Summary
The Kilian and Murphy (Journal of Applied Econometrics, 2014, 29, 454–478) structural vector autoregressive model has become the workhorse model for the analysis of oil markets. I explore ...various refinements and extensions of this model, including the effects of (1) correcting an error in the measure of global real economic activity, (2) explicitly incorporating narrative sign restrictions into the estimation, (3) relaxing the upper bound on the impact price elasticity of oil supply, (4) evaluating the implied posterior distribution of the structural models, and (5) extending the sample. I demonstrate that the substantive conclusions of Kilian and Murphy (2014) are largely unaffected by these changes.
•There are many alternative indicators of global real economic activity.•New evidence and new insights help understand the differences.•Indices derived from shipping rates and commodity price factors ...are most suitable.•Pros: accurate timing, long monthly series, global coverage, robust to structural change.•Systematic evidence of a global slowdown after 2011 in commodity markets.
It is widely understood that the real price of globally traded commodities is determined by the forces of demand and supply. One of the main determinants of the real price of commodities is shifts in the demand for commodities associated with unexpected fluctuations in global real economic activity. There have been numerous proposals for quantifying global real economic activity. We discuss which criteria a measure of global real activity must satisfy to be useful for modeling industrial commodity prices, we examine which of the many alternative measures in the literature are most suitable for applied work, and we explain why some popular measures are inappropriate for modeling industrial commodity prices. Given these insights, we examine the question of whether there has been a slowdown in global real economic activity between 2011 and 2016 and by how much. Drawing on a range of new evidence, we show that the global commodity price boom of the 2000s appears to have been largely transitory and that the partial recovery after 2016 has been fueled by the strength of advanced economies rather than China. Our analysis has important implications for the design of structural models of commodity markets, for the analysis of the transmission of commodity price shocks to commodity-importing and -exporting economies, and for commodity price forecasting.
The l1 regularization technique has been developed for structural health monitoring and damage detection through employing the sparsity condition of structural damage. The regularization parameter, ...which controls the trade-off between data fidelity and solution size of the regularization problem, exerts a crucial effect on the solution. However, the l1 regularization problem has no closed-form solution, and the regularization parameter is usually selected by experience. This study proposes two strategies of selecting the regularization parameter for the l1-regularized damage detection problem. The first method utilizes the residual and solution norms of the optimization problem and ensures that they are both small. The other method is based on the discrepancy principle, which requires that the variance of the discrepancy between the calculated and measured responses is close to the variance of the measurement noise. The two methods are applied to a cantilever beam and a three-story frame. A range of the regularization parameter, rather than one single value, can be determined. When the regularization parameter in this range is selected, the damage can be accurately identified even for multiple damage scenarios. This range also indicates the sensitivity degree of the damage identification problem to the regularization parameter.
A theoretical model, for dynamic control of double plasmon-induced transparencies in aperture-coupled metal-dielectric-metal (MDM) waveguide-cavity system, is proposed. Based on the theoretical and ...numerical results, the formation and evolution mechanisms of double plasmon-induced transparencies are investigated more accurately compared to previous works. The symmetries, positions and measured full width at half maximum (FWHM) of the double transparent windows, and the transmission phase shift can be tuned freely by structural parameters. Moreover, the slot cavity location relative to aperture affects the phase difference between the left and right slot cavities to aperture center and determines the wavelength of resonance mode in aperture-side-coupled slot cavity, which plays an important role in the appearance or disappearance of transparent windows. In particular, supported by the consistency between the theoretical analysis and simulations, we obtain the threshold of coupling distance between two apertures, at which the abrupt phase shift happens. The detailed analysis may open up the possibility for precise control of light in highly integrated optical circuits.
Dissolved organic matter (DOM) has an important effect on soil fertility, activity of microorganisms and transport of contaminants. In this study, DOM released by the hydrochar and biochar prepared ...under various conditions from pig manure, was assessed using a combination of UV–Visible spectroscopy, fluorescence excitation-emission (EEM) spectrophotometry and 1H-nuclear magnetic resonance (1H NMR). The dissolved organic carbon (DOC) extracted from the hydrochar and biochar ranged from 3.34–11.96% and 0.38–0.48%, respectively, and the highest DOM was released by HCK0.5 (180 °C and 0.5% KOH). The aliphatic compounds were most common in DOM which mainly included three humic acid-like and one protein-like substance. The hydrochar-DOM had a larger molecular weight and lower aromaticity than biochar-DOM, but the effect of temperature on the DOM characteristics of hydrochar and biochar was opposite. The acidic treatment increased the content of functional groups containing oxygen and nitrogen in hydrochar-DOM, and alkaline treatment increased the content of aliphatic compounds. The results obtained are beneficial to select carbonation process and guide the rational application of hydrochar and biochar from pig manure in soil remediation field.
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•The higher concentration of DOM in hydrochar than biochar•The hydrochar-DOM had a larger molecular weight and lower aromaticity.•There are mainly three humic acid-like and one protein-like substance in DOM.•The relative proportion of aliphatic compounds in DOM was the highest.•The dilute alkali treatment increased the content and instability of hydrochar-DOM.
Magnetic topological insulators (TI) provide an important material platform to explore quantum phenomena such as quantized anomalous Hall effect and Majorana modes, etc. Their successful material ...realization is thus essential for our fundamental understanding and potential technical revolutions. By realizing a bulk van der Waals material MnBi
Te
with alternating septuple MnBi
Te
and quintuple Bi
Te
layers, we show that it is ferromagnetic in plane but antiferromagnetic along the c axis with an out-of-plane saturation field of ~0.22 T at 2 K. Our angle-resolved photoemission spectroscopy measurements and first-principles calculations further demonstrate that MnBi
Te
is a Z
antiferromagnetic TI with two types of surface states associated with the MnBi
Te
or Bi
Te
termination, respectively. Additionally, its superlattice nature may make various heterostructures of MnBi
Te
and Bi
Te
layers possible by exfoliation. Therefore, the low saturation field and the superlattice nature of MnBi
Te
make it an ideal system to investigate rich emergent phenomena.
Chemotherapeutic insensitivity remains a major obstacle to treating osteosarcoma effectively. Recently, increasing evidence has suggested that microRNAs (miRNAs) are involved in drug resistance. ...However, the effect of miR-138 on cisplatin chemoresistance in osteosarcoma has not been reported. We used real-time PCR to detect the expression of mature miR-138 in osteosarcoma tissues and cell lines. Cell proliferation, invasion, and migration assays were used to observe changes to the osteosarcoma malignant phenotype. MiR-138 was downregulated in osteosarcoma tissues and cell lines, and miR-138 overexpression negatively regulated osteosarcoma cell proliferation, migration, and invasion. We also verified that EZH2 is a direct target of miR-138. Furthermore, enhancing EZH2 expression reduced the inhibitory effects of miR-138 on osteosarcoma. Proliferation, apoptosis assays and caspase-3 activity assay confirmed that elevated miR-138 expression enhanced osteosarcoma cell chemosensitivity to cisplatin by targeting EZH2. In conclusion, the present study demonstrates that miR-138 acts as a tumor suppressor by enhancing osteosarcoma cell chemosensitivity and supports its potential application for treating osteosarcoma in the future.
A novel 1:1 cocrystal explosive of 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (HNIW) and benzotrifuroxan (BTF) has been prepared. The structure of this cocrystal was characterized by single crystal ...X-ray diffraction (SXRD). Properties of the cocrystal including thermal decomposition and detonation performance were studied. Further, the cocrystal explosive is predicted to display superior detonation power compared to BTF.
The purpose was to analyze the clinical significance of miR-200a in children with initially diagnosed SLE and renal damage. Children with initially diagnosed SLE (n=100) and healthy children (n=50) ...undergoing physical examinations during the same period were recruited. Disease activity of SLE children was determined based on SLEDAI (systemic lupus erythematosus disease activity index), and they were divided to SLEDAI≤9 group and SLEDAI>9 group, respectively. Moreover, SLE children were divided to LN group and non-LN group based on the occurrence of lupus nephritis. Differential level of miR-200a between groups was detected by qRT-PCR. Spearman correlation test was conducted to analyze the influence of miR-200a on SLEDAI and other laboratory indexes of SLE children. Its diagnostic potential in SLE and LN was assessed through depicting ROC curves. MiR-200a level was remarkably lower in SLE children than that of healthy children. Lower level of miR-200a was detected in SLE children with high SLEDAI or accompanied LN. MiR-200a level was negatively correlated to SLEDAI (r=-0.425), ESR (r=-0.284), CRP (r=-0.338), BUN (r=-0.263) and Scr (r=-0.345), while it was positively correlated to C3 (r=0.631), C4 (r=0.524) and ALB (r=0.394) in SLE children. The AUC of miR-200a in diagnosing SLE was 0.8379 (cut-off value=2.225, sensitivity=70%, specificity=70%). Besides, the AUC of miR-200a in diagnosing LN was 0.7619 (cut-off value=2.005, sensitivity=80%, specificity=76%). MiR-200a level has a certain correlation to the disease activity of children with initially diagnosed SLE, which can be utilized as an adjuvant indicator in evaluating SLE severity. Meanwhile, miR-200a has predictive value for SLE-induced renal damage.
We intended to evaluate expression and mechanisms of human microRNA 1270 (hsa-miR-1270) in papillary thyroid cancer (PTC).
In PTC cell lines and human PTC tumors, hsa-miR-1270 expressions were ...evaluated by qRT-PCR. Hsa-miR-1270 was downregulated in TPC1 and K1 cells via lentiviral transduction. Its effects on PTC cancer cell proliferation, migration and in vivo transplantation were assessed, respectively. Potential targeting of hsa-miR-1270 on downstream gene, Suppressor Of Cancer Cell Invasion (SCAI), was assessed. In hsa-miR-1270-downregulated PTC cells, SCAI was further downregulated to examine its associating role in hsa-miR-1270-mediated regulation on cancer cell proliferation and migration.
Hsa-miR-1270 was aberrantly upregulated in PTC cell lines and human PTC tumors. In TPC1 and K1 cells, lentivirus-mediated hsa-miR-1270 downregulation suppressed cancer cell proliferation, migration and in vivo transplantation. Hsa-miR-1270 binds SCAI and inversely regulated SCAI gene expression in PTC cells. SCAI downregulation removed the suppressing effects of hsa-miR-1270 downregulation in human PTC cells.
Hsa-miR-1270 downregulation may suppress human PTC cell development both in vitro and in vivo. The regulatory mechanism of hsa-miR-1270 in PTC may be primarily associated with SCAI.
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