bluuebunny/crossref_metadata_2025 huggingface dataset:
A Spatial Data Model for HIV/AIDS Surveillance and Monitoring in Nigeria
Authors: Idowu Peter Adebayo
Published: May 2012

Sub-Saharan Africa is a region characterised by high rates of several deadly diseases most especially HIV/AIDS. HIV/AIDS alone has claimed the life of many people and turned many innocent children to orphans. There is relatively little consistent or reliable data that can be used for surveillance, monitoring, and management of these diseases in the region HIV/AIDS inclusive. To alleviate the problem of patchy and inconsistent epidemiological data, a well structured, interoperable spatial data model for HIV/AIDS surveillance and monitoring is proposed for Nigeria in this paper. This paper initially reviews some of the existing health data models which were modified and extended to develop a data model for HIV/AIDS surveillance, monitoring, and management. The data model captures information required for the development of HIV/AIDS surveillance systems. The model is developed using the Unified Modelling Language. The work aims to produce the model as an open standard in order to promote collaboration and encourage researchers in developing nations to contribute to the maintenance of the data model. The model is implemented in XML, and will be applied to a system using service oriented architecture.
Parallelized Online Regularized Least-Squares for Adaptive Embedded Systems
Authors: Pahikkala Tapio , Airola Antti , Xu Thomas Canhao , Liljeberg Pasi , Tenhunen Hannu , Salakoski Tapio
Published: May 2012

The authors introduce a machine learning approach based on parallel online regularized least-squares learning algorithm for parallel embedded hardware platforms. The system is suitable for use in real-time adaptive systems. Firstly, the system can learn in online fashion, a property required in real-life applications of embedded machine learning systems. Secondly, to guarantee real-time response in embedded multi-core computer architectures, the learning system is parallelized and able to operate with a limited amount of computational and memory resources. Thirdly, the system can predict several labels simultaneously. The authors evaluate the performance of the algorithm from three different perspectives. The prediction performance is evaluated on a hand-written digit recognition task. The computational speed is measured from 1 thread to 4 threads, in a quad-core platform. As a promising unconventional multi-core architecture, Network-on-Chip platform is studied for the algorithm. The authors construct a NoC consisting of a 4x4 mesh. The machine learning algorithm is implemented in this platform with up to 16 threads. It is shown that the memory consumption and cache efficiency can be considerably improved by optimizing the cache behavior of the system. The authors’ results provide a guideline for designing future embedded multi-core machine learning devices.
Factors Impacting Use of Information Technology by Physicians in Private Practice
Authors: DeMello Jim P. , Deshpande Satish P.
Published: May 2012

This research examines the impact of various factors on the use of IT in clinical practice, prescriptions, and patient information. This was done using a national sample of 3425 physicians who worked in a solo or group practice in the United States. Besides the extent of use of electronic medical records by physicians and number of physicians in practice, none of the other factors consistently impacted the use of IT in clinical practice, prescriptions, and patient information, respectively. The results of this study highlight the need to develop specific strategies to increase the use of information technology in healthcare.
Managing Knowledge Distribution to Prevent Product Imitation and Counterfeiting
Authors: Vladova Gergana , Bahrs Julian , Gronau Norbert
Published: May 2012

Product piracy poses an existential threat to many companies. Juristic property rights, which are currently dominantly discussed, do not suffice to combat this threat. The rise in cases of piracy and increasing professionalism of the counterfeiter, give ground for effective prevention methods. Based on gaps of existing approaches, the authors evaluate how knowledge modeling could design preventive measures. They develop a new approach which makes information and knowledge leaks transparent, analyzable, and controllable. The approach is based on interactions and transfers of information and knowledge between departments of a company with internal and external business partners. For this purpose, a modeling process for knowledge-intensive business interactions is used and modified. Choosing dynamic assessment questions establishes the level of risk of information and knowledge on piracy and prioritizes company specific measures. In addition, the procedure reappraises companies’ existing modes of prevention. Based on this analysis, the method helps to develop and rank measures to hinder the theft of information by pirates. The approach fills the gap in known concepts of protection, which are used only after a case of piracy has taken place. The approach also adds a new perspective in knowledge management.
The Role of Knowledge Sharing in Raising the Task Innovativeness of Systems Analysts
Authors: Reychav Iris , Stein Eric W. , Weisberg Jacob , Glezer Chanan
Published: May 2012

This study examines the relationship between creativity and innovation at the individual level and how knowledge sharing mediates the relationship between these two constructs. A survey was conducted that measured individual creativity, innovativeness, and four types of knowledge sharing: explicit knowledge and tacit knowledge (e.g., experience, know-how, and expertise) sharing. It was postulated that the type of knowledge mediates the relationship between creativity and the innovativeness of task performance among systems analysts. The results show that creativity was positively related to task innovativeness. This relationship was mediated negatively by explicit knowledge sharing but positively mediated by tacit knowledge sharing based on know-how among project team members. These results have implications for system development and implementation projects.
An Investigation of the Impact of Intrinsic Motivation on Organizational Knowledge Sharing
Authors: Welschen Judith , Todorova Nelly , Mills Annette M.
Published: May 2012

Despite heavy investments in knowledge management systems, people are often reluctant to share their knowledge, with knowledge hoarding being one of the largest obstacles to effective knowledge management in organizations. This paper proposes a model that examines the role of intrinsic motivation in knowledge sharing. Bringing together insights from motivational research, Self-Determination Theory and the Theory of Reasoned Action, the study investigates the links between intrinsic motivators and knowledge sharing. Survey data collected from knowledge workers are analyzed using partial least squares. The results show self-efficacy, meaningfulness and impact are important motivators of attitude towards knowledge sharing, which in turn impacts intention to share knowledge. The findings provide insights into employee motivations to share knowledge, and strategies for enhancing knowledge sharing in organizations.
A Hybrid Forecasting Model for Non-Stationary Time Series
Authors: Xiao Yi , Xiao Jin , Wang Shouyang
Published: May 2012

In time series analysis, an important problem is how to extract the information hidden in the non-stationary and noise data and combine it into a model for forecasting. In this paper, the authors propose a TEI@I based hybrid forecasting model. A novel feed forward neural network is developed based on the improved particle swarm optimization with adaptive genetic operator (IPSO-FNN) for forecasting. In the proposed IPSO, inertia weight is dynamically adjusted according to the feedback from particles’ best memories, and acceleration coefficients are controlled by a declining arccosine and an increasing arccosine function. Subsequently, a crossover rate which only depends on generation and an adaptive mutation rate based on individual fitness are designed. The parameters of FNN are optimized by binary and decimal particle swarm optimization. Further, the forecast results of IPSO-FNN are adjusted with the knowledge from text mining and an expert system. The empirical results on the container throughput forecast of Tianjin Port show that forecasts with the proposed method are much better than some other methods.
Fuzzification of EOQ Model Under the Condition of Permissible Delay in Payments
Authors: Jaggi Chandra K. , Sharma Anuj , Jain Reena
Published: May 2012

This paper formulates an economic order quantity inventory model under the condition of permissible delay in payments in fuzzy environment. All the parameters of the model, excluding permissible delay period and cycle length, are taken to be trapezoidal Fuzzy numbers. The arithmetic operations are defined under the function principle. The cost function has been defuzzified using signed distance method and thereby solved to obtain the optimal replenishment period. The numerical example is presented to show the validity of the model followed by sensitivity analysis.
Attribute Decoration of Attack–Defense Trees
Authors: Bagnato Alessandra , Kordy Barbara , Meland Per Håkon , Schweitzer Patrick
Published: May 2012

Attack–defense trees can be used as part of threat and risk analysis for system development and maintenance. They are an extension of attack trees with defense measures. Moreover, tree nodes can be decorated with attributes, such as probability, impact, and penalty, to increase the expressiveness of the model. Attribute values are typically assigned based on cognitive estimations and historically recorded events. This paper presents a practical case study with attack–defense trees. First, the authors create an attack–defense tree for an RFID-based goods management system for a warehouse. Then, they explore how to use a rich set of attributes for attack and defense nodes and assign and aggregate values to obtain condensed information, such as performance indicators or other key security figures. The authors discuss different modeling choices and tradeoffs. The case study led them to define concrete guidelines that can be used by software developers, security analysts, and system owners when performing similar assessments.
Robotics, Ethics, and the Environment
Authors: Borenstein Jason
Published: May 2012

As robots become more pervasive and take on an ever-growing number of tasks, exploring ethical issues relating to the technology takes on increasing importance. Specifically, the manufacturing and sale of personal service robots could be severely detrimental to the environment. Ideally, members of the robotics community would develop a comprehensive awareness of the complex ethical and environmental consequences emerging from their design pathways before historical patterns are repeated.
An Empirical Investigation of External Factors Influencing Mobile Technology Use in Canada
Authors: Kaba Bangaly , Osei-Bryson Kweku-Muata
Published: May 2012

Cell phones have changed the way people live. A deeper understanding of how the attributes of these technologies influence end-users’ perceptions is an important issue. A better understanding of cellular phone adoption and use process will inform people’s understanding of the diffusion process of other types of communication technologies. This empirical paper examines the influence of the Technology Characteristics, Group Characteristics (Familiarity), Mobility, Facilitating Conditions, and Social Influence on the use of the cell phones. Data were collected through a questionnaire survey from a final sample of 277 cell phone users in Quebec (Canada). The results suggest that, among the factors mentioned, only Mobility has a direct influence on the adoption on all the three indicators of use defined in this study. These findings have theoretical and managerial implications, which are highlighted.
Relations Between Social Capital and Use of ICT
Authors: Fuhrer Chantal , Cucchi Alain
Published: May 2012

This article explores the relationship between social capital in a professional network and ICT use. It examines the context in which the main ICT networks are used and shows how they are conditioned by the social capital of an individual within their professional network. To do so, different measures from Social Network Analysis are used. An exploratory study on a group of 199 students is presented. The studied Computer Mediated Communication (CMC) media are electronic mail, telephone, Skype, and Facebook. The results show the important position of an actor in the networks of exchanges. The results also show that ICT uses have different contexts involving different degrees of confidence in the network. Email is shown to be influenced by trust centrality and centrality at work while telephone is more influenced by influence centrality. The authors conclude on the prospects for future research.
Remote Channel Customer Contact Strategies for Complaint Update Messages
Authors: Douglas Gary , Morton Hazel , Jack Mervyn
Published: May 2012

This research focuses on the preservation and repairing of relationships once a banking customer has raised a complaint. This research investigates the impact of different messaging channels (email, Internet banking site messages, SMS text messages, and messages on the ATM screen) and the impact of different styles of complaint update messages on customers’ perceptions of their relationship with their bank. The empirical research is conducted on a sample of 96 banking customers. Quantitative data are collected to examine the impact of the banking channel and the update message style on customers’ perceptions of their relationship with the bank. The results indicate that update messages are a reassurance tool for the bank to use for customers who had cause to raise a complaint. The preferred channels of communication with the customer base for update messages are email and Internet banking. Also, customer-brand relationship was found to be higher for complaint-specific content in the messages than for generic messages.
The Usefulness of Learning Objects in Industry Oriented Learning Environments
Authors: Fernando Shantha , Sol Henk G. , Dahanayake Ajantha
Published: May 2012

A model is presented to evaluate the usefulness of learning objects for industry oriented learning environments that emphasise training university graduates for job opportunities in a competitive industry oriented economy. Knowledge workers of the industry seek continuous professional development to keep their skills and knowledge up to date. Many of the desired features of learning objects and facilities of e-learning systems can be realized in a framework that combines usefulness, usage, and usability. This model on the usefulness of learning objects, called Learning Objects Evaluation Model (LOEM), defines the concepts: academic level specificity, field specificity, industry specificity, operational specificity, and reusability specificity. It also defines an index, called Learning Objects Specificity Index (LOSI) that helps course developers in a course design and development process to assess the usefulness of learning objects.
Learning-by-Doing Teamwork KSA
Authors: Martín-Pérez Víctor , Martín-Cruz Natalia , Pérez-Santana Pilar
Published: May 2012

The objective of this paper is to evaluate the effectiveness of strategic management simulations as a learning-by-doing tool so that university students can learn to work in a team, that is, they can enhance their knowledge, skills, and abilities (KSA) for effective teamwork. The authors have carried out an analysis of the effect of strategic management simulation on the teamwork KSA with a group of undergraduates studying in the School of Business. The results show that teamwork KSA can improve and that the initial knowledge of teamwork KSA, at the individual level, is the only factor which conditions the students’ learning. Initial knowledge of the teamwork KSA and the spread of this knowledge within the team are not a determinant influence on the learning-by-doing of the individual. Neither are features such as intelligence, personality, attitude to teamwork and teamwork self-efficacy, both in terms of the individual as well as the team.
Designing Distance Learning Tasks to Help Maximize Vocabulary Development
Authors: Loucky John Paul
Published: May 2012

Task-based language learning using the benefits of online computer-assisted language learning (CALL) can be effective for rapid vocabulary expansion, especially when target vocabulary has been pre-arranged into bilingual categories under simpler, common Semantic Field Keywords. Results and satisfaction levels for both Chinese English majors and Japanese Engineering majors were high in this qualitative comparative study, indicating its potential for helping many students from various language backgrounds to rapidly expand their target language vocabulary, especially when blended with other real language negotiation tasks, preferably for an authentic audience. Print versus online reading and vocabulary development methods are compared, as well as surveys of both Chinese and Japanese college students, after they were engaged in a “Collaborative Writing Exchange Project” using similar online vocabulary development tools. All target terms were pre-organized and made available under common Semantic Field Keywords online in both Japanese and Chinese, but students had freedom to choose within sets of most relevant words from five academic disciplines. Writing themes were suggested to learners in both countries to keep their email exchanges consistent.
The effect of organisational context on organisational development (OD) interventions
Authors: Brijball Parumasur Sanjana
Published: May 2012

Orientation: Systematic and congruent organisational structures, systems, strategies and designs are necessary for the successful implementation of organisational development (OD) interventions.Research purpose: This article examines national and international OD practices. It assesses the effect of diverse cultures and cultural values for determining the effectiveness of OD interventions.Motivation for the study: Most organisational change and development programmes fail and only a few result in increased competitiveness, improvements and profitability. This emphasises the need for change interventions to give sufficient attention to leadership, cultures, managing change and adopting context-based OD interventions.Research design, approach and method: This article is a literature review of the current trends and research in the area of OD interventions. It synthesises the influence that cultures and cultural orientations have on determining which OD intervention strategies organisations should adopt in different cultures.Main findings: The analysis emphasises how important it is to achieve congruence between the OD interventions organisations select and their local cultures.Practical/managerial implications: It is important to note the evolving nature of the political and economic climates that influence national cultures and that they emphasise that interventions that reflect OD values, which are tailor-made and shaped to the needs of local cultures, are necessary.Contribution/value-add: This study links various OD interventions to Hofstede’s dimensions for differentiating national cultures. It provides guidelines for aligning the practices and techniques of OD to the values and cultures of the organisations and societies in which they are to be implemented.
Recirculación de la sangre durante la sesión de hemodiálisis en el catéter tunelizado PalindromeTM
Authors: Crehuet Rodríguez Isabel , Méndez Briso-Montiano Pilar , Mulero San José Mª Teresa , Bernárdez-Lemus María Albina , Jiménez Maldonado Ángel , Toribio Manrique Beatriz
Published: May 2012

Uno de los problemas más frecuentes que encontramos al utilizar los catéteres venosos tunelizados como acceso vascular para hemodiálisis, es un déficit de flujo sanguíneo, teniendo que invertir las líneas del circuito para poder continuar la sesión. Los investigadores, conscientes de que así puede aumentar la recirculación y derivar en una menor calidad de la técnica, han diseñado un nuevo modelo de catéter, para evitar en lo posible la recirculación de la sangre.
Actualmente, este tipo de catéter es el que se implanta a nuestros pacientes; debido a esto y a la escasez de estudios publicados en estos nuevos catéteres sobre este tema, realizamos un estudio para calcular el porcentaje de recirculación que tienen dichos catéteres, tanto con las líneas del circuito en posición normal como en posición invertida. Calculamos este porcentaje analizando la determinación sérica de la urea, en 4 muestras de sangre, extraídas semanalmente, con las líneas del circuito de hemodiálisis en ambas posiciones y aplicamos la fórmula de recirculación:
R = (BUN A2-BUN A1/BUN A2-BUN V) x 100.
Tras los resultados obtenidos podemos concluir, que el porcentaje de recirculación de la sangre en dichos catéteres es prácticamente el mismo, tanto con las líneas del circuito en una posición como en otra, habiéndose obtenido unas cifras más que aceptables para poder conseguir hemodiálisis de buena calidad, según los parámetros que aconsejan las guías de la sociedad española de nefrología de accesos vasculares.
Receptores de trasplante renal de donantes en asistolia y muerte cerebral: diferencias en los cuidados enfermeros
Authors: García Viana Mª Concepción , Moral Sánchez Silvia , Rodríguez Marcos Raquel , Lope Andrea Teresa , Ridao Cano Natalia
Published: May 2012

Hoy en día es indiscutible que el trasplante renal es el tratamiento sustitutivo de elección para pacientes con enfermedad renal crónica. En nuestro hospital realizamos fundamentalmente dos tipos de trasplante renal, el clásico donante en muerte cerebral y el donante en asistolia. El objetivo de nuestro estudio fue evaluar si existían diferencias en las cargas de trabajo del personal de enfermería dependiendo de un tipo de trasplante u otro.
Se trata de un estudio transversal con 73 pacientes que recibieron un trasplante renal durante el año 2010, 18 procedentes de donante en muerte cerebral y 55 en asistolia. Los trasplante renales de donante en asistolia presentaron mayor incidencia de fallo primario del injerto (15% vs 1,4%) así como mayor retraso de la función renal (18 días vs 0 días). Debido a esto, nuestra labor asistencial se vio incrementada en este tipo de trasplante por precisar un mayor número de biopsias renales que implican unos cuidados de preparación y de vigilancia de sus complicaciones, la necesidad de más sesiones de hemodiálisis y la administración de un mayor número de dosis de timoglobulina. No se objetivaron diferencias significativas en la incidencia de infecciones entre ambos tipo de trasplante, así como en la estancia media hospitalaria, aunque esto último podría estar influido por el tamaño de la muestra.
A pesar de las complicaciones mencionadas, la función renal a medio plazo de ambos tipos de trasplante fue similar, lo que alienta la utilización de los donantes en asistolia.
Relación entre carga laboral y Burnout en enfermeras de unidades de diálisis
Authors: Barrios Araya Silvia , Arechabala Mantuliz Mª Celia , Valenzuela Parada Victoria
Published: May 2012

La hemodiálisis requiere personal de enfermería con altos niveles de capacitación por su complejidad tecnológica, las peculiaridades del tratamiento y la necesidad de tomar decisiones relevantes para la seguridad del paciente en breve espacio de tiempo: Esto condiciona que estos profesionales estén expuestos a múltiples estresores que están directamente relacionados con la aparición de síndrome de Burnout. El objetivo de esta revisión fue conocer la relación entre la sobrecarga laboral y los factores que desencadenan la aparición del síndrome Burnout en el personal de enfermería de las unidades de hemodiálisis. La metodología utilizada fue una búsqueda en bases de datos a través de la colección electrónica del Sistema de Bibliotecas de la Pontificia Universidad Católica de Chile. Cuarenta y tres artículos fueron revisados para analizar los predictores descritos en trabajadores de salud, entre los que destacan: sobrecarga laboral, frecuencia y tiempo dedicado a la atención de pacientes, participación en la toma de decisiones, riesgos laborales y riesgo de afectación psíquica y la incorporación constante de nuevas tecnologías y conocimientos. La evidencia apoya que altos niveles de satisfacción con el puesto de trabajo, relaciones interprofesionales colaborativas, trabajo en equipo, respeto al conocimiento y a la experiencia clínica por parte de los directivos, junto a la posibilidad de participar en la toma de decisiones son factores percibidos por las enfermeras/os como protectores de síndrome de Burnout.
Nickel Corrosion Inhibition in Sulfuric Acid—Electrochemical Studies, Morphologies, and Theoretical Approach
Authors: Amin M.A. , Shokry H. , Mabrouk E.M.
Published: May 2012

The inhibition performance of three selected dihydrazide derivatives, namely, malonic acid (MAD), succinic acid (SAD), and adipic acid (AAD) dihydrazide, was tested in relation to nickel corrosion in 1.0 M sulfuric acid (H2SO4) solution. Electrochemical methods (Tafel polarization, linear polarization resistance [LPR], and electrochemical impedance spectroscopy [EIS]) were used, complemented with scanning electron microscopy/energy-dispersive x-ray (SEM/EDX) examinations. Computational studies were also used to confirm experimental findings and to optimize the adsorption structures of dihydrazide derivatives. Results showed that the three tested dihydrazides inhibited Ni corrosion (mixed-type inhibitors) to an extent, depending on the type and concentration of the introduced inhibitor. SEM studies revealed that the corroded areas on the surface were decreased in the presence of additives to an extent, depending on the type and concentration of the tested inhibitor. Results obtained from electrochemical measurements are in good agreement with theoretical studies.
Effects of Applied Potentials on the Hydrogen-Induced Cracking of Pipeline Steel in Low-Temperature and Low-Dissolved-Oxygen Seawater
Authors: Zhang L. , Du M. , Li Y.
Published: May 2012

The hydrogen-induced cracking of X70 pipeline steel was investigated in low-temperature and low-dissolved-oxygen seawater by means of potentiodynamic polarization, slow strain rate tests (SSRT), and hydrogen permeation measurements. The results showed that the hydrogen evolution potential of X70 steel in low-temperature and low-dissolved-oxygen seawater decreased compared with the normal-temperature seawater. The susceptibility to hydrogen embrittlement increased as the potential shifted in the negative direction. When the polarization potentials were below −1,050 mV vs. saturated calomel electrode (SCE) in low-temperature and low-dissolved-oxygen seawater, the fracture surfaces exhibited quasi-cleavage fracture.
Megacity ozone air quality under four alternative future scenarios
Authors: Butler T. M. , Stock Z. S. , Russo M. R. , Denier van der Gon H. A. C. , Lawrence M. G.
Published: May 2012

Abstract. The impact of the megacities of the world on global tropospheric ozone, and conversely, the extent to which megacities are influenced by emissions of ozone precursors from outside of the megacities is examined under the four alternative RCP ("Representative Concentration Pathway") emissions scenarios. Despite accounting for about 6% of present-day anthropogenic emissions of ozone precursor species, the contribution of emissions from megacities to global tropospheric ozone is calculated to be 0.84%. By 2100 this contribution falls to between 0.18% and 0.62% depending on the scenario, with the lower value being for the most-polluting of the four future emissions scenarios due to stringent controls on ozone precursor emissions from highly populated areas combined with a stronger tropospheric background ozone field. The higher end of this range is from the least-polluting of the four emissions scenarios, due to lower background tropospheric ozone combined with the use of a simpler downscaling methodology in the construction of the scenario, which results in higher emissions from megacities. Although the absolute impact of megacities on global ozone is small, an important result of this study is that under all future scenarios, future air quality in megacities is expected to be less influenced by local emissions within the cities, but instead more influenced by emission sources outside of the cities, with mixing ratios of background ozone projected to play an increasing role in megacity air quality throughout the 21st century. Assumptions made when downscaling the emissions scenarios onto the grids used in such modelling studies can have a large influence on these results; future generations of emissions scenarios should include spatially explicit representations or urban development suitable for air quality studies using global chemical transport models.
Mixing of dust and NH3 observed globally over anthropogenic dust sources
Authors: Ginoux P. , Clarisse L. , Clerbaux C. , Coheur P.-F. , Dubovik O. , Hsu N. C. , Van Damme M.
Published: May 2012

Abstract. The global distribution of dust column burden derived from MODIS Deep Blue aerosol products is compared to NH3 column burden retrieved from IASI infrared spectra. We found similarities in their spatial distributions, in particular their hot spots are often collocated over croplands and to a lesser extent pastures. Globally, we found 22% of dust burden collocated with NH3. This confirms the importance of anthropogenic dust from agriculture. Regionally, the Indian subcontinent has the highest amount of dust mixed with NH3 (26%), mostly over cropland and during the pre-monsoon season. North Africa represents 50% of total dust burden but accounts for only 4% of mixed dust, which is found over croplands and pastures in Sahel and the coastal region of the Mediterranean. In order to evaluate the radiative effect of this mixing on dust optical properties, we derive the mass extinction efficiency for various mixtures of dust and NH3, using AERONET sunphotometers data. We found that for dusty days the coarse mode mass extinction efficiency decreases from 0.62 to 0.48 m2 g−1 as NH3 burden increases from 0 to 40 mg m−2. The fine mode extinction efficiency, ranging from 4 to 16 m2 g−1, does not appear to depend on NH3 concentration or relative humidity but rather on mineralogical composition and mixing with other aerosols. Our results imply that a significant amount of dust is already mixed with ammonium salt before its long range transport. This in turn will affect dust lifetime, and its interactions with radiation and cloud properties.
Heterogeneous ice nucleation on atmospheric aerosols: a review of results from laboratory experiments
Authors: Hoose C. , Möhler O.
Published: May 2012

Abstract. A small subset of the atmospheric aerosol population has the ability to induce ice formation at conditions under which ice would not form without them (heterogeneous ice nucleation). While no closed theoretical description of this process and the requirements for good ice nuclei is available, numerous studies have attempted to quantify the ice nucleation ability of different particles empirically in laboratory experiments. In this article, an overview of these results is provided. Ice nucleation onset conditions for various mineral dust, soot, biological, organic and ammonium sulphate particles are summarized. Typical temperature-supersaturation regions can be identified for the onset of ice nucleation of these different particle types, but the various particle sizes and activated fractions reported in different studies have to be taken into account when comparing results obtained with different methodologies. When intercomparing only data obtained under the same conditions, it is found that dust mineralogy is not a consistent predictor of higher or lower ice nucleation ability. However, the broad majority of studies agrees on a reduction of deposition nucleation by various coatings on mineral dust. The ice nucleation active surface site (INAS) density is discussed as a normalized measure for ice nucleation activity. For most immersion and condensation freezing measurements on mineral dust, estimates of the temperature-dependent INAS density agree within about two orders of magnitude. For deposition nucleation on dust, the spread is significantly larger, but a general trend of increasing INAS densities with increasing supersaturation is found. For soot, the presently available results are divergent. Estimated average INAS densities are high for ice-nucleation active bacteria at high subzero temperatures. At the same time, it is shown that some other biological aerosols, like certain pollen grains and fungal spores, are not intrinsically better ice nuclei than dust, but owe their high ice nucleation onsets to their large sizes. Surface-area-dependent parameterizations of heterogeneous ice nucleation are discussed. For immersion freezing on mineral dust, fitted INAS densities are available, but should not be used outside the temperature interval of the data they were based on. Classical nucleation theory, if employed with one fitted contact angle, does not reproduce the observed temperature dependence for immersion nucleation, temperature and supersaturation dependence for deposition nucleation, and time dependence.
Global marine plankton functional type biomass distributions: Phaeocystis sp.
Authors: Vogt M. , O'Brien C. , Peloquin J. , Schoemann V. , Breton E. , Estrada M. , Gibson J. , Karentz D. , Van Leeuwe M. A. , Stefels J. , Widdicombe C. , Peperzak L.
Published: May 2012

Abstract. The planktonic haptophyte Phaeocystis has been suggested to play a fundamental role in the global biogeochemical cycling of carbon and sulphur, but little is known about its global biomass distribution. We have collected global microscopy data of the genus Phaeocystis and converted abundance data to carbon biomass using species-specific carbon conversion factors. Microscopic counts of single-celled and colonial Phaeocystis were obtained both through the mining of online databases and by accepting direct submissions (both published and unpublished) from Phaeocystis specialists. We recorded abundance data from a total of 1595 depth-resolved stations sampled between 1955–2009. The quality-controlled dataset includes 5057 counts of individual Phaeocystis cells resolved to species level and information regarding life-stages from 3526 samples. 83% of stations were located in the Northern Hemisphere while 17% were located in the Southern Hemisphere. Most data were located in the latitude range of 50–70° N. While the seasonal distribution of Northern Hemisphere data was well-balanced, Southern Hemisphere data was biased towards summer months. Mean species- and form-specific cell diameters were determined from previously published studies. Cell diameters were used to calculate the cellular biovolume of Phaeocystis cells, assuming spherical geometry. Cell biomass was calculated using a carbon conversion factor for Prymnesiophytes (Menden-Deuer and Lessard, 2000). For colonies, the number of cells per colony was derived from the colony volume. Cell numbers were then converted to carbon concentrations. An estimation of colonial mucus carbon was included a posteriori, assuming a mean colony size for each species. Carbon content per cell ranged from 9 pg (single-celled Phaeocystis antarctica) to 29 pg (colonial Phaeocystis globosa). Non-zero Phaeocystis cell biomasses (without mucus carbon) range from 2.9 × 10−5 μg l−1 to 5.4 × 103 μg l−1, with a mean of 45.7 μg l−1 and a median of 3.0 μg l−1. Highest biomasses occur in the Southern Ocean below 70° S (up to 783.9 μg l−1), and in the North Atlantic around 50° N (up to 5.4 × 103 μg l−1). The original and gridded data can be downloaded from PANGAEA, http://doi.pangaea.de/10.1594/PANGAEA.779101.
Integrating MODIS images in a water budget model for dynamic functioning and drought simulation of a Mediterranean forest in Tunisia
Authors: Chakroun H. , Mouillot F. , Nouri M. , Nasr Z.
Published: May 2012

Abstract. The use of remote sensing at different spatio-temporal resolutions is being common during the last decades since sensors offer many inputs to water budget estimation. Various water balance models use the LAI as a parameter for accounting water interception, evapotranspiration, runoff and available ground water. The objective of the present work is to improve vegetation stress monitoring at regional scale for a natural forested ecosystem. LAI-MODIS and spatialized vegetation, soil and climatic data have been integrated in a water budget model that simulates evapotranspiration and soil water content at daily step. We first explore LAI-MODIS in the specific context of Mediterranean natural ecosystem. Results showed that despite coarse resolution of LAI-MODIS product (1 km), it was possible to discriminate evergreen and coniferous vegetation and that LAI values are influenced by underlying soil capacity of water holding. The dynamic of vegetation has been integrated into the water budget model by weekly varying LAI-MODIS. Results of simulations were analysed in terms of actual evapotranspoiration, deficit of soil water to field capacity and vegetation stress index based on actual and potential evapotranspiration. Comparing dynamic LAI variation, afforded by MODIS, to a hypothetic constant LAI all over the year correspond to 30% of fAPAR increase. A sensitivity analysis of simulation outputs to this fAPAR variation reveals that increase of both deficit of soil water to field capacity and stress index are respectively 18% and 27%, (in terms of RMSE, these variations are respectively 1258 mm yr−1 and 11 days yr−1). These results are consistent with previous studies led at local scale showing that LAI increase is accompanied by stress conditions increase in Mediterranean natural ecosystems. In this study, we also showed that spatial modelisation of drought conditions based on water budget simulations is an adequate tool for quantifying expositions of different species to stress and for analysing most influent factors on ecosystem vulnerability to drought.
Vertical Economies and the Costs of Separating Electricity Supply—A Review of Theoretical and Empirical Literature
Authors: Meyer Roland
Published: May 2012

Motivated by the European movement towards a separation of electricity networks from the competitive functions generation and supply this paper reviews theoretical and empirical literature on vertical synergies in electricity supply. In the analysis a clear distinction is made between four different unbundling options leading to different forms and magnitudes of synergy losses. Apart from coordination economies a main source of scope economies seems to result from a market risk effect if generation and retail are separated.

Accordingly, the European policy of network unbundling (either transmission or distribution) results in synergy losses between 2 and 8 percent due to coordination losses, while an unbundling option that includes a separation between retail and generation, as observed in some U.S. states, may lead to a permanent cost increase of 20 percent or more due to a significant risk increase. Keywords: Ownership unbundling, Vertical integration, Economies of scope

http://dx.doi.org/10.5547/01956574.33.4.8
Electrode Materials for Rechargeable Sodium‐Ion Batteries: Potential Alternatives to Current Lithium‐Ion Batteries
Authors: Kim Sung‐Wook , Seo Dong‐Hwa , Ma Xiaohua , Ceder Gerbrand , Kang Kisuk
Published: May 2012

Lithium (Li)‐ion batteries (LIB) have governed the current worldwide rechargeable battery market due to their outstanding energy and power capability. In particular, the LIB's role in enabling electric vehicles (EVs) has been highlighted to replace the current oil‐driven vehicles in order to reduce the usage of oil resources and generation of CO2 gases. Unlike Li, sodium is one of the more abundant elements on Earth and exhibits similar chemical properties to Li, indicating that Na chemistry could be applied to a similar battery system. In the 1970s‐80s, both Na‐ion and Li‐ion electrodes were investigated, but the higher energy density of Li‐ion cells made them more applicable to small, portable electronic devices, and research efforts for rechargeable batteries have been mainly concentrated on LIB since then. Recently, research interest in Na‐ion batteries (NIB) has been resurrected, driven by new applications with requirements different from those in portable electronics, and to address the concern on Li abundance. In this article, both negative and positive electrode materials in NIB are briefly reviewed. While the voltage is generally lower and the volume change upon Na removal or insertion is larger for Na‐intercalation electrodes, compared to their Li equivalents, the power capability can vary depending on the crystal structures. It is concluded that cost‐effective NIB can partially replace LIB, but requires further investigation and improvement.
Validation of mass‐transfer model for VIPS process using in situ measurements performed by near‐infrared spectroscopy
Authors: Bouyer D. , Pochat‐Bohatier C.
Published: May 2012

Combined experimental and modeling approaches were performed in order to investigate the influence of formulation and process parameters on mass transfers during VIPS process, using the water/N‐methyl‐pyrrolidone (NMP)/poly(ether imide) (PEI) system. The experiments were conducted using a thick polymer solution at increasing polymer concentrations for various operating conditions. The global water intake rate in the bulk solution was determined by gravimetric measurements (global), and insitu measurements were conducted by near‐infrared spectroscopy at three points in the solution. In parallel, a fully predictive model was developed for predicting mass‐transfer phenomena involved during the VIPS process. The comparison between experimental data and numerical predictions exhibited a good agreement for moderate polymer concentration, but for higher polymer concentrations, the model overestimated the nonsolvent‐transfer rate. This result was explained by the aggregation process of the polymer chains due to water intake. The numerical predictions were improved by modifying the average hole‐free volume expression. © 2012 American Institute of Chemical Engineers AIChE J, 59: 671–686, 2013
Deterministic vs. stochastic performance assessment of iterative learning control for batch processes
Authors: Farasat Ehsan , Huang Biao
Published: May 2012

The performance assessment of linear time‐invariant batch processes when iterative learning control (ILC) is implemented has been discussed. Previous literatures show that conventional performance assessment cannot be directly applied to batch processes due to the nature of batch operations. Chen and Kong have suggested a new method to assess the control performance of batch processes using optimal ILC as the benchmark. In their work, ILC controllers are assumed to affect either stochastic or deterministic performance but without considering their interaction. This work elaborates the controllers effects on both stochastic and deterministic control performance of batch processes. It is shown that the optimal solution based on the minimum variance control law has a trade‐off between deterministic and stochastic performance, which can be shown by a trade‐off curve. Furthermore, a method is proposed to estimate this curve from routine operating data, against which the performance of ILC controllers can be assessed. Simulation studies are conducted to verify the proposed method. © 2012 American Institute of Chemical Engineers AIChE J, 59: 457–464, 2013
Design under uncertainty of hydrocarbon biorefinery supply chains: Multiobjective stochastic programming models, decomposition algorithm, and a Comparison between CVaR and downside risk
Authors: Gebreslassie Berhane H. , Yao Yuan , You Fengqi
Published: May 2012

A bicriterion, multiperiod, stochastic mixed‐integer linear programming model to address the optimal design of hydrocarbon biorefinery supply chains under supply and demand uncertainties is presented. The model accounts for multiple conversion technologies, feedstock seasonality and fluctuation, geographical diversity, biomass degradation, demand variation, government incentives, and risk management. The objective is simultaneous minimization of the expected annualized cost and the financial risk. The latter criterion is measured by conditional value‐at‐risk and downside risk. The model simultaneously determines the optimal network design, technology selection, capital investment, production planning, and logistics management decisions. Multicut L‐shaped method is implemented to circumvent the computational burden of solving large scale problems. The proposed modeling framework and algorithm are illustrated through four case studies of hydrocarbon biorefinery supply chain for the State of Illinois. Comparisons between the deterministic and stochastic solutions, the different risk metrics, and two decomposition methods are discussed. The computational results show the effectiveness of the proposed strategy for optimal design of hydrocarbon biorefinery supply chain under the presence of uncertainties. © 2012 American Institute of Chemical Engineers AIChE J, 2012
Modeling and simulation for direct contact membrane distillation in hollow fiber modules
Authors: Ibrahim Salah S. , Alsalhy Qusay F.
Published: May 2012

Direct contact membrane distillation (DCMD) offers an attractive operation for the separation of mixtures at atmospheric pressure with reasonable energy requirement. A new simultaneous heat and mass transfer model in DCMD in a hollow fiber configuration is presented. Flow regime in feed and permeate side, the variations of mean temperature and concentration along the membrane module, the length of the membrane, and various properties of membrane characteristics are taken into account in the present model. A system of nonlinear equations describing the DCMD process is solved numerically for each cell using the FSOLVE coding, which is a built‐in function in MATLAB® to find the influence of the temperature and velocity of the feed and permeate streams, and the salt concentration of the feed along the module on the permeate flux. The predicted results by the new model show a good accord with a wide range of various experimental results available in the literature. © 2012 American Institute of Chemical Engineers AIChE J, 59: 589–603, 2013
Molecular characterization, recombinant protein expression, and mRNA analysis of type 3 von Willebrand disease: Studies of an Italian cohort of 10 patients
Authors: Solimando Maria , Baronciani Luciano , La Marca Silvia , Cozzi Giovanna , Asselta Rosanna , Canciani Maria Teresa , Federici Augusto B. , Peyvandi Flora
Published: May 2012

Type 3 von Willebrand disease (VWD3) is characterized by unmeasurable von Willebrand factor (VWF) levels in plasma and platelets and severe but variable hemorrhagic symptoms. To identify and characterize the causal mutations, we screened 10 Italian patients with VWD3 by several techniques including Multiplex Ligation‐dependent Probe Amplification to identify large insertions and deletions, High Resolution Melting and PCR coupled with Sanger sequencing. Fourteen different mutations scattered throughout the VWF gene were identified, 10 of which were novel. As expected, most of these mutations caused null alleles: five were deletions (del exons 1–3, del exon 17, c.2157delA, c.2269delCT, and c.3940delG), three nonsense (p.Q1526X, p.E1549X, and p.C2448X) and three potential splice‐site mutations (c.658‐2A>G, c.7729+7C>T, and c.8155+1G>T). Three candidate missense mutations (p.C2184S, p.C2212R, and p.C2325S) were also identified. Missense mutations and the putative splice‐site defects were confirmed to be disease related by in vitro expression studies and mRNA analysis. None of these patients have developed alloantibodies against VWF. This study extends our previous finding that most of the mutations that we identified in VWD3 patients arise independently and are scattered throughout the entire VWF gene. Am. J. Hematol. 2012. © 2012 Wiley Periodicals, Inc.