bluuebunny/crossref_metadata_2025_split huggingface dataset:
The rise of spin noise spectroscopy in semiconductors: From acoustic to GHz frequencies
Authors: Hübner Jens , Berski Fabian , Dahbashi Ramin , Oestreich Michael 
Published: January 2014

This article gives an overview on the advance of spin noise spectroscopy (SNS) in semiconductors in the past 8 years from the first measurements in bulk n‐GaAs [Oestreich et al., Phys. Rev. Lett. 95, 216603 (2005)] up to the recent achievement of optical detection of the intrinsic spin fluctuations of a single hole confined in an individual self‐assembled quantum dot [Dahbashi et al., arXiv:1306.3183 (2013)]. We discuss the general technical implementation of optical SNS and the invaluable profit of the introduction of real‐time fast Fourier transform analysis into the data acquisition. By now, the full spin dynamic from the milli‐ to picosecond timescales can be addressed by SNS and the technique quickly strides ahead to enable real quantum non‐demolition measurements in semiconductors. Spin noise spectra recorded in 2005 in bulk n‐GaAs with approximately 109 electron spins (Oestreich et al.) and 2013 (Dahbashi et al.) for a single hole spin. The integration time for the latter is more than a factor of 40 shorter due to the significant advances in the measurement technique.
Photoluminescence of m‐plane GaN grown on m‐plane sapphire by MOCVD
Authors: Paduano Qing S. , Weyburne David W. , Look David C. 
Published: January 2014

AbstractThe photoluminescence of m‐plane GaN grown on m‐plane sapphire substrate by MOCVD is reported. The defect related emissions with temperature and excitation power dependence are detailed. In addition to the near band‐edge emission (at ∼3.472 eV), two major defect‐related bands (D1∼3.43 eV and D2∼3.34 eV) are dominant in the low temperature spectra. The D1 emission exhibits thermal quenching with two activation energies (8 and 30 meV), similar to that of a‐plane GaN grown on r‐plane sapphire. The D2 band was found to consist of a complex overlap of multiple emissions. By fitting the asymmetric band using multiple Gaussian functions, the extracted emission at ∼3.34 eV was shown to have thermal activation energy ∼17–20 meV. This emission exhibits different behavior from that of D2 in a‐plane GaN in temperature and excitation power dependency, indicating the possible involvement of different defects due to the changes in growth characteristics. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐polar GaN quantum dots integrated into high quality cubic AlN microdisks
Authors: Bürger M. , Callsen G. , Kure T. , Hoffmann A. , Pawlis A. , Reuter D. , As D. J. 
Published: January 2014

AbstractWe report on lasing of non‐polar GaN quantum dots which are integrated into novel cubic AlN microdisks. Optical spectroscopy of freestanding microdisks at low temperature (∼10 K) revealed distinct whispering gallery modes with quality factors up to Q ∼3000 in the high energy range around ∼4 eV of microdisks with a diameter of 4 µm. Furthermore, we obtained S‐shaped curves of the integral mode intensity, accompanied by a significant linewidth narrowing in power dependent micro‐photoluminescence experiments. The spontaneous emission coupling factors were determined to β = 0.26 and β = 0.58 with respect to the radial order of the resonator modes. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MOVPE growth of AlxGa1‐xN with x ∼ 0.5 on epitaxial laterally overgrown AlN/sapphire templates for UV‐LEDs
Authors: Knauer A. , Zeimer U. , Kueller V. , Weyers M. 
Published: January 2014

AbstractThe crystalline perfection of AlxGa1‐xN layers with Al content of x ∼ 0.5 on epitaxial laterally overgrown (ELO) AlN with low defect density was investigated by spatially and spectrally resolved cathodoluminescence, scanning electron and atomic force microscopy. Cathodoluminescence mapping reveals compositional variations caused by different Ga incorporation during growth over macro‐steps resulting from step bunching on the ELO‐AlN. Introducing AlN interlayers as marker the influence of the macrosteps as well as of the growth rate on the development of Ga‐rich regions was studied. With increasing growth rate from 0.2 to 1 µm/h the spatial extension of the Ga‐rich regions is strongly reduced. At the same time the difference in Ga content is increased. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Well‐Being and Personal Growth in Mothers of Full‐Term and Pre‐Term Singletons and Twins
Authors: Noy Adi , Taubman – Ben‐Ari Orit , Kuint Jacob 
Published: January 2014

AbstractThe present study examined well‐being and personal growth in mothers (n = 414) 1 year after childbirth. We examined the contribution of the event characteristics (birth of singletons or twins, full‐ or pre‐term babies, first or non‐first child, spontaneous pregnancy or fertility treatments and infant temperament), internal resources (attachment anxiety and avoidance) and external resources (marital quality and maternal grandmother's support). Regressions indicated that having a first child, child's easier temperament, lower attachment anxiety and avoidance, grandmother's emotional support and some aspects of the spousal relationships contributed to well‐being. Personal growth was found to be related to the birth of a pre‐term baby or babies, positively associated with maternal grandmother's support, and the marital quality of parenthood, and negatively with mothers' education. Beyond the findings that well‐being and personal growth are related to the availability of certain resources, the current study demonstrates that the two outcomes are separate phenomena that reveal different patterns of associations with other variables. Several explanations for the findings are proposed, and practical implications are discussed. Copyright © 2014 John Wiley & Sons, Ltd.
Asymmetric Nitrene Transfer Reactions: Sulfimidation, Aziridination and C–H Amination Using Azide Compounds as Nitrene Precursors
Authors: Uchida Tatsuya , Katsuki Tsutomu 
Published: January 2014

AbstractNitrogen functional groups are found in many biologically active compounds and their stereochemistry has a profound effect on biological activity. Nitrene transfer reactions such as aziridination, C–H bond amination, and sulfimidation are useful methods for introducing nitrogen functional groups, and the enantiocontrol of the reactions has been extensively investigated. Although high enantioselectivity has been achieved, most of the reactions use (N‐arylsulfonylimino)phenyliodinane, which co‐produces iodobenzene, as a nitrene precursor and have a low atom economy. Azide compounds, which give nitrene species by releasing nitrogen, are ideal precursors but rather stable. Their decomposition needs UV irradiation, heating in the presence of a metal complex, or Lewis acid treatment. The examples of previous azide decomposition prompted us to examine Lewis acid and low‐valent transition‐metal complexes as catalysts for azide decomposition. Thus, we designed new ruthenium complexes that are composed of a low‐valent Ru(II) ion, apical CO ligand, and an asymmetry‐inducing salen ligand. With these ruthenium complexes and azides, we have achieved highly enantioselective nitrene transfer reactions under mild conditions. Recently, iridium–salen complexes were added to our toolbox.
The Origins of Homochirality Examined by Using Asymmetric Autocatalysis
Authors: Soai Kenso , Kawasaki Tsuneomi , Matsumoto Arimasa 
Published: January 2014

AbstractPyrimidyl alkanol was found to act as an asymmetric autocatalyst in the enantioselective addition of diisopropylzinc to pyrimidine‐5‐carbaldehyde. Asymmetric autocatalysis of 2‐alkynylpyrimidyl alkanol with an extremely low enantiomeric excess (ca. 0.00005% ee) exhibits enormous asymmetric amplification to afford the same compound with >99.5% ee. This asymmetric autocatalysis with amplification of ee has been employed to examine the validity of proposed theories of the origins of homochirality. Circularly polarized light, quartz, sodium chlorate, cinnabar, chiral organic crystals and spontaneous absolute asymmetric synthesis were considered as possible candidates for the origin of chirality; each could act as a chiral source in asymmetric autocatalysis. Asymmetric autocatalysis can discriminate the isotope chirality arising from the small difference between carbon (carbon‐13/carbon‐12) and hydrogen (D/H) isotopes. Cryptochiral compounds were also discriminated by asymmetric autocatalysis.
Organoplatinum‐Mediated Synthesis of Cyclic π‐Conjugated Molecules: Towards a New Era of Three‐Dimensional Aromatic Compounds
Authors: Yamago Shigeru , Kayahara Eiichi , Iwamoto Takahiro 
Published: January 2014

AbstractThis article describes the most recent developments in the synthesis of three‐dimensional π‐conjugated molecules and the elucidation of their properties made by our research group. Various cycloparaphenylenes (CPPs) of different sizes and a cage‐like 3D molecule were synthesized based on the platinum‐mediated assembly of π‐units and subsequent reductive elimination of platinum. The assembly of π‐units by this method mimics the self‐assembly process for the formation of supramolecular ligand–metal complexes with 3D cages and polyhedral structures. Furthermore, reductive elimination of platinum successfully took place with high efficiency, despite the high strain energy of the target molecule. Several size‐dependent physical properties of CPPs, namely the photophysical, redox, and host–guest chemistries, were also clarified. These results are of use for a molecular‐level understanding of CNT physical properties as well as fullerene peapods. Theoretical and electrochemical studies suggest that small CPPs and their derivatives should be excellent lead compounds for molecular electronics.
Development of Chiral Catalysts for Mukaiyama Aldol Reactions in Aqueous Media
Authors: Kitanosono Taku , Kobayashi Shū 
Published: January 2014

AbstractSince the discovery of the Mukaiyama aldol reaction in 1973, tremendous efforts have been made to develop a definitive catalyst that catalyzes asymmetric Mukaiyama aldol reactions under mild conditions with broad substrate tolerance. Forty years later, an exhaustive search for a water‐compatible Lewis acid was able to uncover the hidden potential of iron(II) and bismuth(III), leading to the establishment of broadly applicable and versatile catalytic systems for asymmetric Mukaiyama aldol reactions in aqueous media. The ternary catalytic system was able to expand the substrate generality considerably as the most distinguished catalyst ever reported. The superiority of this methodology over conventional methods has also been demonstrated in terms of high catalytic activity, simplicity of experimental procedures, and a wide substrate range including aqueous aldehydes, for which the stereochemistry had been regarded as difficult to control. Furthermore, a facile synthesis of the chiral ligand underscores its versatility. The reaction did not proceed at all without use of water. In the postulated mechanism, water plays prominent roles in: (1) producing the active metal complexes with a high water‐exchange rate constant (3.2 × 106) to activate substrates effectively and to catalyze the reaction through a rapid proton transfer on the order of picoseconds; (2) facilitating the catalytic turnover with simultaneous desilylation as direct access to aldol adducts or facile recovery of active metal complexes; and (3) stabilizing rigid transition states composed of metal complexes and reactants through entropy‐driven aggregation derived from the highest cohesive energy density.
On providing wormhole‐attack‐resistant localization using conflicting sets
Authors: Chen Honglong , Lou Wei , Wang Zhi 
Published: January 2014

AbstractWormhole attack is a severe attack that can be easily mounted on a wide range of wireless networks without compromising any cryptographic entity or network node. In the wormhole attack, an attacker sniffs packets at one point in the network and tunnels them through the wormhole link to another point. Such kind of attack can deteriorate the localization procedure in wireless sensor networks. In this paper, we first analyze the impacts of the wormhole attack on the localization procedure. Then, we propose a secure localization scheme against the wormhole attacks called SLAW including three phases: wormhole attack detection, neighboring locators differentiation, and secure localization. The main idea of the SLAW is to build a so‐called conflicting set for each locator based on the abnormalities during the message exchanges, which can be used to differentiate the dubious locators to achieve secure localization. We first consider the simplified system model in which there is no packet loss and all the nodes have the same transmission range. We further consider the general system model where the packet loss exists and different types of nodes have different transmission radii. We conduct the simulations to illustrate the effectiveness of the proposed secure localization scheme and compare it with the existing schemes under different network parameters. Copyright © 2014 John Wiley & Sons, Ltd.
Incorporating foray behavior into models estimating contact risk between bighorn sheep and areas occupied by domestic sheep
Authors: O'brien Joshua M. , O'brien Chans S. , MCcarthy Clinton , Carpenter Tim E. 
Published: January 2014

ABSTRACTRespiratory disease epidemics are considered a primary factor limiting bighorn sheep (Ovis canadensis) populations in most of the western United States. Diverse sources of evidence indicate that domestic sheep harbor pathogens that cause fatal pneumonia in bighorn sheep, and that contact between the species often leads to respiratory disease and mortality in wild bighorn sheep populations. Managers have long argued that maintaining species separation is essential to conserving bighorn sheep. However, few studies have quantified probability of interspecies contact under different separation‐based management scenarios. We present an approach to estimating relative risk of interspecies contact that uses telemetry data to characterize bighorn sheep home ranges, habitat selection, and the occasional long‐distance exploratory movements (forays) characteristic of the species. We developed this approach to assess probability of bighorn sheep entering domestic sheep allotments on the Payette National Forest in central Idaho, USA, and we present that analysis as a case study. First, a large telemetry data set was used to identify bighorn sheep core herd home ranges and foray characteristics, including frequency, distance traveled, and habitat selection. Observed summer‐season foray probabilities for males and females were, respectively, 0.141 and 0.015 forays per animal per summer, with 50% of foraying males traveling at least 8.1 km and 10% of foraying males traveling at least 21.7 km beyond their core herd home range boundary. Risk of bighorn sheep contact with a domestic sheep allotment was then modeled by combining observed bighorn habitat preferences and movement patterns with geographic data, including habitat suitability and distance of core herd home ranges from domestic sheep allotments. For the domestic sheep grazing alternatives analyzed by the Payette National Forest, modeled contact rates between foraying bighorn sheep and domestic sheep allotments ranged from 0 to 1.33 contacts per year. Managers elsewhere can apply this methodology to estimate risk of interspecies contact based on bighorn sheep space use and habitat preferences. © 2014 The Wildlife Society.
Can the effect of tall structures on birds be isolated from other aspects of development?
Authors: Walters Kimberly , Kosciuch Karl , Jones Jason 
Published: January 2014

ABSTRACTAs technology and energy development increase, undeveloped land and land traditionally used for agriculture now host structures not part of the historical landscape. These structures (e.g., communication towers, transmission lines) are taller than many objects in natural landscapes. Concerns have been raised regarding the effects of tall structures on birds, primarily functional habitat loss due to avoidance. Two hypotheses have been advanced to explain observed patterns of birds near tall structures: increased perceived predation risk and neophobia. We examined the literature (1969–2013) and used a vote‐counting methodology to document 1) the reported direction (positive or negative) of a potential tall‐structure effect, 2) whether the effect of tall structures can be isolated from other effects of development, 3) whether the study design lent itself to drawing a supportable conclusion, and 4) whether the authors suggested a causal mechanism for any observed pattern. We did not detect any consistent response to tall structures, nor did we find evidence to support the two hypotheses. In addition, a structure's “tallness” could not be isolated from other factors associated with development such as human activity. Understanding causal mechanisms is important for management and conservation because observed effects might not be related to the tallness of the structure but to other factors that could be managed, such as timing of construction. Our results suggest that the effect of tall structures on birds is not well understood, and focused studies that examine before‐and‐after effects and specific causal mechanisms are needed to support effective project siting and conservation planning. © 2014 The Wildlife Society.
Maximizing the ecological contribution of conservation banks
Authors: Bunn David A. , Moyle Peter B. , Johnson Christine K. 
Published: January 2014

ABSTRACTIn 1995, California established the first conservation banking program in the United States to provide a new financial mechanism to conserve wildlife and natural communities in rapidly developing regions. Conservation banks are lands protected and managed for conservation of species of concern. Developers may purchase species credits from a conservation bank to offset adverse impacts of development at another site. Conservation banks facilitate pooling of mitigation resources from multiple development projects to protect planned habitat reserves of greater ecological value than can be achieved with project‐by‐project mitigation. In this study, we conducted the first ever assessment of the ecological performance of the California Conservation Banking Program. Specifically, we investigated to what extent conservation banks contribute to achieving regional conservation objectives. We hypothesized that conservation banks within a region should have similarly high ecological values if they are appropriately evaluated and prioritized based on principles of conservation planning. We created a new ecological value metric to evaluate and rank conservation banks and used it to compare potential conservation banks or reserves within a region. We found the ecological value of banks within regions varied and concluded that maximizing the ecological contribution of conservation banks requires prioritization of lands for potential bank sites and reserves. Our analysis identified circumstances where conservation banking is not an appropriate mitigation mechanism to protect rare species and natural communities. We concluded that limited funding for conservation planning should be directed toward regions where species of concern are wide‐ranging, biodiversity is highly variable, threats to species of concern are highly varied, and there are many potential conservation bank sites. © 2014 The Wildlife Society.
Thyroid Surgery without Antibiotic Prophylaxis: Experiences with 1,030 Patients from a Teaching Hospital in China
Authors: Qin Qian , Li Hong , Wang Li‐Bin , Li Ai‐Hui , Chen Li‐Ju , Lu Qiang 
Published: January 2014

AbstractObjectiveOur objective was to evaluate the outcome of thyroidectomy without the use of prophylactic antibiotics. This study was held from January 2005 to May 2012 in a teaching hospital in Dongguan, China.MethodsA total of 1,030 thyroidectomy patients were retrospectively reviewed and basic data were recorded, including age, sex, peri‐operative antibiotic use, type of thyroid surgery done, and post‐operative complications. Either an open approach or an endoscopic approach was performed according to the doctor’s or patient’s preference following a strict aseptic technique. The drain was routinely placed. Any complications were analyzed.ResultsA total of 834 (81 %) females and 196 (19 %) males were included, giving a ratio of 4.2:1. The average age was 38.3 years. The mean operation time was 85.3 min. Pathological type included 818 (79.4 %) nodular goiter, 34 (3.3 %) Graves’ disease, 102 (9.9 %) nodular papillary hyperplasia, 12 (1.2 %) Hashimoto’s disease, 62 (6 %) papillary carcinoma, and 2 (0.2 %) medullary carcinoma. Four patients had postoperative bleeding, four had temporally recurrent nerve paralysis. Only one had wound infection (0.09 %).ConclusionAntibiotic prophylaxis in elective thyroidectomy is not an essential pre‐operation preparation for all patients, if guidelines for antibiotic prophylaxis in clean surgery are adhered to and surgeons have sophisticated skills in the procedure.
Kingella kingae septic arthritis in children: recognising an elusive pathogen
Authors: Williams Nicole , Cooper Celia , Cundy Peter 
Published: January 2014

Purpose Kingella kingae is an increasingly identified cause of musculoskeletal infections in young children. We report our experience with a recently developed polymerase chain reaction (PCR) method and review the clinical course of children diagnosed with K. kingae septic arthritis in a tertiary referral paediatric hospital. Methods All positive cases of K. kingae identified by PCR analysis of synovial fluid from August 2010 until July 2013 were included. A chart review was undertaken to determine history, presentation and management. Results 27 Children (14 male, 13 female) had PCR positive synovial fluid samples for K. kingae with median age of 19 months (range 4 months to 5 years 3 months). The sites of infection were knee (17 cases), hip (2 cases), ankle (5 cases), shoulder (2 cases) and elbow. The median temperature on presentation was 37.1 °C, median peripheral white blood cell count 12.4 (9.9–13.8) × 109/L, erythrocyte sedimentation rate 55 (48–60) mm/h and C-reactive protein 24 (8–47) mg/L. The median synovial fluid white cell count was 21.8 (16.7–45.0) × 109/L. Routine cultures identified K. kingae in only two synovial fluid samples. Two samples were additionally positive for Staphylococcus aureus. Conclusions Kingella kingae is a significant cause of septic arthritis in young children. The authors recommend maintaining a high index of suspicion in young children presenting with joint inflammation, especially if indices of infection are mild. It appears likely that children historically treated with antibiotics for “culture negative” septic arthritis were infected with K. kingae. PCR techniques for detection of K. kingae should be encouraged.