bluuebunny/crossref_metadata_2025 huggingface dataset:
An optimal order finite element method for elliptic interface problems
Authors: Peichl Gunther H. , Touzani Rachid
Published: May 2009

A specific finite element method for problems involving interfaces is presented. The method allows for non fitted meshes and is well adapted for elliptic problems with jumps of coefficients along a closed curve. Error bounds for the presented method show optimal convergence. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preconditioned Krylov subspace method for the solution of least‐squares problems
Authors: Yin jun‐Feng , Hayami Ken , Bai Zhong‐Zhi
Published: May 2009

We consider preconditioned Krylov subspace iteration methods, e.g., CG, LSQR and GMRES, for the solution of large sparse least‐squares problems min ∥Ax – b ∥2, with A ∈ Rm×n, based on the Krylov subspaces Kk (BA, Br) and Kk (AB, r), respectively, where B ∈ Rn×m is the preconditioning matrix. More concretely, we propose and implement a class of incomplete QR factorization preconditioners based on the Givens rotations and analyze in detail the efficiency and robustness of the correspondingly preconditioned Krylov subspace iteration methods. A number of numerical experiments are used to further examine their numerical behaviour. It is shown that for both overdetermined and underdetermined least‐squares problems, the preconditioned GMRES methods are the best for large, sparse and ill‐conditioned matrices in terms of both CPU time and iteration step. Also, comparisons with the diagonal scaling and the RIF preconditioners are given to show the superiority of the newly‐proposed GMRES‐type methods. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability techniques in SIR epidemic models
Authors: Zaman Gul , Jung Il Hyo
Published: May 2009

In biological communities interaction among different species affect their stability. In this paper, we consider a nonlinear SIR model, which describes the dynamics of the interaction between susceptible and infected individuals in population. We establish stability techniques to find out the equilibria for the model and their numerical results are given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact fracture toughness and morphology of diatomite‐filled polypropylene composites
Authors: Liang Jizhao
Published: May 2009

Impact fracture strength is an important characterization for impact toughness of materials. A polypropylene (PP) filled with diatomite with different diameter (5, 7, and 13 μm) was fabricated by means a twin‐screw extruder. The impact fracture strength of these composites was measured at room temperature to identify the effects of diatomite content and diameter on impact fracture strength of filled polypropylene composites. The results showed that the influence of diatomite on the notched impact strength was significant. When the volume fraction of the diatomite (ϕf) was less than 10%, the notched impact strength (σI) increased quickly with an addition of ϕf, and then the variation of σI was slight. The notched impact strength of the composite with the diatomite diameter of 7 μm is the highest when ϕf was 10%. Furthermore, the impact fracture surface was observed by using a scanning electronic microscope (SEM) to study the toughening mechanisms. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Blue electroluminescence from 3,6‐silafluorene‐based copolymers
Authors: Mo Yue‐Qi , Deng Xian‐Yu , Jiang Xi , Cui Qiu‐Hong
Published: May 2009

Poly(3,6‐silafluorene) is a typical wide band‐gap conjugated polymer with ultraviolet light emission. The blue electroluminescence from the 3,6‐silafluorene‐based copolymers via intrachain energy transfer was reported in this study. The monomer containing vinylene, anthracene, and tri‐arylamine moieties incorporated into the poly(3,6‐silafluorene) backbone can form efficient deep‐blue emitting copolymers with EL efficiency of 1.1–1.9%. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3286–3295, 2009
Types, presentations and management of conjunctivitis
Authors: Tey Adrian
Published: May 2009

Conjunctivitis presents commonly in primary care and, though usually self‐limiting, early identification with optimal treatment is important to avoid complications. Here, the author describes the clinical features of the different types and their recommended management, followed by a prescription review and sources of further information. Copyright © 2009 Wiley Interface Ltd
Acute treatment and prophylaxis options for childhood migraine
Authors: Mewasingh Leena
Published: May 2009

Our series Prescribing in children gives practical advice for successful management of childhood problems in general practice. Here, the author describes the diagnosis, prevention and treatment of migraine in this age group. Copyright © 2009 Wiley Interface Ltd
Highly stable re‐dispersibility of nanocrystalline TiO2 observed during anatase–rutile phase transformation
Authors: Li Yanting , Sun Xiuguo , Li Huiwan , Wei Yu
Published: May 2009

TiO2 nanoparticles were prepared employing forced hydrolysis of titanium tetrachloride in an acid aqueous solution. We observed the highly stable dispersibility of TiO2 nanoparticles calcined at 600 °C and 700 °C in water. X‐ray diffraction (XRD) showed that the phase transformation from anatase (A) to rutile (R) occurred when the nanoparticles were calcined over 600 °C. Transmission electron microscope (TEM), Fourier‐transform infrared spectroscopy (FT‐IR) and Thermo‐gravimetric analysis (TGA) showed that the phase transformation led to the formation of the better spherical particlesis, which were in favour of water adsorption onto the surface of the TiO2. The Brunauer–Emmett–Teller (BET) data of particles calcined at different temperatures showed that the surface hydration forces impeded TiO2 particles aggregation and resulted in the high structural stability during A–R phases transformation. Zeta potentials of TiO2 nanoparticles calcined at different temperature showed the electrostatic forces were not crucial factors in the stable dispersibility. A model illustrated that the spherical particles of TiO2 allowed maintaining the high density of water on the surface of TiO2 nanoparticles. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of cosmetic ingredients causing extrusion‐coated and adhesive joint multilayer packaging delamination
Authors: Garrido‐López Álvaro , Santa‐Cruz Andrea , Moreno Elisabet , Cornago Judit , Cañas María Concepción , Tena María Teresa
Published: May 2009

In order to study the effect of several compounds on packaging stability, different cosmetic ingredients at two concentration levels were added to a NeoPCL® (Acofarma, Terrassa, Spain) water emulsion, and the preparations packed in sachets and stored at 40°C during 3 months. After that, the packaging was subjected to a T‐peel test and headspace solid‐phase microextraction gas chromatography mass spectrometry (HS‐SPME‐GC‐MS) analysis. The HS‐SPME‐GC‐MS analyses were performed using a 75 μm carboxen polydimethylsiloxane fibre to check for the presence of the studied analytes in the inner layers. The study revealed that the presence of a phenyl and a hydroxyl group in the compound structure lead to an important loss of adhesion between packaging layers joined by an adhesive. The interaction between the cosmetic ingredient and the adhesive was proposed as the main cause of the loss of adhesion. However, extrusion‐coating packaging was more susceptible to delamination, particularly with the volatile compounds. Copyright © 2009 John Wiley & Sons, Ltd.
Regression modeling of combined data from multiple sample surveys
Authors: Li Lei , Levy Paul S.
Published: May 2009

Combined data from multiple sample surveys are often used in population‐based epidemiologic studies. Combining data can be beneficial in that sampling errors are reduced and coverage biases are corrected. Also, it is often necessary in order to use information lacking in one survey but available in another. We propose an estimation equations method for generalized linear models from the combined data. The estimation procedures for logistic regression models and Poisson regression models are developed. An example of estimating the relative risk of death by smoking status is used as an illustration and a simulation study is performed to examine the performance of the method. Copyright © 2009 John Wiley & Sons, Ltd.
Telephoned BRCA1/2 Genetic Test Results: Prevalence, Practice, and Patient Satisfaction
Authors: Baumanis L. , Evans J. P. , Callanan N. , Susswein L. R.
Published: May 2009

While the traditional model of genetic evaluation for breast cancer risk recommended face‐to‐face disclosure of genetic testing results, BRCA1/2 testing results are increasingly provided by telephone. The few existing studies on telephone genetic counseling provide conflicting results about its desirability and efficacy. The current study aimed to (1) Estimate the prevalence among genetic counselors of providing BRCA1/2 genetic test results by phone (2) Assess patient satisfaction with results delivered by telephone versus in‐person. A survey was sent to members of the Familial Cancer Risk Counseling Special Interest Group via the NSGC listserve and was completed by 107 individuals. Additionally, 137 patients who had received BRCA genetic testing results either by phone or in‐person at UNC Chapel Hill Cancer Genetics Clinic were surveyed regarding satisfaction with the mode of their BRCA1/2 results delivery. The genetic counseling survey revealed that the majority of responding counselors (92.5%) had delivered BRCA1/2 genetic test results by telephone. Patients having received results either in person or by phone reported no difference in satisfaction. Most patients chose to receive results by phone and those given a choice of delivery mode reported significantly higher satisfaction than those who did not have a choice. Those who waited less time to receive results once they knew they were ready also reported higher satisfaction. This study found supportive results for the routine provision of BRCA1/2 genetic test results by telephone. Results suggest that test results should be delivered as swiftly as possible once available and that offering patients a choice of how to receive results is desirable. These are especially important issues as genetic testing becomes more commonplace in medicine.
One-Pot Reaction and Subsequent Annealing to Synthesis Hollow Spherical Magnetite and Maghemite Nanocages
Authors: Wu Wei , Xiao Xiangheng , Zhang Shaofeng , Li Hang , Zhou Xiaodong , Jiang Changzhong
Published: May 2009

Water-soluble hollow spherical magnetite (Fe3O4) nanocages (ca. 100 nm) with high saturation magnetization are prepared in a one-pot reaction by sol-gel method and subsequent annealing to synthesise the maghemite (γ-Fe2O3) nanocages with similar nanostructures. The nanocages have been investigated by powder X-ray diffraction (XRD), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), and superconducting quantum interference device (SQUID). The results indicated that glutamic acid played an important role in the formation of the cage-like nanostructures.
Effect of trans8, cis10+cis9, trans11 Conjugated Linoleic Acid Mixture on Lipid Metabolism in 3T3‐L1 Cells
Authors: Joseph Shama V. , Miller Jessica R. , McLeod Roger S. , Jacques Hélène
Published: May 2009

Evidence suggests that minor isomers of conjugated linoleic acid (CLA), such as trans8, cis10 CLA, can elicit unique biological effects of their own. In order to determine the effect of a mixture of t8, c10+c9, t11 CLA isomers on selected aspects of lipid metabolism, 3T3‐L1 preadipocytes were differentiated for 8 days in the presence of 100 μM linoleic acid (LA); t8, c10+c9, t11 CLA; t10, c12+c9, t11 CLA or purified c9, t11 CLA. Whereas supplementation with c9, t11 and t10, c12+c9, t11 CLA resulted in cellular triglyceride (TG) concentrations of 3.4 ± 0.26 and 1.3 ± 0.11 μg TG/μg protein, respectively (P < 0.05), TG accumulation following treatment with CLA mixture t8, c10+c9, t11 was significantly intermediate (2.5 ± 0.22 μg TG/μg protein, P < 0.05) between the two other CLA treatments. However, these effects were not attributable to an alteration of the Δ9 desaturation index. Adiponectin content of adipocytes treated with t8, c10+c9, t11 mixture was similar to the individual isomer c9, t11 CLA, and both the t8, c10+c9, t11 and c9, t11 CLA groups were greater (P < 0.05) than in the t10, c12+c9, t11 CLA group. Overall, these results suggest that t8, c10+c9, t11 CLA mixture affects TG accumulation in 3T3‐L1 cells differently from the c9, t11 and t10, c12 isomers. Furthermore, the reductions in TG accumulation occur without adversely affecting the adiponectin content of these cells.
Investigation of Emotional Responses to an Unexpected Price
Authors: Shirai Miyuri
Published: May 2009

This article investigates the emotions elicited from observing unexpectedly high or low prices, and how such emotions relate to purchase intentions. The experiment conducted to analyze these issues found that neutral emotions, surprised and amazed, were strongly elicited in both types of experiences. Among the various emotions elicited, discontented, depressed, and frustrated were felt strongly in the negative experience and pleased, excited, enthusiastic, contented, and thrilled were felt strongly in the positive experience. Moreover, most emotions were found to be the mediators of the effect of the price experience on purchase intentions. A structure for the unexpected price emotions was then investigated and found to be much simpler compared to that of consumption emotions presented by Richins [Richins, M.L., 1997. Measuring emotions in the consumption experience. Journal of Consumer Research 24 (9), 127–146].
“Sorry, We are Fully Booked!” – an Experimental Study of Preference Formation through Unavailable Services
Authors: Woratschek Herbert , Roth Stefan , Horbel Chris
Published: May 2009

As capacity is limited in many service industries, services are sometimes unavailable. Particularly, the most attractive offers may already be gone by the time consumers make their actual buying decision. As a consequence, they only find a less attractive choice set. Classical choice models suggest that irrelevant alternatives should not influence choice. However, past research showed that they still have an effect on consumer preference formation. In this paper, we examine three aspects of unavailable services and their influence on consumer decision-making: first, we argue that preference formation may depend upon the characteristics of the unavailable alternatives compared to those of the remaining services. Second, service providers can affect the decision context by revealing information about the unavailability at different stages of the decision process. Third, consumers’ perceptions about the causes for the unavailability could also affect the decision context. We investigate the impact of these factors on preference formation in two experimental studies. Results show that the perceived responsibility for the unavailability has the highest impact on the perceived attractiveness of the remaining alternatives.
Extended Field-of-View Sonography: Evaluation of the Superficial Lesions
Authors: Yerli Hasan , Eksioglu Secil Yucel
Published: May 2009

Objective

To evaluate the usefulness of extended-field-of-view 2-dimensional ultrasonography technique in superficial lesions.

Methods

During a 6-month period, 44 patients with superficial lesions on various parts of their bodies were evaluated with extended-field-of-view ultrasonography in addition to routine traditional 2-dimensional ultrasonography. If the diagnosis could not be made without the extended-field-of-view images, it was considered diagnostic. The radiologist decided if the extended-field-of-view ultrasonography helped spatial orientation, communicate findings, or compare the contralateral side in a single image, or if it was useful for follow-up evaluation.

Results

By using extended-field-of-view imaging including the surrounding anatomy, 22 musculoskeletal, 8 scrotal, 8 thyroid, 2 breast, and 4 abdominal wall lesions were documented successfully as a single image. Nevertheless, no new cases were diagnosed solely based on the extended-field-of-view images. Extended-field-of-view ultrasonography was considered helpful for spatial orientation in 25 cases (56.8%), for comparing the contralateral side in 16 cases (36.3%), and for communicating findings in 20 cases (45.4%). It was useful for follow-up evaluation in 13 cases (29.5%).

Conclusions

None of the extended-field-of-view images was diagnostic. However, they did provide valuable additional information and better documentation of the lesions.
Radiation Dose from Diagnostic Computed Tomography in Saskatchewan
Authors: Leswick David A. , Syed Nida S. , Dumaine Chance S. , Lim Hyun J. , Fladeland Derek A.
Published: May 2009

Objective

To calculate the effective dose from diagnostic computed tomography (CT) scans in Saskatchewan, Canada, and compare with other reported dose levels.

Methods

Data from CT scans were collected from 12 scanners in 7 cities across Saskatchewan. The patient age, scan type, and selected technique parameters including the dose length product and the volume computed tomography dose index were collected for a 2-week period. This information then was used to calculate effective doses patients are exposed to during CT examinations. Data from 2,061 clinically indicated CT examinations were collected, and of them 1,690 were eligible for analysis. Every examination during a 2-week period was recorded without selection.

Results

The average provincial estimated patient dose was as follows: head, 2.7 mSv (638 scans; standard deviation [SD], ±1.6); chest, 11.3 mSv (376 scans; SD, ±8.9); abdomen-pelvis, 15.5 mSv (578 scans; SD, ±10.0); abdomen, 11.7 mSv (80 scans; SD, ±11.48), and pelvis, 8.6 mSv (18 scans; SD, ±6.04). Significant variation in dose between the CT scanners was observed ( P = .049 for head, P = .001 for chest, and P = .034 for abdomen-pelvis).

Conclusions

Overall, the estimated dose from diagnostic CT examinations was similar to other previously published Canadian data from British Columbia. This dose varied slightly from some other published standards, including being higher than those found in a review conducted in the United Kingdom in 2003.
The Politics of Naming: Derozio in Two Formative Moments of Literary and Political Discourse, Calcutta, 1825–31
Authors: CHAUDHURI ROSINKA
Published: May 2009

Henry Derozio, India's first modern poet, used the pseudonym ‘An East Indian’ for several poems he published in his lifetime, and he may have used it again in a heated controversy that played itself out in the correspondence columns of the India Gazette, Calcutta's leading newspaper, from May 26 to June 5, 1825. The occasion was an editorial comment upon a community of office-goers in the city—called, at the time, ‘sircars’—who had set up a literary association. This editorial was widely perceived to be reactionary, and civil society responded vigorously in protest at the injustice. The sequence of editorials and letters published on this issue, which seem to have been written by Englishmen, East Indians and Indians alike, demonstrate a remarkable liberalism of spirit and a free-thinking attitude to ethnicity that was soon to disappear in the stiffening boundaries of a racially divided society. 1825 was also the year that Derozio began to publish prolifically in the poetry columns of newspapers and periodicals in the city; by the time he died, in 1831, he had published two books of poems in 1827 and 1828 and had created a revolution of sorts among the radicalised youth of the Hindu College, from which he had been dismissed for his role in their alienation from tradition. In 1831, a few months before his death, Derozio addressed a mammoth meeting called to commemorate the return of John Ricketts, the East Indian representative, from his mission to the English houses of Parliament for a redressal of the community's grievances. Using these two lost occasions—the public correspondence and the meeting—both concerned with the politics of naming, this paper will attempt to present the early radical interventions of the mixed-race community in initiating a discourse of civic rights and human dignity which led, ultimately, to organised attempts at constitutional change and political reform in India, whose estimation is underrated in present-day contexts.
Bullion for Trade, War, and Debt-Relief: British Movements of Silver to, around, and from Asia, 1760–1833
Authors: BOWEN H. V.
Published: May 2009

This paper provides the first detailed assessment of British exports of silver to Asia during the initial phase of imperial expansion in India. It demonstrates that, contrary to the views of some historians, exports of silver were at times very considerable, notably after 1785, when they were used to fund war and debt-relief in India, as well as for trade. Focus is on the East India Company, but attention is paid to private exports, to British transfers of silver around Asia, and the paper ends with an analysis of ‘reverse’ flows to Britain established after 1810.
Ethnonationalist Triads: Assessing the Influence of Kin Groups on Civil Wars
Authors: Cederman Lars-Erik , Girardin Luc , Gleditsch Kristian Skrede
Published: May 2009

Although the case-based literature suggests that kin groups are prominent in ethnonationalist conflicts, quantitative studies of civil war onset have both overaggregated and underaggregated the role of ethnicity, by looking at civil war at the country level instead of among specific groups and by treating individual countries as closed units, ignoring groups' transnational links. In this article the authors integrate transnational links into a dyadic perspective on conflict between marginalized ethnic groups and governments. They argue that transnational links can increase the risk of conflict as transnational kin support can facilitate insurgencies and are difficult for governments to target or deter. The empirical analysis, using new geocoded data on ethnic groups on a transnational basis, indicates that the risk of conflict is high when large, excluded ethnic groups have transnational kin in neighboring countries, and it provides strong support for the authors' propositions on the importance of transnational ties in ethnonationalist conflict.
Distribution and Redistribution: The Shadow of the Nineteenth Century
Authors: Iversen Torben , Soskice David
Published: May 2009

The authors present an alternative to power resource theory as an approach to the study of distribution and redistribution. While they agree that partisanship and union power are important, they argue that both are endogenous to more fundamental differences in the organization of capitalist democracies. specifically, center-left governments result from pr consensus political systems (as opposed to majoritarian systems), while strong unions have their origins in coordinated (as opposed to liberal) capitalism. These differences in political representation and in the organization of production developed jointly in the early twentieth century and explain the cross-national pattern of distribution and redistribution. The clusters have their origins in two distinct political economic conditions in the second half of the nineteenth century: one in which locally coordinated economies were coupled with strong guild traditions and heavy investment in cospecific assets and one in which market-based economies were coupled with liberal states and more mobile assets.
Institutional Development through Policy-Making: A Case Study of the Brazilian Central Bank
Authors: Taylor Matthew M.
Published: May 2009

A number of contemporary studies rightly emphasize the notion that policy outcomes result from institutional determinants. But as a growing literature on institutional development notes, these institutions are themselves impermanent. Sometimes, in crisis moments, institutions are replaced wholesale. More frequently, institutions evolve gradually over time. using the Brazilian Central Bank as a case study, this article illustrates that the policy-making process itself can be a central driver of gradual institutional development, with institutions evolving through the accumulation of policy choices made over many years and under different policymakers in response to contemporaneous events and unforeseeable economic and political challenges.
An acoustic analysis of prosody in high-functioning autism
Authors: DIEHL JOSHUA J. , WATSON DUANE , BENNETTO LOISA , MCDONOUGH JOYCE , GUNLOGSON CHRISTINE
Published: May 2009

This paper examined the fundamental frequency variation in the narratives of individuals with high-functioning autism (HFA) and typical controls matched on age, IQ, and verbal abilities. Study 1 found increased fundamental frequency variation in the speech of 21 children and adolescents with HFA when compared to 21 typical controls. Study 2 replicated the findings from Study 1 with a younger sample of 17 children with HFA and 17 typical controls. In addition, Study 1 found evidence that acoustic measurements of prosody were related to clinical judgments of autism-specific communication impairments, although this was not replicated in Study 2. Taken together, these studies provide evidence for differences in expressive prosody in individuals with HFA that can be measured objectively.
Talking about writing: What we can learn from conversations between parents and their young children
Authors: ROBINS SARAH , TREIMAN REBECCA
Published: May 2009

In six analyses using the Child Language Data Exchange System known as CHILDES, we explored whether and how parents and their 1.5- to 5-year-old children talk about writing. Parent speech might include information about the similarity between print and speech and about the difference between writing and drawing. Parents could convey similarity between print and speech by using the wordssay,name, andwordto refer to both spoken and written language. Parents could differentiate writing and drawing by making syntactic and semantic distinctions in their discussion of the two symbol systems. Our results indicate that parent speech includes these types of information. However, young children themselves sometimes confuse writing and drawing in their speech.
Bilingualism and aging: Reversal of the cognate advantage in older bilingual adults
Authors: SIYAMBALAPITIYA SAMANTHA , CHENERY HELEN J. , COPLAND DAVID A.
Published: May 2009

This study aimed to investigate cognate/noncognate processing distinctions in young adult bilinguals and examined whether the previously reported cognate facilitation effect would also be demonstrated in older adult bilinguals. Two groups of Italian–English bilingual participants performed lexical decisions in repetition priming experiments. Results for the younger bilinguals corresponded to previous findings, and indicated the expected reaction time advantage for cognates over noncognates. The older bilinguals, however, only demonstrated a cognate advantage in the within-language condition, and in fact, showed faster reaction times for noncognates when repetition was across languages. These findings are interpreted in the context of the revised hierarchical model and the bilingual interactive activation model and in light of findings regarding the effect of aging on language processing.
Some effective results for ×a×b
Authors: BOURGAIN JEAN , LINDENSTRAUSS ELON , MICHEL PHILIPPE , VENKATESH AKSHAY
Published: May 2009

We provide effective versions of theorems of Furstenberg and Rudolph–Johnson regarding closed subsets and probability measures of ℝ/ℤ invariant under the action of a non-lacunary multiplicative semigroup of integers. In particular, we give an explicit rate at which the sequence {anbkx}n,k becomes dense for a,b fixed multiplicatively independent integers and x∈ℝ/ℤ Diophantine generic.
Maximal entropy measures for piecewise affine surface homeomorphisms
Authors: BUZZI JÉRÔME
Published: May 2009

We study the dynamics of piecewise affine surface homeomorphisms from the point of view of their entropy. Under the assumption of positive topological entropy, we establish the existence of finitely many ergodic and invariant probability measures maximizing entropy and prove a multiplicative lower bound for the number of periodic points. This is intended as a step towards the understanding of surface diffeomorphisms. We proceed by building a jump transformation, using not first returns but carefully selected ‘good’ returns to dispense with Markov partitions. We control these good returns through some entropy and ergodic arguments.
Evaluation framework for the design of an engineering model
Authors: Ben Ahmed Walid , Mekhilef Mounib , Yannou Bernard , Bigand Michel
Published: May 2009

According to both cybernetics and general system theory, a subject develops and uses an adequate model of a system to widen his/her knowledge about the system. Models are then the interface between a subject and a real-world system to solve a problem and to construct knowledge. Hence, evaluating these models is crucial to ensure the quality of the constructed knowledge. We propose here an evaluation framework to assess complex models based on the intrinsic properties of these models as well as the properties of the derived knowledge. A series of 40 evaluation criteria are proposed under the four systemic axes: ontology, functioning, evolution, and teleology. Through a case study, we show how our evaluation model allows both presenting a given model and assessing it.
A Note on Universal and Canonically Coloured Sequences
Authors: DUDEK ANDRZEJ , FRANKL PETER , RÖDL VOJTĚCH
Published: May 2009

A sequence X = {xi}ni=1 over an alphabet containing t symbols is t-universal if every permutation of those symbols is contained as a subsequence. Kleitman and Kwiatkowski showed that the minimum length of a t-universal sequence is (1 − o(1))t2. In this note we address a related Ramsey-type problem. We say that an r-colouring χ of the sequence X is canonical if χ(xi) = χ(xj) whenever xi = xj. We prove that for any fixedt the length of the shortest sequence over an alphabet of size t, which has the property that every r-colouring of its entries contains a t-universal and canonically coloured subsequence, is at most $cr^{\lfloor\frac{t}{2}\rfloor}$. This is best possible up to a multiplicative constant c independent of r.
On 14-Cycle-Free Subgraphs of the Hypercube
Authors: FÜREDI ZOLTÁN , ÖZKAHYA LALE
Published: May 2009

It is shown that the size of a subgraph of Qn without a cycle of length 14 is of order o(|E(Qn)|).
Angststörungen
Authors: Petermann Franz , Lang Thomas
Published: May 2009

Angststörungen gehören zu den häufigsten psychischen Störungen des Erwachsenenalters. Als Behandlungsformen haben sich in den letzten Jahrzehnten vor allem Pharmako- und Verhaltenstherapie durchgesetzt. Der Grad der Evidenzbasierung dieser Methoden wird kritisch diskutiert und Perspektiven für die klinische Praxis erläutert.
The Time-Course of Masked Negative Priming
Authors: Frings Christian , Eder Andreas B.
Published: May 2009

Negative priming (NP) refers to the finding that reaction times and errors increase when a previously ignored prime distractor is presented as a target. In a variant of this task, the prime display is composed of only a single masked distractor that is followed by the simultaneous presentation of a target and a distractor in the probe display. In one experiment, we explore the time-course of masked NP using different variations of the prime-probe interval (short, medium, and long), and compare the results with time-course investigations of unmasked NP. We found clear evidence for a rapid-decay function of masked NP: With an increase in the prime-probe interval, masked NP decreased. This result is in line with the predictions of the temporal discrimination account and retrieval accounts of NP.
It Takes Just One Word to Quash a SNARC
Authors: Fischer Martin H. , Shaki Samuel , Cruise Alexander
Published: May 2009

Our directional reading habit seems to contribute to the widely reported association of small numbers with left space and larger numbers with right space (the spatial-numerical association of response codes, SNARC, effect). But how can this association be so flexible when reading habits are not? To address this question, we asked bilingual Russian-Hebrew readers to classify numbers by parity and alternated the number format from trial to trial between written words and Arabic digits. The number words were randomly printed in either Cyrillic or Hebrew script, thus inducing left-to-right or right-to-left reading, respectively. Classification performance indicated that the digits were spatially mapped when they followed a Russian word but not when they followed a Hebrew word. An auditory control experiment revealed left-to-right SNARC effects with different strengths in both languages. These results suggest that the SNARC effect reflects recent spatial experiences, cross-modal associations, and long-standing directional habits but not an attribute of the number concepts themselves.
Variations of meridional aerosol distribution and solar dimming
Authors: Kishcha P. , Starobinets B. , Kalashnikova O. , Long C. N. , Alpert P.
Published: May 2009

Meridional distribution of aerosol optical thickness (AOT) over the ocean was analyzed by using the 8‐year MISR and MODIS‐Terra data sets from March 2000 to February 2008, as well as the 5‐year MODIS‐Aqua data set from July 2002 to June 2007. The three satellite sensors show that there was a pronounced meridional aerosol asymmetry. It was found that there were strong seasonal variations in the meridional aerosol asymmetry: it was most pronounced in the April–July months. There was no noticeable asymmetry during the season from September to December. The Northern Hemisphere, where the main sources of natural and anthropogenic aerosols are located, contributed to the formation of noticeable aerosol asymmetry. During the season of pronounced hemispheric aerosol asymmetry, an increase in AOT was observed over the Northern Hemisphere, while a decrease in AOT was observed over the Southern Hemisphere. At midlatitudes in the Northern Hemisphere (30–60°N), the main contribution to seasonal variations of AOT over the ocean was made by Pacific Ocean aerosols. At low latitudes in the Northern Hemisphere (0–30°N), aerosols over the Atlantic Ocean contributed to seasonal variations of AOT more significantly than aerosols over the Pacific Ocean. During the 8‐year period under consideration, the brightening phenomenon, detected over the land, was not observed over the ocean at midlatitudes 30–60°N in cloudless conditions.
Simulation of dust aerosol radiative feedback using the Global Transport Model of Dust: 1. Dust cycle and validation
Authors: Yue Xu , Wang Huijun , Wang Zifa , Fan Ke
Published: May 2009

We have developed a Global Transport Model of Dust (GMOD) within a general circulation model, using comprehensive parameterizations of the emission and deposition processes from Wang et al. (2000). These parameterizations are modified to match the surface conditions and meteorological fields of the climate model. A 20‐year simulation from the dust model predicts an average dust emission of 1935 ± 51 Tg a−1 and a global dust burden of 27.8 ± 0.8 Tg for particles whose radii are smaller than 10 μm. Comparisons with observations show that the GMOD reproduces reasonably well dust concentrations (mean bias MB of −0.67 μg m−3, normalized mean bias NMB of −8.0%, correlation coefficient of 0.96 at 18 sites), logarithmic total deposition (−0.62 g m−2 a−1, −36.0%, 0.84 at 251 sites), and aerosol optical thickness (−0.04, −26.7%, 0.80 at 16 sites). The simulated dust particle size distribution is consistent with observations; both have a volume median radius in the range 1.0–4.0 μm. We examine the temporal variation of dust transport on different timescales. The simulated interannual variability is small, but the seasonal variation is quite large in the Sahara Desert and central Asia. We pay special attention to the diurnal variation of dust; both observations and simulations show that dust mobilization is more active during the local daytime than nighttime. On a global and annual mean basis, the simulated ratio of the daytime maximum uplift to the nighttime minimum is 75. Both the dust burden and dry deposition of dust show a similar diurnal cycle peaking in the late afternoon.
Sensitivity of climate to dynamically‐consistent zonal asymmetries in ozone
Authors: Gillett N. P. , Scinocca J. F. , Plummer D. A. , Reader M. C.
Published: May 2009

Previous investigations into the effect of zonal asymmetries in ozone on climate have compared simulations with prescribed 3‐D ozone, in which the ozone is not necessarily consistent with the model dynamics, to simulations with prescribed zonal mean ozone. We assess the impact of zonal asymmetries in ozone by comparing a control simulation of a coupled chemistry version of the Canadian Middle Atmosphere Model (CMAM) in which the ozone and model dynamics are consistent, with a simulation in which only the zonal mean of the ozone is passed to the radiative transfer scheme. These simulations reveal a robust stratospheric zonal‐mean temperature and geopotential height response to zonal asymmetries in ozone that is consistent with that identified in previous studies and of a magnitude comparable to observed trends. These results suggest that the inclusion of zonal asymmetries in ozone may be essential for the accurate simulation of future stratospheric temperature trends.
Cavities of weak magnetic field strength in the wake of FTEs: Results from global magnetospheric MHD simulations
Authors: Kuznetsova M. M. , Sibeck D. G. , Hesse M. , Wang Y. , Rastaetter L. , Toth G. , Ridley A.
Published: May 2009

We use the global magnetohydrodynamic (MHD) code BATS‐R‐US to model multipoint observations of Flux Transfer Event (FTE) signatures. Simulations with high spatial and temporal resolution predict that cavities of weak magnetic field strength protruding into the magnetosphere trail FTEs. These predictions are consistent with recently reported multi‐point Cluster observations of traveling magnetopause erosion regions (TMERs).
On the elusive hot oxygen corona of Venus
Authors: Lichtenegger H. I. M. , Gröller H. , Lammer H. , Kulikov Yu. N. , Shematovich V. I.
Published: May 2009

After more than two years in orbit still no Venus Express observations were published concerning the hot oxygen corona of Venus which could verify the corresponding controversial observations of Venera 11 and PVO, three decades ago. Based on recent energy and mass dependent collision cross sections, the energy distributions of hot atomic oxygen created via dissociative recombination of O2+ are calculated in the daytime thermosphere by means of a 3D Monte Carlo approach. The exosphere density is obtained from the corresponding energy density and angular distribution at 240 km altitude by using a test particle model which traces the ballistic trajectories of hot O atoms in the exosphere. Our study indicates that upon taking into account proper input parameters, the hot oxygen corona appears to be substantially less dense than suggested by previous simulations.
Control and benefits of CP4-57 prophage excision in Escherichia coli biofilms
Authors: Wang Xiaoxue , Kim Younghoon , Wood Thomas K
Published: May 2009

Earlier, we discovered that the global regulator, Hha, is related to cell death in biofilms and regulates cryptic prophage genes. Here, we show that Hha induces excision of prophages, CP4-57 and DLP12, by inducing excision genes and by reducing SsrA synthesis. SsrA is a tmRNA that is important for rescuing stalled ribosomes, contains an attachment site for CP4-57 and is shown here to be required for CP4-57 excision. These prophages impact biofilm development, as the deletion of 35 genes individually of prophages, CP4-57 and DLP12, increase biofilm formation up to 17-fold, and five genes decrease biofilm formation up to sixfold. In addition, CP4-57 excises during early biofilm development but not in planktonic cells, whereas DLP12 excision was detected at all the developmental stages for both biofilm and planktonic cells. CP4-57 excision leads to a chromosome region devoid of prophage and to the formation of a phage circle (which is lost). These results were corroborated by a whole-transcriptome analysis that showed that complete loss of CP4-57 activated the expression of the flg, flh and fli motility operons and repressed expression of key enzymes in the tricarboxylic acid cycle and of enzymes for lactate utilization. Prophage excision also results in the expression of cell lysis genes that reduce cell viability (for example, alpA, intA and intD). Hence, defective prophages are involved in host physiology through Hha and in biofilm formation by generating a diversified population with specialized functions in terms of motility and nutrient metabolism.
α-Helix targeting reduces amyloid-β peptide toxicity
Authors: Nerelius C. , Sandegren A. , Sargsyan H. , Raunak R. , Leijonmarck H. , Chatterjee U. , Fisahn A. , Imarisio S. , Lomas D. A. , Crowther D. C. , Strömberg R. , Johansson J.
Published: May 2009

The amyloid-β peptide (Aβ) can generate cytotoxic oligomers, and their accumulation is thought to underlie the neuropathologic changes found in Alzheimer's disease. Known inhibitors of Aβ polymerization bind to undefined structures and can work as nonspecific aggregators, and inhibitors that target conformations that also occur in larger Aβ assemblies may even increase oligomer-derived toxicity. Here we report on an alternative approach whereby ligands are designed to bind and stabilize the 13–26 region of Aβ in an α-helical conformation, inspired by the postulated Aβ native structure. This is achieved with 2 different classes of compounds that also reduce Aβ toxicity to cells in culture and to hippocampal slice preparations, and that do not show any nonspecific aggregatory properties. In addition, when these inhibitors are administered to
Drosophila melanogaster
expressing human Aβ
1–42
in the central nervous system, a prolonged lifespan, increased locomotor activity, and reduced neurodegeneration is observed. We conclude that stabilization of the central Aβ α-helix counteracts polymerization into toxic assemblies and provides a strategy for development of specific inhibitors of Aβ polymerization.
Identification of βArrestin2 as a corepressor of androgen receptor signaling in prostate cancer
Authors: Lakshmikanthan Vijayabaskar , Zou Lin , Kim Jae I. , Michal Allison , Nie Zhongzhen , Messias Nidia C. , Benovic Jeffrey L. , Daaka Yehia
Published: May 2009

Androgen receptor (AR) signaling regulates the development and homeostasis of male reproductive organs, including the prostate. Deregulation of AR and AR coregulators, expression, or activity is involved in the initiation of prostate cancer and contributes to the transition of the disease to hormone-refractory stage. The ubiquitous βArrestin proteins are now recognized as bona fide adapters and signal transducers with target effectors found in both the cytosol and nucleus. Here, we provide evidence that βArrestin2 forms a complex with AR and acts as an AR corepressor in androgen-dependent prostate cancer cells. Accordingly, the forced overexpression of βArrestin2 diminishes, and knockdown of βArrestin2 expression with RNAi increases the androgen-induced prostate-specific antigen (PSA) gene expression. βArrestin2 serves as an adapter, bringing into close proximity the Mdm2 E3 ligase and AR, thereby promoting AR ubiquitylation and degradation. Human prostate tissues evidence an inverse relationship between the expression of βArrestin2 and AR activity: glands that express high levels of βArrestin2 exhibit low expression of PSA, and those glands that express low levels of βArrestin2 evidence elevated PSA levels. We conclude that βArrestin2 acts as a corepressor of AR by serving as a scaffold for Mdm2 leading to the AR ubiquitylation and degradation.
The contribution of relexification, grammaticalisation, and reanalysis to creole genesis and development
Authors: Lefebvre Claire
Published: May 2009

The theory of creole genesis developed in Lefebvre (1998 and related work) is formulated within the framework of the processes otherwise known to play a role in language genesis and language change in general, that is, relexification, grammaticalisation and reanalysis. This paper evaluates the respective contribution of these processes to creole genesis and development. The following issues are taken up. Can functional categories undergo relexification? Is the process at work in creole genesis best characterised as relexification or as transfer? Can there be cases of partial relexification? Are grammaticalisation and reanalysis distinct processes? Is keeping them separate useful in studying creole genesis and development? How are these three processes articulated with respect to each other in creole genesis and development?
SWI/SNF Deficiency Results in Aberrant Chromatin Organization, Mitotic Failure, and Diminished Proliferative Capacity
Authors: Bourgo Ryan J. , Siddiqui Hasan , Fox Sejal , Solomon David , Sansam Courtney G. , Yaniv Moshe , Muchardt Christian , Metzger Daniel , Chambon Pierre , Roberts Charles W.M. , Knudsen Erik S.
Published: May 2009

Switch (SWI)/sucrose nonfermentable (SNF) is an evolutionarily conserved complex with ATPase function, capable of regulating nucleosome position to alter transcriptional programs within the cell. It is known that the SWI/SNF complex is responsible for regulation of many genes involved in cell cycle control and proliferation, and it has recently been implicated in cancer development. The ATPase action of SWI/SNF is conferred through either the brahma-related gene 1 (Brg1) or brahma (Brm) subunit of the complex, and it is of central importance to the modification of nucleosome position. In this study, the role of the Brg1 and Brm subunits were examined as they relate to chromatin structure and organization. Deletion of the Brg1 ATPase results in dissolution of pericentromeric heterochromatin domains and a redistribution of histone modifications associated with these structures. This effect was highly specific to Brg1 and is not reproduced by the loss of Brm or SNF5/BAF47/INI1. Brg1 deficiency is associated with the appearance of micronuclei and aberrant mitoses that are a by-product of dissociated chromatin structure. Thus, Brg1 plays a critical role in maintaining chromatin structural integrity.
Hsp90 Regulates the Function of Argonaute 2 and Its Recruitment to Stress Granules and P-Bodies
Authors: Pare Justin M. , Tahbaz Nasser , López-Orozco Joaquín , LaPointe Paul , Lasko Paul , Hobman Tom C.
Published: May 2009

Argonaute proteins are effectors of RNA interference that function in the context of cytoplasmic ribonucleoprotein complexes to regulate gene expression. Processing bodies (PBs) and stress granules (SGs) are the two main types of ribonucleoprotein complexes with which Argonautes are associated. Targeting of Argonautes to these structures seems to be regulated by different factors. In the present study, we show that heat-shock protein (Hsp) 90 activity is required for efficient targeting of hAgo2 to PBs and SGs. Furthermore, pharmacological inhibition of Hsp90 was associated with reduced microRNA- and short interfering RNA-dependent gene silencing. Neither Dicer nor its cofactor TAR RNA binding protein (TRBP) associates with PBs or SGs, but interestingly, protein activator of the double-stranded RNA-activated protein kinase (PACT), another Dicer cofactor, is recruited to SGs. Formation of PBs and recruitment of hAgo2 to SGs were not dependent upon PACT (or TRBP) expression. Together, our data suggest that Hsp90 is a critical modulator of Argonaute function. Moreover, we propose that Ago2 and PACT form a complex that functions at the level of SGs.