bluuebunny/crossref_metadata_2025 huggingface dataset:
Exposure to maternal consumption of cafeteria diet during the lactation period programmes feeding behaviour in the rat
Authors: Wright Thomas M. , Fone Kevin C.F. , Langley‐Evans Simon C. , Voigt Jörg‐Peter W.
Published: October 2011

Lactational overfeeding programmes obesity in the adult rat, and also impacts on adult emotional behaviour. The present study investigated the impact of exposing the lactating female to a hypercaloric diet on structural aspects of feeding behaviour in the adult offspring as measured by the behavioural satiety sequence (BSS). Lactating Wistar rats were fed a hypercaloric cafeteria diet (CD) in addition to chow. Controls were fed on chow only. All offspring were chow fed after weaning. BSS was tested in 12–15 week old offspring. At 20 weeks of age, monoamine neurotransmitter levels were measured in selected brain regions. When exposed to a palatable 1‐h test meal, offspring responded with the same latency to feed, regardless of lactational diet. Total food intake during the test was unaffected by lactational diet. Control offspring showed a normal BSS pattern. Male CD offspring displayed shorter feeding bouts (P < 0.05) with an overall higher bout frequency (P < 0.001) and their latency to rest was delayed (P < 0.001). Overall eating frequency (P < 0.05), but not duration was increased in male CD offspring. Although the transition from feeding to resting was not affected by lactational CD, CD males fed for longer at the beginning of the test meal and were more active towards the end. CD females displayed an increased number of feeding bouts (P < 0.05) and they spent more time eating (P < 0.05). Resting latency was delayed (P < 0.05) and overall time spent resting was shortened (P < 0.01). Frequency of eating was increased in the middle of the test meal. The onset of satiety as indicated by the transition point between eating and resting was delayed in CD females (P < 0.001). In both sexes, hypothalamic 5‐hydroxytryptamine (5‐HT) was increased (P < 0.05 in females, P < 0.01 in males) and 5‐HT turnover was reduced by lactational CD (P < 0.001 in females, P < 0.01 in males). Lactational CD led also to an increase in dopamine (DA) (P < 0.01). Hypothalamic DA metabolism (DOPAC + HVA/DA ratio) was overall lower in females than in males (P < 0.01). This study indicates a programming effect of lactational CD on feeding behaviour and brain monoaminergic neurons.
When less is more: Consumer aversion to unused utility
Authors: Bolton Lisa E. , Alba Joseph W.
Published: October 2011

A series of experiments demonstrates that consumers exhibit aversion to waste during forward‐looking purchase. These experiments further reveal that such behavior is driven by distaste for unused utility, a reaction that is shown to be distinct from an aversion to squandering money. Waste aversion is especially pronounced when consumers anticipate future consequences and deprivation is salient. In addition to demonstrating robustness across consumers and marketing contexts, the results also demonstrate how waste aversion can lead to self‐defeating behavior in which consumers forego desired utility. Finally, the present research demonstrates and discusses the implications of waste aversion for a variety of marketing issues, including buy‐rent markets, bundling, and the fundamental distinction between goods and services.
The effect of leverage on the tax‐cut versus investment‐subsidy argument
Authors: Danielova Anna , Sarkar Sudipto
Published: October 2011

Two common methods of attracting corporate investment are investment incentives and tax incentives. It is important to use the two incentives in the correct proportions, otherwise the government will give up too much value in the process of attracting investment. This paper examines the effect of tax cut and investment subsidy on the government's net benefit from a project. Earlier studies concluded that it was optimal to use only investment subsidy and no tax cuts. We show that this is not true when debt financing is possible, and it is generally optimal (from the government's perspective) to use a combination of tax reduction and investment subsidy. The optimal tax rate and optimal investment subsidy are identified and analyzed in the paper. It is shown that using a sub‐optimal combination of incentives can result in substantial reduction of benefits for the government.
Improving Sleep at Altitude: A Comparison of Therapies
Authors: Rodway George W. , Edsell Mark E. , Wong Bob , Windsor Jeremy S.
Published: October 2011

Objective

This study aimed to compare 3 treatment modalities during sleep at an altitude of 5300 m to identify strategies for reducing the incidence of periodic breathing at high altitude.

Methods

Fifteen trekkers, with identical ascent profiles and no signs or symptoms of altitude illness, served as subjects. All study participants arrived at 5300 m after a gradual ascent from 1300 m. On their second night at 5300 m, subjects were randomly assigned (with a computer-based random assignment procedure) to 1 of 4 different treatment groups: control ( n = 4); 1 L/min O2 via a demand system during sleep ( n = 3); 1 L/min O2/CO2 mix (1.5% CO2) via a demand system during sleep ( n = 4); or 125 mg acetazolamide 30 minutes before bedtime ( n = 4). Heart rate, respiration rate, blood oxygen saturation, tidal volume, minute volume, and apnea hypopnea index were measured.

Results

Upon comparing the 4 groups, there were no statistically significant differences between the variables. One-way analysis of variance indicated a trend toward statistical significance for SaO2 between groups (F = 2.9, P = .08), and Tukey Honestly Significant Difference (HSD) post hoc tests indicated a trend in the SaO2 difference between the 1 L/min oxygen and control groups ( P = .07). While 1-way analysis of variance suggested no difference for respiratory rate between groups (F = 2.5, P = .1), Tukey HSD indicated a trend in statistical difference of the respiratory rate between 1 L/min O2 and 1 L/min O2/CO2 mixture ( P = .08).

Conclusions

These statistical trends found between control and treatment groups indicate that further study is warranted.
Keeping Your Cool: A Case Study of a Female Explorer's Solo North Pole Expedition
Authors: Devonport Tracey J. , Lane Andrew M. , Lloyd Juliette
Published: October 2011

Objective

This study explored stress and coping experiences during a solo expedition to the North Pole using concurrent and retrospective methods.

Methods

A 47-year-old female explorer, with 12 years of polar experience, completed a daily diary during the expedition. On return, 2 semistructured interviews were completed to identify the challenges and coping efforts perceived as being most pertinent during her expedition.

Results

Inductive coding identified 4 broad stressors, including environmental conditions, personal challenges, supporting resources, and expedition progress.

Conclusions

Findings highlight the importance of expedition preparation in establishing coping efficacy in managing the extreme demands placed upon polar explorers. Findings also evidence idiosyncrasies in the choice and application of coping strategies and, thus, highlight the need to avoid generalizations regarding coping outcomes.
Immune Responses to Exercising in a Cold Environment
Authors: LaVoy Emily C.P. , McFarlin Brian K. , Simpson Richard J.
Published: October 2011

Cold temperature and exercise independently impose stress on the human body that can lead to circulatory and metabolic changes, and depress the immune system. Multiple stressors applied together may amplify this immunodepression, causing greater immune impairment and heightened infection risk than with either stressor alone. As such, winter athletes and other persons who work or physically exert themselves in cold temperatures may have greater levels of stress-induced immune impairment than would be expected under mild temperatures. This review examines the literature regarding changes to physiological and immunological parameters arising from exposure to cold temperatures and to exercise. Even brief exposure to cold leads to increased levels of norepinephrine and cortisol, lymphocytosis, decreased lymphoproliferative responses, decreased levels of TH1 cytokines and salivary IgA, and increased lactate levels during exercise. Whether these changes lead to increased susceptibility to infection, as suggested by some epidemiological reports, remains to be determined. Although there is some evidence that exercising in temperatures near 5°C leads to greater immune impairment compared to exercising in milder temperatures, there is a need to explore the effects of exercise on immunity in the subfreezing conditions typically encountered by winter athletes. This is required to fully determine the extent to which performing vigorous exercise in subfreezing temperatures amplifies exercise-induced immune impairment and infection risk.
Boundary Conditions and Constraints of the Modality Effect
Authors: Schüler Anne , Scheiter Katharina , Schmidt-Weigand Florian
Published: October 2011

Abstract.The modality effect in multimedia learning suggests that pictures presented together with spoken text lead to better learning outcomes than pictures presented together with written text. Although the modality effect has been demonstrated in a number of empirical studies, there is an emerging body of evidence that speaks against its universal validity. Rather, it might occur only when specific boundary conditions are given. Therefore, the aim of the current special issue is to offer a platform to publish studies that contribute to identifying these possible boundary conditions. In the introduction to this special issue, firstly a context for the articles of the special issue is provided by describing in more detail the theoretical framework for the modality effect that can be used to derive different explanations for its occurrence. Secondly, because the studies reported in this special issue failed to observe the modality effect when according to the theoretical framework and the pre-existing empirical evidence a modality effect had to be expected, problems associated with interpreting null effects are discussed. Thirdly, the main findings of each of the contributing articles are discussed. Overall, the studies presented in this special issue indicate that the modality effect is not as ubiquitous as one might assume. Hence, the modality principle, that is the recommendation to use narrated rather than written multimedia presentations, should be considered with care.
Does Animation Amplify the Modality Effect – or is there any Modality Effect at All?
Authors: Schmidt-Weigand Florian
Published: October 2011

Abstract.This study aimed to examine if the modality effect is amplified by the matter of animation. Visual dynamics are suspected to increase split attention affordances due to a higher salience and transience compared to static visuals. In two experiments students watched an instruction on the formation of lightning while their eye movements were recorded. Both experiments varied text presentation (spoken, written) and visualization format (dynamic, static) in a 2x2 design. Learning outcomes were measured with verbal retention, visual retention, and transfer tests. Experiment 1 (N = 50) revealed a modality effect (i. e. better performance in spoken text groups) for visual retention but not for verbal retention and transfer. Experiment 2 (N = 60) replicated Experiment 1 with a faster presentation pace, expecting faster presentation to enlarge modality effects. In contrast, Experiment 2 revealed no modality effects in learning outcomes. In both experiments participants spent less time viewing visualizations when text was written. Within written text conditions text was read first and gained more visual attention than visualizations. Viewing time did not significantly vary between dynamic and static visualizations. Thus, animation did neither affect viewing behavior nor learning outcome. Moreover, the lack of effects in a standard manipulation of text modality cast doubts on the reliability of modality effects and, hence, on the validity of a general modality principle.
On the Robustness of the Modality ­Effect: Attempting to Replicate a Basic Finding
Authors: Lindow Stefanie , Fuchs Heather M. , Fürstenberg Anne , Kleber Janet , Schweppe Judith , Rummer Ralf
Published: October 2011

Abstract.Two experiments were conducted to replicate the modality effect and to test two opposing theoretical explanations: From the visuo-spatial load hypothesis (as implied by the Cognitive Theory of Multimedia Learning), we derived the prediction that the modality effect depends on the need to simultaneously store and process text and pictorial information in the same working memory subsystem, which implies that the modality effect is not influenced by text length. However, based on the concurrent auditory recency hypothesis, we expected the modality effect to occur with very short texts only, irrespective of whether a picture is present. Adopting a German translation of the learning materials used by Moreno and Mayer (1999) , we failed to detect a modality effect for sequential text-picture-presentation in Experiment 1. In Experiment 2, a modality effect was expected for simultaneous presentation of the same texts and pictures, yet again remained absent. We conclude with the suggestion that the apparent robustness of the modality effect reported in the literature might be explained – at least in part – by publication bias.
Does the Modality Effect in Multimedia Learning Appear only with Text Containing Spatial Information?
Authors: Schüler Anne , Scheiter Katharina , Gerjets Peter
Published: October 2011

Abstract.The current study tested the assumption that the modality effect in multimedia learning only appears when the text conveys spatial rather than non-spatial information. This assumption is based on findings from working memory research suggesting that the processing of spatial text contents and the execution of eye movements during reading may interfere with each other in visuo-spatial working memory. To test this hypothesis, 80 students were randomly assigned to four groups, resulting from a 2 × 2 design with text modality (spoken vs. written text) and text contents (visual vs. spatial) as between-subject factors. Learning outcomes were measured by means of text and picture recognition. Eye movements were recorded during learning. The results did not confirm the expected interaction between text content and text modality. In addition, the main effect of text modality effect was limited to picture recognition but did not appear for text recognition. This modality effect was mediated by the amount of concentration participants reported to have invested into studying the pictures. These results imply that the often found superiority of spoken text in multimedia learning might simply be due to a better availability of pictorial information instead of an overload of visuo-spatial working memory when processing written text.
Colorful Bouquets in Multimedia ­Research: A Closer Look at the Modality Effect
Authors: Schnotz Wolfgang
Published: October 2011

Abstract.The modality effect states that students learn better from multimedia instructional messages when the text is spoken rather than when it is written. The effect is considered as a derivate of the multimedia effect, because its rationale is to take full advantage of text-picture combinations by maximizing temporal contiguity of verbal and pictorial information in working memory and by minimizing negative effects of split attention. Accordingly, the modality effect is interrelated to other multimedia learning effects, interrelated to the degree of literacy and interrelated to research on reading comprehension and listening comprehension. The modality effect is then analyzed in terms of sensorial and cognitive processing. The sensorial facet of split attention refers to the total amount of information transferred to working memory under severely limited time constraints. The cognitive facet of split attention refers to the simultaneous availability of verbal and pictorial information in working memory as part of a fleeting database for mental model construction. Other explanations can be derived from these facets. The modality effect turns out to be not a unitary effect based on a coherent set of causal relationships. Instead, it aggregates seemingly similar observations that are in fact based on different processing mechanisms. It seems that it can easily be suspended or changed to the opposite under specific conditions.
Was bringt DSM-V?
Authors: Rief Winfried
Published: October 2011

Zusammenfassung. Das amerikanische Klassifikationssystem DSM-V wird richtungsweisenden Einfluss nicht nur auf andere Klassifikationssysteme (wie ICD-11) haben, sondern auch auf Fragen der Versorgung, auf Forschungsinitiativen und auf viele andere Aspekte der Gesellschaft. Deshalb ist eine frühzeitige Beschäftigung mit zu erwartenden Änderungen von DSM-V von besonderer Bedeutung. Beispielhaft werden fünf Vorschläge für Revisionen in DSM-V vorgestellt und diskutiert (Persönlichkeitsstörungen, Essstörungen, Schlafstörungen, somatische Symptomstörung im Allgemeinen, somatische Symptomstörung im Kindes- und Jugendalter).
Somatoforme Störungen im Kindes- und Jugendalter: ­Perspektiven für das DSM-V
Authors: Elena Ilva , Petermann Franz
Published: October 2011

Zusammenfassung. Die Validität, Reliabilität und der klinischen Nutzen der gegenwärtigen Störungskategorie der somatoformen Störungen nach dem DSM-IV-TR sind stark umstritten. Die DSM-V-Arbeitsgruppe schlägt daher eine Neustrukturierung und Umbenennung der bisherigen Störungskategorie in Somatic Symptom Disorders vor. In diesem Artikel wird analysiert, ob die Diagnosekriterien der bisherigen somatoformen Störungen nach DSM-IV-TR und die Complex Somatic Symptom Störung dazu geeignet sind, Kinder und Jugendliche zu identifizieren, die durch medizinisch unklare Symptome in ihrem Alltag und ihrer Lebensqualität beeinträchtigt sind. Besonders die Somatisierungsstörung nach DSM-IV-TR erweist sich für Kinder und Jugendliche als ungeeignet. Einschränkungen des DSM-Ansatzes in der Klassifikation von somatoformen Störungen im Kindes- und Jugendalter werden dargestellt. Studien zeigen, dass die Gesundheit der Eltern einen wesentlichen Einfluss auf die Entstehung und Aufrechterhaltung somatoformer Störungen im Kindes- und Jugendalter sowie die Inanspruchnahme des Gesundheitswesens hat. In der neueste Version der Kriterien der Complex Somatic Symptom Störung wird diese besondere Situation von Kindern/Jugendlichen beachtet; die Diagnose kann auch gestellt werden, wenn die Eltern des Kindes exzessive Gedanken, Gefühle oder Verhaltensweisen aufgrund der Symptome ihres Kindes zeigen.
Bringt DSM-V die Lösung für ­Klassifikationsprobleme bei ­Somatoformen Störungen?
Authors: Rief Winfried
Published: October 2011

Zusammenfassung. Die Gruppe der somatoformen Störungen wurde seit der Einführung mit DSM-III wiederholt kritisiert und in einigen Ländern nur unbefriedigend als Diagnose verwendet und umgesetzt. Deshalb wurden Personen mit solchen Syndromen unter einer Vielzahl anderer Diagnosen in den Gesundheitssystemen geführt, was sowohl für Forschungsprojekte und deren Vergleichbarkeit als auch für Versorgungsfragen unbefriedigend ist. Die DSM-V Work Group zur Entwicklung von neuen Vorschlägen zu dieser Patientengruppe stellt das Konzept der Somatic Symptom Disorder vor, dessen Prototyp die Complex Somatic Symptom Disorder (CSSD) ist. Dabei soll die Unterscheidung zwischen medizinisch begründeten und medizinisch nicht ausreichend begründeten körperlichen Beschwerden aufgegeben werden. Demgegenüber soll der Schwerpunkt auf psychische Begleitprobleme bei der Klassifikation der CSSD gelegt werden. Der vorliegende Beitrag diskutiert Stärken und Schwächen des neuen Vorschlags und gibt eine abschließende Bewertung.
Lebensqualität von Kindern in der ­Jugendhilfe: Welchen Einfluss besitzt die psychische Belastetheit der Kinder?
Authors: Büttner Peter , Petermann Franz , Petermann Ulrike , Rücker Stefan
Published: October 2011

Zusammenfassung. Kinder und Jugendliche in teilstationären Erziehungshilfen erreichen im SDQ zu Beginn einer Maßnahme Werte mit klinischer Bedeutsamkeit (N = 84); rund 25% berichten im ILK zudem eingeschränkte Lebensqualität. Bivariate Korrelationen zeigen deutliche Zusammenhänge zwischen den Skalen und dem Konzept der Lebensqualität. Mit Ausnahme der SDQ-Skalen Hyperaktivität und Verhaltensprobleme mit Gleichaltrigen klären die SDQ-Skalen in der Regressionsanalyse 45% der Varianz auf und erweisen sich damit prädiktiv für die Vorhersage eingeschränkter Lebensqualität. Ob sich das Konzept der Lebensqualität im Kontext der Jugendhilfe zur Qualifizierung der Maßnahmen nutzen lässt, muss sich im Längsschnitt zeigen.
Gender- und geschlechtsspezifische Aspekte in der psychiatrischen und psychotherapeutischen Forschung: eine bibliometrische Analyse
Authors: Stengler Katarina , Glaesmer Heide , Dietrich Sandra
Published: October 2011

Zusammenfassung. Inwiefern spiegeln sich geschlechtsspezifische Aspekte in der aktuellen psychiatrisch-psychotherapeutischen Forschung in Deutschland wider? Analyse aller in den Jahren 2009 und 2010 in den Zeitschriften Psychotherapeut, Psychiatrische Praxis sowie Psychotherapie · Psychosomatik · Medizinische Psychologie erschienenen Originalarbeiten. In 16 der 191 Originalarbeiten wurden geschlechtsspezifische Fragestellungen als primärer Forschungsgegenstand untersucht. Nur 3 davon befassten sich mit einer geschlechtsspezifischen/Gender-Analyse in die beide Geschlechter einbezogen wurden. Während insgesamt die Zahl der Erstautoren und Erst­autorinnen nahezu gleich war, wurden mehr als 2 Drittel (69%) der Arbeiten mit geschlechtspezifischem Forschungsgegenstand von Frauen in Erstautorenschaft publiziert. In nur einem Viertel (25%) aller Originalarbeiten wurde das Geschlecht als soziodemographische Variable in die Auswertung einbezogen. Die Betrachtung beider Geschlechter und ihrer Spezifika erweist sich dabei sowohl für die Pa­tienten- als auch für die professionelle Ebene der psychiatrisch-psychotherapeutischen Versorgung und Forschung als notwendig.
Control of spontaneous emission in a volume of functionalized hyperbolic metamaterial
Authors: Tumkur T. , Zhu G. , Black P. , Barnakov Yu. A. , Bonner C. E. , Noginov M. A.
Published: October 2011

We have developed a simple method to fabricate lamellar metal-dielectric hyperbolic metamaterials on flat, flexible, and curvilinear substrates, which allows for functionalization of dielectric layers by dye molecules. The control of spontaneous emission of dye molecules with hyperbolic metamaterials has been studied in two different sample configurations, and the effect has been found to be much stronger when emitters are placed inside the metamaterial rather than on its surface.
Kinetics of large B clusters in crystalline and preamorphized silicon
Authors: Aboy Maria , Pelaz Lourdes , Bruno Elena , Mirabella Salvo , Boninelli Simona
Published: October 2011

We present an extended model for B clustering in crystalline or in preamorphized Si and with validity under conditions below and above the equilibrium solid solubility limit of B in Si. This model includes boron-interstitial clusters (BICs) with BnIm configurations—complexes with n B atoms and m Si interstitials—larger (n > 4), and eventually more stable, than those included in previous models. In crystalline Si, the formation and dissolution pathways into large BICs configurations require high B concentration and depend on the flux of Si interstitials. In the presence of high Si interstitial flux, large BICs with a relatively large number of interstitials (m ≥ n) are formed, dissolving under relatively low thermal budgets. On the contrary, for low Si interstitial flux large BICs with few interstitials (m ≪ n) can form, which are more stable than small BICs, and whose complete dissolution requires very intense thermal budgets. We have also investigated the kinetics of large BICs in preamorphized Si, both experimentally and theoretically. B was implanted at a high-dose into preamorphized Si, and the B precipitation was studied by transmission electron microscopy and by sheet resistance and Hall measurement techniques. A simplified model for B clustering and redistribution in amorphous Si is proposed, including the experimental value for the B diffusivity in amorphous Si and the energetics of BICs. Our model suggests that B2, B3I, B4I and B4I2 clusters are the most energetically favored configurations, with relative abundance depending on B concentration. After recrystallization, thermal anneals up to 1100 °C evidence that BICs evolve under very low flux of Si interstitials under the particular experimental conditions considered. Simulations indicate that for very high B concentrations and low Si interstitial flux a significant fraction of the initial small BICs evolves into larger and very stable BIC configurations that survive even after intense thermal budgets, as confirmed by energy filtered transmission electron microscopy analyses. The correlation between simulations and Hall measurements on these samples suggest that hole mobility is significantly degraded by the presence of a high concentration of BICs.
An efficient local coupled cluster method for accurate thermochemistry of large systems
Authors: Werner Hans-Joachim , Schütz Martin
Published: October 2011

An efficient local coupled cluster method with single and double excitation operators and perturbative treatment of triple excitations [DF-LCCSD(T)] is described. All required two-electron integrals are evaluated using density fitting approximations. These have a negligible effect on the accuracy but reduce the computational effort by 1–2 orders of magnitude, as compared to standard integral-direct methods. Excitations are restricted to local subsets of non-orthogonal virtual orbitals (domain approximation). Depending on distance criteria, the correlated electron pairs are classified into strong, close, weak, and very distant pairs. Only strong pairs, which typically account for more than 90% of the correlation energy, are optimized in the LCCSD treatment. The remaining close and weak pairs are approximated by LMP2 (local second-order Møller-Plesset perturbation theory); very distant pairs are neglected. It is demonstrated that the accuracy of this scheme can be significantly improved by including the close pair LMP2 amplitudes in the LCCSD equations, as well as in the perturbative treatment of the triples excitations. Using this ansatz for the wavefunction, the evaluation and transformation of the two-electron integrals scale cubically with molecular size. If local density fitting approximations are activated, this is reduced to linear scaling. The LCCSD iterations scale quadratically, but linear scaling can be achieved by neglecting some terms involving contractions of single excitations. The accuracy and efficiency of the method is systematically tested using various approximations, and calculations for molecules with up to 90 atoms and 2636 basis functions are presented.
The stability of source localization in a whole-head magnetoencephalography system demonstrated by auditory evoked field measurements
Authors: Chen Kuen-Lin , Yang Hong-Chang , Tsai Sung-Ying , Liu Yu-Wei , Liao Shu-Hsien , Horng Herng-Er , Lee Yong-Ho , Kwon Hyukchan
Published: October 2011

Superconducting quantum interference device (SQUID), which is a very sensitive magnetic sensor, has been widely used to detect the ultra-small magnetic signals in many different territories, especially in the biomagnetic measurement. In this study, a 128-channel SQUID first-order axial gradiometer system for whole-head magnetoencephalography (MEG) measurements was setup to characterize the auditory evoked magnetic fields (AEFs). A 500 Hz monaural pure tone persisting 425 ms with the sound pressure level of 80 dB was randomly applied to the left ear of subject with the inter-stimulus interval of 1.5 ∼ 2.8 s to prevent fatigue of nerves. We demonstrated the characteristic waveforms of AEFs can be accurately recorded and analyzed. Using source localization processes, the origins of AEFs were successfully calculated to be at the auditory cortices which are brain areas known for responsive to sound stimulus. A phantom experiment also proved the good localization accuracy of the established MEG system and measurement procedures. The validated performance of the SQUID system suggests that this technique can also be employed in other brain research.
Interface modes in nanostructured metal-dielectric metamaterials
Authors: Iorsh Ivan , Orlov Alexey , Belov Pavel , Kivshar Yuri
Published: October 2011

We study surface modes at an interface separating two different layered metal-dielectric metamaterials. We demonstrate that, in a sharp contrast to the effective-medium approach predicting a single interface mode with the surface-plasmon dispersion, the transfer-matrix method reveals the existence of three types of localized interface modes, including a backward interface mode. These results confirm that metal-dielectric nanostructured metamaterials can demonstrate strong optical nonlocality due to the excitation of surface plasmon polaritons.
Ab initio investigation of titanium hydroxide isomers and their cations, TiOH0, + and HTiO0, +
Authors: Miliordos Evangelos , Harrison James F. , Hunt Katharine L. C.
Published: October 2011

We studied the electronic and geometrical structure of the [Ti, O, H]0, + species, using large basis sets and both single-reference coupled cluster and multireference configuration interaction methodologies. The electronic structure of HTiO0, + is interpreted qualitatively in terms of a hydrogen atom bonding to TiO0, +, while the structure of TiOH0, + is interpreted in terms of Ti+, 2 + bonding to OH−. Potential energy profiles are reported as functions of the Ti–OH and H–TiO bond lengths, and of the H–Ti–O angle. For a total of 33 stationary points on the potential energy surfaces, we report absolute energies, geometries, and harmonic frequencies. For the neutral species, dipole moments are also given.
Threshold voltage control of Pt-Ti-O gate Si-metal-insulator semiconductor field-effect transistors hydrogen gas sensors by using oxygen invasion into Ti layers
Authors: Usagawa Toshiyuki , Kikuchi Yota
Published: October 2011

Although the threshold voltages (Vth) of the as-processed Pt(15 nm)/Ti(5 nm)-gate Si-MOSFETs under same channel ion dose conditions show a large variation such as 0.846 V among several wafers, the air-annealing and succeeding hydrogen post-annealing procedure for the FETs hydrogen gas sensors leads to excellent uniform Vth distributions and large sensing amplitude ΔVg. The oxygen invasion process through Pt grain boundaries to amorphous Ti layers at 400 °C air-annealing for two hours is not a simple dopant diffusion process but super-heavily oxygen-doped process partly to grow nano-crystalline TiOx. The oxygen-invaded Ti layers change to a kind of new materials; novel mixing layers of nano-crystalline TiOx and super-heavily oxygen-doped amorphous Ti formed on SiO2/Si substrates. The Ti mixing layers change from metals to semiconductors or insulators. As the Ti layers are so thin like 5 nm, the total amount of oxygen invaded into Ti layers will be saturated and stabilized. From the device operation point of view, it is crucial to control the Vth precisely that the Ti novel mixing layers are thin and fully depleted. This is supported by the fact that the Vth change before and after air-annealing procedures can be well explained by the difference of vacuum work function between Pt and Ti.
Impact of carbon incorporation into epitaxial Gd2O3 thin films on silicon: An experimental study on electrical properties
Authors: Laha Apurba , Ai B. , Babu P. R. P. , Fissel A. , Osten H. J.
Published: October 2011

We report on the effect of carbon doping on electrical properties of epitaxial Gd2O3 grown on Si substrates. The incorporation of small amounts of carbon (0.2-0.5 vol. %) into epitaxial Gd2O3 has been found to be very useful in improving the electrical properties especially by reducing the leakage current behavior. The doping has a negligible impact on the structural quality of the oxide layer. We show that the very often found adverse effect of oxygen vacancy induced defects in oxides grown at higher temperature can be eliminated by moderate amount of carbon doping during growth.
All-atom modeling of anisotropic atomic fluctuations in protein crystal structures
Authors: Hafner Jeffrey , Zheng Wenjun
Published: October 2011

The accurate modeling of protein dynamics in crystalline states is essential for the development of computational techniques for simulating protein dynamics under physiological conditions. Following a previous coarse-grained modeling study of atomic fluctuations in protein crystal structures, we have refined our modeling with all-atom representation and force field. We have calculated the anisotropic atomic fluctuations of a protein structure interacting with its crystalline environment either explicitly (by including neighboring proteins into modeling) or implicitly (by adding harmonic restraints to surface atoms involved in crystal contacts). The modeling results are assessed in comparison with the experimental anisotropic displacement parameters (ADP) determined by X-ray crystallography. For a list of 40 high-resolution protein crystal structures, we have found that the optimal modeling of ADPs is achieved when the protein-environment interactions are much weaker than the internal interactions within a protein structure. Therefore, the intrinsic dynamics of a protein structure is only weakly perturbed by crystal packing. We have also found no noticeable improvement in the accuracy of ADP modeling by using all-atom over coarse-grained representation and force field, which justifies the use of coarse-grained modeling to investigate protein dynamics with both efficiency and accuracy.
Polarization and angular effects of femtosecond laser-induced nanostructure-covered large scale waves on metals
Authors: Hwang Taek Yong , Guo Chunlei
Published: October 2011

In this paper, we find that nanostructure-covered large scale waves (NC-LSWs) can be produced on metals using both s- and p-polarized femtosecond laser pulses. We show that the period of NC-LSWs can be controlled by laser fluence, the number of irradiating pulses, and the incident beam angle. By modeling angular dependence of NC-LSW period induced by s-polarized light, we reveal that inhomogeneous energy deposition plays an important role in the formation of NC-LSWs. This allows us to establish a three-step model for NC-LSW formation, the formation of laser-induced surface unevenness, inhomogeneous energy deposition due to the interference of the incident light with the scattered light, and nonuniform energy deposition due to shielding by LSWs.
Kelvin probe study on formation of electric dipole at direct-contact HfO2/Si interfaces
Authors: Miyata Noriyuki , Yasuda Tetsuji , Abe Yasuhiro
Published: October 2011

Although the direct-contact HfO2/Si structure has been demonstrated to have advantages on an equivalent oxide thickness scaling of <1 nm, characteristic electric charges have been reported to be formed at the HfO2/Si interface. A Kelvin probe method was used to examine the electric charges in HfO2/Si structures. We first describe the basic principles behind the Kelvin probe measurements of electric charges in an oxide/Si structure, and then point out what effect the surface adsorbates have on the measured contact-potential-difference voltage (VCPD). A large VCPD difference (>0.5 V) was observed between the direct-contact HfO2/Si and HfO2/SiO2/Si stack surfaces, which suggests the existence of a strong interface dipole. This result is consistent with previous reports using electrical measurements of metal–oxide–semiconductor capacitances. We also found that the dipole completely disappeared after ultrahigh vacuum annealing at 700 °C, and appeared again after exposure to O2 at room temperature. The formation of a dipole by exposure to O2 had a correlation with the formation of Si–O bonds at the HfO2/Si interface. We propose that interface Si–O–Hf bonding naturally produces a strong interface dipole from simple electrostatic potential analysis mainly due to the effect of the large dielectric constant of HfO2.
Waiting time dependence of T2 of protons in water suspensions of iron-oxide nanoparticles: Measurements and simulations
Authors: Chen D.-X. , Via G. , Xu F.-J. , Navau C. , Sanchez A. , Gu H.-C. , Andreu J. S. , Calero C. , Camacho J. , Faraudo J.
Published: October 2011

The transverse relaxation time T2 of protons in water suspensions of iron-oxide particles increases with the waiting time tw after the sample is inserted in the gap of the spectrometer magnet. Such a T2 increase becomes significant if the particles are aggregated into large clusters, for which field-induced formation of cluster-chains will occur and T2 should increase with increasing the length of chains. T2 increases with tw even for small particles, for which no chain formation may be induced, and for large clusters when tw is too small to form long enough chains. The T2 increase is accompanied by a significant echo-time dependence. All this is experimentally and theoretically studied.
Radio frequency emission from high-pressure xenon arcs: A systematic experimental analysis of the underlying near-anode plasma instability
Authors: Hechtfischer Ulrich
Published: October 2011

High-pressure Xe discharge lamps at DC operation can show unwanted strong RF (radio-frequency) emission to beyond 1 GHz, correlated to a sharp periodic lamp-voltage instability in the near-anode plasma with a pulse repetition rate ε of 1–10 MHz. The physical origin of the instability is unclear. Here, its existence and pulse rate have been measured as a function of arc current I = 0.2–1.2 A and anode temperature Ta = 1700–3400 K independently, in experimental lamps with pure-tungsten electrodes and a Xe operating pressure around p = 10 MPa. Surprisingly, the instability is not affected by I or current density j but exists if Ta is lower than a threshold value around 2800–2900 K. The pulse rate ε is simply a rising linear function of the inverse anode temperature 1/Ta, with only a small I-dependent correction. The average anode heat load is slightly lower in the unstable regime and possibly depends on ε. The results allow a consistent re-interpretation of earlier and present experimental observations and should be both a valuable help in practical lamp engineering and a tight constraint for future theories of this effect.
Comparative study of finite temperature demagnetization in Nd2Fe14B and SmCo5 based hard-soft composites
Authors: Belemuk A. M. , Chui S. T.
Published: October 2011

We study with finite temperature Monte Carlo simulation under periodic boundary conditions the demagnetization behavior of exchanged-coupled hard/soft magnets composed of hard cube inclusions (Nd2Fe14B, or SmCo5) in a soft (FeCo) matrix. The easy axis of the hard and soft phases are parallel to the applied field. We study the effect of finite temperature and the soft phase content on the coercivity, the remanence, and the energy product of the composites. We find that because of the difference in magnetization between the two phases, to lower the dipolar energy the magnetization of the two phases is not completely parallel to each other. This results in a much smaller increase of the remnant magnetization with increasing the soft magnet content than anticipated, especially at higher temperatures. This, together with the lower coercivity of Nd2Fe14B, greatly affects the energy product in Nd2Fe14B/FeCo in comparison with SmCo5/FeCo. We underline the essential difference in the induction dependence on the applied field in these compounds.
Equations of state of 2,6-diamino-3,5-dinitropyrazine-1-oxide
Authors: Gump Jared C. , Stoltz Chad A. , Mason Brian P. , Freedman Benjamin G. , Ball Jason R. , Peiris Suhithi M.
Published: October 2011

2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is an energetic ingredient that has an impact sensitivity close to that of TATB, yet a calculated energy content close to HMX. Reported tests of formulated LLM-105 reveal that it is a good candidate for a new insensitive high-performance explosive. As use of LLM-105 increases, thermodynamic parameters and phase stability will need to be determined for accurate modeling. In order to accomplish this goal, isothermal equations of state of LLM-105 at static high-pressure and temperature were investigated using synchrotron angle-dispersive x-ray diffraction and diamond anvil cells. Data at ambient temperature, 100 °C (373 K), and 180 °C (453 K) were used to obtain isothermal equations of state, and data at ambient pressure were used to obtain the volume thermal expansion coefficient. At ambient temperature, 100 °C (373 K), and 180 °C (453 K) no phase change was evident up to the highest measured pressure; and at ambient pressure, LLM-105 was stable up to 240 °C (513 K) and thermally decomposed by 260 °C (533 K).
Influence of crystal orientation and ion bombardment on the nitrogen diffusivity in single-crystalline austenitic stainless steel
Authors: Martinavičius A. , Abrasonis G. , Möller W.
Published: October 2011

The nitrogen diffusivity in single-crystalline AISI 316L austenitic stainless steel (ASS) during ion nitriding has been investigated at different crystal orientations ((001), (110), (111)) under variations of ion flux (0.3–0.7 mA cm−2), ion energy (0.5–1.2 keV), and temperature (370–430 °C). The nitrogen depth profiles obtained from nuclear reaction analysis are in excellent agreement with fits using the model of diffusion under the influence of traps, from which diffusion coefficients were extracted. At fixed ion energy and flux, the diffusivity varies by a factor up to 2.5 at different crystal orientations. At (100) orientation, it increases linearly with increasing ion flux or energy. The findings are discussed on the basis of atomistic mechanisms of interstitial diffusion, potential lattice distortions, local decomposition, and ion-induced lattice vibrational excitations.
Strengthening mechanism of metallic nanoscale multilayer with negative enthalpy of mixing
Authors: Kong Yi , Shen Luming
Published: October 2011

Unlike sharp interfaces usually formed in multilayer thin films with positive enthalpy of mixing, intermixing at interface due to negative enthalpy of mixing can reduce the effectiveness of the interface as dislocation motion barrier and thus weaken the hardness/strength of the multilayer thin film. Through first-principles calculations, however, we find that the large negative enthalpy of mixing may lead to negative interface energy and thus the formation of intermetallic compounds in the interface. The resulting intermetallic compounds may have much higher shear moduli than those of the constituent metals, which can make positive contribution to the hardness enhancement of the nanoscale multilayer thin film.
General approach to polymer chains confined by interacting boundaries. II. Flow through a cylindrical nano-tube
Authors: Freed Karl F. , Wu Chi
Published: October 2011

The Laplace-Green's function methods of Paper I are extended to describe polymers confined in interacting, impenetrable cylindrical geometries, whose treatment is far more challenging than the slit and box geometries considered in Paper I. The general methods are illustrated with calculations (as a function of the polymer-surface interaction) of the free energy of confinement, the radial density profile, and the average of the drag force in the free draining limit, quantities that will be used elsewhere to analyze experiments of Wu and co-workers involving the flow of polymers through nanopores. All these properties are evaluated by numerical inverse Laplace transforms of closed form analytical expressions, a significant savings over the traditional eigenfunction approaches. The example of the confinement free energy for a 3-arm star polymer illustrates the treatment when a closed form expression for the Laplace transform is unavailable.
Accurate ab initio ro-vibronic spectroscopy of the $\tilde X^2 \Pi$X̃2Π CCN radical using explicitly correlated methods
Authors: Grant Hill J. , Mitrushchenkov Alexander , Yousaf Kazim E. , Peterson Kirk A.
Published: October 2011

Explicitly correlated CCSD(T)-F12b calculations have been carried out with systematic sequences of correlation consistent basis sets to determine accurate near-equilibrium potential energy surfaces for the X2Π and a4Σ− electronic states of the CCN radical. After including contributions due to core correlation, scalar relativity, and higher order electron correlation effects, the latter utilizing large-scale multireference configuration interaction calculations, the resulting surfaces were employed in variational calculations of the ro-vibronic spectra. These calculations also included the use of accurate spin-orbit and dipole moment matrix elements. The resulting ro-vibronic transition energies, including the Renner-Teller sub-bands involving the bending mode, agree with the available experimental data to within 3 cm−1 in all cases. Full sets of spectroscopic constants are reported using the usual second-order perturbation theory expressions. Integrated absorption intensities are given for a number of selected vibronic band origins. A computational procedure similar to that used in the determination of the potential energy functions was also utilized to predict the formation enthalpy of CCN, ΔHf(0K) = 161.7 ± 0.5 kcal/mol.
Electronic structures and optical dielectric functions of room temperature phases of SrTiO3 and BaTiO3
Authors: Guo San-Dong , Liu Bang-Gui
Published: October 2011

We investigate the electronic structures and optical dielectric functions of the room temperature phases of SrTiO3 and BaTiO3 by using Tran and Blaha’s modified Becke and Johnson exchange potential. Calculated energy gaps are substantially better than previous first-principles results with respect to experimental values, further calculated optical dielectric functions as functions of photon energy are in good agreement with experimental curves, and calculated zero frequency refractive indexes are also consistent with experiment. This substantial improvement is achieved because the energy levels of the Ti d states are correctly calculated with this new exchange potential. These make a reasonable, reliable understanding of the electronic structures and optical properties of room temperature phases of SrTiO3 andBaTiO3. This approach should be applicable to other semiconducting materials.