bluuebunny/crossref_metadata_2025 huggingface dataset:
Geography and Economic Preferences as Cultural Markers in a Border Town: The Faunal Remains from Tel Beth‐Shemesh, Israel
Authors: Tamar K. , Bar‐Oz G. , Bunimovitz S. , Lederman Z. , Dayan T.
Published: March 2013

We present a zooarchaeological analysis of the faunal remains at Tel Beth‐Shemesh, a site located in the Shephelah region of Israel, which has been dated to the Late Bronze Age and Iron Age I. The site, identified as the biblical city of Beth‐Shemesh, was a Canaanite border town between Philistine and Israelite settlements and of great importance in our attempts to understand the social and cultural transformations that occurred in the southern Levant during those periods. This study contributes to a more accurate understanding of the cultural identity of the site's inhabitants by exploring the cultural differences between populations as reflected in their different dietary preferences. We analysed the subsistence economy at the site, the general exploitation patterns, herd management strategies and consumption practices, all of which are based mostly on domestic livestock. We determined the cultural identity at the site mainly by comparing the representation of pig remains with that found at other sites in the region, and offer various explanations for the differences. The comparisonsrevealed clear differences between Tel Beth‐Shemesh and other known nearby Philistine sites. This site appears to have possessed a self‐contained production and consumption economy with similarities in the general pattern of animal exploitation between the two periods. These similarities constitute evidence for the continuation of the local population and of its culture at the site during the period of turmoil that swept the region during the transition to the Iron Age. Copyright © 2013 John Wiley & Sons, Ltd.
Flexibel, leicht und durchsichtig
Authors: Ecker Bernhard
Published: March 2013

Organische Solarzellen basieren auf organischen Halbleitern. Sie eröffnen der Photovoltaik völlig neue Anwendungsgebiete, denn sie lassen sich auf flexible Folien gedruckt in Kleidung integrieren oder semitransparent strukturiert in Fenster einbetten. Inzwischen erreichen die besten organischen Solarzellen Wirkungsgrade über 10 % und befinden sich auf dem Weg zur Kommerzialisierung. Allerdings ist noch Grundlagenforschung erforderlich. Eine Herausforderung ist das effiziente Trennen und Einsammeln der vom Licht erzeugten elektrischen Ladungsträger im Material. Das erfordert eine gezielte Nanostrukturierung der organischen Halbleiterschichten. Weitere Herausforderungen sind die Verbesserung der Lebensdauer sowie die Entwicklung von Herstellungsmethoden, die wenig Energie verbrauchen und die Produktionskosten senken.
Markgräfler Scheibenfeuer
Authors: Nachtigall Werner
Published: March 2013

Das Markgräfler Brauchtum des Scheibenschlagens zur Fasnachtszeit ist nicht nur ein traditionelles Spektakel; es lässt sich auch physikalisch untermauern. Wie hoch sind Startgeschwindigkeit und Startimpuls der Scheibe? Wie wirkt sie als Flugkörper und wie stabilisiert sie ihren Flug? Strömungsmechanische Messungen an Originalscheiben geben darüber Auskunft.
Der Sound der Nanowelt
Authors: Euler Manfred
Published: March 2013

Der Beitrag stellt akustische Modelle der Rastertunnelmikroskopie vor. Diese nutzen Schallwellen und computergenerierte Visualisierungen zur Abbildung akustischer Systeme. Quantenanalogien veranschaulichen abstrakte Konzepte wie den Tunneleffekt und die Zustandsdichten von Elektronen. Die Experimente vermitteln einen praktischen, an Alltagserfahrungen orientierten Zugang zu Konzepten sowie Mess‐ und Visualisierungsmethoden der Nanowissenschaft. Sie demonstrieren auch, wie Nahfeldabbildungen die Beugungsgrenze der konventionellen Mikroskopie überwinden können.
Negative absolute Temperaturen
Authors: Schneider Ulrich
Published: March 2013

Am absoluten Nullpunkt kommt jede klassische, thermische Bewegung zum Erliegen, und nichts kann kälter sein als T = 0 K. Dennoch ist es unserer Gruppe vom Max‐Planck‐Institut für Quantenoptik und der Ludwig‐Maximilians‐Universität München gelungen, negative absolute Temperaturen zu erzeugen. Wie passt das zusammen?
Physikalische Konstanten in Raum und Zeit
Authors: Henkel Christian , Menten Karl
Published: March 2013

Seit einigen Jahrzehnten können durch Messung optischer Spektrallinien in astronomischen Objekten die Größen physikalischer Fundamentalkonstanten bestimmt werden. Bei dem Versuch, immer genauere Daten zu erhalten, erweisen sich seit kurzem Linien interstellarer Moleküle im Radiobereich als besonders geeignet. So konnten wir kürzlich das Proton‐zu‐Elektron‐Massenverhältnis mit bislang unerreichter Präzision im jungen Universum messen und mit dem heutigen Wert vergleichen.
Verräterische Lichtmuster in der Teetasse
Authors: Schlichting H. Joachim
Published: March 2013

Ein senkrecht durch eine dünne Wasserschicht dringender Laserstrahl zeichnet auf dem Boden eines Gefäßes ein strukturiertes Ringsystem. Ursache ist die diffuse Reflexion am Tassenboden.
pH‐sensitive residues in the p19 RNA silencing suppressor protein from carnation Italian ringspot virus affect siRNA binding stability
Authors: Law Sean M. , Zhang Bin W. , Brooks Charles L.
Published: March 2013

Tombusviruses, such as Carnation Italian ringspot virus (CIRV), encode a protein homodimer called p19 that is capable of suppressing RNA silencing in their infected hosts by binding to and sequestering short‐interfering RNA (siRNA) away from the RNA silencing pathway. P19 binding stability has been shown to be sensitive to changes in pH but the specific amino acid residues involved have remained unclear. Using constant pH molecular dynamics simulations, we have identified key pH‐dependent residues that affect CIRV p19–siRNA binding stability at various pH ranges based on calculated changes in the free energy contribution from each titratable residue. At high pH, the deprotonation of Lys60, Lys67, Lys71, and Cys134 has the largest effect on the binding stability. Similarly, deprotonation of several acidic residues (Asp9, Glu12, Asp20, Glu35, and/or Glu41) at low pH results in a decrease in binding stability. At neutral pH, residues Glu17 and His132 provide a small increase in the binding stability and we find that the optimal pH range for siRNA binding is between 7.0 and 10.0. Overall, our findings further inform recent experiments and are in excellent agreement with data on the pH‐dependent binding profile.
Plasma‐assisted molecular beam epitaxy of AlGaN heterostructures for deep‐ultraviolet optically pumped lasers
Authors: Jmerik V. N. , Lutsenko E. V. , Ivanov S. V.
Published: March 2013

The paper reports on elaboration of plasma‐assisted molecular beam epitaxy (MBE) of AlxGa1 − xN‐based quantum‐well (QW) structures with high Al content (up to 50% in the QW) grown directly on c‐sapphire. Different elements of the structure design are considered consecutively in detail along with the advanced growth approaches developed for each element. Special attention is paid to the growth conditions of (i) AlN nucleation layers with suppressed generation of threading dislocations (TDs), (ii) 2‐µm thick AlN buffer layers with atomically smooth droplet‐free morphology (rms = 0.46 nm) grown under the strongly metal‐rich conditions, (iii) cladding and waveguide AlGaN layers also possessing the atomically smooth droplet‐free morphology that is ensured by the accurately established phase diagram of metal(Ga)‐rich growth conditions within the temperature range 660–780 °C. Employing several 3‐nm thick strained GaN insertions in the AlN buffer layer and a AlGaN/AlN superlattice (SL) on top of it is shown to result in a significant decrease of TD's density down to 108–109 cm−2 in the top QW region fabricated by a submonolayer digital alloying (SDA) technique. Finally, advanced AlGaN‐based QW structures are presented, which demonstrate optically pumped lasing within the deep‐ultraviolet (UV) wavelength range with the threshold power density below 600 kW cm−2 (at 289 nm).
Field‐induced quantum criticality – application to magnetic cooling
Authors: Lang Michael , Wolf Bernd , Honecker Andreas , Balents Leon , Tutsch Ulrich , Cong Pham Than , Hofmann Georg , Krüger Natalia , Ritter Franz , Assmus Wolf , Prokofiev Andrey
Published: March 2013

Materials close to a quantum‐critical point – a zero‐temperature phase transition – exhibit anomalous thermodynamic properties also at finite temperatures. Close to a magnetic field‐induced quantum‐critical point, for example, the finite‐temperature entropy ST shows strong variations upon varying the magnetic field. Here we discuss the possibility to use this accumulation of entropy around a field‐induced quantum‐critical point for realizing an efficient magnetic cooling. Our proof‐of‐principle demonstration is based on measurements and theoretical calculations of the magnetocaloric properties of low‐dimensional spin‐1/2 antiferromagnets close to their field‐induced quantum‐critical points. We present results of the magnetocaloric effect ΓB = T−1(∂T/∂B)S ≈ const as a function of both field and temperature in the vicinity of the quantum‐critical point and discuss various performance characteristics, such as range of operation, efficiency and hold time. These figures are compared with those of a state‐of‐the‐art paramagnetic coolant.
Defect‐related visible luminescence of silica nanoparticles
Authors: Vaccaro L. , Spallino L. , Agnello S. , Buscarino G. , Cannas M.
Published: March 2013

We have investigated the visible emission of silica nanoparticles by time‐resolved luminescence spectra. We have characterized the spectroscopic properties of the blue band, centered around 2.8 eV, peculiar of as received samples and we have evidenced the effects induced by high power UV laser irradiation on the emitting defects.

Moreover, the comparison with the luminescence of samples thermochemically treated in controlled atmosphere allows us to critically discuss the structural model proposed in the current literature. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phonon modes and Raman scattering in SixGe1‐x nanocrystals: microscopic modelling
Authors: Vasin A. S. , Vikhrova O. V. , Vasilevskiy M. I.
Published: March 2013

Si1‐xGex nanocrystals (NCs) of different composition and size were generated using the Molecular Dynamics (MD) method by minimizing NC's total energy calculated using Tersoff's empirical potential and applying rigid boundary conditions. The dynamical matrix of the relaxed NC was constructed and the NC phonon modes were calculated. The localisation of the principal (Si‐Si, Si‐Ge and Ge‐Ge) modes is investigated by analysing their inverse participation ratio. The dependence of the corresponding Raman spectra, obtained by employing the bond polarisability model, upon x and the NC size is presented and compared to previous calculated results and available experimental data. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Control of condensation and evaporation of electron–hole liquid in diamond by femtosecond laser pulses
Authors: Kozák Martin , Trojánek František , Popelárˇ Tomáš , Malý Petr
Published: March 2013

We demonstrate the ultrafast control of condensation and evaporation of an electron–hole liquid in diamond prepared by chemical vapor deposition. The electron–hole liquid dynamics was measured using a three‐pulse pump and probe experiment. The transient transmission changes in the presence of electron–hole drops were assigned to the increase in the Drude scattering rate in the model of free carrier absorption due to a high carrier density. The fast (∼1 ps) liquid evaporation was induced by infrared femtosecond pulses and its dynamics was investigated under different photon energies and fluences. The value of the electron–hole liquid binding energy per electron–hole pair 80 ± 40 meV determined from the measured transient transmission signal agrees well with previously published values. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study of IP prefix hijacking in cloud computing networks
Authors: Liu Yujing , Peng Wei , Su Jinshu
Published: March 2013

IP prefix hijacking remains a serious security threat to the traditional services in the Internet. It also harms the confidentiality and integrity of user data in Internet‐enabled cloud services because of its great dependence on Internet routing infrastructure. In addition, collaborations between networks in the cloud environment, especially in cross‐domain deployment, bring about new types of prefix hijacking attack, which may cause greater impact due to side‐effect of the cooperation of victim and infected autonomous systems. It is important to understand what impact a prefix hijacking attack can cause and how the number and locations of participants can affect the attacking results. In this paper, we model this problem as an attack planning task and solve it by applying a genetic algorithm. By analyzing the best solution to the problem, we find that the type of victims plays a more important role in IP prefix hijacking than that of attackers. Attackers can gain great impact even when the prefixes of a small number of victims are hijacked. For attack planning, the degree of an autonomous system is a major criterion to be considered. These findings are useful for securing cloud computing networks by preventing and eliminating IP prefix hijacking attacks. Copyright © 2013 John Wiley & Sons, Ltd.
Verifying cloud service‐level agreement by a third‐party auditor
Authors: Zhang Hongli , Ye Lin , Shi Jiantao , Du Xiaojiang , Guizani Mohsen
Published: March 2013

In this paper, we study the important issue of verifying service‐level agreement (SLA) with an untrusted cloud and present an SLA verification framework that utilizes a third‐party auditor (TPA). A cloud provides users with elastic computing and storage resources in a pay‐as‐you‐go way. An SLA between the cloud and a user is a contract that specifies the computing resources and performances that the cloud should provide to the user. A cloud service provider (CSP) has incentives to cheat on the SLA, for example, providing a user with less central processing unit and memory resources than specified in the SLA, which allows the CSP to support more users and make more profits. A malicious CSP can easily disrupt the existing SLA monitoring/verification techniques by interfering with the monitoring/measurement process. A TPA resolves the trust dilemma between a CSP and its users. Under the TPA framework and the untrusted‐cloud threat model, we design two effective testing algorithms that can detect an SLA violation of the virtual machine memory size. Using real experiments, we demonstrate that our algorithms can detect cloud cheating on a virtual machine's memory size (i.e., SLA violations). Furthermore, we show that our testing algorithms can defend various attacks from a malicious CSP, which tries to hide an SLA violation. Copyright © 2013 John Wiley & Sons, Ltd.
Toward a Lived Science Curriculum in Intersecting Figured Worlds: An Exploration of Individual Meanings in Science Education
Authors: Price Jeremy F. , McNeill Katherine L.
Published: March 2013

As knowledge of and familiarity with science becomes an increasingly important aspect of contemporary life and citizenship, efforts have been made to make the science curriculum a “lived” curriculum (Hurd, 2000), one that reaches out to the lives, communities, and experiences of students. In this research around a high school urban ecology curriculum, we advance the idea that a focus on meaning, as the keystone for identity development, can help reach the goal of a lived science curriculum. Drawing upon social practice theory (Holland & Lave, 2001, 2009) and figured worlds (Holland, Lachicotte, Skinner, & Cain, 1998; Urietta, 2007), we present a way to conceptualize the meanings which emerge. We find through interviews with the adult participants (two curriculum developers and a classroom teacher) and students that meaning is described using three layers: meaning in person, meaning in intent, and meaning in practice. There are points of continuity and discontinuity of these meanings attributed to the curriculum by the adult participants. We further present data through the analysis of classroom video and artifacts created by students during an activity designed to elicit the meanings that students attribute to the curriculum. We discuss these findings and the possibilities for curriculum to provide opportunities for intersecting figured worlds which provide a focus on meaning and opportunities for agency in and with science. © 2013 Wiley Periodicals, Inc. J Res Sci Teach 50: 501–529, 2013.
Mapping extreme snowfalls in the French Alps using max‐stable processes
Authors: Gaume J. , Eckert N. , Chambon G. , Naaim M. , Bel L.
Published: March 2013

Key Points

Analysis of extreme snowfall data using spatial extreme statistics

Mapping of extreme snowfall water equivalent using max‐stable processes

Obtaining return level maps, operational tool for avalanche risk management
Yellowstone grizzly delisting rhetoric: An analysis of the online debate
Authors: Parker Israel D. , Feldpausch‐Parker Andrea M.
Published: March 2013

The Yellowstone ecosystem is a hotbed of environmental issues and conflicts such as endangered species management. The Yellowstone grizzly bear (Ursus arctos horribilis) delisting debate illustrates how rhetoric can contribute to fragmentation and polarization among stakeholders engaged in endangered species conflicts. The partisan view of the grizzly ideograph, and what it represented, created impediments to conflict management (e.g., mistrust and development of and/or belief in stereotypes). The debate coalesced as the U.S. Fish and Wildlife Service began proceedings to delist the Yellowstone population from the endangered species list in 2005. Our objective was to use a rhetorical analysis of the Internet‐based debate to identify strategies used by disputants in conflicts over the Endangered Species Act. By analyzing web‐based stakeholder texts from 1998 through 2009, we found that rhetoric about grizzly bears fell into three main categories of rhetorical appeal: authority, ethics, and identity. Arguments relying on these appeals contributed to destructive communication amongst stakeholders. Rhetorical strategies served to clearly define stakeholder belief systems and clarify exclusionary practices. We found as an emerging theme that perspectives toward climate change influenced perception of grizzly delisting (e.g., climate change influences grizzly bear food availability). The Endangered Species Act's lack of directives regarding anthropogenic climate change further complicated the debate. We demonstrated how rhetorical analyses can reveal disputants' preferred social control frameworks. This provides important information to managers seeking to promote common ground between otherwise conflicted stakeholders that leads to legitimate and lasting policy decisions. © 2013 The Wildlife Society.
Cryptographic protocols with everyday objects
Authors: Heather James , Schneider Steve , Teague Vanessa
Published: March 2013

Most security protocols appearing in the literature make use of cryptographic primitives that assume that the participants have access to some sort of computational device. However, there are times when there is need for a security mechanism to evaluate some result without leaking sensitive information, but computational devices are unavailable. We discuss here various protocols for solving cryptographic problems using everyday objects: coins, dice, cards, and envelopes.
Robotically Assisted Revision of Bariatric Surgeries Is Safe and Effective to Achieve Further Weight Loss
Authors: Snyder Brad , Wilson Todd , Woodruff Vicky , Wilson Erik
Published: March 2013

Background

As more bariatric operations are being performed in the USA every year, the number of revisions has increased. These operations are challenging and have a higher morbidity than the initial operation. We have reviewed our series of robotically assisted revisions.

Methods

At the University of Texas Medical School at Houston, we reviewed robotic revision cases from 2004 through 2011 and found 99 bariatric revisions using robotic assistance. Selected endpoints included body mass index (BMI) at follow‐up, percent excess weight loss (%EWL), complications, intubation time, operative time, and length of hospital stay.

Results

The average BMI at the time of revision was 44.8 kg/m2 and fell to 29 kg/m2 after 3 years. BMI was significantly lower at all time intervals (3, 12, 24, and 36 months) compared to initial BMI (p < 0.001). The %EWL was also significant at 1, 3, 12, 24, and 36 months post‐revision (p < 0.001). There was a 24 % (13/55) 90‐day readmission rate. The overall complication rate was 17 %, with each individual complication rate between 2 and 4 %. There were no deaths. The average operative time was 204 min, and the average length of hospital stay was 2.3 days.

Conclusions

Revising previous bariatric operations to gastric bypass is difficult and time consuming. Although robotically assisted revision can be done safely and can result in effective further weight loss, the high postoperative complication rate is an issue that warrants further attention.
Responses of soil microbial biomass and enzymatic activities to different forms of organic nitrogen deposition in the subtropical forests in East China
Authors: Lü Yanna , Wang Congyan , Jia Yanyan , Du Jingjing , Ma Xu , Wang Wenwen , Pu Gaozhong , Tian Xingjun
Published: March 2013

Numerous studies reported that inorganic nitrogen (N) deposition strongly affected forest ecosystems. However, organic N is also an important component of atmospheric N deposition. The influence of organic N deposition on soil microbial biomass and extracellular enzymatic activities (EEA) in subtropical forests remains unclear. Coniferous forest (CF) and broad‐leaved forest (BF) were chosen from the Zijin Mountain in China. Five forms of organic N (urea, glycine, serine, nonylamine, and a mixture of all four) were used to fertilize the soils in CF and BF every month for 1 year. Soil samples were collected every 2 months. Subsequently, soil microbial biomass and EEA were assayed. Results showed that the microbial biomass and EEA of soils fertilized with urea and amino acids increased significantly, whereas those fertilized with nonylamine and mixed N decreased significantly. Urea and amino acid fertilizations had a more positive influence on EEA of BF than on those of CF. Nonylamine fertilization had a more negative influence on EEA of CF than on those of BF. Organic N fertilization shifted soil microbial biomass away from the excretion of N‐degrading enzymes and toward the excretion of C‐degrading enzymes. These results suggest that organic N type is an important factor that affects soil microbial biomass, EEA, and their relationship. Organic N deposition may seriously affect soil C and N cycling, as well as carbon dioxide releasing from the soils by influencing microbial activities and biomass. This study thereby provides evidence that soil microorganisms have strong feedback to different forms of organic N deposition.
Amaranth Oil Increased Fecal Excretion of Bile Acid but Had No Effect in Reducing Plasma Cholesterol in Hamsters
Authors: de Castro Luíla Ívini Andrade , Soares Rosana Aparecida Manólio , Saldiva Paulo H. N. , Ferrari Roseli A. , Miguel Ana M. R. O. , Almeida Claudia A. S. , Arêas José Alfredo Gomes
Published: March 2013

Hamsters were fed for 4 weeks on four different diets: control (C) (balanced diet containing 20 % corn oil as the lipid source), hypercholesterolemic (H) (identical to C but containing 12 % coconut oil, 8 % corn oil and 0.1 % cholesterol as the lipid source), amaranth oil (A) (identical to H without corn oil but with amaranth oil), and squalene (S) (identical to H but admixed with squalene in the ratio found in amaranth oil). There were no significant differences in lipid profile, and in the cholesterol excreted in the animals' feces from amaranth oil (A) and squalene (S) groups. Fecal excretion of bile acids was greater in the amaranth oil (A) and squalene groups (S) as compared to the other groups. The scores of steatosis and parenchymal inflammation observed in the amaranth oil (A) and squalene groups (S) were superior to the ones observed in the other groups. Our findings demonstrated that amaranth oil, and its component squalene, increased the excretion of bile acids but did not have a hypocholesterolemic effect in hamsters fed on a diet containing high amounts of saturated fat and cholesterol.
Structure-Based Comparative Analysis and Prediction of N-Linked Glycosylation Sites in Evolutionarily Distant Eukaryotes
Authors: Lam Phuc Vinh Nguyen , Goldman Radoslav , Karagiannis Konstantinos , Narsule Tejas , Simonyan Vahan , Soika Valerii , Mazumder Raja
Published: March 2013

The asparagine-X-serine/threonine (NXS/T) motif, where X is any amino acid except proline, is the consensus motif for N-linked glycosylation. Significant numbers of high-resolution crystal structures of glycosylated proteins allow us to carry out structural analysis of the N-linked glycosylation sites (NGS). Our analysis shows that there is enough structural information from diverse glycoproteins to allow the development of rules which can be used to predict NGS. A Python-based tool was developed to investigate asparagines implicated in N-glycosylation in five species: Homo sapiens, Mus musculus, Drosophila melanogaster, Arabidopsis thaliana and Saccharomyces cerevisiae. Our analysis shows that 78% of all asparagines of NXS/T motif involved in N-glycosylation are localized in the loop/turn conformation in the human proteome. Similar distribution was revealed for all the other species examined. Comparative analysis of the occurrence of NXS/T motifs not known to be glycosylated and their reverse sequence (S/TXN) shows a similar distribution across the secondary structural elements, indicating that the NXS/T motif in itself is not biologically relevant. Based on our analysis, we have defined rules to determine NGS. Using machine learning methods based on these rules we can predict with 93% accuracy if a particular site will be glycosylated. If structural information is not available the tool uses structural prediction results resulting in 74% accuracy. The tool was used to identify glycosylation sites in 108 human proteins with structures and 2247 proteins without structures that have acquired NXS/T site/s due to non-synonymous variation. The tool, Structure Feature Analysis Tool (SFAT), is freely available to the public at http://hive.biochemistry.gwu.edu/tools/sfat.
High expression of microRNA‐625‐3p is associated with poor response to first‐line oxaliplatin based treatment of metastatic colorectal cancer
Authors: Rasmussen Mads H. , Jensen Niels F. , Tarpgaard Line S. , Qvortrup Camilla , Rømer Maria U. , Stenvang Jan , Hansen Tine P. , Christensen Lise L. , Lindebjerg Jan , Hansen Flemming , Jensen Benny V. , Hansen Torben F. , Pfeiffer Per , Brünner Nils , Ørntoft Torben F. , Andersen Claus L.
Published: March 2013

The backbone of current cytotoxic treatment of metastatic colorectal cancer (mCRC) consists of a fluoropyrimidine together with either oxaliplatin (XELOX/FOLFOX) or irinotecan (XELIRI/FOLFIRI). With an overall objective response rate of approximately 50% for either treatment combination, a major unsolved problem is that no predictors of response to these treatments are available. To address this issue, we profiled 742 microRNAs in laser‐capture microdissected cancer cells from responding and non‐responding patients receiving XELOX/FOLFOX as first‐line treatment for mCRC, and identified, among others, high expression of miR‐625‐3p, miR‐181b and miR‐27b to be associated with poor clinical response. In a validation cohort of 94 mCRC patients treated first‐line with XELOX, high expression of miR‐625‐3p was confirmed to be associated with poor response (OR = 6.25, 95%CI [1.8; 21.0]). Independent analyses showed that miR‐625‐3p was not dysregulated between normal and cancer samples, nor was its expression associated with recurrence of stage II or III disease, indicating that miR‐625‐3p solely is a response marker. Finally, we also found that these miRNAs were up‐regulated in oxaliplatin resistant HCT116/oxPt (miR‐625‐3p, miR‐181b and miR‐27b) and LoVo/oxPt (miR‐181b) colon cancer cell lines as compared with their isogenic parental cells. Altogether, our results suggest an association between miR‐625‐3p and response to first‐line oxaliplatin based chemotherapy of mCRC.
Quillen's work on formal group laws and complex cobordism theory
Authors: Ravenel Douglas C.
Published: March 2013

In 1969 Quillen discovered a deep connection between complex cobordism and formal group laws which he announced in [Qui69]. Algebraic topology has never been the same since. We will describe the content of [Qui69] and then discuss its impact on the field. This paper is a writeup of a talk on the same topic given at the Quillen Conference at MIT in October 2012. Slides for that talk are available on the author's home page.
Stochastic dynamics and model reduction of amplifier flows: the backward facing step flow
Authors: Dergham G. , Sipp D. , Robinet J.-Ch.
Published: March 2013

Methods for investigating and approximating the linear dynamics of amplifier flows are examined in this paper. The procedures are derived for incompressible flow over a two-dimensional backward-facing step. First, the singular value decomposition of the resolvent is performed over a frequency range in order to identify the optimal and suboptimal harmonic forcing and responses of the flow. These forcing/responses are shown to be organized into two categories: the first accounting for the Orr and Kelvin–Helmholtz instabilities in the shear layer and the second for the advection and diffusion of perturbations in the free stream. Next, we investigate the dynamics of the flow when excited by a white in space and time noise. We compute the predominant patterns of the random flow which optimally account for the sustained variance, the empirical orthogonal functions (EOFs), as well as the predominant forcing structures which optimally contribute to the sustained variance, the stochastic optimals (SOs). The leading EOFs and SOs are expressed as a linear combination of the suboptimal forcing and responses of the flow and are related to particular instability mechanisms and/or frequency intervals. Finally, we use the leading EOFs, SOs and balanced modes (obtained from balanced truncation) to build low-order models of the flow dynamics. These models are shown to accurately recover the time propagator and resolvent of the original dynamical system. In other words, such models capture the entire flow response from any forcing and may be used in the design of efficient closed-loop controllers for amplifier flows.
Steady base states for non-Newtonian granular hydrodynamics
Authors: Vega Reyes Francisco , Santos Andrés , Garzó Vicente
Published: March 2013

We study in this work steady laminar flows in a low-density granular gas modelled as a system of identical smooth hard spheres that collide inelastically. The system is excited by shear and temperature sources at the boundaries, which consist of two infinite parallel walls. Thus, the geometry of the system is the same that yields the planar Fourier and Couette flows in standard gases. We show that it is possible to describe the steady granular flows in this system, even at large inelasticities, by means of a (non-Newtonian) hydrodynamic approach. All five types of Couette–Fourier granular flows are systematically described, identifying the different types of hydrodynamic profiles. Excellent agreement is found between our classification of flows and simulation results. Also, we obtain the corresponding nonlinear transport coefficients by following three independent and complementary methods: (i) an analytical solution obtained from Grad’s 13-moment method applied to the inelastic Boltzmann equation; (ii) a numerical solution of the inelastic Boltzmann equation obtained by means of the direct simulation Monte Carlo method; and (iii) event-driven molecular dynamics simulations. We find that, while Grad’s theory does not describe quantitatively well all transport coefficients, the three procedures yield the same general classification of planar Couette–Fourier flows for the granular gas.
Vortex-induced vibration of a neutrally buoyant tethered sphere
Authors: Lee H. , Hourigan K. , Thompson M. C.
Published: March 2013

A combined numerical and experimental study examining vortex-induced vibration (VIV) of a neutrally buoyant tethered sphere has been undertaken. The study covered the Reynolds-number range $50\leq \mathit{Re}\lesssim 12\hspace{0.167em} 000$, with the numerical ($50\leq \mathit{Re}\leq 800$) and experimental ($370\leqslant \mathit{Re}\lesssim 12\hspace{0.167em} 000$) ranges overlapping. Neutral buoyancy was chosen to eliminate one parameter, i.e. the influence of gravity, on the VIV behaviour, although, of course, the effect of added mass remains. The tether length was also chosen to be sufficiently long so that, to a good approximation, the sphere was constrained to move within a plane. Seven broad but relatively distinct sphere oscillation and wake states could be distinguished. For regime I, the wake is steady and axisymmetric, and it undergoes transition to a steady two-tailed wake in regime II at $\mathit{Re}= 210$. Those regimes are directly analogous to those of a fixed sphere. Once the sphere begins to vibrate at $\mathit{Re}\simeq 270$ in regime III, the wake behaviour is distinct from the fixed-sphere wake. Initially the vibration frequency of the sphere is half the shedding frequency in the wake, with the latter consistent with the fixed-sphere wake frequency. The sphere vibration is not purely periodic but modulated over several base periods. However, at slightly higher Reynolds numbers ($\mathit{Re}\simeq 280$), planar symmetry is broken, and the vibration shifts to the planar normal (or azimuthal) direction, and becomes completely azimuthal at the start of regime IV at $\mathit{Re}= 300$. In comparison, for a fixed sphere, planar symmetry is broken at a much higher Reynolds number of $\mathit{Re}\simeq 375$. Interestingly, planar symmetry returns to the wake for $\mathit{Re}\gt 330$, in regime V, for which the oscillations are again radial, and is maintained until $\mathit{Re}= 450$ or higher. At the same time, the characteristic vortex loops in the wake become symmetrical, i.e. two-sided. For $\mathit{Re}\gt 500$, in regime VI, the trajectory of the sphere becomes irregular, possibly chaotic. That state is maintained over the remaining Reynolds-number range simulated numerically ($\mathit{Re}\leq 800$). Experiments overlapping this Reynolds-number range confirm the amplitude radial oscillations in regime V and the chaotic wandering for regime VI. At still higher Reynolds numbers of $\mathit{Re}\gt 3000$, in regime VII, the trajectories evolve to quasi-circular orbits about the neutral point, with the orbital radius increasing as the Reynolds number is increased. At $\mathit{Re}= 12\hspace{0.167em} 000$, the orbital diameter reaches approximately one sphere diameter. Of interest, this transition sequence is distinct from that for a vertically tethered heavy sphere, which undergoes transition to quasi-circular orbits beyond $\mathit{Re}= 500$.
Convective shutdown in a porous medium at high Rayleigh number
Authors: Hewitt Duncan R. , Neufeld Jerome A. , Lister John R.
Published: March 2013

Convection in a closed domain driven by a dense buoyancy source along the upper boundary soon starts to wane owing to the increase of the average interior density. In this paper, theoretical and numerical models are developed of the subsequent long period of shutdown of convection in a two-dimensional porous medium at high Rayleigh number $\mathit{Ra}$. The aims of this paper are twofold. Firstly, the relationship between this slowly evolving ‘one-sided’ shutdown system and the statistically steady ‘two-sided’ Rayleigh–Bénard (RB) cell is investigated. Numerical measurements of the Nusselt number $\mathit{Nu}$ from an RB cell (Hewitt et al., Phys. Rev. Lett., vol. 108, 2012, 224503) are very well described by the simple parametrization $\mathit{Nu}= 2. 75+ 0. 0069\mathit{Ra}$. This parametrization is used in theoretical box models of the one-sided shutdown system and found to give excellent agreement with high-resolution numerical simulations of this system. The dynamical structure of shutdown can also be accurately predicted by measurements from an RB cell. Results are presented for a general power-law equation of state. Secondly, these ideas are extended to model more complex physical systems, which comprise two fluid layers with an equation of state such that the solution that forms at the (moving) interface is more dense than either layer. The two fluids are either immiscible or miscible. Theoretical box models compare well with numerical simulations in the case of a flat interface between the fluids. Experimental results from a Hele-Shaw cell and numerical simulations both show that interfacial deformation can dramatically enhance the convective flux. The applicability of these results to the convective dissolution of geologically sequestered ${\mathrm{CO} }_{2} $ in a saline aquifer is discussed.
Highly focused supersonic microjets: numerical simulations
Authors: Peters Ivo R. , Tagawa Yoshiyuki , Oudalov Nikolai , Sun Chao , Prosperetti Andrea , Lohse Detlef , van der Meer Devaraj
Published: March 2013

By focusing a laser pulse inside a capillary partially filled with liquid, a vapour bubble is created that emits a pressure wave. This pressure wave travels through the liquid and creates a fast, focused axisymmetric microjet when it is reflected at the meniscus. We numerically investigate the formation of this microjet using axisymmetric boundary integral simulations, where we model the pressure wave as a pressure pulse applied on the bubble. We find a good agreement between the simulations and experimental results in terms of the time evolution of the jet and on all parameters that can be compared directly. We present a simple analytical model that accurately predicts the velocity of the jet after the pressure pulse and its maximum velocity.
Nonlinear energy transfer between fluid sloshing and vessel motion
Authors: Turner M. R. , Bridges T. J.
Published: March 2013

This paper examines the dynamic coupling between a sloshing fluid and the motion of the vessel containing the fluid. A mechanism is identified that leads to an energy exchange between the vessel dynamics and fluid motion. It is based on a 1:1 resonance in the linearized equations, but nonlinearity is essential for the energy transfer. For definiteness, the theory is developed for Cooker’s pendulous sloshing experiment. The vessel has a rectangular cross-section, is partially filled with a fluid and is suspended by two cables. A nonlinear normal form is derived close to an internal 1:1 resonance, with the energy transfer manifested by a heteroclinic connection, which connects the purely symmetric sloshing modes to the purely antisymmetric sloshing modes. Parameter values where this pure energy transfer occurs are identified. In practice, this energy transfer can lead to sloshing-induced destabilization of fluid-carrying vessels.
Explicit filtering to obtain grid-spacing-independent and discretization-order-independent large-eddy simulation of two-phase volumetrically dilute flow with evaporation
Authors: Radhakrishnan Senthilkumaran , Bellan Josette
Published: March 2013

Predictions from conventional large-eddy simulation (LES) are known to be grid-spacing and spatial-discretization-order dependent. In a previous article (Radhakrishnan & Bellan,J. Fluid Mech., vol. 697, 2012a, pp. 399–435), we reformulated LES for compressible single-phase flow by explicitly filtering the nonlinear terms in the governing equations so as to render the solution grid-spacing and discretization-order independent. Having shown in Radhakrishnan & Bellan (2012a) that the reformulated LES, which we call EFLES, yields grid-spacing-independent and discretization-order-independent solutions for compressible single-phase flow, we explore here the potential of EFLES for evaporating two-phase flow where the small scales have an additional origin compared to single-phase flow. Thus, we created a database through direct numerical simulation (DNS) that when filtered serves as a template for comparisons with both conventional LES and EFLES. Both conventional LES and EFLES are conducted with two gas-phase SGS models; the drop-field SGS model is the same in all these simulations. For EFLES, we also compared simulations performed with the same SGS model for the gas phase but two different drop-field SGS models. Moreover, to elucidate the influence of explicit filtering versus gas-phase SGS modelling, EFLES with two drop-field SGS models but no gas-phase SGS models were conducted. The results from all these simulations were compared to those from DNS and from the filtered DNS (FDNS). Similar to the single-phase flow findings, the conventional LES method yields solutions which are both grid-spacing and spatial-discretization-order dependent. The EFLES solutions are found to be grid-spacing independent for sufficiently large filter-width to grid-spacing ratio, although for the highest discretization order this ratio is larger in the two-phase flow compared to the single-phase flow. For a sufficiently fine grid, the results are also discretization-order independent. The absence of a gas-phase SGS model leads to build-up of energy near the filter cut-off indicating that while explicit filtering removes energy above the filter width, it does not provide the correct dissipation at the scales smaller than this width. A wider viewpoint leads to the conclusion that although the minimum filter-width to grid-spacing ratio necessary to obtain the unique grid-independent solution might be different for various discretization-order schemes, the grid-independent solution thus obtained is also discretization-order independent.
Rogue wave occurrence and dynamics by direct simulations of nonlinear wave-field evolution
Authors: Xiao Wenting , Liu Yuming , Wu Guangyu , Yue Dick K. P.
Published: March 2013

We study the occurrence and dynamics of rogue waves in three-dimensional deep water using phase-resolved numerical simulations based on a high-order spectral (HOS) method. We obtain a large ensemble of nonlinear wave-field simulations ($M= 3$ in HOS method), initialized by spectral parameters over a broad range, from which nonlinear wave statistics and rogue wave occurrence are investigated. The HOS results are compared to those from the broad-band modified nonlinear Schrödinger (BMNLS) equations. Our results show that for (initially) narrow-band and narrow directional spreading wave fields, modulational instability develops, resulting in non-Gaussian statistics and a probability of rogue wave occurrence that is an order of magnitude higher than linear theory prediction. For longer times, the evolution becomes quasi-stationary with non-Gaussian statistics, a result not predicted by the BMNLS equations (without consideration of dissipation). When waves spread broadly in frequency and direction, the modulational instability effect is reduced, and the statistics and rogue wave probability are qualitatively similar to those from linear theory. To account for the effects of directional spreading on modulational instability, we propose a new modified Benjamin–Feir index for effectively predicting rogue wave occurrence in directional seas. For short-crested seas, the probability of rogue waves based on number frequency is imprecise and problematic. We introduce an area-based probability, which is well defined and convergent for all directional spreading. Based on a large catalogue of simulated rogue wave events, we analyse their geometry using proper orthogonal decomposition (POD). We find that rogue wave profiles containing a single wave can generally be described by a small number of POD modes.
The electrophoretic mobility of rod-like particles
Authors: Yariv Ehud , Schnitzer Ory
Published: March 2013

At finite Dukhin numbers, where Smoluchowski’s formula is inapplicable to thin-double-layer electrophoresis, the mobility of non-spherical particles is generally anisotropic. We consider bodies of revolution of otherwise arbitrary shape, where a uniformly applied electric field results in a rectilinear motion in the plane spanned by the field direction and the particle symmetry axis, as well as (for particles lacking fore–aft symmetry) rigid-body rotation about an axis perpendicular to that plane. Focusing upon slender particles, where the ratio $\epsilon $ of cross-sectional and longitudinal scales is asymptotically small, the translational and rotational mobilities are obtained as quadratures which depend upon the lengthwise distribution of the scaled cross-sectional width and the force densities associated with rigid-body motion. These mobility expressions approach finite limits as $\epsilon \rightarrow 0$, yielding closed-form expressions for specific particle geometries.
Wake and thrust of an angularly reciprocating plate
Authors: Lee Jeongsu , Park Yong-Jai , Jeong Useok , Cho Kyu-Jin , Kim Ho-Young
Published: March 2013

As one of the most important force production mechanisms of swimming and flying animals, the fluid dynamics of flapping has been intensively studied. However, these efforts have been mainly directed toward animals in forward motion or locomotive appendages undergoing linear translation. Here we seek to complement the existing knowledge of the flapping mechanism by studying angularly reciprocating flat plates without a free stream velocity, under a so-called ‘bollard pull’ condition. We visualize the flow field around the flat plate to find that two independent vortical structures are formed per half-cycle, resulting in the separation of two distinct vortex pairs at sharp edges rather than a single vortex loop which is typical of a starting–stopping vortex paradigm in flows with free streams. Based on our observations, we derive a scaling law to predict the thrust of the flapping plate; this is the first experimentally validated theoretical model for the thrust of angularly reciprocating plates without a prescribed background flow.
Axisymmetric travelling waves in annular sliding Couette flow at finite and asymptotically large Reynolds number
Authors: Deguchi K. , Walton A. G.
Published: March 2013

The relationship between numerical finite-amplitude equilibrium solutions of the full Navier–Stokes equations and nonlinear solutions arising from a high-Reynolds-number asymptotic analysis is discussed for a Tollmien–Schlichting wave-type two-dimensional vortical flow structure. The specific flow chosen for this purpose is that which arises from the mutual axial sliding of co-axial cylinders for which nonlinear axisymmetric travelling-wave solutions have been discovered recently by Deguchi & Nagata (J. Fluid Mech., vol. 678, 2011, pp. 156–178). We continue this solution branch to a Reynolds number $R= 1{0}^{8} $ and confirm that the behaviour of its so-called lower branch solutions, which typically produce a smaller modification to the laminar state than the other solution branches, quantitatively agrees with the axisymmetric asymptotic theory developed in this paper. We further find that this asymptotic structure breaks down when the disturbance wavelength is comparable with $R$. The new structure which replaces it is investigated and the governing equations are derived and solved. The flow visualization of the resultant solutions reveals that they possess a streamwise localized structure, with the trend agreeing qualitatively with full Navier–Stokes solutions for relatively long-wavelength disturbances.