bluuebunny/crossref_metadata_2025 huggingface dataset:
State Control, Female Prostitution and HIV Prevention in China
Authors: Choi Susanne Y.P.
Published: April 2011

By combining analysis of archival documents and data from 245 sex workers interviewed in south-west China between 2003 and 2007, this article argues that the AIDS crisis has prompted a shift in state discourse about prostitution in China from a victim to a victimizer perspective. Concomitant with this discursive shift is the gradual intensification of control over prostitution. Our data show that the victim perspective overlooks the fact that sex workers are agents who actively negotiate their work and lives amid limited options in post-socialist China. The victimizer perspective, on the other hand, misplaces the blame of unsafe sex practices on sex workers, while in reality it is their clients who refuse to use condoms. The data further suggest that repressive measures against prostitution premised on this victim–victimizer dichotomy inhibit the ability of sex workers to negotiate safe sex practices and aggravate their exposure to HIV risk. The repressive measures undermine the supportive professional networks of sex workers, increase economic pressure on the workers and increase their exposure to client-perpetrated violence.
KARL KNIES AND THE PREHISTORY OF NEOCLASSICAL ECONOMICS: UNDERSTANDING THE IMPORTANCE OF “DIE NATIONALOEKONOMISCHE LEHRE VOM WERTH” (1855)
Authors: PAPADOPOULOS KOSMAS , BATEMAN BRADLEY W.
Published: April 2011

This essay serves as the introduction to the authors’ translation of Karl Knies’ essay “Die nationaloekonomische Lehre vom Werth” (1855). Knies is one of the acknowledged founders of the Older German Historical School, and yet in recent years several writers have described his 1855 essay as seminal in the evolution of marginal utility analysis. The authors examine how Knies develops his nascent theory of marginal reasoning in his essay, arguing that rather than cling to his earlier historicist programmatic, Knies attempts to discover general laws; however, not by strict causal analysis but by a typical ‘German art’ of taxonomy and classification that resembles juridical argumentations. This results in an ambiguous text, which influenced several marginalist pioneers who studied under Knies at Heidelberg (including Eugen von Böhm-Bawerk, Friedrich von Wieser, and John Bates Clark), as well as several members of the Younger German Historical School (including Gustav von Schmoller).
Children rule, or do they (as far as innovations are concerned)?
Authors: JOSEPH BRIAN D.
Published: April 2011

Meisel (hereafter, M) has offered a well-argued and tightly structured piece, discussing in a clear and compelling way a crucial topic in the understanding of language change. I applaud him for both the content and the presentation.
Three forms of trust and their association
Authors: Newton Ken , Zmerli Sonja
Published: April 2011

This article investigates the relationships between particular social trust, general social trust, and political trust and tests a variety of political, social-psychological, and social capital theories of them. This sort of research has not been carried out before because until the World Values Survey of 2005–07 there has been, to our knowledge, no comparative survey that includes measures of particular and other forms of trust. The new data challenge a common assumption that particular social trust is either harmful or of little importance in modern democracies and shows that it has strong, positive associations with other forms of trust. However, the relationships are not symmetrical and particular social trust seems to be a necessary but not sufficient cause of general social trust, and both forms of social trust appear to be necessary, but not sufficient conditions for political trust. Strong evidence of mutual associations between different forms of trust at both the individual micro level and the contextual macro level supports theories of rainmaker effects, the importance of political institutions, and the significance of social trust for political trust. In more ways than one, social trust, not least of a particular type, seems to have an important bearing on social and political stability.
Under which conditions does spending on active labor market policies increase? An fsQCA analysis of 53 governments between 1985 and 2003
Authors: Vis Barbara
Published: April 2011

This article examines the conditions under which governments increase spending on active labor market policies (ALMPs), as the European Union and the organization of economic co-operation and development recommend. Given that ALMPs are usually expensive and unlikely to win a government many votes, this study hypothesizes that an improving socio-economic situation is a necessary condition for increased spending. On the basis of the data of 53 governments from 18 established democracies between 1985 and 2003, the fuzzy-set qualitative comparative analysis shows that there are different combinations of conditions, or routes, toward activation and that an improving socio-economic situation is needed for each of them. Specifically, the analysis reveals that governments activate under decreasing unemployment combined with (1) trade openness, or (2) the absence of corporatism in the case of leftist governments, or (3) the presence of corporatism in the case of rightist governments. These findings advance our understanding of the politics of labor market reform.
Globalization and extra-parliamentary politics in an era of democracy
Authors: Arce Moises , Kim Wonik
Published: April 2011

Two currents can be distinguished in the literature regarding the domestic consequences of globalization. One perspective holds that globalization depoliticizes extra-parliamentary protest activity despite the presence of democracy. Another perspective suggests that globalization has contributed to the repoliticization of protest, especially when democracy is present. Using cross-sectional time-series data in a global sample for the 1970–2006 period, the paper examines the effect of globalization on extra-parliamentary protest activity in the context of democracy. The paper further tests these relationships cross-regionally comparing East Asia with Latin America – arguably the two regions in the world where dual transitions to economic and political liberalization have been in full force since 1970s. The results reveal distinct patterns of protest activity cross-regionally, whereby East Asia approximates the depoliticization trend from the global sample. In contrast, the results for Latin America provide confirming evidence for the repoliticization perspective. These findings remain robust across a number of control variables, and different measures of democracy and estimation techniques. Overall, the paper shows that democracy influences the relationship between globalization and extra-parliamentary protest activity – a relationship that up to now has remained systematically untested.
Crafting tolerance: the role of political institutions in a comparative perspective
Authors: Kirchner Antje , Freitag Markus , Rapp Carolin
Published: April 2011

Ongoing changes in social structures, orientation, and value systems confront us with the growing necessity to address and understand transforming patterns of tolerance as well as specific aspects, such as social tolerance. Based on hierarchical analyses of the latest World Values Survey (2005–08) and national statistics for 28 countries, we assess both individual and contextual aspects that influence an individual's perception of different social groupings. Using a social tolerance index that captures personal attitudes toward these groupings, we present an institutional theory of social tolerance. Our results show that specific institutional qualities, which reduce status anxiety, such as inclusiveness, universality, and fairness, prevail over traditional socio-economic, societal, cultural, and democratic explanations.
On the limited interchangeability of rule of law measures
Authors: Møller Jørgen , Skaaning Svend-Erik
Published: April 2011

During the latest decade, empirical research on the causes and consequences of the rule of law has expanded and, in the process, become extremely influential. However, we show that a number of widely used indices of the rule of law are not interchangeable. This lack of interchangeability is reflected in the fact that they are based on different defining attributes, to some extent cover distinct empirical scopes, do not correlate highly with each other, and support different explanatory factors. Until a consensus has been established with respect to the conceptualization of the rule of law, scholars are thus not free to opt for the measure that fits their data requirements best regarding spatial and/or temporal scope. Instead, they must carefully assess the content validity vis-à-vis their stipulated definition of the rule of law. Given the amount of money and time poured into the rule of law agenda, the problems identified reflect the lack of maturity of ‘good governance’ research.
Why it is important to include unpublished data in systematic reviews
Authors: Trespidi C. , Barbui C. , Cipriani A.
Published: April 2011

It is known that studies with statistically significant results have a higher probability to be published (publication bias). Therefore, studies with no statistically significant differences (or not favoring the investigational drug) may not be found in commonly accessed databases and remain unpublished. Moreover, unpublished data may also refer to information that are not included in study reports published in scientific journals but that may be important to estimate study outcomes. Retrieving unpublished evidence represents a compelling challenge for researchers, and in the present paper we explore how to do it.
Secreted factors from brain endothelial cells maintain glioblastoma stem‐like cell expansion through the mTOR pathway
Authors: Galan‐Moya Eva Maria , Le Guelte Armelle , Lima‐Fernandes Evelyne , Thirant Cécile , Dwyer Julie , Bidere Nicolas , Couraud Pierre‐Olivier , Scott Mark G H , Junier Marie‐Pierre , Chneiweiss Hervé , Gavard Julie
Published: April 2011

Glioma stem‐cells are associated with the brain vasculature. However, the way in which this vascular niche regulates stem‐cell renewal and fate remains unclear. Here, we show that factors emanating from brain endothelial cells positively control the expansion of long‐term glioblastoma stem‐like cells. We find that both pharmacological inhibition of and RNA interference with the mammalian target of rapamycin (mTOR) pathway reduce their spheroid growth. Conversely, the endothelial secretome is sufficient to promote this mTOR‐dependent survival. Thus, interfering with endothelial signals might present opportunities to identify treatments that selectively target malignant stem‐cell niches.
APOBEC3A can activate the DNA damage response and cause cell‐cycle arrest
Authors: Landry Sébastien , Narvaiza Iñigo , Linfesty Daniel C , Weitzman Matthew D
Published: April 2011

Human apolipoprotein‐B mRNA‐editing catalytic polypeptide‐like 3 (APOBEC3) proteins constitute a family of cytidine deaminases that mediate restriction of retroviruses, endogenous retro‐elements and DNA viruses. It is well established that these enzymes are potent mutators of viral DNA, but it is unclear whether their editing activity is a threat to the integrity of the cellular genome. We show that expression of APOBEC3A can lead to induction of DNA breaks and activation of damage responses in a deaminase‐dependent manner. Consistent with these observations, APOBEC3A expression induces cell‐cycle arrest. These results indicate that cellular DNA is vulnerable to APOBEC3 activity and deregulated expression of APOBEC3A could threaten genomic integrity.
Ribosome degradation in growing bacteria
Authors: Piir Kerli , Paier Anton , Liiv Aivar , Tenson Tanel , Maiväli Ülo
Published: April 2011

Ribosomes are large ribozymes that synthesize all cellular proteins. As protein synthesis is rate‐limiting for bacterial growth and ribosomes can comprise a large portion of the cellular mass, elucidation of ribosomal turnover is important to the understanding of cellular physiology. Although ribosomes are widely believed to be stable in growing cells, this has never been rigorously tested, owing to the lack of a suitable experimental system in commonly used bacterial model organisms. Here, we develop an experimental system to directly measure ribosomal stability in Escherichia coli. We show that (i) ribosomes are stable when cells are grown at a constant rate in the exponential phase; (ii) more than half of the ribosomes made during exponential growth are degraded during slowing of culture growth preceding the entry into stationary phase; and (iii) ribosomes are stable for many hours in the stationary phase. Ribosome degradation occurs in growing cultures that contain almost no dead cells and coincides with a reduction of comparable magnitude in the cellular RNA concentration.
Enhancement of latent fingermarks on non-porous surfaces using anti-l-amino acidantibodies conjugated to gold nanoparticles
Authors: Spindler Xanthe , Hofstetter Oliver , McDonagh Andrew M. , Roux Claude , Lennard Chris
Published: April 2011

This anti-l-amino acid antibody system can enhance aged eccrine-rich latent fingermarks on non-porous surfaces, an area unexploited by current techniques.
Copper-catalyzed cascade synthesis of benzimidazoquinazoline derivatives under mild condition
Authors: Xu Shan , Lu Juyou , Fu Hua
Published: April 2011

An efficient copper-catalyzed cascade method has been developed for the synthesis of benzimidazoquinazoline derivatives via reactions of readily available substituted 2-(2-halophenyl)benzoimidazoles with amidines or guanidine under mild conditions (even at room temperature).
Evidence-Based Practice for Children With Speech Sound Disorders: Part 2 Application to Clinical Practice
Authors: Baker Elise , McLeod Sharynne
Published: April 2011

Purpose

This article provides both a tutorial and a clinical example of how speech-language pathologists (SLPs) can conduct evidence-based practice (EBP) when working with children with speech sound disorders (SSDs). It is a companion paper to the narrative review of 134 intervention studies for children who have an SSD (Baker & McLeod, 2011).

Method

A seven-step EBP decision-making process is presented for managing SSDs in children (drawing on the work of Dollaghan, 2007, and Gillam & Gillam, 2006). We describe how SLPs can integrate externally published evidence with evidence from clinical practice as well as client factors, values, and preferences, to make clinical decisions. An organized EBP network is described as a clinical example of the application of the EBP decision-making process.

Results

Compared with a matched and national sample, SLPs in the EBP network were more likely to read relevant articles and tended to have more confidence in research evidence and in their own ability to select intervention targets based on published research.

Conclusion

SLPs need to use their clinical expertise to integrate research findings with the constraints and complexities of everyday clinical practice and client factors, values, and preferences in their management of SSDs in children.
Creative and Stylistic Devices Employed by Children During a Storybook Narrative Task: A Cross-Cultural Study
Authors: Gorman Brenda K. , Fiestas Christine E. , Peña Elizabeth D. , Clark Maya Reynolds
Published: April 2011

Purpose

The purpose of this study was to analyze the effects of culture on the creative and stylistic features children employ when producing narratives based on wordless picture books.

Method

Participants included 60 first- and second-grade African American, Latino American, and Caucasian children. A subset of narratives based on wordless picture books collected as part of a larger study was coded and analyzed for the following creative and stylistic conventions: organizational style (topic centered, linear, cyclical), dialogue (direct, indirect), reference to character relationships (nature, naming, conduct), embellishment (fantasy, suspense, conflict), and paralinguistic devices (expressive sounds, exclamatory utterances).

Results

Many similarities and differences between ethnic groups were found. No significant differences were found between ethnic groups in organizational style or use of paralinguistic devices. African American children included more fantasy in their stories, Latino children named their characters more often, and Caucasian children made more references to the nature of character relationships.

Conclusion

Even within the context of a highly structured narrative task based on wordless picture books, culture influences children’s production of narratives. Enhanced understanding of narrative structure, creativity, and style is necessary to provide ecologically valid narrative assessment and intervention for children from diverse cultural backgrounds.
Survey of K–3rd-Grade Teachers' Knowledge of Ear Infections and Willingness to Participate in Prevention Programs
Authors: Danhauer Jeffrey L. , Johnson Carole E. , Caudle Abby T.
Published: April 2011

Purpose

Ear infections are prevalent in kindergarten through 3rd-grade (K–3rd) children and can affect their performance at school. Chewing gum, when administered by parents and teachers, can help prevent ear infections in children. This pilot study surveyed K–3rd-grade teachers in the Santa Barbara School Districts to assess their knowledge about ear infections and their willingness to participate in ear infection prevention programs.

Method

A 37-item questionnaire was developed and was e-mailed to a convenience sample of 112 teachers in February 2010.

Results

Response rate was 26%; 29 teachers responded. Most respondents were experienced females ≥36 years of age who said that their education provided no information about ear infections. Less than half said that they knew signs of ear infections or that ear infections could be prevented, but more than half believed that ear infections could hinder children’s development and quality of life. All of the schools and almost all of the teachers did not permit chewing gum on campus or in their classrooms, but most teachers said they would participate in ear infection prevention programs, let students chew xylitol gum if it prevented ear infections, and wanted more information on this topic.

Conclusion

Although teachers said they would participate in ear infection prevention programs, obstacles were identified that could preclude the use of xylitol chewing gum. Prevention programs should be developed, but xylitol gum prophylaxis regimens may be better directed at in-home use.
Dysphagia Management: A Survey of School-Based Speech-Language Pathologists in Vermont
Authors: Hutchins Tiffany L. , Gerety Katherine W. , Mulligan Moira
Published: April 2011

Purpose

This study (a) gathered information about the kinds of dysphagia management services school-based speech-language pathologists (SLPs) provide, (b) examined the attitudes of SLPs related to dysphagia management, (c) compared the responses of SLPs on the basis of their experience working in a medical setting, and (d) investigated the relationship between SLPs' training and their confidence to provide dysphagia services.

Method

Fifty-two school-based SLPs practicing in Vermont responded to a survey designed to gather information on the variables of interest.

Results

Respondents reported a low incidence of students requiring dysphagia services and SLPs providing a wide range of dysphagia services. Results indicated variability in attitudes related to dysphagia management, but trends were also evident. Chief among them were SLPs' low levels of confidence to provide dysphagia services and the need for additional training in dysphagia management. SLPs who had experience in a medical setting reported greater confidence to evaluate and treat students with dysphagia compared to those without experience in a medical setting. Relationships between a variety of previous training experiences and confidence to treat dysphagia were also revealed.

Conclusion

This study expanded previous research in this area. Factors accounting for our results, limitations, directions for future research, and implications for practice are discussed.
Soft magnetic tweezers: A proof of principle
Authors: Mosconi Francesco , Allemand Jean François , Croquette Vincent
Published: April 2011

We present here the principle of soft magnetic tweezers which improve the traditional magnetic tweezers allowing the simultaneous application and measurement of an arbitrary torque to a deoxyribonucleic acid (DNA) molecule. They take advantage of a nonlinear coupling regime that appears when a fast rotating magnetic field is applied to a superparamagnetic bead immersed in a viscous fluid. In this work, we present the development of the technique and we compare it with other techniques capable of measuring the torque applied to the DNA molecule. In this proof of principle, we use standard electromagnets to achieve our experiments. Despite technical difficulties related to the present implementation of these electromagnets, the agreement of measurements with previous experiments is remarkable. Finally, we propose a simple way to modify the experimental design of electromagnets that should bring the performances of the device to a competitive level.
Evolutionary games defined at the network mesoscale: The Public Goods game
Authors: Gómez-Gardeñes Jesús , Romance Miguel , Criado Regino , Vilone Daniele , Sánchez Angel
Published: April 2011

The evolutionary dynamics of the Public Goods game addresses the emergence of cooperation within groups of individuals. However, the Public Goods game on large populations of interconnected individuals has been usually modeled without any knowledge about their group structure. In this paper, by focusing on collaboration networks, we show that it is possible to include the mesoscopic information about the structure of the real groups by means of a bipartite graph. We compare the results with the projected (coauthor) and the original bipartite graphs and show that cooperation is enhanced by the mesoscopic structure contained. We conclude by analyzing the influence of the size of the groups in the evolutionary success of cooperation.
Complex network analysis of water distribution systems
Authors: Yazdani Alireza , Jeffrey Paul
Published: April 2011

This paper explores a variety of strategies for understanding the formation, structure, efficiency, and vulnerability of water distribution networks. Water supply systems are studied as spatially organized networks for which the practical applications of abstract evaluation methods are critically evaluated. Empirical data from benchmark networks are used to study the interplay between network structure and operational efficiency, reliability, and robustness. Structural measurements are undertaken to quantify properties such as redundancy and optimal-connectivity, herein proposed as constraints in network design optimization problems. The role of the supply demand structure toward system efficiency is studied, and an assessment of the vulnerability to failures based on the disconnection of nodes from the source(s) is undertaken. The absence of conventional degree-based hubs (observed through uncorrelated nonheterogeneous sparse topologies) prompts an alternative approach to studying structural vulnerability based on the identification of network cut-sets and optimal-connectivity invariants. A discussion on the scope, limitations, and possible future directions of this research is provided.
Transition boundary model of magnetization distribution in high density perpendicular recording
Authors: Liu Z. J. , Chen B. J. , Wang H. T.
Published: April 2011

A model is introduced in this paper to describe the transition boundaries in perpendicular magnetic recording at extremely high density. In contrary to the previous signal generation models, effects of magnetization transition curvature and the track edge fluctuations are adequately included in the new model that is designed to capture the actual transition boundaries, i.e., the variations of magnetization distribution in both down-track and across-track directions. The model is used to predict the readback waveforms based on the detailed information obtained from micromagnetic simulations taking into account the head and media parameters. The model is therefore suitable for magnetic recording at extremely high densities when the impact of the transition curvature and the track edge effect on the recording performance becomes more significant.
Biomimetic micro/nanostructured functional surfaces for microfluidic and tissue engineering applications
Authors: Stratakis E. , Ranella A. , Fotakis C.
Published: April 2011

This paper reviews our work on the application of ultrafast pulsed laser micro/nanoprocessing for the three-dimensional (3D) biomimetic modification of materials surfaces. It is shown that the artificial surfaces obtained by femtosecond-laser processing of Si in reactive gas atmosphere exhibit roughness at both micro- and nanoscales that mimics the hierarchical morphology of natural surfaces. Along with the spatial control of the topology, defining surface chemistry provides materials exhibiting notable wetting characteristics which are potentially useful for open microfluidic applications. Depending on the functional coating deposited on the laser patterned 3D structures, we can achieve artificial surfaces that are (a) of extremely low surface energy, thus water-repellent and self-cleaned, and (b) responsive, i.e., showing the ability to change their surface energy in response to different external stimuli such as light, electric field, and pH. Moreover, the behavior of different kinds of cells cultured on laser engineered substrates of various wettabilities was investigated. Experiments showed that it is possible to preferentially tune cell adhesion and growth through choosing proper combinations of surface topography and chemistry. It is concluded that the laser textured 3D micro/nano-Si surfaces with controllability of roughness ratio and surface chemistry can advantageously serve as a novel means to elucidate the 3D cell-scaffold interactions for tissue engineering applications.
A balanced composite backward and forward compact waveguide based on resonant metamaterials
Authors: Tang Qi , Meng Fan-Yi , Wu Qun , Lee Jong-Chul
Published: April 2011

A balanced composite backward and forward waveguide is presented by using modified split ring resonators. The forbidden band between the forward and backward guided mode is eliminated. Acoaxial feed method is proposed to excite both the forward and backward guided modes. The passband of the proposed structure ranges from 4.28GHz to 6.83GHz, below the cutoff frequency of the fundamental mode of the hollow waveguide (∼15 GHz). Physical size of the waveguide has been dramatically decreased.
Convection-enhanced water evaporation
Authors: Weon B. M. , Je J. H. , Poulard C.
Published: April 2011

Water vapor is lighter than air; this can enhance water evaporation by triggering vapor convection but there is little evidence. We directly visualize evaporation of nanoliter (2 to 700 nL) water droplets resting on silicon wafer in calm air using a high-resolution dual X-ray imaging method. Temporal evolutions of contact radius and contact angle reveal that evaporation rate linearly changes with surface area, indicating convective (instead of diffusive) evaporation in nanoliter water droplets. This suggests that convection of water vapor would enhance water evaporation at nanoliter scales, for instance, on microdroplets or inside nanochannels.
A comparison of two methods for modeling large-scale data from time series as complex networks
Authors: Li Ying , Cao Hongduo , Tan Yong
Published: April 2011

In this paper, we compare two methods of mapping time series data to complex networks based on correlation coefficient and distance, respectively. These methods make use of two different physical aspects of large-scale data. We find that the method based on correlation coefficient cannot distinguish the randomness of a chaotic series from a purely random series, and it cannot express the certainty of chaos. The method based on distance can express the certainty of a chaotic series and can distinguish a chaotic series from a random series easily. Therefore, the distance method can be helpful in analyzing chaotic systems and random systems. We have also discussed the effectiveness of the distance method with noisy data.
Atomic site sensitivity of the energy loss magnetic chiral dichroic spectra of complex oxides
Authors: Calmels L. , Rusz J.
Published: April 2011

The quantitative analysis of magnetic oxide core level spectra can become complicated when the magnetic atoms are located at several nonequivalent atomic sites in the crystal. This is, for instance, the case for Fe atoms in magnetite, which are located in tetrahedral and octahedral atomic sites; in this case, the x-ray magnetic circular dichroic (XMCD) spectra recorded at the L2,3 edge of Fe contain contributions from the different nonequivalent atomic sites, which unfortunately cannot be separated. Energy loss magnetic chiral dichroic (EMCD) spectra are the transmission electron microscope analogies of the XMCD spectra. One of the important differences between these two techniques of magnetic analysis is that EMCD uses a fast electron beam instead of polarized light. The fast electrons behave like Bloch states in the sample, and the fine structure of the EMCD spectra is strongly influenced by channeling and dynamical diffraction effects. These effects can be adjusted by changing the experimental configuration. We use theoretical calculations, which include dynamical diffraction effects and in which electronic transitions are treated in the atomic multiplet formalism, to show that the relative weight of the Fe atoms in different nonequivalent atomic sites can be changed by a proper choice of the position of the detector and of the magnetite sample orientation and thickness. We conclude that EMCD spectra could be used to isolate the magnetic contribution of atoms in each of the nonequivalent atomic sites, which would not be possible with XMCD techniques.
Repeatability of magnetic-field driven self-assembly of magnetic nanoparticles
Authors: Henderson J. R. , Crawford T. M.
Published: April 2011

We demonstrate 27 ± 11 nm precision using stray magnetic fields from hard disk drive media to assemble 13 nm Fe3O4 magnetic nanoparticles in de-ionized water. By aligning the substrate polishing striations found in atomic force microscopy (AFM) images of the media topography, we determine the variance of multiple nanoparticle coatings. The widths of the assembled features are ∼200 nm, and features are always distinct when separated by a median distance of 500 nm. As these nanoparticles predictably follow the field gradient, trapped nanoparticles offer a nanoscale precision metrology for mapping the stray magnetic fields of high density media using AFM. Thus our approach offers a means to verify magnetic force microscopy images, as well as a method for nanomanufacturing complex nanoparticle assemblies.
Effect of duty ratio of patterned surface on planarization by gas cluster ion beams
Authors: Nagato Keisuke , Toyoda Noriaki , Naito Hiroki , Tani Hiroshi , Sakane Yasuo , Yamada Isao , Nakao Masayuki , Hamaguchi Tetsuya
Published: April 2011

We studied the effect of the duty ratio, i.e., the ratio of hill width to pitch, of patterned diamondlike carbon (DLC) surfaces on Ar gas cluster ion beam (GCIB) planarization effect. The patterns of 40 nm depth were fabricated on Si substrates by electron beam lithography and CHF3 reactive-ion etching. The pitch of the line-and-space pattern was 300 nm and three duty ratios were adopted. Then, refilling materials were deposited to 50 nm thickness on the patterned substrates. The test samples were irradiated by Ar-GCIB and the resultant surface profiles were measured by atomic force microscopy. The acceleration energy for one cluster was 20 keV. The dose was set in the range from 5×1014 to 5×1016 ion/cm2. Although there was a difference in the dose, the patterns clearly disappeared upon irradiating GCIB. The reduction rate of the peak-to-valley height decreased as the width of the hill increased. We indicated that GCIB irradiation is effective for the planarization of patterned surfaces with various duty ratios.
Magnetization process analysis using a simplified domain structure model
Authors: Matsuo T.
Published: April 2011

A domain structure model (DSM) is simplified to analytically reveal the basic mechanism of the mesoscopic magnetization process. Magnetic energy components are normalized by the anisotropic energy to compare the influence of individual energy components explicitly. The magnetostatic field is approximated as the product of averaged magnetization and demagnetizing factors. A simple two-domain model represents the domain wall motion, nucleation-type hysteresis, and magnetization rotation. Magnetization curves obtained by the simplified DSM agree with those given by the periodic micromagnetic simulation. The simplified DSM represents the discontinuous magnetization-state transition observed in a magneto-impedance sensor.
Confined circularly polarized light generated by nano-size aperture for high density all-optical magnetic recording
Authors: Nakagawa Katsuji , Ashizawa Yoshito , Ohnuki Shinichiro , Itoh Akiyoshi , Tsukamoto Arata
Published: April 2011

It is revealed by the finite difference time domain simulation that a cross aperture antenna can create a localized circularly polarized light, 10 nm in diameter, on the surface of a recording medium. The confined circularly polarized light on the surface, however, expands in the recording layer. We eventually find that the newly proposed modified cross aperture in combination with particle medium leads to confinement of a circularly polarized light in the particle. This proposed combination of a surface plasmon antenna/aperture and recording particles is one of the strategies to achieve high speed and high density for all-optical magnetic recording.
Enhancement of uniaxial magnetic anisotropy in Fe thin films grown on GaAs(001) with an MgO underlayer
Authors: Sakshath S. , Bhat S. V. , Anil Kumar P. S. , Sander D. , Kirschner J.
Published: April 2011

The understanding and control of anisotropy in Fe films grown on cubic systems such as GaAs and MgO has been of interest from the point of view of applications in devices. We report magnetic anisotropy studies on Fe/GaAs(001) and Fe/MgO/GaAs(001) prepared by pulsed laser deposition. In Fe/GaAs(001), magneto optical Kerr effect (MOKE) measurements revealed a dominant uniaxial anisotropy for Fe thickness less than 20 monolayers (ML) and this was confirmed by ferromagnetic resonance (FMR) studies. Multiple steps in the hysteresis loops were observed for Fe films of thickness 20 and 25 ML. Whereas, in Fe/MgO/GaAs(001), even at 25 ML of Fe, the uniaxial anisotropy remained dominant. The anisotropy constants obtained from FMR spectra have shown that the relative strength of uniaxial anisotropy is higher as compared to the cubic anisotropy constant in the case of Fe/MgO/GaAs(001).
Low-temperature properties of Ca-doped YbMnO3 multiferroic single crystals
Authors: Abramov N. , Chichkov V. , Lofland S. E. , Mukovskii Y. M.
Published: April 2011

The specific heat cp and magnetization of single crystal hexagonal manganites of the type Yb1−xCaxMnO3 (x = 0, 0.05, and 0.10) were measured in a wide temperature range as a function of magnetic field. Antiferromagnetic ordering of the Mn sublattice occurs at TN = 83 K. Ca doping has surprisingly minimal effect on the magnetic properties. At low temperature (∼3.5 K), all compounds show ferromagnetic (FM) ordering in the basal plane attributed to Yb in site 2a. For low fields applied along the c direction, Yb spin reorientation occurs and FM ordering disappears. cp shows a broad maximum centered at the temperature ∼6 K that is consistent with a Schottky anomaly related to the Zeeman splitting of the Yb moments due to Mn molecular field. In the field of 30 kOe, the re-entrant FM transition takes place with Yb ions in sites 2a and 4b.
Effect of erythrocytes oscillations on dielectric properties of human diabetic-blood
Authors: Abdalla S.
Published: April 2011

It has been demonstrated that the erythrocytes (RBCs) oscillate during their tank-treading motion with high-frequency oscillations. This oscillatory motion drastically affects the dielectric and electrical properties of RBCs. Moreover, the glucose level in blood affects the electrical and dielectric properties of blood. It has been, also, shown that the frequency of these oscillations exponentially decrease from 1.2 MHz down to 0.85 MHz with variation of glucose level from 85 mg/dL up to 346.1 mg/dL. It is expected that these oscillations strongly affect the general physiological properties of blood and would stimulate the curiosity of scientists and bioengineers to present new, more efficient, rapid, safe and viable diagnostic and/or therapeutic methods for blood disorders; in particular diabetes.
Highly-sensitive chemical detection in the infrared regime using plasmonic gold nanocrosses
Authors: Rodríguez-Fortuño F. J. , Martínez-Marco M. , Tomás-Navarro B. , Ortuño R. , Martí J. , Martínez A. , Rodríguez-Cantó P. J.
Published: April 2011

In this work, we report the design, fabrication, and characterization of gold nanocrosses for chemosensing purposes. The nanocrosses are designed to exhibit a localized surface plasmon resonance which is very sensitive to refractive index changes in the surrounding medium, resulting in sensitivity values of around 500–700 nm per refractive index unit at wavelengths around 1.4 μm. We experimentally demonstrate the functionalization of the gold nanocrosses and the successful sensing of chemical monolayers.
Burst synchronization transitions in a neuronal network of subnetworks
Authors: Sun Xiaojuan , Lei Jinzhi , Perc Matjaž , Kurths Jürgen , Chen Guanrong
Published: April 2011

In this paper, the transitions of burst synchronization are explored in a neuronal network consisting of subnetworks. The studied network is composed of electrically coupled bursting Hindmarsh–Rose neurons. Numerical results show that two types of burst synchronization transitions can be induced not only by the variations of intra- and intercoupling strengths but also by changing the probability of random links between different subnetworks and the number of subnetworks. Furthermore, we find that the underlying mechanisms for these two bursting synchronization transitions are different: one is due to the change of spike numbers per burst, while the other is caused by the change of the bursting type. Considering that changes in the coupling strengths and neuronal connections are closely interlaced with brain plasticity, the presented results could have important implications for the role of the brain plasticity in some functional behavior that are associated with synchronization.
Spintronic chip cytometer
Authors: Loureiro J. , Andrade P. Z. , Cardoso S. , da Silva C. L. , Cabral J. M. , Freitas P. P.
Published: April 2011

Modern flow cytometers are being developed with enhanced portability for on-site measurements, and by integrating magnetoresistive sensors within microfluidic channels (to detect magnetically labeled cells), external and expensive equipment can be avoided. This work describes the real-time detection of Kg1-a cells magnetically labeled with 50 nm magnetic particles using a magnetoresistive based cell cytometer. When flowing through a microchannel 150 μm wide and 14 μm high, with speeds around 1 cm/s, the average observed signals were bipolar with an amplitude of 10 to 20 μV (0-p) corresponding to cell events. The number of cells counted by the SV cytometer has been compared with that obtained with a hemocytometer, and both methods agree within the respective error bars.
Structural origin of set-reset process in a new bulk Si15Te83Ge2 phase-change memory material
Authors: Gunti Srinivasa Rao , Asokan S.
Published: April 2011

A new phase-change memory material, in bulk, has been prepared by melt-quenching technique, which has a better glass forming ability. This sample is set and resettable relatively easily for several cycles at 2mA SET and RESET input currents, and is likely to be a suitable material for phase-change memory applications. Raman scattering studies have been undertaken during the SET and RESET operations to elucidate the local structural transformations that occur during these operations.
On the influence that the ground electrode diameter has in the propulsion efficiency of an asymmetric capacitor in nitrogen gas
Authors: Martins Alexandre A. , Pinheiro Mario J.
Published: April 2011

In this work, the propulsion force developed in an asymmetric capacitor will be calculated for three different diameters of the ground electrode. The used ion source is a small diameter wire, which generates a positive corona discharge in nitrogen gas directed to the ground electrode. By applying the fluid dynamic and electrostatic theories, all hydrodynamic and electrostatic forces that act on the considered geometries will be computed in an attempt to provide a physical insight on the force mechanism that acts on the asymmetrical capacitors, and also to understand how to increase the efficiency of propulsion.
Broadband cloaking using composite dielectrics
Authors: Hwang Ruey-Bing , Chin Cheng-Yuan
Published: April 2011

In this paper, we present a novel cloaking structure that is able to make a metallic block invisible in a metallic waveguide. Such a cloak is made up of a stack of commonly used dielectric slabs. We carry out the numerical simulation and observe the detour of the vector Poynting power through the cloak. Moreover, the experiment is conducted for measuring the scattering characteristics including the reflection and transmission coefficients. The great improvement in the transmission coefficient in a broad bandwidth after cloaking is demonstrated. Significantly, the theory of mode conversion is developed for explaining the cloaking phenomenon.
Investigation of the photoluminescence properties of thermochemically synthesized CdS nanocrystals
Authors: Molaei M. , Iranizad E. Saievar , Marandi M. , Taghavinia N.
Published: April 2011

In this work we have synthesized CdS nanocrystals with thermochemical method. CdSO4 and Na2S2O3 were used as the precursors and thioglycolic acid (TGA) was used as capping agent molecule. The structure and optical property of the nanocrystals were characterized by means of XRD, TEM, UV-visible optical spectroscopy and photoluminescence (PL). X-ray diffraction (XRD) and TEM analyses demonstrated hexagonal phase CdS nanocrystals with an average size around 2 nm. Synthesized nanocrystals exhibited band gap of about 3.2 eV and showed a broad band emission from 400-750 nm centered at 504 nm with a (0.27, 0.39) CIE coordinate. This emission can be attributed to recombination of an electron in conduction band with a hole trapped in Cd vacancies near to the valance band of CdS. The best attained photoluminescence quantum yield of the nanocrystals was about 12%, this amount is about 20 times higher than that for thioglycerol (TG) capped CdS nanocrystals.
Exact diagonalization of 1D interacting spinless Fermions
Authors: Kohler Heiner
Published: April 2011

We acquire a method of constructing an infinite set of exact eigenfunctions of 1D interacting spinless Fermionic systems. Creation and annihilation operators for the interacting system are found and thereby the many-body Hamiltonian is diagonalized. The formalism is applied to several examples. One example is the theory of Jack polynomials. For the Calogero–Moser–Sutherland Hamiltonian a direct proof is given that the asymptotic Bethe ansatz is correct.
Mesoscale and clusters of synchrony in networks of bursting neurons
Authors: Belykh Igor , Hasler Martin
Published: April 2011

We study the role of network architecture in the formation of synchronous clusters in synaptically coupled networks of bursting neurons. We give a simple combinatorial algorithm that finds the largest synchronous clusters from the network topology. We demonstrate that networks with a certain degree of internal symmetries are likely to have cluster decompositions with relatively large clusters, leading potentially to cluster synchronization at the mesoscale network level. We also address the asymptotic stability of cluster synchronization in excitatory networks of Hindmarsh–Rose bursting neurons and derive explicit thresholds for the coupling strength that guarantees stable cluster synchronization.
Dynamics of electron solvation in I−(CH3OH)n clusters (4 ≤ n ≤ 11)
Authors: Young Ryan M. , Yandell Margaret A. , Neumark Daniel M.
Published: April 2011

The dynamics of electron solvation following excitation of the charge-transfer-to-solvent precursor state in iodide-doped methanol clusters, I−(CH3OH)n=4–11, are studied with time-resolved photoelectron imaging. This excitation produces a I…(CH3OH)n− cluster that is unstable with respect to electron autodetachment and whose autodetachment lifetime increases monotonically from ∼800 fs to 85 ps as n increases from 4 to 11. The vertical detachment energy (VDE) and width of the excited state feature in the photoelectron spectrum show complex time dependence during the lifetime of this state. The VDE decreases over the first 100–400 fs, then rises exponentially to a maximum with a ∼1 ps time constant, and finally decreases by as much as 180 meV with timescales of 3–20 ps. The early dynamics are associated with electron transfer from the iodide to the methanol cluster, while the longer-time changes in VDE are attributed to solvent reordering, possibly in conjunction with ejection of neutral iodine from the cluster. Changes in the observed width of the spectrum largely follow those of the VDEs; the dynamics of both are attributed to the major rearrangement of the solvent cluster during relaxation. The relaxation dynamics are interpreted as a reorientation of at least one methanol molecule and the disruption and formation of the solvent network in order to accommodate the excess charge.
Fast electro-optic switching in liquid crystal blue phase II
Authors: Choi Hyunseok , Higuchi Hiroki , Kikuchi Hirotsugu
Published: April 2011

Electro-optic switching based on the Kerr effect was investigated in detail for liquid crystal blue phase II (BPII) with different chiral pitch. The Kerr constant of BPII was found to be proportional to the cube of the chiral pitch, although the theoretical expectation was the square of the chiral pitch. In addition, there was little hysteresis in the voltage-transmittance curve of BPII. The response of BPII was found to be very fast, at less than 1 ms, in both the regions of local director reorientation and electrostriction by applied electric field.
Chaotic phase synchronization in small-world networks of bursting neurons
Authors: Yu Haitao , Wang Jiang , Deng Bin , Wei Xile , Wong Y. K. , Chan W. L. , Tsang K. M. , Yu Ziqi
Published: April 2011

We investigate the chaotic phase synchronization in a system of coupled bursting neurons in small-world networks. A transition to mutual phase synchronization takes place on the bursting time scale of coupled oscillators, while on the spiking time scale, they behave asynchronously. It is shown that phase synchronization is largely facilitated by a large fraction of shortcuts, but saturates when it exceeds a critical value. We also study the external chaotic phase synchronization of bursting oscillators in the small-world network by a periodic driving signal applied to a single neuron. It is demonstrated that there exists an optimal small-world topology, resulting in the largest peak value of frequency locking interval in the parameter plane, where bursting synchronization is maintained, even with the external driving. The width of this interval increases with the driving amplitude, but decrease rapidly with the network size. We infer that the externally applied driving parameters outside the frequency locking region can effectively suppress pathologically synchronized rhythms of bursting neurons in the brain.