bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of State Dependent Vacation Queues with Threshold Gated Service Policy
Authors: Sing Yew
Published: April 2010

In this article, the authors introduce a simple approach for modeling and analyzing a queue where the server may take repeated vacations. When a busy period ends, the server takes a vacation of random duration. At the end of each vacation, the server may either start a new vacation or resume service. If a queue is found of less than customers, the server will always take a new vacation. If there are at least customers in queue, the server provides services to those customers after a brief set-up time. The authors obtain several performance measures of the system, including the mean and second moment of the cycle time, the number of customers in a cycle of service, and the expected delay experienced by a customer.
Performance of Two-Component Systems with Imperfect Repair
Authors: Hajeeh Mohammed
Published: April 2010

Operational systems deteriorate over time and eventually fail by the failure of one or more of their components. Failed components are either replaced or repaired, and replacement is usually expensive. This article examines the behavior of repairable systems with imperfect repair, where a failed component is repaired once or more depending on factors such as repair cost, level of deterioration, and criticality of the component. When these systems are subjected to a customer use environment, their performance must endure different conditions. In imperfect repair, the performance of the system lessens after each failure. Three models of a two-component system studied are the series, parallel, and standby configurations, and the components are identical and independent. A closed form analytical expression for steady state operational probability is derived for different configurations under exponential distribution time to failure and repair time. Two examples are then discussed thoroughly.
Strategies for Improving Open Source Software Usability
Authors: Zhao Luyin , Deek Fadi P. , McHugh James A.
Published: April 2010

The Open Source Software (OSS) movement has had enormous impact on how software is created and continues to attract interest from researchers, software developers and users. A factor that may be inhibiting OSS from achieving greater success is usability, a fundamental characteristic to user acceptance of software. Motivated by the uniquely user-driven nature of the open source model and the extensive user base that participates in OSS projects, the authors propose an exploratory learning method and an associated web-based inspection environment that enables non-experts to contribute to open source usability inspection. This tool uses patternbased usability guidelines to help identify usability knowledge during inspection. The method emphasizes outlining and exploration features which the authors have formally evaluated and the results of which are described. Data collected from a qualitative study indicates positive impact of the proposed method in helping end-users inspect software and achieve better results in discovering usability problems.
Higher Education and FOSS for e-Learning
Authors: Williams van Rooij Shahron
Published: April 2010

This paper examines the paradox of FOSS adoption in U.S. institutions of higher education, where campus-wide deployment of FOSS for e-learning lags far behind adoption for technical infrastructure applications. Drawing on the fields of organizational management, information systems, and education, the author argues that the gap between FOSS advocacy and the enterprise-wide deployment of FOSS for e-learning is a consequence of the divergent perspectives of two organizational sub-cultures—the technologist and the academic—and the extent to which those sub-cultures are likely to embrace FOSS. The author recommends (a) collaborative needs analysis/assessment prior to a go/no go adoption decision, and (b) broad dissemination of total cost of ownership (TCO) data by institutions deploying FOSS for e-learning enterprise-wide. This discussion satisfies e-learning administrators and practitioners seeking research-based, cross-disciplinary evidence about the FOSS decision-making process and also assists educators seeking to expand student knowledge of e-learning technology options.
Developing a Dynamic and Responsive Online Learning Environment
Authors: Buchan Janet
Published: April 2010

Charles Stuart University adopted the open source software, Sakai, as the foundation for the university’s new, integrated Online Learning Environment. This study explores whether a pedagogical advantage exists in adopting such an open source learning management system. Research suggests that the community source approach to development of open source software has many inherent pedagogical advantages, but this paper examines whether this is due to the choice of open source software or simply having access to appropriate technology for learning and teaching in the 21st century. The author also addresses the challenges of the project management methodology and processes in the large-scale implementation of an open-source courseware management solution at the institutional level. Consequently, this study outlines strategies that an institution can use to harness the potential of a community source approach to software development to meet the institutional and individual user needs into the future.
Open for Social
Authors: Laffey James , Schmidt Matthew , Amelung Christopher
Published: April 2010

Online learning in K-12 and higher education has been growing rapidly, and open source software has the potential to improve the quality of e-learning. This paper describes how FOSS enables turning e-learning from a potentially restrictive framing of the education experience to an emergent and social experience. The authors identify several key elements of the FOSS model that position open source initiatives to contribute to the emergent and social nature of experience in e-learning. The authors also describe several challenges to developing FOSS in a community of educators for e-learning. These elements and challenges are illustrated in a brief case report about the development of an open source software system called Context-aware Activity Notification System (CANS). CANS (http://cansaware.com) is a notification system that integrates with collaborative work and learning systems and is designed around the importance of awareness of user activity, a user’s social context and personal notification preferences.
Data Mining User Activity in Free and Open Source Software (FOSS)/ Open Learning Management Systems
Authors: McGrath Owen
Published: April 2010

Free and Open Source Software (FOSS)/Open Educational Systems development projects abound in higher education today. Many universities worldwide have adopted open source software like ATutor and Moodle as an alternative to commercial or homegrown systems. The move to open source learning management systems entails many special considerations, including usage analysis facilities. The tracking of users and their activities poses major technical and analytical challenges within web-based systems. This paper examines how user activity tracking challenges are met with data mining techniques, particularly web usage mining methods, in four different open learning management systems: ATutor, LON-CAPA, Moodle, and Sakai. As examples of data mining technologies adapted within widely used systems, they represent important first steps for moving educational data mining outside the research laboratory. Moreover, as examples of different open source development contexts, exemplify the potential for programmatic integration of data mining technology processes in the future. As open systems mature in the use of educational data mining, they move closer to the long-sought goal of achieving more interactive, personalized, adaptive learning environments online on a broad scale.
21ST Century Democratic Capitalism
Authors: Carayannis Elias G. , Kaloudis Aris
Published: April 2010

Starting on September 11, 2001, and following both actions and reactions around the world, it may well be that we have arrived at a major tipping point in terms of socio-economic development, political reform, as well as many other global issues - from financial and economic coordination to climate change as well as hunger and disease challenges in the developing world. On November 9, 1989 (more than 20 years ago), the world watched as the Berlin Wall was tumbling and with it the Cold War was slipping into memory as the morning fog. During the last two decades, progress was accomplished on many fronts but great opportunities were also missed or wasted both within the US (for instance, health care and social security reforms) as well as around the world where the Washington Consensus mantra of privatization and unbridled globalization led to the socioeconomic polarization of many former Warsaw pact countries as well as former parts of the Soviet Union and in effect made many people around the world cynical as to the capacity of free market regimes to allow for equitable and sustainable economic development along civic renaissance.
Public on Conserving an Urban Wetland
Authors: Raj P. P. Nikhil , Azeez P. A.
Published: April 2010

The present study examines responses of the public to a proposed ecotourism program. Several individuals were randomly contacted in Kerala, India, to elicit their observations and responses to the proposed program, including residents, local travelers and workers. Though a large share of the sample population supported the project, anticipating that it would accelerate the development of the city and increase their annual earnings, many were unaware of the ecological importance of the mangrove wetland. Only 5% of the total sampled populations were aware of the importance of conserving wetland ecosystems in a growing city. This exemplifies the cheerless state of the environmental consciousness of the public in Kerala, despite that the city is among the most literate, socially advanced and environmentally cognizant populations in India. This study highlights the need for development of much deeper scientific consciousness among the public at large.
Inductive Classification of Semantically Annotated Resources through Reduced Coulomb Energy Networks
Authors: Fanizzi Nicola , d’Amato Claudia , Esposito Floriana
Published: April 2010

The tasks of resource classification and retrieval from knowledge bases in the Semantic Web are the basis for a lot of important applications. In order to overcome the limitations of purely deductive approaches to deal with these tasks, inductive (instance-based) methods have been introduced as efficient and noise-tolerant alternatives. In this paper we propose an original method based on a non-parametric learning scheme: the Reduced Coulomb Energy (RCE) Network. The method requires a limited training effort but it turns out to be very effective during the classification phase. Casting retrieval as the problem of assessing the classmembership of individuals w.r.t. the query concepts, we propose an extension of a classification algorithm using RCE networks based on an entropic similarity measure for OWL. Experimentally we show that the performance of the resulting inductive classifier is comparable with the one of a standard reasoner and often more efficient than with other inductive approaches. Moreover, we show that new knowledge (not logically derivable) is induced and the likelihood of the answers may be provided.
Integrating Interactive TV Services and the Web through Semantics
Authors: Tsetsos Vassileios , Papadimitriou Antonis , Anagnostopoulos Christos , Hadjiefthymiades Stathes
Published: April 2010

Interactive TV has started to penetrate broadcasting markets, providing a new user experience through novel services to subscribers and new revenue opportunities for companies. Personalization and intelligent behavior, such as proactive content delivery are considered key features for the services of the future TV. However, most of the work in this area is limited to personalization of electronic program guides and advanced program recommendation. In this article, the authors adopt a more horizontal approach and describe the application of concepts, practices and modern Web trends to the TV domain in the context of the POLYSEMA platform. A key characteristic of this approach is the formal modeling of multimedia and user semantics that enables novel TV services. Specifically, Semantic Web methodologies are employed (e.g., ontologies and rules) while compatibility with the MPEG-7 standard is also pursued. The paper describes the overall architecture of the platform, provides implementation details and investigates business issues.
A Study of the Systemic Relationship Between Worker Motivation and Productivity
Authors: Haefner J. J. , Makrigeorgis Christos
Published: April 2010

Three well known theories on worker motivation have proliferated in the literature and practice over the past 50 years, namely Theories X, Y, Z, Expectancy Theory, Equity Theory, Justice Theory, and Goal-Setting Theory, to name a few. We propose a Fourth Theory that is based on the fundamental principles of open systems theory that function in holistic fashion into the phenomenon of systemic motivation. When fully engaged, systemic motivation can influence workers to become more productive than in a system that does not engage. It is the central construct that has been missing in motivation theory. This paper briefly explains systemic motivation and demonstrates its potential in a case study where a motivation effect resulted in an additional $1 million in product throughput.
Does Anybody Read SMS-Advertising?
Authors: Gauzente Claire
Published: April 2010

This study explores mobile users’ perceptions about SMS advertising. The empirical study uses a double methodology. First, a qualitative study using the Q-method is conducted. Qualitative analysis reveals that negative attitudes are commonly shared, and that ad-clutter is perceived critically. Therefore, in a second step, a quantitative study is adopted to assess the impact of attitudes towards SMS advertising and perceived ad-clutter on reading behaviour. The main test is conducted over a representative sample of 302 mobile owners. From a behavioural standpoint, the results show ambivalent behaviour in most cases. In particular, the role of perceived ad-clutter is ascertained. Implications for practice and directions for future research are discussed.
Expanding Opportunities in a Shrinking World
Authors: Datta Avimanyu , Jessup Len
Published: April 2010

The authors present a parsimonious theoretical model that illustrates how Internet-based virtual environments (such as social networking Web sites) moderate the relationship between social networks and social entrepreneurship. Social networks promote social entrepreneurship by means of (a) technology and knowledge transfer; (b) locating information; (c) generating entrepreneurial opportunities; (d) building entrepreneurial competency; (e) financing innovation; and (f) building effective networks for commercialization of innovations. Internet based virtual environments increase the velocity with which online social networks are formed and operationalized. They, thus, have a moderating effect in the relationship between social networks and social entrepreneurship. The authors also represent three concepts that are core to social networks: density, centrality, and heterogeneity. They posit that all three explain variance in social entrepreneurship and that Internet-based virtual environments moderate each of the relationships these three elements of social networks have with social entrepreneurship.
Use and Participation in Virtual Social Networks
Authors: Pagani Margherita , Hofacker Charles
Published: April 2010

Managers are increasingly interested in the social web, as it provides numerous opportunities for strengthening and expanding relationships with customers, but the network processes that lead to these user-based assets are poorly understood. In this paper, the authors explore factors influencing use and participation in virtual social networks. They also discuss unusual drivers and inhibitors present with virtual social networksâ€”highlighted by the presence of positive network externalities and fears that the content will be misused. The authors offer hypotheses stemming from a model of how these factors work together, test the model with a dataset collected from two different virtual social networks, and discuss the implications of this work. The findings offer managers insights on how to nurture Web 2.0 processes.
Effects of Computer Self Efficacy on the Use and Adoption of Online Social Networking
Authors: Mew Lionel , Money William H.
Published: April 2010

Online Social Networking (OSN) systems such as Ning, MySpace, Facebook and Friendster have achieved tremendous popularity. However, little research has been conducted to determine factors motivating users with varying capabilities to use and adopt OSN systems addressing target tasks, with varying system capabilities and characteristics. The relationships between user characteristics and use/performance have not been adequately addressed. This study used a cross-sectional survey of 262 graduate and undergraduate students to examine how end user Computer Self-Efficacy (CSE) affects performance and use of OSN systems and how â€œfitâ€ determines whether there are user, task and/or systems characteristics associated with the best performance and usage levels. Significant direct and indirect relationships were found between CSE, task and system characteristics as measured by performance and use, and these relationships were further significantly strengthened when there was good â€œfitâ€ between the variables. Results indicate that users having high self-efficacy â€œfitâ€ with task or systems characteristics produce higher performance and use.
Does Technology Uptake Convert to Effectiveness
Authors: Mital Monika
Published: April 2010

In this paper, the author focuses on learner perceptions of the characteristics of learning technology as explanatory variables for acceptance behavior. The author presents an empirical study examining the effects of these perceptions on two outcomes: uptake of an e-learning technology and effectiveness of such technologies that results in the intention to continue to use. The effectiveness of e-learning programs are dependent on the fulfillment of the leaner expectations in terms of the suitability of the learning to the present task, applicability of the learning, and the right incentives and measures to encourage and motivate employees.
DiALog
Authors: Ringelstein Christoph , Staab Steffen
Published: April 2010

Service-oriented systems facilitate business workflows to span multiple organizations (e.g., by means of Web services). As a side effect, data may be more easily transferred over organizational boundaries. Thus, privacy issues arise. At the same time, there are personal, business and legal requirements for protecting privacy and IPR and allowing customers to request information about how and by whom their data was handled. Managing these requirements constitutes an unsolved technical and organizational problem. The authors propose to solve the information request problem by attaching meta-knowledge about how data was handled to the data itself. The authors present their solution, in form of an architecture, a formalization and an implemented prototype for logging and collecting logs in service-oriented and cross-organizational systems.
Flexible Probabilistic QoS Management of Orchestrations
Authors: Rosario Sidney , Benveniste Albert , Jard Claude
Published: April 2010

In this paper, the authors develop a comprehensive framework for QoS management based on soft probabilistic contracts. The authors approach also encompasses general QoS parameters, with “response time” as a particular case. In addition, the authors support composite QoS parameters, for example, combining timing aspects with “quality of data” or security level. They also study contract composition (how to derive QoS contracts for an orchestration from the QoS contracts with its called services), and contract monitoring.
A Dependable Infrastructure for Cooperative Web Services Coordination
Authors: Pelinson Alchieri Eduardo Adilio , Bessani Alysson Neves , da Silva Fraga Joni
Published: April 2010

A current trend in the web services community is to define coordination mechanisms to execute collaborative tasks involving multiple organizations. Following this tendency, in this paper the authors present a dependable (i.e., intrusion-tolerant) infrastructure for cooperative web services coordination that is based on the tuple space coordination model. This infrastructure provides decoupled communication and implements several security mechanisms that allow dependable coordination even in presence of malicious components. This work also investigates the costs related to the use of this infrastructure and possible web service applications that can benefit from it.
Preparation and Characterization of Anti-Oxidation Coatings for Sliding Plates
Authors: Wang Li Na , Fan Bing Bing , Zhang Rui , Wang Hai Long , Chen De Liang
Published: April 2010

High-temperature anti-oxidation coating was prepared by a milling process, which mainly composed of flake graphite and hexagonal BN (hBN). The coating was brushed on the sliding plate surface and dried in air for 24 h, The surface of the sliding plate painted was smooth and without peeling, suggesting a strong bonding strength. The samples were heated at 1200 °C for 20 min to evaluate the mass-loss rate. The mass-loss rate of the slide gate painted is 3.7%, less than the un-painted 5.1%. XRD and SEM techniques were used to characterize the as-heated samples. The results showed that the surface of the slide plate painted was skin rolling. And the graphite reacted with oxygen at an elevated temperature to reduce oxygen concentration. In addition, hBN also reacted with oxygen to form B2O3, which also has an oxygen-resistant role in the sliding plates. These coatings exhibited unique oxidation-resistant properties, and the service life of the coated sliding plates was obviously improved.
Hot Press Sintering Behavior of Nano-Sized AlN Powders
Authors: Li Hong Bo , Luo Jun Ting , Gu Yong Fei , Xu Yan Xia
Published: April 2010

Aluminum nitride (AlN) is a stoichiometric compound with the hexagonal wurtzite structure. AlN has excellent thermal conductivity and good properties as electronic insulator. It displays good mechanical resistance up to elevated temperatures and is resistant against corrosion by molten metals. Bulk AlN may therefore be used as a refractory structural material as well as a substrate for high power microelectronic devices. However, it is very difficult for sintering high-density AlN at lower temperature than 1800°C. Nano-sized AlN powders were sintered by hot press sintering at low temperature of 1500~1700°C and mechanical properties were investigated. β-AlN and β-Al2O3 were detected when the sintering temperature is 1600°C. The phase transition β-AlN to α-AlN was discovered at a 1700°C sintering temperature. Relative density and average grain size were increasing with the increasing of sintering temperature, and fracture form is intercrystalline crack in 1500°C and transcrystalline crack in 1700°C. 97.3% relative density and 850nm average grain size were deserved at 1700°C.
Pattern of greenhouse gas emission from a Prairie Pothole agricultural landscape in Manitoba, Canada
Authors: Dunmola A S , Tenuta M. , Moulin A P , Yapa P. , Lobb D A
Published: April 2010

To obtain accurate N2O and CH4 emission estimates from the Prairie Pothole Region of North America, knowledge of landscape pattern and soil factors is important. A field study was conducted investigating the temporal and spatial variation in N2O and CH4 emissions from spring to fall 2005 and spring-thaw to post-fertilizer application period 2006 using static-vented chambers located at upper, middle and lower landscape elements planted to spring wheat in 2005 and flax in 2006 and riparian areas in an undulating terrain in southern Manitoba. N2O was emitted during spring-thaw and post-fertilizer application periods for cropped positions and CH4 was emitted about 7 wk after soil thaw for lower and riparian elements. While there was no statististical difference in N2O emission from upper, middle and lower landscape elements, there was greater occurrence of N2O emission hotspots at the lower element, associated with its comparatively higher soil moisture and carbon availability. A location of intense CH4 emission in a riparian area had considerably less soil sulfate compared with other riparian locations. We conclude that hotspots for N2O and CH4 emission within the landscape are localized and driven by high soil moisture and C availability, and riparian areas should be identified separately from cropped areas, as their N2O and CH4 emissions are lower and higher, respectively. Riparian areas having high sulfate concentrations do not seem to emit appreciable amounts of CH4.Key words: Greenhouse gas emission, landscape element, landscape variability, methane, nitrous oxide, Prairie Pothole Region, sulfate
Residues from a buckwheat (Fagopyrum esculentum) green manure crop grown with phosphate rock influence bioavailability of soil phosphorus
Authors: Arcand M M , Lynch D H , Voroney R P , van Straaten P.
Published: April 2010

Low soil test phosphorus (P) concentrations are common in organically managed soils in Canada. This field study examined the effect of residues from a buckwheat (Fagopyrum esculentum) green manure (GM) crop grown with an igneous and a sedimentary source of phosphate rock (PR) on in situ soil P supply, Olsen P, and soil microbial biomass P on an organic farm in Ontario, Canada. Phosphate rock application did not increase GM dry matter production, but did increase above-ground tissue P concentration with applications of the sedimentary PR (Calphos). In the following spring, in situ soil P supply and Olsen P were increased in GM residue-applied soils and in soils containing the Calphos PR, while microbial biomass P was largely unaffected. Release of P was detected when GM P concentration was greater than 2.9 g P kg-1. The results suggest the quality of the GM residues had more influence on P availability than the quantity applied to the soil; however, the low changes in available P (P supply and Olsen P) were not agronomically significant. Key words: Phosphate rock, soil phosphate supply, Olsen P, organic agriculture, green manure
Available nitrogen and phosphorus in soil amended with fresh or composted cattle manure containing straw or wood-chip bedding
Authors: Miller J J , Beasley B W , Drury C F , Zebarth B J
Published: April 2010

Limited research exists on the effect of fresh versus composted beef cattle manure containing straw or wood chips on available N and P in the Great Plains region of North America. Barley was grown (1999-2007) on an irrigated clay loam soil in southern Alberta where organic amendments and fertilizer were applied annually for 9 yr from 1998 to 2006. The treatments were three rates (13, 39, 77 Mg dry wt. ha-1) of fresh manure (FM, stockpiled for up to 2 m) or composted manure (CM) containing either straw (ST) or wood chip (WD) bedding, one inorganic (IN) fertilizer treatment, and a unamended control. The soil was sampled in the fall of 1999 to 2002, 2004, 2006, and 2007 and was analyzed for soil inorganic N (SIN), NO3-N, NH4-N, and soil test P (STP). Soil mineralizable N was also determined on surface soil samples collected from 1999, 2002, 2004, and 2007. Manure type had a significant effect on SIN, NO3-N, STP, and soil mineralizable N, but the effects varied with year or bedding and rate (SIN), rate or year (NO3-N), rate and year (soil mineralizable N), or bedding and year (STP). Analysis of covariance for total N or P applied versus SIN or STP after nine applications (2007) indicated greater N release for FM and CM bedded with straw than with wood, whereas P release was similar for FM and CM with straw or wood. Soil NO3-N for the organic amendments exceeded the maximum agronomic limit of 21 mg NO3-N kg-1 for Alberta after 6, 4, and 3 yr of application at the three increasing application rates. The STP for the organic amendments exceeded the maximum agronomic limit of 60 mg kg-1 for Alberta after 4, 2, and 2 yr of application at the three increasing rates. Overall, manure type and bedding material influenced the potential for nutrient losses to the environment through accumulation of soil inorganic N and soil test P; however, their effects on nutrient accumulation varied with year and application rate. Key words: Soil available nitrogen, soil available phosphorus, fresh manure, composted manure, mineralizable N
Nitrogen speciation in fine and coarse clay fractions of a Cryoboroll - new evidence from pyrolysis-mass spectrometry and nitrogen K-edge XANES
Authors: Leinweber P. , Jandl G. , Eckhardt K -U. , Kruse J. , Walley F L , Khan M J , Blyth R I.R. , Regier T.
Published: April 2010

Soil clay fractions are usually enriched in nitrogen (N), but the chemical identity of this N is largely unknown. Therefore, we investigated organic N in fine and coarse clay of a clay-rich Cryoboroll by Curie-point pyrolysis-gas chromatography/mass spectrometry (Cp Py-GC/MS), Pyrolysis-field ionization mass spectroscopy (Py-FIMS) and synchrotron-based nitrogen K-edge X-ray absorption near edge structure (N-XANES) spectroscopy. The Cp Py-GC-MS revealed 30 structurally different N-containing compounds, such as substituted pyridines, pyrroles; pyrazines, pyrazoles, imidazoles, quinolines, side-chain N-containing benzenes, and single compounds of substituted benzotriazole, purine and indole. These accounted for about 10% of peak area in the Py-GC chromatograms. The Py-FIMS and N-XANES spectra indicated interlayer-NH4+ and revealed pyridinic and nitrilic N compounds, but disagreed in the proportions of pyrroles. All three complementary methods confirmed to different extents previous wet-chemical data on N-fractions in these samples, and provided new evidence for about 30 to 40% non-proteinaceous N as major constituent of the so-called “unknown organic N” in soil. Key words: Soil clay, organic matter, pyrolysis-mass spectrometry, synchrotron, X-ray absorption, NEXAFS
Influence of landscape on the apportionment of Ca nutrition in a Boreal Shield forest of Saskatchewan (Canada) using 87Sr/86Sr as a tracer
Authors: Bélanger N. , Holmden C.
Published: April 2010

A 87Sr/86Sr tracer technique was used to apportion the supply of calcium (Ca) between atmospheric deposition and soil mineral weathering in a pristine Boreal Shield forest of northern Saskatchewan. To assess the impact of landscape variability on soil mineral weathering 87Sr/86Sr ratios, the watershed was divided into six study plots at low, middle, and high elevations along two toposequences - one consisting of mixed woods and the other consisting of black spruce. Apportionment analysis shows that none of the trees in the study plots depend entirely on soil mineral weathering as a source of Ca. Calcium pools in trees are shifted towards the atmospheric end-member (31-98%), probably because of the low soil mineral weathering fluxes combined with relatively high atmospheric deposition fluxes. These results need to be considered as the consequence of buildup and recycling of atmospherically derived Ca in the soil-vegetation system rather than the direct and large use of current atmospheric Ca inputs by the trees on an annualized basis. We also find that the trees in the high-elevation plots contain more Ca from atmospheric sources (84-98%) than trees in middle (31-86%) and low (37-82%) elevation plots. Two mechanisms are proposed to explain these results. First, if each plot is assumed to receive a constant supply of atmospherically derived Ca, then hillslope changes in soil mineral weathering rates are required to explain the changing proportions of atmospherically derived Ca cycling internally within each plot. Second, trees on hilltops may capture more dry aerosols than trees that are more shielded from atmospheric circulation in the valleys. Our work supports previous Ca cycling models in other forested ecosystems suggesting that much of the Ca requirement in trees is met via the flux from the atmosphere, but adds knowledge with regards to the role of topographical effects and forest canopy height as local factors that can influence the balance of Ca captured from atmospheric sources and released from soil mineral weathering sources. Key words: Boreal forest, calcium cycling, atmospheric deposition, soil mineral weathering, strontium isotopes, 87Sr/86Sr, calcium to strontium ratios, Sr/Ca; forest floor, tree calcium pools
Influence of controlled-release urea on seed yield and N concentration, and N use efficiency of small grain crops grown on Dark Gray Luvisols
Authors: Malhi S S , Soon Y K , Grant C A , Lemke R. , Lupwayi N.
Published: April 2010

Field experiments were conducted on Dark Gray Luvisolic soils (Typic Cryoboralf) from 2004 to 2006 (wheat-canola-barley rotation) near Star City, Saskatchewan, and from 2004 to 2007 (barley-canola-wheat-barley rotation) near Beaverlodge, Alberta. The aim was to compare the effects of controlled-release urea (CRU) vs. conventional urea (hereafter called urea) on seed yield and N (i.e., protein) concentration, and N use efficiency (NUE). The treatments were combinations of tillage system [conventional tillage (CT) and no tillage (NT)], and N source (urea, CRU and a blended mixture), placement method (spring-banded, fall-banded and split application) and application rate (0-90 kg N ha-1). There was no tillage × fertilizer treatment interaction on the measured crop variables. Seed yield and crop N uptake and, to a lesser degree, seed N concentration generally increased with N application to 90 kg N ha-1. Fall-banded CRU or urea generally produced lower crop yield and N uptake than spring-banded CRU or urea. Split application of urea (half each at seeding and tillering) resulted in higher seed yield and N concentration in at least 3 of 7 site-years than did CRU and urea applied at a similar rate. A blend of urea and CRU was as effective as spring-banded CRU (at Star City only). Seed yield, N recovery and NUE were higher with spring-banded CRU than urea in 2 site-years, and similar to urea in other site-years. We conclude that for boreal soils of the Canadian prairies, spring-banded CRU is as effective as urea, and in some years more effective, in increasing crop yield and N recovery; however, urea split application can be even more effective in addition to having an advantage in managing risk.Key words: Controlled-release urea, Gray Luvisol, nitrogen source, nitrogen recovery, nitrogen use efficiency, tillage systems
ZAP‐70 expression is associated with increased risk of autoimmune cytopenias in CLL patients
Authors: Zanotti Roberta , Frattini Franzesco , Ghia Paolo , Visco Carlo , Zamò Alberto , Perbellini Omar , Stella Stefania , Facco Monica , Giaretta Ilaria , Chilosi Marco , Pizzolo Giovanni , Ambrosetti Achille
Published: April 2010

Autoimmune cytopenias (AIC) are frequent in chronic lymphocytic leukemia (CLL) patients, but risk factors and prognostic relevance of these events are controversial. Data about the influence on AIC of biological prognostic markers, as ZAP‐70, are scanty. We retrospectively evaluated AIC in 290 CLL patients tested for ZAP‐70 expression by immunohistochemistry on bone marrow biopsy at presentation. They were 185 men, median age 63 years, 77.9% Binet stage A, 17.6% B and 4.5% C. AIC occurred in 46 patients (16%): 31 autoimmune hemolytic anemias, 10 autoimmune thrombocytopenias, four Evans syndromes, and one pure red cell aplasia. Of the 46 cases of AIC, 37 (80%) occurred in ZAP‐70 positive patients and nine (20%) in ZAP‐70 negatives. ZAP‐70 expression [Hazard Ratio (HR) = 7.42; 95% confidence interval (CI): 2.49–22.05] and age >65 years (HR = 5.41; 95% CI: 1.67–17.49) resulted independent risk factors for AIC. Among the 136 patients evaluated both for ZAP‐70 expression and IGHV status, the occurrence of AIC was higher in ZAP‐70 positive/IGHV unmutated cases (35%) than in patients ZAP‐70 negative/IGHV mutated (6%) or discordant for the two parameters (4%; P < 0.0001). In ZAP‐70 positive patients, occurrence of AIC negatively influenced survival (HR = 1.75; 95% CI: 1.06–2.86). The high risk of developing AIC in ZAP‐70 positive CLL, particularly when IGHV unmutated, should be considered in the clinical management. Am. J. Hematol. 2010. © 2010 Wiley‐Liss, Inc.
Adaptive fuzzy controller design with observer for a class of uncertain nonlinear MIMO systems
Authors: Liu Yan‐Jun , Tong Shao‐Cheng , Li Tie‐Shan
Published: April 2010

In this paper, an adaptive fuzzy control approach is proposed to stabilize a class of uncertain nonlinear MIMO systems with the unmeasured states and the external disturbances. The fuzzy logic systems are used to approximate the unknown functions. Because it does not required to assume that the system states are measurable, it needs to design an observer to estimate the system unmeasured states. The considered MIMO systems are more general, i.e. they consist of N subsystems and each subsystem is in the non‐affine form. The stability of the closed‐loop system is verified by using Lyapunov analysis method. Two simulation examples are utilized to verify the effectiveness of the proposed approach. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Short‐term travel speed prediction models in car navigation systems
Authors: Lee Seungjae , Lee Young‐Ihn , Cho Bumcheol
Published: April 2010

The objective of this study is the development of the short‐term prediction models to predict average spot speeds of the subject location in the short‐term periods of 5, 10 and 15 minutes respectively. In this study, field data were used to see the comparison of the predictability of Regression Analysis, ARIMA, Kalman Filtering and Neural Network models. These field data were collected from image processing detectors at the urban expressway for 17 hours including both peak and non‐peak hours. Most of the results were reliable, but the results of models using Kalman Filtering and Neural Networks are more accurate and realistic than those of the others.
Formation of spray‐dried powder of S‐adenosyl‐L‐methionine
Authors: Lauruengtana Vichuta , Yanagita Arisa , Neoh Tze Loon , Furuta Takeshi , Kanai Muneyoshi , Iefuji Haruyuki , Yoshii Hidefumi
Published: April 2010

S‐Adenosyl‐L‐methionine (SAM) is an essential metabolite in all living organisms. In clinical research, SAM has also been suggested as a chemotherapeutic agent in various diseases. The main problem of SAM is its instability at high temperatures, at neutral and alkaline pH, and in the presence of humidity. SAM retention in spray‐dried powder was determined under various conditions of spray‐drying. The highest SAM retention was obtained when maltodextrin (dextrose equivalent, DE, of 25) was used as the carrier solid with the SAM feed liquid at pH 4.0. The water content in the powder had a significant effect on the stability of SAM. SAM powder with lower water content exhibited higher stability.
Generation of stable cell clones expressing mixtures of human antibodies
Authors: de Kruif John , Kramer Arjen , Nijhuis Roy , van der Zande Vanessa , den Blanken Renate , Clements Carina , Visser Therèse , Keehnen Rob , den Hartog Marcel , Throsby Mark , Logtenberg Ton
Published: April 2010

Therapeutic monoclonal antibodies, a highly successful class of biological drugs, are conventionally manufactured in mammalian cell lines. A recent approach to increase the therapeutic effectiveness of monoclonal antibodies has been to combine two or more of them; however this increases the complexity of development and manufacture. To address this issue a method to efficiently express multiple monoclonal antibodies from a single cell has been developed and we describe here the generation of stable cell clones that express high levels of a human monoclonal antibody mixture. PER.C6® cells were transfected with a combination of plasmids containing genes encoding three different antibodies. Clones that express the three corresponding antibody specificities were identified, subcloned, and passaged in the absence of antibiotic selection pressure. At several time points, batch production runs were analyzed for stable growth and IgG production characteristics. The majority (11/12) of subclones analyzed expressed all three antibody specificities in constant ratios with total IgG productivity ranging between 15 and 20 pg/cell/day under suboptimal culture conditions after up to 67 population doublings. The growth and IgG production characteristics of the stable clones reported here resemble those of single monoclonal antibody cell lines from conventional clone generation programs. We conclude that the methodology described here is applicable to the generation of stable PER.C6® clones for industrial scale production of mixtures of antibodies. Biotechnol. Bioeng. 2010;106: 741–750. © 2010 Wiley Periodicals, Inc.
Effect of biodiesel‐derived waste glycerol impurities on biomass and 1,3‐propanediol production of Clostridium butyricum VPI 1718
Authors: Chatzifragkou Afroditi , Dietz David , Komaitis Michael , Zeng An‐Ping , Papanikolaou Seraphim
Published: April 2010

Aim of the present study was to assess and evaluate the impact of various kinds of impurities of biodiesel‐derived raw glycerol feedstock, upon microbial growth and 1,3‐propanediol (1,3‐PDO) production by Clostridium butyricum. Preliminary trials in 200‐mL anaerobic bottles revealed that the presence of NaCl at a concentration of 4.5% (w/w of glycerol) in growth medium imposed an evident inhibitory effect, in contrast with phosphoric salts. However, the application of NaCl at elevated quantities during batch bioreactor experiments [up to 30% (w/w of glycerol)], did neither affect the microbial growth, nor the 1,3‐PDO production. Moreover, when oleic acid was added into the growth medium at 2% (w/w of glycerol), a total preclusion of the strain was observed. In order to further investigate whether the nature of oleic acid itself or the presence of the double bond induced the inhibitory phenomenon, stearic acid was added into the medium at the same concentration (2%, w/w, of glycerol). Indeed, no inhibitory effect was observed in the fermentor, suggesting that the presence of the double bond may play a key role in the growth behavior of the microorganism. Finally, methanol effect was tested in batch and continuous bioreactor operations. Interestingly enough, the alcohol addition did not affect the microbial bioconversion of glycerol into 1,3‐PDO, even when imposed at relatively high concentrations (10%, w/w, of glycerol) in batch‐bioreactor operations. In continuous experiments, methanol was added when steady state had been achieved, and although in one case high concentration was added into the chemostat (5 g/L), the system re‐obtained a steady state without indications of negative effect upon biomass production due to the alcohol. Biotechnol. Bioeng. 2010;107: 76–84. © 2010 Wiley Periodicals, Inc.
Optimized delignification of wood‐derived lignocellulosics for improved enzymatic hydrolysis
Authors: Cullis Ian F. , Mansfield Shawn D.
Published: April 2010

One of the major bottlenecks in the bioconversion of lignocelluosic feedstocks to liquid ethanol is the recalcitrance of residue following pretreatment, specifically softwood derived residues. Peroxide delignification has previously been shown to effectively aid in the removal of condensed lignaceous moieties from substrates following pretreatment, and thereby improve the hydrolyzability of the polymeric carbohydrates to their monomeric constituents. Despite the effectiveness of peroxide, drawbacks in this system still remain, as the concentration of peroxide required for adequate hydrolysis performance is currently uneconomical. In an attempt to improve the efficacy of the delignification process, we evaluated other post‐treatment operations and concurrently attempted to limit the decomposition of peroxide loading; with the over arching aim to improve the efficiency of the bioconversion process. By employing several peroxide stabilizers and pre‐chelating the steam exploded recalcitrant substrates, we were able to substantially improve the delignification treatment of Douglas‐fir wood chips, and to reduce peroxide loading by more than 50% without negative effects on the hydrolysis rates and yield. Biotechnol. Bioeng. 2010;106: 884–893. © 2010 Wiley Periodicals, Inc.
Das Präkambrium. Die Wiege des Lebens
Authors: Linnemann Ulf , Hofmann Mandy
Published: April 2010

Das Präkambrium ist die Wiege des Lebens und nimmt mit etwa 4 Milliarden Jahren den größten Teil der Erdgeschichte ein. Das Leben veränderte den Planeten in diesem Zeitraum durch viele Wechselwirkungen mit der Plattentektonik und steigerte sich dabei in eine immer höhere Qualität. Ein besonderer Meilenstein war die Freisetzung großer Mengen von Sauerstoff durch die Stromatolithe vor etwa 2,5 Milliarden Jahren. Ein extremer Flaschenhals für die Evolution des Lebens war die Schneeball‐Erde vor 635 Millionen Jahren, die das Zufrieren des gesamten Planeten und dessen Bedeckung mit einem Eispanzer bedeutete. Nachdem plattentektonische Prozesse das Abtauen der weltweiten Eisdecke bewirkten, setzte die Radiation der ersten komplexen höheren Lebewesen ein. Dies waren die Ediacara‐Biota im Zeitraum von etwa 630 bis 543 Millionen Jahren vor heute. Diese in der Evolution einzigartigen Lebewesen existierten in einer engen Wechselbeziehung mit einer lederartigen Biomatte am Meeresboden, die Stabilisierung, Schutz und Nahrung bot. Unter den Ediacara‐Biota treten die ersten primitiven Arthropoden, Mollusken und Anthozoa auf. Es gibt aber auch in der fossilen Überlieferung viele geheimnisvolle Lebensformen ohne sichere Zuordnung. Die Ediacara‐Biota repräsentieren den entscheidenden evolutionären Schritt, um die explosionsartige Radiation der Lebewesen im Kambrium vor etwa 542 Millionen Jahren zu ermöglichen.
Die Fermentation von Sauerkraut. Das Experiment
Authors: Keßler Kai , Kunz Peter M. , Sommer Isabell
Published: April 2010

Der Artikel behandelt die Herstellung von Sauerkraut und liefert Hintergrundinformationen zu diesem Thema. Darüber hinaus werden Möglichkeiten zur Prozessverfolgung und Qualitätsüberprüfung aufgeführt. Im weiteren Verlauf wird auf die Veranschaulichung und Bestimmung der Wachstumskinetik nach Monod eingegangen. Der Artikel kann als Praktikumsvorlage für Versuche in Schule und Studium herangezogen werden.
100 Jahre “Vogelwarte Helgoland”
Authors: Bairlein Franz
Published: April 2010

Am 1. April 1910 wurde das heutige Institut für Vogelforschung als “Vogelwarte Helgoland” auf Helgoland gegründet. Seit 1947 befindet sich das Institut in Wilhelmshaven und ist seither ein außeruniversitäres Forschungsinstitut des Landes Niedersachsen. Der Kunstmaler Heinrich Gätke (1814–1897) hat als erster auf die Bedeutung Helgolands für den Vogelzug aufmerksam gemacht und mit seinem 1891 erschienenen Buch “Die Vogelwarte Helgoland” sowie seiner umfangreichen Vogelsammlung den Anstoß für die Gründung der Forschungsstation gegeben.
Überraschungsfund im Botanischen Garten
Authors: Schneckenburger Stefan
Published: April 2010

Durch die Medien geistern immer wieder Geschichten über ein Rembrandt‐Gemälde auf dem Speicher oder eine Gutenbergbibel im Bücherregal. Nicht ganz so hoch kann ein Pflanzenfund im Botanischen Garten der Technischen Universität Darmstadt eingeschätzt werden – dennoch ist die Entdeckung des Palmfarms Dioon caputoi bemerkenswert und auch unter Artenschutzaspekten bedeutsam.
Thiotimolin und Reproduktion von Tribbles (Polytrichon oviformis)
Authors: Schneider Thomas , Haink Nina
Published: April 2010

Durch die Verabreichung von Thiotimolin gelang eine experimentelle Generationszeitverkürzung bei Tribbles (Polytrichon oviformis), die zur Vermehrung der Tiere bereits vor der Reproduktion führt. Experimente weisen darauf hin, dass hierfür ein bisher unbekannter Thiotimolin‐Protein‐Komplex verantwortlich ist.