bluuebunny/crossref_metadata_2025 huggingface dataset:
GRAVITATIONAL FIELD OF STATIC THIN PLANAR WALLS IN WEAK-FIELD APPROXIMATION
Authors: CAMPANELLI L. , CEA P. , FOGLI G. L. , TEDESCO L.
Published: November 2003

We investigate gravitational properties of thin planar wall solutions of the Einstein's equations in the weak field approximation. We find the general metric solutions and discuss the behavior of a particle placed initially at rest to one side of the plane. Moreover we study the case of non-reflection-symmetric solutions.
THE DIRICHLET OBSTRUCTION IN AdS/CFT
Authors: ÁLVAREZ ENRIQUE , CONDE JORGE , HERNÁNDEZ LORENZO
Published: November 2003

The obstruction for a perturbative reconstruction of the five-dimensional bulk metric starting from the four-dimensional metric at the boundary, that is, the Dirichlet problem, is computed in dimensions 6≤d≤10 and some comments are made on its general structure and, in particular, on its relationship with the conformal anomaly, which we compute in dimension d=8.
PLANETARY MIGRATION IN EVOLVING PLANETESIMAL DISKS
Authors: SAFFET YEŞİLYURT İ. , NİHAL ERCAN E. , DEL POPOLO A.
Published: November 2003

In the current paper, we further improved the model for the migration of planets introduced and extended to time-dependent planetesimal accretion disks by Del Popolo. In the current study, the assumption of Del Popolo, that the surface density in planetesimals is proportional to that of gas, is relaxed. In order to obtain the evolution of planetesimal density, we use a method developed by Stepinski and Valageas which is able to simultaneously follow the evolution of gas and solid particles for up to 107 years. Then, the disk model is coupled to migration model introduced by Del Popolo in order to obtain the migration rate of the planet in the planetesimal. We find that the properties of solids known to exist in protoplanetary systems, together with reasonable density profiles for the disk, lead to a characteristic radius in the range 0.03–0.2 AU for the final semi-major axis of the giant planet.Hence our model can explain the properties of discovered extrasolar giant planets.
ELECTRONIC STRUCTURE OF THE FINITE-SIZED SINGLE-WALLED CARBON NANOTUBES
Authors: UDOMVECH ANURAK , KERDCHAROEN TEERAKIAT , PARASUK VUDHICHAI , TANTIRUNGROTECHAI YUTHANA , OSOTCHAN TANAKORN
Published: November 2003

The effects of tubule length and terminal capping on the geometrical and electronic properties of finite-sized zig-zag (9, 0) single-walled carbon nanotubes (SWNT), which length varying from 2 up to 12 unit cells (~50 Å), were investigated using molecular mechanics, semi-empirical methods (AM1 and EHMO) and density functional theory (B3LYP). AM1 method indicates how the nanotube ends are capped affects strongly the tubule geometric parameters. Although these effects seem to decrease exponentially as the tube gets longer, the converging values for C–C bond length in the open- and closed-end structures are slightly different. It was learned that combination of low-level methods like AM1 and EHMO (which tend to overestimate and underestimate the HOMO–LUMO energy gap, respectively) together with high-level method such as DFT is efficient to estimate band gap for finite-sized nanostructures. The HOMO–LUMO energy gaps obtained from semi-empirical and DFT methods decrease as the tubule length increases. Terminal capping also affects strongly the electronic structure of finite-sized nanotube. Thus, closing the terminal ends by fullerene hemisphere broadens the energy gap of the hydrogen-saturated open-end nanotube. Although the open-end SWNT has much lower AM1 HOMO–LUMO energy gap than the closed-end SWNT, these orbitals unfortunately are localized near the capping hydrogen, thereby do not provide conducting channels for electrons. By comparing only the delocalized frontier orbitals, both structures yield closer energy gap. Analysis of the energy gap based on EHMO, AM1 and DFT results suggests that both open- and closed-end finite-sized SWNT are semiconductor, in agreement with recent scanning tunneling experiment. It was found that the slight accumulated negative charges are likely to locate at the nanotube's fullerene tips.
Acute Ischemic Cerebrovascular Syndrome
Authors: Kidwell Chelsea S. , Warach Steven
Published: November 2003

Background—

Existing diagnostic classification systems for cerebrovascular disease are based primarily on clinical impression of temporal features, clinical syndrome, inferred localization, or ischemic mechanism. Diagnostic certainty of the ischemic pathology based on supportive or refuting laboratory or radiological evidence has been of secondary importance.

Summary of Comment—

Acute ischemic cerebrovascular syndrome
(AICS) describes a spectrum of clinical presentations that share a similar underlying pathophysiology: cerebral ischemia. Diagnostic criteria for AICS incorporate prior classification systems and currently available information provided by neuroimaging and laboratory data to define 4 categories ranging from “definite AICS” to “not AICS,” which define the degree of diagnostic certainty.

Conclusions—

Clinical trials testing new treatments for acute ischemic stroke or secondary stroke prevention should limit enrollment to patients with “definite” AICS whenever feasible.
Angiotensin-Converting Enzyme Inhibitor Use Is Associated With Reduced Plasma Concentration of C-Reactive Protein in Patients With First-Ever Ischemic Stroke
Authors: Di Napoli Mario , Papa Francesca
Published: November 2003

Background and Purpose—

High levels of C-reactive protein (CRP) are associated with an increased risk of future cardiovascular events in ischemic stroke. It has been hypothesized that the benefit of angiotensin-converting enzyme (ACE) inhibitors in patients at high vascular risk may also result from their anti-inflammatory action. Data evaluating this hypothesis are limited in ischemic stroke.

Methods—

We conducted a prospective observational study in 507 patients with first-ever ischemic stroke to analyze the effect of ACE inhibitor treatment at the time of stroke onset on CRP levels within the first 24 hours and the relationship to outcome. Risk estimates were calculated according to Cox regression analysis controlled for blood pressure (BP) levels, clinical and neuroradiological confounding variables, and log-normalized CRP levels at entry.

Results—

ACE inhibitor treatment was associated with lower (2.6-fold;
P
<0.0001) median CRP levels and with a reduced 2-year cardiovascular risk (hazard ratio, 0.39; 95% CI, 0.29 to 0.53;
P
<0.0001) compared with a different BP-lowering regimen. The relationship between ACE inhibitor status and log-normalized CRP levels remained significant (
P
<0.0001) after we controlled for important confounding variables and concomitant treatments. The reduced risk was also evident in multivariable analysis when ACE inhibitor treatment was controlled for BP, associated risk factors, neuroradiological findings, and concomitant treatments (hazard ratio, 0.43; 95% CI, 0.30 to 0.62;
P
<0.0001). This risk reduction was greatly attenuated and not more significant when log-normalized CRP levels were included (hazard ratio, 0.67; 95% CI, 0.43 to 1.04;
P
=0.0721) in the model.

Conclusions—

Concomitant treatment with ACE inhibitor at the time of an acute stroke is associated with lower inflammatory response and better long-term outcomes, apparently apart from the effects on BP.
Visual Interactive Simulation for Distance Education
Authors: de Lara Juan , Alfonseca Manuel
Published: November 2003

The authors discuss the necessity of multiple flexible output forms in an educational Web simulation environment. Ideally, such an environment should allow the creation of visual, interactive simulations and their integration in the pages of the Web document being constructed. As a suitable candidate for this, the authors propose their system to generate documents for the Web that consists of three layers: continuous simulation language OOCSMP and its associated language layers SODA-1L and SODA- 2L. OOCSMP and SODA are compiled into Java applets and HTML/VRML pages by a compiler called C-OOL. Different output forms can be combined to solve and show the results of a simulation problem. The authors propose a procedure to guide the construction of educational courses on technical or scientific subjects with their tools. This procedure is used to enhance an existing educational Web course with a new page showing the simulation of a robot arm Unimation PUMA260.
Transnational Advertising and International Relations: US Press Discourses on the Benetton ‘We on Death Row’ Campaign
Authors: Kraidy Marwan M. , Goeddertz Tamara
Published: November 2003

This article analyzes Benetton’s 2000 ‘We on Death Row’ advertising campaign as a site of cultural production where ideological differences on capital punishment between the United States and Europe are played out. We examine the massmediated public discourse framing the campaign in the US prestige press. More specifically, we conduct a textual analysis of news stories and editorials about the campaign in the Washington Post, New York Times, Los Angeles Times, and Chicago Tribune. Our analysis uncovered three themes, denigration, commodification and othering, that the press uses to discredit the campaign. The discussion focuses on how national hegemonic media frames ‘domesticate’ foreign social ideals.
The Belly Dancer Strategy: Israeli Educational Television and its Alternatives
Authors: Oren Tasha G.
Published: November 2003

By the 1960s, the question of instituting a television service in Israel had become the subject of a public controversy and a political debate. Hailed as a great educational tool by some and a dangerous ‘culture bomb’ by others, television facilitated a process of cultural self-definition as Israelis struggled to set the wouldbe service apart and shield it from the cultural influences of American television on the one hand and Arab television on the other. All the while, official imaginings of television as an educational, national utility clashed with public speculations about popular entertainment and commercial content. This article traces the cultural pressures, political anxieties, public speculations and industry marketing campaigns that accompanied the initial planning stages and establishment of an Israeli educational television service. In particular, it illustrates how conceptions of television galvanized a national debate over cultural taste, national identity, political ideology and Israeli differentiation within the Arab world.
Comparing Traditional Focus Groups with a Group Support Systems (GSS) Approach for Use in SME Research
Authors: Newby Rick , Soutar Geoff , Watson John
Published: November 2003

This study examined the use of Group Support Systems (GSS) technology as a tool for soliciting perceptions, or ideas, from a target audience. We compared this approach to a more traditional focus group methodology, and concluded that GSS technology has a number of advantages. First, the relative anonymity of responses encouraged participation from the more timid group members, ensuring vocal individuals did not dominate. Second, the GSS technology made the findings available to group members immediately, so that clarification, correction and some quantitative analysis of responses could take place during the session. Third, the GSS approach allowed ideas to be separated from the person, ensuring that any subsequent discussion was depersonalized. Fourth, the results were available immediately after the session. Finally, the GSS technology was more cost effective because the additional cost of using this approach was more than offset by the savings from not having to transcribe participants’ responses.
Safe Navigation for Indoor Mobile Robots. Part II: Exploration, Self-Localization and Map Building
Authors: Victorino Alessandro Corrêa , Rives Patrick , Borrelly Jean-Jacques
Published: November 2003

This paper is the second part of the authors’ contribution on the topic of safe navigation for indoor mobile robots. It presents a new solution to the exploration, self-localization and map building problem taking advantage of the sensor-based navigation framework presented in Part I: A Sensor-Based Navigation Framework. The model of the indoor environment is structured as a hybrid representation, both topological and geometrical, which is incrementally built during the exploration task. The topological aspect of the model captures the connectivity and accessibility of the different places in the environment, and the geometrical model holds up an accurate robot localization and map building method. To overcome the problem of drift inherited to the odometry when the robot navigates in large-scale environments, a new dead-reckoning method is proposed combining laser readings and feedback control inputs. Embedding the selflocalization and map building problem in a sensor-based navigation framework improves both the quality and the robustness of the representation built during the exploration phase and authorizes a further use to achieve safe navigation tasks successfully. Experiments are shown which confirm the interests of the proposed methodology.
Duchamp’s Wager: Disguise, the Play of Surface, and Disorder
Authors: Scanlan John
Published: November 2003

This article considers the notion of ‘play’ in the plastic arts as described by Johan Huizinga, its definitional relation to the materiality of the art object, and the way in which such a conception rests on a notion of aesthetic order that, after the work of Marcel Duchamp, could not be sustained. I argue that Duchamp’s readymadesforce a re-evaluation of plasticity (and thus of Huizinga’s definition of play), and introduce a permanent revolution of plasticity, which in social and intellectual terms must be considered as the expression of an essential disorder underlying all appearances. It is further argued that Duchamp achieved this by employing strategies of disguise in order to lay bare the epistemic play of surfaces, and thus the contingency of knowledge and identity. Duchamp’s wager was that changing fashions in art revealed that it was neither formal presentation nor skill that defined art, but rather some connection to a hidden realm of disorder, and that this connection could be found, and repeatedly renewed, by ensuring that the art ‘object’ was received as an uncertain bequest.
China, the USA and the South China Sea Conflicts
Authors: To Lee Lai
Published: November 2003

This article focuses on China's strategy in dealing with the US factor in the South China Sea conflicts. While the USA is not directly involved in the South China Sea quagmire, its concern with the security of the sea-lanes and its insistence that peaceful means must be used to solve the region's problems have cautioned China to tread carefully in its plans to recover its ‘lost territories’. China would like to see ASEAN and the individual ASEAN claimant states weanedoff their reliance on Washington. However, US surveillance and military power, particularly in the post-11 September period, play an important role in ensuring that disputes in the South China Sea do not escalate to unacceptable levels. It seems likely that the impasse in the discussions on the South China Sea will continue for some time.
Dynamics of a Chain of Springs with Nonconvex Potential Energy
Authors: Cardin Franco , Favretti Marco
Published: November 2003

We study the dynamics of a discretized model of an elastic bar in a hard device formed by a chain of point masses connected by nonlinear springs whose total length is a controlled parameter. We compare the description of the system dynamics given by the first-order (gradient) dynamics, the second-order (Newtonian) dumped dynamics and the Relaxation Oscillation Theory. Using a technique based on Liapunov's second method, we prove a dynamic stability result concerning the above-mentioned ODEs.
Optorsim: A Grid Simulator for Studying Dynamic Data Replication Strategies
Authors: Bell William H. , Cameron David G. , Millar A. Paul , Capozza Luigi , Stockinger Kurt , Zini Floriano
Published: November 2003

Computational grids process large, computationally intensive problems on small data sets. In contrast, data grids process large computational problems that in turn require evaluating, mining and producing large amounts of data. Replication, creating geographically disparate identical copies of data, is regarded as one of the major optimization techniques for reducing data access costs. In this paper, several replication algorithms are discussed. These algorithms were studied using the Grid simulator: OptorSim. OptorSim provides a modular framework within which optimization strategies can be studied under different Grid configurations. The goal is to explore the stability and transient behaviour of selected optimization techniques. We detail the design and implementation of OptorSim and analyze various replication algorithms based on different Grid workloads.
Taming Labour’s MEPs
Authors: Messmer William B.
Published: November 2003

The national party leaders of Europe, sitting in separate national parliaments from their party’s Members of the European Parliament (MEPs), normally have difficulty influencing MEP policy decisions. This article, after pointing out the obstacles which minimize national party influence, analyzes a new and largely unacknowledged system of MEP coordination and control developed by the British Labour Party. Using data from interviews with Labour’s MEPs, the article concludes that Labour’s leaders have created an influential system of rewards and sanctions that have encouraged a closer and more disciplined relationship in this dualparliamentary setting.
The Nationalization of Parties and Party Systems
Authors: Jones Mark P. , Mainwaring Scott
Published: November 2003

Political parties and party systems exhibit widely varying degrees of nationalization, that is the extent to which a party receives similar levels of electoral support throughout the country. The level of party nationalization has a prominent effect on such important factors as the survival of democracy, the types of issues that dominate political competition, legislative behaviour and public policy. In spite of its importance, party nationalization has been neglected in the comparative politics literature. Our article makes two contributions. First, it provides a measure of party and party system nationalization, based on the Gini coefficient, that is superior for comparative analysis to those employed to date. Second, it utilizes these measures to analyse nationalization in 17 democracies in the Americas, the first time nationalization has been examined empirically outside the advanced industrial democracies. The measure underscores the widely varying degrees in nationalization across party systems, within party systems over time, across parties within countries and within parties over time.
A Comparative Review of Early Forms of Object-Directed Play and Parent-Infant Play in Typical Infants and Young Children with Autism
Authors: Williams Emma
Published: November 2003

The article reviews the empirical evidence relating to the development of early solitary object and parent-infant play in typical infants and children diagnosed with autism. Whilst, collectively, the findings indicate that there may be both qualitative and quantitative differences in the early play of children with autism, relative to that of other children, it is also clear that significant gaps exist in our current knowledge. It is proposed that longitudinal studies, which make a detailed examination of the form and developmental trajectory of early play, are needed if we are to devise the most effective content, design and outcome measures for intervention programmes using play as a therapeutic medium.
A Review of Research into Pretend Play in Autism
Authors: Jarrold Christopher
Published: November 2003

Autism is currently diagnosed, in part at least, on the basis of problems in imagination. The article reviews the empirical evidence of difficulties in pretend play in autism, and focuses in particular on individuals’ ability to engage in pretence in free play conditions, to produce pretence in more structured situations, and to make sense of pretend actions carried out by another person. These data suggest that individuals with autism have a marked difficulty in producing pretend play, but one that is reduced by providing substantial structure to the play situation or by testing comprehension of pretence. The implications of these findings for theories of pretend play in autism, in terms of an inability to conceive of non-literal situations, a difficulty in imposing a pretend usage on an object, or a failure to gain a benefit from engaging in pretend play, are discussed.
The Domestication of New Technologies as a Set of Trials
Authors: Lehtonen Turo-Kimmo
Published: November 2003

This article examines the domestication of technologies by following different phases of adoption. These phases are studied as a set of trials in which the capabilities of humans and non-humans are tested in many ways. I will begin the article by investigating the period in which interest in a piece of technology is slowly aroused. This involves the collective assessment of the ‘need’ for an object and, before an actual acquisition is made, consultations with friends and relatives who can act as ‘warm specialists’. Next, I analyse the initial period of living with new technology: the way the technology in question needs to be fitted into pre-existing technological and human relationships. Finally, I examine the ways in which a technology that has become an integral part of everyday lifeslowly becomes less and less present until, at last, it seems to have been done away with. As a whole, the set of trials forms a general process of domestication whereby new user knowledge is created and the moral order of the household is negotiated recurrently.
Quality of Life in Goserelin-Treated Versus Cyclophosphamide + Methotrexate + Fluorouracil–Treated Premenopausal and Perimenopausal Patients With Node-Positive, Early Breast Cancer: The Zoladex Early Breast Cancer Research Association Trialists Group
Authors: de Haes H. , Olschewski M. , Kaufmann M. , Schumacher M. , Jonat W. , Sauerbrei W.
Published: November 2003

Purpose: To compare quality of life (QoL) in premenopausal and perimenopausal patients with node-positive, early breast cancer treated with the endocrine agent goserelin (Zoladex; AstraZeneca Pharmaceuticals LP, Wilmington, DE) or cyclophosphamide + methotrexate + fluorouracil (CMF).

Patients and Methods: Patients from 86 centers worldwide were randomly assigned to receive either goserelin (3.6 mg every 28 days for 2 years; n = 514) or CMF (six 28-day cycles; n = 496), and were included in the QoL study. QoL was assessed using a self-administered patient questionnaire that consisted of 39 items from the Rotterdam Symptom Checklist, including dimensions evaluating physical and psychological symptom distress, activities of daily living, hormonal effects, and an assessment of overall QoL.

Results: Early benefits were noted during months 3 to 6 of treatment, for goserelin compared with CMF. Significant differences were found for changes in overall QoL (eg, 6.96 ± 0.88 v 0.69 ± 0.92 at 6 months; P < .0001) and for physical symptom distress, activity levels, and “effort to cope with illness” dimensions. At 1, 2, and 3 years, there were no significant differences in overall QoL or specific QoL dimensions. Scores for hormonal symptoms were worse with goserelin during the 2-year goserelin treatment period; however, this trend was reversed at 3 years.

Conclusion: Goserelin offers improved overall QoL during the first 6 months of therapy compared with CMF chemotherapy in premenopausal and perimenopausal patients with early breast cancer. Coupled with equivalent efficacy in estrogen receptor-positive patients, these data support the use of goserelin as an alternative to CMF in premenopausal and perimenopausal patients with estrogen receptor-positive, node-positive early breast cancer.
Expression of Novel Neurotrophin-1/B-Cell Stimulating Factor-3 (NNT-1/BSF-3) in Murine Pituitary Folliculostellate TtT/GF Cells: Pituitary Adenylate Cyclase-Activating Polypeptide and Vasoactive Intestinal Peptide-Induced Stimulation of NNT-1/BSF-3 Is Mediated by Protein Kinase A, Protein Kinase C, and Extracellular-Signal-Regulated Kinase1/2 Pathways
Authors: Vlotides George , Zitzmann Kathrin , Hengge Sabine , Engelhardt Dieter , Stalla Gunter K. , Auernhammer Christoph J.
Published: November 2003

Novel neurotrophin-1/B cell stimulating factor-3 (NNT-1/BSF-3) is a gp130 cytokine potently stimulating corticotroph proopiomelanocortin gene expression and ACTH secretion by a Janus kinase-signal transducer and activator of transcription (JAK-STAT)-dependent mechanism. In the current study, we examined the regulation of NNT-1/BSF-3 mRNA expression in murine pituitary folliculostellate TtT/GF cells using Northern blot technique. A 5- to 9-fold and a 4- to 7-fold induction in NNT-1/BSF-3 mRNA expression was observed between 2 and 6 h stimulation with the protein kinase C (PKC) stimulus phorbol-12-myristate-13-acetate (100 nm) and the protein kinase A (PKA) stimulus Bu2cAMP (5 mm), respectively. Pituitary adenylate cyclase-activating polypeptide (PACAP-38, 50 nm) and vasoactive intestinal peptide (VIP, 50 nm) also stimulated NNT-1/BSF-3 mRNA expression 5- to 9-fold between 2 and 6 h. Preincubation with PKC and PKA inhibitors such as H-7 (20 μm), GF109203X (50 μm), and H-89 (50 μm) decreased the stimulatory effects of PACAP and VIP. Both PACAP-38 and VIP also rapidly induced ERK1/2 phosphorylation and their stimulatory effect on NNT-1/BSF-3 mRNA expression was reduced by the MAPK kinase/ERK kinase (MEK) inhibitor U0126 (10 μm). Dexamethasone (10−7m) was a potent inhibitor of phorbol-12-myristate-13-acetate-induced NNT-1/BSF-3 expression. RT-PCR analysis demonstrated TtT/GF cells to express the short and the hop variant but not the hip variant of the PACAP-1 receptor (PAC1-R). In addition, TtT/GF cells express the VIP/PACAP-2 receptor (VPAC2-R). In summary, NNT-1/BSF-3 is expressed in pituitary folliculostellate TtT/GF cells and induced by PKC-, PKA-, and ERK1/2-dependent mechanisms. The novel gp130 cytokine NNT-1/BSF-3 derived from folliculostellate cells might act as a paracrine neuroimmunoendocrine modulator of pituitary corticotroph function.
Adrenocorticotropin/3′,5′-Cyclic AMP-Mediated Transcription of the Scavenger akr1-b7 Gene in Adrenocortical Cells Is Dependent on Three Functionally Distinct Steroidogenic Factor-1-Responsive Elements
Authors: Val Pierre , Aigueperse Christelle , Ragazzon Bruno , Veyssière Georges , Lefrançois-Martinez Anne-Marie , Martinez Antoine
Published: November 2003

The akr1-b7 gene encodes a scavenger enzyme expressed in steroidogenic glands under pituitary control. In the zona fasciculata of the adrenal cortex where its expression is controlled by ACTH, AKR1-B7 detoxifies isocaproaldehyde produced during the first step of steroidogenesis. Three steroidogenic factor-1 (SF-1)-responsive elements (SFREs) are contained within the −510/+41 promoter region, which was previously demonstrated to drive gene expression in transgenic mice adrenal cortex. All these sequences bind at least SF-1 in Y1 adrenocortical cell nuclear extracts and can be activated by overexpression of this factor in HeLa cells. However, the three SFREs show distinct properties regarding akr1-b7 promoter activity in Y1 cells. Whereas the proximal −102 SFRE supports basal promoter activity, the −458 bona fide SFRE is essential for both basal promoter activity and cAMP responsiveness, although it is unresponsive to cAMP when isolated from its promoter context. This suggests that SF-1 is not a cAMP-responsive factor per se. The neighboring SFRE at −503 is a palindromic sequence that binds monomeric and heteromeric SF-1 as well as an adrenal-specific complex. Using MA-10 Leydig cells and Y1–10r9 mutant cells, we provide evidence that its activity in adrenocortical cells depends on the binding of the adrenal-specific factor, which is required for basal and cAMP-induced promoter activity. Furthermore, the −503 site has intrinsic cAMP-sensing ability in Y1 cells, which is correlated with increased adrenal-specific complex binding. Collectively, our results suggest that cAMP responsiveness of the akr1-b7 promoter is achieved through cooperation between the adrenal-specific factor bound to the −503 site and SF-1 bound to the −458 site.
Region-specific and stage-dependent regulation of Olig gene expression and oligodendrogenesis byNkx6.1homeodomain transcription factor
Authors: Liu Rugao , Cai Jun , Hu Xuemei , Tan Min , Qi Yingchuan , German Michael , Rubenstein John , Sander Maike , Qiu Mengsheng
Published: November 2003

During early neural development, the Nkx6.1 homeodomain neural progenitor gene is specifically expressed in the ventral neural tube, and its activity is required for motoneuron generation in the spinal cord. We report that Nkx6.1 also controls oligodendrocyte development in the developing spinal cord, possibly by regulating Olig gene expression in the ventral neuroepithelium. In Nkx6.1 mutant spinal cords, expression of Olig2 in the motoneuron progenitor domain is diminished, and the generation and differentiation of oligodendrocytes are significantly delayed and reduced. The regulation of Olig gene expression by Nkx6.1 is stage dependent, as ectopic expression of Nkx6.1 in embryonic chicken spinal cord results in an induction of Olig2 expression at early stages, but an inhibition at later stages. Moreover, the regulation of Olig gene expression and oligodendrogenesis by Nkx6.1 also appears to be region specific. In the hindbrain, unlike in the spinal cord, Olig1and Olig2 can be expressed both inside and outside the Nkx6.1-expressing domains and oligodendrogenesis in this region is not dependent on Nkx6.1 activity.
Metabolic and cardiovascular adjustments of juvenile green turtles to seasonal changes in temperature and photoperiod
Authors: Southwood Amanda L. , Darveau Charles A. , Jones David R.
Published: November 2003

We measured activity levels, oxygen consumption, metabolic enzyme activity,breathing frequency, heart rate and blood chemistry variables of juvenile green turtles exposed to a laboratory simulation of subtropical winter and summer temperatures (17-26°C) and photoperiod (10.25 h:13.75 h to 14 h:10 h light:dark). The activity level of turtles had a significant effect on oxygen consumption and breathing frequency but there was no significant change in activity level between the summer and winter simulations. There was a moderate 24-27% decrease in oxygen consumption during exposure to winter conditions compared with summer conditions, but this difference was not statistically significant. Likewise, there was no statistically significant difference in breathing frequency between summer and winter simulations. Exposure to winter conditions did result in a significant decrease in activity of the aerobic enzyme citrate synthase. By contrast, activities of the glycolytic enzymes pyruvate kinase and lactate dehydrogenase were significantly higher in tissue collected during exposure to winter conditions compared with summer conditions. Citrate synthase, pyruvate kinase and lactate dehydrogenase had relatively low thermal dependence over the range of assay temperatures (15-30°C; Q10=1.44-1.69). Heart rate was 46-48%lower during the winter simulation compared with the summer simulation, and this difference was statistically significant. Exposure to winter conditions resulted in a significant decrease in plasma thyroxine and plasma proteins and a significant increase in plasma creatine phosphokinase and hematocrit. Overall, our results suggest that green turtles have a relatively low thermal dependence of metabolic rate over the range of temperatures commonly experienced at tropical to subtropical latitudes, a trait which allows them to maintain activity year-round.
The metabolic cost of avian egg formation: possible impact of yolk precursor production?
Authors: Vézina François , Salvante Katrina G. , Williams Tony D.
Published: November 2003

Little is known about the energy costs of egg production in birds. We showed in previous papers that, during egg production, European starlings(Sturnus vulgaris) undergo a 22% increase in resting metabolic rate(RMR) and that the maintenance and activity costs of the oviduct are responsible for 18% of the variation in elevated laying RMR. Therefore, other energy-consuming physiological mechanisms must be responsible for the remaining unexplained variation in elevated laying RMR. Yolk precursor[vitellogenin (VTG) and very-low-density lipoprotein (VLDL)] production is likely to be costly because it signifies a marked increase in the biosynthetic activity of the liver. We documented the pattern of yolk precursor production in response to daily injections of 17β-estradiol (E2) in zebra finches (Taeniopygia guttata). Based on this pattern we carried out an experiment in order to evaluate the metabolic costs of producing VTG and VLDL. Our E2 treatment resulted in a significant increase in plasma VTG and VLDL levels within the natural breeding range for the species. Although RMR was measured during the period of active hepatic yolk precursor production, it did not differ significantly within individuals in response to the treatment or when comparing E2-treated birds with sham-injected birds. This could mean that yolk precursor production represents low energy investment. However, we discuss these results in light of possible adjustments between organs that could result in energy compensation.
Chitin metabolism in insects: structure, function and regulation of chitin synthases and chitinases
Authors: Merzendorfer Hans , Zimoch Lars
Published: November 2003

Chitin is one of the most important biopolymers in nature. It is mainly produced by fungi, arthropods and nematodes. In insects, it functions as scaffold material, supporting the cuticles of the epidermis and trachea as well as the peritrophic matrices lining the gut epithelium. Insect growth and morphogenesis are strictly dependent on the capability to remodel chitin-containing structures. For this purpose, insects repeatedly produce chitin synthases and chitinolytic enzymes in different tissues. Coordination of chitin synthesis and its degradation requires strict control of the participating enzymes during development. In this review, we will summarize recent advances in understanding chitin synthesis and its degradation in insects.
A Novel Bisthienylethene as Acidichromic and Photochromic Yellow Dye
Authors: Luo Qianfu , Li Xiaochuan , Jing Shuping , Zhu Weihong , Tian He
Published: November 2003

A novel bisthienylethene as yellow colour photochromic and acidichromic dye has been prepared by a simple and low cost route, and its PC film shows a fast response reversible colour change between colourless and yellow colour by exposure to gaseous acid and ammonia.
New BEDT-TTF-based Organic Conductor Including an Organic Anion Derived from the TEMPO Radical, α-(BEDT-TTF)3(TEMPO–NHCOCH2SO3)2·6H2O
Authors: Akutsu Hiroki , Yamada Jun-ichi , Nakatsuji Shin’ichi
Published: November 2003

We report the genuine-organic magnetic conductor including organic free radical as a part of a counter anion, α-(BEDT-TTF)3(TEMPO–NHCOCH2SO3)2·6H2O, which consists of the conducting layers of the BEDT-TTF cations arranged in the α-packing mode and the magnetic layers of the TEMPO–NHCOCH2SO3 anions with water molecules alternatively along the c axis. In the magnetic layer, TEMPO groups gather to form a 1-D ferromagnetic network. The salt is semiconductive (ρRT = 5.1 Ω·cm and Ea = 0.050 eV) and its temperature-dependent susceptibility obeys the 1-D ferromagnetic Heisenberg model (C = 0.380 emu/mol K and J = +0.42 K).
Synthesis and Formation of Supramolecular Spherical Aggregates from Poly(benzyl ether) Dendrimers Having 21-Oxoporphyrin Core
Authors: Kumaresan D , Ravikanth M
Published: November 2003

Synthesis of second generation poly(benzyl ether) dendrimers having N3O porphyrin at its core and the first observation of large micro-meter sized spherical aggregates as confirmed by optical microscopy and AFM analysis are reported.
Photoinduced Dithiolation of Fullerene[60] with Dendrimer Disulfide
Authors: Takaguchi Yutaka , Katayose Yoshiaki , Yanagimoto Yasushi , Motoyoshiya Jiro , Aoyama Hiromu , Wakahara Takatsugu , Maeda Yutaka , Akasaka Takeshi
Published: November 2003

A new fullerodendrimer having fullerene–sulfur bonds as a linkage was prepared by the use of a binary system of organic dichalcogenide. Aggregation of the fullerodendrimer on mica surface was observed by atomic force microscopy (AFM) experiment.
Endoscopic treatment of an ethmoidal solitary fibrous tumour
Authors: Pasquini Ernesto , Cantaroni Cosetta , Salfi Nunzio , Tamburini Gabriel , Marchi Chiara , Sciarretta Vittorio
Published: November 2003

Solitary fibrous tumours are rare neoplasms, which occur most frequently during adulthood at the level of the pleura. Recently, these tumours have been demonstrated in extraserosal sites such as the nasal cavity. A case of a solitary fibrous tumour arising at the level of the ethmoid and presenting in a 54-year-old woman, is reported. The tumour was removed using an endonasal endoscopic approach that permitted the monobloc excision of the lesion. The patient is without evidence of disease 18 months after surgery.
Sialolithiasis in the sublingual gland
Authors: Hong Ki Hwan , Yang Yoon Soo
Published: November 2003

Sialolithiasis is a major cause of salivary gland dysfunction. The submandibular gland is the most common site followed by the parotid gland. The sublingual gland and minor glands are very rare sites for stone formation. This paper describes a case of multiple sialoliths arising in the sublingual gland. They presented on the right floor of the mouth. The sublingual gland and sialoliths were completely removed with careful preservation of the lingual nerve and Wharton’s duct. This was an uncommon sialolithiasis of the sublingual gland in a 14-year-old female.
Revenue Premium as an Outcome Measure of Brand Equity
Authors: Ailawadi Kusum L. , Lehmann Donald R. , Neslin Scott A.
Published: November 2003

The authors propose that the revenue premium a brand generates compared with that of a private label product is a simple, objective, and managerially useful product-market measure of brand equity. The authors provide the conceptual basis for the measure, compute it for brands in several packaged goods categories, and test its validity. The empirical analysis shows that the measure is reliable and reflects real changes in brand health over time. It correlates well with other equity measures, and the measure's association with a brand's advertising and promotion activity, price sensitivity, and perceived category risk is consistent with theory.
Cell cycle and behaviour in Euplotes crassus: an attempt at describing the biological relationship between its cellular and organismic natures
Authors: Banchetti Rosalba , Fosella Tiziana , Vazzoloretto Simona , Erra Fabrizio
Published: November 2003

The two‐faced nature of protozoa allowed us to study the relationship between cell cycle and behaviour in Euplotes crassus; the former represents one of the most typical cellular traits, the latter is one of the most significant characteristics of an organism. Dividing cells of E. crassus were isolated on a slide and recorded for 11 h: the classic ethographic parameters were calculated every 60 min. The percentage of mobile cells went from 0–100% in the first 2.5 h. This value was maintained for 6.5 h, but from 9 h the value began to drop, reaching 0% at 11 h. The relative frequency of leftward arcs was very high in the first hour, the radius and length of the arcs increased from 1–7 h; velocity showed a similar trend, peaking at 7 h. All our results showed that the behaviour of this ciliate is heavily affected by its cell‐division cycle.
Bi‐directional mechanical properties of the human forearm interosseous ligament
Authors: Stabile Kathryne J. , Pfaeffle Jamie , Weiss Jeffrey A. , Fischer Kenneth , Tomaino Matthew M.
Published: November 2003

Interest in reconstruction of the interosseous ligament (IOL) of the forearm in the setting of longitudinal radio‐ulnar dissociation has increased in recent years with hopes of improving clinical outcomes. This increased interest has been accompanied by research on biomechanics of the IOL. However, little is known about stress and strain in the IOL under externally applied forearm loads. This information is needed to help guide reconstruction. Mechanical properties of the IOL are needed to properly model the IOL for analyses such as finite element models. The objective of this study was to document the bi‐directional mechanical properties along the fiber direction (longitudinal) and perpendicular to the fiber direction (transverse). Twenty specimens were mounted in a materials testing machine to perform preconditioning and a load to failure tensile test in each direction. Strain markers on the surface of the specimens were tracked with a video system. Data analysis provided stress–strain curves for each specimen. The elastic moduli of longitudinal and transverse specimens were 515 ± 277 and 1.82 ± 2.93 MPa, respectively. The tensile strength and ultimate strain of longitudinal and transverse specimens were 54.1 ± 25.2 and 0.18 ± 0.20 and 16 ± 5% and 34 ± 32%, respectively. The bi‐directional mechanical properties of the IOL compared well with those published for the medial collateral ligament of the knee. The mechanical properties in the longitudinal direction were much greater than those in the transverse direction, which is indicative of the IOL's role in resisting longitudinal loading. The results of this study can be used to generate mathematical models of stress and strain in the IOL. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
How the fixation method stiffness and initial tension affect anterior load–displacement of the knee and tension in anterior cruciate ligament grafts: A study in cadaveric knees using a double‐loop hamstrings graft
Authors: Eagar Paul , Hull M. L. , Howell S. M.
Published: November 2003

There were two objectives to this study. The first was to investigate the relationship of graft fixation stiffness and graft initial tension on the anterior load–displacement behavior of knees reconstructed with a double‐loop hamstrings tendon graft. The second was to determine the corresponding graft tensions at 225 N of anterior force applied to the knee. To satisfy these objectives, the anterior‐load displacement curves were measured for seven cadaveric knees with the ACL intact at flexion angles ranging from 0° to 90°. The ACL was reconstructed in the same knees using a double‐loop hamstrings graft. A/P load–displacement curves of the knee and graft tension were measured as the fixation method stiffness and the initial tension applied at full extension were varied (25–326 N/mm and 25–300 N). The 0 N posterior limit (unloaded position of tibia) and the anterior laxity (difference between the 0 N posterior limit and 225 N anterior limit) were computed to characterize the A/P load–displacement of the intact and reconstructed knees. The key results were that the 0 N posterior limit of the tibia was insensitive to changes in stiffness (p > 0.6503) but that increasing initial tension caused increasing posterior subluxation of the tibia with respect to the femur (p = 0.0001). The tibia was subluxed posteriorly by 5–6 mm on average at high levels of initial tension. Both initial tension and stiffness significantly affected the anterior laxity (p = 0.0001 for both factors). Anterior laxity was restored closely to normal (i.e. <1 mm difference) by relatively high initial tension of 200 N in combination with low stiffness of 25 N/mm and by low initial tension of 25 N in combination with higher stiffness ranging between 94 and 326 N/mm. When anterior laxity is restored to normal using a high initial tension‐low stiffness combination however, the tibia undergoes a large posterior subluxation with respect to the femur in the unloaded state (approximately 5 mm) and a relatively high graft tension of 275 N is developed at 225 N of anterior force. Both the tibial subluxation and graft tension are reduced substantially with low initial tension–higher stiffness combinations because the amount of initial tension required to restore anterior laxity to normal is reduced by about 200 N. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Calibration of the Mars Pathfinder alpha proton X‐ray spectrometer
Authors: Foley C. Nicole , Economou Thanasis E. , Clayton Robert N. , Dietrich William
Published: November 2003

The chemical compositions of Martian rocks and soils examined with the alpha proton X‐ray spectrometer (APXS) during the Mars Pathfinder 1997 lander mission were not previously fully determined. Preliminary chemical results included major element abundances determined by the incomplete calibration of the X‐ray mode. The data collected from the alpha and proton detectors were not previously analyzed due to significant atmospheric contributions to the spectra. The backup instrument of the Pathfinder alpha proton X‐ray spectrometer flight instrument has been used to complete the instrument calibration under simulated Martian conditions at the University of Chicago. An APXS instrument has been used to create a Pathfinder calibration library to test the accuracy of all three instrument modes under simulated Martian conditions. This calibration library has been tested on a number of geologic standards. We have also corrected for instrument differences between the laboratory and flight units. Significant chemical results, somewhat different from those initially reported by Rieder et al. [1997a] and by Wänke et al. [2001], are reported by Foley et al. [2003] as a result of this reanalysis of the Pathfinder APXS data.
On partial thermoremanent magnetization tail checks in Thellier paleointensity determination
Authors: Yu Yongjae , Dunlop David J.
Published: November 2003

Coarse magnetite grains, of multidomain (MD) or large pseudo‐single‐domain (PSD) size (≥10 μm approximately), cause nonlinearity and other problems in paleomagnetic field intensity determination and can lead to spurious paleointensity values. One suggested method of detecting their presence is to carry out an additional zero‐field heating step following the acquisition of partial thermoremanent magnetization (pTRM) to check for complete demagnetization of the pTRM. Residual undemagnetized pTRMs (“pTRM tails”) are characteristic of MD and large PSD grains and cause nonideal behavior in Thellier‐type paleointensity experiments. We have measured pTRM tails in synthetic and natural magnetites of many sizes and domain states (including PSD and MD), starting from two different initial states. First, a thermally demagnetized sample was given a pTRM by cooling in a field H from the blocking temperature TB. The pTRM tail is the remanence ΔMptr remaining after zero‐field reheating to TB. ΔMptr is most prominent for large grain sizes and when TB ≥ 500°C. We next measured pTRM tails ΔMptr* produced in a Thellier paleointensity experiment. The initial state in this case is a total thermoremanent magnetization gradually reduced by double heatings (zero‐field followed by in‐field) to a set of increasing TB. For all synthetic and natural samples containing large PSD and MD magnetites, regardless of grain size or lithologic differences, ΔMptr is significant but ΔMptr* is negligible. That is, the pTRM tail checks are always zero in our model Thellier experiments. However, in practical paleointensity studies, the pTRM tail check method has been shown to be successful in detecting MD grains. The reason for these contrasting results is that our experiments were carried out with the field Hlab that produced pTRM equal in intensity and parallel to the field H that produced natural remanent magnetization (NRM). In this special situation the pTRM tail is completely masked. For the pTRM tail check method to be most effective, either Hlab should be applied at a large angle to the NRM direction or Hlab should be larger than (twice or more) the paleofield H. This will highlight the pTRM tail; in the first case by deflecting the apparent NRM direction after the tail‐check step, and in the second case by increasing the apparent NRM intensity.