bluuebunny/crossref_metadata_2025 huggingface dataset:
An extended advancing front technique for closed surfaces mesh generation
Authors: Guan Zhenqun , Shan Julin , Zheng Yao , Gu Yuanxian
Published: September 2007

An extended advancing front technique (AFT) with shift operations and Riemann metric named as shifting‐AFT is presented for finite element mesh generation on 3D surfaces, especially 3D closed surfaces. Riemann metric is used to govern the size and shape of the triangles in the parametric space. The shift operators are employed to insert a floating space between real space and parametric space during the 2D parametric space mesh generation. In the previous work of closed surface mesh generation, the virtual boundaries are adopted when mapping the closed surfaces into 2D open parametric domains. However, it may cause the mesh quality‐worsening problem. In order to overcome this problem, the AFT kernel is combined with the shift operator in this paper. The shifting‐AFT can generate high‐quality meshes and guarantee convergence in both open and closed surfaces. For the shifting‐AFT, it is not necessary to introduce virtual boundaries while meshing a closed surface; hence, the boundary discretization procedure is largely simplified, and moreover, better‐shaped triangles will be generated because there are no additional interior constraints yielded by virtual boundaries. Comparing with direct methods, the shifting‐AFT avoids costly and unstable 3D geometrical computations in the real space. Some examples presented in this paper have demonstrated the advantages of shift‐AFT in 3D surface mesh generation, especially for the closed surfaces. Copyright © 2007 John Wiley & Sons, Ltd.
Preparation and properties of benzophenone chromophoric group branched polymer for self‐decontamination
Authors: Hong Kyung Hwa , Sun Gang
Published: September 2007

To prepare self‐decontamination materials with highly reactive chemical species, such as radicals, the benzophenone chromophoric group branched polymer was synthesized by Friedel–Crafts acylation of polystyrene with benzoyl chloride. The resultant polymer could be prepared into a casting film, and the polymer solution and film were characterized by FTIR, NMR, UV–VIS, XRD, and DSC. From the analyses, it was verified that the benzophenone chromophoric group branched polymer was successfully prepared, and the resultant polymer revealed radical reactivities such as antibacterial effect and decoloration of dye, under UV irradiation. POLYM. ENG. SCI., 47:1750–1755, 2007. © 2007 Society of Plastics Engineers
Photoinitiated crosslinking of ethylene‐vinyl acetate copolymers and characterization of related properties
Authors: Yao Dahong , Qu Baojun , Wu Qianghua
Published: September 2007

Photoinitiated crosslinking of EVA in the presence of benzophenone (BP) as photoinitiator and triallyl isocyanurate (TAIC) as crosslinker and characterization of the related properties have been studied by gel determination, heat extension, DSC, DMTA, TGA, and mechanical measurements. The photoinitiated crosslinking efficiency of the EVA‐BP‐TAIC system and various factors affecting the crosslinking process, such as photoinitiator and crosslinker and their concentrations, irradiation temperature, and irradiation atmosphere were studied in detail and optimized by comparison of gel contents. The results show that the EVA samples with a thickness of 1 mm are readily crosslinked to a gel content of above 80% with 5 s UV‐irradiation under optimum conditions. The data from the heat extension and DSC show that the crosslinking density of photocrosslinked EVA increase and their crystallinities decrease with increasing the UV‐irradiation time. At the same time, photocrosslinking of EVA leads to a lowering of the melt temperature and a decrease of heat of fusion. The DMTA results show that photocrosslinking increases the amorphous phase and storage modulus of the crosslinked EVA, but does not change the glass transition temperature. The data from TGA and mechanical tests give evidence that the thermal stability and mechanical properties of photocrosslinked EVA samples are much better than those of the uncrosslinked EVA. POLYM. ENG. SCI., 47:1761–1767, 2007. © 2007 Society of Plastics Engineers
Dynamic viscoelastic properties of fluoroelastomer/clay nanocomposites
Authors: Maiti Madhuchhanda , Bhowmick Anil K.
Published: September 2007

Nanocomposites based on fluoroelastomer and modified and unmodified sodium montmorillonite clays were prepared. Dynamic mechanical thermal analysis was performed on these nanocomposites over a range of temperatures (−60 to +60°C), frequencies (0.032–32 Hz), and strains (0.002%–2%). The results showed that there were significant changes in the glass transition temperature and storage modulus with the addition of small amount (4 phr) of the modified and the unmodified nanofillers. The tan δ peak heights decreased and the storage modulus increased in general, but it was more prominent in the case of the unmodified clay. With the addition of the nanoclays, the cross‐over point in the double logarithmic plot of storage modulus (E′) and complex viscosity (η*) with frequency, shifted toward higher frequency. Interestingly, with increasing strain, the nanocomposites demonstrated a sudden upturn in the storage modulus after ∼0.2% strain amplitude, because of the formation of α‐crystallization in the elastomer structure. The uniaxial strain before strain sweep experiment increased the storage modulus remarkably. The results were explained with the help of X‐ray diffraction and transmission electron microscopy. POLYM. ENG. SCI., 47:1777–1787, 2007. © 2007 Society of Plastics Engineers
Thermal and mechanical degradation during polymer extrusion processing
Authors: Capone C. , Di Landro L. , Inzoli F. , Penco M. , Sartore L.
Published: September 2007

Polymer processing often activates material degradation, which affects to some extent the performance or the life cycle of the obtained products. Polymer degradation is usually evidenced by molecular weight variations as consequence of exposure to high processing temperature and to relevant mechanical stresses. The degrading effects of melt extrusion under different thermo‐mechanical conditions on polymethyl‐methacrylate and polystyrene are investigated. Materials were processed at different temperatures and rates in a single screw extruder and in a capillary rheometer. Processed and as‐received materials were analysed by Gel permeation chromatography, solution viscosity, and melt rheology. Evaluations of molecular weight and rheological behavior changes after processing, as compared with as‐received materials, evidenced the extent of degradation in the different conditions. Experimental analysis was accompanied by finite elements simulation of the polymer flow and heat transmission within the extruder. This allowed an estimation of the expected shear stresses and temperatures distributions, thus indicating potentially critical situations. It was found that the materials processed at the highest rates in extruder presented lowest molecular weight reductions. This was attributed to the shorter residence time in the extruder and to the possibility of wall slip phenomena, which likely reduce the actual shear stress and viscous dissipation in the fast processing conditions. POLYM. ENG. SCI., 47:1813–1819, 2007. © 2007 Society of Plastics Engineers
Controllable fabrication and properties of polypropylene nanofibers
Authors: Wang Dong , Sun Gang , Chiou Bor‐Sen , Hinestroza Juan P.
Published: September 2007

Thermoplastic nanofibers in yarn form were prepared by melt extrusion of immiscible blends of cellulose acetate butyrate (CAB) and thermoplastic polymers and subsequent removal of the CAB matrix. Isotactic polypropylene (iPP) nanofiber, with diameters ranging from 75 to 375 nm, were made by using CAB/iPP blends, with a ratio of 97.5–2.5, and a hot‐drawn ratio of 25 in a twin‐screw extruder. Dispersion of iPP in CAB and shear and elongational deformation are major factors to result in nanosized fibers. The spheres and nanofibers with different diameters of iPP dispersed phases in the CAB matrix can be well controlled by changing the flow field and the blend ratio. Differential scanning calorimeter and wide angle X‐ray diffraction results showed that the nanofibers had lower crystallinity and crystallite thickness compared with bulk iPP. The atomic force microscopy images presented the well‐defined nanofiber morphology and the excellent manipulability of single iPP nanofiber separated from a bundle of iPP nanofibers. POLYM. ENG. SCI., 47:1865–1872, 2007. © 2007 Society of Plastics Engineers
Development of freeze flow apparatus to study filled polymer melts
Authors: Beard M.A. , Tabor G.R. , Ritchie S.J.K. , Evans K.E. , Walton R.I.
Published: September 2007

A novel method to study the distribution of filler particles and polymer orientation of a polymer melt within a capillary die has been developed. Material within the die is quench‐cooled and then removed to provide information about the flow regime at the instant it was frozen. The equipment has been used to examine calcium carbonate‐filled high density polyethylene under high shear. The samples were examined using Energy Dispersive X‐ray Spectrometry (EDS) as well as being studied using X‐ray Diffraction (XRD). The distribution of filler particles across the radius of the capillary has been studied at high and low wall shear rates using EDS. A constant particle distribution across the radius of the die was observed for both flow regimes. The arrangement of crystalline structures within the specimens was examined by XRD. An increase in crystalline order was noticed with increasing wall shear rate. POLYM. ENG. SCI., 47:1937–1942, 2007. © 2007 Society of Plastics Engineers
High‐Tc cuprate superconductivity as a new paradigm
Authors: Won Hyekyung , Morita Yoshifumi , Maki Kazumi
Published: September 2007

High‐Tc cuprate superconductivity was discovered two decades ago by Bednorz and Müller. Even now the origin and the nature of this remarkable group of superconductors appear to be hotly debated in the literature. However, we believe that a few things are clearly established: (i) the high‐Tc cuprate superconductors in the overdoped region are the BCS d‐wave superconductors (dSC), (ii) the pseudogap phase is a d‐wave spin density wave (dSDW) and (iii) the superconductivity in the underdoped region is gossamer (i.e. dSC in coexistence with dSDW). Here we review these developments and consider a class of nodal superconductors, which share similar phase diagrams to those for high‐Tc cuprate superconductors. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pressure‐induced phenomena in single‐walled carbon nanotubes
Authors: Kuntscher C. A. , Thirunavukkuarasu K. , Pekker Á. , Kamarás K. , Hennrich F. , Kappes M. , Iwasa Y.
Published: September 2007

Pressure‐dependent transmittance measurements on films of unoriented and oriented single‐walled carbon nanotubes were carried out at room temperature in the midinfrared up to the visible frequency range. The optical transitions in the SWNTs show anomalies at around 2 GPa, which can be attributed to a structural phase transition. The shift to lower frequencies and broadening of the absorption bands with increasing pressure could be attributed to the structural deformation of the SWNTs. We found no indications for a pressure‐induced dimensional crossover in the oriented SWNTs. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rapid mass spectral identification of contryphans. Detection of characteristic peptide ions by fragmentation of intact disulfide‐bonded peptides in crude venom
Authors: Thakur Suman S. , Balaram Padmanabhan
Published: September 2007

The mass spectrometric cleavage of intact disulfide‐bonded peptides in conus venom has been investigated. Contryphans containing a single disulfide bond are shown to fragment preferentially at X–Pro bonds, giving rise to linearized, unsymmetrical cystine peptides, which subsequently fragment by multiple pathways at the disulfide bridge. Cleavage at the disulfide bond can be initiated by initial loss of the CαH or CβH proton, resulting in distinct product ions, with the subsequent loss of elemental sulfur, H2S or H2S2. Contryphans from Conus amadis, Conus loroisii, and Conus striatus are presented as examples, in which detailed assignment of the product ions resulting from tandem mass spectrometric analysis of the intact disulfide is also accomplished. Characteristic fragments arising from conserved contryphan sequences can be used as diagnostic, permitting rapid identification of this class of peptides in crude venom. The observed fragment ions obtained for contryphans in diverse cone snail species are also compared. Copyright © 2007 John Wiley & Sons, Ltd.
Distribution of Traumatic and Other Stressful Life Events by Race/Ethnicity, Gender, SES and Age: A Review of the Research
Authors: Hatch Stephani L. , Dohrenwend Bruce P.
Published: September 2007

Much research has shown that reports of stressful life events are related to a wide variety of psychiatric and physical health outcomes. Relatively little research exists, however, on the distribution of the events according to gender, age, racial/ethnic background, and socioeconomic status (SES). Such information would help identify groups at greatest risk for further investigation. This paper presents a review of the relevant studies. We find that traumatic (e.g., life threatening) events appear to be more frequent for men, while men and women differ more consistently on types rather than on overall numbers of stressful events other than traumatic. Traumatic and other stressful events tend to be more frequent in low SES and racial/ethnic minorities groups, and finally, both traumatic and other stressful events are reported more by younger age groups in samples 18 years of age and older. The limitations and implications of these findings for further research and preventive interventions are discussed, especially the need for more detailed information about individual events.
“We Never was Happy Living Like a Whiteman” : Mental Health Disparities and the Postcolonial Predicament in American Indian Communities
Authors: Gone Joseph P.
Published: September 2007

In the context of increasing attention to disparities in health status between U.S. ethnoracial groups, this article examines the dilemma of divergent cultural practices for redressing disparities in mental health status in American Indian communities. Drawing upon an ethnographic interview with a tribal elder from a northern Plains Indian reservation, a prototypical discourse of distress is presented and analyzed as one exemplar of the divergence between the culture of the clinic and the culture of the community. Situated in the context of continuing power asymmetries between tribal nations and the U.S. federal government, the implications of this cultural divergence for the efforts of mental health professionals, practitioners, and policymakers are identified as a predicament that only the conventions and commitments of a robust community psychology have the potential to resolve.
The involuntary treatment of adolescent psychiatric inpatients—A nation‐wide survey from Finland
Authors: Ellila Heikki Toivo , Sourander Andre , Välimäki Maritta , Warne Tony , Kaivosoja Matti
Published: September 2007

This national cross‐sectional study investigates the prevalence rates, regional differences and factors associated with the involuntary inpatient treatment of adolescents in Finland on a chosen day in 2000. The proportion of inpatients with involuntary legal status was 29.5% (n=82) giving a prevalence rate of 2.5 per 10,000/12–17 years old inhabitants.

Forty‐eight per cent of involuntarily inpatients were 16–17 years old and 62% had psychotic disorders. Twenty‐six per cent of inpatients with involuntary legal status were voluntarily admitted. Regional differences of involuntary treatment were rather modest. Psychotic disorders, suicidal acts, and substance use disorders were independently associated with involuntary legal status.

There is a need for further studies to investigate the long‐term effects of involuntary treatment on the adolescents’ subsequent well‐being. Further studies on alternatives methods for involuntary treatment are warranted, likewise the clinical guidelines for involuntary treatment practices.
Characterization of proliferating cell nuclear antigen (PCNA) isoforms in normal and cancer cells: There is no cancer‐associated form of PCNA
Authors: Naryzhny Stanislav N. , Lee Hoyun
Published: September 2007

In order to clarify the status of PCNA in normal and transformed cells, we performed analysis of this protein by 2D‐PAGE, Western blot and mass spectrometry. All the cell lines examined contained the major PCNA form (pI 4.57/30 kDa), that is not post‐translationally modified. In addition to the major form, two minor isoforms (pI 4.52/30 kDa and pI 4.62/30 kDa) were also detected in all the cell lines examined. However, the level of PCNA in cancer cells is 5–6 folds higher than those in primary and most of the immortalized cells. Taken together, the significant difference in PCNA status between cancer and normal cells is not at the post‐translational modifications but in the overall levels of PCNA.
Linguistic constraints on children's ability to isolate phonemes in Arabic
Authors: SAIEGH-HADDAD ELINOR
Published: September 2007

The study tested the effect of three factors on Arab children's (N=256) phoneme isolation: phoneme's linguistic affiliation (standard phonemes vs. spoken phonemes), phoneme position (initial vs. final), and linguistic context (singleton vs. cluster). Two groups of children speaking two different vernaculars were tested. The two vernaculars differed with respect to whether they included four critical Standard Arabic phonemes. Using a repeated-measure design, we tested children's phonemic sensitivity toward these four phonemes versus other phonemes. The results showed that the linguistic affiliation of the phoneme was reliable in explaining phoneme isolation reaffirming, hence the external validity of the linguistic affiliation constraint in explaining phoneme awareness in diglossic Arabic. The results also showed that initial phonemes and initial singleton phonemes were particularly difficult for children to isolate. These findings were discussed in light of a stipulated unique phonological and orthographic cohesion of the consonant–vowel unit in Arabic.
Processing verb argument structure across languages: Evidence for shared representations in the bilingual lexicon
Authors: SALAMOURA ANGELIKI , WILLIAMS JOHN N.
Published: September 2007

Although the organization of first language (L1) and second language (L2) lexicosemantic information has been extensively studied in the bilingual literature, little evidence exists concerning how syntactic information associated with words is represented across languages. The present study examines the shared or independent nature of the representation of verb argument structure in the bilingual mental lexicon and the contribution of constituent order and thematic role information in these representations. In three production tasks, Greek (L1) advanced learners of English (L2) generated an L1 prime structure (Experiment 1: prepositional object [PO] and double object [DO] structures; Experiment 2: PO, DO, and intransitive structures; Experiment 3: PO, DO, locative, and “provide(someone)with(something)” structures) before completing an L2 target structure (PO or DO only). Experiment 1 showed L1-to-L2 syntactic priming; participants tended to reuse L1 structure when producing L2 utterances. Experiments 2 and 3 showed that this tendency was contingent on the combination of both syntactic structure and thematic roles up to the first postverbal argument. Based on these findings, we outline a model of shared representations of syntactic and thematic information for L1 and L2 verbs in the bilingual lexicon.
Global ultrasonic system with selective activation for autonomous navigation of an indoor mobile robot
Authors: Yi Soo-Yeong
Published: September 2007

This paper presents a global ultrasonic system with selective activation algorithm for autonomous navigation of an indoor mobile robot. The global ultrasonic system consists of several ultrasonic transmitters fixed at reference positions in global coordinates and two receivers at moving coordinates of a mobile robot. By activating the ultrasonic transmitters through an radiofrequency (RF) channel, the robot is able to obtain distance information to the reference positions and localize itself in the global coordinates. Due to limitations in signal strength and beam width, the ultrasonic signals from some transmitters may not be delivered to the robot and the ultrasonic data become invalid. In order to improve the effectiveness of the global ultrasonic system, a so-called selective activation algorithm is developed. Based on the current position of the robot, the selective activation calls a proper ultrasonic transmitter and generates valid ultrasonic data at every sampling instant, resulting in faster, more accurate response for self-localization than does simple sequential activation. Path-following control experiments are conducted to verify the effectiveness of the self-localization based on the proposed selective activation algorithm with the global ultrasonic system.
Introduction: The Chinese Legal System Since 1995: Steady Development and Striking Continuities
Authors: Clarke Donald C.
Published: September 2007

In March 1995, The China Quarterly published a special issue devoted to developments in the Chinese legal system. That issue canvassed a wide range of subjects: the legislative process, the implementation of legislation via the interpretive practices of courts and administrative agencies as well as through the enforcement of civil judgements, the personnel staffing the system in the role of legal advisers, criminal law and human rights, the key area of foreign trade and investment law, and finally China's place and role in the international legal order.
China's Courts: Restricted Reform
Authors: Liebman Benjamin L.
Published: September 2007

China's courts have in recent years engaged in significant reforms designed to raise the quality of their work. Yet such top-down reforms have been largely technical and are not designed to alter courts' power. Courts have also encountered new challenges, including rising populist pressures, which may undermine their authority. The most important changes in China's courts have come from the ground up: local courts have engaged in significant innovation, and horizontal interaction among judges is facilitating the development of professional identity. Recent developments have largely avoided two central questions facing China's courts: why have courts been permitted to develop even limited new roles, and what additional roles, if any, may they play within the Chinese political system?
Amacrine cell contributions to red-green color opponency in central primate retina: A model study
Authors: LEBEDEV D.S. , MARSHAK D.W.
Published: September 2007

To investigate the contributions of amacrine cells to red-green opponency, a linear computational model of the central macaque retina was developed based on a published cone mosaic. In the model, amacrine cells of ON and OFF types received input from all neighboring midget bipolar cells of the same polarity, but OFF amacrine cells had a bias toward bipolar cells whose center responses were mediated by middle wavelength sensitive cones. This bias might arise due to activity dependent plasticity because there are midget bipolar cells driven by short wavelength sensitive cones in the OFF pathway. The model midget ganglion cells received inputs from neighboring amacrine cells of both types. As in physiological experiments, the model ganglion cells showed spatially opponent responses to achromatic stimuli, but they responded to cone isolating stimuli as though center and surround were each driven by a single cone type. Without amacrine cell input, long and middle wavelength sensitive cones contributed to both the centers and surrounds of model ganglion cell receptive fields. According to the model, the summed amacrine cell input was red-green opponent even though inputs to individual amacrine cells were unselective. A key prediction is that GABA and glycine depolarize two of the four types of central midget ganglion cells; this may reflect lower levels of the potassium chloride co-transporter in their dendrites.
Robust directional computation in on-off directionally selective ganglion cells of rabbit retina
Authors: GRZYWACZ NORBERTO M. , AMTHOR FRANKLIN R.
Published: September 2007

The spatial and temporal interactions in the receptive fields of On-Off directionally selective (DS) ganglion cells endow them with directional selectivity. Using a variety of stimuli, such as sinusoidal gratings, we show that these interactions make directional selectivity of the DS ganglion cell robust with respect to stimulus parameters such as contrast, speed, spatial frequency, and extent of motion. Moreover, unlike the directional selectivity of striate-cortex cells, On-Off DS ganglion cells display directional selectivity to motions not oriented perpendicularly to the contour of the objects. We argue that these cells may achieve such high robustness by combining multiple mechanisms of directional selectivity.
In memoriam
Authors: MILLER ROBERT F. , RAVIOLA ELIO
Published: September 2007

The vision research community lost a valuable colleague and friend when Ramon (Ray) Dacheux II died on May 30, 2006 at his home in Birmingham, Alabama. Ray was 58 and had been ill with a brain tumor for two years.
Conjugated linoleic acid (CLA) and obesity
Authors: Silveira Manuela-Belén , Carraro Raffaele , Monereo Susana , Tébar Javier
Published: September 2007

Background

The term conjugated linoleic acid (CLA) refers to several positional and geometric conjugated dienoic isomers of linoleic acid (LA), of which the trans-10,cis-12 isomer has been reported to reduce adiposity and increase lean mass in mice and other animals when included at ≤1% of the diet. However, most dietary CLA in humans is obtained from dairy products, accounting for the cis-9,trans-11 CLA isomer, also known as rumenic acid, for more than 90% of the total CLA intake. Commercial CLA preparations industrially produced, containing trans-10,cis-12 and cis-9,trans-11 CLA isomers in diverse proportions, are attracting consumers’ interest because of the purported body fat-lowering effects of CLA, coupled to the perception of a ‘natural’ compound devoid of harmful effects. Nevertheless, despite numerous studies on CLA effects on body composition for nearly a decade, the mechanisms by which CLA isomers elicit their effects remain largely unknown. The purpose of this paper is to provide an updated review of the studies performed on animals and humans, as well as to describe the potential mechanisms involved in CLA effects on body weight and composition and metabolism.

Method

Literature review.

Results

Experiments in humans have not been able to show a significant effect on body weight, body composition or weight regain related to either of the CLA isomers. In fact, some studies suggest a tendency towards a decrease in body fat mass and an increase in body lean mass, while some others raise concern about the possibility of deleterious effects of trans-10,cis-12 CLA on lipid profile, glucose metabolism and insulin sensitivity.

Conclusions

Evidence regarding effectiveness of CLA in humans is not concluding.
Drugs in the treatment of obesity: sibutramine, orlistat and rimonabant
Authors: Rubio Miguel A , Gargallo Manuel , Isabel Millán Ana , Moreno Basilio
Published: September 2007

Background

Modification of lifestyle is the main therapeutical approach in the treatment of obesity, but use to fail on long terms of time. Addition of anti-obesity drugs allows keeping the weight loss during years and improving obesity-related comorbidities.

Methods

This review is an actualisation on efficacy, safety and tolerability of the approved drugs on the long-term treatment of obesity (orlistat and sibutramine). New indications and effects of their use far beyond the weight loss are as well commented. Finally, potential benefits of the administration of CB1 antagonist rimonabant on the weight loss and cardiometabolic risk factors are analysed in detail.

Discussion

A decade of experience on the use of orlistat and sibutramine has demonstrated their higher efficacy on the weight loss when compared to placebo either on adult or teenage population as well as safety and tolerability on long-term administration. Beneficial effects on the lipid profile, glycosilated haemoglobin on diabetic patients, blood pressure and levels of inflammatory cytokines, contribute to decrease the cardiovascular risk on obese patients. Phase III clinical trials using rimonabant show additional benefits to the expected weight loss, mainly reducing visceral fat and cardiometabolic risk factors.

Conclusion

Pharmacological treatment of obesity must be considered as a therapeutical tool that has to be used together with long-term lifestyle changes, contributing to the body weight reduction as well as to the improvement of the cardiometabolic risk related to obesity.
Editorial
Authors: Lyman Charles
Published: September 2007

The Impact Factor data for 2006 is in, and we are pleased to announce that Microscopy and Microanalysis is ranked #2 among microscopy journals by the ISI Web of Science (Thomson Scientific). This ranking is based on the 2006 Impact Factor of 2.11 (an increase from the 2005 Impact Factor of 1.88).
Overdispersion in the Poisson Regression Model
Authors: Palmer A. , Losilla J.M. , Vives J. , Jiménez R.
Published: September 2007

Abstract. This simulation study compares different strategies to solve the problem of underestimating standard errors in the Poisson regression model when overdispersion is present. The study analyses the importance of sample size, Poisson distribution mean, and dispersion parameter in choosing the best index or estimate. Results show that standard error (SE) estimates obtained by resampling (nonparametric bootstrap and jackknife) are the least biased, followed by the direct index based on the χ2, and the so-called robust indexes, in third place. Nevertheless, the inefficiency of resampling estimates is also evident, especially in small samples.
Evidence for serpentinite fluid in convergent margin systems: The example of El Salvador (Central America) arc lavas
Authors: Tonarini Sonia , Agostini Samuele , Doglioni Carlo , Innocenti Fabrizio , Manetti Piero
Published: September 2007

A comprehensive geochemical study, including B, Pb, Sr, and Nd isotopes, has been carried out on El Salvador subduction‐related lavas. The rocks have arc‐type incompatible element distributions with high LILE/HFSE ratios, nearly constant 143Nd/144Nd (≈0.5130), and small differences in 207Pb/204Pb (15.53–15.57), whereas 87Sr/86Sr ranges from 0.7035 to 0.7039. Boron isotopic composition varies widely, between −2.7‰ and +6.3‰. The boron isotope signature points to involvement of fluid inputs from (1) a high‐δ11B serpentinite fluid from serpentized mantle wedge dragged beneath the volcanic arc or from the subducting lithosphere and (2) a low‐δ11B fluid from the progressive dehydration of subducted altered basaltic crust and/or sediments. The observed sample variability is explained with a model in which different proportions of serpentinite‐derived (10–50%) and slab‐derived fluids are added to an enriched‐DMM source, triggering its partial melting. We suggest a model in which tectonic erosion, i.e., dragging down of slivers of serpentinized upper plate mantle, was responsible for the occurrence of serpentinite reservoir, 11B‐enriched in the forearc by shallow fluids.
Infrasonic monitoring at Stromboli volcano during the 2003 effusive eruption: Insights on the explosive and degassing process of an open conduit system
Authors: Ripepe Maurizio , Marchetti Emanuele , Ulivieri Giacomo
Published: September 2007

Stromboli is an open conduit volcano characterized by persistent conduit degassing and explosive dynamics. During the 2003 effusive eruption we monitored this activity with a five‐element array deployed at ∼450 m from the active craters. The array allows us to track in real time changes of explosive activity in terms of source position and excess pressure release. Infrasonic monitoring located the new active vents in the same preeruptive position, revealing that the collapse of the crater terrace has not changed the geometry of the shallow feeding system. Elevation of the infrasonic source is stable at ∼750 m above sea level, coincident with the elevation of the crater terrace. This suggests a shallow position of the magma column or, if the source is embedded in the conduit, diffraction at the crater rim. At the end of the eruption, back azimuth analysis indicates that explosive activity was progressively reestablished at all of the craters following a NE toward SW direction along the collapsed trench. The array detected significant small‐amplitude (∼1 Pa) infrasonic activity occurring at a rate of approximately one pulse every 2 s and generally located in only one vent at a time. This persistent activity is not related to Strombolian explosion, but we infer it is reflecting the overpressurized degassing of the magma column. Amplitude distribution of ∼7 million infrasonic signals shows that this degassing is 1 order of magnitude more energetic than the explosions. Besides, infrasonic amplitude distribution presents a decay with a double slope, indicating that explosions and degassing are driven by conduit dynamics acting at two different rates.
Stereological analysis of fractures in the Roselend tunnel and permeability determination
Authors: Patriarche Delphine , Pili Eric , Adler Pierre Michel , Thovert Jean‐François
Published: September 2007

Fracture traces and water fluxes have been determined along the 128 m long Roselend tunnel (French Alps). Fractures can be classified into two families: large fractures which intersect the tunnel and small fractures which partially intersect it. Three different zones in the tunnel are distinguished with mild, low, and high water fluxes, starting from the entrance. A stereological analysis of the trace length probability densities of small fractures provides the fracture diameter probability density distribution which is best approximated by a power law. Large fractures are assumed monodisperse, with a 5 m estimated radius. The generated fracture networks obtained by combining large and small fractures do percolate, while networks consisting of only small fractures do not percolate. Computed macroscopic permeabilities of the fracture networks are in agreement with the observed water fluxes when the fracture permeability is a power law of its lateral extent with an exponent equal to 3.
Anthropocene changes in desert area: Sensitivity to climate model predictions
Authors: Mahowald Natalie M.
Published: September 2007

Changes in desert area due to humans have important implications from a local, regional to global level. Here I focus on the latter in order to better understand estimated changes in desert dust aerosols and the associated iron deposition into oceans. Using 17 model simulations from the World Climate Research Programme's Coupled Model Intercomparison Project phase 3 multi‐model dataset and the BIOME4 equilibrium vegetation model, I estimate changes in desert dust source areas due to climate change and carbon dioxide fertilization. If I assume no carbon dioxide fertilization, the mean of the model predictions is that desert areas expand from the 1880s to the 2080s, due to increased aridity. If I allow for carbon dioxide fertilization, the desert areas become smaller. Thus better understanding carbon dioxide fertilization is important for predicting desert response to climate. There is substantial spread in the model simulation predictions for regional and global averages.
Sensing hypoxia in the carotid body: from stimulus to response
Authors: Kumar Prem
Published: September 2007

The carotid body is a peripheral sensory organ that can transduce modest falls in the arterial PO2 (partial pressure of oxygen) into a neural signal that provides the afferent limb of a set of stereotypic cardiorespiratory reflexes that are graded according to the intensity of the stimulus. The stimulus sensed is tissue PO2 and this can be estimated to be around 50 mmHg during arterial normoxia, falling to between 10–40 mmHg during hypoxia. The chemoafferent hypoxia stimulus-response curve is exponential, rising in discharge frequency with falling PO2, and with no absolute threshold apparent in hyperoxia. Although the oxygen sensor has not been definitely identified, it is believed to reside within type I cells of the carotid body, and presently two major hypotheses have been put forward to account for the sensing mechanism. The first relies upon alterations in the cell energy status that is sensed by the cytosolic enzyme AMPK (AMP-activated protein kinase) subsequent to hypoxia-induced increases in the cellular AMP/ATP ratio during hypoxia. AMPK is localized close to the plasma membrane and its activation can inhibit both large conductance, calcium-activated potassium (BK) and background, TASK-like potassium channels, inducing membrane depolarization, voltage-gated calcium entry and neurosecretion of a range of transmitter and modulator substances, including catecholamines, ATP and acetylcholine. The alternative hypothesis considers a role for haemoxygenase-2, which uses oxygen as a substrate and may act to gate an associated BK channel through the action of its products, carbon monoxide and possibly haem. It is likely however, that these and other hypotheses of oxygen transduction are not mutually exclusive and that each plays a role, via its own particular sensitivity, in shaping the full response of this organ between hyperoxia and anoxia.
Critical Difference Table for Word Recognition Testing Derived Using Computer Simulation
Authors: Carney Edward , Schlauch Robert S.
Published: September 2007

Purpose

To construct a table for upper and lower limits of the 95% critical range for changes in word recognition scores obtained with monosyllabic word lists (of lengths 10, 25, 50, and 100 words) using newly available methods. Although such a table has been available for nearly 30 years (A. R. Thornton & M. J. M. Raffin, 1978), the earlier table was constructed by calculation and used an approximation to the variance of the difference score between 2 administrations of word lists of identical size. It has been used clinically, reproduced, and recommended for use by clinicians in handbooks and textbooks.

Method

The new table was created using computer simulation of the relevant distributions and a direct estimate of the variance of the difference score between 2 tests, calculated using the simulated results.

Results

The new table differed from the previous table in 23% of entries. Critical ranges were both narrowed (82%) and expanded (18%). No range changed by more than 1 word correct in any direction. The original table was most accurate for list sizes of 25 words each.

Conclusion

Using the new table will provide more accurate estimates of the 95% critical range for successive administrations of word recognition tests.
Contribution of Two Sources of Listener Knowledge to Intelligibility of Speakers With Cerebral Palsy
Authors: Hustad Katherine C.
Published: September 2007

Purpose

This study examined the independent and combined effects of two sources of linguistic knowledge (alphabet cues and semantic predictability) on the intelligibility of speakers with dysarthria. The study also examined the extent to which each source of knowledge accounted for variability in intelligibility gains.

Method

Eight speakers with cerebral palsy and dysarthria contributed speech samples, and 128 listeners transcribed the speech samples (16 listeners per speaker) in 4 different conditions (no cues and unpredictable sentences; no cues and predictable sentences; alphabet cues and unpredictable sentences; alphabet cues and predictable sentences). Listener transcription results were the dependent variable and were scored as the percentage of words identified correctly by listeners.

Results

Both alphabet cues and semantic predictability made independent and overlapping contributions to intelligibility. In addition, alphabet cues accounted for more of the variability in gain scores than semantic predictability. Inseparable joint effects from the two sources of knowledge also made an important contribution to intelligibility.

Conclusion

Alphabet cues may be a more powerful source of information for resolving lexical ambiguity than semantic predictability for listeners who are faced with dysarthric speech.
Acquisition of English Grammatical Morphology by Native Mandarin-Speaking Children and Adolescents: Age-Related Differences
Authors: Jia Gisela , Fuse Akiko
Published: September 2007

Purpose

This 5-year longitudinal study investigated the acquisition of 6 English grammatical morphemes (i.e., regular and irregular past tense, 3rd person singular, progressive aspect –
ing
, copula BE, and auxiliary DO) by 10 native Mandarin-speaking children and adolescents in the United States (arrived in the United States between 5 and 16 years of age). The goals were to chart and compare the acquisition trajectories and levels of mastery across the morphemes, identify when age-related differences emerged and which forms they took.

Method

Morphological proficiency was measured by the accuracy of these morphemes in obligatory contexts during spontaneous speech.

Results

The morphemes were mastered by different numbers of participants and showed different growth trajectories. Performance variance was partially predicted by age of arrival (AoAr) in the United States, with early arrivals achieving greater proficiency than late arrivals. However, such AoAr effects took several years to occur and only existed for 2 of the 6 morphemes (i.e., 3rd person singular and regular past tense). Growth curve analysis revealed that language environment was a stronger predictor of individual differences than AoAr. Results did not uncover age-related differences in the acquisition of tense versus non-tense-related morphemes, nor in regular versus irregular morphemes, nor in the error types.

Conclusion

Findings support an Environmental account for age-related differences in 2nd language (L2) morphological acquisition. Results also indicate that the acquisition of some grammatical morphemes by school-aged immigrants takes several years to complete. As L2 learners exhibit some error types and difficulties similar to monolingual children with specific language impairment, caution needs to be taken when interpreting and using morphological errors as indicators of speech/language learning problems in this population.
Language Development and Mild-to-Moderate Hearing Loss: Does Language Normalize With Age?
Authors: Delage Hélène , Tuller Laurice
Published: September 2007

Purpose

The authors' purpose was to explore the nature of the link between hearing loss (HL) and language impairment in adolescents with mild-to-moderate hearing loss (MMHL). Does language performance (generally or in certain areas) normalize at adolescence?

Method

The language skills of 19 French-speaking adolescents (ages 11–15) with moderate or mild sensorineural HL were evaluated via a series of tests assessing oral and written language, including an experimental probe, and compared with typically developing adolescents and adolescents with specific language impairment (SLI).

Results

Language disorders were found, notably in the areas of phonology and grammar, in more than half the adolescents with MMHL; affected domains and error patterns were identical to those found in adolescents with SLI. Language scores of the adolescents with MMHL were significantly linked with degree of HL, a correlation not generally found in studies of children with MMHL.

Conclusion

Normalization of language performance does not generalize at adolescence in the context of MMHL. The fact that an effect of the severity of HL was found only after childhood might be because linguistic development is basically complete at adolescence. Prior to this time, this effect could be obscured by developmental rhythms that vary from child to child.
Construction of Graphic Symbol Utterances by Children, Teenagers, and Adults: The Effect of Structure and Task Demands
Authors: Trudeau Natacha , Sutton Ann , Dagenais Emmanuelle , de Broeck Sophie , Morford Jill
Published: September 2007

Purpose

This study investigated the impact of syntactic complexity and task demands on construction of utterances using picture communication symbols by participants from 3 age groups with no communication disorders.

Method

Participants were 30 children (7;0 [years;months] to 8;11), 30 teenagers (12;0 to 13;11), and 30 adults (18 years and above). All participants constructed graphic symbol utterances to describe photographs presented with spoken French stimuli. Stimuli included simple and complex (object relative and subject relative) utterances describing the photographs, which were presented either 1 at a time (neutral condition) or in an array of 4 (contrast condition).

Results

Simple utterances lead to more uniform response patterns than complex utterances. Among complex utterances, subject relative sentences appeared more difficult to convey. Increasing the need for message clarity (i.e., contrast condition) elicited changes in the production of graphic symbol sequences for complex propositions. The effects of syntactic complexity and task demands were more pronounced for children.

Conclusion

Graphic symbol utterance construction appears to involve more than simply transferring spoken language skills. One possible explanation is that this type of task requires higher levels of metalinguistic ability. Clinical implications and directions for further research are discussed.
Intervention for Verb Argument Structure in Children With Persistent SLI: A Randomized Control Trial
Authors: Ebbels Susan H. , van der Lely Heather K. J. , Dockrell Julie E.
Published: September 2007

Purpose

The authors aimed to establish whether 2 theoretically motivated interventions could improve use of verb argument structure in pupils with persistent specific language impairment (SLI).

Method

Twenty-seven pupils with SLI (ages 11;0–16;1) participated in this randomized controlled trial with “blind” assessment. Participants were randomly assigned to 1 of 3 therapy groups: syntactic–semantic, semantic, and control. All pupils received 9 weekly half-hour individual therapy sessions. They were assessed on a specifically designed video test pretherapy, posttherapy, and at follow-up.

Results

Pupils receiving the syntactic–semantic and semantic therapies made significant progress (
d
> 1.0), which was maintained at follow-up and generalized to control verbs. Both therapies improved linking of arguments to syntax, and the syntactic–semantic therapy tended to increase use of optional arguments. Pupils receiving the control therapy made no progress.

Conclusion

Both methods of argument structure therapy were effective. Comparisons of their effectiveness in specific areas led to the hypotheses that the pupils' initial difficulties with linking resulted from ill-defined semantic representations, whereas their limited use of arguments may have resulted from syntactic difficulties. When therapy is theoretically grounded, it can inform theories, be time limited, and be effective for older children with SLI.