bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical properties of well‐isolated single InP/InGaP quantum dots
Authors: Ugur Asli , Kremling Stefan , Hatami Fariba , Höfling Sven , Worschech Lukas , Forchel Alfred , Masselink W. Ted 
Published: April 2012

AbstractEmitting light over a broad spectral range (near infrared to ultra violet) and being photostable, quantum dots as single photon sources have several advantages. Siavalanche photodiodes that are used for photon detection have their highest efficiency in the red spectral window. Ultra low density of InP/InGaP QDs has already been produced with a straightforward technique where the deposition rate of InP is reduced to 0.015 ML/s. With this technique the density of 1 dot per µm2 is realized without the need of lithographic patterning. In the current work we discuss the optical properties of single InP QDs in detail. The low density of QDs allows the investigation of the optical properties of one single dot without using any other apertures. Autocorrelation measurements under cw and pulsed excitation were performed and the values of 0.21 and 0.37 are obtained for g(2)(0), respectively. Electronic structures of the individual QDs are also investigated. The single quantum dots show a distinct perpendicular linearly polarized fine structure splitting up to 320 µeV. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ study of hydrogen diffusion in a‐Si:H based junctions exposed to hydrogen plasma
Authors: Larbi Fadila , Fellah Samira , Hadjadj Aomar , Roca i Cabarrocas Pere , Dine Sib Jamal 
Published: April 2012

AbstractJust after their deposition by plasma enhanced chemical vapor deposition (PECVD) process, we have exposed Cr/I/N, Cr/I/P, Cr/N/I and Cr/P/I a‐Si:H based junctions to H2 plasma and followed in situ, by ellipsometry, the modifications induced by hydrogen diffusion. In the case of Cr/N/I and Cr/P/I junctions, no significant effects of the junction on the hydrogen diffusion were observed since the time‐evolution of the thickness of the H‐modified layer is similar to that of a single intrinsic layer. However, Cr/I/N, Cr/I/P structures present an attenuated thickness of the H‐modified layer in the first few minutes of hydrogen plasma exposure. This effect should be attributed to the charges in the field regions of I/N or I/P junctions which increase the hydrogen trap concentration and restrain the hydrogen diffusion. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of capacitance spectroscopy of (p) a‐Si:H/(n) c‐Si interfaces
Authors: Maslova Olga , Brézard‐Oudot Aurore , Favre Wilfried , Alvarez José , Gudovskikh Alexander , Terukov Eugene , Kleider Jean‐Paul 
Published: April 2012

AbstractHydrogenated amorphous silicon/crystalline silicon (a‐Si:H/c‐Si) heterojunctions are promising candidates for high efficiency solar cells. The performance of such cells is strongly dependent on the interfacial properties namely defect states and band discontinuities. Capacitance spectroscopy of (p) a‐Si:H/ (n) c‐Si heterojunctions has been used to study fundamental properties of such structures. Numerical calculations of a‐Si:H/c‐Si heterojunction capacitance (C) vs temperature (T) and frequency (f) show a capacitance step. We have studied the dependence of the step activation energy (Ea) on various heterojunction parameters such as the position of the Fermi level in a‐Si:H, capture cross sections of gap states in a‐Si:H, values of band offsets, carrier mobility. It is shown that Ea generally corresponds to the energy difference between the Fermi level and the bottom of the valence band in the bulk a‐Si:H and is related to the transport in a‐Si:H and to the response of gap states at the Fermi level through capture and emission of holes. However, if very large values of hole mobility in a‐Si:H are introduced in the modeling, larger values of Ea, close to that of the valence band offset, are obtained, revealing a contribution from the modulation of free holes in the strong inversion layer at the c‐Si surface. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prediction of conformational population of large cycloalkanes using ab initio correlated methods: Cycloundecane, cyclododecane, and cyclotridecane
Authors: Dos Santos Hélio F. , Franco Mauro L. , Venâncio Mateus F. , Ferreira Dalva E. C. , Anconi Cleber P. A. , Rocha Willian R. , De Almeida Wagner B. 
Published: April 2012

AbstractWe report MP4(SDTQ) and CCSD(T) ab initio temperature‐dependent conformational populations for a series of cycloalkanes with increasing ring size, cycloundecane (11‐C), cyclododecane (12‐C), and cyclotridecane (13‐C), using extended basis sets. Our aim is to analyze the commonly used quantum chemical procedure for evaluating the thermal energy contribution to Gibbs free energy particularly the adequacy of standard harmonic oscillator vibrational partition function for large molecular systems. Experimental population data for cycloundecane, obtained from low temperature (90.1 K) 13C NMR, and cyclododecane, from gas phase electron diffraction experiment at 393.15 K, are available, and we found a good agreement with MP4(SDTQ) and CCSD(T) ab initio calculated conformational population. Our results indicate that the procedure of considering all 3N‐6 vibrational modes as harmonic oscillators seems adequate for the prediction of the preferred conformer of cycloundecane, cyclododecane, and cyclotridecane, in the absence of a more appropriate approach to treat the low frequency modes that is applicable for large molecules. Therefore, it can be expected to work satisfactorily in room temperature conformational analysis studies on large molecules containing a great number of vibrational frequencies below 625 cm−1, such as in supramolecular chemistry, biological, and material science applications. © 2012 Wiley Periodicals, Inc.
PREDICTING ECOLOGICAL FLOW REGIME AT UNGAGED SITES: A COMPARISON OF METHODS
Authors: Murphy J. C. , Knight R. R. , Wolfe W. J. , S. Gain W. 
Published: April 2012

ABSTRACTNineteen ecologically relevant streamflow characteristics were estimated using published rainfall–runoff and regional regression models for six sites with observed daily streamflow records in Kentucky. The regional regression model produced median estimates closer to the observed median for all but two characteristics. The variability of predictions from both models was generally less than the observed variability. The variability of the predictions from the rainfall–runoff model was greater than that from the regional regression model for all but three characteristics. Eight characteristics predicted by the rainfall–runoff model display positive or negative bias across all six sites; biases are not as pronounced for the regional regression model. Results suggest that a rainfall–runoff model calibrated on a single characteristic is less likely to perform well as a predictor of a range of other characteristics (flow regime) when compared with a regional regression model calibrated individually on multiple characteristics used to represent the flow regime. Poor model performance may misrepresent hydrologic conditions, potentially distorting the perceived risk of ecological degradation. Without prior selection of streamflow characteristics, targeted calibration, and error quantification, the widespread application of general hydrologic models to ecological flow studies is problematic. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.
The Bernese Program against Victimization in Kindergarten and Elementary School
Authors: Alsaker Françoise D. , Valkanover Stefan 
Published: April 2012

AbstractThe Bernese Program against Victimization in Kindergarten and Elementary School was designed to be adaptable to the very different situations and needs encountered by teachers in kindergarten and elementary school. The basic principle of the program is to enhance teachers' ability to address bullying. The program consists of six modules, each corresponding to a specific topic. Teachers are urged to implement the tasks discussed during the meetings in their own classes during the time between the meetings. The program has been evaluated using a prevention‐control pre‐ and posttest design. The informants were teachers as well as children. There was a significant interaction between time (pre‐ and posttest) and group (prevention and control) as to victimization. Changes in teachers' attitudes toward bullying and their ability to cope with such problems were also significant and in the expected direction.
The Zero program
Authors: Roland Erling , Midthassel Unni Vere 
Published: April 2012

AbstractZero is a schoolwide antibullying program developed by the Centre for Behavioural Research at the University of Stavanger, Norway. It is based on three main principles: a zero vision of bullying, collective commitment among all employees at the school using the program, and continuing work. Based on these principles, the program aims to reduce student bullying by increasing the school's ability to uncover and stop bullying, and eventually to prevent it. The Zero program was launched in 2003, but the work that led to it goes back to the first national steps against bullying in 1983. The program extends over sixteen months as teachers develop their awareness of bullying and their competence in addressing it. Students and parents are involved in the program as well. The role of the school leadership is very important. More than 360 Norwegian schools have carried out the program.
Placing Darwin into the heart of the Natural History Museum
Authors: Bloomfield Robert M. 
Published: April 2012

Abstract
In 2009, the Natural History Museum, London celebrated the bicentenary of Charles Darwin and the sesquicentennial of his seminal work The Origin of Species by Means of Natural Section by commissioning a new contemporary artwork as a permanent insertion into the famous grade one listed Waterhouse architecture in South Kensington. This article explores the motivation and delivery of this extraordinary work and its deeper message for today and tomorrow.
Isotropization at small scales of rotating helically driven turbulence
Authors: Mininni P. D. , Rosenberg D. , Pouquet A. 
Published: April 2012

AbstractWe present numerical evidence of how three-dimensionalization occurs at small scale in rotating turbulence with Beltrami ($\mathit{ABC}$) forcing, creating helical flow. The Zeman scale ${\ell }_{\Omega } $ at which the inertial and eddy turn-over times are equal is more than one order of magnitude larger than the dissipation scale, with the relevant domains (large-scale inverse cascade of energy, dual regime in the direct cascade of energy $E$ and helicity $H$, and dissipation) each moderately resolved. These results stem from the analysis of a large direct numerical simulation on a grid of $307{2}^{3} $ points, with Rossby and Reynolds numbers, respectively, equal to $0. 07$ and $2. 7\ensuremath{\times} 1{0}^{4} $. At scales smaller than the forcing, a helical wave-modulated inertial law for the energy and helicity spectra is followed beyond ${\ell }_{\Omega } $ by Kolmogorov spectra for $E$ and $H$. Looking at the two-dimensional slow manifold, we also show that the helicity spectrum breaks down at ${\ell }_{\Omega } $, a clear sign of recovery of three-dimensionality in the small scales.
Beneficial effects of the active principle component of Korean cabbage kimchi via increasing nitric oxide production and suppressing inflammation in the aorta of apoE knockout mice
Authors: Noh Jeong Sook , Choi Yung Hyun , Song Yeong Ok 
Published: April 2012

The present study investigated the effects of 3′-(4′-hydroxyl-3′,5′-dimethoxyphenyl)propionic acid (HDMPPA), the active principle compound of kimchi, on vascular damage in the experimental atherosclerotic animal. HDMPPA was administrated by an intraperitoneal injection of 10 mg/kg per d for 8 weeks to apoE knockout (KO) mice with an atherogenic diet containing 1 % cholesterol, and its effects were compared with vehicle-treated control mice. HDMPPA increased NO content in the aorta, accompanied by a decrease in reactive oxygen species (ROS) concentration. Furthermore, in the HDMPPA-treated group, aortic endothelial NO synthase (eNOS) expression was up-regulated compared with the control group. These results suggested that HDMPPA could maintain NO bioavailability through an increasing eNOS expression and preventing NO degradation by ROS. Furthermore, HDMPPA treatment in apoE KO mice inhibited eNOS uncoupling through an increase in vascular tetrahydrobiopterin content and a decrease in serum asymmetric dimethylarginine levels. Moreover, HDMPPA ameliorates inflammatory-related protein expression in the aorta of apoE KO mice. Therefore, the present study suggests that HDMPPA, the active compound of kimchi, a Korean functional food, may exert its vascular protective effect through the preservation of NO bioavailability and suppression of the inflammatory response.
A cohort study on diet and the risk of Parkinson's disease: the role of food groups and diet quality
Authors: Sääksjärvi K. , Knekt P. , Lundqvist A. , Männistö S. , Heliövaara M. , Rissanen H. , Järvinen R. 
Published: April 2012

Previous studies on individual foods and nutrients and Parkinson's disease (PD) risk have been inconsistent. Furthermore, only one study has examined the association between the quality of diet and PD. We investigated the prediction of food groups and diet quality on PD in the Finnish Mobile Clinic Survey (1966–72). The population comprised 4524 individuals, aged 40–79 years and free from PD at baseline. Data collection included health examinations, a questionnaire and a 1-year dietary history interview. A modified Alternate Healthy Eating Index was formed to assess diet quality. Statistical analyses were based on Cox's model. During a 41-year follow-up, eighty-five incident cases of PD occurred. No statistically significant associations were found between PD incidence and most of the food groups examined. A few exceptions were fruits and berries in men and milk in women, which showed positive associations. An inverse association between the intake of meat products and PD was found in women. The diet quality index did not predict PD, the adjusted relative risk between the highest and lowest quartiles being 1·83 (95 % CI 0·65, 5·18) in men and 0·97 (95 % CI 0·38, 2·48) in women. The present study suggests that since most of the single food groups or the quality of diet did not predict PD occurrence, the role of diet is apparently rather modest.
Comparison of the Block Kid's Food Frequency Questionnaire with a 24 h dietary recall methodology among Hmong-American children, 9–18 years of age
Authors: Mulasi-Pokhriyal Urvashi , Smith Chery 
Published: April 2012

Hmong are one of the immigrant Asian subgroups with increasing rates of obesity, type 2 diabetes and CVD. Despite their population growth in the USA and declining health status, no research has investigated the appropriateness of dietary assessment measures, including FFQ and 24 h dietary recalls among Hmong. The present study compared the nutrient information obtained through a 24 h dietary recall method with that collected using the Block Kid's Food Frequency Questionnaire (Block FFQ) among Hmong-American children (n335) of 9–18 years of age. For this purpose, two 24 h dietary recalls were collected during non-consecutive days and averaged for comparison. The Block FFQ was administered on the day of the second 24 h recall and the two methodologies were also compared usingttests. Among all children, Block FFQ nutrient estimates for vitamin A, vitamin C and food group servings for vegetables and fruits were significantly higher than those assessed through the 24 h dietary recalls (P< 0·001). Nutrient estimates for protein and food group servings for grains and meat and beans were significantly higher among all participants when assessed through the 24 h dietary recalls than through the Block FFQ (P< 0·05). The results suggest that the Block FFQ does not appear to be a good measure of protein, grain, and meat and bean intake among Hmong children of 9–18 years of age, and the 24 h dietary recall offers a better account of the Hmong diet and is inclusive of ethnic food options otherwise missed in the Block FFQ. We recommend the modification of the current Block FFQ to appropriately reflect cultural food/beverage items of the population in interest.
The abundance ofIxodes ricinusticks depends on tree species composition and shrub cover
Authors: TACK W. , MADDER M. , BAETEN L. , DE FRENNE P. , VERHEYEN K. 
Published: April 2012

SUMMARYThe mainstream forestry policy in many European countries is to convert coniferous plantations into (semi-natural) deciduous woodlands. However, woodlands are the main habitat forIxodes ricinusticks. Therefore, assessing to what extent tick abundance and infection withBorreliaspirochetes are affected by forest composition and structure is a prerequisite for effective prevention of Lyme borreliosis. We selected a total of 25 pine and oak stands, both with and without an abundant shrub layer, in northern Belgium and estimated tick abundance between April and October 2008–2010. Additionally, the presence of deer beds was used as an indicator of relative deer habitat use.Borreliainfections in questing nymphs were determined by polymerase chain reactions. The abundance of larvae, nymphs, and adults was higher in oak stands compared to pine stands and increased with increasing shrub cover, most likely due to differences in habitat use by the ticks' main hosts. Whereas tick abundance was markedly higher in structure-rich oak stands compared to homogeneous pine stands, theBorreliainfection rates in nymphs did not differ significantly. Our results indicate that conversion towards structure-rich deciduous forests might create more suitable tick habitats, but we were unable to detect an effect on the infection rate.
CAN WE RELIABLY BENCHMARK HEALTH TECHNOLOGY ASSESSMENT ORGANIZATIONS?
Authors: Drummond Michael , Neumann Peter , Jönsson Bengt , Luce Bryan , Schwartz J. Sanford , Siebert Uwe , Sullivan Sean D. 
Published: April 2012

Objectives: In recent years, there has been growth in the use of health technology assessment (HTA) for making decisions about the reimbursement, coverage, or guidance on the use of health technologies. Given this greater emphasis on the use of HTA, it is important to develop standards of good practice and to benchmark the various HTA organizations against these standards.Methods: This study discusses the conceptual and methodological challenges associated with benchmarking HTA organizations and proposes a series of audit questions based on a previously published set of principles of good practice.Results and Conclusions: It is concluded that a benchmarking exercise would be feasible and useful, although the question of who should do the benchmarking requires further discussion. Key issues for further research are the alternative methods for weighting the various principles and for generating an overall score, or summary statement of adherence to the principles. Any weighting system, if developed, would need to be explored in different jurisdictions to assess the extent to which the relative importance of the principles is perceived to vary. Finally, the development and precise wording of the audit questions requires further study, with a view to making the questions as unambiguous as possible, and the reproducibility of the assessments as high as possible.
The hydrography of the Rockall Channel—an overview
Authors: Ellett D. J. , Edwards A. , Bowers R. 
Published: April 2012

SynopsisThe water masses, major circulation features and long-term variability of Rockall Channel waters are reviewed in relation to work in recent years. Data collected with modern instruments disclose more detail in the water mass structure than found previously, and the range of water masses present in the Channel is examined.The use of recording current meter moorings has amplified our knowledge of the processes occurring within the Rockall Channel circulation, although net flows remain difficult to evaluate. Eddy motions suggested by current meter records and geostrophic data are confirmed by the trajectories of satellitetracked drogues.Changes in the temperature and salinity of the upper waters of the Rockall Channel from the early years of this century to the present are clearly detectable, and a brief account is given of these.
Estimating the true incidence of campylobacteriosis and salmonellosis in the European Union, 2009
Authors: HAVELAAR A. H. , IVARSSON S. , LÖFDAHL M. , NAUTA M. J. 
Published: April 2012

SUMMARYWe estimated the true incidence of campylobacteriosis and salmonellosis in the European Union (EU) in 2009. The estimate was based on disease risks of returning Swedish travellers, averaged over the years 2005–2009, and anchored to a Dutch population-based study on incidence and aetiology of gastroenteritis. For the 27 EU member states the incidence of campylobacteriosis was about 9·2 (95% CI 2·8–23) million cases, while the incidence of salmonellosis was 6·2 (95% CI 1·0–19) million cases. Only 1/47 (95% CI 14–117) cases of campylobacteriosis and one 1/58 (95% CI 9–172) cases of salmonellosis were reported in the EU. The incidence rate of campylobacteriosis in EU member states varied between 30 and 13 500/100 000 population and was significantly correlated with the prevalence of Campylobacter spp. in broiler chickens. The incidence rate of salmonellosis in EU member states varied between 16 and 11 800/100 000 population and was significantly correlated with the prevalence of Salmonella Enteritidis in laying hens.
Detection of negative ions in the deep ionosphere of Titan during the Cassini T70 flyby
Authors: Ågren K. , Edberg N. J. T. , Wahlund J.‐E. 
Published: April 2012

We present radio and plasma wave science (RPWS) Langmuir probe (LP) observations that give evidence for a population of heavy, negative ions at altitudes below 900 km in Titan's ionosphere during the Cassini T70 flyby. The negative ion density in this region is comparable to, or higher than, the electron density of 760 cm−3. Both positive and negative ions are moving with a velocity of at least a few hundred m s−1 relative to Titan. We show two limiting cases where we have analysed RPWS/LP ion measurements. The data can be interpreted as either that a population of negative ions with density comparable to the electron density is present, moving at a very high (>2 km s−1) velocity, or that the ion population is moving at a few hundred m s−1, but with a density an order of magnitude larger than the electron density in the same region.
Geometrical and electrical characteristics of the initial stage in Florida triggered lightning
Authors: Hill J. D. , Pilkey J. , Uman M. A. , Jordan D. M. , Rison W. , Krehbiel P. R. 
Published: April 2012

We characterize the geometrical and electrical characteristics of the initial stages of nine Florida triggered lightning discharges using a Lightning Mapping Array (LMA) and measured channel‐base currents. We determine initial channel and subsequent branch lengths, average initial channel and branch propagation speeds, and channel‐base current at the time of each branch initiation. The channel‐base current is found to not change significantly when branching occurs, an unexpected result. The initial stage of Florida triggered lightning typically transitions from vertical to horizontal propagation at altitudes of 3–6 km, near the typical freezing level of 4 km and several kilometers below the expected center of the negative cloud‐charge region at 7–8 km. The data presented potentially provide information on thunderstorm electrical and hydrometeor structure and discharge propagation physics. LMA source locations were obtained from VHF sources of positive impulsive currents as small as 10 A, in contrast to expectations found in the literature.