bluuebunny/crossref_metadata_2025 huggingface dataset:
The push, pull and mooring effects in virtual migration for social networking sites
Authors: Chang I‐Cheng , Liu Chuang‐Chun , Chen Kuanchin
Published: November 2013

Social networking sites (SNSs) have become increasingly common in recent years, and their use has become integrated into the daily lives of millions of people across the world. Attracting new users and retaining existing ones are critical to the success of SNS providers. This study applies the push‐pull‐mooring model of the migration theory to improve our understanding of factors that influence the switching behavior of SNS users. Following the migration theory, this study empirically examines the three categories of antecedents for SNS switching intention: push (i.e., dissatisfaction and regret), pull (i.e., alternative attractiveness), and mooring (i.e., switching costs) factors. The results show that the three categories of factors had varying degrees of effects on switching intention. Additionally, the strong moderation effects of both pull and mooring factors help answer the question why switching does not necessarily occur when push factors are in effect. Managerial implications are provided.
Representing language, culture, and language users in textbooks: A critical approach to swahili multiculturalism
Authors: Thompson Katrina Daly
Published: November 2013

Using a framework of critical multiculturalism and contrasting it to liberal and conservative approaches to multiculturalism (Kubota, 2004), this article offers a critical analysis of the representations of Swahili users and their cultures in five widely used introductory Swahili as a foreign language textbooks. Findings indicate that while one book takes a conservative approach to multiculturalism, the liberal approach dominates, with reference made to both coastal Swahili first language users and a variety of second language users. However, because all of the textbooks discuss a singular abstract culture without connecting it to any of the categories of Swahili users they identify, the result of both liberal and conservative approaches is a failure to teach culture. The article concludes with suggestions for using critical multiculturalism to help learners understand the diverse linguistic and cultural practices and perspectives of language users rather than abstract notions of a (standard) language or a unified culture.
Ecological and evolutionary responses in complex communities: implications for invasions and eco‐evolutionary feedbacks
Authors: Strauss Sharon Y.
Published: November 2013

It is easier to predict the ecological and evolutionary outcomes of interactions in less diverse communities. As species are added to communities, their direct and indirect interactions multiply, their niches may shift, and there may be increased ecological redundancy. Accompanying this complexity in ecological interactions, is also complexity in selection and subsequent evolution, which may feed back to affect the ecology of the system, as species with different traits may play different ecological roles. Drawing from my own work and that of many others, I first discuss what we currently understand about ecology and evolution in light of simple and diverse communities, and suggest the importance of escape from community complexity per se in the success of invaders. Then, I examine how community complexity may influence the nature and magnitude of eco‐evolutionary feedbacks, classifying eco‐evolutionary dynamics into three general types: those generating alternative stable states, cyclic dynamics, and those maintaining ecological stasis and stability. The latter may be important and yet very hard to detect. I suggest future directions, as well as discuss methodological approaches and their potential pitfalls, in assessing the importance and longevity of eco‐evolutionary feedbacks in complex communities.

Synthesis

The ecology, evolution and eco‐evolutionary dynamics of simple and diverse communities are reviewed. In more diverse communities, direct and indirect interactions multiply, species’ niches often shift, ecological redundancy can increase, and selection may be less directional. Community complexity may influence the magnitude and nature of eco‐evolutionary dynamics, which are classified into three types: those generating alternative stable states, cyclic dynamics, and those maintaining ecological stasis and stability. Strengths and pitfalls of approaches to investigating eco‐evolutionary feedbacks in complex field communities are discussed.
European Integration and the Disembedding of Labour Market Regulation: Transnational Labour Relations at the European Central Bank Construction Site
Authors: Wagner Ines , Lillie Nathan
Published: November 2013

European integration through mutual recognition has facilitated the growth of a pan‐European labour supply system in which transnational subcontractors ‘post’ workers from low‐wage areas to higher wage areas. This allows employers to create spaces of exception in which the national industrial relations system of the country where work occurs does not fully apply. Drawing on interviews with managers, workers, unionists and works councillors at the European Central Bank construction site in Frankfurt, Germany, this article shows how transnational subcontracting allows employers to access, and create competition between, sovereign regulatory regimes. It concludes that high‐cost, high‐collective good national systems such as the German one, which depend on territorial boundedness for their integrity, are likely to be destabilized by this aspect of European integration.
Genetic and environmental influences on adolescent attachment
Authors: Fearon Pasco , Shmueli‐Goetz Yael , Viding Essi , Fonagy Peter , Plomin Robert
Published: November 2013

Background

Twin studies consistently point to limited genetic influence on attachment security in the infancy period, but no study has examined whether this remains the case in later development. This study presents the findings from a twin study examining the relative importance of genetic and environmental influences on attachment in adolescence.

Methods

The sample included 551 twin pairs aged 15 years recruited from the larger Twins Early Development Study (TEDS). Attachment was assessed using a semistructured interview, the Child Attachment Interview.

Results

We found robust associations betweenMZtwins' scores for Coherence and their overall security of attachment (r = .42,p < .001; kappa = .26,p < .001), but substantially lower associations forDZtwins (r = .20,p = .001; kappa = .09,p = .20), suggesting genetic influence on adolescent attachment (and substantial nonshared environment). Model‐fitting analyses confirmed this impression, indicating approximately 40% heritability of attachment and negligible influence of the shared environment.

Conclusions

The results suggest that genes may play an important role in adolescent attachment and point to the potentially distinct aetiological mechanisms involved in individual differences in attachment beyond early childhood.
Managerial Incentives and Stock Price Manipulation
Authors: PENG LIN , RÖELL AILSA
Published: November 2013

We present a rational expectations model of optimal executive compensation in a setting where managers are in a position to manipulate short‐term stock prices and the manipulation propensity is uncertain. We analyze the tradeoffs involved in conditioning pay on long‐ versus short‐term performance and show how manipulation, and investors' uncertainty about it, affects the equilibrium pay contract and the informativeness of prices. Firm and manager characteristics determine the optimal compensation scheme: the strength of incentives, the pay horizon, and the use of options. We consider how corporate governance and disclosure regulations can help create an environment that enables better contracting.
Transjugular intrahepatic portosystemic shunt for Budd–Chiari syndrome: techniques, indications and results on 51 Chinese patients from a single centre
Authors: Qi Xingshun , Guo Wengang , He Chuangye , Zhang Wei , Wu Feifei , Yin Zhanxin , Bai Ming , Niu Jing , Yang Zhiping , Fan Daiming , Han Guohong
Published: November 2013

Background & Aims

In Western countries, transjugular intrahepatic portosytemic shunt (TIPS) is widely applied for the treatment of Budd–Chiari syndrome (BCS). However, the outcome of Chinese BCS patients treated with TIPS is extremely limited. Furthermore, the timing of conversion from percutaneous recanalization to TIPS remains uncertain.

Methods

All consecutive BCS patients treated with TIPS between December 2004 and June 2012 were included. Patients were classified as the early and converted TIPS groups. Indications, TIPS‐related complications, post‐TIPS hepatic encephalopathy, shunt dysfunction and death were reported.

Results

Of 51 patients included, 39 underwent percutaneous recanalization for 1024 days (0–4574) before TIPS. Early TIPS group (n = 19) has a shorter history of BCS and a lower proportion of prior percutaneous recanalization than converted TIPS group (n = 32). Main indications were diffuse obstruction of three HVs (n = 12), liver failure (n = 2), liver function deterioration (n = 8), refractory ascites (n = 10) and variceal bleeding (n = 19). Procedure‐related intraperitoneal bleeding was reversible in three patients. The cumulative 1‐year rate of being free of first episode of post‐TIPS hepatic encephalopathy and shunt dysfunction was 78.38 and 61.69% respectively. The cumulative 1‐, 2‐, and 3‐year survival rates were 83.82, 81.20 and 76.93% respectively. BCS‐TIPS score, but not Child–Pugh, MELD, Clichy or Rotterdam score, could predict the survival. Age, total bilirubin and inferior vena cava thrombosis were also significantly associated with overall survival. Survival was similar between early and converted TIPS groups.

Conclusions

TIPS can achieve an excellent survival in Chinese patients in whom percutaneous recanalization is ineffective or inappropriate. BCS‐TIPS score could effectively predict these patients' survival.
Poststructuralist Theory and Sociolinguistics: Mapping the Linguistic Turn in Social Theory
Authors: Carter Phillip M.
Published: November 2013

Poststructuralist theory has been broadly influential throughout the humanities and social sciences for two decades, yet sociolinguistic engagement with poststructuralism has been limited to select subfields. In this paper, I consider the possibilities for richer cross‐disciplinary work involving sociolinguistics and poststructuralist social theory. I begin by describing the place of social theory within sociolinguistics, paying attention both to the possibilities of interdisciplinarity and the resistance to it. I then introduce the basic tenets of poststructuralism, focusing primarily on its two main constructs, ‘performativity’ and ‘discourse,’ and briefly discuss the discontentment with structuralism that resulted in ‘the linguistic turn’. I outline the sites in the literature where sociolinguists have already made use of poststructuralist approaches, and conclude by suggesting new possibilities for cross‐disciplinary collaboration. Though the paper focuses primarily on variationist sociolinguistics in the U.S. academy, I also make reference to other fields that work with non‐static, anti‐essentialist approaches to sociality, such as critical discourse analysis. I contend that poststructuralist approaches to social theory are useful for sociolinguists, especially variationists, in that they resist the false dichotomy between agency and structure and provide a comprehensive way of thinking about identity that ignores neither practice nor subjectivity.
Load‐sensitive coupling of proton translocation and torque generation in the bacterial flagellar motor
Authors: Che Yong‐Suk , Nakamura Shuichi , Morimoto Yusuke V. , Kami‐ike Nobunori , Namba Keiichi , Minamino Tohru
Published: November 2013

The Salmonella flagellar motor consists of a rotor and about a dozen stator elements. Each stator element, consisting of MotA and MotB, acts as a proton channel to couple proton flow with torque generation. A highly conserved Asp33 residue of MotB is directly involved in the energy coupling mechanism, but it remains unknown how it carries out this function. Here, we show that the MotB(D33E) mutation dramatically alters motor performance in response to changes in external load. Rotation speeds of the MotA/B(D33E) and MotA(V35F)/B(D33E) motors were markedly slower than the wild‐type motor and fluctuated considerably at low load but not at high load, whereas the rotation rate of the wild‐type motor was stable at any load. At low load, pausing events were frequently observed in both mutant motors. The proton conductivities of these mutant stator channels in their ‘unplugged’ forms were only half of the conductivity of the wild‐type channel. These results suggest that the D33E mutation induces a load‐dependent inactivation of the MotA/B complex. We propose that the stator element is a load‐sensitive proton channel that efficiently couples proton translocation with torque generation and that Asp33 of MotB is critical for this co‐ordinated proton translocation.
Knowledge‐How and Epistemic Luck
Authors: Carter J. Adam , Pritchard Duncan
Published: November 2013

Reductive intellectualists (e.g., Stanley & Williamson 2001; Stanley 2011a; 2011b; Brogaard 2008b; 2009; 2011) hold that knowledge‐how is a kind of knowledge‐that. For this thesis to hold water, it is obviously important that knowledge‐how and knowledge‐that have the same epistemic properties. In particular, knowledge‐how ought to be compatible with epistemic luck to the same extent as knowledge‐that. It is argued,contrareductive intellectualism, that knowledge‐how is compatible with a species of epistemic luck which is not compatible with knowledge‐that, and thus it is claimed that knowledge‐how and knowledge‐that come apart.
De novo assembly of maritime pine transcriptome: implications for forest breeding and biotechnology
Authors: Canales Javier , Bautista Rocio , Label Philippe , Gómez‐Maldonado Josefa , Lesur Isabelle , Fernández‐Pozo Noe , Rueda‐López Marina , Guerrero‐Fernández Dario , Castro‐Rodríguez Vanessa , Benzekri Hicham , Cañas Rafael A. , Guevara María‐Angeles , Rodrigues Andreia , Seoane Pedro , Teyssier Caroline , Morel Alexandre , Ehrenmann François , Le Provost Grégoire , Lalanne Céline , Noirot Céline , Klopp Christophe , Reymond Isabelle , García‐Gutiérrez Angel , Trontin Jean‐François , Lelu‐Walter Marie‐Anne , Miguel Celia , Cervera María Teresa , Cantón Francisco R. , Plomion Christophe , Harvengt Luc , Avila Concepción , Gonzalo Claros M. , Cánovas Francisco M.
Published: November 2013

Maritime pine (Pinus pinasterAit.) is a widely distributed conifer species in Southwestern Europe and one of the most advanced models for conifer research. In the current work, comprehensive characterization of the maritime pine transcriptome was performed using a combination of two different next‐generation sequencing platforms, 454 and Illumina. De novo assembly of the transcriptome provided a catalogue of 26 020 unique transcripts in maritime pine trees and a collection of 9641 full‐length cDNAs. Quality of the transcriptome assembly was validated by RT‐PCR amplification of selected transcripts for structural and regulatory genes. Transcription factors and enzyme‐encoding transcripts were annotated. Furthermore, the available sequencing data permitted the identification of polymorphisms and the establishment of robust single nucleotide polymorphism (SNP) and simple‐sequence repeat (SSR) databases for genotyping applications and integration of translational genomics in maritime pine breeding programmes. All our data are freely available at SustainpineDB, the P. pinaster expressional database. Results reported here on the maritime pine transcriptome represent a valuable resource for future basic and applied studies on this ecological and economically important pine species.
Partner preferences across sexual orientations and biological sex
Authors: WILLIS JARRYD T.
Published: November 2013

This study examined how partner preferences differ across interpersonal contexts (romantic attachment and relationship expectations) based on sexuality and biological sex. Participants completed measures of attachment and behavioral expectations for their romantic partners, cross‐sex friends, and same‐sex friends. The attachment anxiety results revealed an effect of sexuality: Single heterosexuals scored higher for their cross‐sex friends than same‐sex friends, single lesbian/gay individuals scored higher for same‐sex friends than cross‐sex friends, and bisexuals' attachment anxiety was equal regardless of friends' biological sex. The behavioral expectation results revealed an effect of biological sex indicating that, regardless of sexuality, women are preferred over men for emotional/social needs. Finally, an interaction revealed that lesbians have higher expectations for their girlfriends/wives than straight men have for theirs.
Puccinia psidii in Queensland, Australia: disease symptoms, distribution and impact
Authors: Pegg G. S. , Giblin F. R. , McTaggart A. R. , Guymer G. P. , Taylor H. , Ireland K. B. , Shivas R. G. , Perry S.
Published: November 2013

Puccinia psidii has long been considered a significant threat to Australian plant industries and ecosystems. In April 2010, P. psidii was detected for the first time in Australia on the central coast of New South Wales (NSW). The fungus spread rapidly along the east coast and in December 2010 was found in Queensland (Qld) followed by Victoria a year later. Puccinia psidii was initially restricted to the southeastern part of Qld but spread as far north as Mossman. In Qld, 48 species of Myrtaceae are considered highly or extremely susceptible to the disease. The impact of P. psidii on individual trees and shrubs has ranged from minor leaf spots, foliage, stem and branch dieback to reduced fecundity. Tree death, as a result of repeated infection, has been recorded for Rhodomyrtus psidioides. Rust infection has also been recorded on flower buds, flowers and fruits of 28 host species. Morphological and molecular characteristics were used to confirm the identification of P. psidii from a range of Myrtaceae in Qld and compared with isolates from NSW and overseas. A reconstructed phylogeny based on the LSU and SSU regions of rDNA did not resolve the familial placement of P. psidii, but indicated that it does not belong to the Pucciniaceae. Uredo rangelii was found to be con‐specific with all isolates of P. psidii in morphology, ITS and LSU sequence data, and host range.
Turning on the microscope turret: a new view for the study of brassinosteroid signaling in plant development
Authors: Fàbregas Norma , Caño‐Delgado Ana I.
Published: November 2013

Brassinosteroid (BR) hormones are essential for plant growth and development. In Arabidopsis, the general understanding of BR signaling has been greatly attained by genetic and biochemical approaches that led to the identification of central BR signaling components, from the BRI1 receptor at the plasma membrane to downstream acting BR‐regulated BRZ1 and BES1 transcription factors in the nuclei. Recently, an emerging trend is being established to further advance our understanding of the BR signaling pathway in plant development. Scientists have turned on the microscope lens turret to revisit the pleiotropic phenotypes of the BR mutants at a higher magnification, uncovering novel and specific cellular defects in the plant. In‐depth phenotypic analysis in combination with the search for cell‐specific signaling components that are responsible for those particular defects in the mutants are leading to: (1) definition of novel roles for BRs in vascular development, (2) unraveling BR function in cell division through quantitative analysis of Arabidopsis root growth, (3) establishment of a molecular connection between known patterning and BR‐signaling components in organ boundary and stomata development and (4) development of novel strategies toward the identification of BR signaling components with spatiotemporal resolution. In this review, we highlight the importance of these emerging studies to investigate the spatiotemporal control of BR pathways in plant development.
Matrix‐rich and associated matrix‐poor sandstones: Avulsion splays in slope and basin‐floor strata
Authors: Terlaky Viktor , Arnott Robert William Charles
Published: November 2013

A common facies observed in deep‐water slope and especially basin‐floor rocks of the Neoproterozoic Windermere Supergroup (British Columbia, Canada) is structureless, coarse‐tail graded, medium‐grained to coarse‐grained sandstone with from 30% to >50% mud matrix content (i.e. matrix‐rich). Bed contacts are commonly sharp, flat and loaded. Matrix‐rich sandstone beds typically form laterally continuous units that are up to several metres thick and several tens to hundreds of metres wide, and commonly adjacent to units of comparatively matrix‐poor, scour‐based sandstone beds with large tabular mudstone and sandstone clasts. Matrix‐rich units are common in proximal basin‐floor (Upper Kaza Group) deposits, but occur also in more distal basin‐floor (Middle Kaza Group) and slope (Isaac Formation) deposits. Regardless of stratigraphic setting, matrix‐rich units typically are directly and abruptly overlain by architectural elements comprising matrix‐poor coarse sandstone (i.e. channels and splays). Despite a number of similarities with previously described matrix‐rich beds in the literature, for example slurry beds, linked debrites and co‐genetic turbidites, a number of important differences exist, including the stratal make‐up of individual beds (for example, the lack of a clean sandstone turbidite base) and their stratigraphic occurrence (present throughout base of slope and basin‐floor strata, but most common in proximal lobe deposits) and accordingly suggest a different mode of emplacement. The matrix‐rich, poorly sorted nature of the beds and the abundance and size of tabular clasts in laterally equivalent sandstones imply intense upstream scouring, most probably related to significant erosion by an energetic plane‐wall jet or within a submerged hydraulic jump. Rapid energy loss coupled with rapid charging of the flow with fine‐grained sediment probably changed the rheology of the flow and promoted deposition along the margins of the jet. Moreover, these distinctive matrix‐rich strata are interpreted to represent the energetic initiation of the local sedimentary system, most probably caused by a local upflow avulsion.
An Efficient Technique for Surface Strain Recovery from Photogrammetric Data using Meshless Interpolation
Authors: Godinho L. , Dias‐da‐Costa D. , Valença J. , Areias P.
Published: November 2013

In recent years, techniques for monitoring displacements and surface strains in laboratorial tests have been introduced. Some of those methods are based on photogrammetry and image post‐processing, allowing both displacement and strain fields to be monitored at a significant number of target points at any stage.

This manuscript aims at contributing by proposing a simple and comprehensive approach for monitoring experimental tests using photogrammetry. An innovative strategy is introduced to efficiently recover the strain fields at the surface of a loaded specimen. This technique is based on a meshless approach and does not require any triangulation of data points. In this approach, shape functions are constructed from radial basis function interpolation in local subdomains, for which different numbers of data points may be included. To allow accounting for the presence of generic geometries, which may include concavities or convexities, the selection of interpolating points is performed considering a line‐of‐sight algorithm, avoiding inappropriate selection of neighbouring points.

A number of practical examples are here presented for different concrete specimens tested in the laboratory. The presented results indicate that the proposed method can provide smooth strain fields, which allow an easy identification of microcracking development at early stages of loading.
Quantum Walks in Brain Microtubules—A Biomolecular Basis for Quantum Cognition?
Authors: Hameroff Stuart
Published: November 2013

Cognitive decisions are best described by quantum mathematics. Do quantum information devices operate in the brain? What would they look like? Fuss and Navarro (2013) describe quantum lattice registers in which quantum superpositioned pathways interact (compute/integrate) as ‘quantum walks’ akin to Feynman's path integral in a lattice (e.g. the ‘Feynman quantum chessboard’). Simultaneous alternate pathways eventually reduce (collapse), selecting one particular pathway in a cognitive decision, or choice. This paper describes how quantum walks in a Feynman chessboard are conceptually identical to ‘topological qubits’ in brain neuronal microtubules, as described in the Penrose‐Hameroff 'Orch OR' theory of consciousness.
β‐Catenin transcriptional activity is minimal in canine osteosarcoma and its targeted inhibition results in minimal changes to cell line behaviour
Authors: Piskun Caroline M. , Stein Timothy J.
Published: November 2013

Canine osteosarcoma (OS) is an aggressive malignancy associated with poor outcomes. Therapeutic improvements are likely to develop from an improved understanding of signalling pathways contributing to OS development and progression. The Wnt signalling pathway is of interest for its role in osteoblast differentiation, its dysregulation in numerous cancer types, and the relative frequency of cytoplasmic accumulation of β‐catenin in canine OS. This study aimed to determine the biological impact of inhibiting canonical Wnt signalling in canine OS, by utilizing either β‐catenin siRNA or a dominant‐negative T‐cell factor (TCF) construct. There were no consistent, significant changes in cell line behaviour with either method compared to parental cell lines. Interestingly, β‐catenin transcriptional activity was three‐fold higher in normal canine primary osteoblasts compared to canine OS cell lines. These results suggest canonical Wnt signalling is minimally active in canine OS and its targeted inhibition is not a relevant therapeutic strategy.
Genetic screening for PRA‐associated mutations in multiple dog breeds shows that PRA is heterogeneous within and between breeds
Authors: Downs Louise M. , Hitti Rebekkah , Pregnolato Silvia , Mellersh Cathryn S.
Published: November 2013

Objective

To assess the extent of progressive retinal atrophy (PRA) genetic heterogeneity within and between domestic dog breeds.

Methods

DNA from 231 dogs with PRA, representing 36 breeds, was screened for 17 mutations previously associated with PRA in at least one breed of dog. Screening methods included amplified fragment size discrimination using gel electrophoresis or detection of fluorescence, (TaqMan®; Life Technologies, Carlsbad, CA, USA) allelic discrimination, and Sanger sequencing.

Results

Of the 231 dogs screened, 129 were homozygous for a PRA‐associated mutation, 29 dogs were carriers, and 73 were homozygous for the wild‐type allele at all loci tested. In two of the 129 dogs, homozygous mutations were identified that had not previously been observed in the respective breeds: one Chinese Crested dog was homozygous for the RCD3‐associated mutation usually found in the Cardigan Welsh Corgi, and one Standard Poodle was homozygous for the RCD4‐associated mutation previously reported to segregate in Gordon and Irish Setters. In the majority of the breeds (15/21) in which a PRA‐associated mutation is known to segregate, cases were identified that did not carry any of the known PRA‐associated mutations.

Conclusion

Progressive retinal atrophy in the dog displays significant genetic heterogeneity within as well as between breeds. There are also several instances where PRA‐associated mutations segregate among breeds with no known close ancestry.
Theoretical and Experimental Investigation on Tip Forces and Temperature Distributions of the Brush Seal Coupled Aerodynamic Force
Authors: Huang Shouqing , Suo Shuangfu , Li Yongjian , Wang Yuming
Published: November 2013

Based on a type of three-dimensional slice model of a brush seal combined with the commercial CFD software FLUENT, the study calculated the leakage flow of the brush seal. The aerodynamic forces applied on upstream and downstream bristles are analyzed and reduced to a smaller amount of point forces for analysis convenience. The frictional coefficient between the bristle material Haynes 25 and rotor material 1Cr14Mn14Ni are tested. Tip forces including normal reaction and frictional forces caused by aerodynamic forces are quantitatively investigated under conditions with and without frictions using the torque balance principle and nonlinear beam theory (by ANSYS simulations), respectively. Torques, frictional heats, and the temperature distributions of the rotor and bristle pack are studied further. Details and characteristics of the flow and temperature distributions inside the bristle pack are presented. In the experiments, besides traditional tests, such as leakage and torque tests, an infrared camera is employed to capture temperature distributions at the interface of the rotor, bristle pack and nearby zones under various pressure differentials and rotation speeds. The three-dimensional slice model is firstly verified by calculating the leakages, torques and temperature distributions of the brush seal and confirmed via experimentation. The influence of various frictional coefficients and pressure differentials on tip forces, torque and temperature distributions are also examined.
Hybrid modeling of time-dependent rarefied gas expansion
Authors: Vargas Manuel , Naris Steryios , Valougeorgis Dimitris , Pantazis Sarantis , Jousten Karl
Published: November 2013

The time evolution of the flow parameters in a system where gas is expanded from a high pressure chamber through a tube toward a low pressure chamber is investigated. During the process, the pressure in the two chambers is changing in the opposite direction, while the flow rate is reduced until the system reaches its equilibrium state. Rarefied conditions may be present. Based on the observation that the characteristic time in the chambers is several orders of magnitude larger than that in the tube, the evolution of the flow is modeled in a hybrid manner. At each time step, based on kinetic theory, a steady-state flow configuration is solved to estimate the amount of gas passing through the tube (micromodel) and then the pressure of the two vessels is updated by applying the mass conservation principle and the equation of state (macromodel). The pressure and the flow rate variation with respect to time are provided for several time-dependent configurations and the dependency of the results on the initial Knudsen number and pressure ratio as well as on the length of the tube is analyzed. The proposed methodology, which is applicable when the volume of the chambers is significantly larger than the volume of the tube, is valid in the whole range of the Knudsen number and computationally very efficient.
Growth mode evolution of hafnium oxide by atomic layer deposition
Authors: Nie Xianglong , Ma Fei , Ma Dayan , Xu Kewei
Published: November 2013

HfO2 thin films were deposited using tetrakis-ethylmethylamido hafnium and H2O as precursors on silicon by atomic layer deposition (ALD). The morphology and microstructures at different ALD cycles were characterized by atomic force microscopy and high-resolution transmission electron microscopy. Based on the height–height correlation function and power spectral density function, quantitative analysis of surface morphologies was performed. Three characteristic dimensions (ξ1, ξ2, and ξ3) corresponding to three surface structures, islands, local and global fluctuations, were identified. The evolution of ALD growth mode at range of the three critical scales was investigated, respectively. It suggests the transformation of growth mode from quasi two-dimensional layer-by-layer to three-dimensional island for global fluctuations.
Young's double-slit experiment with single photons and quantum eraser
Authors: Rueckner Wolfgang , Peidle Joseph
Published: November 2013

An apparatus for a double-slit interference experiment in the single-photon regime is described. The apparatus includes a which-path marker that destroys the interference as well as a quantum eraser that restores it. We present data taken with several light sources, coherent and incoherent and discuss the efficacy of these as sources of single photons.
Simultaneous Stark and Zeeman effects in atoms with hyperfine structure
Authors: Virgo Wilton L.
Published: November 2013

A quantum model for calculating the combined Stark and Zeeman effects of simultaneously applied electric and magnetic fields is presented. Our focus here is on atoms with hyperfine structure, such as Cesium. Matrix representations of the Stark, Zeeman, and hyperfine interaction operators are constructed using angular momentum theory and spherical tensor algebra. Matrix elements are evaluated in order to determine the energy-level dependence on the applied fields and reveal intriguing state dynamics in both parallel and orthogonal electric and magnetic fields. The fundamental physics is relevant for an advanced undergraduate or graduate quantum mechanics course.
The Intestinal Microbiota Modulates the Anticancer Immune Effects of Cyclophosphamide
Authors: Viaud Sophie , Saccheri Fabiana , Mignot Grégoire , Yamazaki Takahiro , Daillère Romain , Hannani Dalil , Enot David P. , Pfirschke Christina , Engblom Camilla , Pittet Mikael J. , Schlitzer Andreas , Ginhoux Florent , Apetoh Lionel , Chachaty Elisabeth , Woerther Paul-Louis , Eberl Gérard , Bérard Marion , Ecobichon Chantal , Clermont Dominique , Bizet Chantal , Gaboriau-Routhiau Valérie , Cerf-Bensussan Nadine , Opolon Paule , Yessaad Nadia , Vivier Eric , Ryffel Bernhard , Elson Charles O. , Doré Joël , Kroemer Guido , Lepage Patricia , Boneca Ivo Gomperts , Ghiringhelli François , Zitvogel Laurence
Published: November 2013

The Microbiota Makes for Good Therapy

The gut microbiota has been implicated in the development of some cancers, such as colorectal cancer, but—given the important role our intestinal habitants play in metabolism—they may also modulate the efficacy of certain cancer therapeutics.

Iida
et al.

(p.
967
) evaluated the impact of the microbiota on the efficacy of an immunotherapy [CpG (the cytosine, guanosine, phosphodiester link) oligonucleotides] and oxaliplatin, a platinum compound used as a chemotherapeutic. Both therapies were reduced in efficacy in tumor-bearing mice that lacked microbiota, with the microbiota important for activating the innate immune response against the tumors.

Viaud
et al.

(p.
971
) found a similar effect of the microbiota on tumor-bearing mice treated with cyclophosphamide, but in this case it appeared that the microbiota promoted an adaptive immune response against the tumors.
Defining Stem Cell Dynamics in Models of Intestinal Tumor Initiation
Authors: Vermeulen Louis , Morrissey Edward , van der Heijden Maartje , Nicholson Anna M. , Sottoriva Andrea , Buczacki Simon , Kemp Richard , Tavaré Simon , Winton Douglas J.
Published: November 2013

Limiting Tumor Initiation

What is the competitive advantage of cells with frequently occurring mutations during tumor development?Vermeulenet al.(p.995; see the Perspective byBozic and Nowak) quantified the advantages ofApc-loss,Krasactivation, andP53mutation during tumor initiation in the mouse intestine. The mutations conferred only a limited clonal advantage. Indeed, many mutated stem cells were stochastically replaced by wild-type stem cells, helping to limit tumor initiation.
Bridge or Crutch?
Authors: McNutt Marcia
Published: November 2013

Last week, the U.S. Energy Information Administration (EIA) reported that the country produced more crude oil than it imported for the first time in two decades.
*
Over the past 5 years, the United States has reduced its dependence on imported oil by nearly 50%, largely through the use of hydraulic fracturing (“hydrofracking”) to tap into oil resources in shale rock in the northern Great Plains. The United States is now also the world leader in shale gas production: 39% of domestic gas supplies are derived from this unconventional resource.
†
Although this change in the nation's energy portfolio is welcome news, scientists and policy-makers need to be wary of complacency.
Humans Fueled Global Warming Millennia Ago
Authors: Kerr Richard A.
Published: November 2013

Methane from rice farming drove greenhouse warming beginning 5000 years ago.
Physicists Snare a Precious Few Neutrinos From the Cosmos
Authors: Cho Adrian
Published: November 2013

IceCube, a gigantic particle detector built into the ice at the South Pole, has detected neutrinos from beyond our solar system.
Prevalence and Molecular Characterization of Pertactin-Deficient Bordetella pertussis in the United States
Authors: Pawloski L. C. , Queenan A. M. , Cassiday P. K. , Lynch A. S. , Harrison M. J. , Shang W. , Williams M. M. , Bowden K. E. , Burgos-Rivera B. , Qin X. , Messonnier N. , Tondella M. L.
Published: November 2013

Pertussis has shown a striking resurgence in the United States, with a return to record numbers of reported cases as last observed in the 1950s.Bordetella pertussisisolates lacking pertactin, a key antigen component of the acellular pertussis vaccine, have been observed, suggesting thatB. pertussisis losing pertactin in response to vaccine immunity. Screening of 1,300 isolates from outbreak and surveillance studies (historical isolates collected from 1935 up to 2009, isolates from the 2010 California pertussis outbreak, U.S. isolates from routine surveillance between 2010-2012, and isolates from the 2012 Washington pertussis outbreak) by conventional PCR and later by Western blotting andprnsequencing analyses ultimately identified 306 pertactin-deficient isolates. Of these pertactin-deficient strains, 276 were identified as having an IS481in theprngene (prnIS481positive). The firstprnIS481-positive isolate was found in 1994, and the nextprnIS481-positive isolates were not detected until 2010. The prevalence of pertactin-deficient isolates increased substantially to more than 50% of collected isolates in 2012. Sequence analysis of pertactin-deficient isolates revealed various types of mutations in theprngene, including two deletions, single nucleotide substitutions resulting in a stop codon, an inversion in the promoter, and a single nucleotide insertion resulting in a frameshift mutation. All but one mutation type were found inprn2 alleles. CDC 013 was a predominant pulsed-field gel electrophoresis (PFGE) profile in the pertactin-positive isolates (203/994) but was found in only 5% (16/306) of the pertactin-deficient isolates. Interestingly, PFGE profiles CDC 002 and CDC 237 represented 55% (167/306) of the identified pertactin-deficient isolates. These results indicate that there has been a recent dramatic increase in pertactin-deficientB. pertussisisolates throughout the United States.
Cryo-Electron Microscopy Reconstruction Shows Poliovirus 135S Particles Poised for Membrane Interaction and RNA Release
Authors: Butan Carmen , Filman David J. , Hogle James M.
Published: November 2013

During infection, binding of mature poliovirus to cell surface receptors induces an irreversible expansion of the capsid, to form an infectious cell-entry intermediate particle that sediments at 135S. In these expanded virions, the major capsid proteins (VP1 to VP3) adopt an altered icosahedral arrangement to open holes in the capsid at 2-fold and quasi-3-fold axes, and internal polypeptides VP4 and the N terminus of VP1, which can bind membranes, become externalized. Cryo-electron microscopy images for 117,330 particles were collected using Leginon and reconstructed using FREALIGN. Improved rigid-body positioning of major capsid proteins established reliably which polypeptide segments become disordered or rearranged. The virus-to-135S transition includes expansion of 4%, rearrangements of the GH loops of VP3 and VP1, and disordering of C-terminal extensions of VP1 and VP2. The N terminus of VP1 rearranges to become externalized near its quasi-3-fold exit, binds to rearranged GH loops of VP3 and VP1, and attaches to the top surface of VP2. These details improve our understanding of subsequent stages of infection, including endocytosis and RNA transfer into the cytoplasm.
Hypervariable Region 1 Deletion and Required Adaptive Envelope Mutations Confer Decreased Dependency on Scavenger Receptor Class B Type I and Low-Density Lipoprotein Receptor for Hepatitis C Virus
Authors: Prentoe Jannick , Serre Stéphanie B. N. , Ramirez Santseharay , Nicosia Alfredo , Gottwein Judith M. , Bukh Jens
Published: November 2013

Hypervariable region 1 (HVR1) of envelope protein 2 (E2) of hepatitis C virus (HCV) serves important yet undefined roles in the viral life cycle. We previously showed that the viability of HVR1-deleted JFH1-based recombinants with Core-NS2 of H77 (H77
ΔHVR1
, genotype 1a) and S52 (S52
ΔHVR1
, genotype 3a) in Huh7.5 cells was rescued by E2 substitutions N476D/S733F and an E1 substitution, A369V, respectively; HVR1-deleted J6 (J6
ΔHVR1
, genotype 2a) was fully viable. In single-cycle production assays, where HCV RNA was transfected into entry-deficient Huh7-derived S29 cells with low CD81 expression, we found no effect of HVR1 deletion on replication or particle release for H77 and S52. HCV pseudoparticle assays in Huh7.5 cells showed that HVR1 deletion decreased entry by 20- to 100-fold for H77, J6, and S52; N476D/S733F restored entry for H77
ΔHVR1
, while A369V further impaired S52
ΔHVR1
entry. We investigated receptor usage by antibody blocking and receptor silencing in Huh7.5 cells, followed by inoculation of parental and HVR1-deleted HCV recombinants. Compared to parental viruses, scavenger receptor class B type I (SR-BI) dependency was decreased for H77
ΔHVR1/N476D/S733F
, H77
N476D/S733F
, S52
ΔHVR1/A369V
, and S52
A369V
, but not for J6
ΔHVR1
. Low-density lipoprotein receptor (LDLr) dependency was decreased for HVR1-deleted viruses, but not for H77
N476D/S733F
and S52
A369V
. Soluble LDLr neutralization revealed strong inhibition of parental HCV but limited effect against HVR1-deleted viruses. Apolipoprotein E (ApoE)-specific HCV neutralization was similar for H77, J6, and S52 viruses with and without HVR1. In conclusion, HVR1 and HVR1-related adaptive envelope mutations appeared to be involved in LDLr and SR-BI dependency, respectively. Also, LDLr served ApoE-independent but HVR1-dependent functions in HCV entry.
Newly Identified Phosphorylation Site in the Vesicular Stomatitis Virus P Protein Is Required for Viral RNA Synthesis
Authors: Mondal Arindam , Victor Ken G. , Pudupakam R. S. , Lyons Charles E. , Wertz Gail W.
Published: November 2013

The vesicular stomatitis virus (VSV) RNA-dependent RNA polymerase consists of two viral proteins; the large (L) protein is the main catalytic subunit, and the phosphoprotein (P) is an essential cofactor for polymerase function. The P protein interacts with the L protein and the N-RNA template, thus connecting the polymerase to the template. P protein also binds to free N protein to maintain it in a soluble, encapsidation-competent form. Previously, five sites of phosphorylation were identified on the P protein and these sites were reported to be differentially important for mRNA synthesis or genomic replication. The previous studies were carried out by biochemical analysis of portions of the authentic viral P protein or by analysis of bacterium-expressed, exogenously phosphorylated P protein by mutagenesis. However, there has been no systematic biochemical search for phosphorylation sites on authentic, virus-expressed P protein. In this study, we analyzed the P protein isolated from VSV-infected cells for sites of phosphorylation by mass spectrometry. We report the identification of Tyr14 as a previously unidentified phosphorylation site of VSV P and show that it is essential for viral transcription and replication. However, our mass spectral analysis failed to observe the phosphorylation of previously reported C-terminal residues Ser226 and Ser227 and mutagenic analyses did not demonstrate a role for these sites in RNA synthesis.
Efficient Infection of a Human B Cell Line with Cell-Free Kaposi's Sarcoma-Associated Herpesvirus
Authors: Dollery Stephen J. , Santiago-Crespo Rey J. , Kardava Lela , Moir Susan , Berger Edward A.
Published: November 2013

Kaposi's sarcoma-associated herpesvirus (KSHV) is causatively linked to two B cell lymphoproliferative disorders, multicentric Castleman's disease and primary effusion lymphoma. Latently infected B cells are a major KSHV reservoir, and virus activation from tonsillar B cells can result in salivary shedding and virus transmission. Paradoxically, human B cells (primary and continuous) are notoriously refractory to infection, thus posing a major obstacle to the study of KSHV in this cell type. By performing a strategic search of human B cell lymphoma lines, we found that MC116 cells were efficiently infected by cell-free KSHV. Upon exposure to recombinant KSHV.219, enhanced green fluorescent protein reporter expression was detected in 17 to 20% of MC116 cells. Latent-phase transcription and protein synthesis were detected by reverse transcription-PCR and detection of latency-associated nuclear antigen expression, respectively, in cell lysates and individual cells. Selection based on the puromycin resistance gene in KSHV.219 yielded cultures with all cells infected. After repeated passaging of the selected KSHV-infected cells without puromycin, latent KSHV was maintained in a small fraction of cells. Infected MC116 cells could be induced into lytic phase with histone deacetylase inhibitors, as is known for latently infected non-B cell lines, and also selectively by the B cell-specific pathway involving B cell receptor cross-linking. Lytic-phase transition was documented by red fluorescent protein reporter expression, late structural glycoprotein (K8.1A, gH) detection, and infectious KSHV production. MC116 cells were CD27−/CD10+, characteristic of transitional B cells. These findings represent an important step in the establishment of an efficient continuous B cell line model to study the biologically relevant steps of KSHV infection.

IMPORTANCEKaposi's sarcoma-associated herpesvirus (KSHV) causes two serious pathologies of B cells, the antibody-producing cells of the immune system. B cells are a major reservoir for KSHV persistence in the body. Paradoxically, in the laboratory, B cells are extremely difficult to infect with KSHV; this problem greatly hinders scientific analysis of B cell infection. We describe our search for and successful identification of a stable human B cell line that can be efficiently infected by KSHV. Upon infection of these cells, the virus goes into a quiet latent phase, a characteristic feature of many herpesvirus infections. The virus can be triggered to enter an active lytic phase by treatments known to stimulate normal B cell functions. These findings suggest that the new B cell line will be a valuable model in which to study KSHV infection of this major target cell type.