bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of an Outbreak of Hemorrhagic Fever with Renal Syndrome in College Students in Xi’an, China
Authors: Ma Chaofeng , Wang Zengguo , Li Shen , Xing Yuan , Wu Rui , Wei Jing , Nawaz Muhammad , Tian Huaiyu , Xu Bing , Wang Jingjun , Yu Pengbo
Published: January 2014

The aim of the present study was to analyze an outbreak of hemorrhagic fever with renal syndrome (HFRS), caused by a Hantavirus, in college students in the northern urban area of Xi’an in 2012. The outbreak affected six students and included two deaths. The epidemiological survey revealed that both of the deceased cases were misdiagnosed initially, and treatment was delayed. Furthermore, a higher rodent population density and lower HFRS vaccine coverage were observed in the affected area, which indicates a possible role in the outbreak. Rattus norvegicus (Rn) and Mus musculus (Mm) were the predominant host populations in the area. Genotyping revealed that all HVs from patients and rodents were Hantaan virus (HTNV). Sequence analysis of the S segments revealed that the HTNVs reported in this study had high similarity with strains reported in 2011 and 1985, but these viruses diverged from a strain isolated in 1984 and the HTNV prototype strain 76-118. Detection of anti-HV IgG and amplification of the S segment of HTNV from a non-natural HTNV reservoir indicates that further investigations by increased rodent trapping are necessary.
Espace du marché et mode de domination
Authors: Garcia Marie-France
Published: January 2014

The Marketplace and Form of Domination -

The ethnographical analysis of the Serro-Azul marketplace, located in the middle of a big sugar plantation in the Nordeste, Brazil, casts doubt on the widely accepted idea that market relationships rime with freedom and open doors toward the world. Following a description of its historical, social and institutional context, the market is shown to be a way of restoring the senhors traditional domination over the morador. The concentration of land-holdings and the appearance of new actors in the local context threatens this form of domination.
Le temps de la politique
Authors: Palmeira Moacir , Heredia Beatriz
Published: January 2014

Cet article analyse le rôle des meetings politiques lors des campagnes électorales dans l'adhésion des habitants des communes rurales aux diverses factions qui les divisent. Parmi toutes les formes de manifestations publiques qui foisonnent pendant ces périodes de campagnes, il privilégie les meetings comme dramatisation de la rencontre entre le haut et le bas de la hiérarchie sociale et des factions politiques rivales. Ces rituels politiques s'avèrent essentiels dans la construction sociale d'un moment particulier, le temps de la politique, qui permet à la société de se constituer en réseaux de sociabilité autres que la famille, le voisinage, la communauté religieuse.
Convergent synthesis of a tetrasaccharide repeating unit of the O-specific polysaccharide from the cell wall lipopolysaccharide of Azospirillum brasilense strain Sp7
Authors: Mandal Pintu Kumar , Dhara Debashis , Misra Anup Kumar
Published: January 2014

A straightforward convergent synthesis has been carried out for the tetrasaccharide repeating unit of the O-specific cell wall lipopolysaccharide of the strain Sp7 of Azospirillum brasilense. The target tetrasaccharide has been synthesized from suitably protected monosaccharide intermediates in 42% overall yield in seven steps by using a [2 + 2] block glycosylation approach.
Morphological and Geographical Traits of the British Odonata
Authors: Powney Gary , Brooks Stephen , Barwell Louise , Bowles Phil , Fitt Robert , Pavitt Alyson , Spriggs Rebecca , Isaac Nick
Published: January 2014

Trait data are fundamental for many aspects of ecological research, particularly for modeling species response to environmental change. We synthesised information from the literature (mainly field guides) and direct measurements from museum specimens, providing a comprehensive dataset of 26 attributes, covering the 43 resident species of Odonata in Britain. Traits included in this database range from morphological traits (e.g. body length) to attributes based on the distribution of the species (e.g. climatic restriction). We measured 11 morphometric traits from five adult males and five adult females per species. Using digital callipers, these measurements were taken from dry museum specimens, all of which were wild caught individuals. Repeated measures were also taken to estimate measurement error. The trait data are stored in an online repository (https://github.com/BiologicalRecordsCentre/Odonata_traits), alongside R code designed to give an overview of the morphometric data, and to combine the morphometric data to the single value per trait per species data.
Quelques éléments de compréhension psycho-dynamique sur les dispositifs Maison de l'adolescent (MDA)
Authors: Labrune Laurent
Published: January 2014

L’objet de cet article est de proposer quelques éléments de compréhension psycho-dynamique concernant les dispositifs Maison de l’adolescent (MDA). Ces dispositifs sont issus de projets récents, à la dynamique nouvelle, et « en construction » selon des modèles et des organisations multiples. Sont abordés la dynamique induite par un tel projet en évolution et en transformation (la construction de soi et la problématique de l’idéalisation concernée), la similarité induite entre dispositif en développement et processus d’adolescence, celles de l’organisation et de la pulsionnalité, les investissements objectaux et le multiple, la dimension identitaire, enfin le rôle du regard porté sur les dispositifs en création.
Building Collaborative Virtual Communities in a University Department of Early Childhood Education for Wikipedia Article Authoring
Authors: Prentzas Jim , Rekalidou Galini
Published: January 2014

Collaborative and student-centered learning are endorsed by modern educational approaches and (to a certain degree) are applied to educational environments. Early childhood education puts emphasis on such issues. Wiki environments provide the infrastructure for supporting collaborative learning and student-centered learning tasks. Consequently, wiki activities are gradually becoming part of teacher education curriculum. This chapter discusses issues regarding the incorporation of wikis in teacher education curriculum. The most recent corresponding approaches are categorized according to different views, and the most important findings are discussed. An approach aiming to create collaborative virtual communities for Wikipedia article authoring is also presented. The approach has been applied to a university department of early childhood education. To support communication among participants, face-to-face, e-mail communication, and tools encompassed in an open source Learning Management System were employed. Preliminary results are presented showing a positive response of the pre-service early childhood teachers. Lastly, conclusions and future research directions are outlined.
Making Sense of Building Online Learning Communities
Authors: Kwapy Justina
Published: January 2014

The last decade has brought an increase in online courses in the educational setting. Online enrollment has increased from 1.98 million in 2003 to 2.35 million in 2004 (Allen & Seaman, 2005). While students, higher universities, and faculty are enjoying the convenience and flexibility of online learning environments, there is an increasing concern over the support in distance education, teaching methods, and a social disconnectedness of students from the course. This chapter explores how these factors can impede a successful online learning experience and can cause dissatisfaction and higher dropout rates among students in distance learning programs. Carr (2000) found higher dropout rates for distance education (10-20%) over traditional programs. Higher institution’s online faculty are now faced with the task of creating a virtual community of learners, meeting both academic and social needs of students.
From “Sage on the Stage” to Facilitator of Learning
Authors: Passmore Denise
Published: January 2014

This chapter explores through phenomenological methodology the experiences of nursing faculty who transitioned from live to online teaching. These experiences are further examined through the theory of transformative learning to determine whether participants were able to transform their teaching identity from traditional classroom teacher (sage on the stage) to facilitators of learning. One-on-one interviews were conducted with 16 full-time nursing faculty at 4 state universities. Findings revealed that most faculty were originally hesitant to teach online and had multiple misconceptions regarding teaching methods and online student communication. With one exception, professional development for online teaching was limited. Most participants described transforming their teaching methods and philosophies as they gained more experience. Results implicate that faculty development should focus not only on educational principles and technology but also ways to connect with students and develop course content that helps maintain faculty identities.
Online Learning
Authors: Baran Mette L. , Jones Janice E.
Published: January 2014

This chapter answers the following question posed by the book editors: “What are some guidelines for working effectively in virtual teams?” To further advance existing literature, the authors utilize a qualitative phenomenological approach with a randomly sampled group of seven students who have completed Master’s level Education courses that were conducted in an online format at a private Midwestern university. Students were half way through their course completion at the time of data collection. In addition, a random sample of one program administrator and four faculty members are interviewed. Specifically, students who enrolled in online Master’s in Education courses are required to work in study teams to complete a certain portion of the course work. Study teams can often be difficult to navigate in person and with the added dimension that a virtual experience brings to developing trusting, successful working relationships, different working guidelines are needed. Findings reveal that managerial and social aspects of online learning and teaching are critical for online students’ success.
A Distributed Community of Practice to Facilitate Communication, Collaboration, and Learning among Faculty
Authors: Coto Mayela
Published: January 2014

Recent research suggests that professional development initiatives within the framework of a community of practice are more likely to have an effective result than traditional forms of professional development. The overall objective of this chapter is to present a study that aims to improve the understanding of how a distributed community of practice approach affects communication, collaboration, and professional development of faculty, and whether this leads to promote a transformation in teaching practices. The results indicate that a community approach to professional development in higher education is feasible but requires careful design if it is to work with a wide range of faculty staff. Findings also show that while the approach has been successful in many areas, there are aspects that require further work and research.
Angiosarcoma of the Seminal Vesicle: A Case Report of Long-Term Survival following Multimodality Therapy
Authors: Chang Kenneth , Sio Terence T. , Chandan Vishal S. , Iott Matthew J. , Hallemeier Christopher L.
Published: January 2014

Angiosarcoma of the seminal vesicle is an extremely rare malignancy, with few published case reports in the literature. We present a case of primary angiosarcoma of the seminal vesicle in a 45-year-old male who was treated with multimodality therapy, consisting of neoadjuvant chemotherapy and chemoradiation followed by surgical resection and intraoperative radiation therapy. He has been free of cancer recurrence for more than six years after completion of therapy. To our knowledge, this represents the longest reported survival of a patient with this rare tumor, and one of the few cases reported using a multimodality therapy approach.
Qualitative and quantitative assessment of relationship between mandibular third molar and angle fracture on North Indian population: A clinico-radiographic study
Authors: Yadav Suresh , Tyagi Shallu , Puri Naveen , Kumar Prince , Kumar Puneet
Published: January 2014

Objective: To assess the relationship between impacted mandibular third molar presence and the risk for mandibular angle fracture with the effect of various positions of mandibular third molar and the risk of mandibular angle fracture. Materials and Methods: In the North Indian territory, a total of 289 patients with mandibular angle fractures were studied and evaluated for the possible relationship with impacted third molar on the basis of clinical and panoramic radiographical findings. Results: Results that confirmed the highest risk for mandibular angle fracture was associated with mesioangular angulations (45.42%) followed by vertical (26.34%), distoangular in sequence and least risk was found with bucco-version angulations (2.67%) according to Winter′s classification. Additionally, the highest risk of mandibular angle fracture was reported with partially erupted third molar (47.75%), followed by erupted (23.53%) and unerupted third molar (19.38%). Conclusion: The risk for mandibular angle fracture is not only affected by status of eruption, angulations, position, number of roots present in third molar but also by the distance of mandibular third molar from inferior border of mandible and the percentage of remaining amount of bone at the mandibular angle region.
Pulmonary Heart Disease: The Heart‐Lung Interaction and its Impact on Patient Phenotypes
Authors: Forfia Paul R. , Vaidya Anjali , Wiegers Susan E.
Published: January 2014

Pulmonary heart disease (PHD) refers to altered structure or function of the right ventricle occurring in association with abnormal respiratory function. Although nearly always associated with some degree of PH, the degree, nature, severity, and causality of PH in relation to the PHD is not necessarily linear and direct. Abnormal gas exchange is a fundamental underpinning of PHD, affecting pulmonary vascular, cardiac, renal, and neurohormonal systems. Direct and indirect effects of chronic respiratory disease can disrupt the right ventricular‐pulmonary arterial (RV‐PA) interaction and, likewise, factors such as sympathetic nervous system activation, altered blood viscosity, and salt and water retention can function in a feedback loop to further influence RV‐PA function. Left heart function may also be affected, especially in those with pre‐existing left heart disease. Thus, the physiologic interactions between abnormal respiratory and cardiovascular function are complex, with PHD representing a heterogeneous end organ effect of an integrated multisystem process. In this review, we propose to separate PHD into two distinct entities, “Type I” and “Type II” PHD. Type I PHD is most common, and refers to subjects with chronic respiratory disease (CRD) where the perturbations in respiratory function dominate over more mild cardiac and circulatory disruptions. In contrast, Type II PHD refers to the smaller subset of patients with more severe pulmonary vascular and right heart dysfunction, whom often present in a fashion similar to patients with PAH. Phenotypic differences are not made by PA pressure alone, but instead by differences in the overall physiology and clinical syndrome. Thus, key differences can be seen in symptomatology, physical signs, cardiac imaging, hemodynamics, and the cardiovascular and gas exchange responses to exercise. Such key baseline differences in the overall physiologic phenotype are likely critical to predicting response to PH specific therapy. Recognizing PHD as distinct phenotypes assists in the necessary distinction of these patients, and may also provide a key clinical and pathophysiologic framework for improved patient selection for future studies investigating the role of pulmonary hypertension‐specific therapies in PHD.
Vascular Histomolecular Analysis by Sequential Endoarterial Biopsy in a Shunt Model of Pulmonary Hypertension
Authors: Rothman Abraham , Davidson Stephanie , Wiencek Robert G. , Evans William N. , Restrepo Humberto , Sarukhanov Valeri , Ruoslahti Erkki , Williams Roy , Mann David
Published: January 2014

The molecular mechanisms of pulmonary arterial hypertension (PAH) remain ill‐defined. The aims of this study were to obtain sequential endoarterial biopsy samples in a surgical porcine model of PAH and assess changes in histology and mRNA expression during the disease progression. Differentially expressed genes were then analyzed as potential pharmacological targets. Four Yucatan micro‐pigs underwent surgical anastomosis of the left pulmonary artery to the descending aorta. Endovascular samples were obtained with a biopsy catheter at baseline (before surgery) and from the left lung 7, 60, and 180 days after surgery. RNA was isolated from biopsy samples, amplified and analyzed. Dysregulated genes were linked to drugs with potential to treat or prevent PAH. With the development of PAH in our model, we identified changes in histology and in the expression of several genes with known or investigational inhibitors and several novel genes for PAH. Gene dysregulation displayed time‐related variations during disease progression. Endoarterial biopsy provides a new method of assessing pulmonary vascular histology and gene expression in PAH. This analysis could identify novel applications for existing and new PAH drugs. The detection of stage‐ and disease‐specific variation in gene expression could lead to individualized therapies.
Comparison of Acute Hemodynamic Effects of Inhaled Nitric Oxide and Inhaled Epoprostenol in Patients with Pulmonary Hypertension
Authors: Preston Ioana R. , Sagliani Kristen D. , Roberts Kari E. , Shah Archan M. , DeSouza Shilpa A. , Howard William , Brennan John , Hill Nicholas S.
Published: January 2014

Inhaled nitric oxide (iNO) is used for acute vasoreactivity testing in pulmonary arterial hypertension (PAH) patients. Inhaled epoprostenol (iPGI2) has pulmonary selectivity and is less costly. We sought to compare acute hemodynamic effects of iNO (20 ppm) and iPGI2 (50 ng/kg/min) and determine whether their combination has additive effects. We conducted a prospective, single center, randomized, cross‐over study in 12 patients with PAH and seven with heart failure with preserved ejection fraction (HFpEF). In PAH patients, iNO lowered mean pulmonary artery pressure (mPAP) by 9 ± 12% and pulmonary vascular resistance (PVR) by 14 ± 32% (mean ± SD). iPGI2 decreased mPAP by 10 ± 12% and PVR by 12 ± 36%. Responses to iNO and iPGI2 in mPAP and PVR were directly correlated (r2 = 0.68, 0.70, respectively, P > 0.001). In HFpEF patients, mPAP dropped by 4 ± 7% with each agent, and PVR dropped by 33 ± 23% with iNO, and by 25 ± 29% with iPGI2 (P = NS). Pulmonary artery wedge pressure (PAWP) increased significantly with iPGI2 versus baseline (20 ± 3 vs. 17 ± 2 mmHg, P = 0.02) and trended toward an increase with iNO and the combination (20 ± 2, 19± 4 mmHg, respectively). There were no additive effects in either group. In PAH patients, the vasodilator effects of iNO and iPGI2 correlated at the doses used, making iPGI2 a possible alternative for testing acute vasoreactivity, but their combination lacks additive effect. Exposure of HFpEF patients to inhaled vasodilators worsens the PAWP without hemodynamic benefit.
Updating Clinical Endpoint Definitions
Authors: Hassoun Paul M. , Nikkho Sylvia , Rosenzweig Erika B. , Moreschi Gail , Lawrence John , Teeter John , Meier Christian , Ghofrani Ardeshir H. , Minai Omar , Rinaldi Paula , Michelakis Evangelos , Oudiz Ronald J
Published: January 2014

The 6‐Minute Walk Distance (6‐MWD) has been the most utilized endpoint for judging the efficacy of pulmonary arterial hypertension (PAH) therapy in clinical trials conducted over the past two decades. Despite its simplicity, widespread use in recent trials and overall prognostic value, the 6‐MWD has often been criticized over the past several years and pleas from several PAH experts have emerged from the literature to find alternative endpoints that would be more reliable in reflecting the pulmonary vascular resistance as well as cardiac status in PAH and their response to therapy. A meeting of PAH experts and representatives from regulatory agencies and pharmaceutical companies was convened in early 2012 to discuss the validity of current as well as emerging valuable endpoints. The current work represents the proceedings of the conference.
Phospholipase D Signaling Mediates Reactive Oxygen Species‐Induced Lung Endothelial Barrier Dysfunction
Authors: Usatyuk Peter V. , Kotha Sainath R. , Parinandi Narasimham L. , Natarajan Viswanathan
Published: January 2014

Reactive oxygen species (ROS) have emerged as critical players in the pathophysiology of pulmonary disorders and diseases. Earlier, we have demonstrated that ROS stimulate lung endothelial cell (EC) phospholipase D (PLD) that generates phosphatidic acid (PA), a second messenger involved in signal transduction. In the current study, we investigated the role of PLD signaling in the ROS‐induced lung vascular EC barrier dysfunction. Our results demonstrated that hydrogen peroxide (H2O2), a typical physiological ROS, induced PLD activation and altered the barrier function in bovine pulmonary artery ECs (BPAECs). 1‐Butanol, the quencher of PLD, generated PA leading to the formation of physiologically inactive phosphatidyl butanol but not its biologically inactive analog, 2‐butanol, blocked the H2O2‐mediated barrier dysfunction. Furthermore, cell permeable C2 ceramide, an inhibitor of PLD but not the C2 dihydroceramide, attenuated the H2O2‐induced PLD activation and enhancement of paracellular permeability of Evans blue conjugated albumin across the BPAEC monolayers. In addition, transfection of BPAECs with adenoviral constructs of hPLD1 and mPLD2 mutants attenuated the H2O2‐induced barrier dysfunction, cytoskeletal reorganization and distribution of focal adhesion proteins. For the first time, this study demonstrated that the PLD‐generated intracellular bioactive lipid signal mediator, PA, played a critical role in the ROS‐induced barrier dysfunction in lung vascular ECs. This study also underscores the importance of PLD signaling in vascular leak and associated tissue injury in the etiology of lung diseases among critically ill patients encountering oxygen toxicity and excess ROS production during ventilator‐assisted breathing.
Integrating Molecular Genetics and Systems Approaches to Pulmonary Vascular Diseases
Authors: Geraci Mark W.
Published: January 2014

There is incredible potential to advance our understanding of disease pathogenesis, enhance our diagnostic capability, and revolutionize our treatment modalities with the advent of advanced systems approaches to genetic, genomic, and epigenetic discoveries. Investigation using these technologies is beginning to impact our understanding of pulmonary arterial hypertension (PAH). The following review details work to date on single gene mutations in PAH, and expression array analysis in the disease. The wider use of DNA‐based arrays for genome wide association studies (GWAS) and copy number alterations is examined. The impact of epigenomic modulation in the pathobiology of PAH and its therapeutic implications is investigated. Finally, a summary of the capabilities and promises for next‐generation sequencing is discussed. A framework for studies of the future is proposed.
Nonfunctional Islet Cell Tumor of the Pancreas in a Patient with Tuberous Sclerosis: A Case Report with Literature Review
Authors: Cansu Aysegul , Ahmetoglu Ali , Kul Sibel , Uzman Dilek , Ersoz Safak
Published: January 2014

Islet cell tumors (ICTs) are rare tumors of the pancreas. Association of this type of tumor with tuberous sclerosis is extremely rare. Only 13 cases of pancreatic ICT with tuberous sclerosis have so far been documented in the literature. However, awareness of the association of tuberous sclerosis and ICT is important for early diagnosis and appropriate treatment of this condition. This article presents the case of a 63-year-old female with angiomyolipoma (AML) of the kidney and liver, calcified subependymal nodules and a large mass in the pancreas, which was proven to be an ICT on histopathological examination.
Two Cases of Spinal, Extraosseous, Intradural Ewing's sarcoma/Peripheral Neuroectodermal Tumor: Radiologic, Pathologic, and Molecular Analysis
Authors: Mardekian Stacey K , Gandhe Ashish , Miettinen Markku , Pack Svetlana , Curtis Mark T , Abdullaev Ziedulla
Published: January 2014

Extraosseous Ewing's sarcoma/peripheral neuroectodermal tumors (ES/PNETs) are rare neoplasms that account for approximately 10%-15% of soft tissue sarcomas in children and 5% of soft tissue sarcomas in adults. Primary spinal, extraosseous, intradural ES/PNETs are even less common. The diagnosis of ES/PNET is extremely challenging, because the tumor can have a nonspecific radiologic appearance, and the histologic features are shared by many other “small round cell tumors.” Thus, ES/PNET should be included in the radiologic and pathologic differential diagnosis, even in older patients and in unusual tumor sites. We report two cases of spinal, extraosseous, intradural ES/PNETs in adults who presented with back pain. Magnetic resonance imaging revealed contrast enhancing, intradural lesions in the area of the conus medullaris. The tumor in Case 1 was partially intramedullary, while the tumor in Case 2 was exclusively extramedullary. In both cases, the radiologic and intraoperative surgical impression favored ependymoma. The diagnosis of ES/PNET was established in both cases by histopathologic, immunohistochemical, and molecular analysis.
Middle atmospheric changes caused by the January and March 2012 solar proton events
Authors: Jackman C. H. , Randall C. E. , Harvey V. L. , Wang S. , Fleming E. L. , López-Puertas M. , Funke B. , Bernath P. F.
Published: January 2014

Abstract. The recent 23–30 January and 7–11 March 2012 solar proton event (SPE) periods were substantial and caused significant impacts on the middle atmosphere. These were the two largest SPE periods of solar cycle 24 so far. The highly energetic solar protons produced considerable ionization of the neutral atmosphere as well as HOx (H, OH, HO2) and NOx (N, NO, NO2). We compute a NOx production of 1.9 and 2.1 Gigamoles due to these SPE periods in January and March 2012, respectively, which places these SPE periods among the 12 largest in the past 50 yr. Aura Microwave Limb Sounder (MLS) observations of the peroxy radical, HO2, show significant enhancements of > 0.9 ppbv in the northern polar mesosphere as a result of these SPE periods. Both MLS measurements and Goddard Space Flight Center (GSFC) two-dimensional (2-D) model predictions indicated middle mesospheric ozone decreases of > 20% for several days in the northern polar region with maximum depletions > 60% over 1–2 days as a result of the HOx produced in both the January and March 2012 SPE periods. The SCISAT-1 Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE) and the Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instruments measured NO and NO2 (~ NOx), which indicated enhancements of over 20 ppbv in most of the northern polar mesosphere for several days as a result of these SPE periods. The GSFC 2-D model and the Global Modeling Initiative three-dimensional chemistry and transport model were used to predict the medium-term (~ months) influence and showed that the polar middle atmospheric ozone was most affected by these solar events in the Southern Hemisphere due to the increased downward motion in the fall and early winter. The downward transport moved the SPE-produced NOy to lower altitudes and led to predicted modest destruction of ozone (5–13%) in the upper stratosphere days to weeks after the March 2012 event. Polar total ozone reductions were predicted to be a maximum of 1.5% in 2012 due to these SPEs.
In situ physical and chemical characterisation of the Eyjafjallajökull aerosol plume in the free troposphere over Italy
Authors: Sandrini S. , Giulianelli L. , Decesari S. , Fuzzi S. , Cristofanelli P. , Marinoni A. , Bonasoni P. , Chiari M. , Calzolai G. , Canepari S. , Perrino C. , Facchini M. C.
Published: January 2014

Abstract. Continuous measurements of physical and chemical properties at the Mt. Cimone (Italy) GAW-WMO (Global Atmosphere Watch, World Meteorological Organization) Global Station (2165 m a.s.l.) have allowed the detection of the volcanic aerosol plume resulting from the Eyjafjallajökull (Iceland) eruption of spring 2010. The event affected the Mt. Cimone site after a transport over a distance of more than 3000 km. Two main transport episodes were detected during the eruption period, showing a volcanic fingerprint discernible against the free tropospheric background conditions typical of the site, the first from April 19 to 21 and the second from 18 to 20 May 2010. This paper reports the modification of aerosol characteristics observed during the two episodes, both characterised by an abrupt increase in fine and, especially, coarse mode particle number. Analysis of major, minor and trace elements by different analytical techniques (ionic chromatography, particle induced X-ray emission–particle induced gamma-ray emission (PIXE–PIGE) and inductively coupled plasma mass spectrometry (ICP-MS)) were performed on aerosols collected by ground-level discrete sampling. The resulting database allows the characterisation of aerosol chemical composition during the volcanic plume transport and in background conditions. During the passage of the volcanic plume, the fine fraction was dominated by sulphates, denoting the secondary origin of this mode, mainly resulting from in-plume oxidation of volcanic SO2. By contrast, the coarse fraction was characterised by increased concentration of numerous elements of crustal origin, such as Fe, Ti, Mn, Ca, Na, and Mg, which enter the composition of silicate minerals. Data analysis of selected elements (Ti, Al, Fe, Mn) allowed the estimation of the volcanic plume's contribution to total PM10, resulting in a local enhancement of up to 9.5 μg m−3, i.e. 40% of total PM10 on 18 May, which was the most intense of the two episodes. These results appear significant, especially in light of the huge distance of Mt. Cimone from the source, confirming the widespread diffusion of the Eyjafjallajökull ashes over Europe.
Longitudinal hotspots in the mesospheric OH variations due to energetic electron precipitation
Authors: Andersson M. E. , Verronen P. T. , Rodger C. J. , Clilverd M. A. , Wang S.
Published: January 2014

Abstract. Using Microwave Limb Sounder (MLS/Aura) and Medium Energy Proton and Electron Detector (MEPED/POES) observations between 2005–2009, we study the longitudinal response of nighttime mesospheric OH to radiation belt electron precipitation. Our analysis concentrates on geomagnetic latitudes from 55–72° N/S and altitudes between 70 and 78 km. The aim of this study is to better assess the spatial distribution of electron forcing, which is important for more accurate modelling of its atmospheric and climate effects. In the Southern Hemisphere, OH data show a hotspot, i.e. area of higher values, at longitudes between 150° W–30° E, i.e. poleward of the Southern Atlantic Magnetic Anomaly (SAMA) region. In the Northern Hemisphere, energetic electron precipitation-induced OH variations are more equally distributed with longitude. This longitudinal behaviour of OH can also be identified using Empirical Orthogonal Function analysis, and is found to be similar to that of MEPED-measured electron fluxes. The main difference is in the SAMA region, where MEPED appears to measure very large electron fluxes while MLS observations show no enhancement of OH. This indicates that in the SAMA region the MEPED observations are not related to precipitating electrons, at least not at energies >100 keV, but rather to instrument contamination. Analysis of selected OH data sets for periods of different geomagnetic activity levels shows that the longitudinal OH hotspot south of the SAMA (the Antarctic Peninsula region) is partly caused by strong, regional electron forcing, although atmospheric conditions also seem to play a role. Also, a weak signature of this OH hotspot is seen during periods of generally low geomagnetic activity, which suggests that there is a steady drizzle of high-energy electrons affecting the atmosphere, due to the Earth's magnetic field being weaker in this region.
Investigation of the effective peak supersaturation for liquid-phase clouds at the high-alpine site Jungfraujoch, Switzerland (3580 m a.s.l.)
Authors: Hammer E. , Bukowiecki N. , Gysel M. , Jurányi Z. , Hoyle C. R. , Vogt R. , Baltensperger U. , Weingartner E.
Published: January 2014

Abstract. Aerosols influence the Earth's radiation budget directly through absorption and scattering of solar radiation in the atmosphere but also indirectly by modifying the properties of clouds. However, climate models still suffer from large uncertainties as a result of insufficient understanding of aerosol-cloud interactions. At the high altitude research station Jungfraujoch (JFJ; 3580 m a.s.l., Switzerland) cloud condensation nuclei (CCN) number concentrations at eight different supersaturations (SS) from 0.24% to 1.18% were measured using a CCN counter during Summer 2011. Simultaneously, in-situ aerosol activation properties of the prevailing ambient clouds were investigated by measuring the total and interstitial (non-activated) dry particle number size distributions behind two different inlet systems. Combining all experimental data, a new method was developed to retrieve the so-called effective peak supersaturation SSpeak, as a measure of the SS at which ambient clouds are formed. A 17-month CCN climatology was then used to retrieve the SSpeak values also for four earlier summer campaigns (2000, 2002, 2004 and 2010) where no direct CCN data were available. The SSpeak values varied between 0.01% and 2.0% during all campaigns. An overall median SSpeak of 0.35% and dry activation diameter of 87 nm was observed. It was found that the difference in topography between northwest and southeast plays an important role for the effective peak supersaturation in clouds formed in the vicinity of the JFJ, while differences in the number concentration of potential CCN only play a minor role. Results show that air masses coming from the southeast (with the slowly rising terrain of the Aletsch Glacier) generally experience lower SSpeak values than air masses coming from the northwest (steep slope). The observed overall median values were 0.41% and 0.22% for northwest and southeast wind conditions, respectively, corresponding to literature values for cumulus clouds and shallow-layer clouds. These cloud types are consistent with weather observations routinely performed at the JFJ.
Reactivity of stabilized Criegee intermediates (sCI) from isoprene and monoterpene ozonolysis toward SO2 and organic acids
Authors: Sipilä M. , Jokinen T. , Berndt T. , Richters S. , Makkonen R. , Donahue N. M. , Mauldin III R. L. , Kurten T. , Paasonen P. , Sarnela N. , Ehn M. , Junninen H. , Rissanen M. P. , Thornton J. , Stratmann F. , Herrmann H. , Worsnop D. R. , Kulmala M. , Kerminen V.-M. , Petäjä T.
Published: January 2014

Abstract. Oxidation processes in Earth's atmosphere are tightly connected to many environmental and human health issues and are essential drivers for biogeochemistry. Until the recent discovery of the atmospheric relevance of stabilized Criegee intermediates (sCI), atmospheric oxidation processes were thought to be dominated by few main oxidants: ozone, hydroxyl radicals (OH), nitrate radicals and, e.g. over oceans, halogen atoms such as chlorine. Here, we report results from laboratory experiments at 293 K and atmospheric pressure focusing on sCI formation from the ozonolysis of isoprene and the most abundant monoterpenes (α-pinene and limonene), and subsequent reactions of the resulting sCIs with SO2 producing sulphuric acid (H2SO4). The measured sCI yields were (0.15 ± 0.07), (0.27 ± 0.12) and (0.58 ± 0.26) for the ozonolysis of α-pinene, limonene and isoprene, respectively. The ratio between the rate coefficient for the sCI loss (including thermal decomposition and the reaction with water vapour) and the rate coefficient for the reaction of sCI with SO2, k(loss) / k(sCI + SO2), was determined at relative humidities of 10% and 50%. Observed values represent the average reactivity of all sCIs produced from the individual alkene used in the ozonolysis. For the monoterpene derived sCIs, the relative rate coefficients k(loss) / k(sCI + SO2) were in the range (2.0–2.4) × 1012 molecule cm−3 and nearly independent on the relative humidity. This fact points to a minor importance of the sCI + H2O reaction in the case of the sCI arising from α-pinene and limonene. For the isoprene sCIs, however, the ratio k(loss) / k(sCI + SO2) was strongly dependent on the relative humidity. To explore whether sCIs could have a more general role in atmospheric oxidation, we investigated as an example the reactivity of acetone oxide (sCI from the ozonolysis of 2,3-dimethyl-2-butene) toward small organic acids, i.e. formic and acetic acid. Acetone oxide was found to react faster with the organic acids than with SO2; k(sCI + acid) / k(sCI + SO2) = (2.8 ± 0.3) for formic acid and k(sCI + acid) / k(sCI + SO2) = (3.4 ± 0.2) for acetic acid. This finding suggests that sCIs can play a role in the formation and loss of several atmospheric constituents besides SO2.
Constraining CO2 emissions from open biomass burning by satellite observations of co-emitted species: a method and its application to wildfires in Siberia
Authors: Konovalov I. B. , Berezin E. V. , Ciais P. , Broquet G. , Beekmann M. , Hadji-Lazaro J. , Clerbaux C. , Andreae M. O. , Kaiser J. W. , Schulze E.-D.
Published: January 2014

Abstract. A method to constrain carbon dioxide (CO2) emissions from open biomass burning by using satellite observations of co-emitted species and a chemistry-transport model (CTM) is proposed and applied to the case of wildfires in Siberia. CO2 emissions are assessed by means of an emission model assuming a direct relationship between the biomass burning rate (BBR) and the Fire Radiative Power (FRP) derived from the MODIS measurements. The key features of the method are (1) estimating the FRP-to-BBR conversion factors (α) for different vegetative land cover types by assimilating the satellite observations of co-emitted species into the CTM, (2) optimal combination of the estimates of α derived independently from satellite observations of different species (CO and aerosol in this study), and (3) estimation of the diurnal cycle of the fire emissions directly from the FRP measurements. Values of α for forest and grassland fires in Siberia and their uncertainties are estimated by using the IASI carbon monoxide (CO) retrievals and the MODIS aerosol optical depth (AOD) measurements combined with outputs from the CHIMERE mesoscale chemistry transport model. The constrained CO emissions are validated through comparison of the respective simulations with the independent data of ground based CO measurements at the ZOTTO site. Using our optimal regional-scale estimates of the conversion factors (which are found to be in agreement with the earlier published estimates obtained from local measurements of experimental fires), the total CO2 emissions from wildfires in Siberia in 2012 are estimated to be in the range from 262 to 477 Tg C, with the optimal (maximum likelihood) value of 354 Tg C. Sensitivity test cases featuring different assumptions regarding the injection height and diurnal variations of emissions indicate that the derived estimates of the total CO2 emissions in Siberia are robust with respect to the modelling options (the different estimates vary within less than 10% of their magnitude). The obtained CO2 emission estimates for several years are compared with the independent estimates provided by the GFED3.1 and GFASv1.0 global emission inventories. It is found that our "top-down" estimates for the total annual biomass burning CO2 emissions in the period from 2007 to 2011 in Siberia are by factors of 2.3 and 1.7 larger than the respective bottom-up estimates; these discrepancies cannot be fully explained by uncertainties in our estimates. There are also considerable differences in the spatial distribution of the different emission estimates; some of those differences have a systematic character and require further analysis.
Design and characterization of a smog chamber for studying gas-phase chemical mechanisms and aerosol formation
Authors: Wang X. , Liu T. , Bernard F. , Ding X. , Wen S. , Zhang Y. , Zhang Z. , He Q. , Lü S. , Chen J. , Saunders S. , Yu J.
Published: January 2014

Abstract. We describe here characterization of a new state-of-the-art smog chamber facility for studying atmospheric gas-phase and aerosol chemistry. The chamber consists of a 30 m3 fluorinated ethylene propylene (FEP) Teflon film reactor housed in a temperature-controlled enclosure equipped with black lamps as the light source. Temperature can be set in the range from −10 to 40 °C at accuracy of ±1 °C as measured by eight temperature sensors inside the enclosure and one just inside the reactor. Matrix air can be purified with non-methane hydrocarbons (NMHCs) < 0.5 ppb, NOx/O3/carbonyls < 1 ppb and particles < 1 cm−3. The photolysis rate of NO2 is adjustable between 0 and 0.49 min−1. At 298 K under dry conditions, the average wall loss rates of NO, NO2 and O3 were measured to be 1.41 × 10−4 min−1, 1.39 × 10−4 min−1 and 1.31 × 10−4 min−1, respectively, and the particle number wall loss rate was measured to be 0.17 h−1. Auxiliary mechanisms of this chamber are determined and included in the Master Chemical Mechanism to evaluate and model propene–NOx–air irradiation experiments. The results indicate that this new smog chamber can provide high-quality data for mechanism evaluation. Results of α-pinene dark ozonolysis experiments revealed secondary organic aerosol (SOA) yields comparable to those from other chamber studies, and the two-product model gives a good fit for the yield data obtained in this work. Characterization experiments demonstrate that our Guangzhou Institute of Geochemistry, Chinese Academy Sciences (GIG-CAS), smog chamber facility can be used to provide valuable data for gas-phase chemistry and secondary aerosol formation.
Mechanisms for the suppression of methane production in peatland soils by a humic substance analog
Authors: Ye R. , Keller J. K. , Jin Q. , Bohannan B. J. M. , Bridgham S. D.
Published: January 2014

Abstract. Methane (CH4) production is often impeded in many northern peatland soils, although inorganic terminal electron acceptors (TEAs) are usually present in low concentrations in these soils. Recent studies suggest that humic substances in wetland soils can be utilized as organic TEAs for anaerobic respiration and may directly inhibit CH4 production. Here we utilize the humic analog anthraquinone-2, 6-disulfonate (AQDS) to explore the importance of humic substances, and their effects on the temperature sensitivity of anaerobic decomposition, in two peatland soils. In a bog peat, AQDS was not instantly utilized as a TEA, but greatly inhibited the fermentative production of acetate, carbon dioxide (CO2), and hydrogen (H2), as well as CH4 production. When added together with glucose, AQDS was partially reduced after a lag period of 5 to 10 days. In contrast, no inhibitory effect of AQDS on fermentation was found in a fen peat and AQDS was readily reduced as an organic TEA. The addition of glucose and AQDS to both bog and fen peats caused complicated temporal dynamics in the temperature sensitivity of CH4 production, reflecting temporal changes in the temperature responses of other carbon processes with effects on methanogenesis. Our results show that the humic analog AQDS can act both as an inhibitory agent and a TEA in peatland soils. The high concentrations of humic substances in northern peatlands may greatly influence the effect of climate change on soil carbon cycling in these ecosystems.
Old carbon contributes to aquatic emissions of carbon dioxide in the Amazon
Authors: Vihermaa L. E. , Waldron S. , Garnett M. H. , Newton J.
Published: January 2014

Abstract. Knowing the rate that carbon is cycled is crucial to understanding the dynamics of carbon transfer pathways. Recent technical developments now support measurement of the 14C age of evaded CO2 from fluvial systems, which provides an important "fingerprint" of the source of C. Here we report the first direct measurements of the 14C age of effluxed CO2 from two small streams and two rivers within the Western Amazonian Basin. The rate of degassing and hydrochemical controls on degassing are also considered. We observe that CO2 efflux from all systems except the seasonal small stream was 14C-depleted relative to the contemporary atmosphere, indicating a~contribution from "old" carbon fixed before ~1955 AD. Further, "old" CO2 was effluxed from the perennial stream in the rainforest, unexpected as here connectivity with the contemporary C cycle is likely greatest. The effluxed gas represents all sources of CO2 in the aquatic system and thus we used end member analysis to identify the relative inputs of fossil, modern and intermediately-aged C. The most likely solutions indicated a contribution from fossil carbon sources of between 3 and 9% which we interpret as being derived from carbonate weathering. This is significant as the currently observed intensification of weather has the potential to increase the future release of old carbon, which can be subsequently degassed to the atmosphere, and so render older, slower C cycles faster. Thus 14C fingerprinting of evaded CO2 provides understanding essential to more accurately model the carbon cycle in the Amazon Basin.
A model–data intercomparison of simulated runoff in the contiguous United States: results from the North America Carbon Regional and Continental Interim-Synthesis
Authors: Schwalm C. R. , Huntinzger D. N. , Cook R. B. , Wei Y. , Baker I. T. , Neilson R. P. , Poulter B. , Caldwell P. , Sun G. , Tian H. Q. , Zeng N.
Published: January 2014

Abstract. Significant changes in the water cycle are expected under current global environmental change. Robust assessment of these changes at global scales is confounded by shortcomings in the observed record. Modeled assessments yield conflicting results which are linked to differences in model structure and simulation protocol. Here we compare simulated runoff from six terrestrial biosphere models (TBMs), five reanalysis products, and one gridded surface station product with observations from a network of stream gauges in the contiguous United States (CONUS) from 2001 to 2005. We evaluate the consistency of simulated runoff with stream gauge data at the CONUS and water resource region scale, as well as examining similarity across TBMs and reanalysis products at the grid cell scale. Mean runoff across all simulated products and regions varies widely (range: 71–356 mm yr-1) relative to observed continental-scale runoff (209 mm yr-1). Across all 12 products only two are within 10% of the observed value and only four exhibit Nash–Sutcliffe efficiency values in excess of 0.8. Region-level mismatch exhibits a weak pattern of overestimation in western and underestimation in eastern regions; although two products are systematically biased across all regions. In contrast, bias in a temporal sense, within region by water year, is highly consistent. Although gridded composite TBM and reanalysis runoff show some regional similarities for 2001–2005 with CONUS means, individual product values are highly variable. To further constrain simulated runoff and to link model-observation mismatch to model structural characteristics would require watershed-level simulation studies coupled with river routing schemes, standardized forcing data, and explicit consideration of water cycle management.