bluuebunny/crossref_metadata_2025 huggingface dataset:
Immigration policy, public libraries and the social practice of exclusion in Canada
Authors: MacDonald Susan
Published: January 2013

Canada's immigration policies have historically constituted a social practice of exclusion that privileges the hegemonic project of one social identity over that of another, namely the capitalist state over other social relations in society. Using critical discourse analysis, this doctoral dissertation project examines the ways in which the state's constitution of immigrant communities and their relationships with state institutions, such as the public library, represents one site where such hegemonic struggles unfold. This research addresses the question: As an institute of the state and product of public policy, what role has the public library played in constituting immigrants to Canada and in what ways have these practices contributed to the inclusion or exclusion of immigrants in Canadian society?
Practice theory and work task performance: How are they related and how can they contribute to a study of information practices
Authors: Byström Katriina , Lloyd Annemareé
Published: January 2013

Our aim is to introduce an emerging understanding of how practice theory can be used to frame the analysis of (work) task‐based research. This analytical work is tentative, but has the capacity of furthering task‐based research by addressing the dialogical relationships and embodied performances that constitute practice. We argue that analyses of task as a constitute element of practice can contribute to a rich discussion of knowledge construction in information studies.
Conceptualizing emergent archival forms: A case study of the occupy wall street “archive”
Authors: Lischer‐Katz Zack
Published: January 2013

In this paper, the author begins to conceptualize how online archival collections can be understood and evaluated. The author uses the Occupy Wall Street archives project as a case study for looking at this new form of archive, one constituted by multiple collecting institutions. Expanding the concept of interface as a tool for examining an archival collection that transcends typical physical demarcation, the author analyzes the links and navigation between different archival websites and institutions, and draws conclusions about the nature of these new types of archival collections. This paper provides a new approach for research into online archives, suggesting future avenues of inquiry, including future work on studying user behavior within online archives.
Mobile web interface of academic libraries
Authors: Han Hyejung , Jeong Wooseob
Published: January 2013

More and more academic libraries are offering their services via a mobile web platform. This study examined the current status of the mobile web interface of academic libraries in terms of their usability and tried to suggest an effective mobile service design for academic libraries. Seventy‐six mobile academic library web sites were identified. Their first pages were captured and their menu systems were analyzed for different aspects, such as frequently appearing menu items, a search box and search links, URL hiding, menu icons and textual menus. We found many undesirable interfaces that waste space or cause users to be confused. A significant gap between users' needs and the services offered was also identified. To overcome this gap, more efforts should be made in finding users' needs first and implementing services as much as possible to meet such demands.
Checking in: A phenomenological study of active users of geolocational tagging services
Authors: Smith Carol E.
Published: January 2013

Geosocial check‐in services are a relatively new feature of social media, used by a small but growing percentage of social networking enthusiasts. The purpose of this exploratory phenomenological study is to develop an initial qualitative understanding of the practices, interests, needs, and motivations of active users of mobile geosocial check‐in services, and the meaning that they ascribe to the use of geotagging services in their daily life. Through interview analysis and rich description, five key themes emerge. Geosocial check‐in services are found to be more than just a novel feature present in social media applications – users employ them to bind together the internal, social, and virtual dimensions of their modern lives, and to situate these dimensions in relation to the physical world around them.
Structural analysis of author vector space in the field of information sciences
Authors: Joo Soohyung , Lu Kun
Published: January 2013

In this poster we analyze the structure of author relationships using structural equation modeling (SEM). A structural model of four research areas and associated authors was examined in the author vector space in information sciences. The SEM result confirmed that the selected authors were adequately explained by their specific research area in the vector space based on author publications. In addition, we found that the research areas of “Information retrieval” and “Webometrics & Search log analysis” were closely related to each other.
J.J. Gibson and Marshall McLuhan: A survey of terminology and a proposed extension of the theory of affordances
Authors: Overhill Heidi
Published: January 2013

Psychologist James J. Gibson coined the word “affordance” in 1979, to describe the relationship between the abilities of a living creature, and features in the environment that afford action for those abilities. An affordance, therefore, is physically real, but is defined as an affordance only in reference to a particular creature. This term has been widely adopted, and is now found in design, education, and cognitive science. Sometimes it is used in Gibson's original meaning, but it has also been applied to broader discussions of social and cognitive activities, resulting in a certain confusion of terminology. A short summary reveals the variety of current uses for the term, and goes further to propose that this range may be simplified by applying Marshall McLuhan's observation that “media are the extensions of mankind.” In that analysis, an object like a cup is an extension of cupped hands, because, like hands, it holds water. Defining some objects as body‐extensions makes it clear that affordances can be modified in two ways: by changing either features that are available in the environment, or the extended abilities of the user. This distinction simplifies the description of different types of affordances, and may help designers in planning effective experiences for users.
Information manipulation classification theory for LIS and NLP
Authors: Rubin Victoria L. , Chen Yimin
Published: January 2013

The Information Manipulation Classification Theory offers a systematic approach to understanding the differences and similarities among various types of information manipulation (such as falsification, exaggeration, concealment, misinformation or hoax). We distinguish twelve salient factors that manipulation varieties differ by (such as intentionality to deceive, accuracy, and social acceptability) to provide an abstract framework and conceptualize various permutations. Each variety then is represented as a set of features in the twelve‐dimensional space. Our contributions are two‐fold. In Library and Information Science (LIS) literature, a nuanced understanding of information manipulation varieties and their inter‐relation lends greater awareness and sophistication to the ways we think about information and information literacy. For Natural Language Processing (NLP), the model identifies salient features for each manipulation variety, creates a potential for automated recognition and adaptability from deception detection technology to identification of other information manipulation varieties based on similarities.
The role of purpose, approach‐avoidance, self‐efficacy, intolerance of uncertainty, and locus of control in undergraduates' source selection
Authors: Williams Rachel D. , Kim Kyung‐Sun
Published: January 2013

The primary objective of this research study poster is to explore differences in sources selected by undergraduate students in relation to two factors: 1) purpose of search, and 2) scores on the Problem‐Solving Inventory (PSI) based on sources undergraduate students select for both course‐related and everyday‐life information‐seeking purposes. Also considered are differences in self‐efficacy, intolerance of uncertainty, and external locus of control scores reliant upon sources selected initially during a search process. Two main research questions were the focus of this study. First, what types of information sources do undergraduates tend to use first during an everyday‐life or course‐related search, and is context important? Second, do certain user characteristics influence the selection of the first source selected during information searches? A series of chi square and one tailed t tests were performed to examine these research questions in depth. The overarching goal of this research is to use these results to better understand and structure information services for undergraduates.
Effect of institutional factors on source and channel use by medical residents
Authors: Agarwal Naresh , Xu Yunjie (Calvin) , Lawrence Harrison , Agarwal Archana
Published: January 2013

An important question in information‐seeking behavior is how people decide on which information source to use when they need information for their work‐related tasks. This question becomes especially pertinent in light of the varying degree of legitimacy accorded to digital sources, and the use of new channels of access such as mobiles and tablets. Building upon an earlier study on source use, and using the institutional theory, this is a report of a survey‐in‐progress of medical residents in one or more Boston hospitals. The study will also examine the role of serendipity in source choice when residents encounter information when not consciously looking for it. Insights gained from the study will build on past work on information behavior and source choice, as well as the application of institutional theory to hospital settings. It will help hospitals make optimal provision of information source types based on their preference and usage by medical residents.
A novel research approach to enhance research group‐level science data management
Authors: D'Ignazio John , Qin Jian
Published: January 2013

This poster will report an alternative approach compared with large‐scale collection, technology development, or discipline informatics projects by exploring the enhancement of science data management at the research group level. An academic‐year‐long project involving both information and technical analysts demonstrated that flexible introduction of IT in the form of a relational database solution presents an opportunity to incorporate data‐related practices, behavior, and schemes into a tool. The project team used cognitive work analysis and participatory design research methods to sensitively analyze research practice and then design and introduce a prototype tool. Iterative analysis and design cycles captured and incorporated the complex practices of researchers who struggle with the accumulation of samples and related digital data files from years of research. Design research processes will be analyzed according to project developments and research group reaction to the proposed data management tool design and preliminary attempt at implementation.
Accuracy of National Stereotypes in Central Europe: Outgroups are not Better than Ingroup in considering Personality Traits of Real People
Authors: HŘebÍČková Martina , Graf Sylvie
Published: January 2013

In a study on national stereotypes in central Europe—composed of Austria, the Czech Republic, Germany, Poland and Slovakia—2241 participants rated their autostereotype (a typical representative of their own country) and heterostereotypes (typical representatives of the other countries) by using National Character Survey (NCS). Existing data from 17377 participants including self–reports or observer ratings on Revised NEO Personality Inventory and NCS were compared with the national autostereotypes and heterostereotypes. Although national autostereotypes converged with personality traits of real people in Poland and an adult subsample in the Czech Republic, national heterostereotypes did not correspond to personality traits of real people in any of the studied countries. National stereotypes were shared within as well as across countries. In heterostereotypes, raters from similar cultural backgrounds speaking similar languages agreed better as compared with raters from more distant cultures. Target country played a role in agreement of raters from different countries, showed in the highest convergence between autostereotypes and heterostereotypes of a typical German. Sharing of national stereotypes is influenced by political and economic significance of the target country. Although national autostereotypes clearly differentiated between typical representatives of central European countries, the comparison of personality profiles of their inhabitants showed remarkable resemblance. Copyright © 2013 European Association of Personality Psychology.
Technical and economical assessment of voltage control strategies in distribution grids
Authors: Stetz Thomas , Kraiczy Markus , Braun Martin , Schmidt Sebastian
Published: January 2013

Technically effective and economically efficient voltage control is a major issue in distribution systems with high amounts of installed capacity from dispersed generators, such as photovoltaic. In this paper, the results of an encompassing cost–benefit analysis for different voltage control strategies are presented. The investigated voltage control strategies comprise two different reactive power control methods and one combined reactive power/active power control method, each applied by inverters of utility scale photovoltaic systems. The results are gained by performing 12‐month root‐mean‐square simulations with a 1 min resolution, using the model of a real distribution grid as well as complex generation and load models. The simulations show that local reactive power provision methods as well as temporal active power output curtailment methods are capable of reducing the necessity of a voltage‐driven grid reinforcement. However, the economic benefit of those voltage control strategies highly depends on the parameterization of the respective control algorithm. Copyright © 2013 John Wiley & Sons, Ltd.
Toward a “Structural BLAST”: Using structural relationships to infer function
Authors: Dey Fabian , Cliff Zhang Qiangfeng , Petrey Donald , Honig Barry
Published: January 2013

We outline a set of strategies to infer protein function from structure. The overall approach depends on extensive use of homology modeling, the exploitation of a wide range of global and local geometric relationships between protein structures and the use of machine learning techniques. The combination of modeling with broad searches of protein structure space defines a “structural BLAST” approach to infer function with high genomic coverage. Applications are described to the prediction of protein–protein and protein–ligand interactions. In the context of protein–protein interactions, our structure‐based prediction algorithm, PrePPI, has comparable accuracy to high‐throughput experiments. An essential feature of PrePPI involves the use of Bayesian methods to combine structure‐derived information with non‐structural evidence (e.g. co‐expression) to assign a likelihood for each predicted interaction. This, combined with a structural BLAST approach significantly expands the range of applications of protein structure in the annotation of protein function, including systems level biological applications where it has previously played little role.
Temperature‐dependent conformational change affecting Tyr11 and sweetness loops of brazzein
Authors: Cornilescu Claudia C. , Cornilescu Gabriel , Rao Hongyu , Porter Sarah F. , Tonelli Marco , DeRider Michele L. , Markley John L. , Assadi‐Porter Fariba M.
Published: January 2013

The sweet protein brazzein, a member of the Csβα fold family, contains four disulfide bonds that lend a high degree of thermal and pH stability to its structure. Nevertheless, a variable temperature study has revealed that the protein undergoes a local, reversible conformational change between 37 and 3°C with a midpoint about 27°C that changes the orientations and side‐chain hydrogen bond partners of Tyr8 and Tyr11. To test the functional significance of this effect, we used NMR saturation transfer to investigate the interaction between brazzein and the amino terminal domain of the sweet receptor subunit T1R2; the results showed a stronger interaction at 7°C than at 37°C. Thus the low temperature conformation, which alters the orientations of two loops known to be critical for the sweetness of brazzein, may represent the bound state of brazzein in the complex with the human sweet receptor. Proteins 2013; © 2012 Wiley Periodicals, Inc.
Authentication with low‐cost RFID tags in mobile networks
Authors: Yen Chih‐Ta , Guo Ming‐Huang , Lo Nai‐Wei , Deng Der‐Jiunn
Published: January 2013

Recently, mobile networks and radio frequency identification (RFID) technologies are both widely applied by many enterprises to develop their applications. The third‐generation (3G) mobile network technology is one of the popular mobile network technologies because service providers can serve users anytime and anywhere through 3G mobile network technology. A solution that combines RFID technology with 3G mobile network technology could identify users anytime and anywhere. However, RFID tags are limited in computation power and suffered from security threats, especially on mobile networks. An authentication with low‐cost RFID tags in Mobile Networks should be proposed in this paper. This paper designs a key agreement mechanism to achieve consistency, integration, legality, and safety. In order to design a low‐cost scheme, our authentication mechanism is built of simple XOR operations and one‐way hash function. Although the computation cost of our proposed mechanism is not the best, our proposed mechanism can achieve more security requirements for practical applications. Copyright © 2013 John Wiley & Sons, Ltd.
Software firm turnarounds in the 1990s: An analysis of reversing decline in a growing, dynamic industry
Authors: Ndofor Hermann Achidi , Vanevenhoven Jeff , Barker Vincent L.
Published: January 2013

Investigations into management actions that reverse organizational decline have produced inconsistent findings. Prior studies have focused on the value of retrenchment actions versus strategic actions to engineer a performance turnaround. These studies, however, have generally not controlled for the cause of firm decline, overlooking a major theoretical contingency. Examining prepackaged software firms in the 1990s, we test the association of strategic and retrenchment actions in facilitating turnarounds in a munificent industry. The results show that measures of strategic actions—new product introductions, strategic alliances, and acquisitions—were positively associated with turnarounds. Conversely, measures of retrenchment actions—layoffs, asset reductions, and product withdrawals—were negatively associated with performance recovery. Our results suggest declining firms in munificent industries cannot retrench their way back to prosperity. Copyright © 2013 John Wiley & Sons, Ltd.
Product and environmental social performance: Varying effect on firm performance
Authors: Jayachandran Satish , Kalaignanam Kartik , Eilert Meike
Published: January 2013

Corporate social performance (CSP) consists of actions in different domains that vary in the information they provide stakeholders, and hence, in their effect on firm performance. To demonstrate this, the authors examine the impact of CSP on firm performance in two areas—the product and the environment, referred to as product social performance (PSP) and environmental social performance (ESP), respectively. PSP has a stronger positive impact on firm performance compared to ESP. The findings using disaggregated measures of PSP and ESP indicate negativity bias in that PSP weakness has a stronger negative impact on firm performance compared to PSP strength. Copyright © 2013 John Wiley & Sons, Ltd.
Computational analysis of associations between alternative splicing and histone modifications
Authors: Shindo Yuki , Nozaki Tadasu , Saito Rintaro , Tomita Masaru
Published: January 2013

Pre‐mRNA splicing is a complex process involving combinatorial effects of cis‐ and trans‐elements. Here, we focused on histone modifications as typical trans‐regulatory elements and performed systematic analyses of associations between splicing patterns and histone modifications by using publicly available ChIP‐Seq, mRNA‐Seq, and exon‐array data obtained in two human cell lines. We found that several types of histone modifications including H3K36me3 were associated with the inclusion or exclusion of alternative exons. Furthermore, we observed that the levels of H3K36me3 and H3K79me1 in the cell lines were well correlated with the differences in alternative splicing patterns between the cell lines.
Promoting historical thinking using the explicit reasoning text
Authors: Lee Mimi
Published: January 2013

Current trends in history education emphasize using disciplined inquiry to teach history. Scholars and teachers promote historical thinking as a classroom practice, arguing that teachers should help students “do history.” However, history textbooks, which are the most widely used instructional material in history classrooms, stand in sharp contrast to the emphasis on historical inquiry because of the use of an omniscient voice and a didactic tone that is characteristic of the genre. This study reconsiders the value of textbook narratives as vehicles to promote and encourage historical thinking and suggests an innovative way of developing texts that would serve the instructional purpose of improving students’ historical thinking. Drawing from the scholarship on considerate and voiced texts, this study presents a new model for textbook narrative that embeds historians’ reasoning into the narrative, Explicit Reasoning Text (ERT). Based on interviews with 12 high school students, this study argues the effectiveness of the ERT to engage students in historical investigation.
Conodonts from the Niur Formation (Silurian) of the Derenjal Mountains, Central Iran
Authors: MÄNNIK P. , MILLER C. G. , HAIRAPETIAN V.
Published: January 2013

A Llandovery to Ludlow age for the Niur Formation in the Derenjal Mountains (east-central Iran) is proposed based on new conodont data and previous work on other fossils. The uppermost part of the studied section yielded no diagnostic conodonts but may be Pridoli in age. Some intervals can be dated more precisely: Unit 11 (at least its upper part) is middle Telychian in age and corresponds to thePterospathodus amorphognathoides lennartiZone; the lowermost part of Unit 16 is earliest Ludlow in age and corresponds to theKockelella crassaZone; the uppermost Unit 16 is late Ludlow (Ludfordian) in age and corresponds to theOzarkodina snajdriInterval Zone. The Llandovery–Wenlock boundary lies between units 12 and 13 based on sedimentological evidence. The precise location of the Wenlock–Ludlow boundary in the section is not clear but lies below Unit 16. Present-day Iran was located far away from Baltica and Laurentia, on the other side of the Rheic Ocean. This ocean does not seem to have been a major migration barrier for most organisms including the conodonts.
Maternal filarial infection: association of anti-sheath antibody responses with plasma levels of IFN-γand IL-10
Authors: ACHARY K. G. , MANDAL N. N. , MISHRA S. , SARANGI S. S. , KAR S. K. , SATAPATHY A. K. , BAL M. S.
Published: January 2013

Maternal filarial infection influences the risk of acquiring infection and development of immunity in children. Here we have analysed the blood samples of 60 mothers (24 infected and 36 uninfected) and their corresponding cord bloods to assess the impact of maternal infection on the anti-sheath antibodies and cytokine production in neonates born from them. About 69·4% of non-infected mothers and their cord bloods showed the presence of anti-sheath antibodies, while only 16·6% of the cord bloods from infected mothers were positive for it. The IL-10 level was significantly high in cord bloods of infected mothers compared with non-infected mothers. At the same time the IL-10 level was also observed to be remarkably high in cord bloods of both infected and non-infected mothers negative for anti-sheath antibody. In contrast, IFN-γlevels were significantly high in cord bloods of non-infected mothers compared with infected mothers and the increment was prominent in cord bloods of both infected and non-infected mothers positive for anti-sheath antibody. The study reveals that the presence or absence of anti-sheath antibodies in association with cytokines skews the filarial specific immunity to either Th1 or Th2 responses in neonates. This may affect the natural history of filarial infection in early childhood.
Procedures without borders: The language-ideological anchorage of legal-administrative procedures in translocal institutional settings
Authors: Maryns Katrijn
Published: January 2013

Theoretical and applied research in the field of institutional discourse analysis calls for an increasing awareness of the constitutive nature of discourse in the representation and the assessment of social identities (Sarangi & Roberts 1999; Blommaert 2010; Eades 2010). The staunchly textualist accounts surviving institutional practice, however, tend to obscure complex multidiscursive and language ideologically anchored processes that mold procedural outcomes. On the basis of first-hand ethnographic data collected across legal-administrative procedures in Belgium, this article aims at revealing some meaningful contexts that have been erased in the case of an asylum seeker who became a murder victim and whose asylum file was used in the assize trial as a resource to sketch his social identity. The analysis explores the ideological functioning of textuality in the situated details of communicative practice, thereby aiming for a better understanding of the intricacies of multidiscursive identity construction in translocal procedural settings. (Institutional discourse analysis, multidiscursivity, language ideology and identity, sociolinguistic mobility, asylum procedure, assize court procedure)*
Low-income Housing in Chinese Cities: Policies and Practices
Authors: Huang Youqin
Published: January 2013

This paper argues that the low-income housing programme in China has so far failed to provide adequate housing for the poor for three main reasons: the central government's failure to define a clear mission; a lack of commitment from local governments; and an exclusionary policy towards migrants. A systematic review of low-income housing policy in China shows that the central government juggles its economic and socio-political goals thereby causing constant changes in low-income housing policy. Meanwhile, the existing public finance system, the performance evaluation system and localization in policy implementation have all resulted in a lack of commitment from local governments to low-income housing. Inadequate provision is made worse by problems with allocation. Despite encouraging changes since 2010, many factors underlying the government's failures remain unchanged, thus the fate of low-income housing remains uncertain.
Neglected infectious diseases: Are push and pull incentive mechanisms suitable for promoting drug development research?
Authors: Mueller-Langer Frank
Published: January 2013

Infectious diseases are among the main causes of death and disability in developing countries, and they are a major reason for the health disparity between rich and poor countries. One of the reasons for this public health tragedy is a lack of lifesaving essential medicines, which either do not exist or badly need improvements. In this article, we analyse which of the push and pull mechanisms proposed in the recent literature may serve to promote research into neglected infectious diseases. A combination of push programmes that subsidise research inputs through direct funding and pull programmes that reward research output rather than research input may be the appropriate strategy to stimulate research into neglected diseases. On the one hand, early-stage (basic) research should be supported through push mechanisms, such as research grants or publicly financed research institutions. On the other hand, pull mechanisms, such as prize funds that link reward payments to the health impacts of effective medicines, have the potential to stimulate research into neglected diseases.
Effect of plasma N2 and thermal NH3 nitridation in HfO2 for ultrathin equivalent oxide thickness
Authors: Dai Min , Wang Yanfeng , Shepard Joseph , Liu Jinping , Brodsky Maryjane , Siddiqui Shahab , Ronsheim Paul , Ioannou Dimitris P , Reddy Chandra , Henson William , Krishnan Siddarth , Narayanan Vijay , Chudzik Michael P
Published: January 2013

Two methods of HfO2 nitridation including plasma N2 nitridation and thermal NH3 anneal were studied for ultrathin HfO2 gate dielectrics with <1 nm equivalent oxide thickness (EOT). The detailed nitridation mechanism, nitrogen depth profile, and nitrogen behavior during the anneal process were thoroughly investigated by XPS and SIMS analysis for the two types of nitridation processes at different process conditions. Intermediate metastable nitrogen was observed and found to be important during the plasma nitridation process. For thermal NH3 nitridation, pressure was found to be most critical to control the nitrogen profile while process time and temperature produced second order effects. The physical analyses on the impacts of various process conditions are well correlated to the electrical properties of the films, such as leakage current, EOT, mobility, and transistor bias temperature instability.
On the magnetic field signal radiated by an atmospheric pressure room temperature plasma jet
Authors: Wu S. , Huang Q. , Wang Z. , Lu X.
Published: January 2013

In this paper, the magnetic field signal radiated from an atmospheric pressure room temperature plasma plume is measured. It's found that the magnetic field signal has similar waveform as the current carried by the plasma plume. By calibration of the magnetic field signal, the plasma plume current is obtained by measuring the magnetic field signal radiated by the plasma plume. In addition, it is found that, when gas flow modes changes from laminar regime to turbulence regime, the magnetic field signal waveforms appears different, it changes from a smooth curve to a curve with multiple spikes. Furthermore, it is confirmed that the plasma plume generated by a single electrode (without ground electrode) plasma jet device carries higher current than that with ground electrode.
Comprehensive study of the metal-insulator transition in pulsed laser deposited epitaxial VO2 thin films
Authors: Fu Deyi , Liu Kai , Tao Tao , Lo Kelvin , Cheng Chun , Liu Bin , Zhang Rong , Bechtel Hans A. , Wu Junqiao
Published: January 2013

In this paper, we present a comprehensive, correlative study of the structural, transport, optical and thermoelectric properties of high-quality VO2 thin films across its metal-insulator phase transition. Detailed x-ray diffraction study shows that it's textured polycrystalline along [010]M1, with in-plane lattice orienting along three equivalent crystallographic directions. Across the metal-insulator transition, the conductivity increases by more than 3 orders of magnitude with a value of 3.8 × 103 S/cm in the metallic phase. This increase is almost entirely accounted for by a change in electron density, while the electron mobility changes only slightly between the two phases, yet shows strong domain boundary scattering when the two phases coexist. Electron effective mass was determined to be ∼65m0 in the insulating phase. From the optical and infrared reflection spectra in the metallic phase, we obtained the plasma edge of VO2, from which the electron effective mass was determined to be ∼23m0. The bandgap of VO2 was determined from optical absorption to be 0.70 ± 0.05 eV at room temperature and rapidly shrinks before the phase transition occurs. In the temperature range where metallic and insulating phases coexist, the Seebeck coefficient was found to be significantly lower than that predicted by a linear combination of volumetric contributions from the insulating and metallic domains, indicating abnormal thermoelectric effect at the metal/insulator domain walls in such two-dimensional domain structure.
Strain-induced enhancement of coercivity in amorphous TbFeCo films
Authors: Anuniwat Nattawut , Ding Manli , Poon S. J. , Wolf S. A. , Lu Jiwei
Published: January 2013

We report a strong size dependence of coercivity in amorphous ferrimagnetic TbFeCo films. The as-deposited film exhibited a low saturation magnetization (MS ∼ 100 emu/cc) and a high perpendicular anisotropy (KU ∼ 106 erg/cc). Hall-bar devices were fabricated for characterizing the magneto-transport behaviors. A significant increase in coercivity (up to ∼300%) was observed at room temperature as the width of Hall bar was reduced. The large coercivity enhancement was attributed to the relaxation of film stress. The effect of strain and dimensionality on the coercivity in TbFeCo makes it attractive for tunable coercivity and the magnetization reversal in future nanoscale devices.
Impacts of length and geometry deformation on thermal conductivity of graphene nanoribbons
Authors: Yu ChenXi , Zhang Gang
Published: January 2013

In this work, we report a theoretical study on thermal conductivity of graphene nanoribbons by using molecular dynamics simulation. It is found that the thermal conductivity (κ) increases with the length (L) as, κ∝Lβ, even when the length is up to 600 nm. Moreover, thermal conductivities of curling and twisted graphene nanoribbons are investigated. In contrast to the obvious dependence on sample length, thermal conductivity is not sensitive to these types of geometry deformation due to the superior flexibility of graphenes. Our results predict that curling graphene nanoribbons may have advantages in suspended single-layer heat dissipation devices.
Effect of NH3 plasma treatment on the interfacial property between ultrathin HfO2 and strained Si0.65Ge0.35 substrate
Authors: Yu T. , Jin C. G. , Yang Y. , Zhuge L. J. , Wu X. M. , Wu Z. F.
Published: January 2013

The effect of NH3 plasma treatment on the interfacial property between ultrathin HfO2 and strained Si0.65Ge0.35 substrate has been investigated by high-resolution cross-sectional transmission electron micrographs, x-ray photoelectron spectroscopy, VBS, capacitance-voltage (C-V), and current density-voltage (J-V). TEM and XPS results confirm that interfacial layer with N–Hf and N–Si/O-N-Si bonds acts as a barrier layer against interdiffusions during annealing in some degree. The valence-band offsets ΔEV of HfO2/SiGe interfaces with and without nitridation are determined to be 3.02 ± 0.05 eV and 2.91 ± 0.05, respectively while the conduction-band offsets ΔEC are found to be 1.79 ± 0.05 and 1.90 ± 0.05 eV. The largest total dielectric constant (k) of 15.0 and smallest equivalent oxide thickness of 0.78 nm has been calculated from the accumulation capacitance of the capacitor with NH3 nitridation before post-deposition annealing (PDA). Moreover, the nitrided capacitor after PDA shows a small C-V hysteresis loop of ∼239 mV and low leakage current density (J) of ∼6.53 × 10−7 A/cm2 at a gate bias of Vg = −2.0 V.
Continual collection and re-separation of circulating tumor cells from blood using multi-stage multi-orifice flow fractionation
Authors: Moon Hui-Sung , Kwon Kiho , Hyun Kyung-A , Seok Sim Tae , Chan Park Jae , Lee Jeong-Gun , Jung Hyo-Il
Published: January 2013

Circulating tumor cells (CTCs) are highly correlated with the invasive behavior of cancer; as such, the ability to isolate and quantify CTCs is of great biomedical importance. This research presents a multi-stage multi-orifice flow fractionation (MS-MOFF) device formed by combining three single-stage multi-orifice segments designed for separating breast cancer cells from blood. The structure and dimensions of the MS-MOFF were determined by hydrodynamic principles to have consistent Reynolds numbers (Re) at each multi-orifice segment. From this device, we achieved improved separation efficiency by collecting and re-separating non-selected target cells in comparison with the single-stage multi-orifice flow fractionation (SS-MOFF). The recovery of breast cancer cells increased from 88.8% to greater than 98.9% through the multi-stage multi-orifice segments. This device can be utilized to isolate rare cells from human blood, such as CTCs, in a label-free manner solely through the use of hydrodynamic forces.
Charge transfer in Sr Zintl template on Si(001)
Authors: Choi Miri , Posadas Agham B. , Seo Hosung , Hatch Richard C. , Demkov Alexander A.
Published: January 2013

The formation of the half monolayer (ML) Sr Zintl template layer on Si(001) is investigated in a combined experimental and theoretical work consisting of in situ reflection high energy electron diffraction, in situ x-ray photoelectron spectroscopy (XPS), and density functional theory. Starting with clean 2 × 1 reconstructed Si(001), we demonstrate that Sr deposition leads to a charge transfer from the metal to the Si substrate resulting in the disappearance of the asymmetry of Si dimers—an essential structural change that enables direct perovskite epitaxy on Si, and likely, other semiconductors. XPS reveals an unexpected shift to higher binding energy of the Si 2p core-level components, including the bulk. This unusual behavior is attributed to final state effects using first principles calculations. As measured by ultraviolet photoelectron spectroscopy, the deposition of 0.5 ML of Sr lowers the work function of the system by 1.35 eV, and is in good agreement with our theoretical calculations.
A robust polymer microcable structure for flexible devices
Authors: Kim Eric , Tu Hongen , Lv Cheng , Jiang Hanqing , Yu Hongyu , Xu Yong
Published: January 2013

This letter reports a parylene cable structure that can significantly increase the robustness of flexible devices based on a silicon-island structure. In our previous work, it has been observed that the flexible cables connecting silicon islands could experience stress concentration at the edge of the silicon islands and fracture the metal traces. To address this issue, a micro cushion structure based on parylene micro-channels is proposed to minimize the stress concentration. This structure also improves the overall mechanical strength of the cables, and provides a simple method to encapsulate metal traces reliably.
Piezoresistance of nano-scale silicon up to 2 GPa in tension
Authors: Kumar Bhaskar Umesh , Pardoen Thomas , Passi Vikram , Raskin Jean-Pierre
Published: January 2013

The piezo-resistance of 100 nm-thick, [110] oriented, p-type, mono-crystalline Si beams has been investigated under large uniaxial tension up to 2 GPa using an original on-chip tensile testing set-up. The piezo-resistance coefficient (π) was found to increase by a factor of 6 compared with ∼1.5 for Si bulk, when decreasing the dopant concentration from Na ∼ 1 × 1019 cm−3 down to Na ∼ 5 × 1017 cm−3. Reduction of resistance by a factor of 5.8, higher than theoretical maximum of 4.5, is reported for Na ∼ 5 × 1017 cm−3 under a stress of 1.7 GPa, without any sign of saturation.
Direct electrocaloric measurements of a multilayer capacitor using scanning thermal microscopy and infra-red imaging
Authors: Kar-Narayan S. , Crossley S. , Moya X. , Kovacova V. , Abergel J. , Bontempi A. , Baier N. , Defay E. , Mathur N. D.
Published: January 2013

We present two techniques for directly measuring electrocaloric temperature change in a multilayer capacitor based on BaTiO3. Scanning thermal microscopy with resolution 80 mK, and infra-red imaging with resolution 25 mK, each record electrocaloric temperature changes of ∼0.5 K that match within error. We find that scanning thermal microscopy is more suitable for detecting giant electrocaloric effects in thin films with substrates present.
Probing into the metal-graphene interface by electron transport measurements
Authors: Lin Yen-Fu , Wang Sheng-Tsung , Pao Chia-Chen , Li Ya-Chi , Lai Cheng-Chieh , Lin Chung-Kuan , Hsu Shih-Ying , Jian Wen-Bin
Published: January 2013

Metal-graphene contact recently attracts much attention because of its effects on the performance and the operational speed of graphene field-effect transistor. Simple two-probe graphene devices on mechanically exfoliated graphene flakes are fabricated and the temperature behavior of resistance is measured from room temperature down to liquid helium temperature for the study of electron transport in the interface. Comparing experimental data with several different transport theories, it is confirmed that the model of fluctuation-induced tunneling conduction describes precisely the electron transport and indicates the existence of a thin insulating layer in the metal-graphene interface. Through the interface probing by electron transport measurements, the way to reduce the contact resistance is suggested.
Chaotic quantum transport near the charge neutrality point in inverted type-II InAs/GaSb field-effect transistors
Authors: Pan W. , Klem J. F. , Kim J. K. , Thalakulam M. , Cich M. J. , Lyo S. K.
Published: January 2013

We present here our recent quantum transport results around the charge neutrality point (CNP) in a type-II InAs/GaSb field-effect transistor. At zero magnetic field, a conductance minimum close to 4e2/h develops at the CNP and it follows semi-logarithmic temperature dependence. In quantized magnetic (B) fields and at low temperatures, well developed integer quantum Hall states are observed in the electron as well as hole regimes. Charged carrier (electron and hole) transport shows noisy behavior around the CNP at extremely high B fields. When the diagonal conductivity σxx is plotted against the Hall conductivity σxy, an unexpected conductivity circle law is observed.
Communication: A vibrational study of titanium dioxide cation using the vacuum ultraviolet laser pulsed field ionization-photoelectron method
Authors: Chang Yih-Chung , Huang Huang , Luo Zhihong , Ng C. Y.
Published: January 2013

We have successfully measured the vacuum ultraviolet (VUV) laser photoionization efficiency and pulsed field ionization-photoelectron (PFI-PE) spectra of cold titanium dioxide (TiO2) prepared by a supersonically cooled laser ablation source. The VUV-PFI-PE spectrum thus obtained exhibits long progressions of the v2+(a1) bending and the combination of v1+(a1) stretching and v2+(a1) bending vibrational modes of the TiO2+($\tilde {\rm X}{}^2{\rm B}_2$X̃2B2) ion. The pattern of Franck-Condon factors observed indicates that the O–Ti–O bond angle of the TiO2+($\tilde {\rm X}{}^2{\rm B}_2$X̃2B2) ion is significantly different from that of the TiO2($\tilde {\rm X}{}^1{\rm A}_1$X̃1A1) neutral, whereas the change of the Ti–O bond distance is very minor upon the photoionization transition. The analysis of the PFI-PE bands has made possible the determination of the adiabatic ionization energy for TiO2, IE(TiO2) = 77215.9 ± 1.2 cm−1 (9.57355 ± 0.00015 eV), the harmonic vibrational frequencies, ω1+ = 829.1 ± 2.0 cm−1 and ω2+ = 248.7 ± 0.6 cm−1, and the anharmonic coefficients, χ11+ = 5.57 ± 0.65 cm−1, χ22+ = 0.08 ± 0.06 cm−1, and χ12+ = −4.51 ± 0.30 cm−1 for the TiO2+($\tilde {\rm X}{}^2{\rm B}_2$X̃2B2) ground state.
Rate of hydrolysis in ATP synthase is fine-tuned by α-subunit motif controlling active site conformation
Authors: Beke-Somfai Tamás , Lincoln Per , Nordén Bengt
Published: January 2013

Computer-designed artificial enzymes will require precise understanding of how conformation of active sites may control barrier heights of key transition states, including dependence on structure and dynamics at larger molecular scale. F
o
F
1
ATP synthase is interesting as a model system: a delicate molecular machine synthesizing or hydrolyzing ATP using a rotary motor. Isolated F
1
performs hydrolysis with a rate very sensitive to ATP concentration. Experimental and theoretical results show that, at low ATP concentrations, ATP is slowly hydrolyzed in the so-called tight binding site, whereas at higher concentrations, the binding of additional ATP molecules induces rotation of the central γ-subunit, thereby forcing the site to transform through subtle conformational changes into a loose binding site in which hydrolysis occurs faster. How the 1-Å-scale rearrangements are controlled is not yet fully understood. By a combination of theoretical approaches, we address how large macromolecular rearrangements may manipulate the active site and how the reaction rate changes with active site conformation. Simulations reveal that, in response to γ-subunit position, the active site conformation is fine-tuned mainly by small α-subunit changes. Quantum mechanics-based results confirm that the sub-Ångström gradual changes between tight and loose binding site structures dramatically alter the hydrolysis rate.
Alignment of cellular motility forces with tissue flow as a mechanism for efficient wound healing
Authors: Basan Markus , Elgeti Jens , Hannezo Edouard , Rappel Wouter-Jan , Levine Herbert
Published: January 2013

Recent experiments have shown that spreading epithelial sheets exhibit a long-range coordination of motility forces that leads to a buildup of tension in the tissue, which may enhance cell division and the speed of wound healing. Furthermore, the edges of these epithelial sheets commonly show finger-like protrusions whereas the bulk often displays spontaneous swirls of motile cells. To explain these experimental observations, we propose a simple flocking-type mechanism, in which cells tend to align their motility forces with their velocity. Implementing this idea in a mechanical tissue simulation, the proposed model gives rise to efficient spreading and can explain the experimentally observed long-range alignment of motility forces in highly disordered patterns, as well as the buildup of tensile stress throughout the tissue. Our model also qualitatively reproduces the dependence of swirl size and swirl velocity on cell density reported in experiments and exhibits an undulation instability at the edge of the spreading tissue commonly observed in vivo. Finally, we study the dependence of colony spreading speed on important physical and biological parameters and derive simple scaling relations that show that coordination of motility forces leads to an improvement of the wound healing process for realistic tissue parameters.
Half or more of the somatic mutations in cancers of self-renewing tissues originate prior to tumor initiation
Authors: Tomasetti Cristian , Vogelstein Bert , Parmigiani Giovanni
Published: January 2013

Although it has been hypothesized that some of the somatic mutations found in tumors may occur before tumor initiation, there is little experimental or conceptual data on this topic. To gain insights into this fundamental issue, we formulated a mathematical model for the evolution of somatic mutations in which all relevant phases of a tissue’s history are considered. The model makes the prediction, validated by our empirical findings, that the number of somatic mutations in tumors of self-renewing tissues is positively correlated with the age of the patient at diagnosis. Importantly, our analysis indicates that half or more of the somatic mutations in certain tumors of self-renewing tissues occur before the onset of neoplasia. The model also provides a unique way to estimate the in vivo tissue-specific somatic mutation rates in normal tissues directly from the sequencing data of tumors. Our results have substantial implications for the interpretation of the large number of genome-wide cancer studies now being undertaken.