using the Advanced Modeling System for Transport, Emissions, Reactions, and Deposition of Atmospheric Matter (AMSTERDAM). AMSTERDAM is a modified version of the Community Multiscale Air Quality (CMAQ) model that incorporates a plume-in-grid process to simulate emissions sources of interest at a finer scale than can be achieved using CMAQ's model grid. Three fundamental issues were investigated: the effects of aircraft on PM2.5 concentrations throughout northern Georgia, the differences resulting from use of AMSTERDAM's plume-in-grid process rather than a traditional CMAQ simulation, and the concentrations observed in aircraft plumes at sub-grid scales. Comparison of model results with an air quality monitor located in the vicinity of the airport found that normalized mean bias ranges from −77.5% to 6.2% and normalized mean error ranges from 40.4% to 77.5%, varying by species. Aircraft influence average PM2.5 concentrations by up to 0.232 μg m−3 near the airport and by 0.001–0.007 μg m−3 throughout the Atlanta metro area. The plume-in-grid process increases concentrations of secondary PM pollutants by 0.005–0.020 μg m−3 (compared to the traditional grid-based treatment) but reduces the concentration of non-reactive primary PM pollutants by up to 0.010 μg m−3, with changes concentrated near the airport. Examination of sub-grid scale results indicates that puffs within 20 km of the airport often have average PM2.5 concentrations one order of magnitude higher than aircraft contribution to the grid cells containing those puffs, and within 1–4 km of emitters, puffs may have PM2.5 concentrations 3 orders of magnitude greater than the aircraft contribution to their grid cells. 21% of all aircraft-related puffs from the Atlanta airport have at least 0.1 μg m−3 PM2.5 concentrations. Median daily puff concentrations vary between 0.017 and 0.134 μg m−3, while maximum daily puff concentrations vary between 6.1 and 42.1 μg m−3 during the 2-month period. In contrast, median daily grid concentrations vary between 0.015 and 0.091 μg m−3, while maximum daily grid concentrations vary between 0.751 and 2.55 μg m−3. Future researchers may consider using AMSTERDAM to understand the impacts of aircraft emissions at other airports, for proposed future airports, for airport expansion projects under various future scenarios, and for other national-scale studies specifically when the maximum impacts at fine scales are of interest.
Water vapour and the equatorial mesospheric semi-annual oscillation (MSAO)
Authors: Gattinger R. L. , Kyrölä E. , Boone C. D. , Evans W. F. J. , Walker K. A. , McDade I. C. , Bernath P. F. , Llewellyn E. J.
Published: January 2013

Abstract. Observations of the mesospheric semi-annual oscillation (MSAO) in the equatorial region have been reported dating back several decades. Seasonal variations in both species densities and airglow emissions are well documented. The extensive observations available offer an excellent case study for comparison with model simulations. The broad range of measurements is summarised with emphasis on the 80 to 100 km region. Photochemical model simulations are described for near-equinox and near-solstice conditions, the two times with notable differences in the observed MSAO parameters. Diurnal tides are included in order to facilitate comparisons of observations made at different local times. The roles of water vapour as the "driver" species and ozone as the "response" species are examined to test for consistency between the model results and observations. The model simulations suggest the interactions between eddy mixing and background vertical advection play a significant role in the MSAO phenomenon. At the equator, 90 km altitude, the derived eddy mixing rate is approximately 1 × 106 cm2 s−1 and vertical advection 0.8 cm s−1. For April the corresponding values are 4 × 105 cm2 s−1 and 0.1 cm s−1.
Sources, trends and regional impacts of fine particulate matter in southern Mississippi Valley: significance of emissions from sources in the Gulf of Mexico coast
Authors: Chalbot M.-C. , McElroy B. , Kavouras I. G.
Published: January 2013

Abstract. The sources of fine particles over a 10 yr period at Little Rock, Arkansas, an urban area in southern Mississippi Valley, were identified by positive matrix factorization. The annual trends of PM2.5 and its sources and their associations with the pathways of air mass backward trajectories were examined. Seven sources were apportioned, namely, primary traffic particles, secondary nitrate and sulphate, biomass burning, diesel particles, aged/contaminated sea salt and mineral/road dust, accounting for more than 90% of measured PM2.5 mass. The declining trend of PM2.5 mass (0.4 μg m−3 yr−1) was related to lower levels of SO42− (0.2 μg m−3 yr−1) due to SO2 reductions from point and mobile sources. The slower decline for NO3− particles (0.1 μg m−3 yr−1) was attributed to the spatial variability of NH3 in Midwest. The annual variation of biomass burning particles was associated with wildland fires in southeast and northwest US that are sensitive to climate changes. The four regions within 500 km from the receptor site, the Gulf Coast and southeast US accounted cumulatively for more than 65% of PM2.5 mass, nitrate, sulphate and biomass burning aerosol. Overall, more than 50% of PM2.5 and its sources originated from sources outside the state. Sources within the Gulf Coast and western Gulf of Mexico include 65% of the busiest ports in the US, intense marine traffic within 400 km of the coast burning rich in S diesel, and a large number of offshore oil and natural gas platforms and many refineries along the coast. This approach allowed for quantitatively assessing the impacts of transport from regions representing diverse mixtures of sources and weather conditions for different types of particles. The findings of this effort demonstrated the influences of emission controls on SO2 and NOx on PM2.5 mass, the potential effect of events (i.e. fires) sensitive to climate change phenomena on air pollution and the potential of offshore activities and shipping emissions to influence air quality in urban areas located more than 1000 km away from the sources.
Analysis of a winter regional haze event and its formation mechanism in the North China Plain
Authors: Zhao X. J. , Zhao P. S. , Xu J. , Meng W. , Pu W. W. , Dong F. , He D. , Shi Q. F.
Published: January 2013

Abstract. A regional haze episode occurred in the Beijing, Tianjin and Hebei province (BTH) area in the North China Plain (NCP) from 16 to 19 January 2010. The chemical and optical properties of aerosols and the meteorological condition were investigated in this study with intensive measurement of aerosol and trace gases from 14 to 23 January 2010 at five sites. The episode was caused by the combination of anthropogenic emissions and surface air stagnation under a high pressure system followed by a low pressure system. The concentrations of PM2.5 and trace gases increased significantly on a regional scale during this episode. The increased aerosol scattering coefficient (σsp), absorption coefficient (σap), and aerosol optical depth (AOD) showed the importance of aerosol extinction during this haze episode. The increase of secondary inorganic pollutants (SO42−, NO3−, NH4+) was observed simultaneously at four sites, especially in the plain area of BTH, which could be identified as a common characteristic of pollution haze in east China. The organic matter (OM) was different from secondary inorganic pollutants, which increased more significantly at Chengde (CD) site than the other three sites in plain area. The sulfate and nitrate in PM2.5 were mainly formed through the heterogeneous reaction process in the urban area. The secondary organic aerosols in PM2.5 only existed during haze days at CD but in both haze and normal days at the other three sites. The chemical characteristics of aerosols in PM2.5 indicated that the secondary formation of aerosol was one important mechanism in the formation of haze episode. The strong temperature inversion and descending air motions in the planetary boundary layer (PBL) allowed pollutants to accumulate in a shallow layer. The weak surface wind speed produced high pollutants concentration within these source regions. The accumulation of pollutants was one main factor in the haze formation. The enhanced southwest wind in the last period of this episode transported pollutants to the downwind area and expanded the regional scope of the haze.
Volcanic SO2 and SiF4 visualization using 2-D thermal emission spectroscopy – Part 2: Wind propagation and emission rates
Authors: Krueger A. , Stremme W. , Harig R. , Grutter M.
Published: January 2013

Abstract. A technique for measuring two-dimensional (2-D) plumes of volcanic gases with thermal emission spectroscopy was described in Part 1 by Stremme et al. (2012a). In that paper the instrumental aspects as well as retrieval strategies for obtaining the slant column images of SO2 and SiF4, as well as animations of particular events observed at the Popocatépetl volcano, were presented. This work focuses on the procedures for determining the propagation speed of the gases and estimating an emission rate from the given image sequences. A 2-D column density distribution of a volcanic gas, available as time-consecutive frames, provides information of a projected wind field and the average velocity at which the volcanic plume is propagating. This information is valuable since the largest uncertainties when calculating emission rates of the gases using remote sensing techniques arise from propagation velocities which are often inadequately assumed. The presented reconstruction method solves the equation of continuity as an ill-posed problem using mainly a Tikhonov-like regularisation. It is observed from the available data sets that if the main direction of propagation is perpendicular to the line-of-sight, the algorithm works well for SO2, which has the strongest signals, and also for SiF4 in some favourable cases. Due to the similarity of the algorithm used here with the reconstruction methods used for profile retrievals based on optimal estimation theory, diagnostic tools like the averaging kernels can be calculated in an analogous manner and the information can be quantified as degrees of freedom. Thus, it is shown that the combination of wind field and column distribution of the gas plume can provide the emission rate of the volcano both during day and night.
One year of continuous measurements constraining methane emissions from the Baltic Sea to the atmosphere using a ship of opportunity
Authors: Gülzow W. , Rehder G. , Schneider v. Deimling J. , Seifert T. , Tóth Z.
Published: January 2013

Abstract. Methane and carbon dioxide were measured with an autonomous and continuous running system on a ferry line crossing the Baltic Sea on a 2–3 day interval from the Mecklenburg Bight to the Gulf of Finland in 2010. Surface methane saturations show great seasonal differences in shallow regions like the Mecklenburg Bight (103–507%) compared to deeper regions like the Gotland Basin (96–161%). The influence of controlling parameters like temperature, wind, mixing depth and processes like upwelling, mixing of the water column and sedimentary methane emissions on methane oversaturation and emission to the atmosphere are investigated. Upwelling was found to influence methane surface concentrations in the area of Gotland significantly during the summer period. In February 2010, an event of elevated methane concentrations in the surface water and water column of the Arkona Basin was observed, which could be linked to a wind-derived water level change as a potential triggering mechanism. The Baltic Sea is a source of methane to the atmosphere throughout the year, with highest fluxes occurring during the winter season. Stratification was found to promote the formation of a methane reservoir in deeper regions like Gulf of Finland or Bornholm Basin, which leads to long lasting elevated methane concentrations and enhanced methane fluxes, when mixed to the surface during mixed layer deepening in autumn and winter. Methane concentrations and fluxes from shallow regions like the Mecklenburg Bight are predominantly controlled by sedimentary production and consumption of methane, wind events and the change in temperature-dependent solubility of methane in the surface water. Methane fluxes vary significantly in shallow regions (e.g. Mecklenburg Bight) and regions with a temporal stratification (e.g. Bornholm Basin, Gulf of Finland). On the contrary, areas with a permanent stratification like the Gotland Basin show only small seasonal fluctuations in methane fluxes.
Temperature effects on carbon-specific respiration rate and sinking velocity of diatom aggregates – potential implications for deep ocean export processes
Authors: Iversen M. H. , Ploug H.
Published: January 2013

Abstract. Most deep ocean carbon flux profiles show low and almost constant fluxes of particulate organic carbon (POC) in the deep ocean. However, the reason for the seemingly non-changing POC fluxes at depths is unknown. This study presents direct measurements of formation, degradation, and sinking velocity of diatom aggregates from laboratory studies performed at 15 °C and 4 °C during a three week experiment. The average carbon-specific respiration rate during the experiment was 0.12 ± 0.03 at 15 °C, and decreased 3.5-fold when the temperature was lowered to 4 °C. No direct influence of temperature on aggregate sinking speed was observed. Using the remineralisation rate measured at 4 °C and an average particle sinking speed of 150 m d−1, calculated carbon fluxes were similar to those collected in deep ocean sediment traps from a global data set, indicating that temperature plays a major role for deep ocean fluxes of POC.