199 research outputs found
A Spatial Statistical Analysis on Intra-Country Economy in Chongqing From Inputs Point of View
In order to analyze the region difference and the dynamic changes of intra-country economy in Chongqing since the implementation of coordinating urban and rural development, the paper analyze quantitatively the spatial distribution of economic growth level, capital investment, human capital investment and credit investment in countries of Chongqing by spatial statistical analysis method taking 35 countries of Chongqing as spatial units. Then we compare the spatial clustering of three inputs with it of economic growth level in the county of Chongqing. The results show that there exist positive spatial autocorrelation of economic growth level, capital investment and credit investment except human capital investment between countries; it reflects the significant improvement of inputs on economic growth in country that the spatial clustering state of inputs and economic growth level are similar
An intrinsic nonlinear Ohmic current
It is known that intrinsic currents in magnetic metals often appear in the
direction perpendicular to the external field for linear and nonlinear
responses. Distinct from three kinds of known nonlinear currents, namely, the
Drude contribution, the Berry curvature dipole induced current and the Berry
connection polarization induced current, here we report a intrinsic nonlinear
current with breaking time-reversal symmetry. This new kind of intrinsic
nonlinear current from the nontrivial Berry connection polarizability may
emerge in the longitudinal or transverse direction, and both are dissipative
Ohmic currents. We unveil 66 magnetic point group symmetries that can
accommodate such nonlinear current, and possible candidate materials are
proposed. This theory is also applied to observe the nonlinear current we
proposed in one- and two-dimensional Dirac systems as examples
Phylogeny of Middle-Late Ordovician lituitid cephalopods based on cladistic analysis
Phylogenetic studies are rare in early Palaeozoic cephalopods. Here, we present the first cladistic analysis of the order Lituitida based on published, as well as some new, material. Three clades are recovered within the ingroup of lituitids, Sinoceras, Ancistroceras and Lituites; the former two groups correspond to the family Sinoceratidae, and the latter one to the Lituitidae. The topology shows that the Sinoceratidae represents the basal branch, while the Lituitidae represents a monophyletic, derived clade. Furthermore, we describe new material of four species (three of which are newly defined) in four genera of the order Lituitida from the well-exposed, Middle to Upper Ordovician of Hubei (South China). The described species include Lituites evolutus Fang, Chen & Zhang, Sinoceras complexum Fang sp. nov., Tyrioceras longicameratum Fang sp. nov. and Rhynchorthoceras yizanense Fang sp. nov. Tyrioceras longicameratum from South China is the first reported occurrence of Tyrioceras in China, which has significant palaeogeographical implications.Peer reviewe
Malongitubus: a possible pterobranch hemichordate from the early Cambrian of South China
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Malongitubus kuangshanensis Hu, 2005 from the early Cambrian Chengjiang Lagerstätte of China is redescribed as a pterobranch and provides the best evidence to demonstrate that hemichordates were present as early as Cambrian Stage 3. Interpretation of this taxon as a hemichordate is based on the morphology of the branched colony and the presence of resistant inner threads consistent with the remains of an internal stolon system. The presence of fusellar rings in the colonial tubes cannot be unambiguously proven for Malongitubus, probably due to early decay and later diagenetic replacement of the thin organic material of the tubarium, although weak annulations are still discernible in parts of the tubes. The description of M. kuangshanensis is revised according to new observations of previously reported specimens and recently collected additional new material. Malongitubus appears similar in most features to Dalyia racemata Walcott, 1919 from the Cambrian Stage 5 Burgess Shale, but can be distinguished by the existence of disc-like thickenings at the bases of tubarium branching points in the latter species. Both species occur in rare mass-occurrence layers with preserved fragmentary individuals of different decay stages, with stolon remains preserved as the most durable structures. Benthic pterobranchs may have occurred in some early Cambrian shallow marine communities in dense accumulations and provided firm substrates and shelter for other benthic metazoans as secondary tierers
Mixed Precision Quantization of ConvNets via Differentiable Neural Architecture Search
Recent work in network quantization has substantially reduced the time and
space complexity of neural network inference, enabling their deployment on
embedded and mobile devices with limited computational and memory resources.
However, existing quantization methods often represent all weights and
activations with the same precision (bit-width). In this paper, we explore a
new dimension of the design space: quantizing different layers with different
bit-widths. We formulate this problem as a neural architecture search problem
and propose a novel differentiable neural architecture search (DNAS) framework
to efficiently explore its exponential search space with gradient-based
optimization. Experiments show we surpass the state-of-the-art compression of
ResNet on CIFAR-10 and ImageNet. Our quantized models with 21.1x smaller model
size or 103.9x lower computational cost can still outperform baseline quantized
or even full precision models
Effects of Climate Warming on Net Primary Productivity in China During 1961–2010
The response of ecosystems to different magnitudes of climate warming and corresponding precipitation changes during the last few decades may provide an important reference for predicting the magnitude and trajectory of net primary productivity (NPP) in the future. In this study, a process-based ecosystem model, Carbon Exchange between Vegetation, Soil and Atmosphere (CEVSA), was used to investigate the response of NPP to warming at both national and subregional scales during 1961–2010. The results suggest that a 1.3°C increase in temperature stimulated the positive changing trend in NPP at national scale during the past 50 years. Regardless of the magnitude of temperature increase, warming enhanced the increase in NPP; however, the positive trend of NPP decreased when warming exceeded 2°C. The largest increase in NPP was found in regions where temperature increased by 1–2°C, and this rate of increase also contributed the most to the total increase in NPP in China\u27s terrestrial ecosystems. Decreasing precipitation depressed the positive trend in NPP that was stimulated by warming. In northern China, warming depressed the increasing trend of NPP and warming that was accompanied by decreasing precipitation led to negative changing trends in NPP in large parts of northern China, especially when warming exceeded 2°C. However, warming stimulated the increase in NPP until warming was greater than 2°C, and decreased precipitation helped to increase the NPP in southern China
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