1,246 research outputs found
World Trade Flows: 1962-2000
We document a set of bilateral trade data by commodity for 1962-2000, which is available from www.nber.org/data (International Trade Data, NBER-UN world trade data). Users must agree not to resell or distribute the data for 1984-2000. The data are organized by the 4-digit Standard International Trade Classification, revision 2, with country codes similar to the United Nations classification. This dataset updates the Statistics Canada World Trade Database as described in Feenstra, Lipsey, and Bowen (1997), which was available for years 1970-1992. In that database, Statistics Canada had revised the United Nations trade data, mostly derived from the export side, to fit the Canadian trade classification and in some cases to add data not available from the export reports. In contrast, in the new NBER-UN dataset we give primacy to the trade flows reported by the importing country, whenever they are available, assuming that these are more accurate than reports by the exporters. If the importer report is not available for a country-pair, however, then the corresponding exporter report is used instead. Corrections and additions are made to the United Nations data for trade flows to and from the United States, exports from Hong Kong and China, and imports into many other countries.
Parameter Selection and Uncertainty Measurement for Variable Precision Probabilistic Rough Set
In this paper, we consider the problem of parameter selection and uncertainty measurement for a variable precision probabilistic rough set. Firstly, within the framework of the variable precision probabilistic rough set model, the relative discernibility of a variable precision rough set in probabilistic approximation space is discussed, and the conditions that make precision parameters α discernible in a variable precision probabilistic rough set are put forward. Concurrently, we consider the lack of predictability of precision parameters in a variable precision probabilistic rough set, and we propose a systematic threshold selection method based on relative discernibility of sets, using the concept of relative discernibility in probabilistic approximation space. Furthermore, a numerical example is applied to test the validity of the proposed method in this paper. Secondly, we discuss the problem of uncertainty measurement for the variable precision probabilistic rough set. The concept of classical fuzzy entropy is introduced into probabilistic approximation space, and the uncertain information that comes from approximation space and the approximated objects is fully considered. Then, an axiomatic approach is established for uncertainty measurement in a variable precision probabilistic rough set, and several related interesting properties are also discussed. Thirdly, we study the attribute reduction for the variable precision probabilistic rough set. The definition of reduction and its characteristic theorems are given for the variable precision probabilistic rough set. The main contribution of this paper is twofold. One is to propose a method of parameter selection for a variable precision probabilistic rough set. Another is to present a new approach to measurement uncertainty and the method of attribute reduction for a variable precision probabilistic rough set
Enhancing lysosome biogenesis attenuates BNIP3-induced cardiomyocyte death
Hypoxia-inducible pro-death protein BNIP3 (BCL-2/adenovirus E1B 19-kDa interacting protein 3), provokes mitochondrial permeabilization causing cardiomyocyte death in ischemia-reperfusion injury. Inhibition of autophagy accelerates BNIP3-induced cell death, by preventing removal of damaged mitochondria. We tested the hypothesis that stimulating autophagy will attenuate BNIP3-induced cardiomyocyte death. Neonatal rat cardiac myocytes (NRCMs) were adenovirally transduced with BNIP3 (or LacZ as control; at multiplicity of infection = 100); and autophagy was stimulated with rapamycin (100 nM). Cell death was assessed at 48 h. BNIP3 expression increased autophagosome abundance 8-fold and caused a 3.6-fold increase in cardiomyocyte death as compared with control. Rapamycin treatment of BNIP3-expressing cells led to further increase in autophagosome number without affecting cell death. BNIP3 expression led to accumulation of autophagosome-bound LC3-II and p62, and an increase in autophagosomes, but not autolysosomes (assessed with dual fluorescent mCherry-GFP-LC3 expression). BNIP3, but not the transmembrane deletion variant, interacted with LC3 and colocalized with mitochondria and lysosomes. However, BNIP3 did not target to lysosomes by subcellular fractionation, provoke lysosome permeabilization or alter lysosome pH. Rather, BNIP3-induced autophagy caused a decline in lysosome numbers with decreased expression of the lysosomal protein LAMP-1, indicating lysosome consumption and consequent autophagosome accumulation. Forced expression of transcription factor EB (TFEB) in BNIP3-expressing cells increased lysosome numbers, decreased autophagosomes and increased autolysosomes, prevented p62 accumulation, removed depolarized mitochondria and attenuated BNIP3-induced death. We conclude that BNIP3 expression induced autophagosome accumulation with lysosome consumption in cardiomyocytes. Forced expression of TFEB, a lysosomal biogenesis factor, restored autophagosome processing and attenuated BNIP3-induced cell death
Modeling soil water movement and irrigation management strategies in jujube (Ziziphus jujuba) orchard using HYDRUS-1D
In Xinjiang, an arid region located in the north-western China, water use for irrigation of predominantly jujube (Ziziphus jujuba Mill.) is high whereas water use efficiency is low. Due to that, how to increase irrigation efficiency is highly concerned by the local agricultural authorities. To quantify the irrigation water deep leakage and soil water balance, water application, crop growth, and soil water dynamics were studied on a sandy loam, sandy, and clay field in the years 2010 and 2011. Research shows that the soil water model HYDRUS-1D can be used as a tool to simulate and quantify improved management strategies and update irrigation standards in this region. The parameters sensitivity analysis result showed that soil water bottom flux was sensitive to θs and Ks in soil layers. The simulation results indicated that soil water leakage was influenced by soil texture, irrigation quota and irrigation frequency, and so on. In addition, soil water leakage was very serious under the traditional surface irrigation during jujube growth period. Soil water leakage mainly occurred in growth from mid-June to mid-August, which is the key period for jujube tree demand water, resulting in severe soil water leakage. Therefore, for improving the efficiency of irrigation water use and reducing the deep soil water leakage, it is not suitable to adopt surface irrigation in the study areas. Several different scenarios have been generated to better understand the effect of irrigation management on soil water leakage by HYDRUS-1D model in the study areas. The drip irrigation can reduce soil water leakage. Consequently, it should be recommend adopting drip irrigation technology, which would not only save water but also improve the efficiency of water use in the study areas
- …