bluuebunny/crossref_metadata_2025 huggingface dataset:
Certificación energética de edificios en España y sus implicaciones económicas
Authors: Ruá M. J. , López-Mesa B.
Published: May 2012

Bajo la Directiva Europea sobre eficiencia energética de los edificios, los Estados Miembros deben desarrollar procedimientos para certificar energéticamente los edificios. Calener-VYP v1.0 es la única herramienta oficial española para certificar una elevada aptitud en eficiencia energética de edificios residenciales, por el método general. Tiene dos indicadores implementados, emisiones de CO2 y consumo de energía primaria. Sin embargo, en el proceso de otorgar la calificación energética, solamente se consideran las emisiones de CO2. Las implicaciones económicas de esto se estudian simulando viviendas con diferentes características constructivas e instalaciones en las doce zonas climáticas españolas y calculando sus costes. Los resultados muestran que una mejor calificación energética en Calener-VYP no implica necesariamente un menor coste de consumo energético. Por tanto, es necesario incluir el indicador consumo de energía primaria, ya que su ausencia significa que los costes energéticos no pueden ser usados como argumento para promover la eficiencia energética entre usuarios.
Automatic Text Classification from Labeled and Unlabeled Data
Authors: Jiang Eric P.
Published: May 2012

Automatic text classification is a process that applies information retrieval technology and machine learning algorithms to build models from pre-labeled training samples and then deploys the models to previously unseen documents for classification. Text classification has been widely applied in many fields ranging from Web page indexing, document filtering, and information security, to business intelligence mining. This chapter presents a semi-supervised text classification framework that is based on the radial basis function (RBF) neural networks. The framework integrates an Expectation Maximization (EM) process into a RBF network and can learn for classification effectively from a very small quantity of labeled training samples and a large pool of additional unlabeled documents. The effectiveness of the framework is demonstrated and confirmed by some experiments of the framework on two popular text classification corpora.
A Cognitive Framework for Core Language Understanding and its Computational Implementation
Authors: Massey L.
Published: May 2012

The author argues that the cognitive processes underlying language understanding may not be logico-deductive or inductive, at least not for basic forms of understanding such as the ability to determine the topics of a text document. To demonstrate this point, they present a human cognition inspired framework for core language understanding and its computational implementation. The framework exploits word related knowledge stored in Long Term Memory (LTM) as well as Short Term Memory (STM) limited capacity, neuromorphic spreading activation and neural activation decay to derive the topics of text. The computational model implementing the framework shows the potential of the approach by establishing that the topics generated by the model are as good as those generated by humans.
A Novel Approach for Designing Dynamical S-Boxes Using Hyperchaotic System
Authors: Peng Jun , Zhang Du , Liao Xiaofeng
Published: May 2012

In the information security field, the substitution boxes (S-boxes) have been extensively used in many cryptographic systems. This paper presents a novel approach for generating dynamically cryptographically S-boxes using a four-dimensional hyperchaotic Lorenz system. Within the algorithm, the initial condition is employed to drive the hyper-chaotic system to generate a chaotic sequence which is used to construct a chaotic key-dependent S-box. With different system initial conditions, many of distinct S-boxes can be obtained dynamically. Some cryptographic properties for a good S-box such as bijection, nonlinearity, SAC (Strict Avalanche Criterion), BIC (Bit Independence Criterion), and differential approximation probability are found to hold in the obtained S-boxes. The analytic results indicated that all the criteria for designing strong S-boxes can be achieved. The comparison of the proposed method for generating S-boxes with other chaos-based schemes indicates that our S-boxes have a better performance with respect to some properties. Finally, the authors give an example of a digital image encryption algorithm using their S-box and the results of image statistical analysis show that the algorithm has the desirable cryptographic properties.
Privacy Preserving Principal Component Analysis Clustering for Distributed Heterogeneous Gene Expression Datasets
Authors: Li Xin
Published: May 2012

In this paper, we present approaches to perform principal component analysis (PCA) clustering for distributed heterogeneous genomic datasets with privacy protection. The approaches allow data providers to collaborate together to identify gene profiles from a global viewpoint, and at the same time, protect the sensitive genomic data from possible privacy leaks. We then further develop a framework for privacy preserving PCA-based gene clustering, which includes two types of participants: data providers and a trusted central site (TCS). Two different methodologies are employed: Collective PCA (C-PCA) and Repeating PCA (R-PCA). The C-PCA requires local sites to transmit a sample of original data to the TCS and can be applied to any heterogeneous datasets. The R-PCA approach requires all local sites have the same or similar number of columns, but releases no original data. Experiments on five independent genomic datasets show that both C-PCA and R-PCA approaches maintain very good accuracy compared with the centralized scenario.
The “Beaver” International Competition and the Development of Digital Competences in Italian Pupils
Authors: Cartelli Antonio
Published: May 2012

This paper discusses the hypotheses, instruments, and processes for the introduction of suitable strategies for digital competence improvement in schools and for lifelong learning, together with the analysis of the first results on the use of a special questionnaire for the assessment. First, the evolution of the models for digital competence analysis and development the author has proposed in past years is reported. The features of the international “Beaver” competition are then explained. The author then blends the needs of the strategies for digital competence assessment included in the framework with the aims of the international competition. The comparison of the results obtained by a sample of students involved in two different editions of the competition is analyzed and the improvement of the pupils’ performances is shown. The relevance of a careful planning of the “beaver” questionnaire emerges and suggestions to the competition organizers for the articulation and structure of the questionnaire are proposed.
Pulmonary CCL18 Recruits Human Regulatory T Cells
Authors: Chenivesse Cécile , Chang Ying , Azzaoui Imane , Ait Yahia Saliha , Morales Olivier , Plé Coline , Foussat Arnaud , Tonnel André-Bernard , Delhem Nadira , Yssel Hans , Vorng Han , Wallaert Benoit , Tsicopoulos Anne
Published: May 2012

CCL18 is both a constitutively expressed and an inducible chemokine, whose role in the inflammatory reaction is poorly known. The aim of this study was to evaluate whether CCL18 has the capacity to attract human T cells with a regulatory function (regulatory T cells [Treg]). Results from chemotaxis assays performed on different types of Treg showed that CD4+CD25+CD127low cells, but neither T regulatory type 1 clones nor Treg differentiated in vitro with anti-CD3/CD46 mAbs, were recruited by CCL18 in a dose-dependent manner. CCL18-recruited memory CD4+ T cells were enriched in CD25high, CD25+CD127low, latency-associated peptide/TGF-β1, and CCR4-expressing T cells, whereas there was no enrichment in Foxp3+ cells as compared with controls. Stimulated CCL18-recruited memory T cells produced significantly increased amounts of the regulatory cytokines IL-10 and TGF-β1, as well as IL-4, but not IFN-γ and IL-17. Cell surface CCL18 binding was found predominantly on IL-10+ (26.3 ± 5.8%) and on a few latency-associated peptide/TGF-β1+ (18.1 ± 1.9%) and IL-4+ (14.5 ± 2.9%) memory T cells. In an in vivo model of SCID mice grafted with human skin and reconstituted with autologous PBMCs, the intradermal injection of CCL18 led to the cutaneous recruitment of CD4+, CD25+, and IL-10+ cells, but not Foxp3+ cells. Furthermore, CCL18-recruited memory T cells inhibited the proliferation of CD4+CD25− effector T cells through an IL-10–dependent mechanism. These data suggest that CCL18 may contribute to maintaining tolerance and/or suppressing deleterious inflammation by attracting memory Tregs into tissues, particularly in the lung, where it is highly and constitutively expressed.
Purinergic P2X7 Receptor Drives T Cell Lineage Choice and Shapes Peripheral γδ Cells
Authors: Frascoli Michela , Marcandalli Jessica , Schenk Ursula , Grassi Fabio
Published: May 2012

TCR signal strength instructs αβ versus γδ lineage decision in immature T cells. Increased signal strength of γδTCR with respect to pre-TCR results in induction of the γδ differentiation program. Extracellular ATP evokes physiological responses through purinergic P2 receptors expressed in the plasma membrane of virtually all cell types. In peripheral T cells, ATP released upon TCR stimulation enhances MAPK activation through P2X receptors. We investigated whether extracellular ATP and P2X receptors signaling tuned TCR signaling at the αβ/γδ lineage bifurcation checkpoint. We show that P2X7 expression was selectively increased in immature γδ+CD25+ cells. These cells were much more competent to release ATP than pre–TCR-expressing cells following TCR stimulation and Ca2+ influx. Genetic ablation as well as pharmacological antagonism of P2X7 resulted in impaired ERK phosphorylation, reduction of early growth response (Egr) transcripts induction, and diversion of γδTCR-expressing thymocytes toward the αβ lineage fate. The impairment of the ERK-Egr-inhibitor of differentiation 3 (Id3) signaling pathway in γδ cells from p2rx7−/− mice resulted in increased representation of the Id3-independent NK1.1-expressing γδ T cell subset in the periphery. Our results indicate that ATP release and P2X7 signaling upon γδTCR expression in immature thymocytes constitutes an important costimulus in T cell lineage choice through the ERK-Egr-Id3 signaling pathway and contributes to shaping the peripheral γδ T cell compartment.
Gadolinium Compounds Signaling through TLR 4 and TLR 7 in Normal Human Macrophages: Establishment of a Proinflammatory Phenotype and Implications for the Pathogenesis of Nephrogenic Systemic Fibrosis
Authors: Wermuth Peter J. , Jimenez Sergio A.
Published: May 2012

Nephrogenic systemic sibrosis is a progressive disorder occurring in some renal insufficiency patients exposed to gadolinium-based contrast agents (GdBCA). Previous studies demonstrated that the GdBCA Omniscan upregulated several innate immunity pathways in normal differentiated human macrophages, induced rapid nuclear localization of the transcription factor NF-κB, and increased the expression and production of numerous profibrotic/proinflammatory cytokines, chemokines, and growth factors. To further examine GdBCA stimulation of the innate immune system, cultured human embryonic kidney 293 cells expressing one of seven different human TLRs or one of two human nucleotide-binding oligomerization domain-like receptors were exposed in vitro for 24 h to various GdBCA. The signaling activity of each compound was evaluated by its ability to activate an NF-κB–inducible reporter gene. Omniscan and gadodiamide induced strong TLR4- and TLR7-mediated reporter gene activation. The other Gd compounds examined failed to induce reporter gene activation. TLR pathway inhibition using chloroquine or an inhibitor of IL-1R–associated kinases 1 and 4 in normal differentiated human macrophages abrogated Omniscan-induced gene expression. Omniscan and gadodiamide signaling via TLRs 4 and 7 resulted in increased production and expression of numerous proinflammatory/profibrotic cytokines, chemokines, and growth factors, including CXCL10, CCL2, CCL8, CXCL12, IL-4, IL-6, TGF-β, and vascular endothelial growth factor. These observations suggest that TLR activation by environmental stimuli may participate in the pathogenesis of nephrogenic systemic fibrosis and of other fibrotic disorders including systemic sclerosis.
GITR Ligand Provided by Thrombopoietic Cells Inhibits NK Cell Antitumor Activity
Authors: Placke Theresa , Salih Helmut R. , Kopp Hans-Georg
Published: May 2012

Thrombocytopenia inhibits tumor growth and especially metastasis in mice, whereas additional depletion of NK cells reverts this antimetastatic phenotype. It has therefore been speculated that platelets may protect hematogenously disseminating tumor cells from NK-dependent antitumor immunity. Tumor cells do not travel through the blood alone, but are rapidly coated by platelets, and this phenomenon has been proposed to shield disseminating tumor cells from NK-mediated lysis. However, the underlying mechanisms remain largely unclear. In this study, we show that megakaryocytes acquire expression of the TNF family member glucocorticoid-induced TNF-related ligand (GITRL) during differentiation, resulting in GITRL expression by platelets. Upon platelet activation, GITRL is upregulated on the platelet surface in parallel with the α-granular activation marker P-selectin. GITRL is also rapidly mobilized to the platelet surface following interaction with tumor cells, which results in platelet coating. Whereas GITRL, in the fashion of several other TNF family members, is capable of transducing reverse signals, no influence on platelet activation and function was observed upon GITRL triggering. However, platelet coating of tumor cells inhibited NK cell cytotoxicity and IFN-γ production that could partially be restored by blocking GITR on NK cells, thus indicating that platelet-derived GITRL mediates NK-inhibitory forward signaling via GITR. These data identify conferment of GITRL pseudoexpression to tumor cells by platelets as a mechanism by which platelets may alter tumor cell immunogenicity. Our data thus provide further evidence for the involvement of platelets in facilitating evasion of tumor cells from NK cell immune surveillance.
Donor B Cells in Transplants Augment Clonal Expansion and Survival of Pathogenic CD4+ T Cells That Mediate Autoimmune-like Chronic Graft-versus-Host Disease
Authors: Young James S. , Wu Tao , Chen Yuhong , Zhao Dongchang , Liu Hongjun , Yi Tangsheng , Johnston Heather , Racine Jeremy , Li Xiaofan , Wang Audrey , Todorov Ivan , Zeng Defu
Published: May 2012

We reported that both donor CD4+ T and B cells in transplants were required for induction of an autoimmune-like chronic graft-versus-host disease (cGVHD) in a murine model of DBA/2 donor to BALB/c recipient, but mechanisms whereby donor B cells augment cGVHD pathogenesis remain unknown. In this study, we report that, although donor B cells have little impact on acute GVHD severity, they play an important role in augmenting the persistence of tissue damage in the acute and chronic GVHD overlapping target organs (i.e., skin and lung); they also markedly augment damage in a prototypical cGVHD target organ, the salivary gland. During cGVHD pathogenesis, donor B cells are activated by donor CD4+ T cells to upregulate MHC II and costimulatory molecules. Acting as efficient APCs, donor B cells augment donor CD4+ T clonal expansion, autoreactivity, IL-7Rα expression, and survival. These qualitative changes markedly augment donor CD4+ T cells’ capacity in mediating autoimmune-like cGVHD, so that they mediate disease in the absence of donor B cells in secondary recipients. Therefore, a major mechanism whereby donor B cells augment cGVHD is through augmenting the clonal expansion, differentiation, and survival of pathogenic CD4+ T cells.
Intramedullary Pilomyxoid Astrocytoma with Intracerebral Metastasis Exhibiting Oligoden-Droglioma-Like Features
Authors: Eigenbrod Sabina , Thon Niklas , Jansen Nathalie , Janssen Hendrik , Mielke Janina , Ruiter Michael , la Fougère Christian , Peraud Aurelia , Egensperger Rupert , Kretzschmar Hans
Published: May 2012

Intramedullary glioma are rare and their biological behaviour can differ from their cerebral counterparts. Pilomyxoid astrocytoma (PMA, WHO grade II), predominantly occur in the hypothalamic/chiasmatic region of infants and children. The few reported cases of pediatric intramedullary PMA displayed a particularly aggressive behavior. Here, we report a diagnostically challenging case of a five year old female patient presenting with intramedullary glioma and local tumor recurrence three years later. Twelve years after the initial manifestation, a second tumor was found intracerebrally. We performed a comprehensive histological, molecular pathological and imaging analysis of the tumors from both localizations. The results revealed a metastasizing PMA with unique histological and genetic features. Our study indicates that PMA comprise a heterogeneous group including aggressive subtypes which may not be compatible with the current classification according to WHO grade II. Furthermore, the case emphasizes the increasing relevance of molecular pathological markers complementing classic histo-logical diagnosis.
Dimensions and Boundaries: Comparative Analysis of Occupational Structures Using Social Network and Social Interaction Distance Analysis
Authors: Griffiths Dave , Lambert Paul S.
Published: May 2012

This paper analyses social interactions between detailed occupational positions as a means of exploring social and occupational inequalities. Two methods are employed: descriptive techniques of social network analysis, and a well-established modelling approach (the ‘CAMSIS’ method of ‘Social Interaction Distance’ analysis). New results on occupational connections are presented for four countries - the United States, Romania, the Philippines and Venezuela – illustrative of a range of socio-economic regimes. Our analyses use detailed occupational measures based upon census data from 2000 to 2002, and we also use data on educational attainment, cross-classified by occupational positions. A broad, singular dimension of social stratification is shown to be the principal element of the structure of social interactions between occupations, but the methods also reveal the social role of various boundaries in occupational interaction patterns (defined by work location, education, and gender). We argue that such distinctions imply that occupational data at a disaggregated level can provide a more thorough understanding of social structure than is observable using amalgamated occupational schemes.
A Tale of Two Analyses: The Use of Archived Qualitative Data
Authors: Haynes Jo , Jones Demelza
Published: May 2012

This article provides a unique contribution to the debates about archived qualitative data by drawing on two uses of the same data - British Migrants in Spain: the Extent and Nature of Social Integration, 2003-2005 - by Jones (2009) and Oliver and O'reilly (2010) , both of which utilise Bourdieu's concepts analytically and produce broadly similar findings. We argue that whilst the insights and experiences of those researchers directly involved in data collection are important resources for developing contextual knowledge used in data analysis, other kinds of critical distance can also facilitate credible data use. We therefore challenge the assumption that the idiosyncratic relationship between context, reflexivity and interpretation limits the future use of data. Moreover, regardless of the complex genealogy of the data itself, given the number of contingencies shaping the qualitative research process and thus the potential for partial or inaccurate interpretation, contextual familiarity need not be privileged over other aspects of qualitative praxis such as sustained theoretical insight, sociological imagination and methodological rigour.
Debating Empirical Questions on the Internet: Rival Claims about Crowd Sizes of the Glenn Beck/Stewart-Colbert Rallies
Authors: Gunter Whitney D. , Best Joel
Published: May 2012

Analysts argue that the Internet can democratize the construction of social problems and reduce claimsmakers’ dependence on coverage in traditional media. This paper examines Internet claims about the relative sizes of 2010 rallies on the Washington, D.C. National Mall hosted by Glenn Beck and Jon Stewart/Stephen Colbert. Because crowd size is understood to be an index for the popularity of social causes, and because the two rallies were taken to stand for opposing positions in the culture war, numerous advocates offered competing analyses of the crowds’ relative sizes. Analysis of these claims suggests that the Internet offers a forum where a host of arguments and evidence can be presented in a short period of time. Yet, although crowd size is an empirical issue, there was little effort to reconcile competing arguments and arrive at general agreement, and, without media coverage, these claims failed to attract much public attention.
Getting up - Staying Up? - Exploring Trajectories in Household Incomes between 1992 and 2006
Authors: Byrne David
Published: May 2012

The objectives of this article are primarily methodological. It demonstrates how the use of ‘combined truth tables’ derived by deploying the tools of Qualitative Comparative Analysis (QCA) enables us to explore the multiple trajectories of cases through time. This approach is presented as an alternative to the use of log-linear methods which develop the model, which ‘fits’ the data. Despite urges to caution, such models are frequently understood as descriptions of causation. Log-linear models cannot deal with multiple causation and have serious problems in handling complex causation. The approach suggested here allows exploration of both multiple and complex causation without moving into the difficult terrain of causal assertion. The approach is demonstrated through an exploration, using British Household Panel data, of patterns of mobility for individuals in relation to household incomes across time comparing their household income location in 1992 with their household income location in 2006 taking into account gender, age, education, social class, being in a couple, and the employment status of partner. A subsidiary argument of the piece is that it is household income which should provide a primary focus for attention to patterns of social mobility over time.
The 2011 ‘Riots’: Reflections on the Fall and Rise of Community
Authors: Wallace Andrew
Published: May 2012

This paper argues that sociological engagement with the 2011 summer unrest in England has thus far overlooked an important aspect of the ‘rioting’: the troubling by ‘rioters’ of the communitarian publics and moral geographies which constitute marginalised city-space. In response to this knowledge gap, this paper seeks to argue that the unrest was transgressive of governance logics which construct inner city ‘communities’ as spatialised units housing ethno-class legacies and sociations; environments in which remoralised urban citizenships are increasingly being located by policymakers and urban managers. A key goal of the paper is to briefly unpack and situate these projects within repertoires of urban management within the neoliberal city. Another goal is to reflect on media and policy responses to the ‘riots’ to illustrate the existence and reinforcement of these projects, evinced by the popular construction of ‘rioting’ as contravening ordered community practice. By mapping the representation and vectoring of community within these narratives either as a fallen or resurgent entity, the paper contends that they provide important insights into the contested socio-moral management strategies increasingly brought to bear on the urban poor. The paper also considers foregrounding such urban strategies as context to be crucial for a sociological framing of the unrest and the repudiation of depoliticised victim-blaming accounts. The paper also briefly reflects on the periodised, networked and disparate practices of the ‘riots’ to stress the dangers of boxing unrest, or indeed rest, within narrow spatial or behavioural boundaries or essentialised causal categories. Amongst other things, the diffuseness and multi-scalar nature of the ‘riots’ revealed the deficiency of this normative reading of the registers of urban citizenship. In this sense, the paper suggests that some academic commentary on the ‘riots’ has been in danger of reinforcing the same localised and residualised cartographies of citizenship generated by communitarian governance strategies at a time when sociologists should be exposing and resisting such articulations. In developing this discussion therefore, the paper seeks to challenge the formulations and boundaries of ‘community’ as conceptualised by urban governance strategies driving the functional reproduction of neoliberal marginalities.
Space, Buildings and the Life Worlds of Home-Based Workers: Towards Better Design
Authors: Holliss Frances
Published: May 2012

This article draws on recent research into the architecture of home-based work, the working practices of the home-based workforce and the range and types of buildings they inhabit. The initial project was conducted in 2005-07. It involved 76 informants, from urban, suburban and rural contexts in England: a London Borough, a London suburb and a West Sussex village. Follow-on research was conducted in London in 2009-11. Originating in architecture, the research employed a number of visual methods, including photography, orthogonal drawing and diagram-making. While these visual methods are commonplace in architecture, they are normally used to portray idealized buildings and interiors. People and their everyday lives are usually absent. In contrast, as is more typical of sociology, a primary concern of this research was to understand the ordinary daily lives of people who either lived at their workplace or worked in their homes. The research sought a better understanding of the historical and contemporary significance of the spaces and buildings that would be of use to this workforce, one which could give a voice to contemporary home-based workers across the social spectrum and in a wide variety of occupations. Representing their life-worlds visually has been central to this aim.
Performing in a Night-Time Leisure Venue: A Visual Analysis of Erotic Dance
Authors: Pilcher Katy
Published: May 2012

This article analyses a range of different meanings attached to images of erotic dance, with a particular focus on the ‘impression management’ ( Goffman 1959 ) enacted by dancers. It presents a visual analysis of the work of a female erotic performer in a lesbian erotic dance venue in the UK. Still photographs, along with observational data and interviews, convey the complexity and skill of an erotic dancer's diverse gendered and sexualised performances. The visual data highlights the extensive ‘aesthetic labour’ ( Nickson et al. 2001 ) and ‘emotional labour’ ( Hochschild 1983 ) the dancer must put in to constructing her work ‘self’. However, a more ambitious use of the visual is identified: the dancer's own use of images of her work. This use of the visual by dancers themselves highlights a more complex ‘impression management’ strategy undertaken by a dancer and brings into question the separation of ‘real’ and ‘work’ ‘selves’ in erotic dance.
Geographic and seasonal distributions of CO transport pathways and their roles in determining CO centers in the upper troposphere
Authors: Huang L. , Fu R. , Jiang J. H. , Wright J. S. , Luo M.
Published: May 2012

Abstract. Past studies have identified a variety of pathways by which carbon monoxide (CO) may be transported from the surface to the tropical upper troposphere (UT); however, the relative roles that these transport pathways play in determining the distribution and seasonality of CO in the tropical UT remain unclear. We have developed a method to automate the identification of two pathways ("local convection" and "advection within the lower troposphere (LT) followed by convective vertical transport") involved in CO transport from the surface to the UT. This method is based on the joint application of instantaneous along-track, co-located, A-Train satellite measurements. Using this method, we find that the locations and seasonality of the UT CO maxima in the tropics were strongly correlated with the frequency of local convective transport during 2007. We also find that the "local convection" pathway (convective transport that occurred within a fire region) typically transported significantly more CO to the UT than the "LT advection → convection" pathway (advection of CO within the LT from a fire region to a convective region prior to convective transport). To leading order, the seasonality of CO concentrations in the tropical UT reflected the seasonality of the "local convection" transport pathway during 2007. The UT CO maxima occurred over Central Africa during boreal spring and over South America during austral spring. Occurrence of the "local convection" transport pathway in these two regions also peaked during these seasons. During boreal winter and summer, surface CO emission and convection were located in opposite hemispheres, which limited the effectiveness of transport to the UT. During these seasons, CO transport from the surface to the UT typically occurred via the "LT advection → convection" pathway.
The equilibrium response to idealized thermal forcings in a comprehensive GCM: implications for recent tropical expansion
Authors: Allen R. J. , Sherwood S. C. , Norris J. R. , Zender C. S.
Published: May 2012

Abstract. Several recent studies have shown the width of the tropical belt has increased over the last several decades. The mechanisms driving tropical expansion are not well known and the recent expansion is underpredicted by state-of-the art GCMs. We use the CAM3 GCM to investigate how tropical width responds to idealized atmospheric heat sources, focusing on zonal displacement of the tropospheric jets. The heat sources include global and zonally restricted lower-tropospheric warmings and stratospheric coolings, which coarsely represent possible impacts of ozone or aerosol changes. Similar to prior studies with simplified GCMs, we find that stratospheric cooling – particularly at high-latitudes – shifts jets poleward and excites Northern and Southern Annular Mode (NAM/SAM)-type responses. We also find, however, that modest heating of the midlatitude boundary layer drives a similar response; heating at high latitudes provokes a weaker, equatorward shift and tropical heating produces no shift. Over 70 % of the variance in annual mean jet displacements across 27 experiments is accounted for by a newly proposed "Expansion Index", which compares mid-latitude tropospheric warming to that at other latitudes. We find that previously proposed factors, including tropopause height and tropospheric stability, do not fully explain the results. Results suggest recently observed tropical expansion could have been driven not only by stratospheric cooling, but also by mid-latitude heating sources due for example to ozone or aerosol changes.
Implementation of dust emission and chemistry into the Community Multiscale Air Quality modeling system and initial application to an Asian dust storm episode
Authors: Wang K. , Zhang Y. , Nenes A. , Fountoukis C.
Published: May 2012

Abstract. The US Environmental Protection Agency (EPA)'s Community Multiscale Air Quality (CMAQ) modeling system version 4.7 is further developed to enhance its capability in simulating the photochemical cycles in the presence of dust particles. The new model treatments implemented in CMAQ v4.7 in this work include two online-dust emission schemes, nine dust-related heterogeneous reactions, an updated aerosol inorganic thermodynamic module ISORROPIA II with an explicit treatment of crustal species, and the interface between ISORROPIA II and the new dust treatments. The resulting improved CMAQ (referred to as CMAQ-Dust), offline-coupled with the Weather Research and Forecast model (WRF), are applied to the April 2001 dust storm episode over the trans-Pacific domain to examine the impact of new model treatments and understand associated uncertainties. WRF/CMAQ-Dust produces reasonable spatial distribution of dust emissions and captures the dust outbreak events, with the total dust emissions of ∼111 and 223 Tg when the erodible fraction is assumed to be 0.5 and 1.0, respectively, for the April 2001 episode. The model system can reproduce well observed meteorological and chemical concentrations, with significant improvements for suspended particulate matter (PM), PM with aerodynamic diameter of 10 μm and aerosol optical depth than default CMAQ v4.7. The sensitivity studies show that the inclusion of crustal species reduces the concentration of PM with aerodynamic diameter of 2.5 μm (PM2.5) over polluted areas. The heterogeneous chemistry occurring on dust particles acts as a sink for some species (e.g., as a lower limit estimate, O3 by up to 3.8 ppb (∼9%) and SO2 by up to 0.3 ppb (∼27%)) and as a source for some others (e.g., fine-mode SO42− by up to 1.1 μg m−3 (∼12%) and PM2.5 by up to 1.4 μg m−3 (∼3%) over the domain. The long-range transport of Asian pollutants can enhance the background concentrations of gases by up to 3% and aerosol species by up to 20% in the US.
A three-dimensional variational data assimilation system for multiple aerosol species with WRF/Chem and an application to PM2.5 prediction
Authors: Li Z. , Zang Z. , Li Q. B. , Chao Y. , Chen D. , Ye Z. , Liu Y. , Liou K.-N.
Published: May 2012

Abstract. A three-dimensional variational data assimilation (3-DVAR) algorithm for aerosols in a WRF/Chem model is presented. The WRF/Chem model uses the MOSAIC (Model for Simulating Aerosol Interactions and Chemistry) scheme, which explicitly treats eight major species (elemental/black carbon, organic carbon, nitrate, sulfate, chloride, ammonium, sodium, and the sum of other inorganic, inert mineral and metal species) and represents size distributions using a sectional method with four size bins. The 3-DVAR scheme is formulated to take advantage of the MOSAIC scheme in providing comprehensive analyses of specie concentrations and size distributions. To treat the large number of state variables associated with the MOSAIC scheme, this 3-DVAR algorithm first determines the analysis increments of the total mass concentrations of the eight species, defined as the sum of the mass concentrations across all size bins, and then distributes the analysis increments over four size bins according to the background error variances. The number concentrations for each size bin are adjusted based on the ratios between the mass and number concentrations of the background state. This system has been applied to the analysis and prediction of PM2.5 in the Los Angeles basin during the CalNex 2010 field experiment, with assimilation of surface PM2.5 and speciated concentration observations. The results demonstrate that the data assimilation significantly reduces the errors in comparison with a down scaling simulation and improved forecasts of the concentrations of PM2.5 as well as individual species for up to 24 h. Some implementation difficulties and limitations of the system are also discussed.
Occurrence of lower cloud albedo in ship tracks
Authors: Chen Y.-C. , Christensen M. W. , Xue L. , Sorooshian A. , Stephens G. L. , Rasmussen R. M. , Seinfeld J. H.
Published: May 2012

Abstract. The concept of geoengineering by marine cloud brightening is based on seeding marine stratocumulus clouds with sub-micrometer sea-salt particles to enhance the cloud droplet number concentration and cloud albedo, thereby producing a climate cooling effect. The efficacy of this as a strategy for global cooling rests on the extent to which aerosol-perturbed marine clouds will respond with increased albedo. Ship tracks, cloud regions impacted by ship exhaust, are a well-known manifestation of the effect of aerosol injection on marine clouds. We present here an analysis of the albedo responses in ship tracks, based on in situ aircraft measurements and three years of satellite observations of 589 individual ship tracks. It is found that the sign (increase or decrease) and magnitude of the albedo response in ship tracks depends on the mesoscale cloud structure, the free tropospheric humidity, and cloud top height. In a closed cell structure (cloud cells ringed by a perimeter of clear air), nearly 30% of ship tracks exhibited a decreased albedo. Detailed cloud responses must be accounted for in global studies of the potential efficacy of sea-spray geoengineering as a means to counteract global warming.
Consistency of long-term elemental carbon trends from thermal and optical measurements in the IMPROVE network
Authors: Chen L.-W. A. , Chow J. C. , Watson J. G. , Schichtel B. A.
Published: May 2012

Abstract. Decreasing trends of elemental carbon (EC) have been reported at US Interagency Monitoring of Protected Visual Environments (IMPROVE) network since 1990, consistent with the phase-in of cleaner engines, residential biomass burning technologies, and prescribed burning methods. The EC trends from the past decade are cautioned due to an upgrade of IMPROVE carbon analyzers and the thermal/optical analysis protocol since 2005. Filter reflectance (τR) values measured as part of the carbon analysis were retrieved from archived data and compared with EC for 65 sites with more complete records from 2000 to 2009. The EC-τR relationships show only minor changes of EC quantified by the original and upgraded instruments for most of the IMPROVE samples. EC and τR show universal decreasing trends across the US. The EC and τR trends are correlated well, with national average downward trends of 4.5% and 4.1% (of the 2000–2004 baseline medians) per year, respectively. The consistency between independent EC and τR trends adds to the weight-of-evidence that EC reductions are real rather than an artifact of the measurement process.
Modelling of optical emissions enhanced by the HF pumping of the ionospheric F-region
Authors: Sergienko T. , Gustavsson B. , Brändström U. , Axelsson K.
Published: May 2012

Abstract. Strong enhancement of the optical emissions with excitation threshold from 1.96 eV (630.0 nm from O(1D)) up to 18.75 eV (427.8 nm from N2+(1NG)) have been observed during experiments of the ionosphere modification by high power HF radio waves. Analysis of the optical emission ratios showed clearly that a significant part of the ionospheric electrons have to be accelerated to energies above 30 eV and more in the region where the HF radio wave effectively interacts with the ionospheric plasma. The Monte-Carlo model of electron transport and the optical emission model were used to study the dependence of the optical emission intensity on the acceleration electron parameters. We obtained the following results from analysis of the enhanced intensities of the four optical emissions (630.0, 557.7, 844.6 and 427.8 nm) observed in the EISCAT heating experiment on 10 March 2002. The 630.0 emission with an excitation threshold of 1.96 eV is formed predominately by the thermal electrons, where the accelerated electrons play a minor role in the excitation of this emission. In order to explain the experimentally observed intensity ratios, the accelerated electrons must gain energies of more than 60 eV. For accelerated electrons with a power law energy dependence, the efficiency of the optical emission excitation depends on the exponent defining the shape of the electron spectra. However, an agreement with the observed emission intensities is achieved for exponent values not less than zero. Moreover, increasing the exponent to higher values does not affect the emission intensity ratios.
Variation in stable carbon and oxygen isotopes of individual benthic foraminifera: tracers for quantifying the vital effect
Authors: Ishimura T. , Tsunogai U. , Hasegawa S. , Nakagawa F. , Oi T. , Kitazato H. , Suga H. , Toyofuku T.
Published: May 2012

Abstract. Stable carbon and oxygen isotopic compositions (δ13C and δ18O) of benthic foraminiferal carbonate shells have been used to reconstruct past bottom water environments. However, the details of factors controlling the isotopic disequilibrium between the shells and the surrounding bottom seawater (the vital effect) are still ambiguous. In this study, we analyzed the isotopic composition of individual benthic foraminifera of multiple species by using a customized high-precision analytical system, and found that the magnitude of the vital effect in different species is correlated with inter-individual variations. As a result, we can choose suitable species as bottom water proxies by using the inter-individual isotopic variations. In addition, by using the simplified interpretation of the vital effect established in this study, we can reconstruct the δ13C values of dissolved inorganic carbon in bottom water by correcting foraminiferal isotopic compositions for the isotopic shift resulting from the vital effect. Our findings will allow the use of isotope data for all benthic foraminifera as more reliable proxies for reconstructing past bottom water conditions and evaluating global carbon cycling.
An ensemble-based approach to climate reconstructions
Authors: Bhend J. , Franke J. , Folini D. , Wild M. , Brönnimann S.
Published: May 2012

Abstract. Data assimilation is a promising approach to obtain climate reconstructions that are both consistent with observations of the past and with our understanding of the physics of the climate system as represented in the climate model used. Here, we investigate the use of ensemble square root filtering (EnSRF) – a technique used in weather forecasting – for climate reconstructions. We constrain an ensemble of 29 simulations from an atmosphere-only general circulation model (GCM) with 37 pseudo-proxy temperature time series. Assimilating spatially sparse information with low temporal resolution (semi-annual) improves the representation of not only temperature, but also other surface properties, such as precipitation and even upper air features such as the intensity of the northern stratospheric polar vortex or the strength of the northern subtropical jet. Given the sparsity of the assimilated information and the limited size of the ensemble used, a localisation procedure is crucial to reduce "overcorrection" of climate variables far away from the assimilated information.
Extreme flood response to short-duration convective rainfall in South-West Germany
Authors: Ruiz-Villanueva V. , Borga M. , Zoccatelli D. , Marchi L. , Gaume E. , Ehret U.
Published: May 2012

Abstract. The 2 June 2008 flood-producing storm on the Starzel river basin in South-West Germany is examined as a prototype for organized convective systems that dominate the upper tail of the precipitation frequency distribution and are likely responsible for the flash flood peaks in Central Europe. The availability of high-resolution rainfall estimates from radar observations and a rain gauge network, together with indirect peak discharge estimates from a detailed post-event survey, provided the opportunity to study in detail the hydrometeorological and hydrological mechanisms associated with this extreme storm and the ensuing flood. Radar-derived rainfall, streamgauge data and indirect estimates of peak discharges are used along with a distributed hydrologic model to reconstruct hydrographs at multiple locations. Observations and model results are combined to examine two main questions, (i) assessment of the distribution of the runoff ratio for the 2008 flash flood and how it compares with other less severe floods; and (ii) analysis of how the spatial and temporal distribution of the extreme rainfall, and more specifically storm motion, controls the flood response. It is shown that small runoff ratios (less than 20%) characterized the runoff response and that these values are in the range of other, less extreme, flood events. The influence of storm structure, evolution and motion on the modeled flood hydrograph is examined by using the "spatial moments of catchment rainfall". It is shown that downbasin storm motion (in the range of 0.7–0.9 m s−1) had a noticeable impact on flood response by increasing the modeled flood peak by 13%.
Summer sea ice in the recent Arctic: morphological properties in the Pacific sector from the CHINARE 2010 cruise
Authors: Xie H. , Lei R. , Ke C. , Wang H. , Li Z. , Zhao J. , Ackley S. F.
Published: May 2012

Abstract. The Chinese National Arctic Research Expedition (CHINARE) in the summer 2010, primarily from 21 July to 28 August, in the ice zone of Arctic Pacific Sector, between 150° W to 180° W to 88.5° N, conducted comprehensive scientific studies on atmosphere-ice-ocean interactions, using icebreaker R.V. Xuelong. Measurements made included underway visual observations of snow and ice conditions at half-hourly time scale and EM31-measured ice thickness at one 12-day and eight short-term (3–4 h each) ice stations. The visual observation data are compared with AMSR-E ice concentration, ice thickness measured by a hanging EM31 from the vessel, and video-recorded image-derived ice concentration and pond coverage. A grid of 8 profiles of ice thickness measurements (four repeats) was conducted at the 12-day ice station (∼86°50' N–87°20' N) in the central Arctic and an average 2 cm day−1 melt rate, primarily bottom melt, was found, after surface melting had almost ceased. The high bottom melt rate, as compared with previous results from other studies, is consistent with the high floe speed (mean 0.17 m s−1) that is also larger than that previously reported. We also found that the daily AMSR-E ice concentration data can be used to map the marginal ice zone (MIZ) and its change. There are clear differences between the MIZ and pack ice zone in terms of ice concentration, thickness, ice type, floe size, as well as pond coverage. Results indicate that, as compared with the 2005 data from the Healy/Oden Trans-Arctic Expedition for the Arctic Pacific Sector (9 August to 10 September), the 2010 was first-year ice dominant (vs. the multiyear ice dominant in 2005), 70% or less in ice concentration (vs. 90% in 2005), 94–114 cm in ice thickness (vs. 150 cm in 2005). No snow cover was observed on the ice south of 78° N and 8–10 cm mean snow depth due to new snowfall events, which melted away after 17 August (vs. no snow cover south of 84.3° N or ~10 cm snow depth further north in 2005). Those changes indicate the continuation of ice thinning, less concentration, and younger ice after the 2007 shift, when a record minimum sea ice extent was observed. Overall, the measurements provided a valuable dataset of sea ice morphological properties over the Arctic Pacific Sector in summer 2010, which confirms, by comparison with previous data, that a "new normal" of Arctic sea ice is now present and is a benchmark for measurements of possible future changes.