bluuebunny/crossref_metadata_2025 huggingface dataset:
Systematic changes in the incoming plate structure at the Kuril trench
Authors: Fujie Gou , Kodaira Shuichi , Yamashita Mikiya , Sato Takeshi , Takahashi Tsutomu , Takahashi Narumi
Published: December 2012

Recent seismic structural studies in trench‐outer rise regions have shown that Vp within the incoming oceanic plate systematically decreases toward the trench, probably owing to bending and fracturing of the plate. To understand the mechanisms acting to reduce Vp, Vs is critical because the Vp/Vs ratio is a sensitive indicator of lithology, porosity, and the presence of fluid. In the outer rise region of the Kuril trench, we conducted an extensive seismic refraction and reflection survey that revealed systematic changes in Vp, Vs, and Vp/Vs. Our results suggest that water content within the incoming oceanic plate increases toward the trench accompanied by the development of bending‐related fractures at the top of the oceanic crust, consistent with the seawater percolation. Our results support the idea that plate bending and fracturing during the bending in the outer rise of the trench play an important role in the water cycle of subduction zones.
Mirror mode structures in the asymmetric Hermean magnetosheath: Hybrid simulations
Authors: Herčík David , Trávníček Pavel M. , Johnson Jay R. , Kim Eun‐Hwa , Hellinger Petr
Published: December 2012

Results of two global three‐dimensional hybrid simulations of the solar wind interaction with the Hermean magnetosphere are presented for southward and northward interplanetary magnetic field (IMF) orientations. Important dawn‐dusk asymmetries of the Hermean bow shock and magnetosheath are observed depending on the IMF orientation. For the southward IMF, the dawnside has a thicker magnetosheath with higher β values and slower bulk velocities compared to the duskside, whereas for the northward IMF, the duskside has a thicker and higher β magnetosheath with slower bulk velocities. Mirror mode activity consequently appears at the dawnside for the southward IMF and at the duskside for the northward IMF. A mechanism for the bow shock and magnetosheath asymmetries is proposed and discussed in the context of the Hermean and terrestrial magnetosheaths.
Seasonal variation of surface and vertical profile of aerosol properties over a tropical urban station Hyderabad, India
Authors: Sinha P. R. , Manchanda R. K. , Kaskaoutis D. G. , Kumar Y. B. , Sreenivasan S.
Published: December 2012

One year measurement of vertical profiles of volume backscatter and extinction coefficient, aerosol optical depth (AOD), mass concentration of black carbon (BC) and composite aerosol along with thermodynamic structure of the atmosphere has been carried out over an urban tropical location of Hyderabad(17.47°N, 78.58°E), India, during April 2009 to March 2010. The mean mixing layer height (MLH) exhibits large seasonality exceeding 4 km in pre‐monsoon period whereas in winter it comes down to ~1.5 km with an annual mean value of 2.35 ± 1.02 km. Surface BC mass fraction (FBC) shows marked seasonal variation from winter (13 ± 1.9%), pre‐monsoon (8.19 ± 2.16%), monsoon (7.3 ± 1.8%) to post‐monsoon (11.8 ± 0.18%). The profiles of volume backscatter and extinction coefficients reveal presence of elevated aerosol layers from 2 to 4 km and strong oscillations during pre‐monsoon (March–May) and monsoon (June–September) seasons, respectively, while in post‐monsoon (October–November) and winter (December–February), the aerosols are well within the lower boundary layer and also exhibit a drastic decrease with increasing altitude. These elevated aerosol layers and vertical distribution appear to be closely linked to the thermodynamic structure of the atmosphere. The aerosol optical properties in conjunction with air mass back trajectory analysis indicate that the observed elevated aerosol layers during pre‐monsoon and monsoon could contain significant fraction of coarse mode particles with a mix of dust and marine aerosols. Further analysis reveals that the aerosols within atmospheric boundary layer (ABL) dominate the column aerosol loading with ABL‐AOD contributing to ~77.7 ± 17.0%, with significant seasonal variation from winter (86.2 ± 13.1%), pre‐monsoon (76.6 ± 12.8%), monsoon (54.2 ± 15.6%) to post monsoon (80.8 ± 14.8%). Seasonal variation of ABL‐AOD and BC mass fraction follows similar pattern in the ABL indicating that BC may be an important contributor to the ABL aerosol loading.
Evaluation of the atmospheric water vapor content in a regional climate model using ground‐based GPS measurements
Authors: Ning T. , Elgered G. , Willén U. , Johansson J. M.
Published: December 2012

Ground‐based GPS measurements can provide independent data for the assessment of climate models. We use the atmospheric integrated water vapor (IWV) obtained from GPS measurements at 99 European sites to evaluate the regional Rossby Centre Atmospheric climate model (RCA) driven at the boundaries by the European Centre for Medium‐Range Weather Forecasts (ECMWF) reanalysis data (ERA Interim). The GPS data were compared to the RCA simulation and the ERA Interim data. The comparison was first made using the monthly mean values. Averaged over the domain and the 14 years covered by the GPS data, IWV differences of about 0.47 kg/m2 and 0.39 kg/m2 are obtained for RCA‐GPS and ECMWF‐GPS, respectively. The RCA‐GPS standard deviation is 0.98 kg/m2 whereas it is 0.35 kg/m2 for the ECMWF‐GPS comparison. The IWV differences for RCA are positively correlated to the differences for ECMWF. However, this is not the case for two sites in Italy where a wet bias is seen for ECMWF, while a dry bias is seen for RCA, the latter being consistent with a cold temperature bias found for RCA in that region by other authors. Comparisons of the estimated diurnal cycle and the spatial structure function of the IWV were made between the GPS data and the RCA simulation. The RCA captures the geographical variation of the diurnal peak in the summer. Averaged over all sites, a peak at 17 local solar time is obtained from the GPS data while it appears later, at 18, in the RCA simulation. The spatial variation of the IWV obtained for an RCA run with a resolution of 11 km gives a better agreement with the GPS results than does the spatial variation from a 50 km resolution run.
Role of gravity waves in the forcing of quasi two‐day waves in the mesosphere: An observational study
Authors: Ern M. , Preusse P. , Kalisch S. , Kaufmann M. , Riese M.
Published: December 2012

Amplitudes of quasi two‐day waves (QTDWs) are derived from temperature observations of the High Resolution Dynamics Limb Sounder and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite instruments. In particular, a global climatology of QTDW amplitudes is derived from 10 years of SABER data, covering the mesosphere and lower thermosphere. This climatology is compared with geostrophic winds and climatologies of gravity wave (GW) momentum flux and GW drag absolute values derived from the same data set. We find that QTDWs are forced shortly after the maximum of the mesospheric summertime zonal wind jet in regions of jet instability where the meridional gradient of quasi‐geostrophic zonal mean potential vorticity is strongly negative. The jet instability regions are closely linked to enhanced GW drag that likely seeds those instabilities by decelerating the jet and causing the jet curvature responsible for the negative potential vorticity gradient. The vertical phase structure and the Eliassen‐Palm flux of the QTDWs are derived from SABER data and investigated. It is shown that QTDWs propagate upward starting from the jet instability regions. They exert eastward drag in the jet core, and strong westward drag at higher altitudes. Strikingly, the QTDWs are forced in regions where the global distribution of GWs exhibits a characteristic longitudinal structure caused by the GW source patterns in the summer hemisphere. This longitudinal structure might play an important role in the forcing of QTDWs; however, no clear link has been found to the observed QTDW zonal wavenumbers.
Characterization of methyl bromide and methyl chloride fluxes at temperate freshwater wetlands
Authors: Hardacre Catherine J. , Heal Mathew R.
Published: December 2012

Methyl bromide (CH3Br) and methyl chloride (CH3Cl) are important natural sources of halogens to the atmosphere. A total of 568 CH3Br and 418 CH3Cl net flux measurements were made for up to 2 years at the same locations within four different wetlands in Scotland. Mean (± 1 standard deviation (SD)) CH3Br and CH3Cl net fluxes across all measurements at each wetland were: Auchencorth Moss, 8 (± 7) and 3560 (± 1260) ng m–2 h–1; Old Castle Farm, 420 (± 70) and 500 (± 260) ng m–2 h–1; Red Moss of Balerno, 500 (± 90) and 140,000 (± 36,000) ng m–2 h–1; and St Margaret's Marsh, 3600 (± 600) and −270 (± 450) ng m–2 h–1. None of the wetlands was a large net sink. Where substantial emissions were observed, these followed seasonal trends, increasing early in the growing season and declining in early autumn. Some diurnal cycles were observed, with emissions greatest during the day, although lower emissions were present at night. None of the measured environmental parameters was a strong “universal” driver for fluxes, which were heterogeneous within and between the wetlands, and larger on average than reported to date; plant species appeared to be the dominant factor, the latter confirmed by vegetation removal experiments. Calluna vulgaris and Phragmites australis emitted particularly large amounts of CH3Br, the former also emitting substantial CH3Cl. While acknowledging the substantial uncertainties in extrapolating globally, observations from this work suggest that wetlands contribute more CH3Br and CH3Cl to the atmosphere than current World Meteorological Organization estimates.
Diagnosis of regime‐dependent cloud simulation errors in CMIP5 models using “A‐Train” satellite observations and reanalysis data
Authors: Su Hui , Jiang Jonathan H. , Zhai Chengxing , Perun Vince S. , Shen Janice T. , Del Genio Anthony , Nazarenko Larissa S. , Donner Leo J. , Horowitz Larry , Seman Charles , Morcrette Cyril , Petch Jon , Ringer Mark , Cole Jason , von Salzen Knut , d S. Mesquita Michel , Iversen Trond , Kristjansson Jon Egill , Gettelman Andrew , Rotstayn Leon , Jeffrey Stephen , Dufresne Jean‐Louis , Watanabe Masahiro , Kawai Hideaki , Koshiro Tsuyoshi , Wu Tongwen , Volodin Evgeny M. , L'Ecuyer Tristan , Teixeira Joao , Stephens Graeme L.
Published: December 2012

The vertical distributions of cloud water content (CWC) and cloud fraction (CF) over the tropical oceans, produced by 13 coupled atmosphere‐ocean models submitted to the Phase 5 of Coupled Model Intercomparison Project (CMIP5), are evaluated against CloudSat/CALIPSO observations as a function of large‐scale parameters. Available CALIPSO simulator CF outputs are also examined. A diagnostic framework is developed to decompose the cloud simulation errors into large‐scale errors, cloud parameterization errors and covariation errors. We find that the cloud parameterization errors contribute predominantly to the total errors for all models. The errors associated with large‐scale temperature and moisture structures are relatively greater than those associated with large‐scale midtropospheric vertical velocity and lower‐level divergence. All models capture the separation of deep and shallow clouds in distinct large‐scale regimes; however, the vertical structures of high/low clouds and their variations with large‐scale parameters differ significantly from the observations. The CWCs associated with deep convective clouds simulated in most models do not reach as high in altitude as observed, and their magnitudes are generally weaker than CloudSat total CWC, which includes the contribution of precipitating condensates, but are close to CloudSat nonprecipitating CWC. All models reproduce maximum CF associated with convective detrainment, but CALIPSO simulator CFs generally agree better with CloudSat/CALIPSO combined retrieval than the model CFs, especially in the midtroposphere. Model simulated low clouds tend to have little variation with large‐scale parameters except lower‐troposphere stability, while the observed low cloud CWC, CF, and cloud top height vary consistently in all large‐scale regimes.
A matter of life and death: self‐renewal in stem cells
Authors: Fuchs Elaine , Chen Ting
Published: December 2012

If Narcissus could have self‐renewed even once on seeing his own reflection, he would have died a happy man. Stem cells, on the other hand, have an enormous capacity for self‐renewal; in other words, the ability to replicate and generate more of the same. In adult organisms, stem cells reside in specialized niches within each tissue. They replenish tissue cells that are lost during normal homeostasis, and on injury they repair damaged tissue. The ability of a stem cell to self‐renew is governed by the dynamic interaction between the intrinsic proteins it expresses and the extrinsic signals that it receives from the niche microenvironment. Understanding the mechanisms governing when to proliferate and when to differentiate is vital, not only to normal stem cell biology, but also to ageing and cancer. This review focuses on elucidating conceptually, experimentally and mechanistically, our understanding of adult stem cell self‐renewal. We use skin as a paradigm for discussing many of the salient points about this process, but also draw on the knowledge gained from these and other adult stem cell systems to delineate shared underlying principles, as well as highlight mechanistic distinctions among adult tissue stem cells. By doing so, we pinpoint important questions that still await answers.
Caught in the act
Authors: Hunter Philip
Published: December 2012

Femtobiology freeze‐frames crucial split seconds of chemical reactions to investigate how enzymes function. The potential prize from this knowledge could be new avenues for drug development or ways to produce clean energy.
Tackling animal diseases to protect human health
Authors: Rinaldi Andrea
Published: December 2012

Veterinary research is gaining in importance not only because of the economic impact of animal diseases, but also because animals are a fertile reservoir of zoonoses; pathogens that could jump the species barrier and infect humans.
The promise and perils of Antarctic fishes
Authors: O'Brien Kristin M , Crockett Elizabeth L
Published: December 2012

The waters around the Antarctic are a treasure trove of fauna specially adapted to extreme cold temperatures. However, as with many other marine ecosystems, its life forms are threatened by human actions.
Different modes of IgE binding to CD23 revealed with major birch allergen, Bet v 1‐specific monoclonal IgE
Authors: Reginald Kavita , Eckl‐Dorna Julia , Zafred Domen , Focke‐Tejkl Margarete , Lupinek Christian , Niederberger Verena , Keller Walter , Valenta Rudolf
Published: December 2012

We investigated the binding of IgE and different types of allergen−IgE complexes to CD23‐expressing human B cells. We performed the experiments using chimeric Bip 1 (CB1), a chimeric humanized IgE specific for the major birch allergen, Bet v 1, together with monomeric and oligomeric forms of recombinant Bet v 1 (rBet v 1), and Bet v 1‐specific IgG antibodies. In this model IgE binding to CD23 was independent of variations in antibody affinities towards monomeric and oligomeric Bet v 1 as demonstrated by plasmon surface resonance. CB1 alone or in the form of small immune complexes consisting of one molecule of CB1 plus allergen, showed comparable binding to CD23 on B cells. Using anti‐IgE antibody probes discriminating CD23‐bound from CD23‐unbound IgE, it is demonstrated that in large immune complexes obtained with oligomeric Bet v 1 or by super‐crosslinking of small immune complexes with Bet v 1‐specific IgG, anti‐IgE staining of B cells increased. This increase of staining was due to the presence of IgE antibodies in the immune complexes that were not directly engaged in CD23 binding, and thus available for IgE detection. Our study thus reveals that CD23 can bind in a comparable manner to free IgE and IgE−allergen complexes of different size and composition, which may also include allergen‐specific IgG. The interplay of free IgE with IgE–allergen immune complexes of different sizes and composition with CD23 binding represents a mechanism for the modulation of CD23‐mediated immune responses such as IgE‐facilitated allergen presentation in allergic diseases.
Association of dietary sodium intake with atherogenesis in experimental diabetes and with cardiovascular disease in patients with Type 1 diabetes
Authors: Tikellis Chris , Pickering Raelene J. , Tsorotes Despina , Harjutsalo Valma , Thorn Lena , Ahola Aila , Wadén Johan , Tolonen Nina , Saraheimo Markku , Gordin Daniel , Forsblom Carol , Groop Per-Henrik , Cooper Mark E. , Moran John , Thomas Merlin C.
Published: December 2012

It is recommended that individuals with diabetes restrict their dietary sodium intake. However, although salt intake is correlated with BP (blood pressure), it also partly determines the activation state of the RAAS (renin–angiotensin–aldosterone system), a key mediator of diabetes-associated atherosclerosis. apoE KO (apolipoprotein E knockout) mice were allocated for the induction of diabetes with streptozotocin or citrate buffer (controls) and further randomized to isocaloric diets containing 0.05%, 0.3% or 3.1% sodium with or without the ACEi [ACE (angiotensin-converting enzyme) inhibitor] perindopril. After 6 weeks of study, plaque accumulation was quantified and markers of atherogenesis were assessed using RT–PCR (reverse transcription–PCR) and ELISA. The association of sodium intake and adverse cardiovascular and mortality outcomes were explored in 2648 adults with Type 1 diabetes without prior CVD (cardiovascular disease) from the FinnDiane study. A 0.05% sodium diet was associated with increased plaque accumulation in diabetic apoE KO mice, associated with activation of the RAAS. By contrast, a diet containing 3.1% sodium suppressed atherogenesis associated with suppression of the RAAS, with an efficacy comparable with ACE inhibition. In adults with Type 1 diabetes, low sodium intake was also associated with an increased risk of all-cause mortality and new-onset cardiovascular events. However, high sodium intake was also associated with adverse outcomes, leading to a J-shaped relationship overall. Although BP lowering is an important goal for the management of diabetes, off-target actions to activate the RAAS may contribute to an observed lack of protection from cardiovascular complications in patients with Type 1 diabetes with low sodium intake.
The Accuracy of Matching Target Insertion Gains With Open-Fit Hearing Aids
Authors: Aazh Hashir , Moore Brian C. J. , Prasher Deepak
Published: December 2012

Purpose

To assess the accuracy with which target insertion gains were matched for a single type of open-fit hearing aid, both on initial fitting and after adjustment.

Method

The hearing aids were fitted using the first-fit setting in the programming software and the target formula was selected as NAL–NL1. The difference between the real ear insertion gain (REIG) and the NAL–NL1 target REIG was recorded. The initial fitting was considered acceptable if the difference was less than 10 dB at all frequencies. If an initial fitting was not acceptable, the frequency-gain response was modified. The difference between the final REIG and the NAL–NL1 target REIG was recorded as final target mismatch.

Results

Of the 51 initial fittings, 36 (71%) failed to achieve a match within ±10 dB of the NAL–NL1 insertion gain target at 1 or more frequencies between 0.25 and 4 kHz. After the authors adjusted the frequency-gain response of the hearing aids, only 9 fittings (18%) failed to achieve a match.

Conclusion

These outcomes suggest that target insertion gains for the open-fit hearing aids used here are rarely achieved with a first fitting but can usually be achieved through adjustments based on REIG measurements.
Acceptable Noise Level and Psychophysical Masking
Authors: Rishiq Dania A. , Harkrider Ashley W. , Hedrick Mark S.
Published: December 2012

Purpose

Individuals with low acceptable noise levels (ANLs) accept more noise than individuals with high ANLs. To determine whether ANL is influenced more by afferent or efferent cortical responsiveness, the authors measured differences in temporal masking responses between individuals with low versus high ANLs. If listeners with low ANLs have masked thresholds similar to those of listeners with high ANLs, low ANLs may be due to reduced afferent responsiveness affecting both the masker and signal. If, however, listeners with low ANLs have masked thresholds better than that of listeners with high ANLs, there may be a physiological basis for improved selective attention via stronger efferent inhibition of the “unwanted” sound.

Method

Participants were 19 listeners with normal hearing between the ages of 19 and 35. Ten listeners had low ANLs and 9 had high ANLs. All participants were compared using tone-in-noise simultaneous, forward, and backward masking tasks.

Results

Results revealed no observed differences in masked thresholds between the low versus high ANL group. The low ANL group, however, required significantly more threshold runs to achieve criterion necessary for threshold determinations.

Conclusions

Findings suggest that low ANLs are associated with reduced afferent cortical responsiveness and, possibly, decreased sustained attention.
Effects of Advancing Age and Hearing Loss on Gaps-in-Noise Test Performance
Authors: John Andrew B. , Hall James W. , Kreisman Brian M.
Published: December 2012

Purpose

The present study evaluated the effects of advancing age and sensorineural hearing loss (SNHL) on approximate temporal gap detection thresholds obtained from the Gaps-in-Noise (GIN; Musiek et al., 2005) test.

Method

Approximate thresholds from the GIN test were compared among 3 groups of participants (older adults with SNHL, older adults with essentially normal hearing, and young adults with normal hearing). Analyses of variance and regression modeling were used to determine the effect of age and audibility on GIN performance. Comparisons of thresholds obtained from the 4 test lists of the GIN were also conducted.

Results

Approximate gap thresholds differed significantly across all groups, with the poorest thresholds found in older adults with SNHL and with the best thresholds found in young adults with normal hearing. The strongest predictor of decreases in GIN performance was increased Audibility Index score, but a significant independent effect of age was also documented. Test list influenced GIN performance only in the group of young adults with normal hearing.

Conclusions

The GIN test is a promising clinical measure of temporal resolution. Findings from the present study suggest that age and audibility influence GIN performance and may affect test analysis and interpretation with published normative data.
Determining the Presence or Absence of Middle Ear Disorders: An Evidence-Based Systematic Review on the Diagnostic Accuracy of Selected Assessment Instruments
Authors: Sanford Chris A. , Schooling Tracy , Frymark Tobi
Published: December 2012

Purpose

To conduct an evidence-based systematic review on the state of the evidence and the diagnostic accuracy of multifrequency tympanometry (MFT), 1000 Hz tympanometry, and wideband acoustic transfer functions in determining the presence or absence of middle ear disorders.

Method

A systematic search of the literature published between 1975 and 2011 was conducted. Articles meeting the selection criteria were appraised by 2 reviewers and vetted by a 3rd for methodological quality.

Results

Ten studies were included and focused on participants with otosclerosis or otitis media. Two studies investigated 1000 Hz tympanometry, 7 examined MFT, and 2 addressed wideband reflectance (WBR). Methodological quality varied. Positive likelihood ratios (LR+) were predominantly uninformative for MFT and were mixed for 1000 Hz tympanometry. LR+ values for WBR ranged from diagnostically suggestive to informative. Negative likelihood ratios (LR−) for 1000 Hz tympanometry and WBR were at least diagnostically suggestive. LR− values for MFT were mixed, with half considered clinically uninformative and half considered diagnostically suggestive.

Conclusions

Although some of the results are promising, limited evidence and methodological considerations restrict the conclusions that can be drawn regarding the diagnostic accuracy of these technologies. Additional investigations are needed to determine which tools can most accurately predict middle ear status.
Audiologists' Professional Satisfaction
Authors: Saccone Patricia , Steiger James
Published: December 2012

Purpose

The authors surveyed currently practicing audiologists to evaluate their professional satisfaction and compared the results to a similar survey conducted in 1997.

Method

The authors repeated an audiologist professional satisfaction survey conducted in 1997; 382 randomly chosen, currently practicing audiologists participated. Responses to 38 statements were on a 5-point Likert scale (5 =
strong agreement with a statement,
1 =
strong disagreement with a statement
). The respondent sample was broken down into demographic subgroups, and statements were divided into subgroups reflecting 6 core reward areas that contribute to overall professional satisfaction.

Results

Mean group satisfaction was 3.9 (
n
= 382;
SD
= 1.01), which has remained unchanged since 1997 (
p
< .05). Private practice audiologists' mean group satisfaction of 4.31 (
n
= 80,
SD
= 0.78) was higher than for other practice settings (
p
< .05). AuD private practice owners' mean group satisfaction of 4.52 (
n
= 46,
SD
= 0.66) was higher than for other degrees and practice settings (
p
< .05). Core reward area ratings differed for AuD, MA/MS, and PhD degree holders (
p
< .05). Correlations between the average core reward area ratings and mean group satisfaction met statistical significance (
p
< .05).

Conclusions

These results have implications for goal setting and planning within the profession and for audiologists' career choices.
Suppression of the Vestibulo-Ocular Reflex Using Visual and Nonvisual Stimuli
Authors: Jacobson Gary P. , Piker Erin G. , Do Christina , McCaslin Devin L. , Hood Linda
Published: December 2012

Purpose

To determine to what extent attention directed toward visual, auditory, somesthetic, and imaginary sources would attenuate the vestibulo-ocular reflex (VOR).

Method

Two prospective studies included 16 (Investigation 1) and 5 (Investigation 2) healthy participants (mean age of 24 years in Investigation 1 and 37 years in Investigation 2). VOR gain was assessed with a commercially available rotary chair and was measured in dark both while the subject was tasked with mental alerting exercises and while not being tasked. VOR suppression was measured for the following conditions: (a) visual suppression, (b) auditory suppression, (c) somatosensory suppression, (d) imaginary visual target suppression, and (e) combined auditory and somatosensory suppression.

Results

Attention directed to visual source attenuated the VOR by approximately 85%. Attention directed toward auditory and somatosensory targets (both separately and combined) and attention directed toward an imaginary target suppressed the VOR between 28% and 44%. The extent of VOR suppression that occurred with attention directed toward various nonvisual stimuli was significantly less than the visual suppression of the VOR. The various nonvisual conditions were not statistically different from one another.

Conclusion

The data suggest that it is possible for typical adults to suppress the VOR in the absence of a visual target. That is, the VOR can be attenuated with attention directed toward chair-fixed visual, auditory, somatosensory, and imaginary targets.
Older Adults and Hearing Help-Seeking Behaviors
Authors: Saunders Gabrielle H. , Chisolm Theresa H. , Wallhagen Margaret I.
Published: December 2012

Purpose

To review the current literature on help seeking for hearing health care among older adults.

Method

The authors conducted a literature review regarding help seeking for hearing-related communication difficulties as well as for other chronic medical conditions.

Results

Untreated hearing loss can lead to numerous negative secondary consequences; uptake and use of hearing aids remain low, despite the fact that hearing aids provide an effective treatment option for older adults with hearing loss. The authors describe models relevant to understanding the help-seeking and decision-making behaviors of older adults with hearing loss and discuss recommendations for future research.

Conclusion

Because of the considerable overlap in factors associated with help-seeking behaviors across chronic medical conditions and because help-seeking behaviors are complex, help seeking should be examined within the framework of a multifactorial model, such as the health belief model or the transtheoretical stages of change model.
The Effects of Aging on Auditory Processing and Cognition
Authors: Tun Patricia A. , Williams Victoria A. , Small Brent J. , Hafter Ervin R.
Published: December 2012

Purpose

To briefly summarize existing data on effects of aging on auditory processing and cognition.

Method

A narrative review summarized previously reported data on age-related changes in auditory processing and in cognitive processes with a focus on spoken language comprehension and memory. In addition, recent data on effects of lifestyle engagement on cognitive processes are reviewed.

Results

There is substantial evidence for age-related declines in both auditory processes and cognitive abilities. Accumulating evidence supports the idea that the perceptual burden associated with hearing loss impacts the processing resources available for good comprehension and memory for spoken language, particularly in older adults with limited resources. However, many language abilities are well preserved in old age, and there is considerable variability among individuals in cognitive performance across the life span. The authors discuss how lifestyle factors and socioemotional engagement can help to offset declining abilities.

Conclusions

It is clear that spoken language processing in adulthood and old age is affected by changes in perceptual, cognitive, and socioemotional processes as well as by interactions among these changes. Recommendations for further research include studying speech comprehension in complex conditions, including meaningful-connection spoken language, and tailoring clinical interventions based on patients' auditory processing and cognitive abilities along with their individual socioemotional demands.
An Introduction to the Second Starkey Research Summit
Authors: Abrams Harvey B.
Published: December 2012

Purpose

In the coming decades, Americans with hearing and cognitive deficits will represent a growing proportion of the population. This article describes the rationale and goals of the second Starkey Research Summit, which was convened to better understand the challenges that an aging demographic represents to the future of hearing health care.

Method

A multidisciplinary group of scientists representing audiology, cognitive science, psychology, aging, and hearing science met in the fall of 2011 to explore key issues associated with the convergence of aging, hearing loss, and cognitive deficit.

Results

Four major topic areas were identified for discussion and further exploration: (a) the effects of aging on auditory processing and cognition; (b) the effects of hearing technology on auditory processing and cognition in the elderly; (c) the effects of training on auditory processing and cognition in the elderly; and (d) the effects of aging on hearing help-seeking behavior.

Conclusion

A brief overview of each of the four major topic areas, to include the identification of unmet research needs, was prepared and is included in this issue of the
American Journal of Audiology.
Imaging the O(1D) + CD4 → OD + CD3 reaction dynamics: Probing vibrationally and rotationally excited CD3 products
Authors: Shuai Quan , Pan Huilin , Yang Jiayue , Zhang Dong , Jiang Bo , Dai Dongxu , Yang Xueming
Published: December 2012

The dynamics of the O(1D) + CD4 → OD + CD3 reaction has been studied using the crossed molecular beam technique with sliced velocity map imaging. Internally excited CD3 products were detected using a (2+1) resonance-enhanced multiphoton ionization with state resolution. Dual reaction mechanisms, insertion and abstraction, were only observed for CD3 products with its umbrella mode (v2) excited or in its ground state, while CD3 products with other vibrational mode excited do not show any evidence of contributions from the abstraction pathway. Experimental results indicate that even though the insertion channel dominates the reaction, the abstraction channel contributes relatively more to vibrationally excited CD3 products. The state-to-state correlation between the two reaction products, OD and CD3, was determined for the abstraction channel at different collision energies. In addition, we measured rotationally hot CD3 products and found that these products are only produced via the insertion channel.
An oppositely charged insect exclusion screen with gap-free multiple electric fields
Authors: Matsuda Yoshinori , Kakutani Koji , Nonomura Teruo , Kimbara Junji , Kusakari Shin-ichi , Osamura Kazumi , Toyoda Hideyoshi
Published: December 2012

An electric field screen was constructed to examine insect attraction mechanisms in multiple electric fields generated inside the screen. The screen consisted of two parallel insulated conductor wires (ICWs) charged with equal but opposite voltages and two separate grounded nets connected to each other and placed on each side of the ICW layer. Insects released inside the fields were charged either positively or negatively as a result of electricity flow from or to the insect, respectively. The force generated between the charged insects and opposite ICW charges was sufficient to capture all insects.
Using scattering theory to compute invariant manifolds and numerical results for the laser-driven Hénon-Heiles system
Authors: Blazevski Daniel , Franklin Jennifer
Published: December 2012

Scattering theory is a convenient way to describe systems that are subject to time-dependent perturbations which are localized in time. Using scattering theory, one can compute time-dependent invariant objects for the perturbed system knowing the invariant objects of the unperturbed system. In this paper, we use scattering theory to give numerical computations of invariant manifolds appearing in laser-driven reactions. In this setting, invariant manifolds separate regions of phase space that lead to different outcomes of the reaction and can be used to compute reaction rates.
Evidence of metastability near the Curie temperature of polycrystalline gadolinium
Authors: Seyoum Hailemichael M. , Ghahremani Mohammadreza , ElBidweihy Hatem , Bennett Lawrence H. , Della Torre Edward
Published: December 2012

The adiabatic temperature change (ΔT) during the magnetization and demagnetization processes of bulk gadolinium is directly measured for several applied magnetic fields in the temperature range 285 K to 305 K. In low magnetic fields, the measurements of ΔT display two maxima at 293.8 K and 291.5 K with an inflection point between 289 K and 293 K. The height of the second peak is more pronounced at low applied magnetic fields and diminishes in high fields. The occurrence of a second ΔT maximum is indicative of the complex spin dynamics in Gd and is related to the presence of metastable states near the Curie temperature.
Communication: Tensor hypercontraction. III. Least-squares tensor hypercontraction for the determination of correlated wavefunctions
Authors: Hohenstein Edward G. , Parrish Robert M. , Sherrill C. David , Martínez Todd J.
Published: December 2012

The manipulation of the rank-four tensor of double excitation amplitudes represents a challenge to the efficient implementation of many electronic structure methods. We present a proof of concept for the approximation of doubles amplitudes in the tensor hypercontraction (THC) representation. In particular, we show how THC can be used to both reduce the scaling with respect to molecular size of coupled cluster singles and doubles (CCSD) (and related methods) by two orders [from O(N6) to O(N4)] and remove the memory bottleneck associated with storage of the doubles amplitudes. The accuracy of correlated methods as integral and amplitude approximations are introduced is examined. For a set of 20 small molecules, single and double-excitation configuration interaction (CISD), quadratic CISD (QCISD), and CCSD correlation energies could be reproduced with millihartree accuracy after the introduction of these approximations. Our approach exploits otherwise hidden factorizable tensor structure in both the electron repulsion integrals and the wavefunction coefficients and should be applicable with suitable modifications to many methods in electronic structure theory.
Size dependence of the Curie temperature of L1o-FePt nanoparticles
Authors: Lyberatos A. , Weller D. , Parker G. J. , Stipe B. C.
Published: December 2012

Monte Carlo simulations using the single histogram method are performed to study the effects of finite size and Cu doping on the Curie temperature of a single FePt nanoparticle. An atomistic model is used with an effective classical spin Hamiltonian constructed on the basis of first-principles calculations for L1o FePt. The Curie temperature, evaluated from the peak in the temperature variation of the magnetic susceptibility, is consistent with the finite-size scaling relation Tc(L)=Tc(∞)(1−xoL−1/ν), where L is the in-plane grain size, xo is found to depend on the grain aspect ratio, and the critical exponent of the correlation length is ν=1.06±0.06. A theoretical relation is obtained for the Tc dispersion arising from a lognormal grain size distribution. Addition of Cu results in reduction of the Curie temperature proportional to the dopant content.
Magnetic resonance imaging using linear magneto-inductive waveguides
Authors: Syms R. R. A. , Young I. R. , Ahmad M. M. , Rea M.
Published: December 2012

Magneto-inductive waveguides are arrays of magnetically coupled, lumped element resonators, which support slow waves at radio frequency. Their use in internal magnetic resonance imaging (MRI), where they may provide an intrinsically safe method of signal detection and transmission, is described. A catheter-based receiver formed from a thin-film printed circuit mounted on a tubular scaffold using heat-shrink tubing is demonstrated, and its electrical response and imaging sensitivity are explained in terms of the excitation and propagation of magneto-inductive waves. The theoretical predictions are confirmed using the results of electrical measurement and 1H MRI at 1.5 T, and imaging is achieved over a total length greater than 1.5 m using a single receiver.
Effects of the internal structure of spheroidal divalent ions on the charge density profiles of the electric double layer
Authors: Guadalupe Ibarra-Armenta José , Martín-Molina Alberto , Bohinc Klemen , Quesada-Pérez Manuel
Published: December 2012

In this work, the effects of the internal structure of charge for ions are analyzed by means of Monte Carlo simulations within a modified primitive model of electric double layer with spheroidal ions. The simulation results are compared to those obtained from a generalized Poisson-Boltzmann theory, where the separation of the charges within the spheroidal ions is considered. The spheroidal divalent ions have finite dimensions and two identical unitary charges separated by a distance of one diameter. Two structurally equivalent but oppositely charged ionic species are considered: coions and counterions. In the simulation, the number of particles is not fixed and the grand canonical ensemble is employed to reach the thermodynamic equilibrium. Meanwhile, the variational theory is applied to the analytical density functional. The fixed separation between charges within the spheroidal ions causes the orientational ordering of the spheroidal ions (with quadrupolar charge distributions) leading to very different charge distributions than those of the regular divalent ions from the primitive model of electrolyte. The internal structure of ions could be dramatically relevant for the modelling of large molecules, which are known to posses complex charge distributions.
Time-resolved spin-dependent processes in magnetic field effects in organic semiconductors
Authors: Peng Qiming , Li Xianjie , Li Feng
Published: December 2012

We investigated the time-resolved magnetic field effects (MFEs) in tri-(8-hydroxyquinoline)-aluminum (Alq3) based organic light-emitting diodes (OLEDs) through the transient electroluminescence (EL) method. The values of magneto-electroluminescence (MEL) decrease with the time, and the decreasing slope is proportional to the driving voltage. Specifically, negative MELs are seen when the driving voltage is high enough (V > 11 V). We propose a model to elucidate the spin-dependent processes and theoretically simulate the time-resolved MELs. In particular, this dynamic analysis of time-resolved MELs reveals that the intersystem crossing between singlet and triplet electron-hole pairs and the triplet-triplet annihilation are responsible for the time-resolved MELs at the beginning and enduring periods of the pulse, respectively.
Permanent recovery of electron lifetime in pre-annealed silicon samples: A model based on Ostwald ripening
Authors: Voronkov V. V. , Falster R. , Lim B. , Schmidt J.
Published: December 2012

The permanent deactivation of the boron-oxygen-related recombination centre in crystalline silicon was previously found to slow down after pre-annealing at 450 °C. In this study, the impact of pre-annealing at 450 °C and 475 °C on the permanent deactivation process is studied in more detail, revealing that the rate constant is fundamentally reduced. We explain this finding by ascribing the deactivation effect to sinking of interstitial boron atoms (Bi) to boron nano-precipitates. A pre-anneal will result in Ostwald ripening of nano-precipitates and hence to an essential reduction in their sinking efficiency RpNp, where Np is the density and Rp is the average radius. By simulations it was found that (RpNp)−3/2 is a linear function of the annealing time—insensitive to the starting size distribution. This linear law well corresponds to the measured variation in the rate constant. In addition, it was concluded that the major traps for Bi (under illumination) are defect complexes BsO2—of substitutional boron and oxygen.
On the density of states of germanium telluride
Authors: Longeaud C. , Luckas J. , Krebs D. , Carius R. , Klomfass J. , Wuttig M.
Published: December 2012

Germanium telluride (GeTe) is one of the most studied phase change materials. Surprisingly, only little is known about the density of states (DOS) in its band gap. In this paper, the DOS of amorphous GeTe films is investigated both experimentally and theoretically. We propose a model for this DOS as well as estimates of some of the transport parameters of this material. Thin films of amorphous GeTe have been deposited by sputtering. Their dark and photoconductivity have been measured as a function of temperature. By means of the modulated photocurrent technique their DOS was probed, while their absorption was investigated by photothermal deflection spectroscopy at room temperature. Numerical calculations were employed to reproduce the experimental results with a proper set of transport parameters and choice of DOS. These data constitute a good basis for further study on the influence of the DOS on the aging of the sample resistance (“resistance drift”).
High-harmonic transient grating spectroscopy of NO2 electronic relaxation
Authors: Ruf H. , Handschin C. , Ferré A. , Thiré N. , Bertrand J. B. , Bonnet L. , Cireasa R. , Constant E. , Corkum P. B. , Descamps D. , Fabre B. , Larregaray P. , Mével E. , Petit S. , Pons B. , Staedter D. , Wörner H. J. , Villeneuve D. M. , Mairesse Y. , Halvick P. , Blanchet V.
Published: December 2012

We study theoretically and experimentally the electronic relaxation of NO2 molecules excited by absorption of one ∼400 nm pump photon. Semiclassical simulations based on trajectory surface hopping calculations are performed. They predict fast oscillations of the electronic character around the intersection of the ground and first excited diabatic states. An experiment based on high-order harmonic transient grating spectroscopy reveals dynamics occurring on the same time scale. A systematic study of the detected transient is conducted to investigate the possible influence of the pump intensity, pump wavelength, and rotational temperature of the molecules. The quantitative agreement between measured and predicted dynamics shows that, in NO2, high harmonic transient grating spectroscopy encodes vibrational dynamics underlying the electronic relaxation.
Spacer-less, decoupled granular L1 FePt magnetic media using Ar–He sputtering gas
Authors: Kundu Shreya , Gaur Nikita , Saifullah M. S. M. , Yang Hyunsoo , Bhatia Charanjit S.
Published: December 2012

Spacer materials are often used to fabricate granular L10 FePt media and reduce the grain size, however, at the expense of reduced out-of-plane coercivity. Here, we demonstrate a spacer-less method in which adding 1% helium to argon sputtering gas leads to a substantial improvement in the chemical ordering, as well as the magnetic and microstructural properties of FePt. This change is attributed to the modification in the ion current density of the plasma caused by the excited metastable helium species. Helium plays a pivotal role in providing the Fe and Pt atoms optimal adatom mobility, thereby, producing well-ordered L10 FePt media. This leads to an enhancement of the out-of-plane coercivity from 15 to 22 kOe. Furthermore, exchange decoupled grains with a twofold reduction in their diameter to ∼24 nm are also achieved. These properties are crucial for magnetic media of the future for data storage recording densities beyond 1 Tb/in2.
Ab initiostudy of the influence of structural parameters on the potential energy surfaces of spin-crossover Fe(II) model compounds
Authors: Boilleau Corentin , Suaud Nicolas , Guihéry Nathalie
Published: December 2012

In spin-crossover (SCO) compounds exhibiting a light induced excited spin state trapping (LIESST) effect, the thermodynamic T1/2 and kinetic T(LIESST) temperature values depend on the features of the potential energy surfaces (PES) of the two lowest singlet and quintet states but also on vibrational contributions, collective effects, such as electrostatics, for instance, spin-orbit couplings to a lesser extent, etc. In this work, the question of the link between the shape of the PES of SCO compounds exhibiting a LIESST effect and their first coordination sphere structure is addressed from wave function theory based ab initio calculations. Fe(II) complexes based on model ligands suited to reproduce the main characteristics of the PES of such compounds are distorted to emphasize selectively the role played by the metal-ligand distances and the ligand-metal-ligand angles. The studied angular deformations are those usually observed in many Fe(L)2(NCS)2 complexes. It is shown that the larger the deformation between the low spin and high spin equilibrium geometries, the higher the energy barrier from the high spin state and the weaker the energy difference between the bottom of the wells. These results corroborate observations made by experimentalists on a large number of complexes. While the PES features only constitutes one of the contributions to these temperatures, it is worth noticing that, relating T1/2 to the energy difference between the bottoms of the singlet and quintet wells and the T(LIESST) to the energy barrier from the quintet bottom well, the same slope of the empirical law T(LIESST) = −0.3T1/2+T0 is observed.