bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation of symmetric and asymmetric metal–semiconductor hybrid nanoparticles
Authors: Mokari T. , Costi R. , Sztrum C. G. , Rabani E. , Banin U. 
Published: October 2006

AbstractMulti‐component nano‐systems are created by combining two or more different materials yielding new chemical and physical properties. Here we report the selective anisotropic growth creating hybrid nanparticles of two different material systems, a metal onto a semiconductor. We developed a simple method for the selective growth of gold tips onto the apexes of colloidal semiconductor nanorods and tetrapods. This combination provides new functionalities to the nanostructures, the most important of which is the formation of natural anchor points that can serve as a recognition element for directed self assembly and for wiring them onto electrical circuitry. At higher gold concentrations we observe a transition from two to one‐sided gold growth. This behavior is attributed to a ripening process as was also studied using a theoretical model. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High fidelity measurement of singlet–triplet state in a quantum dot
Authors: Meunier T. , Tielrooij K.‐J. , Vink I. T. , Koppens F. H. L. , Tranitz H. P. , Wegscheider W. , Kouwenhoven L. P. , Vandersypen L. M. K. 
Published: October 2006

AbstractWe demonstrate experimentally a read‐out method that distinguishes between two‐electron spin states in a quantum dot. This scheme combines the advantages of the two existing mechanisms for spin‐to‐charge conversion with single‐shot charge detection: a large difference in energy between the two states and a large difference in tunnel rate between the states and a reservoir. As a result, a spin measurement fidelity of 97% was achieved, which is much higher than previously reported fidelities. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin properties of charged single Mn‐doped quantum dots
Authors: Léger Y. , Besombes L. , Maingault L. , Fernández‐Rossier J. , Ferrand D. , Mariette H. 
Published: October 2006

AbstractThe optical properties of individual quantum dots doped with a single Mn atom and charged with a single carrier (electron or hole) are analyzed. The emission of the neutral, positively charged and negatively charged excitons coupled with a single magnetic atom are observed in the same quantum dot. The spectrum of the charged excitons in interaction with the Mn atom shows a rich pattern attributed to a strong anisotropy of the hole–Mn exchange interaction slightly perturbed by a small valence band mixing. For the positively charged exciton, the emission pattern shows that the different spin states of the hole–Mn complex remain split in the final state after the exciton recombination. This opens the possibility of storing information on a single carrier spin on a long time scale in the absence of external magnetic field. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin blockade in lateral quantum dots – Negative differential conductance and spin spectroscopy
Authors: Rogge M. C. , Kupidura D. , Reinwald M. , Wegscheider W. , Haug R. J. 
Published: October 2006

AbstractWe report on spin blockade observed in several different lateral quantum dot systems. We observe the typical features of alternating position and amplitude of Coulomb peaks as a function of a magnetic field perpendicular to the sample surface. In a nonlinear regime strong negative differential conductance is observed with a striking regularity. This is not a universal behaviour. Instead we propose a complex interplay of spin blockade, electron interaction and relaxation. At strong tunnel coupling to the leads we use spin blockade as a spectroscopy tool to reveal the spin configuration in a Kondo regime with a pronounced chessboard pattern. By comparing measurements of different samples we find that Kondo effect and spin blockade can be combined in two different ways depending on the spin configuration of the dot. Thus the combination of both effects can be used to detect spin polarized filling of dot orbitals instead of regular filling. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hole and electron wave functions in self‐assembled InAs quantum dots: a comparison
Authors: Reuter D. , Kailuweit P. , Roescu R. , Wieck A. D. , Wibbelhoff O. S. , Lorke A. , Zeitler U. , Maan J. C. 
Published: October 2006

AbstractWe have investigated the conduction and the valence band states of self‐assembled InAs quantum dots embedded in n‐ and p‐type Schottky diodes, respectively, by magneto‐capacitance voltage spectroscopy. The dispersion behaviour of the individual charging peaks in a perpendicular magnetic field shows qualitative differences between the two carrier types. By applying an in‐plane magnetic field, the momentum space wave function corresponding to the individual charging peaks could be mapped. For electrons, the s‐like wave function for the ground state is slightly asymmetric with the low energy direction along [0$ \bar 1 $1] in real space. Also the s‐like wave function for the hole ground state is asymmetric but here the low energy direction is along [011], i.e. orthogonal to that for electrons. This hints to an asymmetry in the confinement potential that is caused by piezoelectric effects. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin relaxation of positive trions in InAs/GaAs quantum dots: the role of hyperfine interaction
Authors: Braun Pierre‐François , Eble Benoît , Lombez Laurent , Urbaszek Bernhard , Marie Xavier , Amand Thierry , Renucci Pierre , Krebs Olivier , Lemaître Aristide , Voisin Paul , Kalevich Vladimir K. , Kavokin Kyrill V. 
Published: October 2006

AbstractWe report on positive trion (X+) spin relaxation in self‐assembled InAs/GaAs quantum dots. The hyperfine interaction between the electron and nuclear spins acts as a randomly oriented magnetic field for the electron spin, giving rise to ensemble dephasing and thus to partial relaxation in less than 1 ns. Time‐resolved photoluminescence polarization measurements carried out on an ensemble of InAs/GaAs quantum dots, charged with excess holes by proximity p‐doping, reveal this peculiar dynamics. The fast polarization decrease can be efficiently suppressed by screening the hyperfine interaction with a longitudinal magnetic field of 100 mT. The quenching of this hyperfine‐induced relaxation is also evidenced for a single charge‐tunable quantum dot in the regime of X+ photoluminescence and excited with modulated polarization to prevent dynamic nuclear polarization. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Controlled Ge quantum dots positioning with nano‐patterned Si(001) substrates
Authors: Bavard A. , Eymery J. , Pascale A. , Fournel F. 
Published: October 2006

AbstractA square nanometric patterned substrate (period 20 nm) is obtained by direct twist bonding of two twin Si(001) surfaces, thinning and preferential chemical etching. Molecular beam epitaxy of Ge is carried out on a sample having heterogeneous trench depths to analyse islands positioning as a function of the surface morphology. Scanning electron microscopy observations show that small single dots per mesa or large dots covering several mesas can be observed. It highlights the influence of the mesa aspect ratio on the control of Ge islands self‐organization, and suggests the occurrence of an effective activation barrier depending on the surface profile. The position‐dependent energy stored in a dot for a given surface profile is estimated from a very simple model based on the balance between capillarity and elastic relaxation terms. By choosing a cycloid‐like profile, experimental observations can be explained without fitting parameters. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Soil organic carbon budget and fertility variation of black soils in Northeast China
Authors: Yu Guirui , Fang Huajun , Gao Lupeng , Zhang Wenjuan 
Published: October 2006

AbstractBlack soils in Northeast China are characteristic of high soil organic carbon (SOC) density and were strongly influenced by human activities. Therefore, any change in SOC pool of these soils would not only impact the regional and global carbon cycle, but also affect the release and immobilization of nutrients. In this study, we reviewed the research progress on SOC storage, budget, variation, and fertility under different scenarios. The results showed that the organic carbon storage of black soils was 646.2 TgC and the most potential sequestration was 2887.8 g m−2. According to the SOC budget, the net carbon emission of black soils was 1.3 TgC year−1 under present soil management system. The simulation of CENTURY model showed that future climate change and elevated CO2 concentration, especially the increase of precipitation, would increase SOC content. Furthermore, fertilization and cropping sequence obviously influenced SOC content, composition, and allocation among different soil particles. Long‐term input of organic materials such as manure and straw renewed original SOC, improved soil structure and increased SOC accumulation. Besides, soil erosion preferred to transport soil particles with low density and fine size, decreased recalcitrant SOC fractions at erosion sites and increased activities of soil microorganism at deposition sites. After natural grasslands were converted into croplands, obvious variation of soil chemical nutrients, physical structure, and microbial activities had taken place in surface and subsurface soils, and represented a degrading trend to a certain degree. Our studies suggested that adopting optimal management such as conservation tillage in black soil region is an important approach to sequester atmospheric CO2 and to slow greenhouse effects.
International Biodiversity Observation Year in Western‐Pacific and Asian regions (DIWPA‐IBOY): a case report on species rarity and spatio‐temporal variability of species composition in Lepidoptera and Coleoptera communities from a temperate forest of northern Japan
Authors: Hirao Toshihide , Murakami Masashi , Kogi Hiroyuki , Kashizaki Akira , Hirai Yoshiyuki , Tanabe Shin‐ich , Inari Naoki , Yorozuya Hiroshi , Toda Masanori J. 
Published: October 2006

AbstractAn international project, DIWPA‐IBOY, took place for simultaneously observing biodiversity throughout the Western‐Pacific and Asian regions in 2001–2003, as one of the core projects for International Biodiversity Observation Year, a crosscutting network activity of DIVERSITAS (an international programme of biodiversity science). DIWPA‐IBOY provides extensive data on species diversity obtained by the standardized method. Under this project, 51,742 individuals of Lepidoptera and 11,633 of Coleoptera were collected by light traps from the Tomakomai Experimental Forest of Hokkaido University, one of the core DIWPA‐IBOY sites, in the cool‐temperate region of northern Japan. Based on these data, this study examined the relative abundance distribution (RAD) to evaluate the amount of rare species in the Lepidoptera and Coleoptera communities. The beta diversities between sampling seasons, forest strata, and trap sites were also assessed to evaluate the spatio‐temporal variability of species composition in these communities. In the analysis of the RAD, the best‐fit model was selected from the log‐Normal, Zipf–Mandelbrot, and Zipf models differing in the tail length of the RAD, i.e., the proportion of rare species. To explore the beta diversity between samples, the abundance‐based Jaccard index with an unseen species estimator was calculated, and then a hierarchical clustering analysis was conducted. As a result of RAD analysis, the Coleoptera community was regarded as containing a larger proportion of rare species than the Lepidoptera community. The seasonal compartmentalization of the community, deduced from the beta‐diversity analysis, was finer in Lepidoptera (seven assemblages recognized) than in Coleoptera (three assemblages). The spatial (vertical and horizontal) compartmentalization was negligible in both communities. The coincidence of the larger proportion of rare species and the lower beta diversity between seasons in the Coleoptera community was explained by the longer life spans of beetles compared to moths, based on the assumption that the length of life span acts as a temporal agent for mass effect on the analogy of the migration rate as a spatial agent for mass effect.
Assessment of higher insect taxa as bioindicators for different logging‐disturbance regimes in lowland tropical rain forest in Sabah, Malaysia
Authors: Akutsu Kosuke , Khen Chey Vun , Toda Masanori J. 
Published: October 2006

AbstractOne of the serious environmental problems since the 1980s has been the conflict between the high rate of deforestation and maintenance of healthy ecosystem services and biological values in tropical forests. There is an urgent demand for setting up an appropriate environmental assessment to keep healthy ecosystem functions and biodiversity along with sustainable forest use based on ecology. In this study, we tried to assess logging‐disturbance effects on the abundances of several flying insect groups (higher‐taxon approach) in lowland tropical rain forest (Deramakot Forest Reserve, Sabah, Malaysia), while considering seasonal changes and vertical forest stratification. The season was the most important factor affecting the abundances of all the insect groups. Effects of logging disturbance were prominent in the understorey but obscure in the canopy. Changes in physical conditions caused by logging—possibly an increased evaporation due to solar radiation—may have decreased the abundance of desiccation‐sensitive insects, especially in the understorey. There are also two probable reasons for the difference between events in the understorey and those in the canopy: (1) noise effects of various physical, environmental factors may have obscured insect responses to logging disturbance in the canopy; (2) higher spatio‐temporal variation in quality and quantity of living food resources—such as leaves, flowers and fruits—provided in the canopy may have affected the abundance of their consumer insects independently of logging disturbance. Thus, this study suggests that the abundance of some insect groups at higher‐taxon level, especially in the understorey, can be used as bioindicators for assessing effects of logging disturbance on the forest ecosystem.
The correspondence between persistent self-reported post-traumatic problems and general practitioners' reports after a major disaster
Authors: DROGENDIJK ANNELIEKE N. , DIRKZWAGER ANJA J. E. , GRIEVINK LINDA , VAN DER VELDEN PETER G. , MARCELISSEN FRANS G. H. , KLEBER ROLF J. 
Published: October 2006

Background. Little is known about the correspondence between persistent self-reported disaster-related psychological problems and these problems reported by general practitioners (GPs). The aim of this study is to analyse this correspondence and to identify the factors associated with GPs' detection of persistent psychological problems.Method. This study was conducted in a sample of 879 adult disaster-affected victims, taken from two longitudinal sources: the Enschede Firework Disaster Study and the GP-Monitor Study. Participants filled out a questionnaire 2–3 weeks and 18 months post-disaster and these data were combined with data from a GP-monitor collected up to 18 months post-disaster. The correspondence between persistent self-reported and GP-reported psychological problems was analysed with cross-tabulations. Logistic regression analyses were performed to identify variables which predicted GPs' detection of psychological problems.Results. The correspondence rate among victims who visited their GP 18 months post-disaster was 60·4% for persistent intrusions and avoidance reactions, 72·6% for persistent general psychological distress and less than 20% for persistent depression and anxiety symptoms or sleep disturbances. Characteristics that predict GPs' identification of post-traumatic reactions or psychological distress were the level of self-reported post-traumatic symptoms/mental health, the number of contacts the victims had with their GP and the level of the victims' disaster-related experiences.Conclusions. In general, there is a considerable correspondence between GP-reported and persistent self-reported incidences of post-traumatic stress and general psychological distress in disaster-affected victims. However, the correspondence declines in the case of more specific psychological symptoms.
Increased sensitivity to stress associated with noradrenergic hyperactivity, involving dopaminergic hyperactivity in spontaneous recurrences in methamphetamine psychosis
Authors: Yui Kunio , Goto Kimihiko , Ikemoto Shigenori , Jima Koichi Nisi , Kamada Yoshinori , Ishiguro Takeo 
Published: October 2006

AbstractThe study examined the significance of increased sensitivity to stress associated with noradrenergic hyperactivity and dopaminergic changes in spontaneous recurrences of methamphetamine (MAP) psychosis (flashbacks). Plasma monoamine metabolite levels were assayed in the subjects: 19 flashbackers, 18 non‐flashbackers with a history of MAP psychosis and 37 controls. Monoaminergic values underwent a square‐root transformation. All flashbackers had been exposed to stressful events plus MAP‐induced fear‐related psychotic symptoms (n = 11) or fear‐related symptoms alone (n = 8). Factors triggering flashbacks met the DSM‐III‐R criteria for mild psychosocial stressors. During flashbacks norepinephrine levels increased markedly and 3‐methoxytyramine, which is indicative of dopaminergic activity, increased to a lesser extent. Among the flashbackers, 11 with a history of stressful events plus fear‐related symptoms displayed further a small increase in 3‐methoxytyramine levels. Thus, stressful events plus fear‐related symptoms, together with MAP use, may induce noradrenergic hyperactivity and some degree of dopaminergic hyperactivity in response to mild stressors. Increased sensitivity to stress associated with a predominance of noradrenergic over dopaminergic hyperactivity may be a precipitating factor in flashbacks.
Alcohol genetics: will the promise be fulfilled?
Authors: Cook Chris 
Published: October 2006

AbstractGenetic research into alcohol‐related problems has a long history, but only with the recent advent of molecular biological techniques does it seem poised to fulfill its promise. While such research might be thought to reinforce views of the inevitability and immutability of drinking problems, there have been bold promises of important developments in our understanding of the aetiology of alcohol misuse, as well as promises of innovations in prevention and treatment. A brief consideration of recent research, and of the possibilities that are now before us, reveals that the promise of increased understanding of the aetiology of alcohol misuse is already being fulfilled. Promises of new preventive and therapeutic interventions, if they also are to be fulfilled, require that a number of practical and ethical issues be addressed. Clinicians, researchers and others in the addictions field need to begin to address the ethical issues that are raised.
Book and Media Reviews
Authors: Ball David 
Published: October 2006

Books reviewed in this article:Book reviews in this column will primarily be of titles focusing completely, or in part, on biological aspects of addiction. However, significant titles of general relevance to the addictions field will also be included, even if they are not “biological”, as will titles of general methodological and clinical relevance, even if they are not on “addictions”. Similar considerations will apply to other media (software, audio tapes and CDs, videos, etc). However, specific “addictions” software applications seem to be relatively uncommon and, as these items are rarely reviewed elsewhere, we will endeavour to include reviews of some of the older programmes that are still useful, as well as new titles that appear. I would appreciate suggesti ons of any items suitable for reviews, but especially software and other media of specifi c relevance to the addictions. Please contact: Dr David Ball, National Addiction Centre, 4 Windsor Walk, London SE5 8AF, UK. Dual Diagnosis and Treatment: substance abuse and co‐morbid medical and psychiatric disorders HENRY R. KRANZLER & BRUCE J. ROUNSAVILLE (Eds) Improving the Care of People in Substance Misuse Ser vices: clinical audit project examples KIRSTY MACLEAN STEEL & CLAIRE PALMER Software

European Legal Texts on Drugs (CD‐Rom)
Neuroendocrine pathways of addictive behaviour
Authors: Kiefer F , Wiedemann K 
Published: October 2006

AbstractAlcohol intake is known to modulate plasma concentrations of neuroendocrine peptides. However, recent results suggest that the endocrine system may not only respond passively to alcohol intake but that, vice versa, it also actively modulates alcohol intake behaviour. The most coherent body of data concerns the hypothalamo ‐ pituitary ‐ adrenocortical (HPA) axis, with low corticotrophin‐releasing hormone (CRH) being associated with more intense craving and increased probability of relapse after acute detoxification. Leptin, β‐endorphin and atrial natriuretic peptide (ANP), which indirectly regulate the HPA system, also may modulate the intensity of craving or the intensity of the alcohol withdrawal syndrome. Although most of the currently available data demonstrate association rather than causality between neuroendocrine changes and alcohol‐related behaviours, they do provide testable hypotheses and open up perspectives of treating alcohol dependence via manipulation of the neuroendocrine axis.
Gender difference in the pancreatic trypsinogen response to ethanol withdrawal in rat pups
Authors: García‐benítez O , Delgado‐Villa MJ , Murillo ML , Carreras O 
Published: October 2006

AbstractThis study was designed to examine the effects of ethanol withdrawal on offspring rats that consumed ethanol during gestation and lactation, in order to examine whether there was an improvement in pancreatic trypsinogen and lipase activities at 2 months postpartum with respect to offspring that fed on ethanol until death. A second purpose for our study was to determine if a folic acid supplement during gestation and lactation was sufficient or insufficient to reverse the negative effects of ethanol consumption. Both genders were used with the aim of investigating any differential pancreatic behaviour. The animals were randomized into five groups: the control group (CG) received water and a basic rat diet during pregnancy, lactation and growth; the ethanol group (EG) was fed an ethanol diet during pregnancy, the suckling period and growth until death; the ethanol ‐ water group's (E + WG) ethanol was eliminated after lactation; The ethanol ‐ folic acid group (E + FG) received a folic acid supplemented diet during pregnancy and the suckling period and in the ethanol + folic acid group (E + FG + FG) this supplementation continued during growth. Our results showed that ethanol administration or ethanol withdrawal did not significantly alter lipase activity in the pancreas. Ethanol administration decreased trypsinogen levels in the pancreas of males and females. However, in males, as opposed to females, the withdrawal of ethanol did not recover the values of pancreatic trypsinogen content, nor did a folic acid supplementation significantly alter the parameters we studied. Our treatment produced no effect on lipase levels. There was a gender‐related difference in pancreatic trypsinogen content, the implication being that in future all results on exocrine pancreas function in male and female animals should be analysed separately.