bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase equilibria of molecular fluids via hybrid Monte Carlo Wang–Landau simulations: Applications to benzene and n-alkanes
Authors: Desgranges Caroline , Delhommelle Jerome
Published: June 2009

In recent years, powerful and accurate methods, based on a Wang–Landau sampling, have been developed to determine phase equilibria. However, while these methods have been extensively applied to study the phase behavior of model fluids, they have yet to be applied to molecular systems. In this work, we show how, by combining hybrid Monte Carlo simulations in the isothermal-isobaric ensemble with the Wang–Landau sampling method, we determine the vapor-liquid equilibria of various molecular fluids. More specifically, we present results obtained on rigid molecules, such as benzene, as well as on flexible chains of n-alkanes. The reliability of the method introduced in this work is assessed by demonstrating that our results are in excellent agreement with the results obtained in previous work on simple fluids, using either transition matrix or conventional Monte Carlo simulations with a Wang–Landau sampling, and on molecular fluids, using histogram reweighting or Gibbs ensemble Monte Carlo simulations.
Adsorption and diffusion of Au atoms on the (001) surface of Ti, Zr, Hf, V, Nb, Ta, and Mo carbides
Authors: Florez Elizabeth , Viñes Francesc , Rodriguez Jose A. , Illas Francesc
Published: June 2009

The adsorption of atomic Au on the (001) surface of TiC, ZrC, HfC, VC, NbC, TaC, and δ-MoC and the mechanism of diffusion of this adatom through the surface have been studied in terms of a periodic density functional theory based approach. In all the cases, the Au adsorption energies are in the range of 1.90–2.35 eV. The moderately large adsorption energies allow the Au diffusion before desorption could take place. For TiC(001), ZrC(001), and HfC(001), atomic Au is adsorbed directly on top of C atoms and diffusion takes place along the diagonal of the squares formed by M-C-M-C atoms with the transition state located above the hollow sites. For the rest of transition metal carbides the situation is less simple with the appearance of more than one stable adsorption site, as for NbC and TaC, of a small energy barrier for diffusion around the most stable adsorption site and of a more complex diffusion pathway. The small energy barrier for diffusion around the most stable site will result in a highly mobile Au species which could be observed in scanning tunnel microscope experiments. After depositing Au on metal-carbide surfaces, there is a noticeable charge transfer from the substrate to the adsorbed Au atom. The electronic perturbations on Au increase when going from TiC to ZrC or TaC. Our results indicate that metal carbides should be better supports for the chemical activation of Au than metal oxides.
The influence of periodic islands in the flow on a scalar tracer in the presence of a steady source
Authors: Turner M. R. , Thuburn J. , Gilbert A. D.
Published: June 2009

In this paper we examine the influence of periodic islands within a time periodic chaotic flow on the evolution of a scalar tracer. The passive scalar tracer is injected into the flow field by means of a steady source term. We examine the distribution of the tracer once a periodic state is reached, in which the rate of injected scalar balances advection and diffusion with the molecular diffusion κ. We study the two-dimensional velocity field u(x,y,t)=2 cos2(ωt)(0,sin x)+2 sin2(ωt)(sin y,0). As ω is reduced from an O(1) value the flow alternates through a sequence of states which are either globally chaotic, or contain islands embedded in a chaotic sea. The evolution of the scalar is examined numerically using a semi-Lagrangian advection scheme. By time-averaging diagnostics measured from the scalar field we find that the time-averaged lengths of the scalar contours in the chaotic region grow like κ−1/2 for small κ, for all values of ω, while the behavior of the time-averaged maximum scalar value, Cmax¯, for small κ depends strongly on ω. In the presence of islands Cmax¯∼κ−α for some α between 0 and 1 and with κ small, and we demonstrate that there is a correlation between α and the area of the periodic islands, at least for large ω. The limit of small ω is studied by considering a flow field that switches from u=(0,2 sin x) to u=(2 sin y,0) at periodic intervals. The small κ limit for this flow is examined using the method of matched asymptotic expansions. Finally the role of islands in the flow is investigated by considering the time-averaged effective diffusion of the scalar field. This diagnostic can distinguish between regions where the scalar is well mixed and regions where the scalar builds up.
Melting and crystallization of nanocrystalline silicon microwires through rapid self-heating
Authors: Bakan G. , Cywar A. , Silva H. , Gokirmak A.
Published: June 2009

Nanocrystalline silicon microwires are self-heated through single, large amplitude, and microsecond voltage pulses. Scanning electron micrographs show very smooth wire surfaces after the voltage pulse compared to as-fabricated nanocrystalline texture. Voltage-pulse induced self-heating leads to significant conductance improvement, suggesting crystallization of the wires. The minimum resistivity during the pulse is extracted from wires of different dimensions as 75.0±4.6 μΩ cm, matching previously reported values for liquid silicon. Hence, nanocrystalline silicon microwires melt through self-heating during the voltage pulse and resolidify upon termination of the pulse, resulting in very smooth and less-resistive crystalline structures.
Observation of whispering gallery modes in nonpolar m-plane GaN microdisks
Authors: Tamboli Adele C. , Schmidt Mathew C. , Hirai Asako , DenBaars Steven P. , Hu Evelyn L.
Published: June 2009

We have fabricated nonpolar GaN/InGaN microdisks using band-gap selective photoelectrochemical etching. These microdisks have a smoother optical cavity than our previous c-plane microdisks, and they support whispering gallery modes with quality factors as high as 2000 after a focused ion beam treatment to the quantum wells. Because of the lack of a Stokes shift in the quantum wells of these m-plane disks, absorption losses play a much more significant role than in our earlier c-plane microdisks, and the light which couples into the modes is emission from the InGaN post rather than the quantum wells within the cavity.
Preface to Special Topic: Papers from the 2009 Conference on Advances in Microfluidics and Nanofluidics, The Hong Kong University of Science & Technology, Hong Kong, 2009
Authors: Yeo Leslie Y.
Published: June 2009

The inaugural conference on Advances in Microfluidics and Nanofluidics was held at the Hong Kong University of Science and Technology on 5–7 January 2009 and brought together leading researchers from across a wide variety of disciplines from North America, Europe, Asia, and Oceania. This Special Topic section forms the second of the two issues dedicated to original contributions covering both fundamental physicochemical aspects of microfluidics and nanofluidics as well as their applications to the miniaturization of chemical and biological systems that were presented at the conference.
Tokamak profile prediction using direct gyrokinetic and neoclassical simulation
Authors: Candy J. , Holland C. , Waltz R. E. , Fahey M. R. , Belli E.
Published: June 2009

Tokamak transport modeling scenarios, including ITER [ITER Physics Basis Editors, Nucl. Fusion 39, 2137 (1999)] performance predictions, are based exclusively on reduced models for core thermal and particle transport. The reason for this is simple: computational cost. A typical modeling scenario may require the evaluation of thousands of individual transport fluxes (local transport models calculate the energy and particle fluxes across a specified flux surface given fixed profiles). Despite continuous advances in direct gyrokinetic simulation, the cost of an individual simulation remains so high that direct gyrokinetic transport calculations have been avoided. By developing a steady-state iteration scheme suitable for direct gyrokinetic and neoclassical simulations, we can now compute steady-state temperature profiles for DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] plasmas given known plasma sources. The new code, TGYRO, encapsulates the GYRO [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] code, for turbulent transport, and the NEO [E. A. Belli and J. Candy, Plasma Phys. Controlled Fusion 50, 095010 (2008)] code, for kinetic neoclassical transport. Results for DIII-D L-mode discharge 128913 are given, with computational and experimental results consistent in the region 0≤r/a≤0.8.
Molecular noise of capping protein binding induces macroscopic instability in filopodial dynamics
Authors: Zhuravlev Pavel I. , Papoian Garegin A.
Published: June 2009

Capping proteins are among the most important regulatory proteins involved in controlling complicated stochastic dynamics of filopodia, which are dynamic finger-like protrusions used by eukaryotic motile cells to probe their environment and help guide cell motility. They attach to the barbed end of a filament and prevent polymerization, leading to effective filament retraction due to retrograde flow. When we simulated filopodial growth in the presence of capping proteins, qualitatively different dynamics emerged, compared with actin-only system. We discovered that molecular noise due to capping protein binding and unbinding leads to macroscopic filopodial length fluctuations, compared with minuscule fluctuations in the actin-only system. Thus, our work shows that molecular noise of signaling proteins may induce micrometer-scale growth–retraction cycles in filopodia. When capped, some filaments eventually retract all the way down to the filopodial base and disappear. This process endows filopodium with a finite lifetime. Additionally, the filopodia transiently grow several times longer than in actin-only system, since less actin transport is required because of bundle thinning. We have also developed an accurate mean-field model that provides qualitative explanations of our numerical simulation results. Our results are broadly consistent with experiments, in terms of predicting filopodial growth retraction cycles and the average filopodial lifetimes.
Metal-independent decomposition of hydroperoxides by halogenated quinones: Detection and identification of a quinone ketoxy radical
Authors: Zhu Ben-Zhan , Shan Guo-Qiang , Huang Chun-Hua , Kalyanaraman Balaraman , Mao Li , Du Yu-Guo
Published: June 2009

We have shown recently that halogenated quinones could enhance the decomposition of hydroperoxides and formation of alkoxyl/hydroxyl radicals through a metal-independent mechanism. However, neither the proposed quinone enoxy radical intermediate, nor the major reaction products were unambiguously identified. In the present study, one of the major reaction products between 2,5-dichloro-1,4-benzoquinone (DCBQ) and
t
-butylhydroperoxide (
t
-BuOOH) was isolated and purified by semipreparative HPLC, and identified as 2-hydroxy-3-
t
-butoxy-5-chloro-1,4-benzoquinone [CBQ(OH)-O-
t
-Bu], which is the rearranged isomer of the postulated quinone-peroxide reaction intermediate. The formation of CBQ(OH)-O-
t
-Bu was found to be inhibited by the spin trapping agent 5,5-dimethyl-1-pyrroline
N
-oxide (DMPO), and concurrently, a new DMPO adduct with 1-chlorine isotope peak clusters at
m
/
z
268 was observed. Further electron spin resonance (ESR) spin-trapping,
1
H-NMR and HPLC/Fourier transform ion cyclotron resonance (FTICR) mass spectrometric studies with oxygen-17-labeled and unlabeled hydrogen peroxide strongly suggest that the radical trapped by DMPO is a carbon-centered quinone ketoxy radical, which is the spin isomer of the proposed oxygen-centered quinone enoxy radical. Analogous results were observed when DCBQ was substituted by other halogenated quinones. This study represents the first detection and identification of an unusual carbon-centered quinone ketoxy radical, which provides direct experimental evidence to further support and expand our previously proposed mechanism for metal-independent decomposition of hydroperoxides by halogenated quinones.
The macroscopic delamination of thin films from elastic substrates
Authors: Vella Dominic , Bico José , Boudaoud Arezki , Roman Benoit , Reis Pedro M.
Published: June 2009

The wrinkling and delamination of stiff thin films adhered to a polymer substrate have important applications in “flexible electronics.” The resulting periodic structures, when used for circuitry, have remarkable mechanical properties because stretching or twisting of the substrate is mostly accommodated through bending of the film, which minimizes fatigue or fracture. To date, applications in this context have used substrate patterning to create an anisotropic substrate-film adhesion energy, thereby producing a controlled array of delamination “blisters.” However, even in the absence of such patterning, blisters appear spontaneously, with a characteristic size. Here, we perform well-controlled experiments at macroscopic scales to study what sets the dimensions of these blisters in terms of the material properties and explain our results by using a combination of scaling and analytical methods. Besides pointing to a method for determining the interfacial toughness, our analysis suggests a number of design guidelines for the thin films used in flexible electronic applications. Crucially, we show that, to avoid the possibility that delamination may cause fatigue damage, the thin film thickness must be greater than a critical value, which we determine.
Online Academic Integrity
Authors: Mastin David F. , Peszka Jennifer , Lilly Deborah R.
Published: June 2009

Psychology students completed a task with reinforcement for successful performance. We tested academic integrity under randomly assigned conditions of check mark acknowledgment of an honor pledge, typed honor pledge, or no pledge. Across all conditions, 14.1% of students inflated their self-reported performance (i.e., cheated). We found no significant differences in the likelihood of cheating under differing honor pledge conditions. Students were more likely to cheat in late semester (20.2% and 16.0%) compared to the early semester condition (9.6%). Our research is important in understanding the frequency and timing of online academic dishonesty.
Introducing Students to Psychological Research: General Psychology as a Laboratory Course
Authors: Thieman Thomas J. , Clary E. Gil , Olson Andrea M. , Dauner Rachel C. , Ring Erin E.
Published: June 2009

For 6 years, we have offered an integrated weekly laboratory focusing on research methods as part of our general psychology course. Through self-report measures and controlled comparisons, we found that laboratory projects significantly increase students' knowledge and comfort level with scientific approaches and concepts, sustain interest in psychology, and increase critical thinking about psychological research. Implementing a laboratory component in the introductory course increases students' scientific literacy, reinforces psychology's claim to scientific status, encourages active learning, promotes quantitative reasoning, and benefits multiple constituencies.
E-Mail from Professor Enhances Student Motivation and Attitudes
Authors: Legg Angela M. , Wilson Janie H.
Published: June 2009

Traditionally, professors use the first day of class to build rapport. However, current technology allows professors to contact students prior to the first day of class. This study assessed how the receipt of a welcoming e-mail from a female professor 1 week before the first day of class affected student motivation and attitudes toward the instructor and course. Introductory psychology students evaluated the professor at 3 time points throughout the semester. Several outcomes indicated that an e-mail sent before the semester began was sufficient to enhance motivation and attitudes toward the instructor and course on the first day (and, for female students, throughout the semester) and also impacted student retention. Thus, a welcoming e-mail might offer an easy way for professors to communicate immediacy to their students before they even enter the classroom.
Ethnicity and low achievement in English schools
Authors: Kingdon Geeta , Cassen Robert
Published: June 2009

Tens of thousands of young people leave school with no or very few qualifications in England. This paper asks: what is the ethnic dimension of the low achievement problem? We focus on six aspects, using the National Pupil Database: whether the relation between ethnicity and incidence of low achievement is symmetrical with the relation between ethnicity and achievement; whether economic disadvantage is an equally large risk factor for low achievement among pupils of all ethnicities; whether the relationship of ethnicity with low achievement varies by peer group; whether the relationship between gender and chances of low achievement differs by ethnic group; whether the relation between ethnicity and low achievement changes with age; and lastly, whether there is sorting by ethnicity into schools of better or worse quality. We find that: (1) the relationship between low achievement and achievement is not symmetrical and, therefore, that it is valuable to measure low achievement directly rather than as the negative of achievement; (2) economic disadvantage has a stronger effect on White students than those of ethnic minorities; (3) the relationship between ethnicity and low achievement does vary with age; (4) ethnic peer‐group effects are not significant; (5) the gender gap in the probability of low achievement is significantly larger for most ethnic groups compared with the White group, at least by one measure of low achievement; and (6) attending poorer‐quality schools is part of the explanation of differential ethnic minority performance. We offer explanations for our findings and for the presence and/or persistence of inter‐ethnic differences in the chances of low achievement.
Secondary school vice‐principals: Commitment, challenge, efficacy and synchrony
Authors: Yu‐Kwong Paula Kwan , Walker Allan
Published: June 2009

The study sought to investigate Hong Kong secondary school vice‐principals’ job facets leading to overall job satisfaction, and to differentiate the satisfaction of vice‐principals of different career orientations and gender groups. The findings indicated that there are four main facets of satisfaction, in rank order of influence on overall satisfaction, ‘professional commitment’, ‘level of personal challenge’, ‘sense of efficacy’ and ‘sense of synchrony’. The study also found that vice‐principals who aspired to the principalship exhibited a higher degree of professional commitment, a stronger sense of efficacy, and experienced lower levels of stress associated with personal challenge than vice‐principals who did not aspire to a principalship.
Resilience and loss in work identities: A narrative analysis of some retired teachers’ work‐life histories
Authors: Kirk John , Wall Christine
Published: June 2009

The article examines the importance of ‘emotional labour’ in the constitution of the ‘teacherly‐self’. Deriving from a research project on work and social identity, the article explores the ways teachers have negotiated the radical changes in the profession in recent years, and uses the notion of ‘teacher resilience’ to explore the ways teachers have reacted to the effects of neo‐liberal reforms to education; reforms that have powerfully impacted on the more child‐centred ways of working in the classroom and school environment. Using narrative analysis of the work‐life histories of these retired teachers, recorded using oral history methodology, the authors examine structures of feeling that turn on notions of emotional labour and commitment, resilience and loss in relation to the occupational identity of teachers.
Correction for patient sway in radiographic biplanar imaging for three-dimensional reconstruction of the spine: in vitro study of a new method
Authors: Legaye J. , Saunier P. , Dumas R. , Vallee C.
Published: June 2009

Background: Three-dimensional (3D) reconstructions of the spine in the upright position are classically obtained using two-dimensional, non-simultaneous radiographic imaging. However, a subject's sway between exposures induces inaccuracy in the 3D reconstructions.

Purpose: To evaluate the impact of patient sway between successive radiographic exposures, and to test if 3D reconstruction accuracy can be improved by a corrective method with simultaneous Moiré–X-ray imaging.

Material and Methods: Using a calibrated deformable phantom perceptible by both techniques (Moiré and X-ray), the 3D positional and rotational vertebral data from 3D reconstructions with and without the corrective procedure were compared to the corresponding data of computed tomography (CT) scans, considered as a reference. All were expressed in the global axis system, as defined by the Scoliosis Research Society.

Results: When a sagittal sway of 10° occurred between successive biplanar X-rays, the accuracy of the 3D reconstruction without correction was 8.8 mm for the anteroposterior vertebral locations and 6.4° for the sagittal orientations. When the corrective method was applied, the accuracy was improved to 1.3 mm and 1.5°, respectively.

Conclusion: 3D accuracy improved significantly by using the corrective method, whatever the subject's sway. This technique is reliable for clinical appraisal of the spine, if the subject's sway does not exceed 10°. For greater sway, improvement persists, but a risk of lack of accuracy exists.
Computerised CBT self‐help for depression in Higher Education: Reflections on a pilot
Authors: Mitchell Nicky
Published: June 2009

Aims: This study comprised the second phase of a small‐scale exploration of the viability of a computerised CBT intervention for depression within the context of a Higher Education counselling service. Method: The program ‘Beating the Blues’™ (BtB) was offered to students experiencing depression, with measurement of uptake, attrition, satisfaction and effectiveness of the program. Results: Outcomes were calculated alone and in combination with those found in Phase One (previously presented in this journal), to enable a whole study report. In Phase Two, 15 students commenced BtB. The low completion rate in the intended academic year of the study led to extension over a further term. Seven participants completed the programme in Phase Two, a rate of 46.7%; 27 students used the programme over the entire study, with 63% completion. In both phases depression scores fell significantly following completion of the programme; anxiety scores fell significantly for Phase Two completers. User feedback was mixed. Clinical implications and conclusions: Many students have a comparatively short wait for a psychological service which may reduce interest in a computerised self‐help intervention and may help explain the low uptake. It is suggested that whilst CCBT is acceptable and effective for some depressed students, the number of sufficiently interested students, together with reported satisfaction from the intervention, was too small to warrant current inclusion of BtB within our service, particularly given its cost implications. Suggestions for further CCBT‐related investigations within this setting are made.
The university and social responsiveness in the curriculum: a new form of scholarship?
Authors: Favish Judith , McMillan Janice
Published: June 2009

Challenges facing the higher education sector globally include questions over what counts as knowledge and what are valid forms of both its reproduction and production. This paper addresses the question of how what counts as valid knowledge is challenged and how it changes over time.
It does this via an analysis of examples of social responsiveness profiled as 'portraits of practice' in the annual social responsiveness reports produced at the University of Cape Town, South Africa, a traditionally strong research university. In this paper, we discuss and analyse key themes
emerging from this work and argue that social responsiveness not only serves to enhance the core functions of teaching and research but can act to change them.
Threshold practices: becoming a student through academic literacies
Authors: Gourlay Lesley
Published: June 2009

Student transitions into the university are often conceived of via an apprentice-type model, or as entrance into a 'community of practice'. This paper disputes the applicability of these models to the indeterminate and opaque nature of student experiences of academic writing, and proposes
that emotional destabilization and struggles around identity are a normal part of both transitions and writing. With reference to student text/visual journals and in-depth interviews, it argues for extending the notion of 'threshold concepts', proposing academic literacies as 'threshold practices'
which can lead to a reinforced sense of identity as a student. It concludes with implications for practice.
Seeing the future: Natural image sequences produce “anticipatory” neuronal activity and bias perceptual report
Authors: Perrett David I. , Xiao Dengke , Barraclough Nick E. , Keysers Christian , Oram Mike W.
Published: June 2009

This paper relates human perception to the functioning of cells in the temporal cortex that are engaged in high-level pattern processing. We review historical developments concerning (a) the functional organization of cells processing faces and (b) the selectivity for faces in cell responses. We then focus on (c) the comparison of perception and cell responses to images of faces presented in sequences of unrelated images. Specifically the paper concerns the cell function and perception in circumstances where meaningful patterns occur momentarily in the context of a naturally or unnaturally changing visual environment. Experience of visual sequences allows anticipation, yet one sensory stimulus also “masks” perception and neural processing of subsequent stimuli. To understand this paradox we compared cell responses in monkey temporal cortex to body images presented individually, in pairs and in action sequences. Responses to one image suppressed responses to similar images for ∼500 ms. This suppression led to responses peaking 100 ms earlier to image sequences than to isolated images (e.g., during head rotation, face-selective activity peaks before the face confronts the observer). Thus forward masking has unrecognized benefits for perception because it can transform neuronal activity to make it predictive during natural change.
Random noun generation in younger and older adults
Authors: Heuer Herbert , Janczyk Markus , Kunde Wilfried
Published: June 2009

We examined age-related changes of executive functions by means of random noun generation. Consistent with previous observations on random letter generation, older participants produced more prepotent responses than younger ones. In the case of random noun generation, prepotent responses are nouns of the same category as the preceding noun. In contrast to previous observations, older participants exhibited stronger repetition avoidance and a stronger tendency toward local evenness—that is, toward equal frequencies of the alternative responses even in short subsequences. These data suggest that at higher adult age inhibition of prepotent responses is impaired. In addition, strategic attentional processes of response selection are strengthened, in particular the application of a heuristic for randomness. In this sense response selection is more controlled in older than in younger adults.
The role of working memory in auditory selective attention
Authors: Dalton Polly , Santangelo Valerio , Spence Charles
Published: June 2009

A growing body of research now demonstrates that working memory plays an important role in controlling the extent to which irrelevant visual distractors are processed during visual selective attention tasks (e.g., Lavie, Hirst, De Fockert, & Viding, 2004). Recently, it has been shown that the successful selection of tactile information also depends on the availability of working memory (Dalton, Lavie, & Spence, 2009). Here, we investigate whether working memory plays a role in auditory selective attention. Participants focused their attention on short continuous bursts of white noise (targets) while attempting to ignore pulsed bursts of noise (distractors). Distractor interference in this auditory task, as measured in terms of the difference in performance between congruent and incongruent distractor trials, increased significantly under high (vs. low) load in a concurrent working-memory task. These results provide the first evidence demonstrating a causal role for working memory in reducing interference by irrelevant auditory distractors.
On the size of Kakeya sets in finite fields
Authors: Dvir Zeev
Published: June 2009

A Kakeya set is a subset of

F

n

\mathbb {F}^n

, where

F

\mathbb {F}

is a finite field of

q
q

elements, that contains a line in every direction. In this paper we show that the size of every Kakeya set is at least

C

n

⋅

q

n

C_{n} \cdot q^{n}

, where

C

n

C_{n}

depends only on

n
n

. This answers a question of Wolff.
Quantum cohomology of the Hilbert scheme of points on 𝒜_{𝓃}-resolutions
Authors: Maulik Davesh , Oblomkov Alexei
Published: June 2009

We determine the two-point invariants of the equivariant quantum cohomology of the Hilbert scheme of points of surface resolutions associated to type

A

n

A_{n}

singularities. The operators encoding these invariants are expressed in terms of the action of the the affine Lie algebra

g
l

^

(
n
+
1
)

\widehat {\mathfrak {gl}}(n+1)

on its basic representation. Assuming a certain nondegeneracy conjecture, these operators determine the full structure of the quantum cohomology ring. A relationship is proven between the quantum cohomology and Gromov-Witten/Donaldson-Thomas theories of

A

n

×

P

1

A_{n}\times \mathbf {P}^1

. We close with a discussion of the monodromy properties of the associated quantum differential equation and a generalization to singularities of types

D
D

and

E
E

.
Rigorous derivation of the Gross-Pitaevskii equation with a large interaction potential
Authors: Erdős László , Schlein Benjamin , Yau Horng-Tzer
Published: June 2009

Consider a system ofNNbosons in three dimensions interacting via a repulsive short range pair potentialN2V(N(xi−xj))N^2V(N(x_i-x_j)), wherex=(x1,…,xN)\mathbf {x}=(x_1, \ldots , x_N)denotes the positions of the particles. LetHNH_Ndenote the Hamiltonian of the system and letψN,t\psi _{N,t}be the solution to the Schrödinger equation. Suppose that the initial dataψN,0\psi _{N,0}satisfies the energy condition\[⟨ψN,0,HNψN,0⟩≤CN\langle \psi _{N,0}, H_N \psi _{N,0} \rangle \leq C N\]and that the one-particle density matrix converges to a projection asN→∞N \to \infty. Then, we prove that thekk-particle density matrices ofψN,t\psi _{N,t}factorize in the limitN→∞N \to \infty. Moreover, the one particle orbital wave function solves the time-dependent Gross-Pitaevskii equation, a cubic nonlinear Schrödinger equation with the coupling constant proportional to the scattering length of the potentialVV. In a recent paper, we proved the same statement under the condition that the interaction potentialVVis sufficiently small. In the present work we develop a new approach that requires no restriction on the size of the potential.
SLE and the free field: Partition functions and couplings
Authors: Dubédat Julien
Published: June 2009

Schramm-Loewner Evolutions (SLE) are random curves in planar simply connected domains; the massless (Euclidean) free field in such a domain is a random distribution. Both have conformal invariance properties in law. In the present article, some relations between the two objects are studied. We establish identities of partition functions between different versions of SLE and the free field with appropriate boundary conditions; this involves

ζ
\zeta

-regularization and the Polyakov-Alvarez conformal anomaly formula. We proceed with a construction of couplings of SLE with the free field, showing that, in a precise sense, chordal SLE is the solution of a stochastic “differential” equation driven by the free field. Existence, uniqueness in law, and pathwise uniqueness for these SDEs are proved for general

κ
>
0

\kappa >0

. This identifies SLE curves as local observables of the free field.
Modelling seasonal and annual variation in size at functional maturity in the European lobster (Homarus gammarus) from self-sampling data
Authors: Laurans Martial , Fifas Spyros , Demaneche Sébastien , Brérette Stéphane , Debec Olivier
Published: June 2009

Laurans, M., Fifas, S., Demaneche, S., Brérette, S., and Debec, O. 2009. Modelling seasonal and annual variation in size at functional maturity in the European lobster (Homarus gammarus) from self-sampling data. – ICES Journal of Marine Science, 66: 1892–1898. Fishers from Le Croisic (France) measure all the lobsters (Homarus gammarus) they capture, indicating their sex and whether the females are ovigerous or non-ovigerous. Between 2003 and 2006 and mainly between April and September, 16 884 lobsters were measured in this manner. These self-sampled data were used to study catchability and functional maturity of lobsters. The sex ratio was 50%, and catchability did not change if a female was ovigerous or non-ovigerous. With the help of a logistic function, a relationship was established between body size and the proportion of ovigerous females. For the study area, 100% of the females were mature upon reaching a carapace length (CL) of 115 mm, and the proportion of ovigerous females reached 70% each year. The L50 value evolved over a CL of 103–106 mm. From the size when 100% of the females matured (115 mm), there was a larger proportion of ovigerous females than in other studies carried out in more northern European areas.
Reproductive ecology of the invasive whelk Rapana venosa Valenciennes, 1846, in the southeastern Black Sea (Gastropoda: Muricidae)
Authors: Sağlam Hacer , Düzgüneş Ertuğ , Öğüt Hamdi
Published: June 2009

Sağlam, H., Düzgüneş, E., and Öğüt, H. 2009. Reproductive ecology of the invasive whelk Rapana venosa Valenciennes, 1846, in the southeastern Black Sea (Gastropoda: Muricidae). – ICES Journal of Marine Science, 66: 1865–1867. The reproductive ecology of the invasive whelk Rapana venosa Valenciennes, 1846 (Gastropoda: Muricidae) was examined in Surmene, southeastern Black Sea, Turkey, using monthly samples of individuals collected by dredging from November 1999 to October 2000. The observed sex ratio (F:M) was 1:1.6; mean shell length at sexual maturity was 40 mm. Changes in the ovary and testis indices indicated that spawning mainly occurred between June and early August in the southeastern Black Sea.
RNA Interference Targeted to the Conserved Dimerization Initiation Site (DIS) of HIV-1 Restricts Virus Escape Mutation
Authors: Sugiyama Ryuichi , Habu Yuichiro , Ohnari Aki , Miyano-Kurosaki Naoko , Takaku Hiroshi
Published: June 2009

Short hairpin RNAs (shRNA) targeting viral or cellular genes can effectively inhibit human immunodeficiency virus type 1 (HIV-1) replication. This inhibition, however, may induce mutations in the targeted gene, leading to rapid escape from the shRNA-induced inhibition. We generated a lymphoid cell line that stably expressed a 19-bp shRNA targeting a well-conserved dimerization initiation site (DIS) of HIV-1, which strongly inhibited viral replication, thereby delaying virus escape. Furthermore, treatment of HIV-1 infection with DIS- and vif-shRNA combination therapy resulted in superior anti-viral responses compared to vif-shRNA monotherapy. Continuous challenge with HIV-1, however, generated virus mutants that could overcome the RNA interference restriction. Such anti-genes may be promising tools for HIV-1 gene therapy for HIV/acquired immunodeficiency syndrome.
Latitude, elevation and the tempo of molecular evolution in mammals
Authors: Gillman Len N. , Keeling D. Jeanette , Ross Howard A. , Wright Shane D.
Published: June 2009

Faster rates of microevolution have been recorded for plants and marine foraminifera occupying warmer low latitude environments relative to those occurring at higher latitudes. By contrast, because this rate heterogeneity has been attributed to a relationship between thermal habit and mutagenesis via a body temperature linkage, it has been assumed that microevolution in mammals should not also vary systematically with environmental temperature. However, this assumption has not previously been empirically examined. In this study, we tested for a thermally mediated influence on the tempo of microevolution among mammals using a comprehensive global dataset that included 260 mammal species, from 10 orders and 29 families. In contrast to theoretical predictions, we found that substitution rates in the cytochromebgene have been substantially faster for species living in warmer latitudes and elevations relative to sister species living in cooler habitats. These results could not be attributed to factors otherwise thought to influence rates of microevolution, such as body mass differentials or genetic drift. Instead, the results indicate that the tempo of microevolution among mammals is either responding directly to the thermal environment or indirectly via an ecological mechanism such as the ‘Red Queen’ effect.
Effects of ocean acidification on the early life history of a tropical marine fish
Authors: Munday Philip L. , Donelson Jennifer M. , Dixson Danielle L. , Endo Geoff G. K.
Published: June 2009

Little is known about how fishes and other non-calcifying marine organisms will respond to the increased levels of dissolved CO
2
and reduced sea water pH that are predicted to occur over the coming century. We reared eggs and larvae of the orange clownfish,
Amphiprion percula
, in sea water simulating a range of ocean acidification scenarios for the next 50–100 years (current day, 550, 750 and 1030 ppm atmospheric CO
2
). CO
2
acidification had no detectable effect on embryonic duration, egg survival and size at hatching. In contrast, CO
2
acidification tended to increase the growth rate of larvae. By the time of settlement (11 days post-hatching), larvae from some parental pairs were 15 to 18 per cent longer and 47 to 52 per cent heavier in acidified water compared with controls. Larvae from other parents were unaffected by CO
2
acidification. Elevated CO
2
and reduced pH had no effect on the maximum swimming speed of settlement-stage larvae. There was, however, a weak positive relationship between length and swimming speed. Large size is usually considered to be advantageous for larvae and newly settled juveniles. Consequently, these results suggest that levels of ocean acidification likely to be experienced in the near future might not, in isolation, significantly disadvantage the growth and performance of larvae from benthic-spawning marine fishes.
A critical role of Sonic Hedgehog signaling in maintaining the tumorigenicity of neuroblastoma cells
Authors: Mao Ling , Xia Yuan‐Peng , Zhou Yu‐Nan , Dai Ruo‐Lian , Yang Xue , Duan Shu‐Jie , Qiao Xian , Mei Yuan‐Wu , Hu Bo , Cui Hongjuan
Published: June 2009

Accumulated evidence suggests a major role for the activation of the Sonic Hedgehog (SHH) signaling pathway in the development of neural crest stem cells that give rise to the sympathetic nervous system. We therefore investigated the involvement of SHH signaling in the pathogenesis of neuroblastoma, a common childhood malignant tumor of the sympathetic nervous system. Human neuroblastoma cell lines and a majority of primary neuroblastoma specimens showed high‐level expression of the pathway targets and components, indicating persistent activation of the SHH pathway. All of the neuroblastoma cell lines we examined expressed significant levels of SHH ligand, suggesting an autocrine, ligand‐dependent activation of the SHH pathway in neuroblastoma cells. Inhibition of SHH signaling by cyclopamine induced apoptosis and blocked proliferation in all major types of neuroblastoma cells, and abrogated the tumorigenicity of neuroblastoma cells. Moreover, the knockdown of GLI2 in neuroblastoma BE (2)‐C and SK‐N‐DZ cell lines resulted in the inhibition of colony formation. Our study has revealed a molecular mechanism for the persistent activation of the SHH pathway which promotes the development of neuroblastoma, and suggests a new approach for the treatment of this childhood malignant tumor. (Cancer Sci 2009; 100: 1848–1855)
Intraperitoneal administration of paclitaxel solubilized with poly(2‐methacryloxyethyl phosphorylcholine‐co n‐butyl methacrylate) for peritoneal dissemination of gastric cancer
Authors: Soma Daisuke , Kitayama Joji , Konno Tomohiro , Ishihara Kazuhiko , Yamada Jun , Kamei Takao , Ishigami Hironori , Kaisaki Shoichi , Nagawa Hirokazu
Published: June 2009

Intraperitoneal (i.p.) administration of paclitaxel (PTX) is a hopeful therapeutic strategy for peritoneal malignancy. Intravenously (i.v.) injected nanoparticle anticancer drugs are known to be retained in the blood stream for a long time and favorably extravasated from vessels into the interstitium of tumor tissue. In this study, we evaluated the effect of i.p. injection of PTX (PTX‐30W), which was prepared by solubulization with water‐soluble amphiphilic polymer composed of PMB‐30W, a co‐polymer of 2‐methacryloxyethyl phosphorylcholineand n‐butyl methacrylate, for peritoneal dissemination of gastric cancer. In a peritoneal metastasis model with transfer of MKN45P in nude mice, the effct of i.p. administration of PTX‐30W was compared with conventional PTX dissolved in Cremophor EL (PTX‐Cre). The drug accumulation in peritoneal nodules was evaluated with intratumor PTX concentration and fluorescence microscopic observation. PTX‐30W reduced the number of metastatic nodules and tumor volume significantly more than did conventional PTX dissolved in Cremophor EL (PTX‐Cre), and prolonged the survival time (P < 0.05). PTX concentration in disseminated tumors measured by HPLC was higher in the PTX‐30W than in the PTX‐Cre group up to 24 h after i.p. injection. Oregon green–conjugated PTX‐30W, i.p. administered, preferentially accumulated in relatively hypovascular areas in the peripheral part of disseminated nodules, which was significantly greater than the accumulation of PTX‐Cre. I.p. administration of PTX‐30W may be a promising strategy for peritoneal dissemination, due to its superior characteristics to accumulate in peritoneal lesions. (Cancer Sci 2009; 100: 1979–1985)
Relationships between rust resistance genes at the M locus in flax
Authors: LAWRENCE GREGORY J. , ANDERSON PETER A. , DODDS PETER N. , ELLIS JEFFREY G.
Published: June 2009

Genes at the M locus in flax (Linum usitatissimum) that confer resistance to flax rust (Melampsora lini) occur in complex haplotypes containing up to 15 related genes or gene fragments. We have cloned two additional functional resistance genes at this locus, M1 and M3, by transposon tagging and candidate gene approaches, and investigated the genetic relationships between four genes (M, M1, M3 and M4) by recombination analysis. M1 and M3, like M, are members of the nucleotide binding site, leucine‐rich repeat (NBS‐LRR) family. Comparisons of the predicted M1 and M3 amino acid sequences with M and L6 reveal that: (i) M1 contains four additional LRRs, probably as a result of an unequal crossover event between duplicated regions; (ii) M1 shares large segments of exact identity with M and M3, indicative of intragenic recombination events; and (iii) a large number of amino acid differences are scattered throughout the M, M1 and M3 proteins. Recombination analysis (here and in previous studies) has revealed that M readily recombines with M1, M3 and M4, whereas these three genes fail to recombine despite large family sizes (>5800) in two test‐cross families, suggesting that they may occupy allelic positions in the gene cluster. Several restriction fragment length polymorphism markers within or near the M locus were mapped with respect to seven crossover events between M and M1. The results of this and previous studies provide evidence of structural differences between: (i) homoeologous loci in the different genomes of flax; (ii) different haplotypes at the M locus; (iii) different resistance genes in the M group; and (iv) the flanking regions downstream of M locus resistance genes.
Effect of the urotensin‐II receptor antagonist palosuran on secretion of and sensitivity to insulin in patients with Type 2 diabetes mellitus
Authors: Sidharta Patricia N. , Rave Klaus , Heinemann Lutz , Chiossi Eleonora , Krähenbühl Stephan , Dingemanse Jasper
Published: June 2009

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Urotensin‐II (U‐II) is one of the most potent vasoconstrictors identified thus far.

• Although differences in both U‐II blood levels and U‐II receptor (UT‐receptor) expression have been observed in patients with cardiovascular and cardiorenal disease, the precise function in humans has not been elucidated.

• U‐II and its receptor have been reported to be involved in glucose metabolism and insulin resistance, which can lead to the development of Type 2 diabetes mellitus.

• In rat models of diabetes, palosuran, a selective, potent antagonist of the human UT‐receptor, improved several disease markers.

WHAT THIS STUDY ADDS

• In this study in diabetic patients, the effects of palosuran on insulin secretion and sensitivity were investigated using a hyperglycaemic glucose clamp and a meal tolerance test and daily glucose levels were also studied.

• Although no obvious beneficial effect of palosuran in this patient population was observed, the study contributes to providing more insight inro the human U‐II/UT‐receptor system.

AIMS

To investigate the effects of palosuran, a nonpeptidic, potent and selective antagonist of the urotensin‐II receptor, on insulin and glucose regulation in 20 diet‐treated patients with Type 2 diabetes mellitus in a double‐blind, placebo‐controlled, randomized, crossover, proof‐of‐concept study.

METHODS

After 4 weeks' oral treatment with 125 mg palosuran or placebo b.i.d., effects on insulin secretion and sensitivity and blood glucose levels were assessed by means of a hyperglycaemic glucose clamp, meal tolerance test, homeostasis model assessment‐insulin resistance score, and daily self‐monitoring of blood glucose. Plasma concentrations of palosuran were determined for 12 h on the last day of intake.

RESULTS

Palosuran did not affect second‐phase insulin response (primary end‐point) during the hyperglycaemic glucose clamp in comparison with placebo [paired difference of −1.8 µU ml−1, 95% confidence interval (CI) −7.8, 4.2]. Likewise, no effects of palosuran were detected on the first‐phase insulin response, or on insulin secretion and blood glucose levels during the meal tolerance test or on homeostasis model assessment‐insulin resistance score. No clinically significant effects on daily blood glucose profiles were observed during the study. Geometric mean Cmax and AUCτ (95% CI) and median tmax (range) in this patient population were 180 ng ml−1 (125, 260), 581 ng·h ml−1 (422, 800) and 3.0 h (0.67, 4.3), respectively.

CONCLUSIONS

The results of this study indicate that antagonism of the urotensin‐II system does not influence insulin secretion or sensitivity or daily blood glucose levels in diet‐treated patients with Type 2 diabetes.