bluuebunny/crossref_metadata_2025 huggingface dataset:
Local spin manipulation in ferromagnet-semiconductor hybrids
Authors: Halm S. , Bacher G. , Schuster E. , Keune W. , Sperl M. , Puls J. , Henneberger F.
Published: February 2007

The authors demonstrate the usage of magnetic fringe fields from nanoscale ferromagnets to locally control the spin degree of freedom in a semiconductor. Fringe fields stemming from Fe∕Tb multilayer ferromagnets induce a local, remanent out-of-plane magnetization in a ZnCdMnSe dilute magnetic semiconductor quantum well, which in turn aligns the spin of photogenerated carriers via sp-d exchange interaction. The authors achieve a local exciton spin polarization of up to ±12% at 4K without the need of an external magnetic field. The spin polarization can be controlled in sign and magnitude via the magnetization of the ferromagnet and is observable up to T=80K.
Excitation dependences of gain and carrier-induced refractive index change in quantum-dot lasers
Authors: Lorke M. , Jahnke F. , Chow W. W.
Published: February 2007

The excitation-density dependence of optical gain and refractive index changes in quantum-dot active media is investigated on the basis of a microscopic theory. Carrier-carrier Coulomb interaction and carrier-phonon interaction are treated on the level of a quantum-kinetic description. In the range of small optical gain the authors find small values of the α factor, while in the regime of gain saturation ∣α∣ increases drastically.
Atomic transport and integrity of Al2O3(2.0nm)∕HfO2(2.5nm) gate stacks on Si
Authors: Miotti L. , Pezzi R. P. , Copel M. , Krug C. , Baumvol I. J. R.
Published: February 2007

The integrity of Al2O3(2.0nm)∕HfO2(2.5nm)∕SiO2(<1nm)∕Si(001) stacks after rapid thermal annealing at temperature up to 1025°C was investigated. The structures were prepared by atomic layer deposition and atomic transport was accessed by profiling all elements in the system with subnanometric depth resolution, using medium and low energy ion scattering and narrow resonant nuclear reaction profiling. Al migration toward the stack/Si interface, Al loss by desorption from the surface, and Hf transport across the Al2O3 film layer toward the outermost surface were observed. The loss of oxygen from the stack is also noticeable, most probably caused by compound dissociation and desorption of oxygen containing species. The possible detrimental effects on device electrical properties of the observed presence of Hf at the outermost surface of the dielectric stack and of Al at the dielectric/Si interface are discussed.
Magnetic properties of strained single-walled carbon nanotubes
Authors: Zhang Zhuhua , Guo Wanlin
Published: February 2007

Strong effects of uniaxial and torsional strains on the magnetic properties of single-walled carbon nanotubes have been investigated by tight binding calculations and the Green function analyses. The strain-induced peaks of susceptibility are found in the carbon nanotubes, and paramagnetic-diamagnetic transition takes place at certain strains. The critical magnetic flux for semiconductor-metal transition changes linearly with strains depending on the chiralities of the tubes, mainly due to the tuning of the Van Hove singularities by the coupling of strains and magnetic flux. The positive and negative strain effects are asymmetrical in chiral tubes.
Low-temperature electrical characteristics of Bi3.15Nd0.85Ti3O12 thin films
Authors: Wu Di , Yuan Guoliang , Li Aidong
Published: February 2007

Ferroelectric and dielectric characteristics of Bi3.15Nd0.85Ti3O12 ferroelectric thin films were studied at temperatures from 296 down to 100K. The temperature dependence of these characteristics was discussed in terms of the Rayleigh model. Although the Rayleigh law fits well the dielectric data below 140K, it cannot describe the data at higher temperatures, where a mechanism contributes to the dielectric constant without producing losses. This mechanism may probably be related to bending of domain walls pinned by two nearest obstacles. The contribution from such bending is frozen out at low temperatures due to enhanced domain pinning.
Hologram replication technique in glass plates using corona charging
Authors: Sakai Daisuke , Harada Kenji , Kamemaru Shun-ichi , Fukuda Takashi
Published: February 2007

The authors propose a technique of recording in glass plates using corona charging. The recording material used in this study is conventional soda-lime glass. A surface-relief hologram on an azobenzene polymer film coated on a glass plate can be recorded as an electric charge distribution in the glass plate using corona charging. The hologram recorded in the glass plate can be reconstructed as a surface-relief structure on a fresh azobenzene polymer film coated on the glass plate, again using corona charging.
Splenic lesions: FNA findings in 48 cases
Authors: Kumar P. V. , Monabati A. , Raseki A. R. , Arshadi C. , Malek‐Hosseini S. A. , Talei A. R. , Sadeghi E.
Published: February 2007

Objective:  To study fine needle aspiration (FNA) cytological findings of splenic lesions and assess the role of FNA in the diagnosis of splenomegaly or splenic tumours.

Methods:  This study consisted of 48 cases, 25 males and 23 females. The ages ranged between 3 and 71 years. Most of these cases were aspirated under ultrasonographic guidance and a small number were also aspirated directly by using a 22‐ to 23‐gauge needles. The smears were stained with Wright–Giemsa and Papanicolaou methods. Special stains were used whenever necessary.

Results:  In this study 14 cases were diagnosed as lymphoma‐leukaemia, 7 cases as tuberculosis, 12 cases as kala‐azar, 2 cases as hydatid cyst, 3 cases as storage diseases, 3 cases as simple cyst, 2 cases as myeloproliferative disorders, 2 cases as malignant tumours and 3 cases as hamartomas (these were wrongly diagnosed as malignant tumours).

Conclusion:  Splenic aspiration is a safe procedure and is very useful in the diagnosis of parasitic and infectious diseases, especially in endemic countries like Iran.
Oviposition decreased in response to enriched water: a field study of the pitcher‐plant mosquito, Wyeomyia smithii
Authors: HOEKMAN DAVID , TERHORST CASEY , BAUER ALLISON , BRAUN SARAH , GIGNAC PAUL , HOPKINS ROBIN , JOSHI SONALI , LASKIS KRISTINA , SANSCRAINTE NEIL , TRAVIS JOSEPH , MILLER THOMAS E.
Published: February 2007

Abstract 1. Environmental cues are known to influence oviposition behaviour in mosquitoes, with important consequences for larval survival and insect population dynamics. Enriched microhabitats have been shown to be preferred oviposition sites.

2. In a field experiment designed to determine whether ovipositing mosquitoes are sensitive to different levels of nutrient enrichment, new pitcher‐plant (Sarracenia purpurea) leaves were opened and enriched with 0, 2, or 20 dead ants, and the number of pitcher‐plant mosquito (Wyeomyia smithii) larvae resulting from subsequent oviposition were measured.

3. Oviposition rates were higher in leaves with low levels of enrichment (0 and 2 ants per leaf), although larval development was enhanced at the highest enrichment level.

4. Results suggest that, although these mosquito larvae are nutrient limited, ovipositing females preferentially avoid highly enriched leaves. This counterintuitive result may be due to low oxygen concentrations or a masked cue in enriched leaves, and contrasts with other oviposition studies.
Gall wasps and their parasitoids in cork oak fragmented forests
Authors: CHUST GUILLEM , GARBIN LUCAS , PUJADE‐VILLAR JULI
Published: February 2007

Abstract 1. This paper explores the potential effects of host‐plant fragmentation on cork oak gall wasp populations (Cynipidae, Hymenoptera) and on their predators, lethal inquilines, and parasitoids. To address this objective, galls were collected across a gradient of cork oak (Quercus suber) forest fragmentation in the East Pyrenees (Albera, Spain), and they were incubated to obtain the parasitism rates.

2. Two hypotheses were tested: (1) Host‐plant fragmentation may induce a decline in gall wasp populations because of area and isolation effects on local extinction and dispersal; as a consequence of that, parasitoids may decline even more strongly in fragmented habitats than their prey. (2) Host‐plant fragmentation may cause a decline in gall wasp parasitoid populations that, in turn, can lead to an ecological release in their prey populations.

3. Among the eight cork oak gall wasps sampled in the study area of Albera, the gall abundances of three species (Callirhytis glandium, Callirhytis rufescens, and Andricus hispanicus) were significantly related to forest fragmentation. The overall abundance of gall wasps was affected by a radius of ≈ 890 m surrounding landscape, presenting constant abundances with forest loss until forest cover is reduced at ≈ 40%; below that value the abundance increased rapidly. Three inquilines and 23 parasitoids species were recorded after gall incubation. In 25 cases, species of inquilines and parasitoids were newly recorded for the corresponding host in the Iberian peninsula.

4. Although the overall parasitism rate was high (1.1), it was uncorrelated with fragmentation and with overall cynipid abundance. These results indicate that host‐plant fragmentation was correlated with higher abundance of gall wasps, whereas the parasitism rate could not explain this hyper‐abundance in small forest fragments.
Postoperative recovery: a concept analysis
Authors: Allvin Renée , Berg Katarina , Idvall Ewa , Nilsson Ulrica
Published: February 2007

Aim. This paper presents a concept analysis of the phenomenon of postoperative recovery.

Background. Each year, millions of patients throughout the world undergo surgical procedures. Although postoperative recovery is commonly used as an outcome of surgery, it is difficult to identify a standard definition.

Method. Walker and Avant's concept analysis approach was used. Literature retrieved from MEDLINE and CINAHL databases for English language papers published from 1982 to 2005 was used for the analysis.

Findings. The theoretical definition developed points out that postoperative recovery is an energy‐requiring process of returning to normality and wholeness. It is defined by comparative standards, achieved by regaining control over physical, psychological, social and habitual functions, and results in a return to preoperative level of independence/dependency in activities of daily living and optimum level of psychological well‐being.

Conclusion. The concept of postoperative recovery lacks clarity, both in its meaning in relation to postoperative recovery to healthcare professionals in their care for surgical patients, and in the understanding of what researchers in this area really intend to investigate. The theoretical definition we have developed may be useful but needs to be further explored.
Increasing vigilance on the medical/surgical floor to improve patient safety
Authors: Jacobs Joshua L. , Apatov Nathaniel , Glei Matthew
Published: February 2007

Aim.  This paper reports a study designed to assess an automated non‐invasive, patient vigilance system, the LG1TM system, for determining heart rate and respiration rate. The study uses collected data to optimize the LG1TM’s alert management scheme for medical/surgical wards.

Background.  Thousands of patients die unnecessarily each year because of compromised patient safety in hospitals. Economic pressures to reduce hospitalization costs, exacerbated by increasing nursing shortages, have created a need for new approaches to patient vigilance. Advanced technologies may help nurses to provide high‐quality care while controlling costs and improving patient safety.

Methods.  Heart and respiration waveforms from 287 patients were captured by sensor arrays embedded in the mattress coverlets of their beds. No real‐time monitoring was performed. Raw data were processed by proprietary algorithms and compared with data captured by a standard reference device. Alert performance was verified by hand‐scoring the signal data and matching it against clinical events observed through a systematic review of each patient's medical record. The data were collected between June 2004 and February 2005.

Results.  Experimental algorithms for heart rate had an accuracy of −1·47 (sd 1·90) and a precision of 4·60 (sd 2·46). Respiration rate algorithms showed an accuracy of −0·94 (sd 1·26) and a precision of 4·02 (sd 1·17). Algorithms identified 178 true‐positive physiological alerts on 15 patients. None of the events was deemed clinically significant at chart review. The combined false‐positive alert rate for the algorithms was 0·007 events per hour.

Conclusion.  This study demonstrates the accuracy and precision of the signal processing algorithms in the LG1TM system. Future work will focus on assessing the system's impact on patient outcomes and its integration into the nursing workflow.
Overall self‐rated health: a new quality indicator for primary care
Authors: Rohrer James E. , Young Rodney , Sicola Virginia , Houston Margaret
Published: February 2007

Rationale, aims and objectives  Patient ‘empowerment’ gives patients choices about their own care and about the outcomes they would most prefer. Many patients can be presumed to regard overall self‐rated health as an important outcome. Therefore, overall self‐rated health can be considered a relevant and important outcome measure for a patient‐centred medical clinic. The purpose of this study was to use this new outcome measure as a dependent variable and to test the hypothesis that patients who are confident about their ability to manage their health will have better health, in comparison to more dependent patients.

Methods  We conducted a randomized cross‐sectional postal survey of 500 veteran patients from the Panhandle of Texas and the surrounding areas; and 302 participated in the study. Multiple logistic regression analysis was used to test the hypothesis that health confidence is positively related to self‐rated health, controlling for obesity, cigarette smoking and participation in recreational activities.

Results  Veterans who strongly disagreed with the statement that they usually could overcome illnesses on their own were less likely to report good, very good or excellent self‐rated health (adjusted odds ratio = 0.25).

Conclusions  Overall self‐rated health as measured by a single question proved to be significantly related to behavioural risk factors in this sample of primary care patients, attesting to its validity as an outcome indicator. Furthermore, health confidence was associated with better health. Most primary providers believe that they can, through good communication and providing self‐care tools, increase healthy behaviours in their patients. If we are indeed able to increase health confidence in our patients, this study would suggest that self‐rated health would improve.
An analysis of the evidence‐practice continuum: is surgery for obstructive sleep apnoea contraindicated?
Authors: Elshaug Adam G. , Moss John R. , Southcott Anne Marie , Hiller Janet E.
Published: February 2007

Rationale, aims and objectives  Currently there are multiple surgical interventions utilized in the treatment of adult obstructive sleep apnoea (OSA). The role of these operations remains controversial, with perspectives on treatment efficacy varying considerably. Despite this, their use is proliferating.

Objectives  In this paper, we present the degree of variability that occurs in the application of these procedures, and examine the effectiveness of surgical intervention as a treatment for OSA.

Method  A multi‐centre retrospective clinical audit of consecutive, unselected surgical cases presenting at the sleep disorder clinics of two teaching hospitals in a major Australian city. Patients acted as their own historical controls, undergoing polysomnography pre and post surgery to gauge effectiveness.

Results  On variability demonstrate 94 individuals in this cohort received 220 individual upper airway surgical procedures, 184 occurred in their first operation (mean 2.5 per person; range 1–7) and 36 occurred in a second operation (n = 18; cumulative mean of 4 per person; range 3–7). These 94 individuals received 41 varying combinations of surgery. Results on effectiveness demonstrate an overall physiological success rate of 13% (87% fail). One operation reduced OSA severity by 20% (patients still had severe OSA), and two operations by 35% (still moderate OSA). In contrast, conventional Continuous Positive Airway Pressure therapy controlled OSA (n = 64).

Conclusions  This case study demonstrates substantial procedural variability and limited effectiveness. This raises questions as to the quality of care, the treatment‐derived health outcomes of this population and of efficient resource allocation. This issue requires greater policy attention.
Effect of hexokinase activity on tomato root metabolism during prolonged hypoxia
Authors: GHARBI IMENE , RICARD BERENICE , ROLIN DOMINIQUE , MAUCOURT MICHAEL , ANDRIEU MARIE‐HELENE , BIZID ESSIA , SMITI SAMIRA , BROUQUISSE RENAUD
Published: February 2007

Hypoxically induced tolerance to anoxia in roots of tomato (Solanum lycopersicum) was previously shown to depend on sucrose and the induction of sucrose synthase. In contrast to maize, root hexokinase (HXK) activities did not increase during hypoxia and glucose was unable to sustain glycolytic flux under anoxia. In this paper, we asked whether hypoxic metabolism in roots would be altered in transgenic tomato plants overexpressing either a plant (Arabidopsis) or a yeast (Saccharomyces cerevisiae) HXK and whether such modifications could be related to improved energy metabolism and consequently root tolerance under anoxia. Tomato plants grown hydroponically with shoots always maintained in air were submitted to a 7 d hypoxic treatment applied by stopping air bubbling. A combination of techniques including 1H‐nuclear magnetic resonance spectroscopy, RT‐PCR and enzyme analyses was used to obtain a broad picture of hypoxic root metabolism. In normoxic conditions, HXK overexpression resulted in higher ADP and AMP levels only in roots of AtHXK1 transgenic plants. During hypoxic treatment, oxygen levels in the hydroponic tank decreased rapidly to 5 kPa within the first 2 d and then remained at 5 kPa throughout the 7 d experiment. Oxygen levels were similar at 5 and 20 cm below the water surface. A decline of the adenylate energy status was observed after 2 d of hypoxic treatment, with a further decrease by 7 d in roots of non‐transgenic (WT) and ScHXK2, but not in AtHXK1 transgenic plants. Sucrose synthase activity increased to comparably higher levels at 7 d of hypoxic treatment in WT and ScHXK2 compared with AtHXK1 roots. Differences between WT and the transgenic plants are discussed with respect to the metabolic response to low (hypoxia) but not zero (anoxia) oxygen.
Apical leaf necrosis and leaf nitrogen dynamics in diseased leaves: a model study
Authors: Van Den Berg F. , Robert C. , Shaw M. W. , Van Den Bosch F.
Published: February 2007

Apical leaf necrosis is a physiological process related to nitrogen (N) dynamics in the leaf. Pathogens use leaf nutrients and can thus accelerate this physiological apical necrosis. This process differs from necrosis occurring around pathogen lesions (lesion‐induced necrosis), which is a direct result of the interaction between pathogen hyphae and leaf cells. This paper primarily concentrates on apical necrosis, only incorporating lesion‐induced necrosis by necessity. The relationship between pathogen dynamics and physiological apical leaf necrosis is modelled through leaf nitrogen dynamics. The specific case of Puccinia triticina infections on Triticum aestivum flag leaves is studied. In the model, conversion of indirectly available N in the form of, for example, leaf cell proteins (N2(t)) into directly available N (N1(t), i.e. the form of N that can directly be used by either pathogen or plant sinks) results in apical necrosis. The model reproduces observed trends of disease severity, apical necrosis and green leaf area (GLA) and leaf N dynamics of uninfected and infected leaves. Decreasing the initial amount of directly available N results in earlier necrosis onset and longer necrosis duration. Decreasing the initial amount of indirectly available N, has no effect on necrosis onset and shortens necrosis duration. The model could be used to develop hypotheses on how the disease‐GLA relation affects yield loss, which can be tested experimentally. Upon incorporation into crop simulation models, the model might provide a tool to more accurately estimate crop yield and effects of disease management strategies in crops sensitive to fungal pathogens.
Population structure of poplar rustMelampsora larici‐populinain the UK inferred from AFLP
Authors: Pei M. H. , Bayon C. , Ruiz C. , Tubby I.
Published: February 2007

AFLP profiles were generated from poplar leaf rust (Melampsora larici‐populina) collected fromPopulus trichocarpacv. Trichobel at six sites in the UK in 2001. Of a total of 145 isolates, 121 were unique AFLP phenotypes. On one occasion, the same AFLP phenotype was found at two sites. The analysis indicated that 81·88% of the total variation was attributable to differences among individuals within replicate plots, 3·47% to differences among plots within sites and 14·65% to differences among sites. Weir & Cockerham's θ was calculated as 0·138 and θB, the Bayesian analogue ofFST, as 0·146. Overall, there was sufficient gene flow among different sites to prevent genetic drift, asNmwas calculated as 1·562 using θ and as 1·462 using θB.Nei's genetic distance and population‐assignment test indicated that the rust from a site in north‐east England was differentiated from those from other sites. There was no significant correlation between genetic and geographical distances. The results indicate that sexual reproduction has a major influence on the relative lack of population structure ofM. larici‐populinain the UK.
Social Transfer of Predation Risk Information Reduces Food Locating Ability in European Minnows (Phoxinus phoxinus)
Authors: Johnsson Jörgen I. , Fredrik Sundström L.
Published: February 2007

Little is known about how food location ability of animals is affected by social information of predation risk. This question was therefore addressed in an experimental study where naïve ‘observer’ European minnows (Phoxinus phoxinus) were allowed to search for food in a maze in the presence or absence of a predator (Salmo trutta). Observer minnows were accompanied by conspecific demonstrators which had previously been trained in the same maze either in the presence or absence of the predator. Observer minnows were most likely to locate food when the predator was absent both during their trial and during the pre‐training of demonstrators. When demonstrators had been trained with predators, observer success in locating the food was halved, although they were never exposed to predation risk themselves. When observers were exposed to predation risk their probability of locating food was further reduced regardless of the experience of their demonstrators. Our results show that predation risk can affect the foraging ability of minnows both directly and indirectly through social information from conspecifics. We conclude that social information may influence and constrain individual behavioural decisions, especially in rapidly changing environments where private information is often insufficient.
Observational Evidences of Vocal Learning in Southern Elephant Seals: a Longitudinal Study
Authors: Sanvito Simona , Galimberti Filippo , Miller Edward H.
Published: February 2007

Vocal learning in mammals is sparsely documented, and there are few reports of vocal learning by wild mammals. In particular, no information based on longitudinal data for identified individuals exists, even for well‐studied highly social species in which vocal communication is an important aspect of social life. We present such information for the southern elephant seal (Mirounga leonina). We studied a small breeding population in the Falkland Islands over 8 yr (1995–2002). We recorded approx. 2400 agonistic vocalizations from approx. 285 different males, including many recorded over more than one breeding season (55 males were recorded for >2 yr and 29 were recorded throughout vocal development). Vocalizations are a key element of male agonistic behaviour in this species, the world's most polygynous vertebrate. For male agonistic vocalizations, we show that: (1) a limited number of discrete vocal types exists; (2) proportions of vocal types change over time; (3) observed trends of increase or decrease of vocal types are well explained by a process of vocal learning, in which younger peripheral males imitate vocal types of older more successful breeders.
Post‐copulatory Mounting Behavior of the West Indian Sweetpotato Weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae)
Authors: Sato Yukie , Kohama Tsuguo
Published: February 2007

Post‐copulatory associations between males and females have been found in a variety of insects and are often described as mate guarding. Males of the West Indian sweetpotato weevil Euscepes postfasciatus (Fairmaire) mount the female's back after copulation. Two hypotheses have been advanced to explain this behavior: mate guarding to prevent future copulations by rivals (hypothesis 1), and mate guarding to gain additional copulations (hypothesis 2). We conducted three experiments to test predictions from these hypotheses. Our results disproved hypothesis 1 because the duration of the post‐copulatory association was very brief in comparison with the length of the refractory phase all females showed after copulation. When we prevented females from resisting copulations during the post‐copulatory mounted phase males copulated again, while under normal conditions, a second copulation was never observed. This result may indicate the presence of a sexual conflict over mating. However, we propose an alternative interpretation of the result, namely that after mating, males test whether the copulation has successfully reduced female receptivity by attempting to remate. If females resist the mating, males leave.
All that Glisters is not Gold: Sensory Bias, Sexual Conflict and Nuptial Feeding in Insects and Spiders
Authors: Vahed Karim
Published: February 2007

It is becoming increasingly clear that the evolutionary interests of the sexes are often in conflict when it comes to mating. Sexual encounters involving nuptial gifts, however, have often been viewed as prime examples of sexual co‐operation, rather than conflict. In this review, I explore the proposition that nuptial gifts act as sensory traps: by exploiting the female's gustatory responses, the male may be able to entice females to accept superfluous matings and/or transfer greater volumes of ejaculate than are in the female's reproductive interests. Evidence suggests that the females’ sensory biases may have played an important role in shaping gift characteristics in at least four different systems, although relatively few forms of nuptial feeding have so far been examined from this perspective. I argue that gift composition is more likely to be tailored to increasing the attractiveness of the gift to the female and/or maximizing gift handling time than to suit the female's nutritional needs and that the fecundity‐enhancing benefits of nuptial gifts are often questionable and have been over‐stated in the literature. Fertilization biases associated with the female's attraction to the nuptial gift, however, could lead to in‐direct benefits for the female. On the other hand, nuptial feeding may also lead to significant costs to the female. Evidence suggests that some types of gift entice the female to mate, but it is not clear whether the resultant degree of polyandry is higher than optimal for the female. In other cases, evidence suggests that the gift enables the male to overcome the resistance of the female to accepting an extra large ejaculate and that large ejaculates are associated with longer post‐mating sexual refractory periods in the female. This could represent a cost to the female by delaying or preventing her from receiving the genetic benefits of polyandry. At present, it is not clear, however, whether such costs outweigh the potential benefits of nuptial feeding for the female.
Parametric Identification for a Truss Structure Using Axial Strain
Authors: Xu B. , Chen G. , Wu Z. S.
Published: February 2007

Abstract:  The increasing use of advanced sensing technologies such as optic fiber Bragg grating and embedded piezoelectric sensors necessitates the development of strain‐based identification methodologies. In this study, a three‐step neural networks based strategy, called direct soft parametric identification (DSPI), is presented to identify structural member stiffness and damping parameters directly from free vibration‐induced strain measurements. The rationality of the strain based DSPI methodology is explained and the theoretical basis for the construction of a strain‐based emulator neural network (SENN) and a parametric evaluation neural network (PENN) are described according to the discrete time solution of the state space equation of structural free vibration. The accuracy, robustness, and efficacy of the proposed strategy are examined using a truss structure with a known mass distribution. Numerical simulations indicate that the average relative errors of identified structural properties were less than 5% and relatively insensitive to measurement noises.
On Optimal Commodity Taxes When Consumption Is Time Consuming
Authors: GAHVARI FIROUZ
Published: February 2007

This paper studies the problem of optimal taxation of commodities when consumption is a time‐consuming activity. This is done under two distinct preference separability assumptions: between goods and labor supply, and between goods and leisure. It argues that with the labor separability, the traditional uniform taxation results of optimal tax theory continue to hold. With leisure separability, on the other hand, consumption time is a major ingredient of optimal tax rates. However, the relationship between consumption time and optimal tax rates depends crucially on the representation of the economy. In representative consumer economies, time differences determine the pattern of optimal tax rates so that goods whose consumption take more time are subjected to higher tax rates. When individuals have different earning abilities, redistributive, incentive, and efficiency considerations also come into play resulting in a complex relationship. The paper derives formulas for optimal commodity taxes in this case on the basis of three different tax structures: linear commodity taxes in combination with linear and nonlinear income taxes, and nonlinear commodity taxes in combination with nonlinear income taxes.
Asymmetric Equilibria in a Model with Costly Voting
Authors: DE SINOPOLI FRANCESCO , IANNANTUONI GIOVANNA
Published: February 2007

Most of the voting models limit their analysis to the investigation of symmetric equilibria where “similar” voters make “similar” voting decisions. In this paper we examine the validity of this restriction in a model with costly plurality voting. We first show that in any pure strategy equilibrium every two individuals who have the same preferences and participate in elections, would vote for the same candidate. However, this result does not hold for mixed strategies equilibria.
The Simple Economics of Bunching: Optimal Taxation with Quasi‐Linear Preferences
Authors: BOONE JAN , BOVENBERG LANS
Published: February 2007

This paper models unemployment as a binding nonnegativity constraint on hours worked in an optimal income tax problem with quasi‐linear preferences. We show that bunching of workers resulting from this binding constraint provides a more convincing description of the bottom of the labor market than bunching due to violation of the second‐order condition for individual optimization. Although a binding nonnegativity constraint destroys the closed form solution of optimal marginal tax rates, the optimal tax problem can be characterized in a two‐dimensional diagram in which comparative statics can be performed in straightforward fashion.
AFTERWORDS: AN INTRODUCTION TO ARTHUR DANTO'S PHILOSOPHIES OF HISTORY AND ART*
Authors: GOEHR LYDIA
Published: February 2007

This essay is written as an introductory essay to celebrate the third edition of Arthur Danto's Analytical Philosophy of History, first printed in 1965. It raises questions about what it means to write an introduction and whether it is possible to write an introduction‐given Danto's own philosophical theses on history, the essay pays special attention to the connections between Danto's philosophy of history, philosophy of art, and the other areas of his philosophy that he regards to be all of a piece. It considers the nature of analytical philosophy and its heyday in America in the postwar period, when, to some degree, it was used as an antidote to an ideology of history that had perverted some of the most influential claims in a philosophy of history developed in Germany (mostly by Hegel) around 1800.
INTELLECTUAL HISTORY, INCONCEIVABILITY, AND METHODOLOGICAL HOLISM1
Authors: MITROVIĆ BRANKO
Published: February 2007

The debate between individualism and holism in the philosophy of history pertains to the nature of the entities relied on in historical explanations. The question is whether explanations of historical items (for example, events, actions, artifacts) require the assumption that the collective historical entities (for example, civilizations, cultures, and so on) used in these explanations are (sometimes) conceived of as irreducible to the actions, thoughts, and beliefs of individual human beings. In this paper I analyze two methodological problems that holist explanations face in the writing of intellectual history. The first problem derives from the fact that holist explanations in intellectual history have to rely on the claim that certain beliefs were inconceivable to some individuals because they were members of specific collectives, whereas it is unclear how historical research can justify such claims when made from the holist position. The second problem pertains to the difficulties the holist position faces when it has to account for the novel properties of artifacts studied by intellectual history.
Ultrastructural localization of glycodelin oligosaccharides Le‐x and Le‐y in human seminal vesicles by immunogold staining
Authors: Piludu M. , Cossu M. , De Lisa A. , Piras M. , Lantini M. S.
Published: February 2007

Histo‐blood group antigens Le‐x and Le‐y are oligosaccharidic terminals that characterize many glycoproteins in the human tissues. In seminal plasma, they are expressed as part of the so‐called glycodelin S, which is suggested to regulate sperm capacitation/decapacitation. It has recently been demonstrated that the core protein of glycodelin S is secreted by seminal vesicles. Here we show that epithelial cells of human seminal vesicles also release the Le‐x and Le‐y antigens. The presence of these substances in secretory material was revealed by means of an immunogold staining method in normal surgical samples. The results suggest that glycodelin S is secreted by seminal vesicles in its finished glycosylated form. Moreover, antigen reactivity was also revealed associated with plasma membranes.
Porosity of human mandibular condylar bone
Authors: Renders G. A. P. , Mulder L. , Van Ruijven L. J. , Van Eijden T. M. G. J.
Published: February 2007

Quantification of porosity and degree of mineralization of bone facilitates a better understanding of the possible effects of adaptive bone remodelling and the possible consequences for its mechanical properties. The present study set out first to give a three‐dimensional description of the cortical canalicular network in the human mandibular condyle, in order to obtain more information about the principal directions of stresses and strains during loading. Our second aim was to determine whether the amount of remodelling was larger in the trabecular bone than in cortical bone of the condyle and to establish whether the variation in the amount of remodelling was related to the surface area of the cortical canals and trabeculae. We hypothesized that there were differences in porosity and orientation of cortical canals between various cortical regions. In addition, as greater cortical and trabecular porosities are likely to coincide with a greater surface area of cortical canals and trabeculae available for osteoblastic and osteoclastic activity, we hypothesized that this surface area would be inversely proportional to the degree of mineralization of cortical and trabecular bone, respectively. Micro‐computed tomography was used to quantify porosity and mineralization in cortical and trabecular bone of ten human mandibular condyles. The cortical canals in the subchondral cortex of the condyle were orientated in the mediolateral direction, and in the anterior and posterior cortex in the superoinferior direction. Cortical porosity (average 3.5%) did not differ significantly between the cortical regions. It correlated significantly with the diameter and number of cortical canals, but not with cortical degree of mineralization. In trabecular bone (average porosity 79.3%) there was a significant negative correlation between surface area of the trabeculae and degree of mineralization; such a correlation was not found between the surface area of the cortical canals and the degree of mineralization of cortical bone. No relationship between trabecular and cortical porosity, nor between trabecular degree of mineralization and cortical degree of mineralization was found, suggesting that adaptive remodelling is independent and different between trabecular and cortical bone. We conclude (1) that the principal directions of stresses and strains are presumably directed mediolaterally in the subchondral cortex and superoinferiorly in the anterior and posterior cortex, (2) that the amount of remodelling is larger in the trabecular than in the cortical bone of the mandibular condyle; in trabecular bone variation in the amount of remodelling is related to the available surface area of the trabeculae.
Activation of stress‐related hypothalamic neuropeptide gene expression during morphine withdrawal
Authors: Nunez Cristina , Földes Anna , Laorden M. Luisa , Milanes M. Victoria , Kovács Krisztina J.
Published: February 2007

Morphine withdrawal results in serious affective and somatic symptoms including activation of the hypothalamo–pituitary–adrenocortical (HPA) axis. To reveal secretory, activational and transcriptional changes in the hypothalamus of morphine‐dependent rats during naloxone precipitated opioid withdrawal, we measured corticosterone secretion, c‐Fos induction and heteronuclear (hn)RNA levels of corticotropin‐releasing hormone (CRH) and arginine vasopressin (AVP) in naïve and morphine dependent animals injected with saline or 5 mg/kg naloxone. Naloxone precipitated morphine withdrawal resulted in a significant increase in corticosterone secretion and induction of neuronal activation in the hypothalamic paraventricular nucleus (PVH) 2 h after challenge. Using probes complementary to intronic sequences of genes encoding neuropeptides in parvocellular neurosecretory neurons of the PVH, we found robust increases in CRH and AVP hnRNAs in morphine dependent rats during naloxone precipitated withdrawal. Naïve rats and animals that were implanted with morphine pellets for 8 days did not display significant up‐regulation of ongoing neuropeptide expression in the parvocellular compartment of the PVH. In addition to hypophyseotropic neurons, naloxone precipitated withdrawal resulted in a marked activation in autonomic‐related projection neurons in PVH and in the magnocellular neurons in the PVH and supraoptic nuclei. These activations however were not associated with induction of CRH or AVP hnRNAs.
The β‐amyloid protein of Alzheimer’s disease binds to membrane lipids but does not bind to the α7 nicotinic acetylcholine receptor
Authors: Small David H. , Maksel Danuta , Kerr Megan L. , Ng Judy , Hou Xu , Chu Cindy , Mehrani Hossein , Unabia Sharon , Azari Michael F. , Loiacono Richard , Aguilar Marie‐Isabel , Chebib Mary
Published: February 2007

Accumulation of the amyloid protein (Aβ) in the brain is an important step in the pathogenesis of Alzheimer’s disease. However, the mechanism by which Aβ exerts its neurotoxic effect is largely unknown. It has been suggested that the peptide can bind to the α7 nicotinic acetylcholine receptor (α7nAChR). In this study, we examined the binding of Aβ1‐42 to endogenous and recombinantly expressed α7nAChRs. Aβ1‐42 did neither inhibit the specific binding of α7nAChR ligands to rat brain homogenate or slice preparations, nor did it influence the activity of α7nAChRs expressed in Xenopus oocytes. Similarly, Aβ1‐42 did not compete for α‐bungarotoxin‐binding sites on SH‐SY5Y cells stably expressing α7nAChRs. The effect of the Aβ1‐42 on tau phosphorylation was also examined. Although Aβ1‐42 altered tau phosphorylation in α7nAChR‐transfected SH‐SY5Y cells, the effect of the peptide was unrelated to α7nAChR expression or activity. Binding studies using surface plasmon resonance indicated that the majority of the Aβ bound to membrane lipid, rather than to a protein component. Fluorescence anisotropy experiments indicated that Aβ may disrupt membrane lipid structure or fluidity. We conclude that the effects of Aβ are unlikely to be mediated by direct binding to the α7nAChR. Instead, we speculate that Aβ may exert its effects by altering the packing of lipids within the plasma membrane, which could, in turn, influence the function of a variety of receptors and channels on the cell surface.
Neonatal Seizures: Eyes Open or Closed?
Authors: Bauder Florian , Wohlrab Gabriele , Schmitt Bernhard
Published: February 2007

Summary:  Purpose: It has been shown that persistent eye closure during paroxysmal events in infants makes seizures unlikely. Our study aims to assess whether this is also true in neonates.

Methods: We reviewed and classified all archived neonatal seizures in our video database, considering electroclinical seizures only and excluding electrographic seizures and clinical seizures without ictal change in EEG. We assessed whether eyes were open during the seizure. One hundred and thirty‐one electroclinical seizures (clonic, focal and generalized tonic, tonic–clonic, generalized myoclonic, subtle and spasms) in 46 neonates were included.

Results: In 115 (88%) seizures, eyes were open; in 10 seizures, they were closed; and in six seizures, eye opening could not be evaluated. All 10 seizures with persistent eye closure were clonic seizures.

Conclusions: Our data demonstrate that persistent eye closure during an event suggestive of a seizure in a newborn makes an electroclinical seizure unlikely.
EEG‐fMRI in Children with Pharmacoresistant Focal Epilepsy
Authors: De Tiège Xavier , Laufs Helmut , Boyd Stewart G. , Harkness William , Allen Philip J. , Clark Chris A. , Connelly Alan , Cross J. Helen
Published: February 2007

Summary:  Purpose: To evaluate the usefulness of EEG‐combined functional magnetic resonance imaging (EEG‐fMRI) to localize epileptogenic sources.

Methods: Six children (age 8–15 years) with lesional or nonlesional pharmacoresistant focal epilepsy were studied.

Results: We found significant activations in four children, activation and deactivation in one child, and widespread deactivation in another. In four children, activations colocalized with the presumed location of the epileptic focus, one of which was confirmed by intracranial EEG.

Conclusions: EEG‐fMRI is a promising tool to noninvasively localize epileptogenic regions in children with pharmacoresistant focal epilepsy.
Modulation of AMPA Receptors in Cultured Cortical Neurons Induced by the Antiepileptic Drug Levetiracetam
Authors: Carunchio Irene , Pieri Massimo , Ciotti Maria Teresa , Albo Federica , Zona Cristina
Published: February 2007

Summary: Purpose:The present study explores the hypothesis that the antiepileptic mechanism of action of levetiracetam (LEV) is related to effects on α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA) receptor channels in mouse cortical neurons in culture.

Methods:The neurons were subjected to the whole‐cell configuration of the patch‐clamp recording technique and were 8–12 days old in culture.

Results:Kainate elicited concentration‐dependent (EC50= 80 μM) inward currents in all the patched cells. LEV (5–200 μM) itself did not induce inward or outward currents on all patched neurons, whereas it was effective on the kainate‐ and AMPA‐induced current because it significantly decreased the amplitude of these currents. LEV was also able to significantly decrease the total membrane conductance during kainate perfusion, indicating that its effect was not dependent on the cellular voltage membrane potential. Further evidence that LEV modulated the ionotropic non‐NMDA receptors came from the analysis of miniature excitatory postsynaptic currents (mEPSCs). In fact, LEV significantly decreased both the amplitude and the frequency of mEPSCs, as shown by the relative cumulative distributions.

Conclusions:These results reveal that AMPA receptors are modulated by LEV because a significant decrease in the kainate‐ and AMPA‐induced currents and a decrease in amplitude and in frequency of mEPSCs have been observed in cortical neurons in culture. The described effect of LEV on AMPA receptors in cortical neurons is probably due to the etheromeric composition of the receptors and may be considered as a possible new antiepileptic mechanism of action.
Potential Factors That Affect Electrocardiographic Progression of Interatrial Block
Authors: Ariyarajah Vignendra , Kranis Mark , Apiyasawat Sirin , Spodick David H.
Published: February 2007

Introduction: Interatrial block (IAB; P wave ≥ 110 ms) is associated with atrial tachyarrhythmias and left atrial electromechanical dysfunction. This subtle abnormality is highly prevalent and may exist as partial (pIAB) or advanced IAB (aIAB). Indeed, theoretically pIAB could progress to aIAB with worsening interatrial conduction over time. However, this has been poorly investigated. We retrospectively appraised this phenomenon and also evaluated the influence of common clinical factors such as coronary artery disease (CAD), hypertension (HTN), and use of antihypertensive medications.

Methods: Between January 2003 and June 2004, 27 patients who had aIAB on routine 12‐lead ECGs were identified. Past serial ECGs of each patient were evaluated for evidence of change in IAB type. Medical records of respective patients were then reviewed for HTN, type of antihypertensive medication used, and other common comorbidities.

Results: Median progression time from pIAB to aIAB was shorter (42 months; mean ± SD = 39.2 ± 30.5) compared to that of normal P wave (P‐normal) to aIAB (66 months; mean ± SD = 64.2 ± 25.6). Use of angiotensin‐converting enzyme inhibitors (ACEIs) appeared to significantly delay the progression time in patients who progressed from pIAB to aIAB (50.1 ± 28.3 vs 10 ± 10.4 months; P = 0.04). Beta‐adrenergic blocker use alone did not significantly affect either progression time but when used in conjunction with ACEIs, appeared to slow such progression.

Conclusion: Progression time from pIAB to aIAB is shorter compared to that of P‐normal to aIAB. Given the consequences of IAB, awareness of such progression could be important for clinicians in anticipating potential sequelae.