bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuropsychological functioning of U.S. Gulf War veterans 10 years after the war
Authors: TOOMEY ROSEMARY , ALPERN RENEE , VASTERLING JENNIFER J. , BAKER DEWLEEN G. , REDA DOMENIC J. , LYONS MICHAEL J. , HENDERSON WILLIAM G. , KANG HAN K. , EISEN SETH A. , MURPHY FRANCES M.
Published: July 2009

Many U.S. Gulf War-era veterans complained of poor cognition following the war. This study assessed neuropsychological functioning in veterans 10 years after the war through objective tests. 2189 Gulf War-era veterans (1061 deployed, 1128 non-deployed) were examined at 1 of 16 U.S. Veterans Affairs medical centers. Outcomes included neuropsychological domains derived from factor analysis and individual test scores. Deployed veterans performed significantly worse than non-deployed veterans on 2 of 8 factors (motor speed & sustained attention, analysis not corrected for multiple comparisons) and on 4 of 27 individual test variables (Trails A & B, California Verbal Learning Test – List B, and Continuous Performance Test sensitivity, with only Trails B surviving Bonferroni correction). Within deployed veterans, Khamisiyah exposure was negatively correlated with motor speed after controlling for emotional distress. Depressive symptoms and self-reported exposure to toxicants were independently and significantly associated with worse sustained attention. Other factors were also associated with self-reported exposures. The findings were not a result of differential effort across groups. Gulf War deployment is associated with subtle declines of motor speed and sustained attention, despite overall intact neuropsychological functioning. Evidence suggests that toxicant exposures influence both these functions, and depressive symptoms also influence attention. (JINS, 2009, 15, 717–729.)
A CLASS OF MIX DESIGN PROBLEMS: FORMULATION, SOLUTION METHODS AND APPLICATIONS
Authors: Wan Zhong , Teo K. L. , Kong LingShuang , Yang Chunhua
Published: July 2009

In this paper, we consider a linear program with only equality constraints but containing interval and random coefficients. We first address the linear program with interval coefficients, and establish some structural properties of this linear program. On this basis, a solution method is proposed. We then move on to consider the linear program with random coefficients. Using the chance constraint approach and a new approach, the satisfaction degree approach, we obtain the two respective deterministic equivalent formulations. Then the results and the numerical solution methods obtained for these two linear models are applied to the original linear problem which contains both interval and random coefficients. By way of illustration, we consider a practical problem, where the optimal mixing proportions need to be determined for the mix slurry in the production process of aluminium with sintering. This gives rise to a linear program with interval and random coefficients. Its deterministic equivalent formulations are presented. Preliminary numerical examples show that the proposed models and the solution methods are promising.
Selection of alfalfa cultivars adapted for tropical environments with repeated measures using PROC MIXED of SAS® System
Authors: de Assis G. M. L. , Ruggieri A. C. , Mercadante M. E. Z. , de Camargo G. M. F. , Carneiro Júnior J. M.
Published: July 2009

Although alfalfa (Medicago sativa L.) is a leguminous herbage widely used in temperate regions as animal feed, there is not much research in tropical regions to develop cultivars adapted to these environmental conditions. The utilization of adapted cultivars with adequate management practices is important to improve productivity, quality and persistence of cultivated pastures. The objectives of this study were to verify the genetic variability among alfalfa cultivars and to rank them using mixed model methodology. A total of 35 alfalfa cultivars were evaluated in the rainy and dry seasons, from 1996 to 2000, in plots of 2.8 m2 in Sertãozinho, São Paulo, Brazil. The experimental design was a randomized complete block with three replications. Longitudinal data of dry matter yield were analyzed using PROC MIXED of SAS® System. Several covariance structures were tested and the spherical spatial structure was selected. The results show that the genetic variability was statistically significant only for the dry season. Moreover, the interaction among cultivars and harvests variance was highly significant for both seasons. The empirical best linear unbiased predictions of cultivar effects were obtained, allowing for the selection of the superior cultivars MH 15, 5715, SW 8210, Rio, High, 5888, Monarca, Victoria, Florida 77 and Falcon. Crioula, the most common cultivar in Brazil, showed low forage potential in Sertãozinho. Results indicate potential for use of more productive cultivars of alfalfa to produce animal feed in tropical environments.
Effects of restorative agroecosystems on soil characteristics and plant production on a degraded soil in the Georgia Piedmont, USA
Authors: Jacobsen K.L. , Jordan C.F.
Published: July 2009

This work presents the results of a three-year field study of agroecosystems designed to restore soil organic matter (SOM) to degraded soils of the Georgia Piedmont. The systems combine a suite of management practices previously demonstrated to increase SOM when studied individually, and examine the effects of these techniques when used in combination in a cropping systems context on soil characteristics, crop production and weed biomass. The systems' components include organic management, alley cropping with perennial legumes, conservation tillage, use of winter cover crops, straw mulch and two compost application rates. Vegetable crops grown were a rotation of okra, hot pepper and a corn and winter squash intercrop. The systems were not able to maintain soil C or N without the addition of compost. Systems incorporating alley cropping, organic management, conservation tillage and compost maintained soil C, and increased in soil C when mulch was not applied. In organic, conservation tillage without alley cropping, soil C did not change significantly, even with annual 44.8 Mg ha−1of compost additions. Patterns for soil N followed those of soil C. The study demonstrated that alley cropping can maintain and sequester soil C and N beyond organic conservation tillage alone, and more than conventionally tilled, chemically fertilized treatments. Crop yields did not vary by treatment due to high variation within treatments. Winter cover crop residue provided an effective weed barrier for 4 to 6 weeks in the spring, but additional hand weeding was required throughout the summer. The results of this systems-level study demonstrated interactions between management practices when used in combination that would not have been observed when studied individually. It also demonstrates that agroforestry techniques, conservation tillage and compost applications can increase soil C in degraded, clayey soils while they are in cultivation.
Das akute oder rasch fortschreitende Nierenversagen im Alter
Authors: Cohen
Published: July 2009

Ältere Patienten sind besonders gefährdet, ein akutes oder rasch fortschreitendes Nierenversagen (A/RNV) zu erleiden. Das akute Nierenversagen ist eine häufige Komplikation in der Klinik, während die rasch fortschreitende Nierenfunktionsverschlechterung in der Praxis erkannt werden muss. Unterschiedliche Ursachen können dieser Verschlechterung der Nierenfunktion zu Grunde liegen. Dem akuten, das heisst innerhalb von Stunden oder wenigen Tagen auftretenden, Nierenversagen liegt häufig eine akute Tubulusnekrose zu Grunde, die von prä- und postrenalen Ursachen zu unterscheiden ist. Bei einer über Wochen fortschreitenden Verschlechterung der Nierenfunktion ist an andere Differentialdiagnosen zu denken. So ist die rapidprogressive Glomerulonephritis möglichst früh zu diagnostizieren, denn sie bedarf dringlich einer Therapie. Ebenfalls eine häufige Ursache für ein rasch fortschreitendes Nierenversagen im Alter ist die interstitielle Nephritis, welche oft durch Umstellung der Medikation ursächlich behandelt werden kann. Weitere Differentialdiagnosen werden im Artikel genannt.
Laterally heterogeneous scattering explains Lg blockage in the Pyrenees
Authors: Sens‐Schönfelder C. , Margerin L. , Campillo M.
Published: July 2009

We present an algorithm to simulate the propagation of seismic energy in a model that contains both deterministic structure and statistically described small‐scale heterogeneities. With this algorithm, we study the propagation of seismic waves through the Pyrenees. Using a series of seismograms, the variations of the attenuation properties of the crust along the Pyrenean axis are illustrated. The western Pyrenees exhibit strong attenuation of crustal phases, a phenomenon known as Lg blockage. Previous studies demonstrated that the large‐scale velocity structure of the western Pyrenees cannot explain the strong lateral variations of attenuation along the Pyrenean range. In this paper we present a model that is able to explain the principal observations. We propose that the Lg blockage is caused by a perturbed region of the crust with scattering and anelastic properties that differ markedly from the surrounding crust. Numerical simulations of the elastic radiative transfer equation in a layered medium show that it is possible to model the observed Lg blockage with increased scattering in the perturbed body. In order to explore the relative importance of scattering and attenuation we performed an inversion of the data using a genetic algorithm. Our study reveals that stronger intrinsic attenuation in the perturbed body improves the fit to the data but that intrinsic attenuation alone cannot explain the observations. Our work puts forward the role of multiple scattering in the attenuation mechanism of crustal phases.
Cloud condensation nuclei activity, closure, and droplet growth kinetics of Houston aerosol during the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS)
Authors: Lance Sara , Nenes Athanasios , Mazzoleni Claudio , Dubey Manvendra K. , Gates Harmony , Varutbangkul Varuntida , Rissman Tracey A. , Murphy Shane M. , Sorooshian Armin , Flagan Richard C. , Seinfeld John H. , Feingold Graham , Jonsson Haflidi H.
Published: July 2009

In situ cloud condensation nuclei (CCN) measurements were obtained in the boundary layer over Houston, Texas, during the 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) campaign onboard the CIRPAS Twin Otter. Polluted air masses in and out of cloudy regions were sampled for a total of 22 flights, with CCN measurements obtained for 17 of these flights. In this paper, we focus on CCN closure during two flights, within and downwind of the Houston regional plume and over the Houston Ship Channel. During both flights, air was sampled with particle concentrations exceeding 25,000 cm−3 and CCN concentrations exceeding 10,000 cm−3. CCN closure is evaluated by comparing measured concentrations with those predicted on the basis of measured aerosol size distributions and aerosol mass spectrometer particle composition. Different assumptions concerning the internally mixed chemical composition result in average CCN overprediction ranging from 3% to 36% (based on a linear fit). It is hypothesized that the externally mixed fraction of the aerosol contributes much of the CCN closure scatter, while the internally mixed fraction largely controls the overprediction bias. On the basis of the droplet sizes of activated CCN, organics do not seem to impact, on average, the CCN activation kinetics.
Insight into complex rupturing of the immature bending normal fault in the outer slope of the Japan Trench from aftershocks of the 2005 Sanriku earthquake (Mw = 7.0) located by ocean bottom seismometry
Authors: Hino Ryota , Azuma Ryosuke , Ito Yoshihiro , Yamamoto Yojiro , Suzuki Kensuke , Tsushima Hiroaki , Suzuki Syuichi , Miyashita Makoto , Tomori Toshihiro , Arizono Mitsuharu , Tange Go
Published: July 2009

The distribution of aftershocks of a large (Mw = 7.0) normal faulting earthquake beneath the outer slope of the Japan Trench in 2005, measured in 2007 using ocean bottom seismographs, indicates that the earthquake was involved with a set of conjugate normal faults. Although the faults reach to the upper mantle, the estimated Vp and Vp/Vs show no remarkable changes that can be related to extensive hydration in the crust or uppermost mantle. The absence of horst‐graben topographic structure in the rupture area suggests that immaturity of the bending fault system is responsible for the relatively unhydrated lithosphere. Several earthquakes below the aftershock zone may belong to the lower plane seismicity of the shallow double seismic zone. Because no earthquakes were recorded in the area for more than 80 years before the 2005 event, shallow extensional and deep compressive earthquakes may be activated concurrently in the focal area of this earthquake.
Anomalous biogeochemical conditions in the northern South China Sea during the El‐Niño events between 1997 and 2003
Authors: Tseng C.‐M. , Gong G.‐C. , Wang L.‐W. , Liu K.‐K. , Yang Y.
Published: July 2009

Anomalous biogeochemical conditions were observed at the SouthEast Asian Time‐series Study (SEATS) station in the northern South China Sea (SCS) during the 1997–98 and 2002–03 El Niño events. The time‐series records showed decreases of monthly mean sea surface chlorophyll‐a (S‐chl) (and integrated primary production, IPP) by 42% (and 42%) and 13% (and 10%), respectively, below the climatological mean in the winter months (DJF) of the two events. The negative anomalies in S‐chl and IPP corresponded to elevated sea surface temperature by 1.2°C and 0.4°C, respectively, above the climatological mean, while the mean wind speed was reduced by about 20% and 11%, respectively. Statistical analysis demonstrated the reduction in S‐chl and IPP during El Niño events was caused by the diminished vertical mixing and strengthened stratification. Regional anomalies in hydrographic and biological conditions in the northern SCS (15–21°N and 112–119°E) were consistent with those found at the SEATS site.
Transient intensity changes of cosmic rays beyond the heliospheric termination shock as observed at Voyager 1
Authors: Webber W. R. , Cummings A. C. , McDonald F. B. , Stone E. C. , Heikkila B. , Lal N.
Published: July 2009

This paper continues our studies of temporal variations of cosmic rays beyond the heliospheric termination shock (HTS) using Voyager 1 (V1) data when V1 was beyond 94 AU. This new study utilizes cosmic ray protons and electrons of several energies. Notable transient decreases of 5–50% are observed in galactic cosmic ray nuclei and electrons at V1 shortly after similar decreases are observed at Voyager 2 (V2) still inside the HTS. These decreases at V1 appear to be related to the large solar events in September 2005 and December 2006 and the resulting outward moving interplanetary shock. These two large interplanetary shocks were the largest observed at V2 after V1 crossed the HTS at the end of 2004. They were observed at V2 just inside the HTS at 2006.16 and 2007.43 providing timing markers for V1. From the timing of the intensity decreases observed at V1 as the shocks first reach the HTS and then later reach V1 itself, we can estimate the shock speed beyond the HTS to be between 240 and 300 km s−1 in both cases. From the timing of the decreases observed when the shock first reaches the HTS and then several months later encounters the heliopause, we can estimate the heliosheath thickness to be 31 ± 4 and 37 ± 6 AU, respectively, for the two sequences of three decreases seen at V1. These values, along with the distances to the HTS that are determined, give distances from the Sun to the heliopause of 121 ± 4 and 124 ± 6 AU, respectively.
Expression and Induction of p-Glycoprotein-1 on Cultured Human Brain Endothelium
Authors: Male David K
Published: July 2009

The ABC-transporter, p-glycoprotein-1 (pgp-1), is expressed on brain endothelium and is reported to be induced by several cytotoxic drugs, which are themselves substrates of pgp-1. Pgp-1 was increased on a human brain endothelial cell line (hCMEC/D3) after treatment with puromycin or verapamil. However, flow cytometry showed that the apparent upregulation caused by puromycin was not because of a global increase in expression levels, but selective cell death of a subpopulation of endothelium expressing the lowest levels of pgp-1. If a cytotoxic substrate of pgp-1 increases pgp-1 expression in vitro, it can easily be misinterpreted as a transcriptional activator of pgp-1.
Studying the Neurovascular Unit: An Improved Blood–Brain Barrier Model
Authors: Zehendner Christoph M , Luhmann Heiko J , Kuhlmann Christoph RW
Published: July 2009

The blood–brain barrier (BBB) closely interacts with the neuronal parenchyma in vivo. To replicate this interdependence in vitro, we established a murine coculture model composed of brain endothelial cell (BEC) monolayers with cortical organotypic slice cultures. The morphology of cell types, expression of tight junctions, formation of reactive oxygen species, caspase-3 activity in BECs, and alterations of electrical resistance under physiologic and pathophysiological conditions were investigated. This new BBB model allows the application of techniques such as laser scanning confocal microscopy, immunohistochemistry, fluorescent live cell imaging, and electrical cell substrate impedance sensing in real time for studying the dynamics of BBB function under defined conditions.
Atorvastatin Extends the Therapeutic Window for tPA to 6 h after the Onset of Embolic Stroke in Rats
Authors: Zhang Li , Chopp Michael , Jia Longfei , Cui Yisheng , Lu Mei , Zhang Zheng Gang
Published: July 2009

We investigated the neuroprotective effect of atorvastatin in combination with delayed thrombolytic therapy in a rat model of embolic stroke. Rats subjected to embolic middle cerebral artery (MCA) occlusion were treated with atorvastatin at 4 h, followed by tissue plasminogen activator (tPA) at 6 or 8 h after stroke. The combination of atorvastatin at 4 h and tPA at 6 h significantly decreased the size of the embolus at the origin of the MCA, improved microvascular patency, and reduced infarct volume, but did not increase the incidence of hemorrhagic transformation compared with vehicle-treated control animals. However, monotherapy with tPA at 6 h increased the incidence of hemorrhagic transformation and failed to reduce infarct volume compared with the control group. In addition, adjuvant treatment with atorvastatin at 4 h and with tPA at 6 h reduced tPA-induced upregulation of protease-activated receptor-1, intercellular adhesion molecule-1, and matrix metalloproteinase-9, and concomitantly reduced cerebral microvascular platelet, neutrophil, and fibrin deposition compared with rats treated with tPA alone at 6 h. In conclusion, a combination of atorvastatin and tPA extended the therapeutic window for stroke to 6 h without increasing the incidence of hemorrhagic transformation. Atorvastatin blocked delayed tPA-potentiated adverse cerebral vascular events, which likely contributes to the neuroprotective effect of the combination therapy.
Using Ontology Fingerprints to Evaluate Genome-wide Association Results
Authors: Tsoi Lam , Boehnke Michael , Klein Richard , Zheng Jim
Published: July 2009

We describe an approach to characterize genes or phenotypes via ontology fingerprints which are composed of Gene Ontology (GO) terms overrepresented among those PubMed abstracts linked to the genes or phenotypes. We then quantify the biological relevance between genes and phenotypes by comparing their ontology fingerprints to calculate a similarity score. We validated this approach by correctly identifying genes belong to their biological pathways with high accuracy, and applied this approach to evaluate GWA study by ranking genes associated with the lipid concentrations in plasma as well as to prioritize genes within linkage disequilibrium (LD) block. We found that the genes with highest scores were: ABCA1, LPL, and CETP for HDL; LDLR, APOE and APOB for LDL; and LPL, APOA1 and APOB for triglyceride. In addition, we identified some top ranked genes linking to lipid metabolism from the literature even in cases where such knowledge was not reflected in current annotation of these genes. These results demonstrate that ontology fingerprints can be used effectively to prioritize genes from GWA studies for experimental validation.
Structure of a trimeric bacterial microcompartment shell protein, EtuB, associated with ethanol utilization inClostridium kluyveri
Authors: Heldt Dana , Frank Stefanie , Seyedarabi Arefeh , Ladikis Dimitrios , Parsons Joshua B. , Warren Martin J. , Pickersgill Richard W.
Published: July 2009

It has been suggested that ethanol metabolism in the strict anaerobe Clostridium kluyveri occurs within a metabolosome, a subcellular proteinaceous bacterial microcompartment. Two bacterial microcompartment shell proteins [EtuA (ethanol utilization shell protein A) and EtuB] are found encoded on the genome clustered with the genes for ethanol utilization. The function of the bacterial microcompartment is to facilitate fermentation by sequestering the enzymes, substrates and intermediates. Recent structural studies of bacterial microcompartment proteins have revealed both hexamers and pentamers that assemble to generate the pseudo-icosahedral bacterial microcompartment shell. Some of these shell proteins have pores on their symmetry axes. Here we report the structure of the trimeric bacterial microcompartment protein EtuB, which has a tandem structural repeat within the subunit and pseudo-hexagonal symmetry. The pores in the EtuB trimer are within the subunits rather than between symmetry related subunits. We suggest that the evolutionary advantage of this is that it releases the pore from the rotational symmetry constraint allowing more precise control of the fluxes of asymmetric molecules, such as ethanol, across the pore. We also model EtuA and demonstrate that the two proteins have the potential to interact to generate the casing for a metabolosome.
Syntactic Development in Adolescents With a History of Language Impairments: A Follow-Up Investigation
Authors: Nippold Marilyn A. , Mansfield Tracy C. , Billow Jesse L. , Tomblin J. Bruce
Published: July 2009

Purpose

Syntactic development in adolescents was examined using a spoken discourse task and standardized testing. The primary goal was to determine whether adolescents with a history of language impairments would differ from those with a history of typical language development (TLD). This is a companion study to one that examined these same adolescents 2 years earlier (M. A. Nippold, T. C. Mansfield, J. L. Billow, & J. B. Tomblin, 2008).

Method

The participants were 15-year-old adolescents with a history of specific language impairment (SLI;
n
= 102), nonspecific language impairment (NLI;
n
= 77), or TLD (
n
= 247). A sample of spoken discourse was elicited using a Peer Conflict Resolution (PCR) task and analyzed for mean length of T-unit, clausal density, and subordinate clause use. In addition, 2 subtests from the Clinical Evaluation of Language Fundamentals, Third Edition (E. Semel, E. H. Wiig, & W. A. Secord, 1995), Concepts and Directions and Recalling Sentences, were administered.

Results

On the PCR task, the TLD group outperformed the SLI and NLI groups on mean length of T-unit, clausal density, and nominal clause use, and the TLD group outperformed the NLI group on relative clause use. On the standardized testing, the TLD group outperformed the SLI and NLI groups, and the SLI group outperformed the NLI group. Correlation coefficients calculated between the nonstandardized and standardized measures of syntax were statistically significant and positive.

Conclusions

Speech-language pathologists may wish to employ the PCR task to examine syntactic development in adolescents as a supplement to standardized testing.
Refinement of Speech Breathing in Healthy 4- to 6-Year-Old Children
Authors: Boliek Carol A. , Hixon Thomas J. , Watson Peter J. , Jones Patricia B.
Published: July 2009

Purpose

The purpose of this study was to offer a better understanding of the development of neuromotor control for speech breathing and provide a normative data set that can serve as a useful standard for clinical evaluation and management of young children with speech disorders involving the breathing subsystem.

Method

Speech breathing was studied in 60 healthy children, including 10 boys and 10 girls, each at ages 4, 5, and 6 years. A variable inductance plethysmograph was used to obtain volume changes of the rib cage, abdomen, and lung as well as temporal features of the breathing cycle.

Results

Results indicated that breathing behavior was influenced by height and age but not gender. Some speech breathing behaviors were found to be highly variable, whereas others were more systematic.

Conclusions

The data from this investigation demonstrate that the refinement of the speech breathing mechanism is gradual and presumably takes place from approximately 3–10 years of age. The rate of change associated with speech breathing parallels that observed in other subsystems of speech production.
Auditory Event-Related Potentials (ERPs) in Audiovisual Speech Perception
Authors: Pilling Michael
Published: July 2009

Purpose

It has recently been reported (e.g., V. van Wassenhove, K. W. Grant, & D. Poeppel, 2005) that audiovisual (AV) presented speech is associated with an N1/P2 auditory event-related potential (ERP) response that is lower in peak amplitude compared with the responses associated with auditory only (AO) speech. This effect was replicated. Further comparisons were made between ERP responses to AV speech in which the visual and auditory components were in or out of synchrony, to test whether the effect is associated with the operation of integration mechanisms, as has been claimed, or occurs because of other factors such as attention.

Method

ERPs were recorded from participants presented with recordings of unimodal or AV speech syllables in a detection task.

Results

Comparisons were made between AO and AV speech and between synchronous and asynchronous AV speech. Synchronous AV speech produced an N1/P2 with lower peak amplitudes than with AO speech, unaccounted for by linear superposition of visually evoked responses onto auditory-evoked responses. Asynchronous AV speech produced no amplitude reduction.

Conclusion

The dependence of N1/P2 amplitude reduction on AV synchrony validates it as an electrophysiological marker of AV integration.
Safety of Electromagnetic Articulography in Patients With Pacemakers and Implantable Cardioverter-Defibrillators
Authors: Joglar Jose A. , Nguyen Carol , Garst Diane M. , Katz William F.
Published: July 2009

Purpose

Electromagnetic articulography (EMA)uses a helmet to create alternating magnetic fields for tracking speech articulator movement. An important safety consideration is whether EMA magnetic fields interfere with the operation of speakers' pacemakers or implantable cardioverter-defibrillators (ICDs). In this investigation, individuals with pacemaker/ICD devices were exposed to EMA fields under controlled conditions while potential interference was examined.

Method

Twelve adults with pacemaker/ICD devices from 3 major manufacturers were assessed for device function before, during, and after exposure to magnetic fields from a Carstens AG100 EMA system. Potential interference was probed, with EMA transmitters positioned at varying distances from the implantable devices and with the EMA system set at different operating strengths.

Results

No adverse affects in device operation were observed under any conditions. The only potential complication was temporary telemetry-link interference during device testing in some cases.

Conclusion

The results suggest that EMA technology may be safely used with patients who have pacemakers and ICDs. However, the present findings do not rule out potential interference with other pacemaker/ICD manufacturers or with different articulography systems. Precautions are suggested for testing individuals with pacemaker/ICDs under EMA conditions.
The Diagnostic Accuracy of a New Test of Early Nonword Repetition for Differentiating Late Talking and Typically Developing Children
Authors: Stokes Stephanie F. , Klee Thomas
Published: July 2009

Purpose

To assess the diagnostic accuracy of a new Test of Early Nonword Repetition (TENR) for 2-year-old children.

Method

232 British-English-speaking children aged 27 (±3) months were assessed on 3 standardized tests (receptive and expressive vocabulary and visual processing) and a novel nonword repetition (NWR) test. Parents completed a British adaptation of the MacArthur-Bates Communicative Development Inventory: Words and Sentences (CDI:WS–UK; Klee & Harrison, 2001). The diagnostic accuracy of two versions (1–3 syllables and 1–4 syllables) of a new NWR test was examined. Standard diagnostic accuracy measures of sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratios were generated.

Results

177 children (80%) completed the 1–3 syllable task, and 96 children (73%) completed the 1–4 syllable task. The 1–3 syllable version produced a positive likelihood ratio (LR+) of 7.8 (confidence interval [CI] = 4.5–13.6) and a negative likelihood ratio (LR–) of .28 (CI = .12–.65). The 1–4 syllable version of the NWR test produced a LR+ of 14.88 (CI = 6.1–36.2) and a LR– of .13 (CI = .02–.83).

Conclusion

The TENR could be useful for identifying 2-year-old children at risk of language impairment.
A Rat Excised Larynx Model of Vocal Fold Scar
Authors: Welham Nathan V. , Montequin Douglas W. , Tateya Ichiro , Tateya Tomoko , Choi Seong Hee , Bless Diane M.
Published: July 2009

Purpose

To develop and evaluate a rat excised larynx model for the measurement of acoustic, aerodynamic, and vocal fold vibratory changes resulting from vocal fold scar.

Method

Twenty-four 4-month-old male Sprague–Dawley rats were assigned to 1 of 4 experimental groups: chronic vocal fold scar, chronic vocal fold scar treated with 100-ng basic fibroblast growth factor (bFGF), chronic vocal fold scar treated with saline (sham treatment), and unscarred untreated control. Following tissue harvest, histological and immunohistochemical data were collected to confirm extracellular matrix alteration in the chronic scar group; acoustic, aerodynamic, and high-speed digital imaging data were collected using an excised larynx setup in all groups. Phonation threshold pressure (
P

th

), glottal resistance (
R

g

), glottal efficiency (
E

g

), vibratory amplitude, and vibratory area were used as dependent variables.

Results

Chronically scarred vocal folds were characterized by elevated collagen Types I and III and reduced hyaluronic acid abundance. Phonation was achieved, and data were collected from all control and bFGF-treated larynges; however, phonation was not achieved with 3 of 6 chronically scarred and 1 of 6 saline-treated larynges. Compared with control, the chronic scar group was characterized by elevated
P

th

,
reduced
E

g

,
and intralarynx vibratory amplitude and area asymmetry. The bFGF group was characterized by
P

th

below control-group levels,
E

g

comparable with control, and vocal fold vibratory amplitude and area symmetry comparable with control. The sham group was characterized by
P

th

comparable with control,
E

g

superior to control, and vocal fold vibratory amplitude and area symmetry comparable with control.

Conclusions

The excised larynx model reported here demonstrated robust deterioration across phonatory indices under the scar condition and sensitivity to treatment-induced change under the bFGF condition. The improvement observed under the sham condition may reflect unanticipated therapeutic benefit or artifact. This model holds promise as a tool for the functional characterization of biomechanical tissue changes resulting from vocal fold scar and the evaluation of experimental therapies.
African American English–Speaking Students: An Examination of the Relationship Between Dialect Shifting and Reading Outcomes
Authors: Craig Holly K. , Zhang Lingling , Hensel Stephanie L. , Quinn Erin J.
Published: July 2009

Purpose

In this study, the authors evaluated the contribution made by dialect shifting to reading achievement test scores of African American English (AAE)–speaking students when controlling for the effects of socioeconomic status (SES), general oral language abilities, and writing skills.

Method

Participants were 165 typically developing African American 1st through 5th graders. Half were male and half were female, one third were from low-SES homes, and two-thirds were from middle-SES homes. Dialect shifting away from AAE toward Standard American English (SAE) was determined by comparing AAE production rates during oral and written narratives. Structural equation modeling evaluated the relative contributions of AAE rates, SES, and general oral language and writing skills on standardized reading achievement scores.

Results

AAE production rates were inversely related to reading achievement scores and decreased significantly between the oral and written narratives. Lower rates in writing predicted a substantial amount of the variance in reading scores, showing a significant direct effect and a significant indirect effect mediated by measures of oral language comprehension.

Conclusion

The findings support a dialect shifting–reading achievement hypothesis, which proposes that AAE-speaking students who learn to use SAE in literacy tasks will outperform their peers who do not make this linguistic adaptation.
Phonation Threshold Pressure Measurement With a Semi-Occluded Vocal Tract
Authors: Titze Ingo R.
Published: July 2009

Purpose

The purpose of this article was to determine if a semi-occluded vocal tract could be used to measure phonation threshold pressure. This is in contrast to the shutter technique, where an alternation between a fully occluded tract and an unoccluded tract is used.

Method

Five male and 5 female volunteers phonated through a thin straw held between the lips. Oral pressure behind the lips was measured. Mathematical predictions of phonation threshold pressures were compared to the measured ones over a range of frequencies.

Results

It was shown that, for a 2.5-mm diameter straw, phonation threshold pressures were obtainable over a 2-octave range of fundamental frequency by all volunteers. In magnitude, the pressures agreed with the 0.2–0.5 kPa values obtained in previous investigations. Sensitivity to viscoelastic and geometric properties of the vocal folds was generally not compromised with greater oral impedance, but some differences were predicted theoretically in contrast to an open mouth configuration.

Conclusion

Because phonation threshold pressure is always dependent on vocal tract interaction, it may be advantageous to choose an exact and fixed oral semi-occlusion for the measurement and interpret the results in light of the known acoustic load.
Fast Fourier transform spectrometer readout for large arrays of microwave kinetic inductance detectors
Authors: Yates S. J. C. , Baryshev A. M. , Baselmans J. J. A. , Klein B. , Güsten R.
Published: July 2009

Microwave kinetic inductance detectors have great potential for large, very sensitive detector arrays for use in, for example, submillimeter imaging. Being intrinsically readout in the frequency domain, they are particularly suited for frequency domain multiplexing allowing ∼1000 s of devices to be readout with one pair of coaxial cables. However, this moves the complexity of the detector from the cryogenics to the warm electronics. We present here the concept and experimental demonstration of the use of fast Fourier transform spectrometer readout, showing no deterioration of the noise performance compared to the low noise analog mixing while allowing high multiplexing ratios.
Influence on the magnetoresistance of a spin valve due to the insertion of an ultrathin Gd layer in the free layer
Authors: Romera M. , Muñoz M. , Sánchez P. , Aroca C. , Prieto J. L.
Published: July 2009

The effect of inserting an ultrathin Gd layer (1–2 nm) in the free layer of a Permalloy-based spin valve has been investigated. In the current in-plane configuration, samples with Gd show a reduced magnetoresistance (MR) value, which tends to zero as Gd gets closer to the nonmagnetic spacer, although good MR values can be sustained when Gd is more than 5 nm away from the spacer. We studied also the effect of adding thin Fe layers around Gd in order to avoid Gd diffusion within the Permalloy. Samples with an Fe/Gd/Fe trilayer inserted in the free layer show some improvement at low temperatures over those without Fe, although the Fe introduces some detrimental additional roughness.
Phase resonances on metal gratings of identical, equally spaced alternately tapered slits
Authors: Rance Helen J. , Hamilton Oliver K. , Sambles J. Roy , Hibbins Alastair P.
Published: July 2009

Phase resonances are observed in the microwave response of metal transmission gratings comprised of identical but alternately orientated tapered slits. Despite each slit having identical dimensions, and being equally spaced from its neighbors, these high-Q mode are nonetheless supported even at normal incidence. The excitation of these modes is attributed to the interference between Fabry–Perot-like modes and diffractively coupled surface waves.
The influence of electrode erosion on the air arc in a low-voltage circuit breaker
Authors: Rong Mingzhe , Ma Qiang , Wu Yi , Xu Tiejun , Murphy Anthony B.
Published: July 2009

This paper focuses on the numerical research of the influence of electrode erosion on the arc behavior during opening process of low-voltage circuit breakers. The mathematical model of three-dimensional air arc plasma considering electrode erosion is built based on magnetic hydrodynamics. The mass fraction equation of copper vapor is introduced to the model on the basis of traditional mass, momentum, and energy balance equations. The influence of copper vapor on the thermodynamic and transport properties of the gas mixture is considered in this paper. The distributions of temperature field, gas flow field, and mass fraction of copper vapor in the arc chamber are simulated. The arc root displacements and arc voltage, which takes account of the influence of electrode erosion, are calculated. The simulation results indicate that the immobility time of both moving contact and stationary contact is much longer considering electrodes erosion. The calculated voltage of the arc column during arc motion considering erosion is smaller because of the change in the electrical conductivity of air-copper vapor mixtures. Except for the numerical investigation on the arc motion considering electrode erosion, the experiment work is also carried out to support the simulation work.
Galfenol alloying additions and the effects on uniaxial anisotropy generation
Authors: Summers Eric , Meloy Rob , Restorff J. B.
Published: July 2009

The effects of substitutional and interstitial additions on uniaxial anisotropy (Kuni) generated via stress annealing were investigated for the galfenol (Fe–Ga) alloy system. Polycrystalline samples prepared via free stand zone melt directional solidification technique were tested under pre- and post-stress annealed conditions in order to ascertain the extent of the built-in stress (Tbuilt-in) created. Energy based modeling utilizing magnetostriction and magnetization data was used to determine Kuni and Tbuilt-in. Differential magnetomechanical properties; d33 and μr were estimated using the same model. Carbon additions from a Fe–C master alloy resulted in Kuni and Tbuilt-in values of 12.1 kJ/m3 and 55 MPa, comparable to the binary system. Low carbon steel additions resulted in a minor decrease in Kuni to 9.6 kJ/m3, but still had high Tbuilt-in values of 54 MPa. Aluminum additions exhibited the largest decreases in Kuni and Tbuilt-in. A linear decrease in both values was observed as a function of increasing aluminum content. Kuni values for Fe81.6Ga13.8Al4.6 and Fe81.6Ga9.2Al9.2 alloys were 6.7 and 4.2 kJ/m3, respectively. Tbuilt-in values for Fe81.6Ga13.8Al4.6 and Fe81.6Ga9.2Al9.2 alloys were 37 and 24 MPa, respectively. Estimated d33 and μr values ranged from 2.0 to 2.7×10−8 m/A and 120–170 for all compositions studied.
Modeling ZnO phases using a periodic approach: From bulk to surface and beyond
Authors: Labat Frédéric , Ciofini Ilaria , Adamo Carlo
Published: July 2009

A comprehensive investigation of one of the basic components of ZnO-based dye-sensitized solar cells (DSSC) is presented, carried out using hybrid density functionals combined to a periodic formalism. Both semiconductor bulk and surfaces are discussed thoroughly, with a particular attention to structural and electronic aspects. Next, three possible adsorption modes of formic acid are compared and discussed at the same level of theory. The results confirm that formic acid appears as a suitable choice for an efficient anchoring of large organic molecules, such as the dyes commonly used for DSSC, to semiconductor surfaces since it allows both a stable adsorption and few but significant contributions to the density of states for all adsorption modes considered. More in general, our results suggest that hybrid functionals and, in particular the parameter free PBE0 (PBE denotes Perdew–Burke–Ernzerhof), can be considered as a reliable tool for modeling complex molecule-semiconductors interfaces such as the one of interest in DSSC, thus providing a powerful computational protocol for the in silico design of new systems for photovoltaic applications.
Transmission electron microscopy investigation of CoFeB/MgO/CoFeB pseudospin valves annealed at different temperatures
Authors: Karthik S. V. , Takahashi Y. K. , Ohkubo T. , Hono K. , Ikeda S. , Ohno H.
Published: July 2009

We have investigated the microstructure and local chemistry of Ta/Ru/Ta/CoFeB/MgO/CoFeB/Ta/Ru magnetic tunnel junctions with different values of tunneling magnetoresistance (TMR) as a result of annealing at different temperatures. Annealing at 500 °C led to the templated crystallization of the amorphous CoFeB layer having coherent interfaces with MgO grains with an orientation relationship of ⟨001⟩[011]MgO∥⟨001⟩[001]CoFe, and the B rejected from crystallized CoFeB was found to be dissolved in upper amorphous Ta layers and segregated in the bottom crystalline Ta layer. Annealing at 600 °C led to the dissolution of 3–4 at. % Ta in the MgO barrier, and B was found to be segregated at the CoFeB/MgO and Ta/Ru interfaces as a result of the crystallization of the top amorphous Ta layer. Further degradation in TMR of the samples annealed at 650 °C results from the loss of bcc-CoFe (001) texture in the bottom CoFeB electrode due to the pronounced Ta diffusion into the CoFe/MgO/CoFe layers.
Defect-engineered blue-violet electroluminescence from Ge nanocrystal rich SiO2 layers by Er doping
Authors: Kanjilal A. , Rebohle L. , Voelskow M. , Skorupa W. , Helm M.
Published: July 2009

Using combined microstructural and electroluminescence (EL) investigations of the Er-doped Ge-rich SiO2 layers, it is established that the Ge-related oxygen-deficiency centers (GeODCs), which are associated with the 407 nm light emission, are situated at the Ge nanocrystal/SiO2 interface. Electrically driven energy transfer from the Er3+ to GeODCs causes an increase in the 407 nm EL intensity. It reaches a maximum before quenching with increasing Er concentration due to the crystalline-to-amorphous transition of Ge nanocrystals. Ge concentration dependent quenching of the maximum EL intensity and the peak shifting toward higher Er concentration are discussed in terms of the reduction of the surface-to-volume ratio with increasing nanocrystal size.
Contribution of positive and negative ions to the electrohydrodynamic force in a dielectric barrier discharge plasma actuator operating in air
Authors: Boeuf J. P. , Lagmich Y. , Pitchford L. C.
Published: July 2009

We present a parametric study of the electrohydrodynamic force generated by surface dielectric barrier discharge plasma actuators in air for sinusoidal voltage waveforms. The simulation results confirm that momentum is transferred from the charged particles to the neutral species in the same direction during both positive and negative parts of the cycle. The momentum transfer is due to positive ions during the positive part of the cycle (electrode above the dielectric layer is the anode), and to negative ions during the negative part of the cycle. The relative contribution of the positive and negative parts of the cycle depends on the voltage amplitude and frequency. The model predicts that the contribution of negative ions tends to be dominant at low voltage frequencies and high voltage amplitudes.
Thermal strain-induced dielectric anisotropy in Ba0.7Sr0.3TiO3 thin films grown on silicon-based substrates
Authors: Zhu X. H. , Guigues B. , Defaÿ E. , Dubarry C. , Aïd M.
Published: July 2009

Dielectric properties of Ba0.7Sr0.3TiO3 (BST) thin films, which were prepared on silicon-based substrates by ion beam sputtering and postdeposition annealing method, were systematically investigated in different electrode configurations of metal-insulator-metal and coplanar interdigital capacitors. It was found that a large dielectric anisotropy exists in the films with better in-plane dielectric properties (higher dielectric permittivity and tunability) than those along the out-of-plane direction. The observed anisotropic dielectric responses are explained qualitatively in terms of a thermal strain effect that is related to dissimilar film strains along the in-plane and out-of-plane directions. Another reason for the dielectric anisotropy is due to different influences of the interfacial low-dielectric layer between the BST film and the substrate (metal electrode).
Temperature dependence of the energy transfer from amorphous silicon nitride to Er ions
Authors: Li R. , Yerci S. , Dal Negro L.
Published: July 2009

The 1.54 μm photoluminescence and decay time of Er-doped amorphous silicon nitride films with different Si concentrations are studied in the temperature range of 4 to 320 K. The temperature quenching of the Er emission lifetime demonstrates the presence of nonradiative trap centers due to excess Si in the films. The temperature dependence and the dynamics of the energy coupling between amorphous silicon nitride and Er ions are investigated at different temperatures using two independent methods, which demonstrate phonon-mediated energy coupling. These results can lead to the engineering of more efficient Er-doped, Si-based light sources for on-chip nanophotonics applications.
Windowed high-order ambiguity function method for fringe analysis
Authors: Gorthi Sai Siva , Rastogi Pramod
Published: July 2009

This paper introduces a windowed high-order ambiguity function (WHAF) method for the demodulation of fringe patterns recorded in holographic interferometry. It first obtains the analytic signal of the fringe pattern and models it as a piecewise polynomial phase signal. A parametric estimation procedure based on HAF is then employed to calculate the polynomial coefficients of the phase over each window of the segmented analytic signal. A salient feature of the proposed method is that it provides an accurate and direct estimation of the unwrapped phase distribution from a single fringe pattern, even when the pattern’s phase is rapidly varying. WHAF’s application to both digital and classical holographic interferometry is demonstrated by simulation and experimental results.