Fast Initiation Research Articles

Quantum-Dot-Spin Single-Photon Interface

Using background-free detection of spin-state-dependent resonance fluorescence from a single-electron charged quantum dot with an efficiency of 0.1%, we realize a classical single spin-photon interface where the detection of a scattered photon with 300ps time resolution projects the quantum dot spin to a definite spin eigenstate with fidelity exceeding 99%. The bunching of resonantly scattered photons reveals information about electron spin dynamics. High-fidelity fast spin-state initialization heralded by a single photon enables the realization of quantum information processing tasks such as nondeterministic distant spinentanglement. Given that we could suppress the measurement backaction to well below the natural spin-flip rate, realization of a quantum nondemolition measurement of a single spin could be achieved by increasing the fluorescence collection efficiency by a factor exceeding 10 using a photonic nanostructure.

Climatic influence on peatland formation and lateral expansion in sub‐arctic Fennoscandia

Weckström, J., Seppä, H. & Korhola, A. 2010: Climatic influence on peatland formation and lateral expansion in sub‐arctic Fennoscandia. Boreas, Vol. 39, pp. 761–769. 10.1111/j.1502‐3885.2010.00168.x. ISSN 0300‐9843.The initiation and lateral expansion patterns of five small sub‐arctic peatlands in the Fennoscandian tree‐line region were studied by 21 accelerator mass spectrometry (AMS) 14C‐dated basal‐peat samples representing three to six dates per site. The radiocarbon dates were converted to calendar years and are based on the median probability. When combined with earlier basal‐peat dates from the region, four distinctive periods can be observed in the cumulative record of the dates. The early Holocene, from c. 10 000 to 8000 cal. yr BP, was characterized by the fast initiation and rapid expansion of peatlands, whereas at 8000–4000 cal. yr BP lateral expansion was modest. The most intensive period of peatland expansion occurred at the beginning of the late Holocene at c. 4000 to 3000 cal. yr BP, after which it slowed down towards the present. All these periods are in rough agreement with the main Holocene climatic periods in the area, namely the relatively warm and moist early Holocene, the warm and dry Holocene thermal maximum (HTM) at 8000–4000 cal. yr BP, and the start of the cooler and moister trend (neoglacial cooling) from c. 4000 cal. yr BP to the present, indicating a broad‐scale climatic control on the lateral growth of sub‐arctic peatlands in Fennoscandia. In order to study the lateral expansion of peatlands and to evaluate their Holocene succession patterns, more studies based on multiple dates from the same peatland are needed.

Copeptin Improves Early Diagnosis of Acute Myocardial Infarction

Early identification of myocardial infarction in chest pain patients is crucial to identify patients at risk and to maintain a fast treatment initiation. The aim of the current investigation is to test whether determination of copeptin, an indirect marker for arginin-vasopressin, adds diagnostic information to cardiac troponin in early evaluation of patients with suspected myocardial infarction. Between January 2007 and July 2008, patients with suspected acute coronary syndrome were consecutively enrolled in this multicenter study. Copeptin, troponin T (TnT), myoglobin, and creatine kinase-myocardial band were determined at admission and after 3 and 6 h. Of 1,386 (66.4% male) enrolled patients, 299 (21.6%) had the discharge diagnosis of acute myocardial infarction, 184 (13.3%) presented with unstable angina, and in 903 (65.2%) an acute coronary syndrome could be excluded. Combined measurement of copeptin and TnT on admission improved the c-statistic from 0.84 for TnT alone to 0.93 in the overall population and from 0.77 to 0.9 in patients presenting within 3 h after chest pain onset (CPO) (p < 0.001). In this group the combination of copeptin with a conventional TnT provided a negative predictive value of 92.4%. In triage of chest pain patients, determination of copeptin in addition to troponin improves diagnostic performance, especially early after CPO. Combined determination of troponin and copeptin provides a remarkable negative predictive value virtually independent of CPO time and therefore aids in early and safe rule-out of myocardial infarction.

CD169+ macrophages present lipid antigens to mediate early activation of iNKT cells in lymph nodes

Invariant NKT (iNKT) cells are involved in host defence against microbial infections. While it is known that iNKT cells recognize glycolipids presented by CD1d, how and where they encounter antigen in vivo remains unclear. We used multi-photon microscopy to visualize the dynamics and activation of iNKT cells in lymph nodes. Following antigen administration, iNKT cells become confined in a CD1d-dependent manner in close proximity to subcapsular sinus CD169+ macrophages. These macrophages retain, internalize and present lipid antigen, and are required for iNKT cell activation, cytokine production and expansion. Thus, CD169+ macrophages can act as bona fide antigen presenting cells controlling early iNKT cell activation and favouring fast initiation of immune responses.

Fast construction of panoramic images for cystoscopic exploration

Cystoscopy is used as a reference clinical examination in the detection and visualization of pathological bladder lesions. Evolution observation and analysis of these lesions is easier when panoramic images from internal bladder walls are used instead of video sequences. This work describes a fast and automatic mosaicing algorithm applied to cystoscopic video sequences, where perspective geometric transformations link successive image pairs. This mosaicing algorithm begins with a fast initialization of translation parameters computed by a cross-correlation of images, followed by an iterative optimization of transformation parameters. Finally, registered images are projected onto a global common coordinate system. A quantifying test protocol applied over a phantom yielded a mosaicing mean error lower than 4 pixels for a 1947 × 1187 pixels panoramic image. Qualitative evaluation of 10 panoramic images resulting from videos of clinical cystoscopies was performed. An analysis performed over translation values from these clinical sequences ( in vivo) is used to modify the mosaicing algorithm to be able to do a dynamic selection of image pairs. Construction time of panoramic images takes some minutes. At last, algorithm limits are discussed.

Exposure to water increased pollen longevity of pondweed (Potamogeton spp.) indicates different mechanisms ensuring pollination success of angiosperms in aquatic habitat

Pollen longevity in seven Potamogeton species representing different pollination systems (anemophily, epihydrophily and hydroautogamy) was assessed both under aerial condition and in contact with water to investigate how water impacts the sexual reproduction in these aquatic taxa. Stainability of pollen with MTT was considered as an indicator of pollen viability. The half-life of pollen longevity was calculated using exponential decay regression. Overall, pollen viability decreased relatively rapidly with time. Pollen grains of obligate anemophilic species had lower initial viability and shorter half-lives than those of facultative anemophilic species. Pollen in these latter species may take more time to reach the stigma. The pollen of Potamogeton may be categorized as partially hydrated pollen owing to its generally spherical shape and lack of furrows, rapid loss of viability, and fast pollen tube initiation. The half-life is positively correlated with pollen size. Smaller-sized grains are at greater risk of desiccation than larger grains. In contrast with the situation observed in most terrestrial angiosperms, contact with water increases pollen longevity in Potamogeton species. In our present study the half-lives of pollen longevity of Potamogeton species in which the pollen had come into contact with water (mean of 10.65 h) were markedly higher than those under aerial conditions (mean of 5.79 h, t = 2.622, P = 0.039). The results of our study contradict a widely held belief that water is detrimental to pollen viability in angiosperms and furthermore indicate that close proximity to water results in selection for wettability. The transition to a hydrated status together with its morphology, make Potamogeton pollen more adapted to the aquatic environment and thus serves to ensure reproductive process. Results of our present study may have direct implications for understanding the evolution of the sexual reproductive system in aquatic angiosperms.

Data Association Approach for Two Dimensional Tracking Based on Bearing-Only Measurements in Clutter Environment

This paper mainly studies angle-measurement based data association algorithm to overcome the existing problems in the applications of traditional association approaches for bearing-only target locating and tracking system. First, this paper proposes a fast track initiation approach for the system using a single passive sensor. In this approach, the rules of screening out threatening targets are set by analyzing the characteristics of target motion in two dimensional bearing-only coordinates. And the track initiation of threatening targets is implemented in the shortest time based on a modified heuristic algorithm using these rules. Then, other target tracks are initialized based on a logic-based algorithm in two dimensional bearing-only coordinates as a supplement. At last, by deeply studying different point-track association algorithms and comparing the association effect between JPDA and NNDA in bearingonly coordinate, suitable angle-measurement based association algorithm is presented. As the results, the confirming efficiency of the bearing-only measurements is improved and false tracking with the dense clutter is limited. The application of this algorithm has effectively resolved the track association problem of the bearing-only tracking using a single passive sensor. The application of the proposed approach in a simulation system proves its effectiveness and practicability.

Pseudoperiodic “Living” and/or Controlled Cationic Ring-Opening Copolymerization of Oxetane with Tetrahydropyran: Microstructure of Polymers vs Kinetics of Chain Growth

The “living” and/or controlled cationic ring-opening bulk copolymerization of oxetane (Ox) with tetrahydropyran (THP) (cyclic ether with no homopolymerizability) at 35 °C was examined using ethoxymethyl-1-oxoniacyclohexane hexafluoroantimonate (EMOA) and (BF3·CH3OH)THP as fast and slow initiator, respectively, yielding living and nonliving polymers with pseudoperiodic sequences (i.e., each pentamethylene oxide fragment inserted into the polymer is flanked by two trimethylene oxide fragments). Good control over number-average molecular weight (Mn up to 150 000 g mol−1) with molecular weight distribution (MWD ∼ 1.4−1.5) broader than predicted by the Poison distribution (MWDs > 1 + 1/DPn) was attained using EMOA as initiating system, i.e., C2H5OCH2Cl with 1.1 equiv of AgSbF6 as a stable catalyst and 1.1 equiv of 2,6-di-tert-butylpyridine used as a non-nucleophilic proton trap. With (BF3·CH3OH)THP, a drift of the linear dependence Mn(GPC) vs Mn(theory) to lower molecular weight was observed together with the production of cyclic oligomers, ∼3−5% of the Ox consumed in THP against ∼30% in dichloromethane. Structural and kinetics studies highlighted a mechanism of chains growth where the rate of mutual conversion between “strain ACE species” (chain terminated by a tertiary 1-oxoniacyclobutane ion, A1) and “strain-free ACE species” (chain terminated by a tertiary 1-oxoniacyclohexane ion, T1) depends on the rate at which Ox converts the stable species T1 (kind of “dormant” species) into a living “propagating” center A1 (i.e., kaapp[Ox]). The role of the THP solvent associated with the suspension of irreversible and reversible transfer reactions to polymer, when the polymerization is initiated with EMOA, was predicted by our kinetic considerations. The activation−deactivation pseudoequilibrium coefficient (Qt) was then calculated in a pure theoretical basis. From the measured apparent rate constant of Ox (kOxapp) and THP (kTHPapp = ka(endo)app) consumption, Qt and reactivity ratio (kp/kd, ka(endo)/ka(exo), and ks/ka(endo)) were calculated, which then allow the determination of the transition rate constant of elementary step reactions that governs the increase of Mn with conversion.

Registration Combining Wide and Narrow Baseline Feature Tracking Techniques for Markerless AR Systems

Augmented reality (AR) is a field of computer research which deals with the combination of real world and computer generated data. Registration is one of the most difficult problems currently limiting the usability of AR systems. In this paper, we propose a novel natural feature tracking based registration method for AR applications. The proposed method has following advantages: (1) it is simple and efficient, as no man-made markers are needed for both indoor and outdoor AR applications; moreover, it can work with arbitrary geometric shapes including planar, near planar and non planar structures which really enhance the usability of AR systems. (2) Thanks to the reduced SIFT based augmented optical flow tracker, the virtual scene can still be augmented on the specified areas even under the circumstances of occlusion and large changes in viewpoint during the entire process. (3) It is easy to use, because the adaptive classification tree based matching strategy can give us fast and accurate initialization, even when the initial camera is different from the reference image to a large degree. Experimental evaluations validate the performance of the proposed method for online pose tracking and augmentation.

Optical rotation of heavy hole spins by non-Abelian geometrical means

A non-Abelian geometric method is proposed for rotating of heavy hole spins in a singly positive charged quantum dot in Voigt geometry. The key ingredient is the delay-dependent non-Abelian geometric phase, which is produced by the nonadiabatic transition between the two degenerate dark states. We demonstrate, by controlling the pump, the Stokes and the driving fields, that the rotations about $y$- and $z$-axes with arbitrary angles can be realized with high fidelity. Fast initialization and heavy hole spin state readout are also possible.

Improved Molecular Weight Control in Ring‐Opening Metathesis Polymerization (ROMP) Reactions with Ru‐Based Olefin Metathesis Catalysts Using N Donors and Acid: A Kinetic and Mechanistic Investigation

The effect of the addition of H(3)PO(4) on the ROMP activity of cyclooctene (COE) with first- [Cl(2)(PCy(3))(2)Ru=CHPh] and second-generation [(H(2)IMes)Cl(2)(PCy(3))Ru=CHPh] Grubbs' catalysts 1 and 4 (Cy=cyclohexyl, Ph=phenyl, Mes=2,4,6-trimethylphenyl (mesityl)), their inhibited mixtures with 1-methylimidazole (MIM), as well as their isolated bis-N,N'-dimethylaminopyridine (DMAP) derivatives [Cl(2)(PCy(3))(DMAP)(2)Ru=CHPh)] (5 b) and [Cl(2)(H(2)IMes)(DMAP)(2)Ru=CHPh] (7 b) (DMAP=dimethylaminopyridine), a novel catalyst, has been investigated. The studies include the determination of their initiation rates, as well as a determination of the molecular weights and molecular weight distributions of the polymers obtained with these catalysts and catalyst mixtures from the exo-7-oxanorbornene derivative 11. The structure of catalyst 7 b was confirmed by means of X-ray diffraction. All N-donor-bearing catalysts or N-donor-containing catalyst mixtures not only exhibited elevated activity in the presence of acid, but also increased initiation rates. Using the reversible inhibition/activation protocol with MIM and H(3)PO(4) enabled us to conduct controlled ROMP with catalyst 4 producing the isolated exo-7-oxanorbornene-based polymer 12 with predetermined molecular weights and narrow molecular weight distributions. This effect was based on fast and efficient catalyst initiation in contrast to the parent catalyst 4. Hexacoordinate complex 5 b also experienced a dramatic increase in initiation rates upon acid-addition and the ROMP reactions became well-controlled in contrast to the acid-free reaction. In contrast, complex 7 b performs well-controlled ROMP in the absence of acid, whereas the polymerization of the same monomer becomes less controlled in the presence of H(3)PO(4). The closer evaluation of catalysts 5 b and 7 b demonstrated that their initiation rates exhibit a linear dependency on the substrate concentration in contrast to catalysts 1 and 4. As a consequence, their initiation rates are determined by an associative step, not a dissociative step as seen for catalysts 1 and 4. A feasible associative metathesis initiation mechanism is proposed.

Abstract 5021: Copeptin Improves Early Diagnosis of Acute Myocardial Infarction

Introduction: Early diagnosisof myocardial infarction in chest pain patients is crucial to identify patients at risk and to maintain a fast treatment initiation. Background: Aim of the current investigation is to test whether determination of copeptin, an indirect marker for arginin-vasopressin, adds diagnostic information to conventional troponin in early evaluation of patients with suspected myocardial infarction. Methods: Between 06/2006 and 03/2008 patients with suspected acute coronary syndrome were enrolled consecutively. Copeptin, troponin T, myoglobin and creatine kinase-MB were determined at admission and after 3 and 6 hours. Results: Of 1293 (66.1% male) enrolled patients 244 (18.9%) had the discharge diagnosis of acute myocardial infarction, 211 (16.3%) presented with unstable angina and in 838 (64.8%) patients an acute coronary syndrome could be excluded. Combined measurement of copeptin and troponin T at admission improved the c-statistic from 0.85 for troponin T alone to 0.94 in the overall population and from 0.77 to 0.91 in patients presenting within 3 hours after chest pain onset. In this group the combination provided an excellent negative predictive value of 91.1%. Conclusions: In triage of chest pain patients determination of copeptin in addition to conventional troponin T improves diagnostic performance, especially early after chest pain onset. Combined determination of troponin T and copeptin provides an excellent negative predictive value virtually independent of chest pain onset time and therefore allows an early and safe rule-out of myocardial infarction.

Atomic Layer Deposition for All-Solid-State 3D-Integrated Batteries

All-solid-state 3D integrated batteries can reach the energy storage capacity required for future wireless devices by exploiting the third dimension. Conformal deposition techniques such as atomic layer deposition (ALD) are needed to deposit the battery materials. In this work, the current development of ALD processes for 3D integrated batteries is reviewed. We have developed both the TiN diffusion barrier and Pt cathode current collector processes. TiN showed good barrier properties in 3D, although a higher than expected charge density was observed, which could be attributed to a lower thickness and/or different material properties at the bottom of the 3D structures. The remote plasma ALD process for Pt showed fast growth initiation and good adhesion of the films. Furthermore, sufficient step coverage for the battery application was found. ALD is also potentially able to deposit the active battery layers, although the deposition of Li-containing materials is expected to be challenging.

Role of the liver in glucose homeostasis in PI 3-kinase p85α-deficient mice

Phosphoinositide 3-kinase (PI3K) p85alpha-deficient mice exhibit hypoglycemia as a result of increased insulin sensitivity and glucose uptake in peripheral tissues. Although PI3K is central to the metabolic actions of insulin, its mechanism of action in liver is not well understood. In the present study, we investigated hepatic insulin signaling and glucose homeostasis in p85alpha-deficient and wild-type mice. In the livers of p85alpha-deficient mice, p50alpha played a compensatory role in insulin-stimulated PI3K activation by binding to insulin receptor substrate (IRS)-1/2. In p85alpha-deficient mice, the ratio of p50alpha over p110 catalytic subunit of PI3K in the liver was higher than in the muscles. PI3K activity associated with IRS-1/2 was not affected by the lack of p85alpha in the liver. Insulin-stimulated Akt and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) activities in the liver were similar in p85alpha-deficient and wild-type mice. A hyperinsulinemic-euglycemic clamp study revealed that the glucose infusion rate and the rate of disappearance were higher in p85alpha-deficient mice than in wild-type mice but that endogenous glucose production tended to be higher in p85alpha-deficient mice than in wild-type mice. Consistent with this finding, the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase in livers after fasting was higher in p85alpha-deficient mice than in wild-type mice. After mice were fasted, the intrahepatic glucose-6-phosphate level was almost completely depleted in p85alpha-deficient mice. The glycogen content fell to nearly zero as a result of glycogenolysis shortly after the initiation of fasting in p85alpha-deficient mice. The absence of an increase in insulin-stimulated PI3K activation in the liver of p85alpha-deficient mice, unlike the muscles, may be associated with the molecular balance between the regulatory subunit and the catalytic subunit of PI3K. Gluconeogenesis was rather elevated in p85alpha-deficient mice, compared with in wild-type mice, and the liver seemed to partially compensate for the increase in glucose uptake in peripheral tissues.

Three Types of Tropical Waves Related to Tropical Cyclogenesis Over the Western North Pacific

Abstract The present study applies a space-time filter to identify three dominant types of tropical waves: Mad-den-Julian oscillations (MJOs), equatorial Rossby (ER) waves, and tropical depression (TD)-type disturbances. The impacts of these waves on tropical cyclones (TCs) were investigated based on 131 observations during the period 2000−07. The results suggest that 72% of TC geneses were related to the joint impacts of more than one type of wave. The composites for cases in different cate-gories reveal that TCs related to the concurrence of the three types of waves have strong and large initial vortices at the time of TC genesis. In the absence of the MJO, ER- and TD-related TC genesis, embedded in easterly flow, exhibits a relatively fast initiation process and gives rise to a relatively small scale vortex. In contrast, without the ER wave contribution, TCs associated with ER and TD waves did not require strong convection at the time of genesis because an initial vortex can rapidly develop in the MJO active phase through persistent energy transfer. The MJO-related TC geneses were scattered in geo-graphic distribution, as opposed to the clustered and eastward shift observed for genesis cases without contri-butions from MJOs.

Cosmopolitanism, global social justice and gender equality in education

This article attempts to locate approaches to understanding gender, education and notions of the international within debates on global social justice and cosmopolitanism. It looks at the work of three feminist scholars (Martha Nussbaum, Onora O'Neill and Iris Young) on this theme, draws out some ways in which they engage critiques of cosmopolitanism and considers some of the implications of their work for thinking about gender equality and comparative education. Two examples of work on gender equality in education at global level are assessed: the attempt to introduce gender dimensions into assessments of global financing for Education for All through the Fast Track Initiative and improved forms of monitoring of gender equality in education at national and international levels. The difficulties encountered and some of the implications for understanding discussions of cosmopolitanism are outlined, together with a case for strengthening and supporting work on gender and global social justice that takes participation and ethical reflection as a central concern.

Registration based on Euclidean reconstruction and natural features tracking for augmented reality systems

PurposeThe purpose of this paper is to propose a novel registration method using Euclidean reconstruction and natural features tracking for AR‐based assembly guidance systems.Design/methodology/approachThe method operates in two steps: offline Euclidean reconstruction and online tracking. Offline stage involves obtaining the structure of scene using Euclidean reconstruction technique. The classification trees are constructed using affine transform for online initialization. In tracking, the classification‐based wide baseline matching strategy and Td,d test are used to get a fast and accurate initialization for the first frame after which a modified optical flow tracker is used to fulfill the task of feature tracking in the real‐time video sequences. The four specified points are transferred to the current image to compute the registration matrix for augmentation.FindingsFirstly, Euclidean reconstruction was used instead of projective reconstruction to get the projections of predefined features. Compared with the six points needed in projective reconstruction‐based method, this method can run normally even when only four features are successfully tracked. Secondly, an adaptive strategy was proposed to adjust the classification trees using the tracked features in online stage by which one can initialize or reinitialize the system, even with large difference between the first and reference images.Originality/valueSome indoor and outdoor experiments are provided to validate the performance of the proposed method.

Pitting mechanism on an austenite stainless steel nanocrystalline coating investigated by electrochemical noise and in-situ AFM analysis

The pitting corrosion behavior of an austenite stainless steel with polycrystalline (PC) and nanocrystalline (NC) microstructure in 3.5% NaCl solution was investigated by electrochemical noise (EN) and in-situ atomic force microscopy (AFM) under anodic potential. The power spectral density (PSD) and wavelet transform have been employed to analyze the EN data. The pitting corrosion resistance of the NC coating was much higher than that of the PC alloy, with different pitting mechanisms observed for both specimens; a slow metastable pit generation and healing for the PC alloy and a fast metastable pit initiation and death for the NC coating. There was good conformity between the EN and the in-situ AFM analysis. The pitting corrosion mechanism has been discussed according to the EN analysis and the in-situ AFM observations.

In Vitro Propagation and Conservation of Dendrobium lituiflorum Lindl Through Protocorm-Like Bodies

Axillary buds obtained from 5-month-old in vitro growing plants of Dendrobium lituiflorum Lindl were cultured in Murashige and Skoog (MS) medium supplemented with different concentrations of 2,4-D. Fastest initiation (13.3 days) of protocormlike bodies (PLBs) was observed in cultures containing MS medium supplemented with 0.5 mg l−1 2,4-D. Maximum explant response of 83% was also observed in the same medium. PLBs obtained in MS medium containing 0.5 mg l−1 2,4-D showed maximum regeneration potential of seedlings (19 explant−1) when subcultured in MS medium. Well developed shoots and roots of the seedlings were obtained in the medium containing 0.5 mg l−1 each of NAA and BAP, in combination. Encapsulated PLBs of D. lituiflorum could be stored at 8°C for 90 days with 80% regeneration. However, it was observed that regeneration potential of encapsulated PLBs reduced with further storage. Seventy seven per cent hardened plants survived and bloomed after 2.5 years of hardening.

Fast Mixing and Reaction Initiation Control of Single-Enzyme Kinetics in Confined Volumes

A device with femtoliter-scale chambers and controlled reaction initiation was developed for single-molecule enzymology. Initially separated substrate and enzyme streams were rapidly mixed in a microfluidic device and encapsulated in an array of individual microreactors, allowing for enzyme kinetics to be monitored with millisecond dead times and single-molecule sensitivity. Because the arrays of chambers were fabricated by micromolding in PDMS, the chambers were monodisperse in size, and the chamber volume could be systematically controlled. Microreactors could be purged and replenished with fresh reactants for consecutive rounds of observation. Repeated experiments with statistically identical initial conditions could be performed rapidly, with zero cross-talk between chambers in the array.