Covariant anomaly and Hawking radiation from the modified black hole in the rainbow gravity theory

Recently, Banerjee and Kulkarni (R. Banerjee, S. Kulkarni, arXiv:0707.2449 [hep-th]) suggested that it is conceptually clean and economical to use only the covariant anomaly to derive Hawking radiation from a black hole. Based upon this simplified formalism, we apply the covariant anomaly cancellation method to investigate Hawking radiation from a modified Schwarzschild black hole in the theory of rainbow gravity. Hawking temperature of the gravity's rainbow black hole is derived from the energy-momentum flux by requiring it to cancel the covariant gravitational anomaly at the horizon. We stress that this temperature is exactly the same as that calculated by the method of cancelling the consistent anomaly.Comment: 5 page

Anomaly analysis of Hawking radiation from Kaluza-Klein black hole with squashed horizon

Considering gravitational and gauge anomalies at the horizon, a new method that to derive Hawking radiations from black holes has been developed by Wilczek et al. In this paper, we apply this method to non-rotating and rotating Kaluza-Klein black holes with squashed horizon, respectively. For the rotating case, we found that, after the dimensional reduction, an effective U(1) gauge field is generated by an angular isometry. The results show that the gauge current and energy-momentum tensor fluxes are exactly equivalent to Hawking radiation from the event horizon.Comment: 15 pages, no figures, the improved version, accepted by Eur. Phys. J.

Viscoelastic adhesive interfacial model and experimental characterization for interfacial parameters

In this paper, a three-parameter interfacial model based on Needleman's cohesive theory is presented to characterize the viscoelastic mechanical properties of adhesive structures. For most adhesive structures, the mechanical behavior of adhesive interface layer can be simulated by the proposed adhesive interfacial model. To evaluate effectively the materials parameters of the adhesive layer an improved experiment-based identification method is proposed including four major steps: (1) video-recorded experimental measurement, (2) numerical simulation based on the time-dependent adhesive interfacial model, (3) genetic algorithm, and (4) independent experiment verification. Using the proposed experiment-based identification method, the viscoelastic interfacial mechanical parameters of metal adhesive structures and rubber adhesive structures under tension or shear loading are determined, respectively. Based on the identified parameters, the numerical computational results are in good agreement with the independent experimental measurement results. It seems that the proposed adhesive interfacial model is effective to characterize the mechanical properties of the adhesive layer and the improved experiment-based identification method is promising in solving parameter characterization problems of complex adhesive structures

Tectonic significance of Cretasceous granitoids along the southeast coast of continental China

We present the results of our study on 16 Cretaceous granitoid plutons along the south‐east coast of continental China. The zircon U–Pb ages and the bulk‐rock Rb–Sr isochron age (R2 = 0.935) indicate that the granitoids represent the last episode of magmatism (119–92 Ma) associated with the paleo‐Pacific Plate subduction beneath continental China. These granitoids show large compositional variation that is to a first‐order consistent with varying extents of magma evolution, which is best expressed by a large SiO2/MgO range and correlated trends of SiO2/MgO with the abundances and ratios of major and trace elements. The correlated Nd (εNd(t) = −6.1 to −1.2) and Hf (εHf(t) = −4.7 to +3.4) isotopic variation reflects parental magma compositional differences as a result of varying sources and processes. The Nd–Hf isotope data indicate that these granitoids were produced by mature continental crust melting with significant mantle input (~20–60%). Rhyolite‐MELTS modelling shows that relative to the less evolved (i.e., low SiO2/MgO) granitoid plutons, the progressively more evolved (i.e., varying larger SiO2/MgO) plutons can be explained by varying extents (~24% to 67%) of fractional crystallization. The origin of the magmas parental to the granitoids is best explained by a two‐stage process: (a) subducting slab dehydration‐induced mantle wedge melting for basaltic magmas and (b) ascent and underplating/intrusion of the basaltic magmas caused the mature crustal melting for the granitoid magmas. The systematic northward decrease in εNd(t) and εHf(t) suggests progressively more enriched crustal material towards the north, but it may very well indicate northward crustal thickening, permitting a greater extent of crustal assimilation

The petrogenesis and tectonic significance of the Early Cretaceous intraplate granites in eastern China: The Laoshan granite as an example

The Laoshan granite is an example of the widespread intraplate granitoids of early Cretaceous age in eastern continental China. The petrogenesis of these granitoids remains in dispute and we choose the Laoshan granite as the representative case to study these granitoids. Zircons from the Laoshan granite give a crystallization age of ~120 Ma, which is consistent with the emplacement age of ~ 126 Ma given by the bulk-rock Rb-Sr isochron. Representative samples from the granite show a large range of major element compositional variation (e.g., SiO2/MgO = 64 to 1937), reflecting a varying degree of fractional crystallization of plagioclase, alkali feldspar, amphibole, biotite and accessory phases as observed. The samples are enriched in light rare earth elements, Rb, Th and U, but depleted in Ba and Sr with negative Eu anomalies. The high 87Sr/86Sr (0.7083 to 1.2265) is largely caused by variably high Rb/Sr (~ 0.31 to 91 with an average of ~ 13) due to feldspar fractionation. The low ƐNd(t) (−13.8 to −19.5), εHf(t) (−14.6 to −24.4), and (206Pb/204Pb)i (16.244 to 17.304) are consistent with significant contributions of the lower continental crust to magmas parental to the Laoshan granite. The origin of the parental magmas is best understood as resulting from anatexis of the lower crust (~20% - 25% partial melting of the mafic granulite) triggered by and mixed with the underplating and intruding basaltic magmas. The basaltic magmas were likely derived from melting of the thinning lithosphere being transformed into the asthenosphere as the result of “basal hydration weakening” with the water ultimately coming from dehydration of the stagnant paleo-Pacific slab in the mantle transition zone

Simple and cost-effective methods for precise analysis of trace element abundances in geological materials with ICP-MS

Inductively coupled plasma mass spectrometry (ICP-MS) is the most commonly used technique to determine the abundances of trace elements in a wide range of geological materials. However, incomplete sample digestion, isobaric interferences and instrumental drift remain obvious problems that must be overcome in order to obtain precise and accurate results. For this reason, we have done many experiments and developed a set of simple, cost-effective and practical methods widely applicable for precise and rapid determination of trace element abundances in geological materials using ICP-MS. Commonly used high-pressure digestion technique is indeed effective in decomposing refractory phases, but this inevitably produces fluoride complexes that create new problems. We demonstrate that the fluoride complexes formed during high-pressure digestion can be readily re-dissolved using high-pressure vessel at 190 °C for only 2 h for 50 mg sample. In the case of isobaric interferences, although oxide (e.g., MO+/M+) and hydroxide (e.g., MOH+/M+) productivity is variable between runs, the (MO+/M+)/(CeO+/Ce+) and (MOH+/M+)/(CeO+/Ce+) ratios remain constant, making isobaric interference correction for all other elements of interest straightforward, for which we provide an easy-to-use off-line procedure. We also show that mass-time-intensity drift curve is smooth as recognized previously, for which the correction can be readily done by analyzing a quality-control (QC) solution and using off-line Excel VBA procedure without internal standards. With these methods, we can produce data in reasonable agreement with recommended values of international rock reference standards with a relative error of 60% of time (e.g., 60 h)

Compensatory Mutations of Rifampin Resistance Are Associated with Transmission of Multidrug-Resistant Mycobacterium tuberculosis Beijing Genotype Strains in China.

&lt;p&gt;Mycobacterium tuberculosis can acquire resistance to rifampin (RIF) through mutations in the rpoB gene. This is usually accompanied by a fitness cost, which, however, can be mitigated by secondary mutations in the rpoA or rpoC gene. This study aimed to identify rpoA and rpoC mutations in clinical M. tuberculosis isolates in northern China in order to clarify their role in the transmission of drug-resistant tuberculosis (TB). The study collection included 332 RIF-resistant and 178 RIF-susceptible isolates. The majority of isolates belonged to the Beijing genotype (95.3%, 486/510 isolates), and no mutation was found in rpoA or rpoC of the non-Beijing genotype strains. Among the Beijing genotype strains, 27.8% (89/320) of RIF-resistant isolates harbored nonsynonymous mutations in the rpoA (n = 6) or rpoC (n = 83) gene. The proportion of rpoC mutations was significantly higher in new cases (P = 0.023) and in strains with the rpoB S531L mutation (P &lt; 0.001). In addition, multidrug-resistant (MDR) strains with rpoC mutations were significantly associated with 24-locus mycobacterial interspersed repetitive-unit-variable-number tandem-repeat clustering (P = 0.016). In summary, we believe that these findings indirectly suggest an epistatic interaction of particular mutations related to RIF resistance and strain fitness and, consequently, the role of such mutations in the spread of MDR M. tuberculosis strains.&lt;/p&gt;</p