This paper examines spillover effects among six commodity futures markets – gold, silver, West Texas Intermediate crude oil, corn, wheat, and rice – by employing the multivariate DECO-GARCH model and ...the spillover index. Specifically, we investigate the dynamics of return and volatility spillover indices to reveal the intensity and direction of transmission during the recent global financial and European sovereign debt crises. Our empirical results are as follows. First, we estimate a positive equicorrelation between commodity futures market returns and find that it increased sharply during the crises. This effect can persist during periods of economic and financial turmoil, diminishing the benefits of international portfolio diversification for investors. Second, we identify bidirectional return and volatility spillovers across commodity futures markets, and find more pronounced trends in their levels in the post-crisis period. This indicates the strong impact of spillovers during crisis periods. Third, both gold and silver are information transmitters to other commodity futures markets, while the remaining four commodity futures investigated were receivers of spillovers during recent periods of financial stress. Finally, we analyse the optimal portfolio weights and time-varying hedge ratios between metal and other commodities futures markets. Overall, our findings provide new insights into channels of information transmission, which may improve investment decisions and inform portfolio investors' trading strategies.
•We investigate return and volatility spillover effects among six commodity futures.•We examine the intensity and direction of information transmission.•We employ both the multivariate DECO-GARCH model and spillover index.•Spillover effects are particularly intensified during recent financial crises.•We evaluate and compare optimal portfolio weights and time-varying hedge ratios.
Microfluidic technologies have recently been shown to hold significant potential as novel tools for producing micro- and nano-scale structures for a variety of applications in tissue engineering and ...cell biology. Over the last decade, microfluidic spinning has emerged as an advanced method for fabricating fibers with diverse shapes and sizes without the use of complicated devices or facilities. In this critical review, we describe the current development of microfluidic-based spinning techniques for producing micro- and nano-scale fibers based on different solidification methods, platforms, geometries, or biomaterials. We also highlight the emerging applications of fibers as bottom-up scaffolds such as cell encapsulation or guidance for use in tissue engineering research and clinical practice.
Microfluidic-based spinning techniques for producing micro- and nano-scale fibers, and their potential applications to tissue engineering are reviewed.
Insulin, IGF axis, adiponectin, and inflammatory markers are associated with breast cancer. Given that physical activity improves prognosis of breast cancer survivors, we investigated the effects of ...exercise on these markers as potential mediators between physical activity and breast cancer.
PubMed, EMBASE, CENTRAL, CINAHL, and SportDiscus were searched up to December 3, 2015, to identify randomized controlled trials (RCT) that investigated the effect of exercise on insulin, IGF axis, and cytokines in breast cancer survivors. Weighted mean difference (WMD) was calculated using either fixed- or random-effects models on the basis of the heterogeneity of the studies.
A total of 18 studies involving 681 breast cancer survivors were included, and these numbers were reduced for individual biomarker analyses. We found that exercise significantly reduced fasting insulin levels WMD, -3.46 μU/mL; 95% confidence interval (CI), -5.97 to -0.95;
= 0.007. Furthermore, potentially meaningful but statistically nonsignificant changes were observed in insulin resistance (WMD, -0.73; 95% CI, -0.54 to 0.13;
= 0.23), adiponectin (WMD, 1.17 μg/mL; 95% CI, -0.87 to 3.20;
= 0.26), and C-reactive protein (WMD, -1.10 mg/L; 95% CI, -2.39 to 0.20;
= 0.10). Subgroup analyses showed that fasting insulin levels were significantly more impacted in studies in which intervention participants experienced a weight reduction (WMD, -7.10 μU/mL; 95% CI, -10.31 to -3.90;
< 0.001).
Exercise reduces fasting insulin levels in breast cancer survivors. This may be due to exercise-induced reductions in body weight.
Practitioners and clinicians may better help breast cancer prognosis be improved through exercise, anticipating physiological effects on cancer.
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This study empirically investigates the statistical characteristics and predictability of Bitcoin return and volatility. The distribution of Bitcoin returns and volatility display a fat right tail ...and high central parts. Bitcoin does not show the dynamic property of volatility persistence, contrary to stylized facts in financial time series. Also, the autoregressive model using past volatility does not well work in predicting changes in Bitcoin volatility for future periods. Investor sentiment regarding Bitcoin has a significant information value for explaining changes in Bitcoin volatility for future periods. These results suggest that Bitcoin appears to be an investment asset with high volatility and dependence on investor sentiment rather than a monetary asset.
•This study examines the statistical properties and predictability of Bitcoin return and volatility.•Distributional property of Bitcoin shows a fat right tail and high central parts.•Interestingly, dynamic property of Bitcoin does not show the general volatility persistence.•Investor sentiment on Bitcoin has an information effect to predict Bitcoin volatility.•Investor sentiment might play a crucial role in the predictability of Bitcoin price changes.
This paper analyzes the dynamic volatility spillovers and network connectedness between stock index and commodity futures markets using the multivariate DECO-FIGARCH model and the spillover index ...method of Diebold and Yilmaz (2014). We estimate a positive equicorrelation between the index and commodity futures and find the highest level of spillover index during the 2008–2009 global financial crisis and 2010–2012 European sovereign debt crisis. Further, we adopt both static and dynamic spillover approaches to identify the net spillover transmitter or receiver across global futures markets. We also measure the directional spillover and assess the net pairwise spillover across global futures markets. Finally, our network connectedness provides specific information on the net pairwise connectedness and intensity of connectedness in different sub-periods.
•We analyze the dynamic volatility spillovers between global futures markets.•We find the highest level of spillover index during recent financial crises.•FTSE 100 index futures is the largest transmitter of volatility spillover shocks.•The direction and intensity of network connectedness are sensitive to financial and economic events.
Abstract
The lengthy time needed for manual landmarking has delayed the widespread adoption of three-dimensional (3D) cephalometry. We here propose an automatic 3D cephalometric annotation system ...based on multi-stage deep reinforcement learning (DRL) and volume-rendered imaging. This system considers geometrical characteristics of landmarks and simulates the sequential decision process underlying human professional landmarking patterns. It consists mainly of constructing an appropriate two-dimensional cutaway or 3D model view, then implementing single-stage DRL with gradient-based boundary estimation or multi-stage DRL to dictate the 3D coordinates of target landmarks. This system clearly shows sufficient detection accuracy and stability for direct clinical applications, with a low level of detection error and low inter-individual variation (1.96 ± 0.78 mm). Our system, moreover, requires no additional steps of segmentation and 3D mesh-object construction for landmark detection. We believe these system features will enable fast-track cephalometric analysis and planning and expect it to achieve greater accuracy as larger CT datasets become available for training and testing.
Recent advances in flexible and stretchable electronics have led to a surge of electronic skin (e-skin)–based health monitoring platforms. Conventional wireless e-skins rely on rigid integrated ...circuit chips that compromise the overall flexibility and consume considerable power. Chip-less wireless e-skins based on inductor-capacitor resonators are limited to mechanical sensors with low sensitivities. We report a chip-less wireless e-skin based on surface acoustic wave sensors made of freestanding ultrathin single-crystalline piezoelectric gallium nitride membranes. Surface acoustic wave–based e-skin offers highly sensitive, low-power, and long-term sensing of strain, ultraviolet light, and ion concentrations in sweat. We demonstrate weeklong monitoring of pulse. These results present routes to inexpensive and versatile low-power, high-sensitivity platforms for wireless health monitoring devices.
Chip-less electronic skin
Flexible electronic materials, or e-skins, can be limited by the need to include rigid components. A range of techniques have emerged to bypass this problem, including approaches for wireless communication and charging based on silicon, carbon nanotubes, or conducting polymers. Kim
et al
. show that epitaxially grown, single-crystalline gallium nitride films on flexible substrates can be used for chip-less, flexible e-skins. The main advantage is that the material is flexible and breathable, thus providing better comfort. The devices convert electrical energy into surface acoustic waves using a piezoelectric resonator. The resonator is sensitive to changes in strain, mass changes due to the absorption or loss of ions, and ultraviolet light, all of which can be used for different sensing measurements. —MSL
Single-crystalline gallium nitride nanomembranes enable high-sensitivity surface acoustic wave sensors for wireless electronic skin.
Continuously feeding influent wastewater containing diverse bacterial species to a wastewater treatment activated sludge bioreactor may influence the activated sludge bacterial community temporal ...dynamics. To explore this possibility, this study tracked influent wastewater and activated sludge bacterial communities by pyrosequencing 16S rRNA genes from four full-scale wastewater treatment plants over a 9-month period. The activated sludge communities showed significantly higher richness and evenness than the influent wastewater communities. Furthermore, the two communities were different in composition and temporal dynamics. These results demonstrate that the impact of the influent wastewater communities on the activated sludge communities was weak. Nevertheless, 4.3–9.3% of the operational taxonomic units (OTUs) detected in the activated sludge were shared with the influent wastewater, implying contribution from influent wastewater communities to some extent. However, the relative OTU abundance of the influent wastewater was not maintained in the activated sludge communities (i.e., weak neutral assembly). In addition, the variability of the communities of the shared OTUs was moderately correlated with abiotic factors imposed to the bioreactors. Taken together, temporal dynamics of activated sludge communities appear to be predominantly explained by species sorting processes in response to influent wastewater communities.
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•The temporal variation of influent and bioreactor bacterial communities was evaluated.•The two communities differed in terms of diversity and composition.•Small portion of bioreactor community was shared with influent community.•The influent relative species abundance was not maintained in the bioreactor.•Species sorting processes explained a majority of the community temporal dynamics.
Heterotypic functional materials with compositional and topographical properties that vary spatiotemporally on the micro- or nanoscale are common in nature. However, fabricating such complex ...materials in the laboratory remains challenging. Here we describe a method to continuously create microfibres with tunable morphological, structural and chemical features using a microfluidic system consisting of a digital, programmable flow control that mimics the silk-spinning process of spiders. With this method we fabricated hydrogel microfibres coded with varying chemical composition and topography along the fibre, including gas micro-bubbles as well as nanoporous spindle-knots and joints that enabled directional water collection. We also explored the potential use of the coded microfibres for tissue engineering applications by creating multifunctional microfibres with a spatially controlled co-culture of encapsulated cells.
The purpose of this study is to develop a comprehensive understanding of young consumers' attitudes, perceptions and behavioural intentions towards the consumption of environmentally sustainable ...textile and apparel products. A total of 701 responses were collected from students attending large universities in the US, South Korea and China. An extended model of planned behaviour was developed and tested based on structural equation modeling approach. The results indicate that consumers' product knowledge, perceived consumer effectiveness and perceived personal relevance significantly affect young consumers' attitudes, subjective norms and perceived behavioural control, thereby affecting purchase intentions for environmentally sustainable textiles and apparel. The research findings will benefit both environmental and economic enhancement efforts among policymakers, educators and industry professionals, enabling them to formulate strategies to ensure better communication with consumers to promote desirable consumption behaviour.
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