CHINA'S HOG PRODUCTION STRUCTURE AND EFFICIENCY

Over the last 20 years, China's demand for and supply of livestock products has increased dramatically. Although, China's livestock production has changed, with the share of pork production declining, pork production remains the core of the country's livestock industry. China's hog industry is adjusting to capture the benefits of specialization. This paper attempts to capture structural changes in China's hog production, its evolving trends, and economic efficiency. We estimate parametrically the overall efficiency and scale elasticity of 2500 surveyed hog farms in China. Our analysis indicates that the large commercialized farms are the most efficient but the middle size specialized farms with increasing returns to scale production technology are the most profitable.Livestock Production/Industries,

Design and Fabrication of Fiber-Optic Nanoprobes for Optical Sensing

This paper describes the design and fabrication of fiber-optic nanoprobes developed for optical detection in single living cells. It is critical to fabricate probes with well-controlled nanoapertures for optimized spatial resolution and optical transmission. The detection sensitivity of fiber-optic nanoprobe depends mainly on the extremely small excitation volume that is determined by the aperture sizes and penetration depths. We investigate the angle dependence of the aperture in shadow evaporation of the metal coating onto the tip wall. It was found that nanoaperture diameters of approximately 50 nm can be achieved using a 25° tilt angle. On the other hand, the aperture size is sensitive to the subtle change of the metal evaporation angle and could be blocked by irregular metal grains. Through focused ion beam (FIB) milling, optical nanoprobes with well-defined aperture size as small as 200 nm can be obtained. Finally, we illustrate the use of the nanoprobes by detecting a fluorescent species, benzo[a]pyrene tetrol (BPT), in single living cells. A quantitative estimation of the numbers of BPT molecules detected using fiber-optic nanoprobes for BPT solutions shows that the limit of detection was approximately 100 molecules

Simple and Effective Curriculum Pointer-Generator Networks for Reading Comprehension over Long Narratives

This paper tackles the problem of reading comprehension over long narratives where documents easily span over thousands of tokens. We propose a curriculum learning (CL) based Pointer-Generator framework for reading/sampling over large documents, enabling diverse training of the neural model based on the notion of alternating contextual difficulty. This can be interpreted as a form of domain randomization and/or generative pretraining during training. To this end, the usage of the Pointer-Generator softens the requirement of having the answer within the context, enabling us to construct diverse training samples for learning. Additionally, we propose a new Introspective Alignment Layer (IAL), which reasons over decomposed alignments using block-based self-attention. We evaluate our proposed method on the NarrativeQA reading comprehension benchmark, achieving state-of-the-art performance, improving existing baselines by $51\%$ relative improvement on BLEU-4 and $17\%$ relative improvement on Rouge-L. Extensive ablations confirm the effectiveness of our proposed IAL and CL components.Comment: Accepted to ACL 201

GSIS: An efficient and accurate numerical method to obtain the apparent gas permeability of porous media

The apparent gas permeability (AGP) of a porous medium is an important parameter to predict production of unconventional gas. The Klinkenberg correlation, which states that the ratio of the AGP to the intrinsic permeability is approximately a linear function of reciprocal mean gas pressure, is one of the most popular estimations to quantify AGP. However, due to the difficulty in defining the characteristic flow length in complex porous media where the rarefied gas flow is multiscale, the slope in the Klinkenberg correlation varies significantly for different geometries such that a universal expression seems impossible. In this paper, by solving the gas kinetic equation using the general synthetic iterative scheme (GSIS), we compute the AGP in porous media that are represented by Sierpinski fractals and pore body/throat systems. With the abilities of fast convergence to steady-state solution and asymptotic preserving of Navier-Stokes limit, it is shown that GSIS is a promising tool to simulate low-speed rarefied gas flow through complex multiscale geometries. A new definition of the characteristic flow length is proposed as a function of porosity, tortuosity and intrinsic permeability of porous media, which enables to find a unique slope in the Klinkenberg correlation for all the considered geometries. This research also shows that the lattice Boltzmann method using simple wall scaling for the effective shear viscosity is not able to predict the AGP of porous media

Politics of memories: Identity construction in museums

This paper adopts collective memory theory to reveal processes through which heritage tourism stakeholders (re)construct contested national identity. Theoretically sensitised to identity crisis, the study analyses how Hong Kong and Macao heritage managers utilise complex transnational memories to (re)construct an identity aligned with, yet distinct from, that of China. Through a critical discourse analysis of interviews and discursive exhibition and museum texts, the article reveals that museum managers formulate heritage imaginings and a sense of belonging(s) through defining the collective memory for “Self” and “Other”. The article concludes that, by collective memory-building, museum professionals make tangible statements of national identities through legitimating negotiations and resistance in heritage tourism discourse. Implications for heritage tourism studies and museum management are also discussed