bluuebunny/crossref_metadata_2025 huggingface dataset:
Online Social Media and Political Awareness in Authoritarian Regimes
Authors: Reuter Ora John , Szakonyi David
Published: September 2013

Do online social media undermine authoritarianism? The conditions under which online social networks can increase public awareness of electoral fraud in non-democracies are examined in this article and it is argued that a given online social network will only increase political awareness if it is first politicized by elites. Survey data from the 2011 Russian parliamentary elections show that usage of Twitter and Facebook, which were politicized by opposition elites, significantly increased respondents’ perceptions of electoral fraud, while usage of Russia's domestic social networking platforms, VKontakte and Odnoklassniki, which were not politicized by opposition activists, had no effect on perceptions of fraud. This study elucidates the causes of post-election protest by uncovering a mechanism through which knowledge of electoral fraud spreads.
Metabolic engineering ofLactococcus lactisinfluence of the overproduction of lipase enzyme
Authors: Raftari Mohammad , Ghafourian Sobhan , Bakar Fatimah Abu
Published: September 2013

The dairy industry uses lipase extensively for hydrolysis of milk fat. Lipase is used in the modification of the fatty acid chain length, to enhance the flavours of various chesses. Therefore finding the unlimited source of lipase is a concern of dairy industry. Due to the importance of lipase, this study was an attempt to express the lipase fromBurkholderia cepaciainLactococcus lactis.To achieve this, a gene associated with lipase transport was amplified and subcloned in inducible pNZ8148 vector, and subsequently transformed intoLc. lactisNZ9000. The enzyme assay as well as SDS-PAGE and western blotting were carried out to analysis the recombinant lipase expression. Nucleotide sequencing of the DNA insert from the clone revealed that the lipase activity corresponded to an open reading frame consisting of 1092 bp coding for a 37·5-kDa size protein. Blue colour colonies on nile blue sulphate agar and sharp band on 37·5-kD size on SDS-PAGE and western blotting results confirm the successful expression of lipase byLc. lactis. The protein assay also showed high expression, approximately 152·2 μg/ml.h, of lipase by recombinantLc. lactis.The results indicate thatLc. lactishas high potential to overproduce the recombinant lipase which can be used commercially for industrially purposes.
Technological characterisation, antibiotic susceptibility and antimicrobial activity of wild-typeLeuconostocstrains isolated from north Italian traditional cheeses
Authors: Morandi Stefano , Cremonesi Paola , Silvetti Tiziana , Brasca Milena
Published: September 2013

Genotypic and technological properties, antibiotic susceptibility and antimicrobial activity of 35Leuconostocstrains, isolated from different Italian raw milk cheeses, were investigated. RAPD-PCR was used to study genetic variability and to distinguish closely related strains. The results showed a high degree of heterogeneity among isolates. All the strains had weak acidifying activity and showed low proteolytic and lipolytic activities. Reduction activity, was generally low. All theLeuconostocwere susceptible to ampicillin, mupirocin, erythromycin, quinupristin/dalfopristin and tetracycline. Many strains were classified as resistant to oxacillin, ciprofloxacin and nitrofurantonin, while all isolates were found resistant to vancomycin. PCR-based detection did not identify any of the common genetic determinants for vancomycin (vanA,vanB,vanC1,vanC2,vanC3,vanD,vanE,vanG) or erythromycin (ermB andermC). Tetracycline resistance genes were detected in 25 tetracycline susceptible strains, the most frequent one beingtetM. One strain, belonging toLn. pseudomesenteroidesspecies, was positive for the presence of theintgene of the Tn916/Tn1545trasposon family. This is the first time the conjugative transposon Tn916has been detected inside theLeuconostocspecies. All strains showed antimicrobial activity againstEnterococcus faecalisandEnt. faecium. The presence of genes encoding amino-acid decarboxylases (hdcandtdc) was not detected. Some strains are interesting in view of their use in cheese production as starter and non starter cultures.
Risk of adolescent offspring's completed suicide increases with prior history of their same-sex parents' death by suicide
Authors: Cheng C.-C. J. , Yen W.-J. , Chang W.-T. , Wu K. C.-C. , Ko M.-C. , Li C.-Y.
Published: September 2013

Background

To investigate the risk of completed suicide in offspring during adolescence in relation to prior history of the same-sex parent's death by suicide and other causes.

Method

A total of 500 adolescents who died by suicide at age 15–19 years between 1997 and 2007 were identified from the Taiwan Mortality Registration (TMR). For each case, 30 age- and time-matched controls were selected randomly from all adolescents registered in the Taiwan Birth Registry (TBR). A multivariate conditional logistic regression model was used to assess the risk of adolescent completed suicide in relation to their same-sex parent.

Results

Adolescent suicide risk was positively associated with both paternal [odds ratio (OR) 5.38, 95% confidence interval (CI) 2.17–13.33] and maternal suicide (OR 6.59, 95% CI 1.82–23.91). The corresponding risk estimates associated with paternal and maternal deaths from non-suicidal causes were much lower, at 1.88 and 1.94 respectively. The risk of suicide in male adolescents was significantly associated with prior history of paternal death by suicide (OR 8.23, 95% CI 2.96–22.90) but not of maternal death by suicide (OR 3.50, 95% CI 0.41–30.13). On the other contrary, the risk of suicidal death in female adolescents was significantly associated with prior history of maternal suicide (OR 9.71, 95% CI 1.89–49.94) but not of paternal suicide (OR 2.42, 95% CI 0.30–19.57). However, these differences did not reach statistical significance.

Conclusions

Although limited by sample size, our study indicates that adolescent offspring suicidal death is associated with prior history of their same-sex parent's death by suicide.
Three-year longitudinal population-based volumetric MRI study in first-episode schizophrenia spectrum patients
Authors: Roiz-Santiáñez R. , Ayesa-Arriola R. , Tordesillas-Gutiérrez D. , Ortiz-García de la Foz V. , Pérez-Iglesias R. , Pazos A. , Sánchez E. , Crespo-Facorro B.
Published: September 2013

Background

Schizophrenia is a chronic brain disorder associated with structural brain abnormalities already present at the onset of the illness. Whether these brain abnormalities might progress over time is still under debate.

Method

The aim of this study was to investigate likely progressive brain volume changes in schizophrenia during the first 3 years after initiating antipsychotic treatment. The study included 109 patients with a schizophrenia spectrum disorder and a control group of 76 healthy subjects. Subjects received detailed clinical and cognitive assessment and structural magnetic resonance imaging (MRI) at regular time points during a 3-year follow-up period. The effects of brain changes on cognitive and clinical variables were examined along with the impact of potential confounding factors.

Results

Overall, patients and healthy controls exhibited a similar pattern of brain volume changes. However, patients showed a significant lower progressive decrease in the volume of the caudate nucleus than control subjects (F1,307.2 = 2.12, p = 0.035), with healthy subjects showing a greater reduction than patients during the follow-up period. Clinical and cognitive outcomes were not associated with progressive brain volume changes during the early years of the illness.

Conclusions

Brain volume abnormalities that have been consistently observed at the onset of non-affective psychosis may not inevitably progress, at least over the first years of the illness. Taking together with clinical and cognitive longitudinal data, our findings, showing a lack of brain deterioration in a substantial number of individuals, suggest a less pessimistic and more reassuring perception of the illness.
The Inbetweenness of Sympotic Elegy
Authors: Budelmann Felix , Power Timothy
Published: September 2013

This article revisits the question of how elegy was performed at the symposion, and argues that, rather than being either musical or non-musical, elegy situates itself between speech and song. None of the passages in which elegy mentions song are clearly self-referential: they tend to be generic, set in the future, concerned with other performers and other compositions or altogether too slippery in their language to pin them down. Moreover, there are a number of elegiac pieces that appear designed to allow symposiasts to shift from song to speech or speech to song, thereby introducing a new mode of performance, and so are themselves transitional. These observations about the way elegiac texts position their own performance are complemented by considerations about their actual performance. Evidence both from ancient musicologists and from other tonal languages suggests that inbetween modes of delivery were common in Greek poetry and the metrical shape makes elegy a prime candidate. The final section of the article turns to the difficult term elegos in fifth-century drama. It argues that several of these passages draw on inbetweenness as one association of elegos and thus decreases the gap between elegos and surviving elegy. A coda points out that the elegiacs in Euripides' Andromache are a further example of elegy transitioning between two modes of performance.
The Origins of the Athenian Economic ARCHE
Authors: Kallet Lisa
Published: September 2013

Histories of the Athenian Empire (478–404 BC) have traditionally been offered as political and military narratives. They explain the origins of a naval alliance created in 478/7 BC, the so-called Delian League under Athenian leadership and its development into an ‘empire’ (arche) sometime in mid-century. Moreover, most treat the phenomenon as comprehensible as a self-contained period of enquiry. This article takes issue with both approaches. Through close examination of a wide variety of evidence connected with Athenian activity during the formative years of the ‘Delian League’ (478 to ca. 465), it argues that the Athenians made immediate use of the League navy and funds to appropriate resources, profits and territory for themselves, especially in Thrace, beginning with the capture of Eion on the Strymon, but also that these interests explain other early activities. Finally, it argues that the Athenians' economic behaviour should be understood in the context of Athenian aims and activities in the Archaic period.
Content and Language Integrated Learning: A research agenda
Authors: Dalton-Puffer Christiane , Smit Ute
Published: September 2013

While Content and Language Integrated Learning (CLIL) has received a considerable amount of research interest lately, its increasing popularity as an approach to teaching content subjects in a foreign language requires concerted investigation that reflects and recognises its fundamentally contextualised nature. In this contribution, we sketch various tasks that require localised, often action research, covering a range of areas highly relevant to CLIL realities, but so far underrepresented in the literature. These are, firstly, policy issues, comprising policy statements as well as stakeholders’ perceptions of CLIL and its success; secondly, classroom discourse as the prime site for the investigation of CLIL practices and their implications for the learning process; and, thirdly, classroom pedagogy, with the focus on potential differences between CLIL and non-CLIL settings.
Emergent bilingual students in secondary school: Along the academic language and literacy continuum
Authors: Menken Kate
Published: September 2013

This article offers a critical review of research about emergent bilingual students in secondary school, where the academic demands placed upon them are great, and where instruction typically remains steadfast in its monolingualism. I focus on recent scholarship about the diversity within this student population, and center on ‘students with interrupted formal education’ (SIFE, new arrivals who have no home language literacy skills or are at the beginning stages of literacy learning) and ‘long-term English language learners’ (LTELLs, primarily educated in their receiving country yet still eligible for language support services). Little has been published about these students, making this a significant area of inquiry. Moreover, both groups are characterized by poor performance and together illustrate the characteristics of secondary students at various points along an academic language and literacy continuum. While existing research provides important information to help us improve secondary schooling for emergent bilinguals, it has also perpetuated deficit views of these students by focusing solely on their perceived academic shortcomings. Grounded in a new body of research in applied linguistics that examines the students’ complex, creative, and dynamic language and literacy practices, I apply a translanguaging lens to critique the positioning of such students as deficient, with implications for research and practice.
Research at the Centre for Educational Research on Languages and Literacies (CERLL) at the Ontario Institute for Studies in Education of the University of Toronto (OISE/UT)
Authors: Kohls Robert , Wilson Jennifer Shade
Published: September 2013

After more than 40 years as the Modern Language Centre, members of the Centre decided to rename ourselves as the Centre for Educational Research on Languages and Literacies (CERLL), to better reflect our current activities and interests. We officially launched the new name for the Centre at a reception on 22 October 2010, and produced a compilation of recent publications by members of the Centre to mark the event. Our interests in research and graduate studies remain fundamentally as they have been for decades, focused on theories and practices in teaching, learning, curriculum, assessment, and policies related to English and French as second or international languages as well as other international, minority, heritage, or indigenous languages. The name change does signal a broadening of perspectives to include research on various forms and types of literacies, though we do not claim to be ‘post-modern’ in doing so.
Group membership and identity issues in second language learning
Authors: Trofimovich Pavel , Turuševa Larisa , Gatbonton Elizabeth
Published: September 2013

Language learning is inextricably linked to a social context, and this implies that context-related social variables, such as ethnicity or attitudes, can influence how language learning unfolds. Among the many group-engendered social factors, ethnic identity appears to have interesting consequences for language teaching and learning (Pavlenko & Blackledge 2004). Indeed, issues of personal and group identity often become important when individuals or groups come in contact with one another to learn a language. Briefly, ethnic identity refers to a person's subjective experience of being a part of an ethnic group (Ashmore, Deaux & McLaughlin-Volpe 2004). For second language (L2) learners, the two relevant groups are usually their primary (home) ethnic group and the L2 community. We report here on the research that we have been conducting at Concordia University in Montreal, as part of the Centre for the Study of Learning and Performance, with the goal of investigating the role of ethnic group identity in L2 learning.
Direct observation of particles with energy >10 MeV/u from laser-induced processes with energy gain in ultra-dense deuterium
Authors: Holmlid Leif
Published: September 2013

Nuclear fusion in ultra-dense deuterium D(-1) was reported previously to be induced by 0.2 J pulses with 5 ns pulse length, ejecting particles with energies in the MeV range. The ns-resolved signal from D(-1) to two in-line collectors at up to 1 m distance can be observed directly on an oscilloscope, showing particles with energies in the range 1–20 MeV u−1. They are probably mainly protons and deuterons in the form of neutral ultra-dense hydrogen H(-1) fragments. Electrons and photons give only small contributions to the fast signal. The observed signal at several mA peak current corresponds to 1 × 1013 particles released per laser shot and to an energy release >4 J assuming isotropic formation and average particle energy of 3 MeV. This corresponds to an energy gain of 30 in the process. A movable slit close to the laser target gives lateral resolution of the signal generation, showing almost only fast particles from the point of laser impact and penetrating photons from the plasma outside the laser impact point. The observation of multi-MeV particles indicates nuclear fusion, either as a source or as a result.
Assessing language dominance in Mandarin–English bilinguals: Convergence and divergence between subjective and objective measures
Authors: SHENG LI , LU YING , GOLLAN TAMAR H.
Published: September 2013

This study examines the convergence and divergence between subjective and objective measures of language proficiency for assessing language dominance in Mandarin–English bilinguals. Sixty-two young adults (Experiment 1) and 27 children (Experiment 2) provided self-ratings of proficiency level (or were rated by their parents), were interviewed for spoken proficiency, and named pictures in the Multilingual Naming Test (MINT) and (in Experiment 1 only) the Boston Naming Test. In Experiment 1, the four measures converged in the number of people classified into different dominance groups but both naming tests indicated greater English dominance than self-report and interview measures. In Experiment 2, parent report and interview measures converged in dominance classifications but the MINT indicated higher degrees of English dominance. To a large extent bilinguals were able to classify themselves (or their children) into dominance groups but some mismatches between measures in dominance classification were observed for all age and dominance groups. These results, together with previous findings with Spanish–English bilingual adults (Gollan et al., 2012), suggest that bilinguals may shift to English dominance in confrontation naming before they do so in conversational fluency, and that dominance shifts persist throughout the lifespan but may be relatively more pronounced in children. These findings caution against the use of self-reports as the sole means of classifying bilinguals into dominance groups and support a multi-measure approach including direct assessment of the relevant linguistic domain.
Beauty or brains? The braincase ofPachyrhinosaurus perotorumand its utility for species-level distinction in the centrosaurine ceratopsidPachyrhinosaurus
Authors: Tykoski Ronald S. , Fiorillo Anthony R.
Published: September 2013

The centrosaurine ceratopsid taxonPachyrhinosaurusis the most speciose of centrosaurines, being represented by at least three species (P. canadensis,P. lakustai, and the recently describedP. perotorum) from the late Campanian and early Maastrichtian of North America. The species are readily distinguished from one another by details of easily visible cranio-facial and frill ornamentation, features commonly used to differentiate ceratopsid taxa. Braincase material is also known for all three taxa. We describe the braincase ofP. perotorumbased on specimens from the Kikak–Tegoseak Quarry of the North Slope of Alaska. We then compare it to braincase and endocranial descriptions of the otherPachyrhinosaurustaxa to test whether there may be useful species-level differences present in these robust parts of the ceratopsid skull. Braincase morphology, including cranial nerve paths through the braincase walls inP. lakustaiandP. perotorum, were found to be very similar. Two potential diagnostic differences between taxa were found, although tests based on larger sample sizes will be necessary to verify them. This reinforces the importance of highly visual cranio-facial and frill ornamentation as the best tool for species recognition and phylogenetic reconstruction in ceratopsid dinosaurs.
What Do the Bereaved by Suicide Communicate in Online Support Groups?
Authors: Schotanus-Dijkstra Marijke , Havinga Petra , van Ballegooijen Wouter , Delfosse Lynn , Mokkenstorm Jan , Boon Brigitte
Published: September 2013

Background: Every year, more than six million people lose a loved one through suicide. These bereaved by suicide are at relatively high risk for mental illnesses including suicide. The social stigma attached to suicide often makes it difficult to talk about grief. Participating in online forums may be beneficial for the bereaved by suicide, but it is unknown what they communicate in these forums. Aims: What do the bereaved by suicide communicate in online forums? We examined which self-help mechanisms, grief reactions, and experiences with health-care services they shared online. Method: We conducted a content analysis of 1,250 messages from 165 members of two Dutch language forums for the bereaved by suicide. Results: We found that sharing personal experiences featured most prominently in the messages, often with emotional expressions of grief. Other frequently used self-help mechanisms were expressions of support or empathy, providing advice, and universality (recognition), while experiences with health-care services featured only occasionally. Compared with previous studies about online forums for somatic illnesses, the bereaved by suicide communicated more personal experiences and engaged much less in chitchat. Conclusion: Online forums appear to have relevant additional value as a platform for talking about grief and finding support.
Exposure to Political Violence and Political Extremism
Authors: Canetti Daphna , Hall Brian J. , Rapaport Carmit , Wayne Carly
Published: September 2013

Exposure to political violence can lead to various political and psychological outcomes. Using the protracted Israeli-Palestinian conflict as a natural laboratory, we explore the way in which exposure to conflict violence leads to changes in citizens’ political attitudes and behavior, offering a model for a stress-based process of political extremism. This model encapsulates three basic components in a causal chain leading to political extremism: exposure to political violence, psychological distress, and enhanced perceptions of threat. We find that prolonged exposure to political violence increases psychological distress, which in turn evokes stronger perceptions of threat that foment political attitudes eschewing compromise and favoring militarism. This causal chain fuels a destructive cycle of violence that is hard to break. Understanding these psychological and political consequences of exposure to political violence can help to shed light on the barriers that too often stymie peacemaking efforts and contribute to the deterioration of intractable conflicts around the globe. Thus, this review offers insights applicable to conflict zones around the world and suggests policy implications for therapeutic intervention and potential pathways to conflict resolution.
Foxo‐mediated Bim transcription is dispensable for the apoptosis of hematopoietic cells that is mediated by this BH3‐only protein
Authors: Herold Marco J , Rohrbeck Leona , Lang Mathias J , Grumont Raelene , Gerondakis Steve , Tai Lin , Bouillet Philippe , Kaufmann Thomas , Strasser Andreas
Published: September 2013

The BH3‐only protein Bim is a critical initiator of apoptosis in hematopoietic cells. Bim is upregulated in response to growth factor withdrawal and in vitro studies have implicated the transcription factor Foxo3a as a critical inducer. To test the importance of this regulation in vivo, we generated mice with mutated Foxo‐binding sites within the Bim promoters (BimΔFoxo/ΔFoxo). Contrary to Bim‐deficient mice, BimΔFoxo/ΔFoxo mice had a normal hematopoietic system. Moreover, cytokine‐dependent haematopoietic cells from BimΔFoxo/ΔFoxo and wt mice died at similar rates. These results indicate that regulation of Bim by Foxo transcription factors is not critical for the killing of hematopoietic cells.
Microbial expression profiles in the rhizosphere of willows depend on soil contamination
Authors: Yergeau Etienne , Sanschagrin Sylvie , Maynard Christine , St-Arnaud Marc , Greer Charles W
Published: September 2013

The goal of phytoremediation is to use plants to immobilize, extract or degrade organic and inorganic pollutants. In the case of organic contaminants, plants essentially act indirectly through the stimulation of rhizosphere microorganisms. A detailed understanding of the effect plants have on the activities of rhizosphere microorganisms could help optimize phytoremediation systems and enhance their use. In this study, willows were planted in contaminated and non-contaminated soils in a greenhouse, and the active microbial communities and the expression of functional genes in the rhizosphere and bulk soil were compared. Ion Torrent sequencing of 16S rRNA and Illumina sequencing of mRNA were performed. Genes related to carbon and amino-acid uptake and utilization were upregulated in the willow rhizosphere, providing indirect evidence of the compositional content of the root exudates. Related to this increased nutrient input, several microbial taxa showed a significant increase in activity in the rhizosphere. The extent of the rhizosphere stimulation varied markedly with soil contamination levels. The combined selective pressure of contaminants and rhizosphere resulted in higher expression of genes related to competition (antibiotic resistance and biofilm formation) in the contaminated rhizosphere. Genes related to hydrocarbon degradation were generally more expressed in contaminated soils, but the exact complement of genes induced was different for bulk and rhizosphere soils. Together, these results provide an unprecedented view of microbial gene expression in the plant rhizosphere during phytoremediation.
Efficient Gate-tunable light-emitting device made of defective boron nitride nanotubes: from ultraviolet to the visible
Authors: Attaccalite Claudio , Wirtz Ludger , Marini Andrea , Rubio Angel
Published: September 2013

Boron nitride is a promising material for nanotechnology applications due to its two-dimensional graphene-like, insulating and highly-resistant structure. Recently it has received a lot of attention as a substrate to grow and isolate graphene as well as for its intrinsic UV lasing response. Similar to carbon, one-dimensional boron nitride nanotubes (BNNTs) have been theoretically predicted and later synthesised. Here we use first principles simulations to unambiguously demonstrate that i) BN nanotubes inherit the highly efficient UV luminescence of hexagonal BN; ii) the application of an external perpendicular field closes the electronic gap keeping the UV lasing with lower yield; iii) defects in BNNTS are responsible for tunable light emission from the UV to the visible controlled by a transverse electric field (TEF). Our present findings pave the road towards optoelectronic applications of BN-nanotube-based devices that are simple to implement because they do not require any special doping or complex growth.
Realising Haldane's vision for a Chern insulator in buckled lattices
Authors: Wright Anthony R.
Published: September 2013

The Chern insulator displays a quantum Hall effect with no net magnetic field. Proposed by Haldane over 20 years ago, it laid the foundation for the fields of topological order, unconventional quantum Hall effects and topological insulators. Despite enormous impact over two decades, Haldane's original vision of a staggered magnetic field within a crystal lattice has been prohibitively difficult to realise. In fact, in the original paper Haldane stresses his idea is probably merely a toy model. I show that buckled lattices with only simple hopping terms, within in-plane magnetic fields, can realise these models, requiring no exotic interactions or experimental parameters. As a concrete example of this very broad and remarkably simple principle, I consider silicene, a honeycomb lattice with out-of-plane sublattice anisotropy, in an in-plane magnetic field and show that it is a Chern insulator, even at negligibly small magnetic fields, which is analogous to Haldane's original model.
Maternal anxiety and infants' hippocampal development: timing matters
Authors: Qiu A , Rifkin-Graboi A , Chen H , Chong Y-S , Kwek K , Gluckman P D , Fortier M V , Meaney M J
Published: September 2013

Exposure to maternal anxiety predicts offspring brain development. However, because children’s brains are commonly assessed years after birth, the timing of such maternal influences in humans is unclear. This study aimed to examine the consequences of antenatal and postnatal exposure to maternal anxiety upon early infant development of the hippocampus, a key structure for stress regulation. A total of 175 neonates underwent magnetic resonance imaging (MRI) at birth and among them 35 had repeated scans at 6 months of age. Maternal anxiety was assessed using the State-Trait Anxiety Inventory (STAI) at week 26 of pregnancy and 3 months after delivery. Regression analyses showed that antenatal maternal anxiety did not influence bilateral hippocampal volume at birth. However, children of mothers reporting increased anxiety during pregnancy showed slower growth of both the left and right hippocampus over the first 6 months of life. This effect of antenatal maternal anxiety upon right hippocampal growth became statistically stronger when controlling for postnatal maternal anxiety. Furthermore, a strong positive association between postnatal maternal anxiety and right hippocampal growth was detected, whereas a strong negative association between postnatal maternal anxiety and the left hippocampal volume at 6 months of life was found. Hence, the postnatal growth of bilateral hippocampi shows distinct responses to postnatal maternal anxiety. The size of the left hippocampus during early development is likely to reflect the influence of the exposure to perinatal maternal anxiety, whereas right hippocampal growth is constrained by antenatal maternal anxiety, but enhanced in response to increased postnatal maternal anxiety.
A polycyclic borazine radical cation: [1,2-B2{1,2-(MeN)2C6H4}2]˙+
Authors: Xie Xiaochen , Adams Christopher J. , Al-Ibadi Muhsen A. M. , McGrady John E. , Norman Nicholas C. , Russell Christopher A.
Published: September 2013

The radical cation, [1,2-B2{1,2-(MeN)2C6H4}2]˙+, has been prepared and characterised by X-ray crystallography, ESR and DFT calculations.
Exact BER analysis of FRFT‐OFDM system over frequency selective Rayleigh fading channel with CFO
Authors: Kumari S. , Rai S. Kr. , Kumar A. , Joshi H. D. , Singh A. Kr. , Saxena R.
Published: September 2013

The bit error rate expression of the binary phase‐shift keying modulation scheme has been derived in a frequency selective fading channel for the fractional Fourier transform (FRFT) based orthogonal frequency‐division multiplexing (OFDM) system in the presence of carrier frequency offset (CFO). The performance of the FRFT based OFDM system has been found to be better than FFT‐based OFDM at different values of FRFT angle parameter ‘α’.
Design of dual‐polarised compact base station antenna with high isolation using spiral resonator
Authors: Lee Jung N. , Jung Jae H. , Lee Kwang C.
Published: September 2013

A dual‐polarised compact base station antenna with high isolation is presented. High isolation is achieved by using a shorted spiral resonator placed below the metallic radiating patch. From the experimental results, the measured impedance bandwidth of the proposed antenna is 1.7–1.9 GHz for micro‐cell systems and the isolation is more than 30 dB. The proposed antenna exhibits good radiation patterns and peak gain is 8 dBi.
Imaging algorithm for circular trace scanning synthetic aperture radar using modified hyperbolic range equation
Authors: Liao Yi , Xing Mengdao , Bao Zheng
Published: September 2013

For a circular trace scanning synthetic aperture radar (CTSSAR) system, the conventional quadratic range approximation method becomes inefficient when the squint angle exists and the integrated aperture is long. To improve the accuracy in the approximation of the range history for CTSSAR, a modified hyperbolic range equation is introduced to derive the corresponding two‐dimensional spectrum and further develop the imaging algorithm for CTSSAR. Promising results prove the effectiveness of the proposed method.
Compact and switchable dual‐band bandpass filter with high selectivity and wide stopband
Authors: Weng S.‐C. , Hsu K.‐W. , Tu W.‐H.
Published: September 2013

A compact and independently switchable dual‐band bandpass filter is presented. To achieve high selectivity response, transmission zeros beside the two passbands are generated due to crossed coupling. On the other hand, the use of quarter‐wavelength stepped‐impedance resonators can not only miniaturise circuit size but also widen the stopband by arranging the resonant frequencies in a stagger with the same fundamental frequency. The pin diodes are loaded at the end of the resonators as the switching devices to independently control each passband.
Design of long‐range, powerless RFID sensor at 10 GHz
Authors: Donelli M.
Published: September 2013

The design of a radio frequency identifier (RFID) tag sensor based on the modulated scattering technique (MST) is presented. The tag works in the X band at 10 GHz and achieves an operative range of about 10 m with a limited amount of power. The power supply required by the transponder is obtained from the interogating electromagnetic field with a customised rectifying Chockcroft‐Walton multiplier circuit. The communication between the reader and the tag is obtained using the standard EM4102 RFID protocol, the information is carried on by modulating the load of the tag antenna with a suitable switch circuit. The antenna tag, the rectifying circuit and the switch have been optimised to reach the maximum operative range. A tag prototype has been designed, fabricated and experimentally assessed. The obtained experimental results are quite good.
Modified variable step‐size affine projection sign algorithm
Authors: Zhang S. , Zhang J.
Published: September 2013

A modified variable step‐size affine projection sign algorithm (MVSS‐APSA) is proposed. Considering the effect of the noise on the steady‐state error, the first moment estimation of the noise is utilised to modify the variable step‐size update. The test on system identifications under an impulsive noise environment shows that the proposed MVSS‐APSA has lower steady‐state misalignment than the VSS‐APSA.
Design of balanced dual‐band bandpass filter based on substrate integrated waveguide
Authors: Xu Xin , Wang Jianpeng , Zhang Gang , Chen Jianxin
Published: September 2013

For the first time, a balanced dual‐band bandpass filter using a substrate integrated waveguide structure is reported. The co‐shared TE102‐mode cavities arranged on the symmetrical plane can greatly reduce the common‐mode signal while selectively transmitting the differential‐mode (DM) signal. In addition, the desired DM response can be easily analysed and obtained by the equivalent 2‐port circuit model. To validate the design concept, one X‐band prototype has been fabricated and tested. The measured results match well with the theoretical counterparts.
Non‐radiative composite right/left‐handed transmission line based on ridge substrate integrated waveguide
Authors: Yang Qingshan , Zhang Yunhua
Published: September 2013

A composite right/left‐handed (CRLH) transmission line (TL) based on a ridge substrate integrated waveguide (RSIW) is proposed and investigated. Its guided wave properties of backward‐wave supporting are studied. This CRLH TL is realised by etching an interdigital capacitor on the ridge surface of the original RSIW. The CRLH TL is fabricated on a multilayer printed circuit board. Both the simulated and measured results are presented. Compared with other non‐radiative CRLH waveguides proposed before, this RSIW‐based CRLH TL has the advantages of miniaturised size, low profile, low cost etc. Besides, unlike other proposed planar CRLH TLs, this closed planar CRLH structure can keep the energy propagating inside so as to avoid energy leakage. Flexible designs can be developed based on this CRLH RSIW in guided‐wave and radiated‐wave applications.
Reduced liquid water content for cloud attenuation prediction: the impact of temperature
Authors: Luini L. , Riva C. , Capsoni C.
Published: September 2013

The prediction of cloud attenuation relying on the concept of reducing liquid water content to a fixed temperature (wR) is investigated. Based on an extensive dataset of radiosonde observations collected in Europe, the focus is on the quantification of the prediction error due to the approximation introduced with wR. The obtained cloud attenuation results indicate that the approximation error δ is markedly sensitive to the reduction temperature TR and that, specifically, TR = − 5°C turns out to minimise δ in European sites, whatever the frequency of interest in the 20–100 GHz range.
Wideband and compact quasi‐Yagi antenna with bowtie‐shaped drivers
Authors: Wang Hao , Chen Yan , Liu Fangshu , Shi Xiaowei
Published: September 2013

A wideband and compact end‐fire antenna with bowtie‐shape drivers is proposed. Based on a wideband microstrip‐to‐coplanar stripline transition and bowtie‐shaped drivers, a broadband impedance bandwidth of more than 75% (4.70–10.44 GHz) for return loss less than − 15 dB and a gain of 5.0–9.1 dBi are obtained. What is more, the front‐to‐back ratio over the frequency of interest is less than − 10 dB. The overall dimensions of the proposed antenna are only 30 × 24.24 mm2. A prototype is fabricated and measured. The simulated and measured results of the proposed antenna indicate that it is suitable for phased array and microwave imaging systems.
Normalised least‐mean‐square algorithm for adaptive filtering of impulsive measurement noises and noisy inputs
Authors: Jung Sang Mok , Park PooGyeon
Published: September 2013

A bias‐compensated error‐modified normalised least‐mean‐square algorithm is proposed. The proposed algorithm employs nonlinearity to improve robustness against impulsive measurement noise, and introduces an unbiasedness criterion to eliminate the bias due to noisy inputs in an impulsive measurement noise environment. To eliminate the bias properly, a new estimation method for the input noise variance is also derived. Simulations in a system identification context show that the proposed algorithm outperforms the other algorithms because of the improved adaptability to impulsive measurement noise and input noise in the system.
650 GHz SIS mixer fabricated on silicon‐on‐insulator substrate
Authors: Tan B.‐K. , Yassin G. , Grimes P. , Jacobs K.
Published: September 2013

The successful operation of a 650 GHz unilateral finline superconductor–insulator–superconductor mixer with a wide IF bandwidth is reported. The mixer was fabricated using silicon‐on‐insulator (SOI) technology, with planar circuit on‐chip integration. The mixer was tested over the frequency range of 630–702 GHz, and the best recorded DSB noise temperature was 226 K. The measured RF and IF behaviour of the mixer agreed very well with the simulation predictions. This demonstrates that superconducting finline mixers fabricated on an SOI substrate can achieve state‐of‐the‐art performance, and yet are much more compact and highly reproducible, and hence suitable for large‐format arrays in astronomy instruments, at THz frequencies.
Compact and low‐loss silica‐based dual polarisation optical hybrid with PBS based on large geometrical birefringence
Authors: Hashizume Y. , Itoh M. , Hashimoto T. , Itoh M.
Published: September 2013

A low‐loss (8.4–9.0 dB) and compact (3 × 7 mm2) silica‐based dual polarisation optical hybrid has been successfully demonstrated by using a short polarisation beam splitter (PBS) (2.8 mm) based on geometrical birefringence.
Tm3+–Tb3+‐doped tunable fibre ring laser for 1700 nm wavelength region
Authors: Yamada M. , Senda K. , Tanaka T. , Maeda Y. , Aozasa S. , Ono H. , Ota K. , Koyama O. , Ono J.
Published: September 2013

The first tunable fibre ring laser in the 1700 nm wavelength region has been developed. To achieve this fibre laser, a Tm3+–Tb3+‐doped fibre is used as the active fibre, along with a tunable bandpass filter. A fibre ring laser that consisted of a 1.2/1.7 μm band wavelength division multiplexing coupler, a tunable bandpass filter, an active fibre and one 1.21 μm pump laser diode has been realised. A wide tuning wavelength band of 130.4 nm (from 1635.6 to 1766.0 nm) was achieved with a launched pump power of over ∼ 30 mW. The lasing threshold pump power at 1716 nm was ∼ 9 mW.
Preparation of Al–SiC–Al2O3 metal matrix composite powder by mechanochemical reaction between Al, SiO2 and C
Authors: Karbasi Maryam , Razavi Mehdi , Taheri Mina , Vashaee Daryoosh , Tayebi Lobat
Published: September 2013

In this Letter, Al–SiC–Al2O3 metal matrix nanocomposite powder was successfully synthesised employing a mechanical alloying technique, through a mechanochemical reaction among aluminium (Al), silicon dioxide (SiO2) and carbon (C). For commercial purposes, the materials (Al, SiO2 and C powders) and also the method of synthesis (mechanical alloying) is considered to be cost‐effective for production of Al–SiC–Al2O3 nanocomposite. The structural evaluation of powder particles after different milling times was conducted by X‐ray diffractometry, and scanning electron microscopy. The results showed that during ball milling Al, SiO2 and C reacted through a mechanochemical reaction producing Al–SiC–Al2O3 metal matrix nanocomposite powder after 50 h of ball milling and annealing at a temperature of 650°C for 1 h. The crystallite sizes of phases remained in nanometric scale.
Fisher information metric for the Langevin equation and least informative models of continuous stochastic dynamics
Authors: Haas Kevin R. , Yang Haw , Chu Jhih-Wei
Published: September 2013

The evaluation of the Fisher information matrix for the probability density of trajectories generated by the over-damped Langevin dynamics at equilibrium is presented. The framework we developed is general and applicable to any arbitrary potential of mean force where the parameter set is now the full space dependent function. Leveraging an innovative Hermitian form of the corresponding Fokker-Planck equation allows for an eigenbasis decomposition of the time propagation probability density. This formulation motivates the use of the square root of the equilibrium probability density as the basis for evaluating the Fisher information of trajectories with the essential advantage that the Fisher information matrix in the specified parameter space is constant. This outcome greatly eases the calculation of information content in the parameter space via a line integral. In the continuum limit, a simple analytical form can be derived to explicitly reveal the physical origin of the information content in equilibrium trajectories. This methodology also allows deduction of least informative dynamics models from known or available observables that are either dynamical or static in nature. The minimum information optimization of dynamics is performed for a set of different constraints to illustrate the generality of the proposed methodology.
Unsteady peristaltic transport in curved channels
Authors: Ramanamurthy J. V. , Prasad K. M. , Narla V. K.
Published: September 2013

The paper presents a generalized mathematical model describing the unsteady peristaltic flow of a viscous fluid in a two-dimensional curved channel. The flow is investigated in a laboratory frame of reference and the unsteady flow nature is studied by the condition that prescribing volumetric flow rate is equivalent to prescribing normal velocity of the fluid particles at the wall. The momentum and energy equations have been linearized by employing lubrication theory and the analysis is restricted to negligible flow Reynolds number. The expressions for stream function, pressure distribution, shear stress, temperature, and coefficient of heat transfer have been derived. The obtained expressions are utilized to discuss the influences of various emerging parameters on flow phenomenon.
Spectroscopic evidence of the presence of an activation barrier in the otherwise barrierless excited state potential energy surface of auramine-O: A femtosecond fluorescence up-conversion study
Authors: Rather Shahnawaz R. , Sen Pratik
Published: September 2013

A widely acclaimed model for the excited state relaxation dynamics of auramine-O involves orientational relaxation of dimethylanilino moieties along the barrierless excited state potential energy surface (PES). Such a model would necessitate similar excited state dynamics in media offering similar viscous drag. However, we have noticed an interesting experimental observation showing auramine-O to have ∼8 times larger fluorescence quantum yield in chloroform than in methanol, though both the solvents have the same viscosity. The femtosecond fluorescence transients of auramine-O in chloroform surprisingly depict a rise in fluorescence transients, which has not been observed before. This, along with the simultaneous observation of unexpectedly large fluorescence lifetime and multi-exponential transients (in chloroform) questions the thoroughly accepted barrierless model of auramine-O relaxation dynamics, as the barrierless model would demand a short lifetime and single-exponential decay. Temperature dependent quantum yield measurements along with solvent dependent excited state multi-coordinate time-dependent density functional theory calculations further unveil the exact nature of PES. All these results concomitantly conclude that, at-least in chloroform, upon photo-excitation auramine-O must pass over an activation barrier before damping the excited state population into ground state via a sink function through adiabatic coupling of the electronic states.
A lift formula applied to low-Reynolds-number unsteady flows
Authors: Wang Shizhao , Zhang Xing , He Guowei , Liu Tianshu
Published: September 2013

A lift formula for a wing in a rectangular control volume is given in a very simple and physically lucid form, providing a rational foundation for calculation of the lift of a flapping wing in highly unsteady and separated flows at low Reynolds numbers. Direct numerical simulations on the stationary and flapping two-dimensional flat plate and rectangular flat-plate wing are conducted to assess the accuracy of the lift formula along with the classical Kutta-Joukowski theorem. In particular, the Lamb vector integral for the vortex force and the acceleration term of fluid for the unsteady inertial effect are evaluated as the main contributions to the unsteady lift generation of a flapping wing.
Turbulent regimes in the tokamak scrape-off layer
Authors: Mosetto Annamaria , Halpern Federico D. , Jolliet Sébastien , Loizu Joaquim , Ricci Paolo
Published: September 2013

The non-linear turbulent regimes in the tokamak scrape-off layer (SOL) are identified according to the linear instability responsible for the perpendicular transport. Four regions of the SOL operational parameters are determined where turbulence is driven by the inertial or resistive branches of the ballooning mode or of drift waves. The analysis, based on the linear electrostatic drift-reduced Braginskii equations, evaluates the pressure scale length self-consistently from the balance between plasma losses at the vessel and perpendicular turbulent transport. The latter is estimated by assuming that turbulence saturation occurs due to a local flattening of the plasma gradients and associated removal of the linear instability drive; it is also shown that transport is led by the mode that maximizes the ratio of the linear growth to the poloidal wavenumber. The methodology used to identify the turbulent regimes is confirmed by the results of non-linear simulations of SOL turbulence. The identification of the turbulent regimes, the predicted pressure scale length, and the poloidal wavenumber of the leading mode are in reasonable agreement with non-linear simulation results.