Despite rapid advances in modern medical technology and significant improvements in survival rates of many cancers, pancreatic cancer is still a highly lethal gastrointestinal cancer with a low ...5-year survival rate and difficulty in early detection. At present, the incidence and mortality of pancreatic cancer are increasing year by year worldwide, no matter in the United States, Europe, Japan, or China. Globally, the incidence of pancreatic cancer is projected to increase to 18.6 per 100000 in 2050, with the average annual growth of 1.1%, meaning that pancreatic cancer will pose a significant public health burden. Due to the special anatomical location of the pancreas, the development of pancreatic cancer is usually diagnosed at a late stage with obvious clinical symptoms. Therefore, a comprehensive understanding of the risk factors for pancreatic cancer is of great clinical significance for effective prevention of pancreatic cancer. In this paper, the epidemiological characteristics, developmental trends, and risk factors of pancreatic cancer are reviewed and analyzed in detail.
The effects of a paritcle's spin and electric charge on its angular momentum, energy and radius on the innermost stable circular orbit are investigated based on the particle's equations of motion in ...a background of the Kerr–Newmann spacetime. It is found that the particle's angular momentum and energy have monotonous relationships with not only its spin but also its charge; it is also discovered that the spinning particle's radius may change non-monotonously with its charge. Hence, our result remarkably indicates that particles owning identical spin but different charge may degenerate into a same last stable circular orbit.
The energy extraction of the collisional Penrose process has been investigated in recent years. Previous researchers mainly concentrated on the case of nonspin massive or massless particles, and they ...discovered that when the collision occurs near the horizon of extremal rotating black holes, the arbitrary large efficiency can be achieved with the particle’s angular momentum below the critical value as L1<2. In this paper, the energy extraction of spinning massive particles is calculated via the super Penrose process. We obtain the dependence of the impact factor and the turning points on the particle’s spin s. The super Penrose process can occur only when s≤1 and J1<2, where J1 is the spinning particle’s angular momentum. It is found that the efficiency of the energy extraction is monotonously increasing with the particle’s spin s increasing for s<1, and it can become arbitrarily high when the collision occurs close to the horizon. We compare the maximum extracted energy of spinning particles with that of the nonspin case and find a significant increase of the extracted energy. When s→1, the maximum extracted energy can be orders of magnitude larger than that of the nonspin case. For the astrophysical black holes, the large efficiency is also obtained. Naturally, when the particle’s spin s≪1, we can degenerate the result back to the nonspin case.
To understand the effect of third order Lovelock gravity,
P
–
V
criticality of topological AdS black holes in Lovelock–Born–Infeld gravity is investigated. The thermodynamics is further explored with ...some more extensions and in some more detail than the previous literature. A detailed analysis of the limit case
β
→
∞
is performed for the seven-dimensional black holes. It is shown that, for the spherical topology,
P
–
V
criticality exists for both the uncharged and the charged cases. Our results demonstrate again that the charge is not the indispensable condition of
P
–
V
criticality. It may be attributed to the effect of higher derivative terms of the curvature because similar phenomenon was also found for Gauss–Bonnet black holes. For
k
=
0
, there would be no
P
–
V
criticality. Interesting findings occur in the case
k
=
-
1
, in which positive solutions of critical points are found for both the uncharged and the charged cases. However, the
P
–
v
diagram is quite strange. To check whether these findings are physical, we give the analysis on the non-negative definiteness condition of the entropy. It is shown that, for any nontrivial value of
α
, the entropy is always positive for any specific volume
v
. Since no
P
–
V
criticality exists for
k
=
-
1
in Einstein gravity and Gauss–Bonnet gravity, we can relate our findings with the peculiar property of third order Lovelock gravity. The entropy in third order Lovelock gravity consists of extra terms which are absent in the Gauss–Bonnet black holes, which makes the critical points satisfy the constraint of non-negative definiteness condition of the entropy. We also check the Gibbs free energy graph and “swallow tail” behavior can be observed. Moreover, the effect of nonlinear electrodynamics is also included in our research.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Many Hamiltonian problems in the solar system are separable into two analytically solvable parts, and thus serve as a great chance to develop and apply explicit symplectic integrators based ...on operator splitting and composing. However, such constructions are not in general available for curved spacetimes in general relativity and modified theories of gravity because these curved spacetimes correspond to nonseparable Hamiltonians without the two-part splits. Recently, several black hole spacetimes such as the Schwarzschild black hole were found to allow for the construction of explicit symplectic integrators, since their corresponding Hamiltonians are separable into more than two explicitly integrable pieces. Although some other curved spacetimes including the Kerr black hole do not have such multipart splits, their corresponding appropriate time-transformation Hamiltonians do. In fact, the key problem in obtaining symplectic analytically integrable decomposition algorithms is how to split these Hamiltonians or time-transformation Hamiltonians. Considering this idea, we develop explicit symplectic schemes in curved spacetimes. We introduce a class of spacetimes whose Hamiltonians are directly split into several explicitly integrable terms. For example, the Hamiltonian of a rotating black ring has a 13-part split. We also present two sets of spacetimes whose appropriate time-transformation Hamiltonians have the desirable splits. For instance, an eight-part split exists in a time-transformed Hamiltonian of a Kerr–Newman solution with a disformal parameter. In this way, the proposed symplectic splitting methods can be used widely for long-term integrations of orbits in most curved spacetimes we know of.
f(R) Black Holes as Heat Engines Zhang, Ming; Liu, Wen-Biao
International journal of theoretical physics,
12/2016, Letnik:
55, Številka:
12
Journal Article
Recenzirano
With the cosmological constant considered as a thermodynamic variable in the extended phase space, it is natural to study the thermodynamic cycles of the black hole, which is conjectured to be ...performed using renormalization group flow. We first investigate the thermodynamic cycles of a 4-dimensional asymptotically AdS
f
(
R
) black hole. Then we study the thermodynamic cycles of higher dimensional asymptotically AdS
f
(
R
) black holes. It is found that when Δ
V
≪ Δ
P
, the efficiency of isobar-isochore cycles running between high temperature
T
H
and low temperature
T
C
will increase to its maximum value, which is exactly the Carnot cycles’ efficiency both in 4-dimensional and in higher dimensional cases. We speculate that this property is universal for AdS black holes, if there is no phase transition in the thermodynamic cycle. This result may deepen our understanding of the thermodynamics of the AdS black holes.
The collisional Penrose process of charged spinning particles (charged tops) near the black hole/white hole horizon (black hole and white hole horizon) for the metric of an extreme Kerr-Newman black ...hole is studied. We have explicitly written the equation of motion together with the energy gain of the collisional process for the massive particles. We have also investigated the effects of spin and charge hold by the particles as well as that of the angular momentum and charge possessed by the black hole/white hole on the energy extraction.
In this Letter, the nature of phase transition at the critical point of P-V criticality in the extended phase space of RN-AdS black holes has been investigated. By treating the cosmological constant ...and its conjugate quantity as thermodynamic pressure and volume respectively, we introduce the original expressions of Ehrenfest equations directly into the black hole research instead of utilizing the analogy of Ehrenfest equations. We carry out an analytical check of Ehrenfest equations and prove that both Ehrenfest equations are satisfied. So the black hole undergoes a second order phase transition at the critical point. This result is consistent with the nature of liquid–gas phase transition at the critical point, hence deepening the understanding of the analogy of charged AdS black holes and liquid–gas systems.
The radius of the circular orbit for the timelike or lightlike test particle in a background of general spherically symmetric spacetime is viewed as a characterized quantity for the thermodynamic ...phase transition of the corresponding black hole. We generally show that the phase transition information of a black hole can be reflected by its surrounding particle’s circular orbit.
Generating chromosome-level, haplotype-resolved assemblies of heterozygous genomes remains challenging. To address this, we developed gamete binning, a method based on single-cell sequencing of ...haploid gametes enabling separation of the whole-genome sequencing reads into haplotype-specific reads sets. After assembling the reads of each haplotype, the contigs are scaffolded to chromosome level using a genetic map derived from the gametes. We assemble the two genomes of a diploid apricot tree based on whole-genome sequencing of 445 individual pollen grains. The two haplotype assemblies (N50: 25.5 and 25.8 Mb) feature a haplotyping precision of greater than 99% and are accurately scaffolded to chromosome-level.
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