bluuebunny/crossref_metadata_2025 huggingface dataset:
The Equity Premium: Consistent with GDP Growth and Portfolio Insurance
Authors: Faugère Christophe , Van Erlach Julian
Published: October 2006

We find that the long‐term equity premium is consistent with both GDP growth and portfolio insurance. We use a supply‐side growth model and demonstrate that the arithmetic average stock market return and the returns on corporate assets and debt depend on GDP per capita growth. The implied equity premium matches the U.S. historical average over 1926–2001. Separately, we find that the equity premium tracks the value of a put option on the S&P 500. Our theory predicts a smaller equity premium in the future, assuming that the recent regime shifts in dividend policies, interest rates, and tax rates are permanent.
Verrucous carcinoma of the buccal mucosa: histopathological, cytological and DNA‐cytometric features
Authors: Maraki Dimitra , Boecking Alfred , Pomjanski Natalia , Megahed Mosaad , Becker Juergen
Published: October 2006

We describe a patient with an exophytic oral lesion diagnosed as verrucous carcinoma. The lesion existed without metastases, at least 5 years. Local excisions led to recurrences and continuous expansion. Scalpel biopsies for histopathological and polymerase chain reaction examination were obtained from characteristic regions of the lesion. Brush biopsies for exfoliative cytology (EC) were taken, in order to screen the mucosal area covered by the lesion. After Feulgen restaining of the smears, nuclear DNA contents were measured using a TV image analysis system. An exophytic lesion of the buccal mucosa was diagnosed as low‐grade malignant through histopathology and EC combined with DNA‐image cytometry (peritetraploid DNA‐aneuploidy). Due to almost normal microscopic appearance of the epithelium of verrucous carcinoma, thorough cytological/DNA‐cytometric and histological examinations are needed. Brush biopsies of such neoplastic oral lesions showing DNA‐aneuploidy with peritetraploid stemlines should be used for diagnosis and follow‐up examination of these patients.
Seckel syndrome associated with oligodontia, microdontia, enamel hypoplasia, delayed eruption, and dentin dysmineralization: a new variant?
Authors: De Coster P. J. , Verbeeck R. M. H. , Holthaus V. , Martens L. C. , Vral A.
Published: October 2006

Seckel syndrome (SCKL) [OMIM Entry 210600] is a rare, autosomal recessive syndrome, characterized by severe intrauterine and postnatal growth retardation, microcephaly, mental retardation, and typical facial appearance with beaklike protrusion of the midface (bird‐headed). Associated findings may include limb anomalies, dislocation of femoral heads, scoliosis, and gastrointestinal malformation. A 14‐year‐old boy is presented with brain hypoplasia, pachygyria, hydrocephaly, enamel hypoplasia and root dysplasia in the temporary dentition, and oligodontia, severe microdontia, and delayed eruption of the permanent dentition. The association of SCKL with the above unusual dental findings may represent a new phenotype.
Increased survivin expression in high‐grade oral squamous cell carcinoma: a study in Indian tobacco chewers
Authors: Jane C. , Nerurkar A. V. , Shirsat N. V. , Deshpande R. B. , Amrapurkar A. D. , Karjodkar F. R.
Published: October 2006

Background:  Oral cancer is one of the five leading sites of cancer in the Indian population. In the present study we analyzed the expression of apoptosis regulating genes, viz. survivin, Bcl‐2, Bax and p53 in precancerous and cancerous lesions of the buccal mucosa of Indian tobacco chewers.

Method:  Paraffin‐embedded tissue samples from 38 patients with primary oral squamous cell carcinoma (OSCC) and 17 patients with leukoplakia were used. The expression of survivin, Bcl‐2, Bax, and p53 was evaluated using immunohistochemical staining method.

Results:  Thirty‐six percent OSCC were found to be positive for nuclear p53 staining while none of the precancerous lesions showed p53 positivity. Survivin, Bcl‐2 and Bax expression was found to increase with increased grade of malignancy. Increase in survivin expression was statistically most significant (P < 0.001).

Conclusion:  Increased expression of anti‐apoptotic survivin in high‐grade tumors suggests that survivin is likely to contribute significantly to apoptosis resistance in response to therapy.
Alveolar bone loss in T helper 1/T helper 2 cytokine‐deficient mice
Authors: Alayan J. , Ivanovski S. , Farah C. S.
Published: October 2006

Background and Objective:  The role of cytokines in bone loss is important in the context of periodontitis, where inflammation‐induced bone destruction is a major manifestation. Numerous cytokines have been implicated as mediators of bone resorption. The purpose of this study was to observe the impact of targeted gene deletion of T helper 1 (Th1) and T helper 2 (Th2) cytokines on naturally occurring alveolar bone loss in genetically modified mice.

Material and Methods:  Alveolar bone loss was measured histomorphometrically in interleukin‐4, interleukin‐10, interleukin‐12p40, interferon‐γ (IFN‐γ) and tumor necrosis factor (TNF) knockout mice at 6, 16 and 30 wk of age.

Results:  Both Th1 (interleukin‐12p40, IFN‐γ, TNF) and Th2 (interleukin‐10, interleukin‐4) knockout mice exhibited significantly more alveolar bone loss than their respective wild‐type control mice (p < 0.001). Interleukin‐10–/– and interleukin‐12p40–/– mice exhibited a three‐fold increase in alveolar bone loss at 30 wk of age, whereas bone loss in IFN‐γ–/–, TNF–/– and interleukin‐4–/– mice was 1.5‐ to two‐fold higher compared with wild‐type control mice.

Conclusion:  The results of the present study indicate that both Th1 and Th2 cytokines play an important role in maintaining alveolar bone homeostasis. The kinetics of alveolar bone loss seen in cytokine gene knockout mice indicates that bone loss is age dependent and late in onset.
Melatonin protects against oxidative damage and restores expression of GLUT4 gene in the hyperthyroid rat heart
Authors: Ghosh Goutam , De Kakali , Maity Sangeeta , Bandyopadhyay Debashis , Bhattacharya Samir , Reiter Russel J , Bandyopadhyay Arun
Published: October 2006

Abstract:  To understand the mechanism of cardiovascular dysfunction in the hyperthyroid condition, the role of oxidative stress was examined in rats treated with 3,5,3′‐triiodo‐l‐thyronine (T3). Treatment of rats daily with T3 (8 μg/100 g BW) for 15 days resulted in an increase in heart weight to body weight ratio, which was ameliorated by antioxidants, melatonin (2 mg/100 g BW) or vitamin E (4 mg/100 g BW). Both melatonin and vitamin E also inhibited rises of lipid peroxidation and hydroxyl radical generation and prevented the inhibition of Cu,Zn‐superoxide dismutase in the hypertrophic heart. The expression of the glucose transporter, GLUT4, was reduced in response to T3, which was completely restored by melatonin and partially by vitamin E. However, neither antioxidant prevented down regulation of peroxisome proliferator‐activated receptor‐α in the hyperthyroid heart. Furthermore, the reduced level of myocyte enhancer factor‐2, a regulator of GLUT4 transcription was restored completely by melatonin and partially by vitamin E treatment. Glucose uptake in hypertrophic left ventricular cells was also restored by these antioxidants. The expression of B‐type natriuretic peptide, a marker of heart failure, was significantly increased by T3 and ameliorated by melatonin or vitamin E treatments. In general, the beneficial effects of melatonin given as a co‐treatment with T3 were better than those induced by vitamin E. These data show that melatonin ameliorates hypertrophic growth of the myocardium induced by hyperthyroidism and provide an insight into the mechanism of reactive oxygen species‐mediated down regulation of metabolically important genes such as GLUT4 in the heart.
Leadzyme formed in vivo interferes with tobacco mosaic virus infection in Nicotiana tabacum
Authors: Wyszko Eliza , Nowak Monika , Pospieszny Henryk , Szymanski Maciej , Pas Jakub , Barciszewska Mirosława Z. , Barciszewski Jan
Published: October 2006

We developed a new method for inhibiting tobacco mosaic virus infection in tobacco plants based on specific RNA hydrolysis induced by a leadzyme. We identified a leadzyme substrate target sequence in genomic tobacco mosaic virus RNA and designed a 16‐mer oligoribonucleotide capable of forming a specific leadzyme motif with a five‐nucleotide catalytic loop. The synthetic 16‐mer RNA was applied with nontoxic, catalytic amount of lead to infected tobacco leaves. We observed inhibition of tobacco mosaic virus infection in tobacco leaves in vivo due to specific tobacco mosaic virus RNA cleavage effected by leadzyme. A significant reduction in tobacco mosaic virus accumulation was observed even when the leadzyme was applied up to 2 h after inoculation of leaves with tobacco mosaic virus. This process, called leadzyme interference, is determined by specific recognition and cleavage of the target site by the RNA catalytic strand in the presence of Pb2+.
Human cationic trypsinogen is sulfated on Tyr154
Authors: Sahin‐Tóth Miklós , Kukor Zoltán , Nemoda Zsófia
Published: October 2006

The crystal structure of human pancreatic cationic trypsin showed the chemical modification of Tyr154, which was originally described as phosphorylation [Gaboriaud C, Serre L, Guy‐Crotte O, Forest E & Fontecilla‐Camps JC (1996) J Mol Biol259, 995–1010]. Here we report that Tyr154 is sulfated, not phosphorylated. Cationic and anionic trypsinogens were purified from human pancreatic juice and subjected to alkaline hydrolysis. Modified tyrosine amino acids were separated on a Dowex cation‐exchange column and analyzed by thin layer chromatography. Both human cationic and anionic trypsinogens contained tyrosine sulfate, but no tyrosine phosphate, whereas bovine trypsinogen contained neither. Furthermore, incorporation of [35S]SO4 into human cationic trypsinogen transiently expressed by human embryonic kidney 239T cells was demonstrated. Mutation of Tyr154 to Phe abolished radioactive sulfate incorporation, confirming that Tyr154 is the site of sulfation in cationic trypsinogen. Sulfated pancreatic cationic trypsinogen exhibited faster autoactivation than a nonsulfated recombinant form, suggesting that tyrosine sulfation of trypsinogens might enhance intestinal digestive zymogen activation in humans. Finally, sequence alignment revealed that the sulfation motif is only conserved in primate trypsinogens, suggesting that typsinogen sulfation is absent in other vertebrates.
Influence of Slurry Characteristics on Porosity and Mechanical Properties of Alumina Foams
Authors: Dhara Santanu , Bhargava Parag
Published: October 2006

Alumina foams with porosity ranging between 50% and 92% were fabricated by foaming followed by coagulation of ovalbumin based aqueous slurries. Different combinations of ovalbumin–water mix and alumina loading provided a means to vary slurry viscosity over a wide range. Slurry viscosity influenced the foaming behavior leading to variation in microstructure and mechanical properties of alumina foams. Controlling the slurry viscosity resulted in controlled the total porosity, microstructures and mechanical properties. Mechanical properties were correlated with different micro‐mechanical models. Both microstructure and mechanical properties agreed well as closed cell alumina foam due to presence of low percent area of interconnections.
ECONOMIC IMPACT OF A PROVINCIAL FUEL LEVY: A CGE ANALYSIS
Authors: Mcdonald Scott , Reynolds Sanri , Van Schoor Melt
Published: October 2006

Provincial governments in South Africa, commencing with the Western Cape, are expected to institute provincial fuel levies in addition to the existing national fuel levy in future. This paper presents results from a Computable General Equilibrium (CGE) model calibrated with a detailed Social Accounting Matrix (SAM) to evaluate the effects of a 3 per cent provincial fuel levy implemented simultaneously in all provinces. The results are presented for the petroleum products market, government, the macro economy, industries, factor income (including employment) and household income and expenditure. Results indicate that although the impact of the fuel levy is not drastic, it is large relative to the expected revenue gain. The impact is distributed more uniformly than was expected.
EVALUATING THE GENERAL EQUILIBRIUM EFFECTS OF A WAGE SUBSIDY SCHEME FOR SOUTH AFRICA
Authors: Pauw Kalie , Edwards Lawrence
Published: October 2006

Unemployment among semi‐ and unskilled labour has reached severe proportions (over 50%) and threatens the political and economic stability of the South African economy. In this paper a computable general equilibrium (CGE) model of the South African economy is used to assess the effectiveness of a wage subsidy in raising employment of semi‐ and unskilled workers. We find that employment of semi‐ and unskilled workers can be raised quite significantly. Further, the wage subsidy schemes compares favourably with alternative welfare grant schemes in terms of employment growth. However, the results are sensitive to the targeting of sectors and the substitutability between labour of different skill levels.
THE INTERNATIONAL ADJUSTMENT MECHANISM UNDER RESTRAINT
Authors: Strydom Pdf
Published: October 2006

International imbalances, featuring as large current account deficits and surpluses in different countries are closely related but the adjustment mechanism that should restore equilibrium appears to be under restraint. These imbalances cannot be sustained without severe negative effects on the world economy. The different elements of the adjustment mechanism are complementary and it appears that the current state of economic policy and the absence of incentives to market participants in favour of portfolio switching inhibit an effective adjustment process. Institutional reform in the financial markets of the emerging economies, particularly Asia, appears to be an important prerequisite for the adjustment process to be effective.
THE STRATEGIC USE OF ANTI‐DUMPING IN INTERNATIONAL TRADE
Authors: Bekker Doreen
Published: October 2006

Although anti‐dumping duties are the official countermeasure to the unfair trading practice known as injurious dumping, it is alleged that in some cases anti‐dumping duties are being used to protect certain strategic industries against competitive rather than dumped imports. Although conventional economic wisdom is against such protectionism, some economists argue that certain sensitive and strategic industries may need to be protected against competitive imports even at the cost of economic welfare. This paper argues that more attention should be paid to those strategic industries to establish what is really happening in these industries, while less time and effort should be spent trying to change the Anti‐dumping Agreement.
Habitat selection as a mechanism of resource partitioning in two cryptic bat species Pipistrellus pipistrellus and Pipistrellus pygmaeus
Authors: Nicholls Barry , A. Racey Paul
Published: October 2006

Ecomorphological studies of bat communities often reveal the spatial and temporal coexistence of morphologically similar species, leading to suggestions that these communities are structured by non‐deterministic processes. However, the diversification of echolocation call structure in bats allows for considerable morphological similarity while still permitting niche differentiation based on specialisation for prey type and habitat structure. The recent separation of a common Palaearctic bat, the pipistrelle, into Pipistrellus pipistrellus and P. pygmaeus, which are sympatrically distributed throughout their range, raises the question as to whether these two morphologically similar species partition resources in time and space.

To test the hypothesis that the coexistence of these cryptic species is facilitated by differential habitat use, 14 P. pipistrellus, and 12 P. pygmaeus were radio‐tracked from adjacent maternity roosts, in northeast Scotland, from May to September 2002/2003. The two species showed distinct habitat partitioning with P. pygmaeus foraging predominantly in riparian woodland and over water, and P. pipistrellus foraging along woodland edges and short isolated tree lines. Inter‐specific overlap in habitat use was low and consequently foraging ranges were segregated spatially.

The degree of habitat partitioning revealed in these species, which show considerable overlap in echolocation call parameters and functional morphology, suggests that morphological features, whilst useful in separating chiropteran species into coarse‐grained foraging guilds, may not predict fine‐grained ecological segregation.
Effect of masker type and age on speech intelligibility and spatial release from masking in children and adults
Authors: Johnstone Patti M. , Litovsky Ruth Y.
Published: October 2006

Speech recognition in noisy environments improves when the speech signal is spatially separated from the interfering sound. This effect, known as spatial release from masking (SRM), was recently shown in young children. The present study compared SRM in children of ages 5–7 with adults for interferers introducing energetic, informational, and/or linguistic components. Three types of interferers were used: speech, reversed speech, and modulated white noise. Two female voices with different long-term spectra were also used. Speech reception thresholds (SRTs) were compared for: Quiet (target 0° front, no interferer), Front (target and interferer both 0° front), and Right (interferer 90° right, target 0° front). Children had higher SRTs and greater masking than adults. When spatial cues were not available, adults, but not children, were able to use differences in interferer type to separate the target from the interferer. Both children and adults showed SRM. Children, unlike adults, demonstrated large amounts of SRM for a time-reversed speech interferer. In conclusion, masking and SRM vary with the type of interfering sound, and this variation interacts with age; SRM may not depend on the spectral peculiarities of a particular type of voice when the target speech and interfering speech are different sex talkers.
Acoustic detection of North Atlantic right whale contact calls using the generalized likelihood ratio test
Authors: Urazghildiiev Ildar R. , Clark Christopher W.
Published: October 2006

This paper addresses the problem of passive acoustic detection of contact calls produced by the highly endangered North Atlantic right whale Eubalaena glacialis. The proposed solution is based on using a generalized likelihood ratio test detector of polynomial-phase signals with unknown amplitude and polynomial coefficients observed in the presence of locally stationary Gaussian noise. The closed form representation for a minimal sufficient statistic is derived and a realizable detection scheme is developed. The receiver operation characteristic curves are calculated using empirical data recordings containing known right whale calls. The curves demonstrate that the proposed detector provides superior detection performance as compared with other known detection techniques for northern right whale contact calls.
The use of microperforated plates to attenuate cavity resonances
Authors: Fenech Benjamin , Keith Graeme M. , Jacobsen Finn
Published: October 2006

The use of microperforated plates to introduce damping in a closed cavity is examined. By placing a microperforated plate well inside the cavity instead of near a wall as traditionally done in room acoustics, high attenuation can be obtained for specific acoustic modes, compared with the lower attenuation that can be obtained in a broad frequency range with the conventional position of the plate. An analytical method for predicting the attenuation is presented. The method involves finding complex eigenvalues and eigenfunctions for the modified cavity and makes it possible to predict Green’s functions. The results, which are validated experimentally, show that a microperforated plate can provide substantial attenuation of modes in a cavity. One possible application of these findings is the treatment of boiler tones in heat-exchanger cavities.
Hybrid feedforward-feedback active noise reduction for hearing protection and communication
Authors: Ray Laura R. , Solbeck Jason A. , Streeter Alexander D. , Collier Robert D.
Published: October 2006

A hybrid active noise reduction (ANR) architecture is presented and validated for a circumaural earcup and a communication earplug. The hybrid system combines source-independent feedback ANR with a Lyapunov-tuned leaky LMS filter (LyLMS) improving gain stability margins over feedforward ANR alone. In flat plate testing, the earcup demonstrates an overall C-weighted total noise reduction of 40dB and 30–32dB, respectively, for 50–800Hz sum-of-tones noise and for aircraft or helicopter cockpit noise, improving low frequency (<100Hz) performance by up to 15dB over either control component acting individually. For the earplug, a filtered-X implementation of the LyLMS accommodates its nonconstant cancellation path gain. A fast time-domain identification method provides a high-fidelity, computationally efficient, infinite impulse response cancellation path model, which is used for both the filtered-X implementation and communication feedthrough. Insertion loss measurements made with a manikin show overall C-weighted total noise reduction provided by the ANR earplug of 46–48dB for sum-of-tones 80–2000Hz and 40–41dB from 63to3000Hz for UH-60 helicopter noise, with negligible degradation in attenuation during speech communication. For both hearing protectors, a stability metric improves by a factor of 2 to several orders of magnitude through hybrid ANR.
On the modeling of sound radiation from poroelastic materials
Authors: Atalla Noureddine , Sgard Franck , Amedin Celse Kafui
Published: October 2006

Numerical approaches based on finite element discretizations of Biot’s poroelasticity equations provide efficient tools to solve problems where the porous material is coupled to elastic structures and finite extent acoustic cavities. Sometimes, it may be relevant to evaluate the radiation of a poroelastic material into an infinite fluid medium. Examples include (i) the evaluation of the diffuse field sound absorption coefficient of a porous material and/or the sound transmission loss of an elastic plate coupled to a porous sheet, (ii) the assessment of the acoustic radiation damping of a porous material coupled to a vibrating structure. The latter is particularly important for the correct experimental characterization of the intrinsic damping of the material’s frame. Up to now, the acoustic radiation of a porous medium into an unbounded fluid medium has usually been neglected. The classical approaches for modeling free field radiation of porous materials (i) assumes the interstitial pressure at the radiation surface to be zero or (ii) fixes the radiation impedance to an approximate value. This paper discusses the limitations of these assumptions and presents a numerical formulation for evaluating the sound radiation of baffled poroelastic media including fluid loading effects. The problem is solved using a mixed FEM-BEM approach where the fluid loading is accounted for using an admittance matrix. Both numerical examples and a transmission loss test are presented to illustrate the performance of the technique and its applications.
Validation of statistical estimation of transmission loss in the presence of geoacoustic inversion uncertainty
Authors: Huang Chen-Fen , Gerstoft Peter , Hodgkiss William S.
Published: October 2006

Often the ocean acoustic environment is not well known and sonar performance prediction will be affected by this uncertainty. Here, a method for estimating transmission loss (TL) is proposed which incorporates these environmental uncertainties. Specifically, we derive an approach for the statistical estimation of TL based on the posterior probability density of environmental parameters obtained from the geoacoustic inversion process. First, a Markov chain Monte Carlo procedure is employed in the inversion process to sample the posterior probability density of the geoacoustic parameters. Then, these sampled parameters are mapped to the transmission loss domain where a full multidimensional probability distribution of TL as a function of range and depth is obtained. In addition, TL is also characterized by its summary statistics including the median, percentiles, and correlation coefficients. The approach is illustrated using a data set obtained from the ASIAEX 2001 East China Sea experiment. Based on the geoacoustic inversion results, the predicted TL and its variability are estimated and then compared with the measured TL. In general, there is a good agreement with the percentage of observed number of data points inside the credibility interval.
The relationship between railway noise and community annoyance in Korea
Authors: Lim Changwoo , Kim Jaehwan , Hong Jiyoung , Lee Soogab
Published: October 2006

A study of community annoyance caused by exposures to railway noise was carried out in 18 areas along railway lines to accumulate social survey data and assess the relationship between railway noise levels and annoyance responses in Korea. Railway noise levels were measured with portable sound-level meters. Social surveys were administered to people living within 50m of noise measurement sites. A questionnaire contained demographic factors, degree of noise annoyance, interference with daily activities, and health-related symptoms. The question relating to noise annoyance was answered on an 11-point numerical scale. The randomly selected respondents, who were aged between 18 to 70 years of age, completed the questionnaire independently. In total, 726 respondents participated in social surveys. Taking into consideration the urban structure and layout of the residential areas of Korea, Japan, and Europe, one can assume that the annoyance responses caused by the railway noise in this study will be similar to those found in Japan, which are considerably more severe than those found in European countries. This study showed that one of the most important factors contributing to the difference in the annoyance responses between Korea and Europe is the distance between railways and houses.
Jet offset, harmonic content, and warble in the flute
Authors: Coltman John W.
Published: October 2006

The effects of jet offset in the flute, directing the jet above or below the edge, were explored by two distinct means—experiments with a Boehm flute sounded by an artificial blower, and time domain simulation. Very large changes in harmonic content and dynamics were observed, changing greatly with blowing pressure. Warble, a modulation of the tone at frequencies of the order of 20Hz, was observed both in the experiment and in the simulation. The phenomenon is explained as a beat between the frequency of a second harmonic generated by nonlinearity in the jet current and a neighboring partial sustained by jet feedback near the second mode resonance. A second type of warble, in which amplitude modulation occurs in all partials but with different phases, is yet to be explained.
Ultrasonic characterization of human cancellous bone using the Biot theory: Inverse problem
Authors: Sebaa N. , Fellah Z. E. A. , Fellah M. , Ogam E. , Wirgin A. , Mitri F. G. , Depollier C. , Lauriks W.
Published: October 2006

This paper concerns the ultrasonic characterization of human cancellous bone samples by solving the inverse problem using experimental transmitted signals. The ultrasonic propagation in cancellous bone is modeled using the Biot theory modified by the Johnson et al. model for viscous exchange between fluid and structure. The sensitivity of the Young modulus and the Poisson ratio of the skeletal frame is studied showing their effect on the fast and slow wave forms. The inverse problem is solved numerically by the least squares method. Five parameters are inverted: the porosity, tortuosity, viscous characteristic length, Young modulus, and Poisson ratio of the skeletal frame. The minimization of the discrepancy between experiment and theory is made in the time domain. The inverse problem is shown to be well posed, and its solution to be unique. Experimental results for slow and fast waves transmitted through human cancellous bone samples are given and compared with theoretical predictions.
A forward model and conjugate gradient inversion technique for low-frequency ultrasonic imaging
Authors: van Dongen Koen W. A. , Wright William M. D.
Published: October 2006

Emerging methods of hyperthermia cancer treatment require noninvasive temperature monitoring, and ultrasonic techniques show promise in this regard. Various tomographic algorithms are available that reconstruct sound speed or contrast profiles, which can be related to temperature distribution. The requirement of a high enough frequency for adequate spatial resolution and a low enough frequency for adequate tissue penetration is a difficult compromise. In this study, the feasibility of using low frequency ultrasound for imaging and temperature monitoring was investigated. The transient probing wave field had a bandwidth spanning the frequency range 2.5–320.5kHz. The results from a forward model which computed the propagation and scattering of low-frequency acoustic pressure and velocity wave fields were used to compare three imaging methods formulated within the Born approximation, representing two main types of reconstruction. The first uses Fourier techniques to reconstruct sound-speed profiles from projection or Radon data based on optical ray theory, seen as an asymptotical limit for comparison. The second uses backpropagation and conjugate gradient inversion methods based on acoustical wave theory. The results show that the accuracy in localization was 2.5mm or better when using low frequencies and the conjugate gradient inversion scheme, which could be used for temperature monitoring.
Volumetric acoustic vector intensity imager
Authors: Williams Earl G. , Valdivia Nicolas , Herdic Peter C. , Klos Jacob
Published: October 2006

A new measurement system, consisting of a mobile array of 50 microphones that form a spherical surface of radius 0.2m, that images the acoustic intensity vector throughout a large volume is discussed. A simultaneous measurement of the pressure field across all the microphones provides time-domain holograms. Spherical harmonic expansions are used to convert the measured pressure into a volumetric vector intensity field on a grid of points ranging from the origin to a maximum radius of 0.4m. Displays of the volumetric intensity image are used to locate noise sources outside the volume. There is no restriction on the type of noise source that can be studied. An experiment inside a Boeing 757 aircraft in flight successfully tested the ability of the array to locate flow-noise-excited sources on the fuselage. Reference transducers located on suspected noise source locations can also be used to increase the ability of this device to separate and identify multiple noise sources at a given frequency by using the theory of partial field decompositions. The frequency range of operation is 0to1400Hz. This device is ideal for the diagnostic analysis of noise sources in commercial and military transportation vehicles in air, on land, and underwater.
Constrained comparison of ocean waveguide reverberation theory and observations
Authors: Holland Charles W.
Published: October 2006

Measurements of long-range (order 104m) shallow-water reverberation in the Straits of Sicily at 900 and 1800Hz are compared with theoretical predictions. All of the required environmental inputs for the theory are obtained independently, that is to say there are no free parameters. The reflection coefficient and the scattering strength are measured by direct path methods; both quantities show strong frequency dependence. The theoretical reverberation predictions using these measurements are in good agreement with directional reverberation data, i.e., within the expected uncertainty bounds. The good agreement suggests that the supporting environmental measurement techniques are robust and that the physics associated with reverberation in a waveguide is reasonably well understood, at least in simple environments. The ability to independently measure the seabed scattering strength and reflection coefficient is a crucial step for the advancement of inverse methods using reverberation (e.g., rapid environmental assessment) inasmuch as it provides the means for quantitatively measuring the robustness of those methods.
A Putative Ariadne-Like Ubiquitin Ligase Is Required for
Dictyostelium discoideum
Development
Authors: Whitney Nathaniel , Pearson Lacey J. , Lunsford Ryan , McGill Lisa , Gomer Richard H. , Lindsey David F.
Published: October 2006

The
Dictyostelium rbrA
gene encodes a putative Ariadne ubiquitin ligase.
rbrA

−

cells form defective slugs that cannot phototax. Prestalk cell numbers are reduced in
rbrA

−

slugs, and these prestalk cells do not localize to the tip of slugs. Chimeric slugs containing wild-type cells could phototax and form fruiting bodies.
SWI/SNF Displaces SAGA-Acetylated Nucleosomes
Authors: Chandy Mark , Gutiérrez José L. , Prochasson Philippe , Workman Jerry L.
Published: October 2006

SWI/SNF is a well-characterized chromatin remodeling complex that remodels
chromatin by sliding nucleosomes in
cis
and/or displacing
nucleosomes in
trans
. The latter mechanism has the potential
to remove promoter nucleosomes, allowing access to transcription
factors and RNA polymerase. In vivo, histone acetylation often precedes
apparent nucleosome loss; therefore, we sought to determine whether
nucleosomes containing acetylated histones could be displaced by the
SWI/SNF chromatin remodeling complex. We found that SAGA-acetylated
histones were lost from an immobilized nucleosome array when treated
with the SWI/SNF complex. When the nucleosome array was acetylated by
SAGA in the presence of bound transcription activators, it generated a
peak of acetylation surrounding the activator binding sites. Subsequent
SWI/SNF treatment suppressed this acetylation peak. Immunoblots
indicated that SWI/SNF preferentially displaced acetylated histones
from the array relative to total histones. Moreover, the Swi2/Snf2
bromodomain, an acetyl-lysine binding domain, played a role in the
displacement of acetylated histones. These data indicate that targeted
histone acetylation by the SAGA complex predisposes promoter
nucleosomes for displacement by the SWI/SNF
complex.
A Glucose Sensor in
Candida albicans
Authors: Brown Victoria , Sexton Jessica A. , Johnston Mark
Published: October 2006

The Hgt4 protein of
Candida albicans
(orf19.5962) is orthologous to the Snf3 and Rgt2 glucose sensors of
Saccharomyces cerevisiae
that govern sugar acquisition by regulating the expression of genes encoding hexose transporters. We found that
HGT4
is required for glucose induction of the expression of
HGT12
,
HXT10
, and
HGT7
, which encode apparent hexose transporters in
C. albicans
. An
hgt4Δ
mutant is defective for growth on fermentable sugars, which is consistent with the idea that Hgt4 is a sensor of glucose and similar sugars. Hgt4 appears to be sensitive to glucose levels similar to those in human serum (∼5 mM).
HGT4
expression is repressed by high levels of glucose, which is consistent with the idea that it encodes a high-affinity sugar sensor. Glucose sensing through Hgt4 affects the yeast-to-hyphal morphological switch of
C. albicans
cells:
hgt4Δ
mutants are hypofilamented, and a constitutively signaling form of Hgt4 confers hyperfilamentation of cells. The
hgt4Δ
mutant is less virulent than wild-type cells in a mouse model of disseminated candidiasis. These results suggest that Hgt4 is a high-affinity glucose sensor that contributes to the virulence of
C. albicans
.
Mitogen-Activated Protein Kinase Hog1 Is Essential for the Response to Arsenite in
Saccharomyces cerevisiae
Authors: Sotelo Jael , Rodríguez-Gabriel Miguel A.
Published: October 2006

Here we describe, for the first time, that budding yeast mitogen-activated protein kinase Hog1 and its upstream activators Pbs2 and Ssk1 are essential for the response to arsenite. Hog1 is rapidly phosphorylated in response to arsenite and triggers a transcriptional response that involves the upregulation of genes essential for arsenite detoxification.
Interaction of complement and leukocytes in severe acute pancreatitis: potential for therapeutic intervention
Authors: Hartwig Werner , Klafs Martina , Kirschfink Michael , Hackert Thilo , Schneider Lutz , Gebhard Martha-Maria , Büchler Markus W. , Werner Jens
Published: October 2006

In acute pancreatitis, local as well as systemic organ complications are mediated by the activation of various inflammatory cascades. The role of complement in this setting is unclear. The aim of the present study was to determine the level of complement activation in experimental pancreatitis, to evaluate the interaction of complement and leukocyte-endothelium activation, and to assess the effects of complement inhibition by soluble complement receptor 1 (sCR1) in this setting. Necrotizing pancreatitis was induced in Wistar rats by the combination of intravenous cerulein and retrograde infusion of glycodeoxycholic acid into the biliopancreatic duct; edematous pancreatitis was induced by intravenous cerulein only. In control animals, a sham operation (midline laparotomy) was performed. Complement activation, leukocyte sequestration, and pancreatic as well as pulmonary injury were assessed in the presence/absence of sCR1. Increased levels of C3a were found in necrotizing but not in edematous pancreatitis. When complement activation in necrotizing pancreatitis was blocked by sCR1, levels of C3a and total hemolytic activity (CH50) were decreased. Leukocyte-endothelial interaction, as assessed by intravital microscopy, and pancreatic as well as pulmonary organ injury (wet-to-dry weight ratio, MPO activity, and histology) were ameliorated by sCR1. As a result of the present study, necrotizing but not edematous pancreatitis is characterized by significant and early complement activation. Based on the interaction of complement and leukocytes, complement inhibition by sCR1 may be a valuable option in the treatment of leukocyte-associated organ injury in severe pancreatitis.
Phospholipase D and extracellular signal-regulated kinase in hepatic stellate cells: effects of platelet-derived growth factor and extracellular nucleotides
Authors: Benitez-Rajal Joaquin , Lorite Maria-Jose , Burt Alastair D. , Day Christopher P. , Thompson Michael G.
Published: October 2006

We have previously provided evidence suggesting that phosphatidic acid, possibly derived from the hydrolysis of phosphatidylcholine by phospholipase D (PLD), is involved in platelet-derived growth factor (PDGF)-mediated increases in extracellular signal-regulated kinase (ERK) activity and DNA synthesis in rat hepatic stellate cells (HSC), the primary fibrogenic cells of the liver. A recent study has shown the presence of P2Y nucleotide receptors on HSC that are coupled to contraction and synthesis of the matrix component, α1-procollagen, leading to the suggestion that they may represent a new therapeutic target in the treatment of liver fibrosis. However, although extracellular nucleotides have been shown to stimulate both PLD and ERK, and to elicit proliferation of fibrogenic cells outside the liver, their effect on these parameters in HSC have not yet been investigated. PLD activity was determined by [3H]choline release and [3H]phosphatidylbutanol production, ERK activity by Western blotting, and DNA synthesis by [3H]thymidine incorporation. We report here, for the first time in HSC, that extracellular nucleotides stimulate PLD activity and a sustained activation of ERK. However, in contrast to PDGF, nucleotides had negligible effects on DNA synthesis. Moreover, the effects of PDGF and nucleotides on PLD and ERK were not additive, suggesting activation of the same PLD isoform and pool of ERK. The data demonstrate that nucleotide-stimulated PLD and ERK activities are not coupled to DNA synthesis in HSC. Instead, these responses may be linked to other phenotypic changes associated with activated HSC such as increases in contraction, motility, or extracellular matrix deposition.
IL-10 protects mouse intestinal epithelial cells from Fas-induced apoptosis via modulating Fas expression and altering caspase-8 and FLIP expression
Authors: Bharhani Mantej S. , Borojevic Rajka , Basak Shibesh , Ho Edwin , Zhou Pengfei , Croitoru Kenneth
Published: October 2006

We have previously shown that the absence of Fas/Fas ligand significantly reduced tissue damage and intestinal epithelial cell (IEC) apoptosis in an in vivo model of T cell-mediated enteropathy. This enteropathy was more severe in IL-10-deficient mice, and this was associated with increased serum levels of IFN-γ and TNF-α and an increase in Fas expression on IECs. In this study, we investigated the potential of IL-10 to directly influence Fas expression and Fas-induced IEC apoptosis. Mouse intestinal epithelial cell lines MODE-K and IEC4.1 were cultured with IFN-γ, TNF-α, or anti-Fas monoclonal antibody (mAb) in the presence or absence of IL-10. Fas expression and apoptosis were determined by FACScan analysis of phycoerythrin-anti-Fas mAb staining and annexin V staining, respectively. Treatment with a combination of IFN-γ and TNF-α induced significant apoptosis. Anti-Fas mAb alone did not induce much apoptosis unless cells were pretreated with IFN-γ and TNF-α. These IECs constitutively expressed low levels of Fas, which significantly increased by preincubation of the cells with IFN-γ and TNF-α. Treatment with cytokine or cytokine plus anti-Fas mAb increased apoptosis, which correlated with a decreased Fas-associated death domain IL-1-converting enzyme-like inhibitory protein (FLIP) level, increased caspase-8 activity, and subsequently increased caspase-3 activity. IL-10 diminished both cytokine- and anti-Fas mAb-induced apoptosis, and this was correlated with decreased cytokine-induced Fas expression, increased FLIP, and decreased caspase-8 and caspase-3 activity. In conclusion, IL-10 modulated cytokine induction of Fas expression on IEC cell lines and regulated IEC susceptibility to TNF-α, IFN-γ, and Fas-mediated apoptosis. These findings suggest that IL-10 directly modulates IEC responses to T cell-mediated apoptotic signals.
Effect of marigold (Tagetes patula) on population dynamics of Pratylenchus penetrans in a field
Authors: Pudasaini Mahesh , Viaene Nicole , Moens Maurice
Published: October 2006

The effect of a sequence of host and non-host crops on the population dynamics of Pratylenchus penetrans was monitored for 2 years in a field. The sequence was pea (Pisum sativum, 25% cv. Colombia and 75% cv. Coca), French marigolds (Tagetes patula nana cv. Sparky); fallow; carrot (Daucus carota, cv. Amsterdamse bak); bean (Phaseolus vulgaris, cv. Avignon) and again fallow. Samples were taken every 21 days during the marigold crop and following fallow, and at planting and harvest for the other crops. From five 2 × 5 m2 plots, 15 cores were taken per plot to a depth of 70 cm and split into seven segments of 10 cm each. Within the plots, segments from corresponding depths were pooled and nematodes were estimated from a 200 g subsample. Densities of P. penetrans increased 2.2-fold under pea, but decreased by 90% after marigolds had been grown for 105 days. The P. penetrans population was reduced by about 90% in the soil layer above 40 cm while the reduction was about 80% below 50 cm after 105 days of marigold culture. Densities of P. penetrans declined exponentially in time under marigold and fallow. The effect of marigold was persistent as no increase in P. penetrans densities over the whole soil profile was noticed after two crop cycles of host plants.
Dinetia decraemerae n. sp. (Nematoda: Draconematidae), a new free-living marine nematode from a subtidal zone in Korea
Authors: Paik Sang-Gyu , Rho Hyun Soo , Kim Won
Published: October 2006

Dinetia decraemerae n. sp., a new species of the family Draconematidae, is described. This new species was collected from subtidal coarse sediments and small logs from the eastern coast of Korea. Dinetia decraemerae n. sp. is distinguished from D. nycterobia and D. orientalis by the following combination of characters: number of cephalic adhesion tubes (34-36 in male and 32-34 in female), number of sublateral posterior adhesion tubes (7-8 in male and 12-13 in female) and subventral posterior adhesion tubes (16-20 in male and 17-19 in female), the buccal cavity (narrow and armed with a dorsal and two minute ventrosublateral teeth), the body striation (not completely surrounding the unispiral amphidial fovea), large, slightly curved, spicules, gubernacular apparatus paired with distal lateral enlargement of the corpus extending around distal part of each spicule, and C′ value (2.6-2.9 in male and 3.4-3.8 in female). The generic diagnosis is emended and a key to species provided.
Moss inhabiting nematodes: influence of the moss substratum and geographical distribution in Europe
Authors: Zullini Aldo , Barbuto Michela
Published: October 2006

The impact of the moss substratum (soil or rock) on the species composition of nematode assemblages was investigated. Samples of different species of moss were collected at several stations in Italy. Nematode density was very variable between samples and substrata, but nematode assemblages were very similar in trophic group structure and diversity. Predator dominance and the high percentage of Dorylaimida indicate the good quality of the investigated stations. Species richness and biomass were higher in mosses growing on soil where large nematodes such as Aporcelaimellus obtusicaudatus were abundant. No clear substratum-dependent species pattern was found: only Tripylella intermedia appears to be exclusive for mosses growing on rocks. Prionchulus muscorum and Plectus acuminatus were the commonest species and occurred in almost all samples. By comparing our moss communities with those of other European communities reported in the literature, we detected significant differences between continental and Mediterranean communities.
The role of conscientiousness and extraversion in affecting the relationship between perceptions of group potency and volunteer group member selling behavior: An interactionist perspective
Authors: Neubert Mitchell , Taggar Simon , Cady Steven
Published: October 2006

We studied 284 volunteers, loosely coupled in groups (i.e. low task interdependence, high outcome interdependence), selling memberships in a non-profit organization. Consistent with economic models of altruism, we found individual perceptions of group potency to be negatively related to individual selling behavior (i.e. making telephone calls and customer visits). Furthermore, individual members’ perceptions of group potency were found to interact with two personality traits (conscientiousness and extraversion) to influence individual selling behavior.
Gender as multiplicity: Desire, displacement, difference and dispersion
Authors: Linstead Stephen , Pullen Alison
Published: October 2006

This article argues that although gender is no longer widely considered to be a property of individuals, the alternative of viewing it in terms of performativity, where it is the outcome of linguistic and social performances, unnecessarily limits the possibilities of thinking of gender as a form of multiplicity that is both internally and externally differentiated. Any attempt to move beyond binary thinking in gender relations initiates a consideration of multiplicity, and the way in which multiplicity is conceptualized exerts a critical influence on the possibilities that are opened up. This article interrogates existing understandings of multiplicity and finds three actual or possible types - multiplicities of the same, characteristic of feminist approaches which we critique through a reconceptualization of desire; multiplicities of the third, characterized by anthropological, transgender and queer theory approaches; and multiplicities of difference and dispersion, typified by the rhizomatics and fluid theorizing of Deleuze and Guattari, Grosz and Olkowski. We propose an ontology of gender as a creative and productive form of desire, realized as proliferation in Deleuze and Guattari’s model of the rhizome. Gender identity is accordingly rethought as immanence, intensity and consistency.