579 research outputs found
Dynamics, space, and regional inequality in provincial China: a case study of Guangdong province
pre-printThis paper investigates the regional inequality in one of the most developed provinces in China, Guangdong, from 1979 to 2009 and follows the multi-scale and multi-mechanism framework. We have found a new round of intensifying inequality in Guangdong since the early 2000s, which is attributed to the widening gap between the core region of the Pearl River Delta (PRD) and the rest of the province (periphery) and between the urban and rural areas. The authors also apply a distribution dynamics approach and spatial Markov chains to identify the spatial-temporal dynamics of regional disparities in Guangdong. The results show that there has been a progressive bias towards a poverty trap in the province and the effect of self-reinforcing agglomeration is evident. Using a multilevel model, the study further unfolds that the regional inequality in Guangdong is sensitive to the core-periphery hierarchy of multi-mechanisms and reveals the relative influence of decentralization, marketization and globalization. We argue that the policies towards inequality-reducing in Guangdong have been constrained by the geographical barriers and the effect of self-reinforcing agglomeration in the PRD, while marketization has potential to mediate the uneven development driven by the spatial concentration of foreign investment
PREDICTING PRODUCT RETURN RATE WITH “TWEETS”
This study classifies posts into four distinct topics and uses their sentiment values to predict product return rate at e-commerce websites. The results reveal that the sentiments of posts related to e-commerce company news (i.e., objective posts) are negatively related to product return rate. On the contrary, the sentiments of social network posts related to product use, purchase and service experiences (i.e., subjective posts) are positively related to product return rate at a focal e-commerce website. The paper contributes to product return research as well as social network prediction research. Practitioners may use the method to predict product return rates using social network posts
Why Are People Addicted to SNS? Understanding the Role of SNS Characteristics in the Formation of SNS Addiction
Research has shown that many people use social networking sites (SNS) excessively, which may lead to various negative consequences. With the aim of reducing SNS addition, this study investigates the role of SNS characteristics in the formation of SNS addiction. By applying incentive sensitization theory in the context of SNS addiction, we suggest that the compulsive motivation for using an SNS is developed by pleasurable and rewarding SNS use experiences. Social network characteristics and communication characteristics, which determine the rewards that users obtain from SNS use, moderate the relationship between habitual SNS use and SNS addiction. We develop novel behavioral measures of habitual SNS use and SNS addiction based on SNS activity logs and empirically test the research model using a large and unique dataset. Besides contributing to the theoretical development of SNS addiction, the results of this study offer practical options to help prevent SNS addiction. Moreover, the measures of SNS addiction enable the automated monitoring of user behavior on SNS, which could be useful for detecting potential SNS addicts
Warfarin-related nephropathy occurs in patients with and without chronic kidney disease and is associated with an increased mortality rate
An acute increase in the international normalized ratio (INR; a comparison of prothrombin time to monitor the effects of warfarin) over 3 in patients with chronic kidney disease (CKD) is often associated with an unexplained acute increase in serum creatinine (SC) and an accelerated progression of CKD. Kidney biopsy in a subset of these patients showed obstruction of the renal tubule by red blood cell casts, and this appears to be the dominant mechanism of the acute kidney injury. We termed this warfarin-related nephropathy (WRN), and previously reported cases of WRN only in patients with CKD. We now assess whether this occurs in patients without CKD, its risk factors, and consequences. In 15,258 patients who initiated warfarin therapy during a 5-year period, 4006 had an INR over 3 and SC measured at the same time; however, the large data set precluded individual patient clinical assessment. A presumptive diagnosis of WRN was made if the SC increased by over 0.3mg/dl within 1 week after the INR exceeded 3 with no record of hemorrhage. WRN occurred in 20.5% of the entire cohort, 33.0% of the CKD cohort, and 16.5% of the no-CKD cohort. Other risk factors included age, diabetes mellitus, hypertension, and cardiovascular disease. The 1-year mortality was 31.1% with compared with 18.9% without WRN, an increased risk of 65%. Thus, WRN may be a common complication of warfarin therapy in high-risk patients and CKD doubles this risk. The mechanisms of these risks are unclear
Experimental evidence on the Altshuler-Aronov-Spivak interference of the topological surface states in the exfoliated Bi2Te3 nanoflakes
Here we demonstrate the Altshuler-Aronov-Spivak (AAS) interference of the
topological surface states on the exfoliated Bi2Te3 microflakes by a flux
period of h/2e in their magnetoresistance oscillations and its weak field
character. Both the osillations with the period of h/e and h/2e are observed.
The h/2e-period AAS oscillation gradually dominates with increasing the sample
widths and the temperatures. This reveals the transition of the Dirac Fermions'
transport to the diffusive regime.Comment: version 3;Applied Physics Letters in pres
A cryogen-free dilution refrigerator based Josephson qubit measurement system
This is the published version, also available here: http://dx.doi.org/10.1063/1.3698001.We develop a small-signal measurement system on cryogen-free dilution refrigerator which is suitable for superconductingqubit studies. Cryogen-free refrigerators have several advantages such as less manpower for system operation and large sample space for experiment, but concern remains about whether the noise introduced by the coldhead can be made sufficiently low. In this work, we demonstrate some effective approaches of acoustic isolation to reduce the noise impact. The electronic circuit that includes the current, voltage, and microwave lines for qubit coherent state measurement is described. For the current and voltage lines designed to have a low pass of dc-100 kHz, we show that the measurements of Josephson junction's switching current distribution with a width down to 1 nA, and quantum coherent Rabi oscillation and Ramsey interference of the superconductingqubit can be successfully performed
Coherent Anti-Stokes Raman Holography for Chemically Selective Single-Shot Nonscanning 3D Imaging
The von Hippel-Lindau Tumor Suppressor Protein Promotes c-Cbl-Independent Poly-Ubiquitylation and Degradation of the Activated EGFR
Somatic mutations or reduced expression of the von Hippel-Lindau (VHL) tumor suppressor occurs in the majority of the clear cell renal cell carcinoma (ccRCC) and is a causal factor for the pathogenesis of ccRCC. pVHL was reported to suppress the oncogenic activity of Epidermal Growth Factor Receptor (EGFR) by reducing the expression of the EGFR agonist TGF-α and by reducing the translation efficiency of EGFR itself. Furthermore, it was reported that pVHL down-regulates activated EGFR by promoting efficient lysosomal degradation of the receptor. These modes of negative regulation of EGFR by pVHL were dependent on Hypoxia Inducible Factor (HIF). In this study, we report that HIF was not the only factor stabilizing the activated EGFR in VHL-deficient ccRCC cells. Down-regulation of endogenous HIF in these cells had little effect on the turnover rates of the activated EGFR. Furthermore, neither pretreatment with lysomomal inhibitors pretreatment nor down-regulation of c-Cbl, a major E3 ubiquitin ligase that targets the activated EGFR for lysosomal degradation, significantly increased the stabilities of EGFR in VHL-expressing ccRCC cells. In contrast, pretreatment with proteasomal inhibitors extended EGFR lifetime and led to similar EGFR half-lives in VHL-expressing and VHL-deficient ccRCC cells. Down-regulation of c-Cbl in VHL-deficient ccRCC cells revealed that the c-Cbl and pVHL collaborated to down-regulate the activated EGFR. Finally, we found that pVHL promoted the poly-ubiquitylation of the activated EGFR, and this function was c-Cbl-independent. Thus these results indicate that pVHL limits EGFR signaling by promoting c-Cbl-independent poly-ubiquitylation of the activated receptor, which likely results in its degradation by proteasome
Lithium, an anti-psychotic drug, greatly enhances the generation of induced pluripotent stem cells
Somatic cells can be reprogrammed into induced pluripotent stem cells (iPSCs) by defined factors. The low efficiency of reprogramming and genomic integration of oncogenes and viral vectors limited the potential application of iPSCs. Here we report that Lithium (Li), a drug used to treat mood disorders, greatly enhances iPSC generation from both mouse embryonic fibroblast and human umbilical vein endothelial cells. Li facilitates iPSC generation with one (Oct4) or two factors (OS or OK). The effect of Li on promoting reprogramming only partially depends on its major target GSK3β. Unlike other GSK3β inhibitors, Li not only increases the expression of Nanog, but also enhances the transcriptional activity of Nanog. We also found that Li exerts its effect by promoting epigenetic modifications via downregulation of LSD1, a H3K4-specific histone demethylase. Knocking down LSD1 partially mimics Li's effect in enhancing reprogramming. Our results not only provide a straightforward method to improve the iPSC generation efficiency, but also identified a histone demethylase as a critical modulator for somatic cell reprogramming
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