1,114 research outputs found
Soil respiration and net ecosystem production in relation to intensive management in Moso bamboo forests
No full textMoso bamboo forests represent an important forest type commonly found throughout subtropical China and are characterized by fast growing forests, and involves intensive management, such as reclamation, fertilization, and understory removal. However, effects of intensive management on soil respiration (R-S) and net ecosystem production (NEP) remain unclear. In this study, R-S was partitioned into root respiration (R-R), litter respiration (R-L), and soil organic matter derived respiration (R-M) by litter removal and trenching approaches. One-year measurements of respiration rates, soil temperature, and soil moisture were conducted in an unmanaged and an intensively managed stand. Regardless of stand management, R-S and source components increased exponentially with soil temperature and linearly with soil moisture. Temperature sensitivity (Q(10)) ranged from 1.6 to 2.5, with the highest value for R-M, highlighting the importance of R-M in regulating the response of R-S to soil temperature change. Annual R-S, R-R, R-L, and R-M were 32.6, 10.7, 6.9, and 15.0 t CO2 ha(-1) a(-1) for unmanaged stand, compared to 38.6, 12.5, 7.1, and 18.9 t CO2 ha(-1) a(-1) for intensive managed stand, respectively, indicating that intensive management increased R-S by R-R and R-M. Intensive management also increased NEP with 17.2 t CO2 ha(-1) a(-1) for unmanaged stand and 20.4 t CO2 ha(-1) a(-1) for intensive managed stand. This increase was mainly attributed to the increase in net primary production of bamboo forests under intensive management. However, the sustainability of intensive management needs further investigation due to the reduction of soil organic carbon content after intensive management. Forest management associated with the reduction in soil CO2 flux and increase in stand production should be developed for Moso bamboo forests. (C) 2015 Published by Elsevier B.V
Molecular Transformation of Crude Oil in Confined Pyrolysis System and Its Impact on Migration and Maturity Geochemical Parameters
No full textThe compositions of crude oils can vary significantly during thermal maturation through cracking and aromatization. In this study, an immature high sulfur crude oil was pyrolyzed in a closed gold-tube system with heating rates of 20 degrees C/h and 2 degrees C/h, respectively, to simulate the thermal maturation process of crude oil. The molecular compositions of heteroatom-containing compounds in crude oil were investigated by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) while the impact of thermal maturation on migration and maturity geochemical parameters were investigated by gas chromatography mass spectrometry (GC-MS). Based on the analysis of pyrolysis products, the compositional variations of heteroatom-containing aromatic compounds and the validity of the aromatic geochemical parameters during thermal maturation were investigated. When the equivalent vitrinite reflectance value (Easy %Ro) was greater than ca. 0.85, alkyl chain cracking was the major reaction and led to the producing of a large amount of ca. 1.18) due to further secondary cracking. Polycyclic aromatic compounds (PAHs) gradually became the dominant compounds in pyrolysis products; the carbon number of alkyl chains attached to aromatic core decreased while the aromaticity increased. Simultaneously, polar heteroatomcontaining species became more dealkylated and aromatic with the increasing of maturity. The valid maturity range of geochemical parameters relevant to oil migration and maturity based on heteroatom-containing aromatic compounds were also discussed
RETRACTED ARTICLE: Lentinan protects cardiomyocytes against hypoxia-induced injury by regulation of microRNA-22/Sirt1
No full textWe, the Editors and Publisher of the journal Artificial Cells, Nanomedicine, and Biotechnology, have retracted the following article:Shaohui Zhang & Yongliang Zhao (2019) Lentinan protects cardiomyocytes against hypoxia-induced injury by regulation of microRNA-22/Sirt1. Artificial Cells, Nanomedicine, and Biotechnology, 47:1, 3938–3946, DOI: 10.1080/21691401.2019.1666863Since publication, concerns have been raised about the integrity of the data in the article. When approached for an explanation, the authors have been unable to verify their original data. The authors have agreed to retract the article.We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions.The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’
Transverse spinning of particles in highly focused vector vortex beams
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Transverse spin angular momentum, which appears locally in the structured optical fields, has attracted much attention, owing to its extraordinary properties and potential applications. We show theoretically that, by highly focusing a vector vortex beam with azimuthally varied polarization, it is possible to trap multiple particles simultaneously and manipulate the particles' spin along the azimuthal direction. Both the direction and the magnitude of the spin angular momentum, so the spin torque on the particle, can be varied by changing the state of the input beams. Moreover, the magnitude of the spin torque can be manipulated further by changing the characteristics of the particles. Such results may be exploited in practical optical manipulation, especially for optically induced rotations.</p
Mixed nanomicelles as potential carriers for systemic delivery of Z-GP-Dox, an FAPα-based doxorubicin prodrug: formulation and pharmacokinetic evaluation
No full textYuchen Zhang,1,* Xingwang Zhang,2,* Hongming Liu,2 Shaohui Cai,1 Baojian Wu21Department of Pharmacology, 2Division of Pharmaceutics, College of Pharmacy, Jinan University, Guangzhou, People’s Republic of China*These authors contributed equally to this workAbstract: Z-GP-Dox, the FAPα (fibroblast activation protein-α)-based doxorubicin prodrug, demonstrates excellent tumor targeting effects and a favorable toxicokinetic profile. However, the insoluble nature of Z-GP-Dox becomes a significant barrier to drug administration, particularly when it comes to the clinical stage. Here we developed a nanomicelle system to facilitate the systemic delivery of Z-GP-Dox, and evaluated its disposition in rats following administration of the micelles using a physiologically-based pharmacokinetic model. Z-GP-Dox-loaded mixed nanomicelles (ZGD-MNs) were prepared by dispersion of an ethanol solution of Z-GP-Dox, lecithin, and sodium oleate in water. The obtained ZGD-MNs were 86.6 nm in size with a drug loading of 14.03%. ZGD-MNs were fairly stable in phosphate-buffered saline and simultaneously showed satisfactory physical and chemical stability over a 2-week observation period. Accumulative drug release was more than 56% within 24 hours. Further, the physiologically-based pharmacokinetic rat model consisting of various organs (ie, heart, liver, spleen, lung, kidney, and intestine) was fitted to the experimental data following administration of ZGD-loaded cosolvent (control) or micelles. Derived partition coefficient values revealed that the nanomicelles significantly altered the biodistribution of Z-GP-Dox. Of note, drug distribution to the lung, liver, and spleen was greatly enhanced and the fold change ranged from 2.4 to 33. In conclusion, this is the first report of a mixed micelle system being a viable carrier for delivery of Z-GP-Dox. Also, the pharmacokinetic behavior of Z-GP-Dox was satisfactorily described by the physiologically-based pharmacokinetic model.Keywords: doxorubicin, Z-GP-Dox, micelles, systemic delivery, pharmacokinetics, physiologically-based pharmacokinetic mode
Spinning and orbiting motion of particles in vortex beams with circular or radial polarizations
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Focusing fields of optical vortex (OV) beams with circular or radial polarizations carry both spin angular momentum (SAM) and orbital angular momentum (OAM), and can realize non-axial spinning and orbiting motion of absorptive particles. Using the T-matrix method, we evaluate the optical forces and torques exerted on micro-sized particles induced by the OV beams. Numerical results demonstrate that the particle is trapped on the circle of intensity maxima, and experiences a transverse spin torque along azimuthal direction, a longitudinal spin torque, and an orbital torque, respectively. The direction of spinning motion is not only related to the sign of topological charge of the OV beam, but also to the polarization state. However, the topological charge controls the direction of orbiting motion individually. Optically induced rotations of particles with varying sizes and absorptivity are investigated in OV beams with different topological charges and polarization states. These results may be exploited in practical optical manipulation, especially for optically induced rotations of micro-particles. (C) 2016 Optical Society of America</p
An Inquiry Into the Cultivation of Teachers’ Critical Thinking in Teacher Education and Teacher Professional Development Projects
Full text linkTeacher education and teacher professional development programs often focus on the reinforcement of explicit knowledge, ignoring the improvement of implicit ability, such as critical thinking ability. There should not only be a course titled ‘How to develop critical thinking’, but critical thinking education should be integrated throughout teacher education or development programs. This paper tries to define a teacher’s critical thinking in pedagogical behaviors from the perspective of the role of being a teacher and clarify the connotation of a teacher’s critical thinking ability in his/her pedagogical work, which encompasses a multitude of essential elements, including thinking carefully, determining wisely and reflecting rationally. Corresponding initiatives are incorporated by means of cultivation of the awareness of critical thinking ability, development of critical thinking skills that permeate all aspects of the curriculum and revision of the syllabus and implementation process of training courses through evaluation and feedback
L'influence du droit uniforme international sur le droit chinois des contrats
Full text linkThe thesis consists in a comparative study between, on the one hand, the United-Nations Convention on Contracts for the International Sale of Goods (1980, CISG) and the Unidroit Principles of International Commercial Contracts (1994, 2004, PICC) and, on the other hand, the Unified Contracts Law of the People's Republic of China (1999, UCL). For the purpose of this thesis, importance is attached on the influence exercised by the first two texts, analyzed as example of uniform international law, on the UCL, envisaged as example of Chinese contracts law. The study is done in three aspects, i.e., the legislative aspect, the doctrinal aspect and the practical aspect. With respect to the legislative aspect, the most important conclusion that could be drawn from the analysis is that, for the different stages of contract live, the legislative policies of the UCL are deeply influenced by the uniform international law, particularly by PICC, and at the legislative technical level, this influence is not sufficient, for the formulation of the UCL norms, which are usually less clear, less precise and less complete than uniform international law. The latter conclusion is also valid for the doctrinal aspect. In fact, without denying some positive aspects, the influence exercised by uniform international law on Chinese doctrine is not significant. Firstly, the example which witnesses relatively complete uniform law influence is rare. We can only quote the case of offer and acceptation, about which Chinese scholars unanimously agree to the influence of uniform international law. Secondly, in a number of cases, the penetration of uniform international law to Chinese doctrine appears superficial. Finally, for the cases about which uniform rules were rejected without substitution, Chinese scholars seek rarely solution from uniform international law. A distinction must be operated between the influence of uniform international law (particularly CISG) on Chinese judiciary practice and those on Chinese international commercial arbitration practice. While the first is qualified of negative, the latter is quite positive. In fact, Chinese judges commit usually mistake on the applicability of CISG, while Chinese arbiters do not only exanimate the applicability, but also apply it correctly. Contrary to Chinese judges who render judgment in a very concise style, Chinese arbiters give generally reasoning to their awards. Finally, the number of cases calls also for reflection. Before a small number of judicial decisions (only 19 decisions reported), the arbitration awards become already significant (230 awards). As a conclusion, we can say that the influence exercised by uniform international law on Chinese contracts law is significant with respect to the legislative policies and to international arbitration practice in China, while it is not sufficient to the doctrinal aspect and to the judicial practice. But despite that (fact), the modern and international character of the UCL, as a result of this influence, brings already a better protection to the international commercial contracts concluded between Chinese and foreigner.La thèse consiste en une étude comparative entre, d'une part, la Convention des Nations-Unies du 11 avril 1980 sur les contrats de vente internationale de marchandises (CVIM) et les Principes d'Unidroit relatifs aux contrats de commerce international (Principes d'Unidroit) et, d'autre part, la Loi de la République populaire de Chine du 15 mars 1999 relative aux contrats (LCC). L'accent est mis sur l'influence exercée par les deux premiers textes, en tant qu'exemple du droit uniforme international, sur la LCC, envisagée comme exemple du droit chinois des contrats. L'analyse se fait en trois aspects, à savoir, l'aspect législatif, l'aspect doctrinal et l'aspect pratique. 01 Au niveau législatif La conclusion la plus importante que nous puissions tirer des recherches au niveau de l'influence législative, est que dans toutes les étapes de la vie du contrat, les politiques législatives de la LCC sont fortement influencées par le droit uniforme international, en particulier par les Principes d'Unidroit. Cela est confirmé par de nombreux exemples : les principes généraux posés par les articles 3 à 8 de la LCC, la contravention essentielle servant de condition préalable à la résolution du contrat, les limitations destinées à restreindre le recours trop facile à la résolution, l'effet libératoire en principe ex nunc de la résolution, la restitution dessinée comme une faculté et non comme une obligation et, enfin, le principe de réparation intégrale des dommages-intérêts limités à la prévisibilité
En revanche, au niveau de la technique législative, l'influence du droit uniforme international s'avère encore insuffisante en ce sens que la formulation des règles du droit chinois des contrats est souvent moins précise, moins complète voire défectueuse par rapport à celle du droit uniforme. Les exemples sont très nombreux. On cite notamment la formulation des principes généraux, comme celle de la liberté contractuelle ou celle du principe de bonne foi. On peut aussi constater la réception incomplète de certaines notions : comme la contravention essentielle, la contravention anticipée et le Nachfrist
02 Au niveau doctrinal Sans dénier certains éléments positifs, l'influence du droit uniforme dans la doctrine chinoise, qui est dominée largement par le droit allemand, nous paraît encore insuffisante. Cela est confirmé par plusieurs faits que nous avons établis au cours de nos recherches. 1) Tout d'abord, les exemples qui témoignent d'une influence relativement complète du droit uniforme sont très rares. Le seul exemple consiste dans les règles sur l'offre et l'acceptation, que la doctrine chinoise reconnaît de manière quasi-unanime comme origine le droit uniforme. 2) Ensuite, dans de nombreux exemples, la pénétration du droit uniforme ne semble pas atteindre un degré suffisant. C'est le cas de la notion de contravention essentielle que la plupart des auteurs chinois mentionnent sans procéder à une analyse approfondie. On peut citer aussi la force majeure, l'effet libératoire de la résolution, le système de dommages-intérêts..., hypothèses dans lesquelles les règles de la LCC sont quasi-identiques à celles du droit uniforme, alors que les auteurs chinois font rarement référence au droit uniforme pour les interpréter. 3) Enfin, on note que, devant certains rejets des solutions du droit uniforme qui deviennent des lacunes de la LCC, rares sont les auteurs qui ont recours aux solutions proposées par le droit uniforme. 03 Au niveau pratique Si l'application judiciaire du droit uniforme en Chine est qualifiée de négative, son application arbitrale, en particulier celle de la CVIM, est très positive. 1) Les juges étatiques commettent d'importantes erreurs dans l'applicabilité de la Convention. En revanche, les arbitres chinois examinent non seulement de manière attentive le fondement juridique d'application du droit uniforme, mais en font aussi une application souvent fondée (l'applicabilité). 2) Par rapport aux juges étatiques qui appliquent la Convention souvent de manière ambiguë, l'application arbitrale est généralement claire et correcte (le fond d'application). 3) Contrairement aux jugements chinois qui sont rendus dans un style trop concis, les sentences arbitrales raisonnent souvent de manière bien plus attentive (le raisonnement). 4) Enfin, le nombre de cas d'application de la Convention appelle aussi des réflexions. Face à un petit nombre de décisions judiciaires (19 cas), les sentences arbitrales appliquant la Convention deviennent très abondantes (230 sentences) (la fréquence). 5) En somme, le droit uniforme, en particulier la Convention, a effectivement exercé une forte influence dans la pratique du commerce international en Chine, surtout dans l'arbitrage commercial international. En conclusion, l'influence exercée par le droit uniforme international sur le droit chinois des contrats se fait fortement ressentir surtout dans les politiques législatives de la LCC, sur l'arbitrage du commerce international en Chine, tandis qu'une telle influence reste encore insuffisante en ce qui concerne la technique législative, la doctrine et l'application judiciaire du droit uniforme international. Malgré tout, le caractère moderne et international de la LCC, issue de cette influence, apporte d'ores et déjà une meilleure protection aux contrats conclus entre des Chinois d'une part et des étrangers d'autre part.(Doctorat en droit) (DROI 3) -- UCL, 200
Comparison of Semi-Physical and Empirical Models in the Estimation of Boreal Forest Leaf Area Index and Clumping with Airborne Laser Scanning Data
Full text linkLeaf area index (LAI) is an important forest canopy variable that is related to various biophysical processes of forest ecosystems. Airborne laser scanning (ALS) has shown promise in modeling and mapping LAI using different types of ALS metrics. The most common ways of modeling LAI with ALS data are multivariate empirical models and the semi-physical model shape derived from the Beer–Lambert law of radiation attenuation. We tested the utility of ALS-based empirical and semi-physical models in the estimations of effective LAI (LAIe), canopy clumping index (Omega_E), and clumping-corrected LAI at three boreal forest sites in Finland. In semi-physical models, the all echo penetration index (API) showed consistently the best performance in predicting LAIe. It is, therefore, a robust and potentially the most transferable predictor using this model shape. Empirical models overall yielded slightly better model fits compared to the semi-physical models, yet they are also more prone to overfitting. In addition, empirical models had constantly lower accuracies when predicting LAI than LAIe. We also tested the utility of ALS-based multi-angular canopy gap fraction metrics that were derived from polar transformed ALS point clouds. Images derived from polar transformed point clouds can be analyzed similarly to digital hemispherical photographs (DHPs) to obtain canopy gap fractions. The results showed that polar metrics derived from polar transformed ALS data can provide supporting information to empirical models in the estimation of LAIe, LAI, and especially Omega_E. In particular, a combination of ALS penetration indices and polar metrics yielded positive results in Omega_E estimation.Fil: Zhang, Shaohui. University Of Eastern Finland. Faculty Of Science And Forestry.; FinlandiaFil: Korhonen, Lauri. University Of Eastern Finland. Faculty Of Science And Forestry.; FinlandiaFil: Lang, Mait. University Of Tartu. Faculty Of Science And Technology. Tartu Observatory.; EstoniaFil: Pisek, Jan. University Of Tartu. Faculty Of Science And Technology. Tartu Observatory.; EstoniaFil: Díaz, Gastón Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Korpela, Ilkka. University of Helsinki; FinlandiaFil: Xia, Zhongyu. University Of Eastern Finland. Faculty Of Science And Forestry.; FinlandiaFil: Haapala, Hanna. University Of Eastern Finland. Faculty Of Science And Forestry.; FinlandiaFil: Maltamo, Matti. University Of Eastern Finland. Faculty Of Science And Forestry.; Finlandi
A Comprehensive Survey on Sampling‐Based Image Matting
No full textSampling‐based image matting is currently playing a significant role and showing great further development potentials in image matting. However, the consequent survey articles and detailed classifications are still rare in the field of corresponding research. Furthermore, besides sampling strategies, most of the sampling‐based matting algorithms apply additional operations which actually conceal their real sampling performances. To inspire further improvements and new work, this paper makes a comprehensive survey on sampling‐based matting in the following five aspects: (i) Only the sampling step is initially preserved in the matting process to generate the final alpha results and make comparisons. (ii) Four basic categories including eight detailed classes for sampling‐based matting are presented, which are combined to generate the common sampling‐based matting algorithms. (iii) Each category including two classes is analysed and experimented independently on their advantages and disadvantages. (iv) Additional operations, including sampling weight, settling manner, complement and pre‐ and post‐processing, are sequentially analysed and added into sampling. Besides, the result and effect of each operation are also presented. (v) A pure sampling comparison framework is strongly recommended in future work.Sampling‐based image matting is currently playing a significant role and showing great further development potentials in image matting. However, the consequent survey articles and detailed classifications are still rare in the field of corresponding research. Furthermore, besides sampling strategies, most of the sampling‐based matting algorithms apply additional operations which actually conceal their real sampling performances. To inspire further improvements and new work, this paper makes a comprehensive survey on sampling‐based matting in the following five aspects: (i) Only the sampling step is initially preserved in the matting process to generate the final alpha results and make comparisons. (ii) Four basic categories including eight detailed classes for sampling‐based matting are presented, which are combined to generate the common sampling‐based matting algorithms. (iii) Each category including two classes is analysed and experimented independently on their advantages and disadvantages. (iv) Additional operations, including sampling weight, settling manner, complement and pre‐ and post‐processing, are sequentially analysed and added into sampling. Besides, the result and effect of each operation are also presented. (v) A pure sampling comparison framework is strongly recommended in future work.Computer Graphics ForumArticles368sta
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