bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing Data Security in E-Markets through Relationship Driven Access Control
Authors: Wang Harry , Zhao J. Leon , Chen Guoqing
Published: March 2012

Data security in e-markets is vital to maintaining trust among trading partners. In an e-market, companies must share information to improve operational efficiency in their supply chains, while at the same time, access to sensitive information by rival companies should be prevented. In today’s highly dynamic business environment, the relationships among companies in e-markets are constantly changing while these relationships determine how company information should be shared with other companies. In this paper, the authors show that existing access control models are not designed for managing data security in e-markets with dynamic company relationships and propose a Relationship Driven Access Control (RDAC) model to provide a better solution. In particular, the authors design a rule-based approach for managing dynamic company relationships and a secure query processing mechanism to filter shared information based on company relationships. A prototype system is developed to demonstrate and validate the authors’ RDAC model.
An Alternative Fit through Problem Representation in Cognitive Fit Theory
Authors: Chan Hock Chuan , Goswami Suparna , Kim Hee-Woong
Published: March 2012

This paper uses cognitive fit theory to analyze the problem solving process in spreadsheet analyses. Cognitive fit theory proposes the formation of mental representation as a part of the problem solving process. However, there is little research examining mental representation, which is a key concept in cognitive fit theory. This study examines the formation of mental representation and proposes an alternative mechanism of cognitive fit between different problem representations and their corresponding mental representations when the task is invariant, but the problem representation changes. Mental representation is then empirically assessed based on the application of Hick’s law, which states that the response time of users making a choice varies with the logarithm of the number of possible choices. Therefore, this study contributes to research on cognitive fit theory by proposing an alternative fit and by demonstrating a feasible approach for identifying mental representations. It contributes to spreadsheet research by showing how problem representations affect task performance in the case of spreadsheet error correction.
Classifying Very High-Dimensional Data with Random Forests Built from Small Subspaces
Authors: Xu Baoxun , Huang Joshua Zhexue , Williams Graham , Wang Qiang , Ye Yunming
Published: March 2012

The selection of feature subspaces for growing decision trees is a key step in building random forest models. However, the common approach using randomly sampling a few features in the subspace is not suitable for high dimensional data consisting of thousands of features, because such data often contains many features which are uninformative to classification, and the random sampling often doesn’t include informative features in the selected subspaces. Consequently, classification performance of the random forest model is significantly affected. In this paper, the authors propose an improved random forest method which uses a novel feature weighting method for subspace selection and therefore enhances classification performance over high-dimensional data. A series of experiments on 9 real life high dimensional datasets demonstrated that using a subspace size of features where M is the total number of features in the dataset, our random forest model significantly outperforms existing random forest models.
E-Collaboration Media Use and Diversity Perceptions
Authors: Thatcher Sherry M. B. , Brown Susan A. , Jenkins Jeffrey L.
Published: March 2012

Virtual organizations enable collaboration and interaction among a diverse set of people regardless of their temporal and spatial dispersion. Throughout the life of a virtual organization, diversity plays an influential role in determining outcomes that ultimately affect the longevity and success of the organization. The goal of this paper is to describe the role diversity plays during different organizational evolutionary approaches, and how e-collaboration media characteristics interact with diversity and organizational evolution to influence outcomes. The authors leverage media synchronicity theory to discuss how the characteristics of different e-collaboration media can reduce or enhance perceived diversity. The role that perceived diversity has in determining outcomes is a function of whether a virtual organization is evolving according to the life-cycle, telelogical, or dialectic evolutionary approaches. Guided by organizational evolution, diversity, attribution, and media theories, the authors propose a theoretical framework with a set of propositions. The authors also provide an illustration of how the framework may be implemented by managers of virtual organizations.
Future Directions of the Conferencing and Collaboration Field
Authors: Keary Alfie , Redfern Sam
Published: March 2012

In this paper, the authors discuss fifteen semi-structured interviews carried out in 2010 with international industry experts and thought leaders within the conferencing and collaboration (C&C) field. The interviews focused on 5, 10, and 15-year time frames, and sought to elicit predictions on the components and services of future C&C platforms, as well as organisational issues such as the likely impacts on business value chains. The authors performed Affinity Diagramming / KJ Analysis in order to assess common themes and impose structure on the information gathered in the interviews. Themes included ease of use, improved presence/social context, formalised social networking capabilities, virtual worlds, remote interactive tools, meta-knowledge / context capture, identity and trust, and key barriers to C&C uptake across organisations. Pre-conditions for maturation of the field include the emergence of interoperability and standards, and the development of corporate education policies.
Public Opinion on YouTube
Authors: Chambers Barbara J. , Bichard Shannon L.
Published: March 2012

From the communication methods to the candidates on the ballot, the 2008 presidential campaign was revolutionary. Communicating party platforms went beyond traditional media to include social media and online video services such as YouTube. These communication methods provide an opportunity to examine public feedback on candidates that ranged widely in age, race, gender, and experience. This study seeks to analyze comments posted on YouTube as a form of public opinion and determine their content and frame of reference in response to vice-presidential nominee Sarah Palin’s acceptance speech at the Republican National Convention. The Functional Theory of Political Discourse is used as a means to reveal prominent framing strategies. Results indicate a majority of YouTube user comments were negative, focused on the present, and utilized the attack function. Character also emerged as a dominant issue in campaign discussion.
Impact of Vendor Selection on Firms’ IT Outsourcing
Authors: Han Jae-Seung , Lee Sang-Yong Tom
Published: March 2012

Information technology (IT) outsourcing is often used as a cost-saving strategy for firms. In IT outsourcing, the choice of vendor is a key factor determining success. This study examines the impact that the choice of IT vendor has on firms’ IT outsourcing in Korea. The authors empirically analyzed the impact of certain characteristics of IT vendors on the market value of client firms in Korea using the event study methodology. First, the authors found that IT outsourcing announcements significantly increased the market value of firms. The authors also found that the market response to high asset-specific services of the IT vendor was significantly greater than the response to low asset-specific services. The authors’ results also showed that the effect of Korean vendors was greater than that of foreign vendors. However, the difference between IT outsourcing to large vendors and small vendors in Korea was not significant, in contrast to the US. The information provided in this study can be used by client firms to select better IT vendors and by IT vendors to develop strategies to survive the rapidly changing IT outsourcing market in Korea.
Pre-Service Teachers’ Perceptions of Information Assurance and Cyber Security
Authors: Agamba Joachim Jack , Keengwe Jared
Published: March 2012

This study was designed to compare pre-service teachers’ attitudes to those of general computer end-users on taking proactive measures to prevent cyber crime. Nineteen pre-service teachers, enrolled in a three-credit technology course in 2009, completed a survey instrument created by the researchers to analyze perceptions of Information Assurance (IA) and cyber security. The findings indicated a lack of best practices in IA that was no different from that of general computer end-users to protect personal electronic information.
Microbursts
Authors: Elwood Susan , Keengwe Jared
Published: March 2012

The authors examine the Microburst Framework and the literature on Cloud and Mobile Computing with a focus on the educators’ thinking processes and the power of the constructivist learning environment interactions. The Microburst Framework is designed to address the increased thinking processes needed in Cloud and Mobile computing, and is based upon other theories and frameworks as described in the article. The purpose of this article is to provide educators of all ages an efficient and effective framework that could be useful in their instructional designs and skill acquisition for Cloud and Mobile Computing learning environments.
Cyber-Dissent and Power
Authors: Bowe Brian J. , Blom Robin , Freedman Eric
Published: March 2012

The expansion of access to information and communication technologies (ICTs) has provided new political organizing tools for citizens — a development of particular importance for individuals living under authoritarian regimes that rely on the repression of free speech to maintain power. Such repressitarian elites exert control over citizen online communications, but it is economically counterproductive for countries hoping to engage in the 21st century’s wired economy to crack down tightly on Internet. This article examines the struggles between maintaining openness and crackdowns in Iran, Egypt, China, and Singapore. These four countries are known to exert severe controls over free expression. However, Iran and Egypt have seen the rise of organized opposition movements despite the controls on media expression, whereas China and Singapore offer useful case studies on the economic dimensions of the balance between participating in the globally networked society and controlling citizen expression.
Faults and Their Relationship to Implemented Patterns, Coupling and Cohesion in Commercial C# Software
Authors: Gatrell Matt , Counsell Steve
Published: March 2012

This paper documents a study of fault proneness in commercial, proprietary software and attempts to determine whether a relationship exists between class faults and the design context of a class, namely the coupling and cohesion of a class, and whether the class is a participant of common design patterns. The authors studied a commercial software system for a 24 month period and identified design pattern participants by inspecting the design documentation and source code; coupling and cohesion metrics were measured by inspecting the source code with a tool; we also extracted fault data for the same period to determine whether a relationship existed between the design context and the fault propensity of a class. Results showed that design pattern participant classes were marginally more fault-prone than non-participant classes, The Adaptor, Method and Singleton patterns were found to be the most fault-prone of thirteen patterns explored. Coupling was found to have a significant relationship with the fault proneness of classes in the system; efferent coupling was a stronger indicator of fault propensity than afferent coupling. Cohesion, when measured using the LCOM(HS) metric, was not found to have a strong relationship with fault proneness.
Focus Group Technique to Study Customer Attitude Towards Online Travel Services in India
Authors: Singh Shveta , Khare Arpita
Published: March 2012

The development of Internet as a service delivery medium has gained ascendancy in recent years. In developing economies, where Internet usage is restricted to an elite few, the potential for e-service delivery channels is being recognized immensely. Online travel services are being accepted as a substitute for travel agents and brick-and-mortar formats. The research explores the attitude and perceptions of Indian customers towards online travel firms. The authors used Focus Group technique, as online travel is still in the embryonic stages and people are aware of its existence but are not familiar with its services. The authors intended to study their feelings and expectations about online travel. This flexibility was possible only through qualitative research technique. The authors considered using the focus-group technique as it is an appropriate technique for generating new ideas within a social context. Financial security of the transactions emerged as one of the strongest determinants of more prolific online behavior with regard to travel.
E-Personalization and Its Tactical and Beneficial Relationships to E-Tailing
Authors: Smith Alan D.
Published: March 2012

The numerous advancements in electronic-personalization communication have generated both benefits and challenges as online retailers try to regain competitive advantages in the current global recession. Through appropriate multivariate analyses and data-reduction techniques, the basic elements e-personalization, namely online purchasing behaviors, personalized communications, information retrieval services, degree of personal web presence, quality assurance of customer service, and the promotion of customization services, were found to be conceptually and statistically related to retailer benefits of e-personalization (increased buying and creates customer loyalty) from the viewpoint of managers for a large goods and services chain store headquartered in Pittsburgh, Pennsylvania.
New Adaptation Linkages
Authors: Nyangosi Richard , Nyariki Kennedy O. , Nyang’au Samuel Nyambega
Published: March 2012

Web technology is transforming all businesses into information-based activities and the rate of technological change is so high that emerging electronic commerce is already making fundamental changes in the economic landscape, affecting every aspect of how business is and will be conducted. There is substantial evidence to suggest that e-banking is being embraced by financial institutions in developed and emerging markets to the extent that explosive growth is almost at hand. This paper explores the adoption linkages in customer perceptions, preferences, and barriers to the adoption of banking technology in Kenya. The data for this study has been collected from bank customers in using well structured and pre-tested questionnaires. The result indicated that necessity perception is positive and ATM, Mobile and Internet banking were mostly preferred compared to others whilst negative linkage was observed between barriers and adoption as Security, bank lag in adoption and unawareness were identified as the most reported barriers to adoption. It means that positive link enable adoption while negative link distract adoption. The findings implicate banks and other financial institutions to increase the campaigns which may develop positive customer perceptions and preferences at the same time look for alternatives of reducing the possible barriers posing the banking technology.
Productivity Evaluation of Self-Adaptive Software Model Driven Architecture
Authors: Magableh Basel , Barrett Stephen
Published: March 2012

Anticipating context changes using a model-based approach requires a formal procedure for analysing and modelling context-dependent functionality and stable description of the architecture which supports dynamic decision-making and architecture evolution. This article demonstrates the capabilities of the context-oriented component-based application-model-driven architecture (COCA-MDA) to support the development of self-adaptive applications; the authors describe a state-of-the-art case study and evaluate the development effort involved in adopting the COCA-MDA in constructing the application. An intensive analysis of the application requirements simplified the process of modelling the application’s behavioural model; therefore, instead of modelling several variation models, the developers modelled an extra-functionality model. COCA-MDA reduces the development effort because it maintains a clear separation of concerns and employs a decomposition mechanism to produce a context-oriented component model which decouples the applications’ core functionality from the context-dependent functionality. Estimating the MDA approach’s productivity can help the software developers select the best MDA-based methodology from the available solutions. Thus, counting the source line of code is not adequate for evaluating the development effort of the MDA-based methodology. Quantifying the maintenance adjustment factor of the new, adapted, and reused code is a better estimate of the development effort of the MDA approaches.
A Unified Approach to Uncertainty-Aware Ubiquitous Localisation of Mobile Users
Authors: Aksenov Petr , Luyten Kris , Coninx Karin
Published: March 2012

Localisation is a standard feature in many mobile applications today, and there are numerous techniques for determining a user’s location both indoors and outdoors. The provided location information is often organised in a format tailored to a particular localisation system’s needs and restrictions, making the use of several systems in one application cumbersome. The presented approach models the details of localisation systems and uses this model to create a unified view on localisation in which special attention is paid to uncertainty coming from different localisation conditions and to its presentation to the user. The work discusses technical considerations, challenges and issues of the approach, and reports on a user study on the acceptance of a mobile application’s behaviour reflecting the approach. The results of the study show the suitability of the approach and reveal users’ preference toward automatic and informed changes they experienced while using the application.
Design and Operation of a Cell Phone-Based Community Hazard Information Sharing System
Authors: Shinohara Mayayuki , Hattori Akira , Ioroi Shigenori , Tanaka Hiroshi , Hayami Haruo , Fujioka Hidekazu , Harada Yuichi
Published: March 2012

This paper presents a hazard/crime incident information sharing system using cell phones. Cell phone penetration is nearly 100% among adults in Japan, and they function as a telecommunication tool as well as a Global Positioning System (GPS) and camera. Open source software (Apache, Postfix, and MySQL) is installed on a system server, and together with the information service provided by Google Maps, are used to satisfy system requirements for the local community. Conventional systems deliver information to all people registered in the same block, even if an incident occurred far from their house. The key feature of the proposed system is that the distribution range of the hazard notification e-mail messages is determined by the geometrical distance from the incident location to the residence of each registered member. The proposed system applies not only to conventional cell phones but also smart phones, which are rapidly becoming popular in Japan. The new system functionality has been confirmed by a trial using members of the local community. System operation began after the successful trial and a training meeting for the local residents. System design, verification results, and operating status are described in this paper.
Relay Selection in Distributed Transmission Based on the Golden Code Using ML and Sphere Decoding in Wireless Networks
Authors: Ge L. , Chen G. J. , Chambers J. A.
Published: March 2012

The implementation of cooperative diversity with relays has advantages over point-to-point multiple-input multiple-output (MIMO) systems, in particular, overcoming correlated paths due to small inter-element spacing. A simple transmitter with one antenna may exploit cooperative diversity or space time coding gain through distributed relays. In this paper, similar distributed transmission is considered with the golden code, and the authors propose a new strategy for relay selection, called the maximum-mean selection policy, for distributed transmission with the full maximum-likelihood (ML) decoding and sphere decoding (SD) based on a wireless relay network. This strategy performs a channel strength tradeoff at every relay node to select the best two relays for transmission. It improves on the established one-sided selection strategy of maximum-minimum policy. Simulation results comparing the bit error rate (BER) based on different detectors and a scheme without relay selection, with the maximum-minimum and maximum-mean selection schemes confirm the performance advantage of relay selection. The proposed strategy yields the best performance of the three methods.
Aiming at the Affective Process of Learning
Authors: Lucas Margarida , Ribeiro Jaime , Moreira António Carrizo
Published: March 2012

Special Education Needs refers to more than just students with learning disabilities that impair their access to and participation in education. Many others struggle each day just to stay in school, focus on lessons or make sense about what is taught. Several students face underachievement and dropout because they feel that school is outdated, uninteresting and does not fulfill their learning needs. In this paper, the authors offer a proposal, often talked about but rarely put into action to bring back struggling students to school: to use multiple forms of presenting information and expression in order to attract students that need more dynamic and broader learning strategies.
Using Moodle Platform Online to Work out on Solving Multiple Options Questions on Microeconomics
Authors: Novo-Corti Isabel , Varela-Candamio Laura , Ramil-Díaz María
Published: March 2012

Along with experience teaching microeconomics, the authors have found that the accuracy of the concepts used and graphic tools, as well as the broad mathematical analytical foundation used by this discipline, draw a stage where some students may feel lost, particularly when they face multiple choice questions. That’s why it’s not unusual to find some people that are not able to get good marks, even when they have a quite good level on microeconomics knowledge. This work deals with an on-line training, based on Moodle platform, to provide students some tools to achieve the best results on their qualifications. The authors used a base data with multiple choice questions on microeconomics to train on solving this kind of questions. The authors presented three different types of questions, based on graphics, on mathematics and on understanding and internalization of microeconomic concepts. Results have shown that this is a practical way to get success in examinations. At the same time, some interesting differences were found on behaviour paths for women, who seem need less time to review the lessons, and men.
Paper Wrapping, Using Connectivity Among Paper Faces
Authors: Watanabe Toyohide , Matsushima Kenta
Published: March 2012

The paper wrapping is one of traditional cultures in Japan, like the paper folding Origami. The technical interest is related to how to decorate goods beautifully along the shapes, and also the requests from daily-life usage are to resolve how to protect goods from external shocks, to carry out materials/goods safely, and so on. Thus, the paper wrapping is intelligent and creative work. This paper addresses a method which can design the target-oriented wrapping procedure successfully and support users’ wrapping works effectively. In order to attain this objective, the authors introduce the knowledge usable in the paper wrapping process and then construct a stage tree to represent various kinds of wrapping means systematically under this knowledge. The authors propose a framework which makes up the paper wrapping process so as to be appropriate to individual target-objects and describe an approach to support the wrapping process visually.
Using Mobile Technology to Bring Families Together
Authors: Jarusriboonchai Pradthana , Väänänen-Vainio-Mattila Kaisa
Published: March 2012

Increased use of digital technology, such as social media or individual entertainment systems, may lead to less face-to-face communication between family members. This paper presents a two-phase design research study on a novel use of technology that could help reconnect co-located family members. The authors present the design qualities for a domestic technology that can increase the level of social interaction within a family. These design qualities provide a guideline for the second phase, in which a novel system concept, FAMEX, is designed to support discussion about family experiences. FAMEX is based on the concept of family history, and involves the creation, finding, and discussion of family memories, which are represented as virtual notes around the home. The design emphasizes ludic values in the form of playful stimulants to face-to-face discussion. Mobile devices, together with augmented reality and embodied interaction, are utilized within the home context: this combination has the potential to raise curiosity and interest, and therefore, encourage ongoing use of the system. In an iterative user study, with prototypes of various fidelities, the participants rejected the features of formal game play, but gave positive feedback to the main features of FAMEX.
VoiceXML for Pervasive Environments
Authors: Radomski Stefan , Schnelle-Walka Dirk
Published: March 2012

The language support of VoiceXML2.1 to express flexible dialogs in pervasive environments is still lacking key features. Missing information about the environment and the inability to react to external events leads to rigid and verbose dialogs. By introducing these features as ECMAScript variables and event handlers in an interpreter, dialog authors can adapt their dialogs’ behavior with regard to the users’ surroundings and incorporate available information from the pervasive environment. Adding these features extends the expressiveness of VoiceXML2.1 and enables the modeling of previously inexpressible, more flexible dialogs.
Warehouse Management System Implementation in a Brazilian Distribution Center
Authors: Scavarda Luiz Felipe , Barros Monica , Scavarda Annibal José , Reyes Pedro M. , Jaska Patrick
Published: March 2012

Information technology, when used appropriately, becomes an important factor for companies searching for logistics excellence. Among the information systems used to support logistics within the supply chain, Warehouse Management System (WMS) has been implemented by many companies that have complex warehousing operations. This article’s goal is to present a WMS implementation process project in a Distribution Center (DC) of a multinational corporation’s subsidiary located in Brazil that deals with home-care products within a high number of varieties. The introduction of the information system itself is not included in this article. Therefore, its current logistics operation is mapped and the main expected benefits with the WMS are analyzed. The article offers the main lessons learned with this new information system project.
The impact of theManual of Nearctic Dipteraon phylogenetic dipterology
Authors: Yeates David K. , Wiegmann Brian M.
Published: March 2012

Our knowledge of the phylogenetic relationships of Diptera advanced through the 20th century at an unprecedented rate; the two crowning achievements of the century were Hennig's magnum opus – theHandbuch der Zoologietreatment of the order and Volume 3 of theManual of Nearctic Dipteraseries, edited by McAlpine and Wood. The Manual is outstanding because of its scope and rigorous, consistent approach, treating the relationships of the entire order at family level using Hennigian argumentation. Synapomorphic characters from all life stages were identified using outgroup comparison and monophyletic taxa were established using synapomorphies mapped onto nodes. The Manual chapters energized a generation of students to publish rigorous, quantitative cladistic phylogenetic treatments of many dipteran groups. The chapters also acted as an authoritative scaffold for the development of dipteran molecular systematics in the 1990s. No other megadiverse insect order has had such an influential phylogenetic springboard into the 21st century.
A review of the crane fly genusEpiphragma(Diptera: Tipulidaes.l.) in North America (including Mexico)
Authors: Gelhaus Jon K. , Ruggeri Anthony
Published: March 2012

This study examines the seven described species ofEpiphragmaOsten Sacken (Diptera: Tipulidaes.l.) known to occur in North America including Mexico. A key to species, descriptions, distributional ranges, habitat information, and literature references are given and the wing patterning and male genitalia are illustrated. The male ofEpiphragma celatorAlexander is described for the first time and the species range is extended north from Michoacan, Mexico to southern Arizona, United States of America. The range ofEpiphragma arizonenseAlexander is extended from southern Arizona south to Sinaloa, Mexico. The male hypopygium ofEpiphragma nebulosum(Bellardi) and wing and hypopygium ofEpiphragmaoreonymphaAlexander are illustrated for the first time.
Steroid-Induced Sigmoid Diverticular Perforation in a Patient with Temporal Arteritis: A Rare Clinical Pathology
Authors: Kaya Bulent , Aras Orhan , Bat Orhan , Bulut Nuriye Esen , Memisoglu Kemal
Published: March 2012

Corticosteroids are used in the treatment of many rheumatological diseases including temporal arteritis. The gastrointestinal perforation during corticosteroid treatment is a serious complication. Colon perforation after steroid use was first reported by Beck et al in 1950. 1 Although the pathophysiological mechanism is not understood clearly, it is claimed that steroids probably by disturbing the intestinal mucosal barrier, facilitate the intestinal perforation. The long term treatment with corticosteroids increases the risk of colon perforation. We are presenting a patient who was taking corticosteroid due to temporal arteritis for two years and operated with sigmoid diverticular perforation.
Current and Emerging Directions in the Treatment of Eating Disorders
Authors: Brown Tiffany A. , Keel Pamela K.
Published: March 2012

Eating disorders are a significant source of psychiatric morbidity in young women and demonstrate high comorbidity with mood, anxiety, and substance use disorders. Thus, clinicians may encounter eating disorders in the context of treating other conditions. This review summarizes the efficacy of current and emerging treatments for anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). Treatment trials were identified using electronic and manual searches and by reviewing abstracts from conference proceedings. Family based therapy has demonstrated superiority for adolescents with AN but no treatment has established superiority for adults. For BN, both 60 mg fluoxetine and cognitive behavioral therapy (CBT) have well-established efficacy. For BED, selective serotonin reuptake inhibitors, CBT, and interpersonal psychotherapy have demonstrated efficacy. Emerging directions for AN include investigation of the antipsychotic olanzapine and several novel psychosocial treatments. Future directions for BN and BED include increasing CBT disseminability, targeting affect regulation, and individualized stepped-care approaches.
OH clock determination by proton transfer reaction mass spectrometry at an environmental chamber
Authors: Barmet P. , Dommen J. , DeCarlo P. F. , Tritscher T. , Praplan A. P. , Platt S. M. , Prévôt A. S. H. , Donahue N. M. , Baltensperger U.
Published: March 2012

Abstract. The hydroxyl free radical (OH) is the major oxidizing species in the lower atmosphere. Measuring the OH concentration is generally difficult and involves elaborate, expensive, custom-made experimental setups. Thus other more economical techniques, capable of determining OH concentrations at environmental chambers, would be valuable. This work is based on an indirect method of OH concentration measurement, by monitoring an appropriate OH tracer by proton transfer reaction mass spectrometry (PTR-MS). 3-pentanol, 3-pentanone and pinonaldehyde (PA) were used as OH tracers in α-pinene (AP) secondary organic aerosol (SOA) aging studies. In addition we tested butanol-d9 as a potential "universal" OH tracer and determined its reaction rate constant with OH: kbutanol-d9 = 3.4(±0.88) × 10−12 cm3 molecule−1 s−1. In order to make the chamber studies more comparable among each other as well as to atmospheric measurements we suggest the use of a chemical (time) dimension: the OH clock, which corresponds to the integrated OH concentration over time.
Chlorophyll fluorescence remote sensing from space in scattering atmospheres: implications for its retrieval and interferences with atmospheric CO2 retrievals
Authors: Frankenberg C. , O'Dell C. , Guanter L. , McDuffie J.
Published: March 2012

Abstract. With the advent of dedicated greenhouse-gas space-borne spectrometers sporting high resolution spectra in the O2 A-band spectral region (755–774 nm), the retrieval of chlorophyll fluorescence has become feasible on a global scale. If unaccounted for, however, fluorescence can indirectly perturb the greenhouse gas retrievals as it perturbs the oxygen absorption features. As atmospheric CO2 measurements are used to invert net fluxes at the land-atmosphere interface, a bias caused by fluorescence can be crucial as it will spatially correlate with the fluxes to be inverted. Avoiding a bias and retrieving fluorescence accurately will provide additional constraints on both the net and gross fluxes in the global carbon cycle. We show that chlorophyll fluorescence, if neglected, systematically interferes with full-physics multi-band XCO2 retrievals using the O2 A-band. Systematic biases in XCO2 can amount to +1 ppm if fluorescence constitutes 1% to the continuum level radiance. We show that this bias can be largely eliminated by simultaneously fitting fluorescence in a full-physics based retrieval. If fluorescence is the primary target, a dedicated but very simple retrieval based purely on Fraunhofer lines is shown to be more accurate and very robust even in the presence of large scattering optical depths. We find that about 80% of the surface fluorescence is retained at the top-of-atmosphere even for cloud optical thicknesses around 2–5. We further show that small instrument modifications to future O2 A-band spectrometer spectral ranges can result in largely reduced random errors in chlorophyll fluorescence, paving the way towards a more dedicated instrument exploiting solar absorption features only.
A synthesis of carbon in international trade
Authors: Peters G. P. , Davis S. J. , Andrew R. M.
Published: March 2012

Abstract. In a globalised world, the transfer of carbon between regions, either physically or embodied in production, represents a substantial fraction of global carbon emissions. The resulting emission transfers are important for balancing regional carbon budgets and for understanding the drivers of regional emissions. In this paper we synthesise current understanding in two parts: (1) embodied CO2 emissions from the production of goods and services produced in one country but consumed in others, (2) physical carbon flows in fossil fuels, petroleum-derived products, harvested wood products, crops, and livestock. We describe the key differences between studies and provide a consistent set of estimates using the same definitions, modelling framework, and consistent data. We find the largest trade flows of carbon in international trade in 2004 were fossil fuels (2673 MtC, 37% of global emissions), CO2 embodied in traded goods and services (1661 MtC, 22% of global emissions), livestock (651 MtC, 20% of total livestock carbon), crops (522 MtC, 31% of total harvested crop carbon), petroleum-based products (183 MtC, 50% of their total production), and harvested wood products (149 MtC, 40% of total roundwood extraction). We find that for embodied CO2 emissions estimates from independent studies are robust. We found that differences between individual studies is not representative of the uncertainty in consumption-based estimates as different studies use different production-based emission estimates as input and different definitions of allocating emissions to international trade. After adjusting for these issues, results across independent studies converge to give less uncertainty than previously assumed. For physical carbon flows there are relatively few studies to be synthesised, but differences between existing studies are due to the method of allocating to international trade with some studies using "apparent consumption" as opposed to "final consumption" in more comprehensive approaches. While results across studies are robust to be used in further applications, more research is needed to understand the differences between methods and to harmonise definitions for particular applications.
A seesaw in Mediterranean precipitation during the Roman Period linked to millennial-scale changes in the North Atlantic
Authors: Dermody B. J. , de Boer H. J. , Bierkens M. F. P. , Weber S. L. , Wassen M. J. , Dekker S. C.
Published: March 2012

Abstract. We present a reconstruction of the change in climatic humidity around the Mediterranean between 3000–1000 yr BP. Using a range of proxy archives and model simulations we demonstrate that climate during this period was typified by a millennial-scale seesaw in climatic humidity between Spain and Israel on one side and the Central Mediterranean and Turkey on the other, similar to precipitation anomalies associated with the East Atlantic/West Russia pattern in current climate. We find that changes in the position and intensity of the jet stream indicated by our analysis correlate with millennial changes in North Atlantic sea surface temperature. A model simulation indicates the proxies of climatic humidity used in our analysis were unlikely to be influenced by climatic aridification caused by deforestation during the Roman Period. That finding is supported by an analysis of the distribution of archaeological sites in the Eastern Mediterranean which exhibits no evidence that human habitation distribution changed since ancient times as a result of climatic aridification. Therefore we conclude that changes in climatic humidity over the Mediterranean during the Roman Period were primarily caused by a modification of the jet stream linked to sea surface temperature change in the North Atlantic. Based on our findings, we propose that ocean-atmosphere coupling may have contributed to regulating Atlantic Meridional Overturning Circulation intensity during the period of analysis.
Development and evaluation of a building energy model integrated in the TEB scheme
Authors: Bueno B. , Pigeon G. , Norford L. K. , Zibouche K. , Marchadier C.
Published: March 2012

Abstract. The use of air-conditioning systems is expected to increase as a consequence of global-scale and urban-scale climate warming. In order to represent future scenarios of urban climate and building energy consumption, the Town Energy Balance (TEB) scheme must be improved. This paper presents a new building energy model (BEM) that has been integrated in the TEB scheme. BEM-TEB makes it possible to represent the energy effects of buildings and building systems on the urban climate and to estimate the building energy consumption at city scale (~10 km) with a resolution of a neighbourhood (~100 m). The physical and geometric definition of buildings in BEM has been intentionally kept as simple as possible, while maintaining the required features of a comprehensive building energy model. The model considers a single thermal zone, where the thermal inertia of building materials associated with multiple levels is represented by a generic thermal mass. The model accounts for heat gains due to transmitted solar radiation, heat conduction through the enclosure, infiltration, ventilation, and internal heat gains. BEM allows for previously unavailable sophistication in the modelling of air-conditioning systems. It accounts for the dependence of the system capacity and efficiency on indoor and outdoor air temperatures and solves the dehumidification of the air passing through the system. Furthermore, BEM includes specific models for passive systems, such as window shadowing devices and natural ventilation. BEM has satisfactorily passed different evaluation processes, including testing its modelling assumptions, verifying that the chosen equations are solved correctly, and validating the model with field data.
An empirical model for the statistics of sea surface diurnal warming
Authors: Filipiak M. J. , Merchant C. J. , Kettle H. , Le Borgne P.
Published: March 2012

Abstract. A statistical model is derived relating the diurnal variation of sea surface temperature (SST) to the net surface heat flux and surface wind speed from a numerical weather prediction (NWP) model. The model is derived using fluxes and winds from the European Centre for Medium-Range Weather Forecasting (ECMWF) NWP model and SSTs from the Spinning Enhanced Visible and Infrared Imager (SEVIRI). In the model, diurnal warming has a linear dependence on the net surface heat flux integrated since (approximately) dawn and an inverse quadratic dependence on the maximum of the surface wind speed in the same period. The model coefficients are found by matching, for a given integrated heat flux, the frequency distributions of the maximum wind speed and the observed warming. Diurnal cooling, where it occurs, is modelled as proportional to the integrated heat flux divided by the heat capacity of the seasonal mixed layer. The model reproduces the statistics (mean, standard deviation, and 95-percentile) of the diurnal variation of SST seen by SEVIRI and reproduces the geographical pattern of mean warming seen by the Advanced Microwave Scanning Radiometer (AMSR-E). We use the functional dependencies in the statistical model to test the behaviour of two physical model of diurnal warming that display contrasting systematic errors.
The Ethical Issues in Human Stem Cell Research: From Principles to Policy
Authors: Zoloth Laurie
Published: March 2012

Human stem cell research, because of its potential for both transformative sources of knowledge and for translation into widespread practical applications, has been a subject of ethical, religious, and policy debates since the first cells were characterized. The technology touches on some of humanities most urgent concerns and some of our most fundamental narratives. Stem cell research is characterized by a swiftly moving knowledge base, with first human embryonic (hES), then induced pluripotent cells (iPS) being seen as the best new hope in the search for cures to diseases. Each new advance in science brings new ethical and moral quandaries to the debate. This presentation will outline the history of ethical questions surrounding stem cell research, describe the variety of responses to such concerns, and define some of the international policy that has emerged to create ethical frameworks for ongoing research on stem cells. We will consider what questions, if any , can be understood as settled within a general consensus, and what questions may be raised by the future directions of stem cell research.
Analysis of Human Endoderm Development Using Lineage-specific Reporter hESCs
Authors: Stanley Ed
Published: March 2012

Human induced pluripotent stem cells (hiPSCs), derived by the in vitro reprogramming of somatic cells, resemble embryonic stem cells (hESCs) derived from the inner cell mass of the pre-implantation blastocyst stage embryo. In vitro, these pluripotent stem cells (PSCs) can be directed to differentiate toward specific lineages and, therefore, represent a tractable platform for the study of important events during the specification of early human cell types. A key step in differentiation is the commitment of PSCs to mesendoderm formation and the subsequent emergence of lineage-restricted progenitors. Studies from both embryology and from in vitro ESC differentiation systems have identified BMP4 and Activin A as important factors that control the direction of differentiation within nascent mesendoderm. Using a completely defined recombinant protein based differentiation medium, we have examined requirements for each of these factors in the generation of a variety of endodermal lineages, including thymus, lung and pancreas. This analysis has been aided by suite of genetically tagged hESC lines that enable precursors representing these cell types to be easily identified.

Human cells generated from differentiated PSCs represent a new tool for medical research as well as an avenue toward potential cell-based therapies of the future. In addition to the cellular products of PSC differentiation, findings from these experiments have interesting parallels with embryology and provide clues to some of the important events surrounding lineage commitment during early human development.