bluuebunny/crossref_metadata_2025 huggingface dataset:
Sartre,Existentialism and Humanism
Authors: Baldwin Thomas
Published: February 2012

Sartre presented ‘Existentialism and Humanism’ to a popular audience in Paris late in 1945. As he implies in the discussion which is appended to the text of the lecture (pp. 57–58), he was here simplifying his views so as to make them intelligible to a wide audience. In this he succeeded only too well; the lecture has become exceedingly well known and has been regarded as a definitive presentation not only of Sartre's philosophy at the time, but also of ‘existentialism’. One thing I hope to show in this essay is that this is not a sensible view to take; Sartre's text requires a good deal of interpretation and qualification in the light of his other writings of the period, and what emerges is a position which is uniquely his own. One way in which this can be seen is by considering Heidegger's ‘Letter on Humanism’ of 1947 which is a response to Sartre's lecture and is, indeed, Heidegger's only direct response to Sartre's work. In the lecture Sartre had associated Heidegger with himself as an ‘existential atheist’ (p. 26), but in his letter Heidegger emphatically dissociates himself both from atheism and from existentialism as characterized by Sartre, and goes on to criticize the position advanced by Sartre in the lecture. Yet despite the popular exaggeration of the significance of Sartre's lecture, it is certainly worth studying; for not only is it short and accessible, though in some respects misleading, it is also one of Sartre's few indications of the positive ethical theory which so many of his writings require but do not supply.
Benefits of Order: The Influence of Item Sequencing on Metacognition in Moderate and Severe Traumatic Brain Injury
Authors: Chiou Kathy S. , Hillary Frank G.
Published: February 2012

The ability to appraise one's own ability has been found to have an important role in the recovery and quality of life of clinical populations. Examinee and task variables have been found to influence metacognition in healthy students; however the effect of these variables on the metacognitive accuracy of adults with neurological insult, such as traumatic brain injury (TBI), remains unknown. Twenty-two adults with moderate and severe TBI and a matched sample of healthy adults participated in this study examining the influence of item sequencing on metacognitive functioning. Retrospective confidence judgments were collected while participants completed a modified version of the Matrix Reasoning subtest. Significant influence of item sequence order was found, revealing better metacognitive abilities and performance when participants completed tasks where item difficulty progressed in order from easy to difficult. We interpret these findings to suggest that the sequencing of item difficulty offers “anchors” for gauging and adjusting to task demands. (JINS, 2012,18, 379–383)
The cost associated with disease-related malnutrition in Ireland
Authors: Rice Niamh , Normand Charles
Published: February 2012

Objective

The present study aimed to establish the annual public expenditure arising from the health and social care of patients with diet-related malnutrition (DRM) in the Republic of Ireland.

Design

Costs were calculated by (i) estimating the prevalence of DRM in health-care settings derived from age-standardised comparisons between available Irish data and large-scale UK surveys and (ii) applying relevant costs from official sources to estimates of health-care utilisation by adults with DRM. No attempt has been made to estimate separately the costs of DRM and any associated disease, since each can be a cause or consequence of the other. The methods used are adapted from an evaluation of the cost of malnutrition in the UK by the British Association for Parenteral and Enteral Nutrition (2009).

Settings

Hospitals, nursing homes, out-patient clinics, primary-care clinics and home care.

Subjects

All adult patients receiving hospital in-patient, out-patient or specified community health-care services.

Results

The annual public health and social care cost associated with adult malnourished patients in Ireland is estimated at over €1·4 billion, representing 10 % of the health-care budget. Most of this cost arises in acute hospital or residential care settings (i.e. 70 %), with nutritional support estimated to account for <3 % of spend.

Conclusions

The cost associated with the care of patients with DRM is substantial and may rise as the proportion of older people within the population increases, a group at increased risk of DRM. Despite growing pressure on health-care budgets, little attention has been focused on the economic burden associated with DRM in Ireland or the potential for savings arising from improved detection and treatment of those at risk.
Effect of high doses of folic acid supplementation in early pregnancy on child neurodevelopment at 18 months of age: the mother–child cohort ‘Rhea’ study in Crete, Greece
Authors: Chatzi Leda , Papadopoulou Eleni , Koutra Katerina , Roumeliotaki Theano , Georgiou Vaggelis , Stratakis Nikolaos , Lebentakou Vassiliki , Karachaliou Mariana , Vassilaki Maria , Kogevinas Manolis
Published: February 2012

Objective

To investigate whether high doses of folic acid supplementation in early pregnancy are associated with child neurodevelopment at 18 months of age.

Design

The study uses data from the prospective mother–child cohort ‘Rhea’ study. Pregnant women completed an interviewer-administered questionnaire on folic acid supplementation at 14–18 weeks of gestation. Neurodevelopment at 18 months was assessed with the use of the Bayley Scales of Infant and Toddler Development (3rd edition). Red-blood-cell folate concentrations in cord blood were measured in a sub-sample of the study population (n 58).

Setting

Heraklion, Crete, Greece, 2007–2010.

Subjects

Five hundred and fifty-three mother–child pairs participating in the ‘Rhea’ cohort.

Results

Sixty-eight per cent of the study participants reported high doses of supplemental folic acid use (5 mg/d), while 24 % reported excessive doses of folic acid (>5 mg/d) in early pregnancy. Compared with non-users, daily intake of 5 mg supplemental folic acid was associated with a 5-unit increase on the scale of receptive communication and a 3·5-unit increase on the scale of expressive communication. Doses of folic acid supplementation higher than 5 mg/d were not associated with additional increase in the neurodevelopmental scales.

Conclusions

This is the first prospective study showing that high doses of supplementary folic acid in early pregnancy may be associated with enhanced vocabulary development, communicational skills and verbal comprehension at 18 months of age. Additional longitudinal studies and trials are needed to confirm these results.
Alterations in the Fat Body Cells ofRhinocricus padbergi(Diplopoda) Resulting from Exposure to Substrate Containing Sewage Sludge
Authors: de Souza Raphael Bastão , Fontanetti Carmem Silvia
Published: February 2012

The final disposal of residues generated at sewage treatment plants (STPs) has become a major problem for cities, due to the increase in the amount of treated sewage. One of the alternatives for the residue, labeled “sewage sludge,” is its reuse in agriculture and in degraded soil. However, not all pathogens and metals present in it are eliminated during treatment. Diplopods have been used as bioindicators in ecotoxicological tests as they are constantly in close contact with the soil. Owing to this fact, the purpose of this study was to expose specimens of the diplopodRhinocricus padbergito substrate containing sewage sludge collected at STPs to analyze morphological alterations in their parietal and perivisceral fat body, where substances are stored. The exposures were held for 7, 15, or 90 days at different concentrations of sewage sludge (control, 1%, 10%, and 50%). The parietal fat body showed no alterations in any of the three exposure periods or concentrations. Alterations in the perivisceral fat body were observed for all exposure periods. According to the results, we suggest that the sludge used has toxic agents responsible for changing the animal's perivisceral fat body.
Intrinsic Emotional Relevance of Outcomes and Prediction Error
Authors: Nahum Louis , Barcellona-Lehmann Sandra , Morand Stéphanie , Sander David , Schnider Armin
Published: February 2012

Infrequent events, such as unexpected absence of outcomes (prediction errors), have a detrimental effect on performance of subsequent trial in various cognitive tasks. In the present event-related potential study, we tested whether the influence of prediction error manifests itself in the early cortical processing of subsequent stimuli. Participants performed a reversal learning task in which they saw two alternating pairs of faces and indicated for each pair which one would have a declared target stimulus on its nose. The target switched to the other face after several consecutive trials with correct response, thereby inducing a prediction error, with the switch being indicated by the appearance of a disk (unexpected neutral outcome) or a spider (unexpected unpleasant outcome), depending on the condition. Results showed that after both unexpected and expected unpleasant outcomes, the amplitude of P2 decreased, while after both unexpected neutral and unpleasant outcomes, the amplitude of P1 increased on the following presentation of the pair of faces. Source localization analysis suggested that the differences mainly emanated from the cuneus and precuneus with respect to the P1 and P2 time ranges respectively. We conclude that both the intrinsic emotional relevance of outcomes and prediction error may modulate attention allocation.
Interactive Effect of Dispositional Cognitive Avoidance, Magnitude of Threat, and Response Efficacy on the Persuasive Impact of Threat Communications
Authors: Nestler Steffen , Egloff Boris
Published: February 2012

This internet study investigated the effect of individual differences in cognitive avoidance on the persuasive impact of threat communications. A total of 289 participants completed a measure of dispositional cognitive avoidance and read either a high- or a low-threat communication that provided either an effective response to reduce the threat or not. We found that cognitive avoidance did not moderate the effect of magnitude of threat when response efficacy was low. By contrast, cognitive avoidance was relevant when efficacy was high: After a high-threat message, low cognitive avoiders reported more favorable attitudes toward and intentions to adopt the action recommendation than high cognitive avoiders. Further analyses showed that severity perceptions mediate this effect of avoidance on attitudes and intentions. Individual differences in cognitive avoidance are thus an important moderator of the effectiveness of threat communications.
Theory for dynamic longitudinal dispersion in fractures and rivers with Poiseuille flow
Authors: Wang Lichun , Cardenas M. Bayani , Deng Wen , Bennett Philip C.
Published: February 2012

We present a theory for dynamic longitudinal dispersion coefficient (D) for transport by Poiseuille flow, the foundation for models of many natural systems, such as in fractures or rivers. Our theory describes the mixing and spreading process from molecular diffusion, through anomalous transport, and until Taylor dispersion. D is a sixth order function of fracture aperture (b) or river width (W). The time (T) and length (L) scales that separate preasymptotic and asymptotic dispersive transport behavior are T = b2/(4Dm), where Dm is the molecular diffusion coefficient, and L =
, where p is pressure and μ is viscosity. In the case of some major rivers, we found that L is ∼150W. Therefore, transport has to occur over a relatively long domain or long time for the classical advection‐dispersion equation to be valid.
An experimental study of the brittle‐ductile transition of basalt at oceanic crust pressure and temperature conditions
Authors: Violay Marie , Gibert Benoit , Mainprice David , Evans Brian , Dautria Jean‐Marie , Azais Pierre , Pezard Philippe
Published: February 2012

The brittle to ductile transition (BDT) in rocks may strongly influence their transport properties (i.e., permeability, porosity topology…) and the maximum depth and temperature where hydrothermal fluids may circulate. To examine this transition in the context of Icelandic crust, we conducted deformation experiments on a glassy basalt (GB) and a glass‐free basalt (GFB) under oceanic crust conditions. Mechanical and micro‐structural observations at a constant strain rate of 10−5 s−1 and at confining pressure of 100–300 MPa indicate that the rocks are brittle and dilatant up to 700–800°C. At higher temperatures and effective pressures the deformation mode becomes macroscopically ductile, i.e., deformation is distributed throughout the sample and no localized shear rupture plane develops. The presence of glass is a key component reducing the sample strength and lowering the pressure of the BDT. In the brittle field, strength is consistent with a Mohr‐Coulomb failure criterion with an internal coefficient of friction of 0.42 for both samples. In the ductile field, strength is strain rate‐ and temperature‐dependent and both samples were characterized by the same stress exponent in the range 3 < n < 4.2 but by very different activation energy QGB = 59 ± 15 KJ/mol and QGFB = 456 ± 4 KJ/mol. Extrapolation of these results to the Iceland oceanic crust conditions predicts a BDT at ∼100°C for a glassy basalt, whereas the BDT might occur in non‐glassy basalts at deeper conditions, i.e., temperatures higher than 550 ± 100°C, in agreement with the Icelandic seismogenic zone.
Diurnal variation of rainfall in the Yangtze River Valley during the spring‐summer transition from TRMM measurements
Authors: Chen Guixing , Sha Weiming , Iwasaki Toshiki , Ueno Kenichi
Published: February 2012

A 12 year archive of the Tropical Rainfall Measuring Mission (TRMM) rain rate is used to document the regionality of diurnal rainfall cycle in the Yangtze River Valley (YRV). The regional rain peaks, local phase shifts, rain event's behavior, and related seasonal change from March to August are examined. In the middle reach of YRV, rainfall appears mainly in early morning and displays a distinct local shift of diurnal phase. Such features are well established at each presummer (from May to June) and result from the eastward migrating events with a late night growth in size. They are supported by the low‐level convergence that moves from the east slope of the Tibetan Plateau to the middle reach of YRV, as the deviated wind vector rotates clockwise to enhance southerlies at late night and southwesterlies in the morning. In the lower reach of YRV, however, one observes an eruption of morning rainfall with less local difference in diurnal phase. Morning rainfall is active in presummers of some years but suppressed in some others, contributing greatly to the variance of rainfall budget and resulting in anomalous wet/dry seasons. It is found to arise from a local growth of rain events rather than the migrating events from the middle reach. A majority of these organized convections prefer to form and develop in a belt‐shaped zone where the nocturnal southwesterlies of warm/moist air impinge on the Meiyu front in the lower troposphere.
Continuous in situ measurements of stable isotopes in liquid water
Authors: Herbstritt Barbara , Gralher Benjamin , Weiler Markus
Published: February 2012

We developed a method to measure in situ the isotopic composition of liquid water with minimal supervision and, most important, with a temporal resolution of less than a minute. For this purpose a microporous hydrophobic membrane contactor (Membrana) was combined with an isotope laser spectrometer (Picarro). The contactor, originally designed for degassing liquids, was used with N2 as a carrier gas in order to transform a small fraction of liquid water to water vapor. The generated water vapor was then analyzed continuously by the Picarro analyzer. To prove the membrane's applicability, we determined the specific isotope fractionation factor for the phase change through the contactor's membrane across an extended temperature range (8°C–21°C) and with different waters of known isotopic compositions. This fractionation factor is needed to subsequently derive the liquid water isotope ratio from the measured water vapor isotope ratios. The system was tested with a soil column experiment, where the isotope values derived with the new method corresponded well (R2 = 0.998 for δ18O and R2 = 0.997 for δ2H) with those of liquid water samples taken simultaneously and analyzed with a conventional method (cavity ring‐down spectroscopy). The new method supersedes taking liquid samples and employs only relatively cheap and readily available components. This makes it a relatively inexpensive, fast, user‐friendly, and easily reproducible method. It can be applied in both the field and laboratory wherever a water vapor isotope analyzer can be run and whenever real‐time isotope data of liquid water are required at high temporal resolution.
Nano N-TiO2 mediated selective photocatalytic synthesis of quinaldines from nitrobenzenes
Authors: Selvam Kaliyamoorthy , Swaminathan Meenakshisundaram
Published: February 2012

N-Doped TiO2 using a new nitrogen precursor hydrazine hydrate was synthesized by a simple wet method.
Insulation and diffusion barrier characteristics of spin-on-glass layer on a stainless steel substrate
Authors: Jeng Ming-Jer , Lai Wei-Jer , Chang Bai-Zong , Hu Sung-Cheng
Published: February 2012

The efficiency of CIGS (Copper Indium Gallium diSelenide) solar cells fabricated on stainless steel foil is lower than that on soda-lime glass substrates due to the lack of sodium incorporation and metal impurity diffusion. A dielectric barrier is necessary to prevent metal impurity diffusion for stainless steel substrates. Spin-on-glass (SOG) coatings are characterized by their lower cost and larger area than other vacuum deposition methods. By using spin coating SOG to deposit SiOx barrier layers, this study investigates the characteristics of their insulation and impurity barrier. For insulation property, a higher curing temperature is preferred. The insulation does not further improve when the curing temperature exceeds 400 °C. The SiOx film resistance can be as high as 108 Ω when the voltage is smaller than 10 V. For impurity barrier characteristics, although thick thickness is preferred, it easily incurs thermal cracking. To effectively barricade metal impurity diffusion, the influence of SiOx thickness is larger than that of curing SOG temperature.
Off-line ionization tests using the surface and the plasma ion sources of the SPES project
Authors: Manzolaro M. , Manente M. , Curreli D. , Vasquez J. , Montano J. , Andrighetto A. , Scarpa D. , Meneghetti G. , Pavarin D.
Published: February 2012

The development of new target ion source systems for the selective production of exotic species (SPES) facility is currently in progress at Legnaro National Laboratories. In this context, the study of ion sources and their performance in terms of ionization efficiency and transversal emittance is a crucial point in order to maximize the available yields, particularly for short-lived isotopes. In this work, preliminary off-line ionization efficiency and emittance measurements for the SPES surface and plasma ion sources are presented. The plasma source emittance measurements are supported by dedicated numerical calculations.
Target normal sheath acceleration analytical modeling, comparative study and developments
Authors: Perego C. , Batani D. , Zani A. , Passoni M.
Published: February 2012

Ultra-intense laser interaction with solid targets appears to be an extremely promising technique to accelerate ions up to several MeV, producing beams that exhibit interesting properties for many foreseen applications. Nowadays, most of all the published experimental results can be theoretically explained in the framework of the target normal sheath acceleration (TNSA) mechanism proposed by Wilks et al. [Phys. Plasmas 8(2), 542 (2001)10.1063/1.1333697]. As an alternative to numerical simulation various analytical or semi-analytical TNSA models have been published in the latest years, each of them trying to provide predictions for some of the ion beam features, given the initial laser and target parameters. However, the problem of developing a reliable model for the TNSA process is still open, which is why the purpose of this work is to enlighten the present situation of TNSA modeling and experimental results, by means of a quantitative comparison between measurements and theoretical predictions of the maximum ion energy. Moreover, in the light of such an analysis, some indications for the future development of the model proposed by Passoni and Lontano [Phys. Plasmas 13(4), 042102 (2006)10.1063/1.2184067] are then presented.
Electrodeposition of stoichiometric CdTe thin film for photovoltaic application
Authors: Ueng H. Y. , Yang S. Y.
Published: February 2012

Theoretical model based on the Buler-Volmer equation was developed to obtain the potential of perfect stoichiometry (PPS) under a variety of deposited conditions, and results were confirmed experimentally. It also shows that the stoichiometric deviation of CdTe thin film can be controlled accurately. The simulation of electrodeposited process for CdTe was conditioned in the acidic electrolyte containing reducible ions of Cd2+ and HTeO2+. Based on the simulated predictions, well-connected granular CdTe thin films were deposited at PPS. Due to near stoichiometric sample shows slightly p-type, the concentration of HTeO2+ ion was then decrease to reach more intrinsic condition under the PPS applied. Particularly, the p-type, near i-type and n type of CdTe thin films can be electrodeposited se-quentially. The thickness of each layers deposited was achieved by varying the applied potential with different deposited time.
Multiferroic properties of La-doped Bi2FeCrO6 prepared by high-pressure synthesis
Authors: Bai Feiming , Shi Lei , Zhang Huaiwu , Zhong Zhiyong , Wang Wendan , He Duanwei
Published: February 2012

Undoped Bi2FeCrO6 and 10 at. % La-doped Bi2FeCrO6 were prepared by a high-pressure solid-state sintering method. The phase structure, electrical, ferroelectric, and magnetic properties have been investigated. It is shown that doping La can increase the resistivity by three orders of magnitude at room temperature. Furthermore, La-doped Bi2FeCrO6 shows an enhanced magnetization, about three times that of undoped Bi2FeCrO6, and a high coercivity of ∼210 Oe.
Magnetocaloric effect in La0.5Pr0.5Fe11.5Si1.5 compounds with a combined addition of Co and C
Authors: Shen Jun , Zhao Jin-Liang
Published: February 2012

The influence of a combined addition of Co and C on the magnetocaloric effect in the La0.5Pr0.5Fe11.5Si1.5 compound is investigated. The addition of Co and C can adjust Curie temperature (TC) to around room temperature. Although the magnetic entropy change (ΔSM) of La0.5Pr0.5Fe11.5−xCoxSi1.5C0.2 decreases with the increase of x, the maximum hysteresis loss at TC reduces remarkably from 23.6 J/kg for x = 0 to close to zero for x = 0.2. For x = 0.8, the maximum value of ΔSM is −11.6 J/kg K with an RC value of 386 J/kg around TC = 295 K for a magnetic field change of 0-5 T. Our result reveals that a large ΔSM and a small hysteresis loss can be simultaneously achieved in NaZn13-type LaPrFeSi compounds with a combined addition of Co and C.
Spectral reflectance switching of colloidal photonic crystal structure composed of positively charged TiO2 nanoparticles
Authors: Shim HongShik , Lim Joohyun , Gyun Shin Chang , Jeon Seog-Jin , Gyu Han Moon , Lee Jin-Kyu
Published: February 2012

We report the tunable photonic crystal behavior of highly concentrated, mildly charged TiO2 nanoparticle colloids under external electric field. Reflectance intensity change at the certain photonic bandgap and its irreversible switching characteristics are observed and discussed. Through computer aided numerical analysis, gradient spacing between charged particles is predicted under electric field, which is well coincidence with experimental results. Also, we report the experimental evidence that the charged nanoparticle can play the role as a major charge carrier in non-aqueous liquid. Its short range moving and stacking on electrode cause the capacitive current flow and charge accumulation like ions in liquid state.
Remote lasing in air by recombination and electron impact excitation of molecular nitrogen
Authors: Peñano Joseph , Sprangle Phillip , Hafizi Bahman , Gordon Daniel , Fernsler Richard , Scully Marlan
Published: February 2012

We analyze and simulate the physical mechanisms for a remote atmospheric lasing configuration which utilizes a combination of an ultrashort pulse laser to form a plasma filament of seed electrons, and a heater beam to heat the seed electrons. Nitrogen molecules are excited by electron impact and recombination processes to induce lasing in the ultraviolet. Recombination excitation, thermal excitation, gain, and saturation are analyzed and simulated. The lasing gain is sufficiently high to reach saturation within the length of the plasma filament. A remotely generated ultraviolet source may have applications for standoff detection of biological and chemical agents.
Ab initio investigations of phonons and superconductivity in the cubic Laves structures LaAl2 and YAl2
Authors: Duman S. , Tütüncü H. M.
Published: February 2012

We have performed an ab initio study of structural, elastic, electronic, lattice-dynamical, and electron-phonon interaction properties of the cubic Laves structures LaAl2 and YAl2. The calculations have been carried out within the density-functional theory and linear response formalism using pseudopotentials and a plane-wave basis. The calculated phonon dispersion relations for both materials accord very well with experimental data available for the principal symmetry directions. The average electron-phonon coupling constant λ is found to be 0.35 for YAl2 and 0.65 for LaAl2. Thus, our results indicate the superconducting transition temperature is very low for YAl2 but a superconducting transition temperature Tc of around 3 K for LaAl2 is found with μ* = 0.16. Finally, we have observed that the soft phonon modes related to the vibrations of La atoms play a dominant role in the superconductivity of LaAl2.
Observation of collision and oscillation of microdroplets with extremely large shear deformation
Authors: Yamada Tatsuya , Sakai Keiji
Published: February 2012

We measured the viscosity and surface tension of various liquids under large (∼106 s−1) shear deformation. Oscillation of a 10-μm size microdroplet is brought about by the head-on collision of two droplets. Since the Reynolds number is as small as 100, the motion of the liquid is stable and the dynamic image is obtained with high reproducibility by the stroboscopic method. By observing and evaluating the mechanical oscillation of the microdroplet, of which frequency ranges typically in 100 – 300 kHz, we found that the viscosity of ethylene glycol and diethylene glycol is smaller than the known literature value, which is considered to be the viscosity at zero-frequency. This phenomena can be attributed to the slow viscous relaxation of associated liquids due to the re-combination dynamics of the network of H-bonds.
Length dependence of the resistance in graphite: Influence of ballistic transport
Authors: Esquinazi P. , Barzola-Quiquia J. , Dusari S. , García N.
Published: February 2012

Using a linear array of voltage electrodes with a separation of several micrometers on a 20 nm thick and 30 μm long multigraphene sample, we show that the measured resistance does not follow the usual length dependence according to Ohm’s law. The deviations can be quantitatively explained taking into account Sharvin-Knudsen formula for ballistic transport. This allows us to obtain without free parameters the mean free path of the carriers in the sample at different temperatures. In agreement with recently reported values obtained with a different experimental method, we obtain that the carrier mean free path is of the order of ∼2 μm with a mobility μ ∼ 107 cm2V−1 s−1. The results indicate that the usual Ohm’s law is not adequate to calculate the absolute resistivity of mesoscopic graphite samples.
Gas-phase structures of neutral silicon clusters
Authors: Haertelt Marko , Lyon Jonathan T. , Claes Pieterjan , de Haeck Jorg , Lievens Peter , Fielicke André
Published: February 2012

Vibrational spectra of neutral silicon clusters Sin, in the size range of n = 6–10 and for n = 15, have been measured in the gas phase by two fundamentally different IR spectroscopic methods. Silicon clusters composed of 8, 9, and 15 atoms have been studied by IR multiple photon dissociation spectroscopy of a cluster-xenon complex, while clusters containing 6, 7, 9, and 10 atoms have been studied by a tunable IR-UV two-color ionization scheme. Comparison of both methods is possible for the Si9 cluster. By using density functional theory, an identification of the experimentally observed neutral cluster structures is possible, and the effect of charge on the structure of neutrals and cations, which have been previously studied via IR multiple photon dissociation, can be investigated. Whereas the structures of small clusters are based on bipyramidal motifs, a trigonal prism as central unit is found in larger clusters. Bond weakening due to the loss of an electron leads to a major structural change between neutral and cationic Si8.
Time-resolved simultaneous polarized and depolarized light scattering system with high sensitivity to optical anisotropy: Application to phase separation of an optically isotropic liquid mixture
Authors: Koyama Takehito , Tanaka Hajime
Published: February 2012

Depolarized light scattering is widely used to probe the spatial correlation of optical anisotropy in crystals, liquid crystals, and viscoelastic materials under stress, and a powerful means to study a non-equilibrium pattern evolution process of such a system. To follow the temporal change in the diagonal and off-diagonal contributions of the dielectric tensor, it is highly desirable to measure two-dimensional (2D) polarized (HH: horizontally transmitted, horizontally received) and depolarized (VH: vertically transmitted, horizontally received) scattering patterns simultaneously in a time-resolved manner. We develop a light scattering system with a video-rate time resolution as well as very high sensitivity to optical anisotropy. To detect extremely weak VH scattering from a sample without suffering from residual birefringence of the optical system itself and leakage of strong HH scattering signals, we use an objective lens specially designed for polarizing microscopy and Glan-laser prisms, respectively. This system enables us to experimentally elucidate the origin of VH scattering: we use the ratio of the VH and HH scattering intensity as a fingerprint for whether a 2D VH scattering pattern is caused by (i) optical anisotropy (intrinsic birefringence) or merely by (ii) spatial inhomogeneity of optically isotropic materials. We verify the validity of this method for a process of phase separation in a binary mixture of isotropic liquids. The simultaneous HH and VH measurement allows us to directly estimate the ratio of VH and HH scattering intensity accurately. The careful comparison of this ratio with a simple theory unambiguously demonstrates that the 2D VH scattering pattern is caused by the scattering angle dependence of the diffraction efficiency of light with the two polarization directions. That is, the origin of VH scattering is due to geometrical effects of the inhomogeneous distribution of the refractive index and not due to optical birefringence, as it should be for the optically isotropic sample. This method using the ratio of VH and HH scattering intensity may be widely used for distinguishing the two types of origins for a VH scattering pattern in an unambiguous manner.
Diffusion of Nd-rich phase in the spark plasma sintered and hot deformed nanocrystalline NdFeB magnets
Authors: Huang Y. L. , Liu Z. W. , Zhong X. C. , Yu H. Y. , Gao X. X. , Zhu J. , Zeng D. C.
Published: February 2012

The role of the Nd-rich phase in developing microstructure and properties of isotropic and anisotropic NdFeB magnets has been investigated. Melt spun Nd-rich Nd13.5Fe73.5Co6.7Ga0.5B5.6 and Fe-rich Nd7.7Pr2.6Fe84.1B5.5 alloy powders were mechanically mixed with different ratios. The mixed powders were consolidated into isotropic magnets and anisotropic magnets by spark plasma sintering (SPS) and SPS followed by hot deformation, respectively. The composition and microstructure of diffusion area between Nd-rich and Fe-rich compositions for isotropic and anisotropic magnets were investigated. The gradient distribution of Nd content from Nd-rich to Fe-rich area due to the diffusion of liquid Nd-rich phase in the SPS and hot deformation was observed, which leads to gradually changes in grain structure. The remanent polarization of 1.29 T, coercivity of 995 kA/m, and maximum energy product of 293 kJ/m3 are obtained for an anisotropic magnet. The role of the Nd-rich phase has to be carefully considered in order to achieve deformation anisotropy and fine grains in the NdFeB magnets.
Piezoelectric 36-shear mode for [011] poled 24%Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ferroelectric crystal
Authors: Yan Weiling , Han Pengdi , Jiang Zibo
Published: February 2012

Superior piezoelectric 36-shear mode of [011] poled Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) in zxt+/−45o cut direction is the first practical piezoelectric 36-shear mode reported [P. Han, “Piezoelectric crystal elements of shear mode and process for preparation,” U.S. patent 7,908,722 B2 (2004)]. The investigation on the piezoelectric 36-shear mode of PIN-PMN-PT crystal was carried out and summarized in this paper. The [011] poled 24%Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) crystal was chosen for the study owing to its large coercive electrical field and high de-poling temperature. Following an introduction to the concept of the piezoelectric 36-shear mode and targeting to explore the maximum d36, we have performed the theoretical calculation on d36 by coordinate transformation of a third rank tensor. To verify the results of the calculation, the d36 was measured by two ways: strain measurements (piezoelectric converse effect) and charge measurements (piezoelectric direct effect) on the same composition crystal. It has been distinguished and determined that the maximum d36 piezoelectric coefficients occurred in the zxt + 45o cut direction for negative and in the zxt−45o cut direction for positive, respectively. The electromechanical coupling factor k36 was also studied. The occurrence of the maximum d36 up to 2400 pC/N and the large electromechanical coupling factor k36 as high as 87.8% were theoretically and experimentally confirmed on zxt ± 45o cut, [011] poled 24%PIN-PMN-PT piezoelectric crystals. The 36-shear mode PIN-PMN-PT crystal enables the piezoelectric performance under high electrical field driving.
The role of surface defects in multi-exciton generation of lead selenide and silicon semiconductor quantum dots
Authors: Jaeger Heather M. , Fischer Sean , Prezhdo Oleg V.
Published: February 2012

Multi-exciton generation (MEG), the creation of more than one electron-hole pair per photon absorbed, occurs for excitation energies greater than twice the bandgap (Eg). Imperfections on the surface of quantum dots, in the form of atomic vacancies or incomplete surface passivation, lead to less than ideal efficiencies for MEG in semiconductor quantum dots. The energetic onset for MEG is computed with and without surface defects for nanocrystals, Pb4Se4, Si7, and Si7H2. Modeling the correlated motion of two electrons across the bandgap requires a theoretical approach that incorporates many-body effects, such as post-Hartree-Fock quantum chemical methods. We use symmetry-adapted cluster with configuration interaction to study the excited states of nanocrystals and to determine the energetic threshold of MEG. Under laboratory conditions, lead selenide nanocrystals produce multi-excitons at excitation energies of 3 Eg, which is attributed to the large dielectric constant, small Coulomb interaction, and surface defects. In the absence of surface defects the MEG threshold is computed to be 2.6 Eg. For lead selenide nanocrystals with non-bonding selenium valence electrons, Pb3Se4, the MEG threshold increases to 2.9 Eg. Experimental evidence of MEG in passivated silicon quantum dots places the onset of MEG at 2.4 Eg. Our calculations show that the lowest multi-exciton state has an excitation energy of 2.5 Eg, and surface passivation enhances the optical activity of MEG. However, incomplete surface passivation resulting in a neutral radical on the surface drives the MEG threshold to 4.4 Eg. Investigating the mechanism of MEG at the atomistic level provides explanations for experimental discrepancies and suggests ideal materials for photovoltaic conversion.
First principles analysis of the initial oxidation of Si(001) and Si(111) surfaces terminated with H and CH3
Authors: Li Huashan , Lin Zhibin , Wu Zhigang , Lusk Mark T.
Published: February 2012

Transition state analyses have been carried out within a density functional theory setting to explain and quantify the distinctly different ways in which hydrogen and methyl terminations serve to protect silicon surfaces from the earliest onset of oxidation. We find that oxidation occurs via direct dissociative adsorption, without any energy barrier, on Si(111) and reconstructed Si(001) that have been hydrogen terminated; oxidation initiates with a barrier of only 0.05 eV on unreconstructed Si(001). The commonly measured protection afforded by hydrogen is shown to derive from a coverage-dependent dissociation rate combined with barriers to the hopping of adsorbed oxygen atoms. Methyl termination, in contrast, offers an additional level of protection because oxygen must first undergo interactions with these ligands in a three-step process with significant energy barriers: adsorption of O2 into a C–H bond to form a C–O–O–H intermediate; decomposition of C–O–O–H into C–O–H and C=O intermediates; and, finally, hopping of oxygen atoms from ligands to the substrate.
A first-principles density functional theory study of the electronic structural and thermodynamic properties of M2ZrO3 and M2CO3 (M = Na, K) and their capabilities for CO2 capture
Authors: Duan Yuhua
Published: February 2012

Alkali metal zirconates could be used as solid sorbents for CO2 capture. The structural, electronic, and phonon properties of Na2ZrO3, K2ZrO3, Na2CO3, and K2CO3 are investigated by combining the density functional theory with lattice phonon dynamics. The thermodynamics of CO2 absorption/desorption reactions of these two zirconates are analyzed. The calculated results show that their optimized structures are in a good agreement with experimental measurements. The calculated band gaps are 4.339 eV (indirect), 3.641 eV (direct), 3.935 eV (indirect), and 3.697 eV (direct) for Na2ZrO3, K2ZrO3, Na2CO3, and K2CO3, respectively. The calculated phonon dispersions and phonon density of states for M2ZrO3 and M2CO3 (M = K, Na, Li) revealed that from K to Na to Li, their frequency peaks are shifted to high frequencies due to the molecular weight decreased from K to Li. From the calculated reaction heats and relationships of free energy change versus temperatures and CO2 pressures of the M2ZrO3 (M = K, Na, Li) reacting with CO2, we found that the performance of Na2ZrO3 capturing CO2 is similar to that of Li2ZrO3 and is better than that of K2ZrO3. Therefore, Na2ZrO3 and Li2ZrO3 are good candidates of high temperature CO2 sorbents and could be used for post-combustion CO2 capture technologies.
Local structure of nitrogen in N-doped amorphous and crystalline GeTe
Authors: Kolobov Alexander V. , Fons Paul , Hyot Bérangère , André Bernard , Tominaga Junji , Tamenori Yusuke , Yoshikawa Hideki , Kobayashi Keisuke
Published: February 2012

The local structure around nitrogen species in N-doped GeTe has been investigated using (soft) x-ray absorption spectroscopy and high-resolution x-ray photoemission spectroscopy. The obtained results demonstrate that while in as-deposited amorphous GeTe nitrogen is predominantly bonded to Ge atoms, upon crystallization the majority of nitrogen forms N2 molecules that are likely to be located in the grain boundaries, with only a small fraction of nitrogen species remaining bonded to Ge.
Resonant magnetic response of TiO2 microspheres at terahertz frequencies
Authors: Němec H. , Kadlec C. , Kadlec F. , Kužel P. , Yahiaoui R. , Chung U.-C. , Elissalde C. , Maglione M. , Mounaix P.
Published: February 2012

Spray-drying technique is used to fabricate spherical microparticles out of dissolved TiO2 nanoparticles. We show both experimentally and through numerical calculations that the microspheres support a Mie resonance, leading to an effective magnetic response. For this purpose, nearly single layers of microspheres were prepared and characterized by time-domain terahertz spectroscopy. We developed an experimental approach allowing simultaneous measurement of complex transmittance and reflectance of a thin layer, which in turn enables evaluation of its effective dielectric permittivity and effective magnetic permeability. Numerical finite-element-method calculations of the electromagnetic response show that the prepared microparticles are suitable for preparing a metamaterial with negative effective magnetic permeability.
Characterization of cluster/monomer ratio in pulsed supersonic gas jets
Authors: Gao X. , Wang X. , Shim B. , Arefiev A. V. , Korzekwa R. , Downer M. C.
Published: February 2012

We determine cluster mass fraction fc(r,t) at position r within, and time t after firing, a pulsed supersonic gas jet by measuring femtosecond evolution of the jet’s refractive index by single-shot frequency domain holography. A fs pump pulse singly ionizes monomers, while quasi-statically ionizing and heating clusters to a level at which recombination remains negligible as clusters expand. Under these conditions, index evolves in two simple steps corresponding to monomer and cluster contributions, allowing recovery of fc without detailed cluster dynamic modeling. Variations of fc with t are measured.
Dynamic hysteresis of tetragonal ferroelectrics: The resonance of 90°-domain switching
Authors: Chen D. P. , Liu J.-M.
Published: February 2012

The dynamic hysteresis of ferroelectric lattice with 90°-domain structure in response to time-varying electric field of frequency ω and amplitude E0 is investigated using Monte Carlo simulation based on the Ginzburg-Landau phenomenological theory. A resonance mode of the polarization switching at low frequency range, associated with cluster dipole switching, beside the dipole switching resonance mode, is revealed, characterized by two separate peaks in the hysteresis area spectrum A(ω). It is indicated that the power law scaling behaviors A(ω) ∼ ωα for ω → 0 and A(ω) ∼ ω−β for ω → ∞ remain applicable.
InGaN light-emitting diodes with indium-tin-oxide sub-micron lenses patterned by nanosphere lithography
Authors: Zhang Q. , Li K. H. , Choi H. W.
Published: February 2012

Close-packed micro-lenses with dimensions of the order of wavelength have been integrated onto the indium-tin-oxide (ITO) layer of GaN light-emitting diodes employing nanosphere lithography. The ITO lens arrays are transferred from a self-assembled silica nanosphere array by dry etching, leaving the semiconductor layer damage-free. An enhancement of up to 63.5% on optical output power from the lensed light-emitting diode (LED) has been observed. Lens-patterned LEDs are also found to exhibit reduced emission divergence. Three-dimensional finite-difference time-domain simulations performed for light extraction and emission characteristics are found to be consistent with the observed results.
Universal for whom? Evaluating an urban Aboriginal population's access to a mainstream universal health home visiting program
Authors: Widdup John , Comino Elizabeth J. , Webster Vana , Knight Jennifer
Published: February 2012

Objective.
To investigate access to a Universal Health Home Visit program for families of Aboriginal and non-Aboriginal infants and the effect of a one-off home visit on subsequent health service utilisation.

Methods.
A case-control study was undertaken drawing 175 Aboriginal infants from an Aboriginal birth cohort study and 352 matched non-Aboriginal infants. A structured file audit extracted data from child and family health nurse records. Receipt of home visit and effect on ongoing use of child and family nurses services was compared for Aboriginal and non-Aboriginal infants.

Results.
Of the 527 infants, 279 (53.0%) were visited at home within 2 weeks. This is below NSW Health benchmarks. Significantly fewer Aboriginal infants (42.9%) compared to non-Aboriginal infants (58.0%) received a home visit within 2 weeks (P < 0.01). Receipt of a single home visit did not affect future service use or the number of child health checks infants received.

Conclusion.
This study highlights the challenges of ensuring equitable access to a universal post-natal home visiting program. Assessing ways in which universal services are delivered to ensure equity of access may help to re-evaluate target expectations, reduce demand on nursing staff, improve targeting of vulnerable infants and help in further developing and implementing effective health policy.

What is known about the topic?
The rate of home visits within NSW is 45%, which is well below the recommended target rate of 65%. Aboriginal families utilise health services differently than non-Aboriginal families.

What does this paper add?
Inequalities in accessing a home visit within 2 weeks were found, with families of Aboriginal infants being less likely than families of non-Aboriginal infants to receive a home visit within 2 weeks. Factors such as being a young mother, an unpartnered mother, a mother with psychosocial risks identified antenatally, or residing in a disadvantaged suburb were associated with not receiving a visit within 2 weeks. Receipt of a home visit did not, despite the program’s aim, affect further health service use.

What are the implications for practitioners?
Practitioners and managers need to be aware of the challenges in providing equitable access within a universal post-natal home visiting program.
Identifying intimate partner violence when screening for health and lifestyle issues among women attending general practice
Authors: Hegarty Kelsey L. , O'Doherty Lorna , Astbury Jill , Gunn Jane
Published: February 2012

Intimate partner violence is a common but under-recognised issue for women attending primary care. There is a lack of studies looking at women’s comfort to discuss and openness to getting help for health issues, including fear of a partner, in primary care. Female patients (aged 16–50 years) attending 55 general practitioners (GPs) in Victoria, Australia were mailed a brief survey that screened for health and lifestyle issues, comfort to discuss these issues and intention to get help in primary care. Needing physical activity and smoking were the issues women were most comfortable to discuss; followed by difficulty controlling what and/or how much is eaten, feeling down, depressed, hopeless or worried, and use of drugs or alcohol. Women were least comfortable to discuss fear of a partner and least likely to seek help for it from the GP or primary care nurse. However, as with the other issues, acceptability of being asked in a survey was high. All health and lifestyle issues predicted fear of a partner. Primary care practitioners should be aware of this complex major public health issue especially when carrying out preventive health care.