2,601 research outputs found
Growth and Regional Inequality in China During the Reform Era
Chinese city-level data indicate that differences in growth rates are far more severe than indicated in previous studies which typically use data at higher levels of aggregation. We estimate growth equations using city-level data and find that the policy of awarding a special economic zone status enhances growth substantially, increasing annual growth rates by 5.5 percentage points. Annual growth rates of open coastal cities are, on average, 3 percentage points higher. Our qualitative results on the role of policy and the effects of FDI are similar to those of earlier studies that have employed provincial-level data; but, quantitatively, our results are substantially different. We also provide evidence of an indirect role of policy in the growth process through its ability to attract growth-enhancing foreign direct investment.http://deepblue.lib.umich.edu/bitstream/2027.42/39946/2/wp561.pd
Growth and Regional Inequality in China During the Reform Era
Chinese city-level data indicate that differences in growth rates are far more severe than indicated in previous studies which typically use data at higher levels of aggregation. We estimate growth equations using city-level data and find that the policy of awarding a special economic zone status enhances growth substantially, increasing annual growth rates by 5.5 percentage points. Annual growth rates of open coastal cities are, on average, 3 percentage points higher. Our qualitative results on the role of policy and the effects of FDI are similar to those of earlier studies that have employed provincial-level data; but, quantitatively, our results are substantially different. We also provide evidence of an indirect role of policy in the growth process through its ability to attract growth-enhancing foreign direct investment.growth, regional inequality, China
Content-based Music Similarity with Triplet Networks
We explore the feasibility of using triplet neural networks to embed songs
based on content-based music similarity. Our network is trained using triplets
of songs such that two songs by the same artist are embedded closer to one
another than to a third song by a different artist. We compare two models that
are trained using different ways of picking this third song: at random vs.
based on shared genre labels. Our experiments are conducted using songs from
the Free Music Archive and use standard audio features. The initial results
show that shallow Siamese networks can be used to embed music for a simple
artist retrieval task
Unified Embedding: Battle-Tested Feature Representations for Web-Scale ML Systems
Learning high-quality feature embeddings efficiently and effectively is
critical for the performance of web-scale machine learning systems. A typical
model ingests hundreds of features with vocabularies on the order of millions
to billions of tokens. The standard approach is to represent each feature value
as a d-dimensional embedding, introducing hundreds of billions of parameters
for extremely high-cardinality features. This bottleneck has led to substantial
progress in alternative embedding algorithms. Many of these methods, however,
make the assumption that each feature uses an independent embedding table. This
work introduces a simple yet highly effective framework, Feature Multiplexing,
where one single representation space is used across many different categorical
features. Our theoretical and empirical analysis reveals that multiplexed
embeddings can be decomposed into components from each constituent feature,
allowing models to distinguish between features. We show that multiplexed
representations lead to Pareto-optimal parameter-accuracy tradeoffs for three
public benchmark datasets. Further, we propose a highly practical approach
called Unified Embedding with three major benefits: simplified feature
configuration, strong adaptation to dynamic data distributions, and
compatibility with modern hardware. Unified embedding gives significant
improvements in offline and online metrics compared to highly competitive
baselines across five web-scale search, ads, and recommender systems, where it
serves billions of users across the world in industry-leading products.Comment: NeurIPS'23 Spotligh
ReâOs isotope geochronology of the Shangbao pyriteâflourite deposit in southeastern Hunan, South China: Evidence for multiple mineralization events and the role of crustâmantle interaction in polymetallic deposits
In South China, both crustal reworking and crustâmantle interaction were important geological processes during the Paleozoic and Mesozoic eras. However, the relationships between these two processes and metal mineralization are still unknown. Here we report rhenium and osmium isotopic data for pyrite grains from a pyrite deposit associated with a granite intrusion in the Shangbao area, southeastern Hunan Province (South China). Two pyrite samples, both containing many euhedral pyrite grains, were collected from the same locality, but the samples yield distinct ages. Six euhedral pyrite grains from one sample yield an isochronal age of 279 ± 12 Ma, with an initial 187Os/188Os ratio of 0.39 ± 0.71, and Re and Os concentrations of 0.12â63.5 ppb and 2.14â185 ppt, respectively. This Early Permian age is in good agreement with the age of the strata that host the pyrite deposit. Five euhedral pyrite grains from the other sample yield an isochronal age of 75.2 ± 4.3 Ma, with an initial 187Os/188Os ratio of 0.141 ± 0.030 and Re and Os concentrations of 0.15â0.43 ppb and 1.0â39.9 ppt, respectively. If one pyrite grain with the highest 187Re/188Os and 187Os/188Os ratios is excluded, other four pyrite grains give an isochronal age of 85 ± 13 Ma. The Late Cretaceous age (75â85 Ma) is consistent with the zircon UâPb age of the Shangbao granites (80.1 ± 0.3 Ma) to within uncertainties. Considering also the relatively lower radiogenic initial 187Os/188Os ratio of this sample, we suggest that the later stage pyrite ore was probably formed through crystallization from the magmatic hydrothermal fluids. Combined with other geological and associated magmatic data, we propose a skarn-related fluidâore interaction process to explain the second stage of metallogenesis in the Shangbao pyrite deposit. The Early Permian pyrite ore was deposited in a brine basin with evaporites during the Early Permian. Later magmatic hydrothermal fluids originating from the Shangbao granites, which included mantle components, interacted with the strata and the Early Permian pyrite ore during the Late Cretaceous and precipitated a later stage pyrite ore. During the Late Mesozoic, the roll-back of subducted Paleo-Pacific plate caused lithospheric extension in South China, triggering the upwelling and partial melting of the asthenosphere. The resulting underplating of mantle-derived magmas provided a vast amount of heat and materials for the formation of the granites and polymetallic deposits in South China. Given that the multiple mineralization events were spatially and temporally associated with the PaleozoicâMesozoic magmatism, the ReâOs isotopic dating of euhedral pyrite grains has been shown to be a viable method for unveiling the evolutionary history of ore-deposits. Skarn development caused by granite and mafic dike emplacement resulting from crustâmantle interaction explains the occurrence of two mineralization episodes at the same locality
VolcanoFinder:Genomic scans for adaptive introgression
Recent research shows that introgression between closely-related species is an important source of adaptive alleles for a wide range of taxa. Typically, detection of adaptive introgression from genomic data relies on comparative analyses that require sequence data from both the recipient and the donor species. However, in many cases, the donor is unknown or the data is not currently available. Here, we introduce a genome-scan method-VolcanoFinder-to detect recent events of adaptive introgression using polymorphism data from the recipient species only. VolcanoFinder detects adaptive introgression sweeps from the pattern of excess intermediate-frequency polymorphism they produce in the flanking region of the genome, a pattern which appears as a volcano-shape in pairwise genetic diversity. Using coalescent theory, we derive analytical predictions for these patterns. Based on these results, we develop a composite-likelihood test to detect signatures of adaptive introgression relative to the genomic background. Simulation results show that VolcanoFinder has high statistical power to detect these signatures, even for older sweeps and for soft sweeps initiated by multiple migrant haplotypes. Finally, we implement VolcanoFinder to detect archaic introgression in European and sub-Saharan African human populations, and uncovered interesting candidates in both populations, such as TSHR in Europeans and TCHH-RPTN in Africans. We discuss their biological implications and provide guidelines for identifying and circumventing artifactual signals during empirical applications of VolcanoFinder
Biomechanical determination of distal level for fusions across the cervicothoracic junction
Study DesignâIn vitro testing. ObjectiveâTo determine whether long cervical and cervicothoracic fusions increase the intradiscal pressure at the adjacent caudal disk and to determine which thoracic end vertebra causes the least increase in the adjacent-level intradiscal pressure. MethodsâA bending moment was applied to six cadaveric cervicothoracic spine specimens with intact rib cages. Intradiscal pressures were recorded from C7âT1 to T9â10 before and after simulated fusion by anterior cervical plating and posterior thoracic pedicle screw constructs. The changes in the intradiscal pressure from baseline were calculated and compared. ResultsâNo significant differences where found when the changes of the juxtafusion intradiscal pressure at each level were compared for the flexion, extension, and left and right bending simulations. However, combining the pressures for all directions of bending at each level demonstrated a decrease in the pressures at the T2âT3 level. Exploratory analysis comparing changes in the pressure at T2âT3 to other levels showed a significant decrease in the pressures at this level (pâ=â0.005). ConclusionsâBased on the combined intradiscal pressures alone it may be advantageous to end long constructs spanning the cervicothoracic junction at the T2 level if there are no other mitigating factors
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