bluuebunny/crossref_metadata_2025 huggingface dataset:
The shadow of the Falling Man as an end of (im)mediate trauma
Authors: Stegmaier Sanna
Published: August 2013

Douze ans après le 11 septembre, il faut faire la distinction entre ce que l’on appelle « les romans du 11 septembre » (« 9/11 novels ») et « les romans post-11 septembre » (« Post-9/11 novels »). Basé sur les romans Extremely Loud and Incredibly Close (2005) de Jonathan Safran Foer et The Zero (2006) de Jess Walter, cet essai décrit le passage d’une reproduction compulsive à une intégration de l’événement traumatique au sein du roman américain du xxie siècle. En se référant à la théorie du traumatisme et à la crise essentielle des médias après le 11 septembre, la représentation (ou son absence) de Ground Zero comme un espace blanc dans la mémoire culturelle devient un facteur de différenciation pour les romans.
The Art of Watching. The literary Motif of the Window and its Potential for Metafiction in contemporary Literature
Authors: Zocco Gianna
Published: August 2013

Depuis le romantisme, les écrivains utilisent fréquemment le motif de la fenêtre pour discuter des questions métafictionnelles. Alors que certains textes, comme Des Vetters Eckfenster (1822) d’ E.T.A. Hoffmann, décrivent le regard masculin sur la femme afin de construire le modèle d’un auteur supérieur et confiant, des romans contemporains, comme Die Wiederholung (1986) de Peter Handke ou The Enchantment of Lily Dahl (1996) de Siri Hustvedt, sont influencés par la déconstruction de la figure traditionnelle de l’auteur dans le contexte des théories du subjectivisme, du post-structuralisme et des études de genre. Néanmoins, ces textes font tous un large usage du motif de la fenêtre afin de traiter de questions métafictionnelles. Envisageant le motif de la fenêtre comme une “mise en reflet” dont le potentiel métafictionnel est lié à la ressemblance entre « l’art de regarder » et l’art d’écrire et de lire, cet article propose deux couples de paramètres, objectivité/subjectivité et mimesis/poiesis, pour classifier les différents scénarios métafictionnels liés au motif de la fenêtre dans la littérature contemporaine.
Collaborative Writing in Composition
Authors: Friend Christopher R.
Published: August 2013

As online education grows in popularity, the literature on such courses has expanded as dramatically. However, discussion of online tools specifically for composition instruction has received far less attention than general course-management systems and online discussion forums. The composition process has changed with the advent of computer processing, yet composition research rarely focuses on the advantages of the digital composition process. That process could change again with recent developments in social systems and networked, cloud-based applications. This article highlights the way online composition platforms can meet the needs of writing courses. New tools can provide new opportunities for student collaboration, teacher involvement, and writing-process research. This article uses Sally J. McMillan’s model of Cyber-Interactivity and Robert R. Johnson’s model of User-Centered Design as frameworks in which to view collaborative writing, arguing that students in online composition courses need collaborative tools that allow a single document to be created by a student, edited by others, and commented on by all. The ill-fated Google Wave platform is evaluated through this perspective. Practical benefits of the platform and implications for writing instruction are included. Collaborative online composition, using systems with features like Google Wave, is presented as essential in modern composition courses.
Integrating Blended Learning into Situational Writing for Vocational High School Students
Authors: Yen Hsiu-Ling , Lou Shi-Jer , Shih Ru-Chu
Published: August 2013

This study aims to explore vocational high school students’ attitudes toward integrating blended learning into situational writing, and the learning effectiveness of that integration. A total of 84 vocational high students were divided into an experimental group and a control group. The experimental group received writing instruction through an online platform, whereas the control group received writing instruction in traditional classrooms. Attitude toward writing and writing performance were assessed before and after the experiment. Also, learning satisfaction survey was conducted afterwards. The findings of this study reveal that results of the post-test total scores and behavior are significantly higher than the pre-test total scores and behavior results for both the experimental and control groups. Particularly, organization, language usage, and the overall performance in the students’ writings are significantly improved. Scores for affection and behavior and total scores for attitude toward writing are significantly higher for the experimental group than for the control group. Both groups show significant satisfaction with the instructional method, interactivity, and total grades.
The Effects of 3D Animated Movies and Interactive Applications on the Development of Visual Perception in 60-72-Months-Old Children
Authors: Yücelyiğit Seçil , Aral Neriman
Published: August 2013

This study investigated whether the visual perception of 60- to 72-month-old kindergarteners attending a special program that included three-dimensional (3D) (stereoscopic) animated movies and interactive applications differed from that of children who attended only preschool. The sample included 62 children. Thirty received a training program including 3D animated movies and interactive applications every month for 5 months; for comparison, 32 did not engage in any special programs. Mann–Whitney U and Kruskal–Wallis tests were used to analyze the data. The results show that, on average, the visual perception of children who attended the training program was significantly better than that of children who did not.
Capacity and Service (CapServ) Adaptive Trust Computation by Territory Formation in Ubiquitous Environment
Authors: Adithya B. , Babu B. Sathish
Published: August 2013

Ubiquitous computing has been studied extensively as a post desktop model. Secure communication among various heterogeneous networks is been a challenge in service environment with location dynamism of the nodes. In this paper the authors proposed model for trust worthy communications among devices of various networks in a ubiquitous environment with varied service needs, security needs and computational-storage capacities. The model uses a novel approach for computing trust - adaptive to capacity and services.
Design of Context Aware Recommendation Engine for Cell Phone using Bayesian Network, Fuzzy Logic, and Rough Set Theory
Authors: Thyagaraju G. S.  , Kulkarni U. P.
Published: August 2013

In this paper the authors have presented design and implementation of context aware service recommendation engine for cell phone. Context aware service recommendation engine for mobile is designed to automatically adopt its behavior to changing environment. To achieve this, an important issue to be addressed is how to effectively select services for adaptation according to the user’s current context. In this paper, the authors propose an intelligent service recommendation model. They formulate the service adaptation process by using artificial intelligence techniques like Bayesian Network, fuzzy logic and rough sets based decision table. Bayesian Network to classify the incoming call (high priority call, low priority call and unknown calls), fuzzy linguistic variables and membership degrees to define the context situations, the decision rules for adopting the policies of implementing a service.
Mining Data Streams with Skewed Distribution based on Ensemble Method
Authors: Wang Yi
Published: August 2013

In recent years, there have been some interesting studies on predictive modeling in data streams. However, most such studies assume relatively balanced and stable data streams but cannot handle well skewed (e.g., few positives but lots of negatives) and skewed distributions, which are typical in many data stream applications. In this paper, we propose an ensemble and cluster based sample method to deal with this situation. The study shows that this method has effective result on skewed data streams mining.
SVM Parameter Optimization based on Immune Memory Clone Strategy and Application in Bus Passenger Flow Counting
Authors: Fang Zhu , Junfang Wei
Published: August 2013

The performance of support vector mchine (SVM) depends on the selection of model parameters, however, the selection of SVM model parameters more depends on the empirical value. According to the above deficiency, this paper proposed a parameters optimization method of support vector machine based on immune memory clone strategy (IMC). This method can solve the multi-peak model parameters selection problem better which is introduced by n-folded cross-verification. Tests on standard datasets show that this method has higher precision and faster optimization speed compared with other four methods. Then the proposed method was applied to bus passenger flow counting. The experimental results show that the method reposed in this paper obtains higher classification accuracy.
Dynamic Document Clustering Using Singular Value Decomposition
Authors: Nadubeediramesh Rashmi , Gangopadhyay Aryya
Published: August 2013

Incremental document clustering is important in many applications, but particularly so in healthcare contexts where text data is found in abundance, ranging from published research in journals to day-to-day healthcare data such as discharge summaries and nursing notes. In such dynamic environments new documents are constantly added to the set of documents that have been used in the initial cluster formation. Hence it is important to be able to incrementally update the clusters at a low computational cost as new documents are added. In this paper the authors describe a novel, low cost approach for incremental document clustering. Their method is based on conducting singular value decomposition (SVD) incrementally. They dynamically fold in new documents into the existing term-document space and dynamically assign these new documents into pre-defined clusters based on intra-cluster similarity. This saves the cost of re-computing SVD on the entire document set every time updates occur. The authors also provide a way to retrieve documents based on different window sizes with high scalability and good clustering accuracy. They have tested their proposed method experimentally with 960 medical abstracts retrieved from the PubMed medical library. The authors’ incremental method is compared with the default situation where complete re-computation of SVD is done when new documents are added to the initial set of documents. The results show minor decreases in the quality of the cluster formation but much larger gains in computational throughput.
The Simulation-Game Controversy
Authors: Parker J. R. , Becker Katrin
Published: August 2013

Games use the same base technology and design strategy as do simulations, but add a few items to the mixture. Understanding this gives ‘new’ (read borrowed) tools for game creation and testing. The idea that simulations are implementations of a model, for instance, leads to a focus on the model rather than the code when designing a game. Similarly, the verification/validation pair used in simulations can be extended by adding playtesting for games, thus giving an educational game (for example) viable, demonstrable educational characteristics as well as playable (and thus engaging and motivating) characteristics. Productive work on improving games for specific purposes (serious games) can be advanced if the authors can agree on a common terminology and concept set (Shaw & Gaines, 1989), and if games can be seen as a valuable extension of a simulation that has specific characteristics that make them useful in specific circumstances. The idea of ‘fun’ is often thought of as the enemy of ‘learning’ in educational literature, and this needs to change if progress on serious and educational games is to be made. This paper will describe the hierarchy of computer simulation objects within which ludic simulations can be understood.
From Fiction to Reality and Back
Authors: Mosca Ivan
Published: August 2013

The relation between games and simulations can be profitably investigated by combining ontological tools and recent neurological findings. Neurology shows that simulations are connected to fiction or to reality by a suspension of disbelief or alternatively a suspension of belief, and ontological categories of Mimesis (simulation of an event or an object) and Catharsis (simulation of the experience of an event or object) lead to a classification of ludic simulations, which allow to discover some of their hidden properties. This paper raises some new issues for the field, like Embodied Simulation, Simulations of Depth and of Surface, the Ontological and the Epistemological Barrier, the Simulation Story, and the K-Rule. Finally, some wittgensteinian tools (semantic, syntactic, infra-semantic, and super-syntactic) are used in order to suggest how to transform a simulation into a ludic simulation.
An Experimental Evaluation of the Effectiveness of Endogenous and Exogenous Fantasy in Computer-Based Simulation Training
Authors: Mancuso Vincent F. , Hamilton Katherine , Tesler Rachel , Mohammed Susan , McNeese Michael
Published: August 2013

The increased use of simulations in training and education has heightened the need among researchers and practitioners to better understand how simulations impact learning. Given the dearth of empirical research in this area, the purpose of this study was to test the effect of fantasy, one of the most popular attributes of simulations, on multiple outcomes of learning. Data were collected using an experimental design in which the type of fantasy was manipulated (endogenous, exogenous, and no fantasy). Participants included 60 undergraduate teams performing an emergency crisis management simulation. The results of the study showed that fantasy, regardless of type, was a significant predictor of affective learning outcomes. On the other hand, fantasy did not significantly predict behavioral learning outcomes. The authors discuss the implications of these findings for the design and implementation of ludic simulations as well as recommendations for future research.
Using a Ludic Simulation to Make Learning of Middle School Space Science Fun
Authors: Liu M. , Horton L. , Kang J. , Kimmons R. , Lee J.
Published: August 2013

In this paper, the authors describe a ludic simulation designed for middle school space science and examine its use to support students’ learning and motivation. The participants were 383 sixth graders and 447 seventh graders. The findings of this study showed that sixth- and seventh-graders perceived the simulation as having substantial ludic characteristics and educational value. The results indicated that having a playful experience is important for this age group and that participating in a ludic simulation can help motivate students to learn school subjects. Results also indicated that incorporating ludus into the learning experience can improve students’ attitudes toward the subject matter. Implications of policy, research, and practice with regard to using ludic simulations to support classroom-based learning were discussed.
Ludic Learning
Authors: Hayes Aleshia T. , Straub Carrie L. , Dieker Lisa A. , Hughes Charlie E. , Hynes Michael C.
Published: August 2013

New and emerging technology in the field of virtual environments has permitted a certain malleability of learning milieus. These emerging environments allow learning and transfer through interactions that have been intentionally designed to be pleasurable experiences. TLE TeachLivE™ is just such an emerging environment that engages teachers in practice on pedagogical and content aspects of teaching in a simulator. The sense of presence, engagement, and ludus of TLE TeachLivE™ are derived from the compelling Mixed Reality that includes components of off-the shelf and emerging technologies. Some of the noted features that have been identified relevant to the ludic nature of TeachLivE include the flow, fidelity, unpredicability, suspension of disbelief, social presence, and gamelike elements. This article explores TLE TeachLivE™ in terms of the ludology, paideic user experience, the source of the ludus, and outcomes of the ludic nature of the experience.
Digital Play
Authors: McLeod Julie K. , Dondlinger Mary Jo , Vasinda Sheri , Haas Leslie
Published: August 2013

This article reports on Digital Play, one of three prominent themes identified in a qualitative case study of sixth grade students who used mathematical simulations in their proportional thinking unit of study. The study was designed to investigate learner curiosity but found play as a prominent theme. Five different virtual manipulatives or simulations were used as part of the study. The Digital Play theme is then further examined, identifying aspects of the virtual manipulatives that led to play and ludic activities. Students’ interview responses revealed all three of Salen and Zimmerman (2004) categories of play, which also align with several patterns of play identified by the National Institute for Play (2009), during their use of the simulations. Students also described the nature of their play with the simulations which was traced to Winnicott’s (2007) potential space. Finally, the implication of the possibility for transformative play is discussed.
Characterizing User Behavior in a European Academic WiFi Network
Authors: Zola Enrica , Barcelo-Arroyo Francisco
Published: August 2013

Wireless local area networks (WLANs) are commonplace in many universities. Understanding the trends in the usage of these networks is becoming more important. Interesting results can be extracted about association patterns by analyzing WLAN traces from real scenarios. In this work, the library in the main campus of the Technical University of Catalonia (UPC) in Barcelona has been studied. Daily and weekly patterns of the WLAN connections are shown. The population accessing the network is mostly composed of infrequent users: half of the population accesses the WLAN once during each month. Many users associate to only one of the twelve possible access points, which means that, despite the widespread use of lightweight devices, many users are static. The results of this analysis provide general tools for characterizing campus-wide WLAN and a better understanding of usage and performance issues in a mature wireless network.
One Stage Implant-Based Reconstruction of the Breast in a Single Patient: Comparison between Mesh and Modified Dual Plane Technique
Authors: Riggio Egidio , Ottolenghi Joseph , Grassi Veronica , Nava Maurizio
Published: August 2013

Acellular dermal matrix and similar meshes are used in breast reconstruction to cover the inferior implant pocket. We considered whether using a modified dual-plane technique in immediate breast reconstruction could improve the outcome when compared with mesh reconstruction. The paper presents a case of a patient who underwent one-stage bilateral immediate breast reconstruction (IBR) with 470 g implants, using alloplastic mesh in one side and the composed dual-plane pocket in the other. In the case described, the composed dual plane technique gave a better result in terms of absence of rippling and smoother surface at the palpation; the mesh coverage gave a better inframammary contour. Our case suggests that the modified dual-plane technique gives a satisfactory cosmetic outcome. It also reduces costs and avoids mesh-related complications. This technique should therefore be considered as an option to the mesh in implant-based breast reconstruction.
Quantifying photosynthetic rates of microphytobenthos using the triple isotope composition of dissolved oxygen
Authors: Stanley Rachel H. R. , Howard Evan M.
Published: August 2013

Microphytobenthos are important mediators of nutrient and carbon fluxes in coastal environments. However, quantifying production rates by microphytobenthos is difficult, and existing methods necessitate perhaps erroneous assumptions that dark respiration equals light respiration. Here we present a new method for quantifying photosynthetic rates of microphytobenthos, i.e., gross primary production, by using the triple isotope composition of dissolved oxygen in benthic flux chambers. Because the triple oxygen isotope signature is sensitive to photosynthesis, but not to respiration, this method allows quantification of gross photosynthetic oxygen fluxes by microphytobenthos without assumptions about respiration. We present results from field experiments in Waquoit Bay, Massachusetts, that illustrate the method.
Photoacoustics: a novel application to the determination of photosynthetic efficiency in zooxanthellate hermatypes
Authors: Pinchasov‐Grinblat Yulia , Mauzerall David , Goffredo Stefano , Falini Giuseppe , Dubinsky Zvy
Published: August 2013

We present here a novel application of photoacoustics to the monitoring and study of the physiological status of zooxanthellate corals. Until now, the method has only been applied in homogeneous phytoplankton cultures and field samples. Corals are among the world's most productive ecosystems because they host symbiotic dinoflagellates (zooxanthellae) that provide them with a large amount of photosynthates for their energy requirements. Coral reefs face unprecedented pressures on local, regional, and global scales due to climate change and anthropogenic disturbances. Responses to such stress are often a decrease in the photosynthetic efficiency of the symbiotic dinoflagellates, as well as bleaching, which involves the mass expulsion of these symbionts or loss of their pigments. Photosynthesis is a sensitive indicator of stress in plants and plays a central role in the nutrition of symbiotic invertebrates. Our aim was to examine the applicability of photoacoustics, developed by us for ecological work with phytoplankton, to the study of symbiotic dinoflagellates in situ. We have determined areal chlorophyll content and light energy storage efficiency with three zooxanthellate coelenterates, two corals and one hydrozoan, hosting symbiotic algae. We also present the effect of temperature elevation on the decrease in photosynthetic efficiency of the symbiotic coral Stylophora pistillata determined by photoacoustics. Our results demonstrate the potential, power, and convenience of photoacoustics in following bleaching‐related changes in coral pigmentation, in the photosynthetic energy storage efficiency of corals, and in its usefulness in diagnosing its health in relation to environmental factors, in the example presented here, seawater warming.
Reliability of rapid, semi‐automated assessment of plankton abundance, biomass, and growth rate estimates: Coulter Counter versus light microscope measurements
Authors: Kim Hyewon , Menden‐Deuer Susanne
Published: August 2013

Here we determined (1) how accurately the semi‐automated Coulter Counter (CC) measured the abundance, volume, and growth rates of mono‐specific plankton cultures compared to light microscopy and (2) whether CC‐derived particle size‐abundance spectra of whole water samples provided a near‐real time assessment of plankton community composition. A significant, positive relationship was found between CC particle and microscope cell abundance and volume estimates for 16 phylogenetically diverse plankton species. However, abundance estimates of the 2 methods differed significantly from a 1:1 relationship, with CC counts on average 15% greater than microscopy counts. Growth rate estimates showed excellent agreement for both methods for all species and were consistent over time. No significant differences in abundance, growth rate, or size estimates were observed due to light levels (Scrippsiella trochoidea) or strain variation (Heterosigma akashiwo). CC‐based, ship‐board characterization of whole plankton communities, from Georges Bank, captured changes in size‐abundance spectra and thus provided a coarse picture of in‐situ community composition. In the laboratory, the CC appears particularly well‐suited to measuring relative changes in cell abundance, such as for growth and grazing rate measurements of mono‐specific laboratory cultures, or when predator and prey species are well separated by size differences. Although microscopy remains essential for plankton analyses, these results suggest that the CC can increase sample size, improving accuracy, and precision of studies requiring frequent sampling or high degrees of replication. Deployment of these automated techniques in the field may aid in quantifying spatial and temporal variability in plankton community structure by forthcoming ocean‐observing systems.
Absorptivity of brown carbon in fresh and photo-chemically aged biomass-burning emissions
Authors: Saleh R. , Hennigan C. J. , McMeeking G. R. , Chuang W. K. , Robinson E. S. , Coe H. , Donahue N. M. , Robinson A. L.
Published: August 2013

Abstract. Experiments were conducted to investigate light absorption of organic aerosol (OA) in fresh and photo-chemically aged biomass-burning emissions. The experiments considered residential hardwood fuel (oak) and fuels commonly consumed in wild-land and prescribed fires in the United States (pocosin pine and gallberry). Photo-chemical aging was performed in an environmental chamber. We constrained the effective light-absorption properties of the OA using conservative limiting assumptions, and found that both primary organic aerosol (POA) in the fresh emissions and secondary organic aerosol (SOA) produced by photo-chemical aging contain brown carbon, and absorb light to a significant extent. This work presents the first direct evidence that SOA produced in aged biomass-burning emissions is absorptive. For the investigated fuels, SOA is less absorptive than POA in the long visible, but exhibits stronger wavelength-dependence and is more absorptive in the short visible and near-UV. Light absorption by SOA in biomass-burning emissions might be an important contributor to the global radiative forcing budget.
Seasonal changes in Fe species and soluble Fe concentration in the atmosphere in the Northwest Pacific region based on the analysis of aerosols collected in Tsukuba, Japan
Authors: Takahashi Y. , Furukawa T. , Kanai Y. , Uematsu M. , Zheng G. , Marcus M. A.
Published: August 2013

Abstract. Atmospheric iron (Fe) can be a significant source of nutrition for phytoplankton inhabiting remote oceans, which in turn has a large influence on the Earth's climate. The bioavailability of Fe in aerosols depends mainly on the fraction of soluble Fe (= [FeSol]/[FeTotal], where [FeSol] and [FeTotal] are the atmospheric concentrations of soluble and total Fe, respectively). However, the numerous factors affecting the soluble Fe fraction have not been fully understood. In this study, the Fe species, chemical composition, and soluble Fe concentrations in aerosols collected in Tsukuba, Japan were investigated over a year (nine samples from December 2002 to October 2003) to identify the factors affecting the amount of soluble Fe supplied into the ocean. The soluble Fe concentration in aerosols is correlated with those of sulfate and oxalate originated from anthropogenic sources, suggesting that soluble Fe is mainly derived from anthropogenic sources. Moreover, the soluble Fe concentration is also correlated with the enrichment factors of vanadium and nickel emitted by fossil fuel combustion. These results suggest that the degree of Fe dissolution is influenced by the magnitude of anthropogenic activity, such as fossil fuel combustion. X-ray absorption fine structure (XAFS) spectroscopy was performed in order to identify the Fe species in aerosols. Fitting of XAFS spectra coupled with micro X-ray fluorescence analysis (μ-XRF) showed the main Fe species in aerosols in Tsukuba to be illite, ferrihydrite, hornblende, and Fe(III) sulfate. Moreover, the soluble Fe fraction in each sample measured by leaching experiments is closely correlated with the Fe(III) sulfate fraction determined by the XAFS spectrum fitting, suggesting that Fe(III) sulfate is the main soluble Fe in the ocean. Another possible factor that can control the amount of soluble Fe supplied into the ocean is the total Fe(III) concentration in the atmosphere, which was high in spring due to the high mineral dust concentrations during spring in East Asia. However, this factor does not contribute to the amount of soluble Fe to a larger degree than the effect of Fe speciation, or more strictly speaking the presence of Fe(III) sulfate. Therefore, based on these results, the most significant factor influencing the amount of soluble Fe in the North Pacific region is the concentration of anthropogenic Fe species such as Fe(III) sulfate that can be emitted from megacities in Eastern Asia.
Dynamic light absorption of biomass burning organic carbon photochemically aged under natural sunlight
Authors: Zhong M. , Jang M.
Published: August 2013

Abstract. Wood burning aerosol produced under smoldering conditions was photochemically aged with different relative humidity (RH) and NOx conditions using a 104 m3 dual outdoor chamber under natural sunlight. Light absorption of organic carbon (OC) was measured over the course of photooxidation using a UV–visible spectrometer connected to an integrating sphere. At high RH, the color decayed rapidly. NOx slightly prolonged the color of wood smoke, suggesting that NOx promotes the formation of chromophores via secondary processes. Overall, the mass absorption cross-section (integrated between 280 nm and 600 nm) of OC increased by 11–54% (except high RH) in the morning and then gradually decreased by 19–68% in the afternoon. This dynamic change in light absorption of wood burning OC can be explained by two mechanisms: chromophore formation and sunlight bleaching. To investigate the effect of chemical transformation on light absorption, wood smoke particles were characterized using various spectrometers. The intensity of fluorescence, which is mainly related to polycyclic aromatic hydrocarbons (PAHs), rapidly decreased with time indicating the potential bleaching of PAHs. A decline of levoglucosan concentrations evinced the change of POA with time. The aerosol water content measured by Fourier transform infrared spectroscopy showed that wood burning aerosol became less hygroscopic as photooxidation proceeded. A similar trend in light absorption changes has been observed in ambient smoke aerosol originating from the 2012 County Line Wildfire in Florida. We conclude that the biomass burning OC becomes less light absorbing after 8–9 h sunlight exposure compared to fresh wood burning OC.
Estimating the contribution of ion–ion recombination to sub-2 nm cluster concentrations from atmospheric measurements
Authors: Kontkanen J. , Lehtinen K. E. J. , Nieminen T. , Manninen H. E. , Lehtipalo K. , Kerminen V.-M. , Kulmala M.
Published: August 2013

Abstract. The significance of ion–ion recombination for atmospheric new particle formation is not well quantified. Here we present and evaluate a method for determining the size distribution of recombination products from the size distributions of neutral and charged clusters. We applied this method to the data measured in Hyytiälä, Finland, to estimate the contribution of ion–ion recombination to the concentrations of atmospheric clusters in the size range of 0.9–2.1 nm. We observed that the concentration of recombination products was highest in the size classes between 1.5 and 1.9 nm. The median concentrations of recombination products were between 1 and 79 cm−3 in different size classes, which resulted in a small proportion of all neutral clusters, varying between 0.05% and 15%. When examining the whole size range between 0.9 and 2.1 nm, the median fraction of recombination products of all neutral clusters was only 1.5%. Overall, the applied method was concluded to be reasonable, and the results are consistent with the earlier estimates on the contribution of recombination products to atmospheric cluster population in Hyytiälä. Still, in order to determine the size distribution of recombination products more accurately in the future, more precise measurements of the size distribution of sub-2 nm clusters would be needed.
Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea
Authors: Lampadariou N. , Kalogeropoulou V. , Sevastou K. , Keklikoglou K. , Sarrazin J.
Published: August 2013

Abstract. Mud volcanoes are a~special type of cold seeps where life is based on chemoautotrophic processes. They are considered to be extreme environments and are characterized by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO (MEditerranean Deep-sea ECOsystems) cruise (2007) with the remotely operated vehicle (ROV) Victor-6000: Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field); and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field). The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Patterns of nematode diversity, the dominant meiofaunal taxon, varied, displaying both very high or very low species richness and dominance, depending on the microhabitat studied. The periphery of the Lamellibrachia and bivalve shell microhabitats of Napoli exhibited the highest species richness, while the reduced sediments of Amsterdam yielded a species-poor nematode community dominated by two successful species, one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that microhabitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold-seep ecosystems on the meiofaunal communities and nematode assemblages.
Late Cenozoic continuous aridification in the western Qaidam Basin: evidence from sporopollen records
Authors: Miao Y. F. , Fang X. M. , Wu F. L. , Cai M. T. , Song C. H. , Meng Q. Q. , Xu L.
Published: August 2013

Abstract. Cenozoic climate changes in inner Asia provide a basis for understanding linkages between global cooling, the Tibetan Plateau uplift, and possibly the development of the East Asian monsoon. Based on a compilation of palynological results from the western Qaidam Basin, this study reconstructed a 15-million-year (Ma) record of changing vegetation and paleoclimates spanning the middle Miocene to present (comprising two series: ~ 18–5 Ma and ~ 3.1–0 Ma, respectively). The thermophilic percentages were highest between 18 and 14 Ma, and decreased after 14 Ma, closely corresponding to the Middle Miocene Climatic Optimum (MMCO) between 18 and 14 Ma and the following global climatic cooling between 14 and 5 Ma. At the same time, decreases in the xerophytic and coniferous taxa percentages, and the increasing logarithmic ratio of non-arboreal pollen to arboreal pollen (ln (NAP/AP)), reveal the continuous aridification across both the basin and surrounding mountains. Between ~ 3.1 and 0 Ma, the percentages of the thermophilic, xerophytic and coniferous pollen as well as the ln (NAP/AP) imply further cooling and drying in this region since 3.1 Ma. We argue that these vegetation and climate patterns during the late Cenozoic western Qaidam Basin are primarily a result of the global cooling, with the Tibetan Plateau uplift and East Asian summer monsoon having contributions of lesser importance.
A reconstruction of radiocarbon production and total solar irradiance from the Holocene 14C and CO2 records: implications of data and model uncertainties
Authors: Roth R. , Joos F.
Published: August 2013

Abstract. Radiocarbon production, solar activity, total solar irradiance (TSI) and solar-induced climate change are reconstructed for the Holocene (10 to 0 kyr BP), and TSI is predicted for the next centuries. The IntCal09/SHCal04 radiocarbon and ice core CO2 records, reconstructions of the geomagnetic dipole, and instrumental data of solar activity are applied in the Bern3D-LPJ, a fully featured Earth system model of intermediate complexity including a 3-D dynamic ocean, ocean sediments, and a dynamic vegetation model, and in formulations linking radiocarbon production, the solar modulation potential, and TSI. Uncertainties are assessed using Monte Carlo simulations and bounding scenarios. Transient climate simulations span the past 21 thousand years, thereby considering the time lags and uncertainties associated with the last glacial termination. Our carbon-cycle-based modern estimate of radiocarbon production of 1.7 atoms cm−2 s−1 is lower than previously reported for the cosmogenic nuclide production model by Masarik and Beer (2009) and is more in-line with Kovaltsov et al. (2012). In contrast to earlier studies, periods of high solar activity were quite common not only in recent millennia, but throughout the Holocene. Notable deviations compared to earlier reconstructions are also found on decadal to centennial timescales. We show that earlier Holocene reconstructions, not accounting for the interhemispheric gradients in radiocarbon, are biased low. Solar activity is during 28% of the time higher than the modern average (650 MeV), but the absolute values remain weakly constrained due to uncertainties in the normalisation of the solar modulation to instrumental data. A recently published solar activity–TSI relationship yields small changes in Holocene TSI of the order of 1 W m−2 with a Maunder Minimum irradiance reduction of 0.85 ± 0.16 W m−2. Related solar-induced variations in global mean surface air temperature are simulated to be within 0.1 K. Autoregressive modelling suggests a declining trend of solar activity in the 21st century towards average Holocene conditions.
A likelihood perspective on tree-ring standardization: eliminating modern sample bias
Authors: Cecile J. , Pagnutti C. , Anand M.
Published: August 2013

Abstract. It has recently been suggested that non-random sampling and differences in mortality between trees of different growth rates is responsible for a widespread, systematic bias in dendrochronological reconstructions of tree growth known as modern sample bias. This poses a serious challenge for climate reconstruction and the detection of long-term changes in growth. Explicit use of growth models based on regional curve standardization allow us to investigate the effects on growth due to age (the regional curve), year (the standardized chronology or forcing) and a new effect, the productivity of each tree. Including a term for the productivity of each tree accounts for the underlying cause of modern sample bias, allowing for more reliable reconstruction of low-frequency variability in tree growth. This class of models describes a new standardization technique, fixed effects standardization, that contains both classical regional curve standardization and flat detrending. Signal-free standardization accounts for unbalanced experimental design and fits the same growth model as classical least-squares or maximum likelihood regression techniques. As a result, we can use powerful and transparent tools such as R2 and Akaike's Information Criteria to assess the quality of tree ring standardization, allowing for objective decisions between competing techniques. Analyzing 1200 randomly selected published chronologies, we find that regional curve standardization is improved by adding an effect for individual tree productivity in 99% of cases, reflecting widespread differing-contemporaneous-growth rate bias. Furthermore, modern sample bias produced a significant negative bias in estimated tree growth by time in 70.5% of chronologies and a significant positive bias in 29.5% of chronologies. This effect is largely concentrated in the last 300 yr of growth data, posing serious questions about the homogeneity of modern and ancient chronologies using traditional standardization techniques.
Enhanced timing accuracy for Cluster data
Authors: Yearby K. H. , Walker S. N. , Balikhin M. A.
Published: August 2013

Abstract. The standard timing accuracy for the Cluster mission is ±2 ms. However for inter-spacecraft comparisons of waveform data a much higher accuracy is needed – for example a timing error of 1 ms results in a phase error of 65° for a signal at 180 Hz. Most Cluster data are recorded on an onboard solid state recorder and time stamped using an onboard clock which is calibrated to UTC. Until recently, the error of this onboard clock was allowed to increase to the ±2 ms limit before a new calibration was applied. However, the timing error for real time data is estimated to be only ~11 μs, so these data may be used to prepare a time correction dataset which allows the standard timing accuracy to be improved considerably. This paper describes the details of the preparation and validation of this dataset. Two independent source datasets are used: telemetry to ESTRACK ground stations supporting the main operations of the Cluster spacecraft, and the real time telemetry to the NASA DSN stations supporting the Wide-Band Plasma Wave Investigation.
Transport and retention of phosphorus in surface water in an urban slum area
Authors: Nyenje P. M. , Meijer L. M. G. , Foppen J. W. , Kulabako R. , Uhlenbrook S.
Published: August 2013

Abstract. The transport of excessive phosphorus (P) discharged from unsewered informal settlements (slums) due to poor on-site sanitation is largely unknown. Hence, we investigated the processes governing P transport in a 28 km2 slum-dominated catchment in Kampala, Uganda. During high runoff events and a period of base flow, we collected hourly water samples (over 24 h) from a primary channel draining the catchment and from a small size tertiary channel draining one of the contributing slum areas (0.5 km2). Samples were analyzed for orthophosphate (PO4-P), particulate P (PP), total P (TP) and selected hydro-chemical parameters. Channel bed and suspended sediments were collected to determine their sorption potential, geo-available metals and dominant P forms. We found that P inputs in the catchment originated mainly from domestic wastewater as evidenced by high concentrations of Cl (36–144 mg L-1), HCO3 and other cations in the channels. Most P discharged during low flow conditions was particulate implying that much of it was retained in bed sediments. Retained P was mostly bound to Ca and Fe/Al oxides. Hence, we inferred that mineral precipitation and adsorption to Ca-minerals were the dominant P retention processes. Bed sediments were P-saturated and showed a tendency to release P to discharging waters. P released was likely due to Ca-bound P because of the strong correlation between Ca and total P in sediments (r2 = 0.9). High flows exhibited a strong flush of PP and SS implying that part of P retained was frequently flushed out of the catchment by surface erosion and resuspension of bed sediment. Our findings suggest that P accumulated in the channel bed during low flows and then was slowly released into surface water. Hence, it will likely take some time, even with improved wastewater management practices, before P loads to downstream areas can be significantly reduced.
A new-type flexible rock-shed under the impact of rock block: experimental investigation
Authors: Shi S. , Wang M. , Peng X. , Yang Y.
Published: August 2013

Abstract. The main disadvantage of conventional concrete rock-shed is the need for a massive foundation due to the deadweight of the structure. In order to overcome such construction difficulty and to reduce costs, a new concept of flexible rock-shed is proposed in this paper. The flexible rock-shed is made of flexible nets held up by specially designed steel vaulted structure. An 1:1 prototype is manufactured and tested for functional evaluation with impact experiment. It is shown that the structure can stand for an impact energy of about 250 kJ without observable rupture of the flexible nets or cables and can be put into service again with some maintenances on the steel vaulted structure. Expermental data such as local strains, peak loads and impact times are recorded by dynamic strain gauges, load cells and high speed camera for structural analysis and some complementary suggestions of improving and designing are offered with respect to the joints and components.
Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards
Authors: Novara A. , Gristina L. , Guaitoli F. , Santoro A. , Cerdà A.
Published: August 2013

Abstract. When soil nitrate levels are low, plants suffer nitrogen (N) deficiency but when the levels are excessive, soil nitrates can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The research was carried out in the south coast of Sicily (Italy) to evaluate nitrate trends in a vineyard managed both conventionally and using two different cover crops (Triticum durum and Vicia sativa cover crop). A 10 m-wide buffer strip was seeded with Lolium perenne at the bottom of the vineyard. Soil nitrate was measured monthly and nitrate movement was monitored by application of a 15N tracer to a narrow strip between the bottom of vineyard and the buffer and non-buffer strips. Lolium perenne biomass yield in the buffer strips and its isotopic nitrogen content were monitored. Vicia sativa cover crop management contributed with an excess of nitrogen, and the soil management determined the nitrogen content at the buffer areas. A 6 m buffer strip reduced the nitrate by 42% with and by 46% with a 9 m buffer strip. Thanks to catch crops, farmers can manage the N content and its distribution into the soil over the year, can reduced fertilizer wastage and reduce N pollution of surface and groundwater.
Region-wide glacier mass balances over the Pamir-Karakoram-Himalaya during 1999–2011
Authors: Gardelle J. , Berthier E. , Arnaud Y. , Kääb A.
Published: August 2013

Abstract. The recent evolution of Pamir-Karakoram-Himalaya (PKH) glaciers, widely acknowledged as valuable high-altitude as well as mid-latitude climatic indicators, remains poorly known. To estimate the region-wide glacier mass balance for 9 study sites spread from the Pamir to the Hengduan Shan (eastern Himalaya), we compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008–2011) DEMs derived from SPOT5 stereo imagery. During the last decade, the region-wide glacier mass balances were contrasted with moderate mass losses in the eastern and central Himalaya (−0.22 ± 0.12 m w.e. yr−1 to −0.33 ± 0.14 m w.e. yr−1) and larger losses in the western Himalaya (−0.45 ± 0.13 m w.e. yr−1). Recently reported slight mass gain or balanced mass budget of glaciers in the central Karakoram is confirmed for a larger area (+0.10 ± 0.16 m w.e. yr−1) and also observed for glaciers in the western Pamir (+0.14 ± 0.13 m w.e. yr−1). Thus, the "Karakoram anomaly" should be renamed the "Pamir-Karakoram anomaly", at least for the last decade. The overall mass balance of PKH glaciers, −0.14 ± 0.08 m w.e. yr−1, is two to three times less negative than the global average for glaciers distinct from the Greenland and Antarctic ice sheets. Together with recent studies using ICESat and GRACE data, DEM differencing confirms a contrasted pattern of glacier mass change in the PKH during the first decade of the 21st century.