bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutrition in Colombian pregnant women
Authors: Sarmiento Olga L , Ramirez Andrea , Kutschbach Belén Samper , Pinzón Paula L , García Sandra , Olarte Angie C , Mosquera Tatiana , Atalah Eduardo , Ojeda Gabriel , Forero Yibby
Published: January 2012

Objective

The present study aimed to evaluate the nutritional status of pregnant women in Colombia and the associations between gestational BMI and sociodemographic and gestational characteristics.

Design

Cross-sectional study. A secondary analysis was made of data from the 2005 Demographic and Health Survey of Colombia.

Setting

Bogotá, Colombia.

Subjects

Pregnant adolescents aged 13–19 years (n 430) and pregnant women aged 20–49 years (n 1272).

Results

The gestational BMI and sociodemographic characteristics of the adolescents differed from those of the pregnant adult women. Thirty-one per cent of the adolescents were underweight for gestational age, compared with 14·5 % of the adult women. Eighteen per cent of adolescents were overweight for gestational age, in contrast to 37·3 % of adult women. The overall prevalence of anaemia was 44·7 % and the prevalence of low serum ferritin was 38·8 %. Women within the high quintiles of the wealth index (prevalence odds ratio (POR) = 0·56; 95 % CI 0·34, 0·91, P < 0·02) had lower odds of being underweight. Women who received prenatal care (POR = 2·17; 95 % CI 1·48, 3·09, P < 0·001) and were multiparous (POR = 2·10; 95 % CI 1·43, 3·15, P < 0·0 0 1) had higher odds of being overweight. Women in extended families (POR = 0·63; 95 % CI 0·50, 0·95, P < 0·025) had lower odds of being overweight.

Conclusions

Underweight in pregnant adolescents and overweight in adult women coexist as a double burden in Colombia. Factors associated with malnutrition among pregnant women and adolescents should be considered for future interventions in countries experiencing nutritional transition.
Overlapping Institutions in Trade Policy
Authors: Davis Christina L.
Published: January 2012

This article examines the effect of overlapping institutions in trade policy, where the World Trade Organization, preferential trade agreements, and other economic negotiation venues give states many options for negotiating rules and settling disputes. This article argues that overlapping institutions influence trade politics at three stages: selection of venue, negotiation of liberalization commitments, and enforcement of compliance. First, lobby groups and governments on both sides of a trade negotiation try to choose the set of rules that will favor their preferred outcome. WTO rules that restrict use of coercive tactics outside of the WTO generate a selection process that filters the most difficult trade issues into WTO trade rounds or dispute adjudication while easier issues are settled in bilateral and regional fora. This selection dynamic creates a challenge at the negotiation stage by disaggregating interest group pressure for liberalization commitments. The narrowing of interest group lobbying for the multilateral process may impede negotiation of liberalization agreements that could only gain political support through a broad coalition of exporter mobilization. At the enforcement stage international regime complexity creates the potential for contradictory legal rulings that undermine compliance, but also adds greater penalties for noncompliance if reputation effects operate across agreements.
Response to Ioannis D. Evrigenis's review of Ruling Oneself Out: A Theory of Collective Abdications
Authors: Ermakoff Ivan
Published: January 2012

In a book written more than four hundred years ago (Discourse on Voluntary Servitude, 1548), La Boétie conveyed his astonishment about people “acquiescing to their own servitude.” Ruling Oneself Out restates the problem: why do groups legitimize the prospect of their political incapacity and, by way of consequence, the possibility of their servitude? I address this question by considering two parliamentary decisions of crucial historical significance: the parliamentary surrenders of constitutional authority in Germany (March 1933) and in France (July 1940). These events have paradigmatic value because they are clear-cut cases of collective abdications and because they lend themselves to explanations that seem as obvious as they are commonsensical. People abdicate because they face coercive pressures. They abdicate because they misjudge the consequences of their action. Or they abdicate because their ideology predisposes them to do so.
The narrative epidemiology of L'Aquila 2009 earthquake
Authors: Casacchia M. , Pollice R. , Roncone R.
Published: January 2012

The authors describe their experience working and living in L'Aquila, where at 3.32 a.m., early in the morning of 6 April 2009, a 6.3 Richter magnitude earthquake caused serious damages to this 13th century town (with a population of 72 000 and a health district of 103 788), in the mountainous Abruzzo region and to several medieval hill villages in the surrounding areas: 309 residents were killed, over 1600 were injured, 66 000 residents were displaced, and, the centre of L'Aquila, the main historical and artistic centre of Abruzzo, was totally destroyed.

Here is described the work done at the Psychiatric Unit of the General Hospital of L'Aquila and in the University. The Authors report the incidence rate of Acute Stress Disorder (ASD) in help-seekers (full ASD 4.9%, and partial ASD 39.3%), and of post-traumatic stress disorder (PTSD) found in different samples of population (range 12–37.5). The authors express their consideration about which real-world variables can reflect the population distress and the naturalistic process of recovery in such natural disasters. After the earthquake they hypothesize that a lot of residents had found their way to recover through ‘writing, telling the story’, by analogy with what narrative medicine asserts, thus estimating the positive effect of ‘emotional disclosure’ on health. A large number of materials (books, web-blogs, videos) were produced by residents and a database of memories was implemented. The suffering and struggle to recover in the aftermaths of a traumatic experience often yields remarkable transformations and positive growth. From this point of view, the authors underline the increased virtual relationships of residents through Facebook, to cope with the loss of previous social relationships, to get information about recreational opportunities, or to get organized for public events, despite their displacement. Many collective demonstrations were organized and showed the will to actively participate to the processes of reconstruction of the civil and scientific life of the town. The authors stress the need to prevent natural disasters, instead of preventing mental disorders following natural disasters, reporting that seven Italian seismologists and scientists are on trial for manslaughter, accused to have failed to evaluate the true risks of L'Aquila earthquake.
The annual and longitudinal variations in plasmaspheric ion density
Authors: Menk F. W. , Ables S. T. , Grew R. S. , Clilverd M. A. , Sandel B. R.
Published: January 2012

This paper shows that at solar maximum, equatorial ion densities at L = 2.5 are substantially higher at American longitudes in the December months than in the June months. This arises because the configuration of the geomagnetic field causes a longitude‐dependent asymmetry in ionospheric solar illumination at conjugate points that is greatest at American longitudes. For example, at −60°E geographic longitude the L = 2.5 field line has its foot point near 65° geographic latitude in the Southern Hemisphere but near 42° latitude in the Northern Hemisphere. We investigated the consequent effects on equatorial electron and ion densities by comparing ground‐based observations of ULF field line eigenoscillations with in situ measurements of electron densities (from the CRRES and IMAGE spacecraft) and He+ densities (IMAGE) for L = 2.5 at solar maximum. Near −60°E longitude the electron and ion mass densities are about 1.5 and 2.2 times larger, respectively, in the December months than in the June months. Over the Asia‐Pacific region there is little difference between summer and winter densities. Plasmaspheric empirical density models should be modified accordingly. By comparing the electron, helium, and mass densities, we estimate the annual variation in H+, He+, and O+ concentrations near −3°E longitude and −74°E longitude. In each case the He+ concentration is about 5% by number, but O+ concentrations are substantially higher at −3°E longitude compared with −74° E. We speculate that this may be related to enhanced ionospheric temperatures associated with the South Atlantic anomaly.
Lithospheric strength and strain localization in continental extension from observations of the East African Rift
Authors: Kogan L. , Fisseha S. , Bendick R. , Reilinger R. , McClusky S. , King R. , Solomon T.
Published: January 2012

GPS observations along three profiles across the Ethiopian Rift and Afar triple junction record differences in the length scale over which extension is accommodated. In the Afar region, where the mantle lithosphere is nearly or entirely absent, measurable extension occurs over ∼175 km; in the northern Ethiopian Rift, where the mantle lithosphere is anomalously thin and hot, extensional strain occurs over ∼85 km, extending beyond the structural rift valley; in the southern Ethiopian Rift, where the mantle lithosphere approaches standard continental thickness, extensional strain occurs over <10 km. This trend of increasingly distributed deformation contrasts with the standard model where continental rifts become mid‐ocean spreading centers through strain localization.
Toward quantifying uncertainty in travel time tomography using the null‐space shuttle
Authors: de Wit R. W. L. , Trampert J. , van der Hilst R. D.
Published: January 2012

The solution of large linear tomographic inverse problems is fundamentally non‐unique. We suggest to explore the non‐uniqueness explicitly by examining the null‐space of the forward operator. We show that with the null‐space shuttle it is possible to assess robustness in tomographic models, and we illustrate the concept for the global P‐wave model MIT‐P08. We found a broad range of acceptable solutions compatible with the travel time data. The root mean square (RMS) velocity perturbations vary from 0.2 to 0.6% in the lowermost mantle and from 0.3 to 1.3% in the upper mantle. Such large variations in average amplitudes prohibit meaningful inferences on temperature or chemical variations in the Earth from tomographic models alone. On a global scale much short wavelength structure resides in the null‐space of the forward operator, suggesting that the data do not everywhere resolve structure on the smallest length scale (<200 km) allowed by the (block) parameterization used in MIT‐P08 and similar models. This indicates that great care should be taken when interpreting such structure. As a practical measure, we suggest that only those structures for which the wave speed perturbations do not change sign within the range of models permitted by the data should be considered robust. With this criterion, the model null‐space analysis shows that the high velocity anomalies in the lower mantle, which are often interpreted as remnants of slabs of subducted lithosphere, are required by the seismic data. Low‐velocity anomalies underneath, for instance, Hawaii, Iceland, and Africa show varying degrees of robustness.
Variety and spatial heterogeneity of tectonic tremor worldwide
Authors: Ide Satoshi
Published: January 2012

Deep tectonic tremor occurs at various sites worldwide, and the source characteristics are heterogeneous, even at small scales. In this study, tremor sources were determined using data sets of seismic waveforms from various locations, some of which are not well recognized as being a site of tremor activity. The regions of interest are subduction zones at Nankai and Kyushu, Japan, Cascadia in western North America, Mexico, southern Chile, and New Zealand. Tremor locations are consistent with the geometry of subducting plates, and tremor depth tends to be shallower where younger plate is subducting. Tremor duration shows a negative correlation with tidal sensitivity, as reported previously in western Shikoku in the Nankai subduction zone. The duration is also related to the width of the tremor zone in the dip direction of the subducting plate. Linear structures, resembling striations, are observed in hypocenter distributions in western Shikoku and in the probability of short‐term migration direction. These spatial heterogeneities in tremor activity may be controlled by the heterogeneous frictional properties of the downgoing slab due to long‐term plate subduction, thereby providing information on the maturity of the plate interface.
A projection of permafrost degradation on the Tibetan Plateau during the 21st century
Authors: Guo Donglin , Wang Huijun , Li Duo
Published: January 2012

The current distribution and future change of permafrost on the Tibetan Plateau were examined using the Community Land Model version 4 (CLM4) with explicit treatment of frozen soil processes. When forced off‐line with archived high‐resolution data from The Abdus Salam International Centre for Theoretical Physics Regional Climate Model version 3 nested within the Model for Interdisciplinary Research on Climate 3.2 HiRes, the CLM4 produced a near‐surface permafrost area of 122.2 × 104 km2 for the Tibetan Plateau. This area compares reasonably with area estimates of 126.7 × 104 km2 for the Plateau frozen soil map. In response to the simulated strong Plateau warming (approximately 0.58°C per decade over the Tibetan Plateau for the period from 1980 to 2100 under the A1B greenhouse gas emissions scenario), the near‐surface permafrost area is projected to decrease by approximately 39% by the mid‐21st century and by approximately 81% by the end of the 21st century. The near‐surface permafrost area exhibits a significant decreasing linear trend, with a rate of decrease of 9.9 × 104 km2 per decade. The simulated deep permafrost area remains longer than the near‐surface permafrost for the same period. The active layer thickness of 0.5–1.5 m found in the present‐day increases to approximately 1.5–2.0 m by the period of 2030–2050. This increase will continue and reach a level of 2.0–3.5 m by the period of 2080–2100. Surface runoff decreases but subsurface runoff increases, both relative to the difference between precipitation and evapotranspiration. This is related to the fact that the decrease in ground ice content, as caused by permafrost degradation, facilitates the percolation of more water to deeper soil layers, thus resulting in the reallocation of runoff. These results provide useful references for evaluating the level of permafrost degradation in response to climate warming on the Tibetan Plateau.
Classification of Ascension Island and Natal ozonesondes using self‐organizing maps
Authors: Jensen Anders A. , Thompson Anne M. , Schmidlin F. J.
Published: January 2012

Ozone profiles from balloon‐borne ozonesondes are used for development of satellite algorithms and in chemistry‐climate model initialization, assimilation and evaluation. An important issue in the application of these profiles is how best to treat variations where varying photochemical and dynamical influences can cause the ozone mixing ratio in the tropospheric segments of the profile to change by of a factor of 2–3 within a day. Clustering techniques are an ideal way to approach the statistical classification of profile data and we apply self‐organizing maps to tropical tropospheric SHADOZ data, hypothesizing that the data will sort according to various influences on ozone, namely anthropogenic sources like biomass burning, meteorological conditions, and stratospheric or extra‐tropical intrusions. Self‐organizing maps, that use a learning algorithm to reveal the most prominent features of a data set according to a specified number of clusters, have been determined for the 1998–2009 SHADOZ profiles over Ascension Island (512 profiles, 7.98°S, 14.42°W) and Natal, Brazil (425 profiles, 5.42°S, 35.38°W). The 2 × 2 self‐organizing map, which creates 4 clusters, reveals that deviations from the average ozone in the free troposphere include both increased ozone resulting from seasonal biomass burning in Africa and locally reduced ozone brought about by convective lifting of unpolluted boundary‐layer air. Expanding to a 4 × 4 self‐organizing map shows how biomass burning influences the yearly cycle of tropospheric ozone at Ascension Island and captures the seasonality of ozone at both Ascension Island and Natal. Comparing Ascension Island and Natal using a 4 × 4 self‐organizing map at each site reveals similarities in mid‐tropospheric ozone, but shows differences in lower‐tropospheric ozone due to Ascension Island being closer to African biomass burning and more affected by descent from the mean Walker circulation, with less convective activity, than Natal.
Evidence for superthermal secondary electrons produced by SEP ionization in the Martian atmosphere
Authors: Lillis Robert J. , Brain David A. , Delory Gregory T. , Mitchell David L. , Luhmann Janet G. , Lin Robert P.
Published: January 2012

The atmosphere of Mars, lacking a global magnetic field, is exposed to the precipitation of solar energetic particles (SEPs), resulting in impact ionization and the production of secondary electrons, some of which may escape the atmosphere. In this study, we examine upward traveling fluxes of superthermal electrons between ∼100 and 650 eV, measured by the Mars Global Surveyor Magnetometer/Electron Reflectometer at 400 km altitude during nine of the largest and clearest SEP events of the last solar maximum from November 2000 until the “Halloween” storms of late 2003. We subtract the contribution from backscattered low‐energy precipitating electrons and find that, for the highest and most rarely observed SEP fluxes, we detect a statistically significant flux of SEP‐produced superthermal electrons escaping the Martian atmosphere. The measured fluxes are found to be in broad agreement with a calculation of expected upward electron fluxes resulting from ionization of neutrals by energetic proton impact. Peak SEP ionization rates on the nightside from the Halloween storms are found to be comparable to (although lower than) typical dayside photoionization rates and at least 3 orders of magnitude higher than average nightside electron impact ionization rates. Further advances in our knowledge of SEP effects on the Martian ionosphere await data from the Radiation Assessment Detector (RAD) instrument on the Mars Science Laboratory rover in 2012 and the MAVEN orbiter in 2014.
Comparison of stochastic methods for the variability assessment of technology parameters
Authors: Manfredi P. , Fontana M. , Stievano I. S. , Canavero F. G.
Published: January 2012

This paper provides and compares two alternative solutions for the simulation of cables and interconnects with the inclusion of the effects of parameter uncertainties, namely the Polynomial Chaos (PC) method and the Response Surface Modeling (RSM). The problem formulation applies to the telegraphers equations with stochastic coefficients. According to PC, the solution requires an expansion of the unknown parameters in terms of orthogonal polynomials of random variables. On the contrary, RSM is based on a least‐square polynomial fitting of the system response. The proposed methods offer accuracy and improved efficiency in computing the parameter variability effects on system responses with respect to the conventional Monte Carlo approach. These approaches are validated by means of the application to the stochastic analysis of a commercial multiconductor flat cable. This analysis allows us to highlight the respective advantages and disadvantages of the presented methods.
Modeling effects of floods on streambed hydraulic conductivity and groundwater‐surface water interactions
Authors: Simpson Scott C. , Meixner Thomas
Published: January 2012

Flood events can induce temporal changes in streambed elevation and particle‐size composition, which may influence the bed's hydraulic properties and stream‐aquifer fluxes during and after an event. This study combines a set of previously developed modeling approaches to create a synthetic flood event during which bed sediment is entrained and deposited as a function of hydraulic conditions and particle size. One simulated river reach in a state of approximate dynamic equilibrium is chosen to investigate the impacts of size‐selective sediment transport on stream‐aquifer interaction. Along this reach, the preferential entrainment of fine sediment during the flood's rising limb leads to overall bed coarsening, and increases in vertical hydraulic conductivity (Kbv) and downward fluxes of floodwater into the streambed. Progressively finer sediment layers are deposited during the event's falling limb, causing the redevelopment of a colmation (clogging) layer on the bed surface and a decline in overall Kbv by the event's conclusion. This reduction in Kbv leads to prolonged retention of event water in the streambed (after the reach reverts from losing to gaining river conditions) when compared with what is expected if pre‐event Kbv values are used to estimate river‐aquifer exchanges. This process of sequential bed coarsening and fining during a flood event provides a mechanistic explanation for the event size‐and‐duration threshold, inferred in some systems, that must be exceeded for significant amounts of flood recharge to occur. The major consequences of these processes—enhanced infiltration and prolonged floodwater retention—have potentially major implications for groundwater‐surface water interactions, water quality, contaminant transport, and riparian biogeochemistry.
Histone deacetylase 1 enhances microRNA processing via deacetylation of DGCR8
Authors: Wada Taeko , Kikuchi Jiro , Furukawa Yusuke
Published: January 2012

Relatively little is known about the regulatory mechanisms of the Drosha/DGCR8 complex, which processes miRNAs at the initial step of biogenesis. We found that histone deacetylase 1 (HDAC1) increases the expression levels of mature miRNAs despite repressing the transcription of host genes. HDAC1 is an integral component of the Drosha/DGCR8 complex and enhances miRNA processing by increasing the affinity of DGCR8 to primary miRNA transcripts via deacetylation of critical lysine residues in the RNA‐binding domains of DGCR8. This finding suggests that HDACs have two arms for gene silencing: transcriptional repression by promoter histone deacetylation and post‐transcriptional inhibition by increasing miRNA abundance.
Intra‐Abdominal Adipose Tissue Is Independently Associated With Sex‐Hormone Binding Globulin in Premenopausal Women
Authors: Azrad Maria , Gower Barbara A. , Hunter Gary R. , Nagy Tim R.
Published: January 2012

Lower serum concentrations of sex‐hormone binding globulin (SHBG) are associated with increased risk for several obesity‐related diseases in women including hormone‐sensitive cancers, type 2 diabetes, metabolic syndrome, and cardiovascular disease. Previous investigations have reported that body composition, specifically central obesity, and/or higher insulin concentrations are key factors associated with lower SHBG in overweight and obese women; however, these studies were limited by their cross‐sectional design. We hypothesized that intra‐abdominal adipose tissue (IAAT), a fat depot linked with an abnormal metabolic profile, is inversely and independently associated with SHBG. Therefore, we determined the longitudinal associations among SHBG, insulin, and IAAT in 107 premenopausal women enrolled in a weight loss study. Overweight (BMI 27–30 kg/m2) women were weight reduced until BMI of ≤24 was achieved. Body composition and IAAT were measured at baseline and after weight loss with dual‐energy X‐ray absorptiometry and computed tomography, respectively. Serum concentrations of insulin and SHBG were determined. Paired t‐test showed that insulin and IAAT decreased significantly and SHBG increased significantly following weight loss (P < 0.0001 for all). Simple correlations from baseline showed no association with insulin and SHBG (r = −0.142, P = 0.143) and a significant inverse association between IAAT and SHBG (r = −0.43, P < 0.0001). Repeated measures mixed‐model showed that after adjusting for age and time (weight loss), IAAT was significantly inversely associated with SHBG (P = 0.0002) and there was no association with insulin and SHBG (P = 0.180). We conclude that SHBG concentrations are influenced by IAAT and not insulin in premenopausal women.
Autoinhibition mechanism of the plasma membrane calcium pump isoforms 2 and 4 studied through lipid–protein interaction
Authors: Mangialavori Irene C. , Corradi Gerardo , Rinaldi Débora E. , de la Fuente María Candelaria , Adamo Hugo P. , Rossi Juan Pablo F. C.
Published: January 2012

The autoinhibition/activation of the PMCA (plasma membrane Ca2+-ATPase) involves conformational changes in the membrane region of the protein that affect the amount of lipids directly associated with the transmembrane domain. The lipid–protein-dependence of PMCA isoforms 2 and 4 expressed and obtained in purified form from Saccharomyces cerevisiae was investigated using the phosphatidylcholine analogue [125I]TID-PC/16 {l-O-hexadecanoyl-2-O-[9-[[[2-[125I]iodo-4-(trifluoromemyl-3H-diazirin-3-yl)benzyl]oxy]carbonyl]nonanoyl]-sn-glycero-3-phosphocholine}, which was incorporated into mixtures of dimyristoylphosphatidylcholine and the non-ionic detergent C12E10 [deca(ethylene glycol) dodecyl ether]. We found no differences between the recombinant PMCA4 and PMCA purified from erythrocytes (ePMCA). However, titration of the half-maximal activation by Ca2+/calmodulin of PMCA2 showed 30-fold higher affinity than PMCA4. PMCA2 exhibited a lower level of labelling in the autoinhibited conformation relative to PMCA4, indicating that the lower autoinhibition was correlated with a lower exposure to lipids in the autoinhibited state. Analysis of the lipid–protein stoichiometry showed that the lipid annulus of PMCA varies: (i) in accordance to the conformational state of the enzyme; and (ii) depending on the different isoforms of PMCA. PMCA2 during Ca2+ transport changes its conformation to a lesser extent than PMCA4, an isoform more sensitive to modulation by calmodulin and acidic phospholipids. This is the first demonstration of a dynamic behaviour of annular lipids and PMCA.
The Processing and Interpretation of Verb Phrase Ellipsis Constructions by Children at Normal and Slowed Speech Rates
Authors: Callahan Sarah M. , Walenski Matthew , Love Tracy
Published: January 2012

Purpose

To examine children's comprehension of verb phrase (VP) ellipsis constructions in light of their automatic, online structural processing abilities and conscious, metalinguistic reflective skill.

Method

Forty-two children ages 5 through 12 years listened to VP ellipsis constructions involving the strict/sloppy ambiguity (e.g., “The janitor untangled himself from the rope and the fireman in the elementary school did too after the accident.”) in which the ellipsis phrase (“did too”) had 2 interpretations: (a) strict (“untangled the janitor”) and (b) sloppy (“untangled the fireman”). We examined these sentences at a normal speech rate with an online cross-modal picture priming task (n= 14) and an offline sentence–picture matching task (n= 11). Both tasks were also given with slowed speech input (n= 17).

Results

Children showed priming for both the strict and sloppy interpretations at a normal speech rate but only for the strict interpretation with slowed input. Offline, children displayed an adultlike preference for the sloppy interpretation with normal-rate input but a divergent pattern with slowed speech.

Conclusions

Our results suggest that children and adults rely on a hybrid syntax-discourse model for the online comprehension and offline interpretation of VP ellipsis constructions. This model incorporates a temporally sensitive syntactic process of VP reconstruction (disrupted with slow input) and a temporally protracted discourse effect attributed to parallelism (preserved with slow input).

Supplemental Material

https://doi.org/10.23641/asha.14963562
Speech Perception With Music Maskers by Cochlear Implant Users and Normal-Hearing Listeners
Authors: Eskridge Elizabeth N. , Galvin John J. , Aronoff Justin M. , Li Tianhao , Fu Qian-Jie
Published: January 2012

Purpose

The goal of this study was to investigate how the spectral and temporal properties in background music may interfere with cochlear implant (CI) and normal-hearing listeners' (NH) speech understanding.

Method

Speech-recognition thresholds (SRTs) were adaptively measured in 11 CI and 9 NH subjects. CI subjects were tested while using their clinical processors; NH subjects were tested while listening to unprocessed audio. Speech was presented with different music maskers (excerpts from musical pieces) and with steady, speech-shaped noise. To estimate the contributions of energetic and informational masking, SRTs were also measured in “music-shaped noise” and in music-shaped noise modulated by the music temporal envelopes.

Results

NH performance was much better than CI performance. For both subject groups, SRTs were much lower with the music-related maskers than with speech-shaped noise. SRTs were strongly predicted by the amount of energetic masking in the music maskers. Unlike CI users, NH listeners obtained release from masking with envelope and fine structure cues in the modulated noise and music maskers.

Conclusions

Although speech understanding was greatly limited by energetic masking in both subject groups, CI performance worsened as more spectrotemporal complexity was added to the maskers, most likely due to poor spectral resolution.
Impact of unbalanced charge transport on the efficiency of normal and inverted solar cells
Authors: Kotlarski J. D. , Blom P. W. M.
Published: January 2012

In a normal solar cell, most charge carriers are generated close to the anode, such that electrons have to travel a longer distance as compared to the holes. In an inverted solar cell, holes have to travel a longer distance. We use a combined optical and electronic model to simulate the effect of unbalanced transport on the efficiency of normal and inverted single and tandem solar cells. When the electrons are ten times more mobile than the holes, the efficiency for a single cell with a thickness of 250 nm drops from 7.5% to 4.5% when changing from a normal to an inverted structure. For opposite mobility ratio, the inverted structure clearly outperforms the normal structure.
Static solutions from the point of view of comparison geometry
Authors: Reiris Martin
Published: January 2012

We analyze (the harmonic map representation of) static solutions of the Einstein equations in dimension three from the point of view of comparison geometry. We find simple monotonic quantities capturing sharply the influence of the Lapse function on the focussing of geodesics. This allows, in particular, a sharp estimation of the Laplacian of the distance function to a given (hyper)-surface. We apply the technique to asymptotically flat solutions with regular and connected horizons and, after a detailed analysis of the distance function to the horizon, we recover the Penrose inequality and the uniqueness of the Schwarzschild solution. The proof of this last result does not require proving conformal flatness at any intermediate step.
The gap equation for spin-polarized fermions
Authors: Freiji Abraham , Hainzl Christian , Seiringer Robert
Published: January 2012

We study the BCS gap equation for a Fermi gas with unequal population of spin-up and spin-down states. For cosh (δμ/T) ⩽ 2, with T the temperature and δμ the chemical potential difference, the question of existence of non-trivial solutions can be reduced to spectral properties of a linear operator, similar to the unpolarized case studied previously in [Frank, R. L., Hainzl, C., Naboko, S., and Seiringer, R., J., Geom. Anal. 17, 559–567 (2007)10.1007/BF02937429; Hainzl, C., Hamza, E., Seiringer, R., and Solovej, J. P., Commun., Math. Phys. 281, 349–367 (2008)10.1007/s00220-008-0489-2; and Hainzl, C. and Seiringer, R., Phys. Rev. B 77, 184517–110 435 (2008)]10.1103/PhysRevB.77.184517. For cosh (δμ/T) > 2 the phase diagram is more complicated, however. We derive upper and lower bounds for the critical temperature, and study their behavior in the small coupling limit.
Monte Carlo study of four dimensional binary hard hypersphere mixtures
Authors: Bishop Marvin , Whitlock Paula A.
Published: January 2012

A multithreaded Monte Carlo code was used to study the properties of binary mixtures of hard hyperspheres in four dimensions. The ratios of the diameters of the hyperspheres examined were 0.4, 0.5, 0.6, and 0.8. Many total densities of the binary mixtures were investigated. The pair correlation functions and the equations of state were determined and compared with other simulation results and theoretical predictions. At lower diameter ratios the pair correlation functions of the mixture agree with the pair correlation function of a one component fluid at an appropriately scaled density. The theoretical results for the equation of state compare well to the Monte Carlo calculations for all but the highest densities studied.
An immersed boundary method for Brownian dynamics simulation of polymers in complex geometries: Application to DNA flowing through a nanoslit with embedded nanopits
Authors: Zhang Yu , de Pablo Juan J. , Graham Michael D.
Published: January 2012

This work presents an immersed boundary method that allows fast Brownian dynamics simulation of solutions of polymer chains and other Brownian objects in complex geometries with fluctuating hydrodynamics. The approach is based on the general geometry Ewald-like method, which solves the Stokes equation with distributed regularized point forces in O(N) or \documentclass[12pt]{minimal}\begin{document}$O(N\text{log}N)$\end{document}O(NlogN) operations, where N is the number of point forces in the system. Time-integration is performed using a midpoint algorithm and Chebyshev polynomial approximation proposed by Fixman. This approach is applied to the dynamics of a genomic DNA molecule driven by flow through a nanofluidic slit with an array of nanopits on one wall of the slit. The dynamics of the DNA molecule was studied as a function of the Péclet number and chain length (the base case being λ-DNA). The transport characteristics of the hopping dynamics in this device differ at low and high Péclet number, and for long DNA, relative to the pit size, the dynamics is governed by the segments residing in the pit. By comparing with results that neglect them, hydrodynamic interactions are shown to play an important quantitative role in the hopping dynamics.
Long-range correlation energies from frequency-dependent weighted exchange-hole dipole polarisabilities
Authors: Heßelmann Andreas
Published: January 2012

Long-range correlation energies are calculated using an approximation of the single-particle density-density response function of the system that leads to an expression requiring only occupied orbitals and eigenvalues. Dipole-dipole polarisabilities and isotropic leading-order dispersion coefficients obtained from this approximation are shown to be in a reasonable agreement with corresponding values from the experiment or dipole oscillator strength distributions. The localised polarisabilities were used to calculate a long-range correlation correction to a hybrid-generalised gradient approximation functional using a proper damping function at short ranges. It was found that the hybrid density-functional theory+dispersion method obtained in this way has a comparable accuracy than high-level ab initio wave function methods at a much lower computational cost. This has been analysed for a number of systems from the GMTKN30 database including subsets for noncovalently bound complexes, relative energies for sugar conformers and reaction energies and barrier heights of pericyclic reactions of some medium sized organic molecules.
Structure, energetics, and reactions of alkali tetramers
Authors: Byrd Jason N. , Harvey Michels H. , Montgomery John A. , Côté Robin , Stwalley William C.
Published: January 2012

Electronic structure calculations have been carried out for all possible alkali tetramers that can be formed from X2 + X2 → X2X2, X2 + Y2 → X2Y2, and XY + XY → X2Y2 alkali dimer association reactions. Vibrationally stable rhombic (D2h) and planar (Cs) structures are found for all possible tetramers formed from the alkali metals, Li to Cs. All tetramer formation reactions (from ground state singlet homonuclear or heteronuclear dimers) are found to be exothermic with binding energies ranging from 6282 cm−1 for Li2Li2 to 1985 cm−1 for Cs2Cs2. Extensive calculations, carried out at long-range for several reactant pairs, indicate that there are barrier-less pathways for the formation of tetramers from dimer association reactions. At low temperatures, direct formation of tetramers is unlikely, owing to the large exothermicity associated with these association reactions, but atom exchange reactions (X2 + Y2 ↔ XY + XY) are possible for some species.
Photo-assisted bistable switching using Mott transition in two-terminal VO2 device
Authors: Seo Giwan , Kim Bong-Jun , Wook Lee Yong , Kim Hyun-Tak
Published: January 2012

In order to investigate bistable switching characteristics of planar junction devices based on vanadium dioxide (VO2) thin films, we have measured the optical power dependence of the threshold voltage of the device, at which a current jump, regarded as the Mott metal-insulator transition (MIT), happened, by using an infrared laser with a wavelength of ∼1.55 μm, illuminated onto the VO2 film. In a test closed loop circuit connecting a DC voltage source, a standard resistor, and a VO2 thin film device in series, the bistability of the voltage across the device (VD) was examined with respect to a variety of illumination powers (PLs). By triggering the forward or reverse phase transition (Mott MIT) of the VO2 film with “SET” or “RESET” optical pulse, respectively, the photo-assisted bistable switching of VD in the test circuit properly DC biased could be realized at an intermediate PL chosen between optical powers of “SET” and “RESET” pulses. In particular, the transient response of VD showed not only bistable states of VD but also their switching speed.
Atomic scale investigation of the abnormal transport properties in bilayer graphene nanoribbon
Authors: Li Yong-Jun , Li Ming-Da , Liu Jian-Shuang , Sun Qing-Qing , Zhou Peng , Wang Peng-Fei , Ding Shi-Jin , Wei Zhang David
Published: January 2012

We investigate the transport properties of bilayer AA-stacking zigzag graphene nanoribbons (bi-zGNRs) and observe abnormal I-V characteristics which are sensitive to the number of carbon chains across the ribbons. Combining the chirality selective rule of Dirac electrons in graphene and the symmetry of eigenstates, we attribute the abnormal current behavior to the chirality mismatch of energy states. The mismatch causes the suppression of transmission pathways between two electrodes which lead to saturated current with increasing bias for certain ribbons.
Luminescent properties of LiBaPO4:RE (RE = Eu2+, Tb3+, Sm3+) phosphors for white light-emitting diodes
Authors: Sun Jiayue , Zhang Xiangyan , Xia Zhiguo , Du Haiyan
Published: January 2012

Multicolor emitting phosphors LiBaPO4:RE (RE = Eu2+, Tb3+, Sm3+) reported as interesting down-conversion luminescent materials in white light-emitting diodes (w-LEDs) have been prepared by a conventional solid-state reaction. The excitation and emission spectra indicate that these phosphors can be effectively excited by the near-UV light, and emit blue, green, and red light, respectively. The photoluminescence properties, decay times, and Commission Internationale de I’Eclairage (CIE) chromaticity indexes are determined for various concentrations of the activators Eu2+, Tb3+, and Sm3+ in LiBaPO4 host. Furthermore, the temperature-dependent luminescence of these phosphors was investigated. The emission intensities of Tb3+- and Sm3+-doped LiBaPO4 increased unexpectedly with increasing temperature. This interesting phenomenon is proposed to be the result of two ground states in the configurational coordination diagram. The present investigation suggests that LiBaPO4:RE (RE = Eu2+, Tb3+, Sm3+) were potential candidates for application in w-LEDs.
Point defect states of exchange spin waves in all-ferromagnetic two-dimensional magnonic crystals
Authors: Yang Hui , Yun Guohong , Cao Yongjun
Published: January 2012

Using the plane-wave expansion method under supercell approximation, band structures of exchange spin waves propagating in all-ferromagnetic two-dimensional magnonic crystals with point defects are calculated. The results indicate that the point defects in these structures can create localized states inside the bandgap. The characteristics and the magnetization distributions of these localized states are studied. The results show that the group velocities of the localized states almostequal zero in the whole first Brillouin zone, and numbers of localized states and their frequency-positions in the bandgap are related to the size of the point defect. Magnonic crystalswith such defect states can be used as fabricating materials of narrow bandpass spin-wave filters.
Effect of glycerol and dimethyl sulfoxide on the phase behavior of lysozyme: Theory and experiments
Authors: Gögelein Christoph , Wagner Dana , Cardinaux Frédéric , Nägele Gerhard , Egelhaaf Stefan U.
Published: January 2012

Salt, glycerol, and dimethyl sulfoxide (DMSO) are used to modify the properties of protein solutions. We experimentally determined the effect of these additives on the phase behavior of lysozyme solutions. Upon the addition of glycerol and DMSO, the fluid–solid transition and the gas–liquid coexistence curve (binodal) shift to lower temperatures and the gap between them increases. The experimentally observed trends are consistent with our theoretical predictions based on the thermodynamic perturbation theory and the Derjaguin-Landau-Verwey-Overbeek model for the lysozyme-lysozyme pair interactions. The values of the parameters describing the interactions, namely the refractive indices, dielectric constants, Hamaker constant and cut-off length, are extracted from literature or are experimentally determined by independent experiments, including static light scattering, to determine the second virial coefficient. We observe that both, glycerol and DMSO, render the potential more repulsive, while sodium chloride reduces the repulsion.
Negative Magnus lift on a rotating sphere at around the critical Reynolds number
Authors: Muto Masaya , Tsubokura Makoto , Oshima Nobuyuki
Published: January 2012

Negative Magnus lift acting on a sphere rotating about the axis perpendicular to an incoming flow was investigated using large-eddy simulation at three Reynolds numbers of 1.0 × 104, 2.0 × 105, and 1.14 × 106. The numerical methods used were first validated on a non-rotating sphere, and the spatial resolution around the sphere was determined so as to reproduce the laminar separation, reattachment, and turbulent transition of the boundary layer observed in the vicinity of the critical Reynolds number. The rotating sphere exhibited a positive or negative Magnus effect depending on the Reynolds number and the imposed rotating speed. At Reynolds numbers in the subcritical or supercritical regimes, the direction of the Magnus lift force was independent of the rotational speed. In contrast, the lift force was negative in the critical regime when particular rotating speeds were imposed. This negative Magnus effect was investigated in the context of suppression or promotion of boundary layer transition around the separation point.
Three-dimensional swirling flows in a tall cylinder driven by a rotating endwall
Authors: Lopez J. M.
Published: January 2012

The onset and nonlinear dynamics of swirling flows in relatively tall cylinders driven by the rotation of an endwall are studied numerically. These flows are distinguished from the more widely studied swirling flows in shorter cylinders; the instability in the taller cylinders is direct to three-dimensional flows rather than to unsteady axisymmetric flows. The simulations are in very good agreement with recent experiments in terms of the critical Reynolds number, frequency, and azimuthal wavenumber of the flows, but there is disagreement in the interpretation of these flows. We show that these flows are indeed rotating waves and that they have the same vorticity distributions as the flows measured using particle image velocimetry in the experiments. Identifying these as rotating waves gives a direct connection with prior linear stability analysis and the three-dimensional flows found in shorter cylinders as secondary instabilities leading to modulated rotating waves.
Core-to-Rydberg band shift and broadening of hydrogen bonded ammonia clusters studied with nitrogen K-edge excitation spectroscopy
Authors: Yamanaka Takeshi , Tabayashi Kiyohiko , Takahashi Osamu , Tanaka Kenichiro , Namatame Hirofumi , Taniguchi Masaki
Published: January 2012

Nitrogen 1s (N ls) core-to-Rydberg excitation spectra of hydrogen-bonded clusters of ammonia (AM) have been studied in the small cluster regime of beam conditions with time-of-flight (TOF) fragment-mass spectroscopy. By monitoring partial-ion-yield spectra of cluster-origin products, “cluster” specific excitation spectra could be recorded. Comparison of the “cluster” band with “monomer” band revealed that the first resonance bands of clusters corresponding to N 1s → 3sa1/3pe of AM monomer are considerably broadened. The changes of the experimental core-to-Rydberg transitions ΔFWHM (N 1s → 3sa1/3pe) = ∼0.20/∼0.50 eV compare well with the x ray absorption spectra of the clusters generated by using density functional theory (DFT) calculation. The broadening of the core-to-Rydberg bands in small clusters is interpreted as being primarily due to the splitting of non-equivalent core-hole N 1s states caused by both electrostatic core-hole and hydrogen-bonding (H3N···H–NH2) interactions upon dimerization. Under Cs dimer configuration, core-electron binding energy of H−N (H-donor) is significantly decreased by the intermolecular core-hole interaction and causes notable redshifts of core-excitation energies, whereas that of lone-pair nitrogen (H-acceptor) is slightly increased and results in appreciable blueshifts in the core-excitation bands. The result of the hydrogen-bonding interaction strongly appears in the n−σ* orbital correlation, destabilizing H−N donor Rydberg states in the direction opposite to the core-hole interaction, when excited N atom with H−N donor configuration strongly possesses the Rydberg component of anti-bonding σ* (N−H) character. Contributions of other cyclic H-bonded clusters (AM)n with n ≥ 3 to the spectral changes of the N 1s → 3sa1/3pe bands are also examined.
Comparative study of magnetization reversal process between rectangular and circular thin film rings
Authors: Shimon G. , Adeyeye A. O. , Ross C. A.
Published: January 2012

The magnetization reversal processes of rectangular and circular permalloy ring arrays are compared. Rectangular rings reverse via two different processes, one of which includes the formation of a vortex state. The corners of the rectangular rings affect domain wall pinning and reverse domain nucleation processes and alter the field values for the two major transitions between magnetic states as compared to a circular ring. The effects of film thickness are also investigated. Micromagnetic simulations are compared with the experiment results.