bluuebunny/crossref_metadata_2025 huggingface dataset:
Cognitive Enrichment in Old Age
Authors: Schmiedek Florian , Bauer Colin , Lövdén Martin , Brose Annette , Lindenberger Ulman
Published: July 2010

Lifestyles with high levels of cognitive activity have been linked to weaker declines in cognitive abilities with aging. Hence, computer-based cognitive training programs that facilitate intense, daily, cognitive practice may help older adults to maintain and improve their cognitive functioning. We present the rationale for and implementation of an internet-based training environment that includes tasks of perceptual speed, episodic memory, and working memory. It was implemented as platform-independent internet-based testing software and used in the COGITO study to investigate intraindividual variability and plasticity in 101 younger (age 20–31) and 103 older (age 65–80) adults across an average of 100 daily practice sessions. Observations from this study and retrospective self-report evaluations demonstrate the program’s feasibility and acceptance among participants.
Ambient Assisted Living Research in the CareLab
Authors: de Ruyter Boris , Zwartkruis-Pelgrim Elly , Aarts Emile
Published: July 2010

As technology development progresses, the vision of ambient intelligence has provided a human-centric approach to applications of technology. In the context of aging societies, ambient intelligence has focused on providing assistive solutions for elders at risk of losing their independence. In this article we report on a research environment called CareLab and describe three projects that have studied the role of technology in the monitoring and coaching of older adults. By focusing on the need for a feeling of safety, cognitive stimulation, and social connectedness, these projects have investigated the role of technology applications for supporting the elderly in maintaining an independent lifestyle. Finally, we discuss some challenges crucial for the success of ambient assisted-living research.
Does Personality Modulate Skin Conductance Responses to Emotional Stimuli?
Authors: Mardaga Solange , Hansenne Michel
Published: July 2010

Several studies showed that personality modulates emotional responsiveness, though most of them used subjective ratings as the measure of emotion. The present study extends personality-emotion relationship findings to psychophysiological methods, more precisely to skin conductance responses (SCRs). SCRs were recorded in 54 normal subjects following the presentation of neutral and emotional pictures. Results showed that half-recovery time was modulated by harm avoidance (HA) as a function of emotional valence: Low-HA subjects showed longer half-recovery time following the presentation of pleasant pictures relative to neutral ones, whereas high-HA subjects showed no extended half-recovery time. These results support the hypothesis that personality modulates some aspects of somatic emotional reactivity, and together with previous results, they suggest that this phenomenon is highly dependent upon the characteristics of the emotional material.
Ratio or Length?
Authors: Schuurmans-Stekhoven James B. , Buckingham Robert Michael
Published: July 2010

Mounting evidence suggests a link between digit ratio (2D:4D) and personality – albeit with generally small effect sizes. While the identified effects are usually attributed to in utero biochemistry, the bivariate approach favored by researchers in this area does not rule out competing explanations. After first scrutinizing the independence of 2D:4D and overall finger length, we used a multivariate approach to predict the three-dimensional EPQ-R. Given that ring finger length and digit ratio varied conjointly, we introduced a logarithm of residuals model. This new method simultaneously addresses (1) the sensitivity of 2D:4D to measurement error and (2) the high correlations between 2D:4D and finger length. The traditional 2D:4D measure predicted neuroticism but not psychoticism. The logarithm of residuals model was able to identify specific personality effects for ring and index finger residuals. Both neuroticism and psychoticism were related to finger residual measures in a manner consistent with Manning’s in utero biochemistry theory.
Dipole tilt effects on the magnetosphere‐ionosphere convection system during interplanetary magnetic field BY‐dominated periods: MHD modeling
Authors: Watanabe Masakazu , Kabin Konstantin , Sofko George J. , Rankin Robert , Gombosi Tamas I. , Ridley Aaron J.
Published: July 2010

Using numerical magnetohydrodynamic simulations, we examine the dipole tilt effects on the magnetosphere‐ionosphere convection system when the interplanetary magnetic field is oblique northward (BY = 4 nT and BZ = 2 nT). In particular, we clarify the relationship between viscous‐driven convection and reconnection‐driven convection. The azimuthal locations of the two viscous cell centers in the equatorial plane rotate eastward (westward) when the dipole tilt increases as the Northern Hemisphere turns toward (away from) the Sun. This rotation is associated with nearly the same amount of eastward (westward) rotation of the equatorial crossing point of the dayside separator. The reason for this association is that the viscous cell is spatially confined within the Dungey‐type merging cell whose position is controlled by the separator location. The ionospheric convection is basically a round/crescent cell pattern, but the round cell in the winter hemisphere is significantly deformed. Between its central lobe cell portion and its outer Dungey‐type merging cell portion, the round cell streamlines are deformed owing to the combined effects of the viscous cell and the hybrid merging cell, the latter of which is driven by both Dungey‐type reconnection and lobe‐closed reconnection.
Combined CloudSat‐CALIPSO‐MODIS retrievals of the properties of ice clouds
Authors: Delanoë Julien , Hogan Robin J.
Published: July 2010

In this paper, data from spaceborne radar, lidar and infrared radiometers on the “A‐Train” of satellites are combined in a variational algorithm to retrieve ice cloud properties. The method allows a seamless retrieval between regions where both radar and lidar are sensitive to the regions where one detects the cloud. We first implement a cloud phase identification method, including identification of supercooled water layers using the lidar signal and temperature to discriminate ice from liquid. We also include rigorous calculation of errors assigned in the variational scheme. We estimate the impact of the microphysical assumptions on the algorithm when radiances are not assimilated by evaluating the impact of the change in the area‐diameter and the density‐diameter relationships in the retrieval of cloud properties. We show that changes to these assumptions affect the radar‐only and lidar‐only retrieval more than the radar‐lidar retrieval, although the lidar‐only extinction retrieval is only weakly affected. We also show that making use of the molecular lidar signal beyond the cloud as a constraint on optical depth, when ice clouds are sufficiently thin to allow the lidar signal to penetrate them entirely, improves the retrieved extinction. When infrared radiances are available, they provide an extra constraint and allow the extinction‐to‐backscatter ratio to vary linearly with height instead of being constant, which improves the vertical distribution of retrieved cloud properties.
Hydroclimatological impact of century‐long drainage in midwestern United States: CCSM sensitivity experiments
Authors: Kumar Sanjiv , Merwade Venkatesh , Lee Wonjun , Zhao Lan , Song Carol
Published: July 2010

Community Climate System Model (CCSM3) sensitivity experiments are performed to investigate the impact of past wetland drainage on the hydroclimatology of midwestern United States (MW USA). Coupled land surface and atmospheric components of CCSM3 are used at T85 (∼140 km) horizontal grid mesh size to create four control model experiments. These include: (1) 355 ppm CO2 for year 1990 excluding wetland (present condition), (2) 355 ppm CO2 for 1990 including wetland, (3) 289 ppm CO2 for year 1870 excluding wetland, and (4) 289 ppm CO2 for year 1870 including wetland. The CCSM3 control run for the present condition is validated with high‐resolution North American Regional Reanalysis (NARR) data for the Midwest region. Validation results show that CCSM3 is reasonable in simulating at‐surface incoming solar radiation, net short‐wave radiation, and 2 m air temperature. However, partitioning of net radiation into sensible and latent heat fluxes is imprecise, and summer precipitation is largely underestimated in CCSM3. To remove any biases in CCSM3 output, results from sensitivity experiments are analyzed in terms of difference in monthly climatology. Sensitivity experiment results show significant changes in summer sensible and latent heat fluxes due to wetland drainage. Near‐surface (2 m) air temperature has significantly increased, and convective precipitation has decreased by a small amount (∼50 mm) during the summer. Except for 2 m air temperature which is affected by both greenhouse gas emission–based climate change and wetland drainage over the last century, all other climatic variables are primarily affected by wetland drainage in the region.
Comparison of GOES‐retrieved and in situ measurements of deep convective anvil cloud microphysical properties during the Tropical Composition, Cloud and Climate Coupling Experiment (TC4)
Authors: Yost Christopher R. , Minnis Patrick , Ayers J. Kirk , Spangenberg Douglas A. , Heymsfield Andrew J. , Bansemer Aaron , McGill Matthew J. , Hlavka Dennis L.
Published: July 2010

One of the main goals of the Tropical Composition, Cloud and Climate Coupling Experiment (TC4) during July and August 2007 was to gain a better understanding of the formation and life cycle of cirrus clouds in the upper troposphere and lower stratosphere and how their presence affects the exchange of water vapor between these layers. Additionally, it is important to compare in situ measurements taken by aircraft instruments with products derived from satellite observations and find a meaningful way to interpret the results. In this study, cloud properties derived using radiance measurements from the Geostationary Operational Environmental Satellite (GOES) imagers are compared to similar quantities from aircraft in situ observations and are examined for meaningful relationships. A new method using dual‐angle satellite measurements is used to derive the ice water content (IWC) for the top portion of deep convective clouds and anvils. The results show the in situ and remotely sensed mean microphysical properties agree to within ∼10 μm in the top few kilometers of thick anvils despite the vastly different temporal and spatial resolutions of the aircraft and satellite instruments. Mean particle size and IWC are shown to increase with decreasing altitude in the top few kilometers of the cloud. Given these relationships, it may be possible to derive parameterizations for effective particle size and IWC as a function of altitude from satellite observations.
Characteristics of high‐precipitation events in Dronning Maud Land, Antarctica
Authors: Schlosser E. , Manning K. W. , Powers J. G. , Duda M. G. , Birnbaum G. , Fujita K.
Published: July 2010

High‐resolution Antarctic Mesoscale Prediction System archive data were used to investigate high‐precipitation events at the deep ice core drilling site Kohnen Station, Dronning Maud Land, Antarctica, during the period 2001–2006. The precipitation is found to be highly episodic, with, on average, approximately eight high‐precipitation events per year that can bring more than half of the total annual accumulation. The duration of the events varies between 1 day and about 1 week. On most days in the remaining time of the year, however, daily precipitation sums are about one order of magnitude smaller than that for the high‐precipitation events. Synoptic weather patterns causing these events were directly connected to frontal systems of cyclones in only 20% of the 51 investigated cases. The majority of the events occurred in connection with (blocking) anticyclones and correspondingly amplified Rossby waves, which lead to advection of warm, moist air from relatively low latitudes. Possible changes in the seasonality and frequency of these events in a different climate can lead to a bias in ice core properties and might also strongly influence the mass balance of the Antarctic continent and thus global sea level change.
Deriving confidence in paleointensity estimates
Authors: Paterson Greig A. , Heslop David , Muxworthy Adrian R.
Published: July 2010

Determining the strength of the ancient geomagnetic field (paleointensity) can be time consuming and can result in high data rejection rates. The current paleointensity database is therefore dominated by studies that contain only a small number of paleomagnetic samples (n). It is desirable to estimate how many samples are required to obtain a reliable estimate of the true paleointensity and the uncertainty associated with that estimate. Assuming that real paleointensity data are normally distributed, an assumption adopted by most workers when they employ the arithmetic mean and standard deviation to characterize their data, we can use distribution theory to address this question. Our calculations indicate that if we wish to have 95% confidence that an estimated mean falls within a ±10% interval about the true mean, as many as 24 paleomagnetic samples are required. This is an unfeasibly high number for typical paleointensity studies. Given that most paleointensity studies have small n, this requires that we have adequately defined confidence intervals around estimated means. We demonstrate that the estimated standard deviation is a poor method for defining confidence intervals for n < 7. Instead, the standard error should be used to provide a 95% confidence interval, thus facilitating consistent comparison between data sets of different sizes. The estimated standard deviation, however, should retain its role as a data selection criterion because it is a measure of the fidelity of a paleomagnetic recorder. However, to ensure consistent confidence levels, within‐site consistency criteria must be depend on n. Defining such a criterion using the 95% confidence level results in the rejection of ∼56% of all currently available paleointensity data entries.
MF/HF auroral radio emissions emanating from the topside ionosphere
Authors: Sato Y. , Ono T. , Sato N. , Fujii R.
Published: July 2010

This is a brief report on the first observation of polarization features and the source region of MF/HF auroral radio emissions emanating from the topside ionosphere. These emissions are called “Terrestrial Hectometric Radiation (THR)” and regarded as a counterpart of auroral roar and MF burst which are observable from the ground. THR typically occurs in either or both of two frequency bands near 1.5–2.0 MHz and 3.0–4.0 MHz, whose polarization features correspond to the L‐O and R‐X mode. The R‐X mode, which has never been reported as auroral roar and MF burst, can be attributed to nonlinear coupling of two upper hybrid waves. The Akebono satellite observation shows THR emissions merge with upper hybrid waves in a frequency‐time diagram under the matching condition fUH ∼ 2fce. This observation suggests that plasma instability enhances the upper hybrid waves under this condition, and then they are converted into MF/HF auroral radio emissions.
Erratum: Relative roles of niche and neutral processes in structuring a soil microbial community
Authors: Dumbrell Alex J , Nelson Michaela , Helgason Thorunn , Dytham Calvin , Fitter Alastair H
Published: July 2010

Correction to: The ISME Journal (2010) 4, 337–345; doi:10.1038/ismej.2009.122; published online 19 November 2009 Since the publication of this paper, the authors have noticed an error in Supplementary Figure 2. The corrected supplementary figure can be accessed via the online version of this corrigendum.
Tissue‐type plasminogen activator induces plasmin‐dependent proteolysis of intracellular neuronal nitric oxide synthase
Authors: Baron Amandine , Hommet Yannick , Cassé Frédéric , Vivien Denis
Published: July 2010

Background information. Despite its pro‐fibrinolytic activity, tPA (tissue plasminogen activator) is a serine protease known to influence a number of physiological and pathological functions in the central nervous system. Accordingly, tPA was reported to mediate some of its functions in the central nervous system through NMDA (N‐methyl‐d‐aspartate) receptors, LRP (low‐density lipoprotein receptor‐related protein) or annexin II.

Results. We provide here both in vitro and in vivo evidence that tPA could mediate proteolysis and subsequent delocalization of neuronal nitric oxide synthase, thereby reducing endogenous neuronal nitric oxide release. We also demonstrate that although this effect is independent of NMDA receptors, LRP signalling and calpain‐mediated proteolysis, it is dependent on the ability of tPA to promote the conversion of plasminogen into plasmin.

Conclusion. Altogether, these results demonstrate a new function for tPA in the central nervous system, which most likely contributes to its pleiotropic functions.
Fluorescent probe partitioning in giant unilamellar vesicles of ‘lipid raft’ mixtures
Authors: Juhasz Janos , Davis James H. , Sharom Frances J.
Published: July 2010

Direct visualization of raft-like lo (liquid-ordered) domains in model systems and cells using microscopic techniques requires fluorescence probes with known partitioning preference for one of the phases present. However, fluorescent probes may display dissimilar partitioning preferences in different lipid sys-tems and can also affect the phase behaviour of the host lipid bilayer. Therefore a detailed understanding of the behaviour of fluorescent probes in defined lipid bilayer systems with known phase behaviour is essential before they can be used for identifying domain phase states. Using giant unilamellar vesicles composed of the ternary lipid mixture DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine)/DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine)/cholesterol, for which the phase behaviour is known, we examined nine commonly used fluorescent probes using confocal fluorescence microscopy. The partitioning preference of each probe was assigned either on the basis of quantification of the domain area fractions or by using a well-characterized ld (liquid-disordered)-phase marker. Fluorescent probes were examined both individually and using dual or triple labelling approaches. Most of the probes partitioned individually into the ld phase, whereas only NAP (naphtho[2,3-a]pyrene) and NBD-DPPE [1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl] preferred the lo phase. We found that Rh-DPPE (Lissamine™ rhodamine B–1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine) increased the miscibility transition temperature, Tmix. Interestingly, the partitioning of DiIC18 (1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate) was influenced by Bodipy®-PC [2-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-1-hexa-decanoyl-sn-glycero-3-phosphocholine]. The specific use of each of the fluorescent probes is determined by its photostability, partitioning preference, ability to detect lipid phase separations and induced change in Tmix. We demonstrate the importance of testing a specific fluorescent probe in a given model membrane system, rather than assuming that it labels a particular lipid phase.
Spontaneous Regulation of Emotions in Preschool Children Who Stutter: Preliminary Findings
Authors: Johnson Kia N. , Walden Tedra A. , Conture Edward G. , Karrass Jan
Published: July 2010

Purpose

Emotional regulation of preschool children who stutter (CWS) and children who do not stutter (CWNS) was assessed through use of a disappointing gift (DG) procedure (P. M. Cole, 1986; C. Saarni, 1984, 1992).

Method

Participants consisted of 16 CWS and CWNS (11 boys and 5 girls in each talker group) who were 3 to 5 years of age. After assessing each child’s knowledge of display rules about socially appropriate expression of emotions, the authors asked the children to participate in a DG procedure. The children received a desirable gift preceding the first free-play task and a disappointing gift preceding a second free-play task. Dependent variables consisted of participants' positive and negative expressive nonverbal behaviors exhibited during receipt of a desirable gift and disappointing gift as well as conversational speech disfluencies exhibited following receipt of each gift.

Results

Findings indicated that CWS and CWNS exhibited no significant differences in amount of positive emotional expressions after receiving the desired gift; however, CWS—when compared with CWNS—exhibited more negative emotional expressions after receiving the undesirable gift. Furthermore, CWS were more disfluent after receiving the desired gift than after receiving the disappointing gift. Ancillary findings also indicated that CWS and CWNS had equivalent knowledge of display rules.

Conclusion

Findings suggest that efforts to concurrently regulate emotional behaviors and that speech disfluencies may be problematic for preschool-age CWS.
Auxiliary BE Production by African American English–Speaking Children With and Without Specific Language Impairment
Authors: Garrity April W. , Oetting Janna B.
Published: July 2010

Purpose

To examine 3 forms (
am,
is,
are
) of auxiliary BE production by African American English (AAE)–speaking children with and without specific language impairment (SLI).

Method

Thirty AAE speakers participated: 10 six-year-olds with SLI, 10 age-matched controls, and 10 language-matched controls. BE production was examined through samples and a probe.

Results

Across tasks, visual inspection suggested that the children with SLI overtly marked BE at lower rates than the controls, and all groups marked
am
at higher rates than
is
and
are,
with few dialect-inappropriate errors. Within the samples, the children also overtly marked
is
at higher rates when preceded by
it
/
that
/
what
than when it was preceded by a personal pronoun. A subset of these results was confirmed statistically. The children’s marking of BE also varied across tasks; for the age-matched controls, this variation was tied to their AAE dialect densities.

Conclusions

These findings show across-dialect similarities and differences between children’s acquisition of AAE and mainstream American English. Similarities involve the rate of the children’s BE marking as a function of their clinical status and the nature of their dialect-inappropriate errors. Differences involve the children’s rates of BE marking as a function of the form, context, and task.
Relation of Vocal Tract Shape, Formant Transitions, and Stop Consonant Identification
Authors: Story Brad H. , Bunton Kate
Published: July 2010

Purpose

The present study was designed to investigate the relation of formant transitions to place-of-articulation for stop consonants. A speech production model was used to generate simulated utterances containing voiced stop consonants, and a perceptual experiment was performed to test their identification by listeners.

Method

Based on a model of the vocal tract shape, a theoretical basis for reducing highly variable formant transitions to more invariant formant deflection patterns as a function of constriction location was proposed. A speech production model was used to simulate vowel–consonant–vowel (VCV) utterances for 3 underlying vowel–vowel contexts and for which the constriction location was incrementally moved from the lips toward the velar part of the vocal tract. These simulated VCVs were presented to listeners who were asked to identify the consonant.

Results

Listener responses indicated that phonetic boundaries were well aligned with points along the vocal tract length where there was a shift in the deflection polarity of either the 2nd or 3rd formant.

Conclusions

This study demonstrated that regions of the vocal tract exist that, when constricted, shift the formant frequencies in a predictable direction. Based on a perceptual experiment, the boundaries of these acoustically defined regions were shown to coincide with phonetic categories for stop consonants.

Supplemental Material

https://doi.org/10.23641/asha.6170348
Mood and Substance Use Disorders Among Adults Seeking Speech Treatment for Stuttering
Authors: Iverach Lisa , Jones Mark , O’Brian Sue , Block Susan , Lincoln Michelle , Harrison Elisabeth , Hewat Sally , Menzies Ross G. , Packman Ann , Onslow Mark
Published: July 2010

Objectives

Stuttering has been associated with a range of anxiety disorders, including social phobia. In the general community, anxiety disorders are frequently associated with increased rates of mood and substance use disorders. Therefore, in the present study, the authors sought to determine the rate of mood and substance use disorders among adults who stutter.

Method

The study employed a matched case–control design. Participants included 92 adults seeking treatment for stuttering and 920 age- and gender-matched controls. Mental health assessments were conducted via a computerized psychiatric diagnostic interview. Conditional logistic regression models were used to estimate odds ratios for the prevalence of mood and substance use disorders in both groups.

Results

When compared with matched controls, adults seeking treatment for stuttering had twofold increased odds of meeting criteria for a 12-month diagnosis of any mood disorder but were not found to report significantly higher lifetime prevalence rates for any substance use disorder.

Conclusions

Although adults who stutter in the present study were characterized by significantly higher rates of mood disorders than matched controls, they do not appear to self-medicate with substances such as alcohol. Results are discussed in terms of treatment implications and possible reasons why adults who stutter may avoid alcohol.
The Impact of Vocal Hyperfunction on Relative Fundamental Frequency During Voicing Offset and Onset
Authors: Stepp Cara E. , Hillman Robert E. , Heaton James T.
Published: July 2010

Purpose

This study tested the hypothesis that individuals with vocal hyperfunction would show decreases in relative fundamental frequency (RFF) surrounding a voiceless consonant.

Method

This retrospective study of 2 clinical databases used speech samples from 15 control participants and women with hyperfunction-related voice disorders: 82 prior to treatment (muscle tension dysphonia,
n
= 22; vocal fold nodules,
n
= 30; vocal fold polyps,
N
= 30) and 18 before and after surgical removal of vocal fold nodules or polyps. Acoustic samples were analyzed with respect to the RFF at the offset and onset of voicing surrounding a voiceless consonant.

Results

Individuals with vocal hyperfunction in a large clinical sample showed significant lowering of offset and onset RFF compared with controls. Voicing offset and onset RFFs were not significantly changed by the removal of vocal fold lesions in the surgical group.

Conclusions

Altered offset and onset RFF in patients with hyperfunction-related voice disorders can be interpreted as a by-product of heightened levels of laryngeal muscle tension. Measurement of RFF during voice offset and onset has potential for use as a simple, noninvasive measure of vocal hyperfunction.
Universality of Zener tunneling in homojunction p-n diodes
Authors: Majumdar Amlan , Lauer Isaac , O’Regan Terrance
Published: July 2010

We show that in homojunction p-n diodes made of semiconductors with unequal electron and hole effective masses, Zener tunneling is approximately universal, but not perfectly universal, as a function of effective tunneling width, where the effective tunneling width takes the effects of band curvature into account. We find that the curvature correction (CC), which is applied to obtain the approximate universality of tunneling, is by itself not universal but show that (1−CC)∕N2 is universal as a function of the tunneling width for a given material, where N is the doping density.
Construction of classical superintegrable systems with higher order integrals of motion from ladder operators
Authors: Marquette Ian
Published: July 2010

We construct integrals of motion for multidimensional classical systems from ladder operators of one-dimensional systems. This method can be used to obtain new systems with higher order integrals. We show how these integrals generate a polynomial Poisson algebra. We consider a one-dimensional system with third order ladder operators and found a family of superintegrable systems with higher order integrals of motion. We obtain also the polynomial algebra generated by these integrals. We calculate numerically the trajectories and show that all bounded trajectories are closed.
Assigning quantum labels to variationally computed rotational-vibrational eigenstates of polyatomic molecules
Authors: Mátyus Edit , Fábri Csaba , Szidarovszky Tamás , Czakó Gábor , Allen Wesley D. , Császár Attila G.
Published: July 2010

A procedure is investigated for assigning physically transparent, approximate vibrational and rotational quantum labels to variationally computed eigenstates. Pure vibrational wave functions are analyzed by means of normal-mode decomposition (NMD) tables constructed from overlap integrals with respect to separable harmonic oscillator basis functions. Complementary rotational labels JKaKc are determined from rigid-rotor decomposition (RRD) tables formed by projecting rotational-vibrational wave functions (J≠0) onto products of symmetrized rigid-rotor basis functions and previously computed (J=0) vibrational eigenstates. Variational results for H2O, HNCO, trans-HCOD, NCCO, and H2CCO are presented to demonstrate the NMD and RRD schemes. The NMD analysis highlights several resonances at low energies that cause strong mixing and cloud the assignment of fundamental vibrations, even in such simple molecules. As the vibrational energy increases, the NMD scheme documents and quantifies the breakdown of the normal-mode model. The RRD procedure proves effective in providing unambiguous rotational assignments for the chosen test molecules up to moderate J values.
A low-cost millimeter wave interferometer for remote vibration sensing
Authors: Smith Martin L. , Scales John A. , Weiss Manoja , Zadler Brian
Published: July 2010

Remote sensing of ground vibration is a key tool in the detection of shallowly buried objects, such as land mines. Millimeter wave systems show promise for replacing laser Doppler vibrometers as the key sensing technology on the grounds of reduced cost and because they provide a larger (10 cm versus 1 mm), more robust sensor footprint. We have developed a double-conversion interferometer operating at 39 GHz that can be built for about $10 000. The system employs quadrature detection in order to provide reliable sensitivity over wavelength-sized changes in target range. Laboratory tests show that it can estimate sinusoidal ground motion from a 1 s time series with an uncertainty of about 5 μm.
Dipolar sticky hard spheres within the Percus–Yevick approximation plus orientational linearization
Authors: Gazzillo Domenico
Published: July 2010

We consider a strongly idealized model for polar fluids, which consists of spherical particles, having, in addition to a hard-core repulsion, a “surface dipolar” interaction, acting only when particles are exactly at contact. A fully analytic solution of the molecular Orstein–Zernike equation is found for this potential, within the Percus–Yevick approximation complemented by a linearization of the angular dependence on molecular orientations (Percus–Yevick closure with orientational linearization). Numerical results are also presented in a detailed analysis about the local orientational structure. From the pair correlation function g(1,2), we first derive the best orientations of a test particle which explores the space around an arbitrary reference molecule. Then some local and global order parameters, related to the polarization induced by the reference particle, are also calculated. The local structure of this model with only short-ranged anisotropic interactions turns out to be, at least within the chosen approximation, qualitatively different from that of hard spheres with fully long-ranged dipolar potentials.
Structural modeling of carbonaceous mesophase amphotropic mixtures under uniaxial extensional flow
Authors: Golmohammadi Mojdeh , Rey Alejandro D.
Published: July 2010

The extended Maier–Saupe model for binary mixtures of model carbonaceous mesophases (uniaxial discotic nematogens) under externally imposed flow, formulated in previous studies [M. Golmohammadi and A. D. Rey, Liquid Crystals 36, 75 (2009); M. Golmohammadi and A. D. Rey, Entropy 10, 183 (2008)], is used to characterize the effect of uniaxial extensional flow and concentration on phase behavior and structure of these mesogenic blends. The generic thermorheological phase diagram of the single-phase binary mixture, given in terms of temperature (T) and Deborah (De) number, shows the existence of four T-De transition lines that define regions that correspond to the following quadrupolar tensor order parameter structures: (i) oblate (⊥,∥), (ii) prolate (⊥,∥), (iii) scalene O(⊥,∥), and (iv) scalene P(⊥,∥), where the symbols (⊥,∥) indicate alignment of the tensor order ellipsoid with respect to the extension axis. It is found that with increasing T the dominant component of the mixture exhibits weak deviations from the well-known pure species response to uniaxial extensional flow (uniaxial ⊥nematic→biaxial nematic→uniaxial∥paranematic). In contrast, the slaved component shows a strong deviation from the pure species response. This deviation is dictated by the asymmetric viscoelastic coupling effects emanating from the dominant component. Changes in conformation (oblate⇄prolate) and orientation (⊥⇄∥) are effected through changes in pairs of eigenvalues of the quadrupolar tensor order parameter. The complexity of the structural sensitivity to temperature and extensional flow is a reflection of the dual lyotropic/thermotropic nature (amphotropic nature) of the mixture and their cooperation/competition. The analysis demonstrates that the simple structures (biaxial nematic and uniaxial paranematic) observed in pure discotic mesogens under uniaxial extensional flow are significantly enriched by the interaction of the lyotropic/thermotropic competition with the binary molecular architectures and with the quadrupolar nature of the flow.
Emergence of equilibrium thermodynamic properties in quantum pure states. II. Analysis of a spin model system
Authors: Fresch Barbara , Moro Giorgio J.
Published: July 2010

A system composed of identical spins and described by a quantum mechanical pure state is analyzed within the statistical framework presented in Part I of this work. We explicitly derive the typical values of the entropy, of the energy, and of the equilibrium reduced density matrix of a subsystem for the two different statistics introduced in Part I. In order to analyze their consistency with thermodynamics, these quantities of interest are evaluated in the limit of large number of components of the isolated system. The main results can be summarized as follows: typical values of the entropy and of the equilibrium reduced density matrix as functions of the internal energy in the fixed expectation energy ensemble do not satisfy the requirement of thermodynamics. On the contrary, the thermodynamical description is recovered from the random pure state ensemble (RPSE), provided that one considers systems large enough. The thermodynamic limit of the considered properties for the spin system reveals a number of important features. First canonical statistics (and thus, canonical typicality as long as the fluctuations around the average value are small) emerges without the need of assuming the microcanonical space for the global pure state. Moreover, we rigorously prove (i) the equivalence of the “global temperature,” derived from the entropy equation of state, with the “local temperature” determining the canonical state of the subsystems; and (ii) the equivalence between the RPSE typical entropy and the canonical entropy for the overall system.
Outgassing and degradation of polyimide induced by swift heavy ion irradiation at cryogenic temperature
Authors: Severin D. , Balanzat E. , Ensinger W. , Trautmann C.
Published: July 2010

Polyimide foils were irradiated with energetic Kr (740 MeV) and Pb (890 MeV) ions at cryogenic temperature (12 K). Beam-induced degradation processes were monitored by residual gas analysis and online infrared spectroscopy. The outgassing components observed at low irradiation temperatures differ in quantity but are similar in mass distribution to those identified at room temperature exposure. Besides CO as major volatile fragment, a significant contribution of short hydrocarbons like C2Hx is released. In situ infrared spectroscopy indicates accumulation of CO and CO2 molecules at 12 K in the foils. During heat-up cycles, most of these frozen gases become mobile and outgas at a temperature between 35 and 55 K. The study is motivated by the application of polyimide foils as insulating material in high radiation environment of the future accelerator facility for antiproton and ion research (FAIR).
Calculation of field emission enhancement for TiO2 nanotube arrays
Authors: Alivov Yahya , Molloi Sabee
Published: July 2010

Numerical simulations of field emission of the titanium dioxide (TiO2) nanotube (NT) arrays on a planar cathode were performed by solving the Laplace equation. The studies showed that the field enhancement factor of TiO2 NT array first increased, and then reached the “saturated” maximum value when intertube distance s was close to NT height h. The emission current density also increased with spacing but started decreasing after s=2h. The behavior of field enhancement factor and emission current density was interpreted taking into account field screening effects. The anode–cathode distance has little effect on the field emission properties of TiO2 NT arrays.
Structural stability versus conformational sampling in biomolecular systems: Why is the charge transfer efficiency in G4-DNA better than in double-stranded DNA?
Authors: Woiczikowski P. Benjamin , Kubař Tomáš , Gutiérrez Rafael , Cuniberti Gianaurelio , Elstner Marcus
Published: July 2010

The electrical conduction properties of G4-DNA are investigated using a hybrid approach, which combines electronic structure calculations, molecular dynamics (MD) simulations, and the formulation of an effective tight-binding model Hamiltonian. Charge transport is studied by computing transmission functions along the MD trajectories. Though G4-DNA is structurally more stable than double-stranded DNA (dsDNA), our results strongly suggest that the potential improvement of the electrical transport properties in the former is not necessarily related to an increased stability, but rather to the fact that G4 is able to explore in its conformational space a larger number of charge-transfer active conformations. This in turn is a result of the non-negligible interstrand matrix elements, which allow for additional charge transport pathways. The higher structural stability of G4 can however play an important role once the molecules are contacted by electrodes. In this case, G4 may experience weaker structural distortions than dsDNA and thus preserve to a higher degree its conduction properties.
Linear spatial instability of viscous flow of a liquid sheet through gas
Authors: Altimira M. , Rivas A. , Ramos J. C. , Anton R.
Published: July 2010

The present paper focuses on the linear spatial instability of a viscous two-dimensional liquid sheet bounded by two identical viscous gas streams. The Orr–Sommerfeld differential equations and the boundary conditions of the flow configuration are numerically solved using Chebyshev series expansions and the collocation method. The strong dependence of the instability parameters on the velocity profiles is proven by using both quadratic and error functions to define the base flow in the liquid sheet and the gas shear layer. The sensitivity of the spatial instability growth rate to changes in the dimensionless parameters of the problem is assessed. Regarding the liquid sheet Reynolds number, it has been observed that, when this parameter increases, both the most unstable growth rate and the corresponding wavenumber decrease, whereas the cutoff wavenumber increases. The results of this analysis are compared with temporal theory through Gaster transformation. The effects liquid and gas viscosity have on instability are studied by comparing the instability curves given by the presented model with those from an inviscid liquid sheet and a viscous liquid sheet in an inviscid gaseous medium. The model presented in this paper features a variation in the cutoff wavenumber with all the governing parameters of the problem, whereas that provided by cases that account for an inviscid surrounding gas depends only on the liquid sheet Weber number and the ratio of gas to liquid densities. Results provided by the presented model have been experimentally validated and show that quadratic profiles have a greater capacity to predict the disturbance wavelength.
Micro-optofluidic Lenses: A review
Authors: Nguyen Nam-Trung
Published: July 2010

This review presents a systematic perspective on the development of micro-optofluidic lenses. The progress on the development of micro-optofluidic lenses are illustrated by example from recent literature. The advantage of micro-optofluidic lenses over solid lens systems is their tunability without the use of large actuators such as servo motors. Depending on the relative orientation of light path and the substrate surface, micro-optofluidic lenses can be categorized as in-plane or out-of-plane lenses. However, this review will focus on the tunability of the lenses and categorizes them according to the concept of tunability. Micro-optofluidic lenses can be either tuned by the liquid in use or by the shape of the lens. Micro-optofluidic lenses with tunable shape are categorized according to the actuation schemes. Typical parameters of micro-optofluidic lenses reported recently are compared and discussed. Finally, perspectives are given for future works in this field.
A uniformly redundant imaging array of penumbral apertures coupled with a heuristic reconstruction for hard x-ray and neutron imaging
Authors: Ueda Tatsuki , Fujioka Shinsuke , Nozaki Shinya , Azuma Rumiko , Chen Yen-Wei , Nishimura Hiroaki
Published: July 2010

A coded imaging and decoding (image reconstruction) scheme was developed for diagnosing a hot and dense region emitting hard x-rays and neutrons in laser-fusion plasmas. Because the imager was a uniformly redundant array of penumbral aperture (URPA) arranged in an M-matrix, URPA leads to N times (N: the total number of apertures) enhancement of signal intensity in comparison with a single penumbral aperture. A recorded penumbral image was reconstructed by a computer-based heuristic method to reduce artifacts caused by noises contained in a penumbral image. Applicability of this technique was investigated by imaging x-rays emitted from laser-produced plasmas, demonstrating a spatial resolution of 16 μm. Under the present conditions, the spatial resolution was determined dominantly by a detector resolution (10.5 μm) and a signal-to-noise ratio of the obtained penumbral image.
Photoluminescence studies on structural defects and room temperature ferromagnetism in Ni and Ni–H doped ZnO nanoparticles
Authors: Tong Liu-Niu , Cheng Teng , Han Huai-Bin , Hu Jin-Lian , He Xian-Mei , Tong Yan , Schneider Claus M.
Published: July 2010

We explore the effects of hydrogenated annealing on the crystal structure, room temperature ferromagnetism (RT-FM) and photoluminescence (PL) properties of Ni-doped ZnO (Zn1−xNixO, x=0.0 to 0.2) nanoparticles prepared by a sol-gel method. The x-ray photoelectron spectra and x-ray diffraction data provide evidence that Ni has been incorporated into the wurtzite ZnO lattice as Ni2+ ions substituting for Zn2+ ions at x≤0.05. A secondary phase of NiO type begins to form inside ZnO when x>0.05 and segregates from ZnO host lattice at x=0.2, leading to a large variation in the lattice constants of ZnO. The magnetization measurements show that the saturation magnetization (Ms) increases with increasing Ni concentration in the single-phase Zn1−xNixO (x≤0.05) nanoparticles. The secondary phase formation reduces the magnetization of Zn1−xNixO (x=0.1 and 0.15), while the segregation of NiO from the ZnO lattice at x=0.2 is accompanied by a large increase in Ms again. The PL measurements show that the UV emission intensity of single-phase Zn1−xNixO (x≤0.05) nanoparticles increases with a blueshift in the UV emission line when the Ni concentration increases, while the dominant green emission intensity decreases with increasing Ni dopant. The PL data strongly suggest that the FM in single-phase Zn1−xNixO (x≤0.05) nanoparticles is intrinsically correlated with a doping induced increase in the electron concentration in the conduction band of Ni-doped ZnO. After H2-annealing, the single-phase Zn1−xNixO:H (x≤0.05) nanoparticles show increases in both coercivity and saturation magnetization. The PL and diffuse reflectance spectra suggest that hydrogen-related shallow donors and an improved sample quality may be responsible for the H2-annealing induced enhancement of the RT-FM. The obvious correlation between FM and carrier concentration in Ni and Ni–H doped ZnO points towards a mechanism of carrier-mediated FM for Ni-doped ZnO diluted magnetic semiconductors.
Solid-state Marx based two-switch voltage modulator for the On-Line Isotope Mass Separator accelerator at the European Organization for Nuclear Research
Authors: Redondo L. M. , Silva J. Fernando , Canacsinh H. , Ferrão N. , Mendes C. , Soares R. , Schipper J. , Fowler A.
Published: July 2010

A new circuit topology is proposed to replace the actual pulse transformer and thyratron based resonant modulator that supplies the 60 kV target potential for the ion acceleration of the On-Line Isotope Mass Separator accelerator, the stability of which is critical for the mass resolution downstream separator, at the European Organization for Nuclear Research. The improved modulator uses two solid-state switches working together, each one based on the Marx generator concept, operating as series and parallel switches, reducing the stress on the series stacked semiconductors, and also as auxiliary pulse generator in order to fulfill the target requirements. Preliminary results of a 10 kV prototype, using 1200 V insulated gate bipolar transistors and capacitors in the solid-state Marx circuits, ten stages each, with an electrical equivalent circuit of the target, are presented, demonstrating both the improved voltage stability and pulse flexibility potential wanted for this new modulator.
Comparison of absorbed fractions of electrons and photons using three kinds of computational phantoms of rat
Authors: Xie Tianwu , Zhang Guozhi , Li Yun , Liu Qian
Published: July 2010

Rats have been widely used in radiopharmaceutics researches, making it reasonable to develop fine structured computational models for rat internal dose investigation. In this work, we developed three existing types of computational phantoms based on the same data set of rat, simulated photon and electron particles transport using Monte Carlo method and calculated absorbed fractions for organs. We further compared the dose discrepancies of these three types of phantoms in internal dosimetry and found the stylized phantom might cause an underestimation of the self-absorbed S-factors. The developed phantoms will contribute to the application of computational phantoms in dosimetry studies.
Pore-size dependence of the thermal conductivity of porous silicon: A phonon hydrodynamic approach
Authors: Alvarez F. X. , Jou D. , Sellitto A.
Published: July 2010

Phonon hydrodynamics is used to analyze the influence of porosity and of pore size on reduction in thermal conductivity in porous silicon, with respect to crystalline silicon. The expressions predict that the thermal conductivity is lower for higher porosity and for smaller pore radius, as a consequence of phonon ballistic effects. The theoretical results describe experimental data better than the assumption that they only depend on porosity.