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مجمع بيبا السكني
((مجمع بيبا السكني)) رواية تتخذ من موضوع التخفيف من حدة الفقر موضوعا لها، وتركز على \"الأقوياء\" الذين لا يقهرون في تجربة مكافحة الفقر. وتتخذ من مجمع بيبا السكني في إحدى القرى الجبلية الفقيرة في المنطقة السوفيتية المركزية بجيانغشي مسرحا لأحداث الرواية، ومن خلال الماضي والحاضر لأحد المجمعات السكنية وبأسلوب فني تعيد تجسيد معجزة التخفيف من حدة الفقر في تلك المنطقة القديمة بخصائص ومشاعر فريدة. في هذا المجمع السكني الفقير المليء بطابع الهاكا ودفء المشاعر الإنسانية، تستخدم الكاتبة القلم النسائي الدقيق والموهوب والحساس لتنسج للقاريء لوحة فنية لمجموعة من الشخصيات المحبوبة المحترمة، ومن بينهم خه جين هوا وجين تساي فنغ وغيرهم من كوادر مساعدة الفقراء، وشي هاو تساي وشيوي شيو تشن وغيرهم من المستهدفين للتخفيف من حدة الفقر، بالإضافة إلى عم أخرس وعجوز جيوي تسي اللذين يمثلان الجيش الأحمر القديم وأهالى العسكريين.
Book
Born–Infeld black holes in 4D Einstein–Gauss–Bonnet gravity
A novel four-dimensional Einstein-Gauss-Bonnet gravity was formulated by Glavan and Lin (Phys. Rev. Lett. 124:081301, 2020), which is intended to bypass the Lovelock’s theorem and to yield a non-trivial contribution to the four-dimensional gravitational dynamics. However, the validity and consistency of this theory has been called into question recently. We study a static and spherically symmetric black hole charged by a Born–Infeld electric field in the novel four-dimensional Einstein–Gauss–Bonnet gravity. It is found that the black hole solution still suffers the singularity problem, since particles incident from infinity can reach the singularity. It is also demonstrated that the Born-Infeld charged black hole may be superior to the Maxwell charged black hole to be a charged extension of the Schwarzschild-AdS-like black hole in this new gravitational theory. Some basic thermodynamics of the black hole solution is also analyzed. Besides, we regain the black hole solution in the regularized four-dimensional Einstein–Gauss–Bonnet gravity proposed by Lü and Pang (
arXiv:2003.11552
).
Journal Article
Shadow of a charged black hole with scalar hair
Seeking singularity free solutions are important for further understanding black holes in quantum level. Recently, a five-dimensional singularity free black hole/topological star was constructed (Bah and Heidmann in Phys Rev Lett 126:151101, 2021). Through the Kaluza–Klein reduction, an effective four-dimensional static spherically symmetric charged black hole with scalar hair can be obtained. In this paper, we study shadow of this charged black hole with scalar hair in terms of four kinds of observers, i.e., static observers, surrounding observers, freely falling observers, and escaping observers in four-dimensional spacetime. For a spherically symmetric black hole, the shadow is circular for any observer, but the shadow size depends on the motion status of the observer. On the other hand, the effect of plasma is also investigated by a simple model. The radius of the photon sphere depends on the plasma model. Most importantly, we find that the shadow sizes do not monotonically decrease with
r
in some cases.
Journal Article
Charged spherically symmetric and slowly rotating charged black hole solutions in bumblebee gravity
In this paper, we study the scenario in which the matter field is an electromagnetic field nonminimally coupled to the bumblebee vector field. We present exact charged spherically symmetric black hole solutions and slowly rotating charged solutions in bumblebee gravity with and without a cosmological constant. The static spherically symmetric solutions describe the Reissner–Nordström-like black hole and Reissner–Nordström-(anti) de Sitter-like black hole, while the stationary and axially symmetric solutions describe the Kerr–Newman-like black hole and Kerr–Newman–(anti) de Sitter-like black hole. We utilize the Hamilton–Jacobi formalism to study the shadows of the black holes. Additionally, we investigate the effect of the electric charge and Lorentz-violating parameters on the radius of the shadow reference circle and the distortion parameter. We find that the radius of the reference circle decreases with the Lorentz-violating parameter and the charge parameter, while the distortion parameter increases with the Lorentz-violating parameter and the charge parameter.
Journal Article
Building Energy Prediction Models and Related Uncertainties: A Review
Building energy usage has been an important issue in recent decades, and energy prediction models are important tools for analysing this problem. This study provides a comprehensive review of building energy prediction models and uncertainties in the models. First, this paper introduces three types of prediction methods: white-box models, black-box models, and grey-box models. The principles, strengths, shortcomings, and applications of every model are discussed systematically. Second, this paper analyses prediction model uncertainties in terms of human, building, and weather factors. Finally, the research gaps in predicting building energy consumption are summarised in order to guide the optimisation of building energy prediction methods.
Journal Article
The impact of microplastics polystyrene on the microscopic structure of mouse intestine, tight junction genes and gut microbiota
Microplastics, which are tiny plastic particles less than 5 mm in diameter, are widely present in the environment, have become a serious threat to aquatic life and human health, potentially causing ecosystem disorders and health problems. The present study aimed to investigate the effects of microplastics, specifically microplastics-polystyrene (MPs-PS), on the structural integrity, gene expression related to tight junctions, and gut microbiota in mice. A total of 24 Kunming mice aged 30 days were randomly assigned into four groups: control male (CM), control female (CF), PS-exposed male (PSM), and PS-exposed female (PSF)(n = 6). There were significant differences in villus height, width, intestinal surface area, and villus height to crypt depth ratio (V/C) between the PS group and the control group(C) (p <0.05). Gene expression analysis demonstrated the downregulation of Claudin-1 , Claudin-2 , Claudin-15 , and Occludin , in both duodenum and jejunum of the PS group (p < 0.05). Analysis of microbial species using 16S rRNA sequencing indicated decreased diversity in the PSF group, as well as reduced diversity in the PSM group at various taxonomic levels. Beta diversity analysis showed a significant difference in gut microbiota distribution between the PS-exposed and C groups (R2 = 0.113, p<0.01), with this difference being more pronounced among females exposed to MPs-PS. KEGG analysis revealed enrichment of differential microbiota mainly involved in seven signaling pathways, such as nucleotide metabolism(p<0.05). The relative abundance ratio of transcriptional pathways was significantly increased for the PSF group (p<0.01), while excretory system pathways were for PSM group(p<0.05). Overall findings suggest that MPs-PS exhibit a notable sex-dependent impact on mouse gut microbiota, with a stronger effect observed among females; reduced expression of tight junction genes may be associated with dysbiosis, particularly elevated levels of Prevotellaceae .
Journal Article
Thermodynamical topology with multiple defect curves for dyonic AdS black holes
Dyonic black holes with quasitopological electromagnetism exhibit an intriguing phase diagram with two separated first-order coexistence curves. In this paper, we aim to uncover its influence on the black hole thermodynamical topology. At first, we investigate the phase transition and phase diagram of the dyonic black holes. Comparing with previous study that there is no black hole phase transition region for a middle pressure, we find this region can narrow or disappear by fine tuning the coupling parameter. Instead, two first-order phase transitions can be observed. Importantly, we uncover that such novel phase diagram shall lead to a multiple defect curve phenomenon in black hole topology where each dyonic black hole is treated as one defect in the thermodynamical parameter space. By examining the topology, it is shown that there could be one, three, or five black hole states for given pressure and temperature. For each case, the topological number is calculated. Our results show that the topological number always takes value of
+
1
, keeping unchanged even when the multiple defect curves appear. Therefore, our study provides an important ingredient on understanding the black hole thermodynamical topology.
Journal Article
Testing the nature of Gauss–Bonnet gravity by four-dimensional rotating black hole shadow
The recent discovery of the novel four-dimensional static and spherically symmetric Gauss–Bonnet black hole provides a promising bed to test Gauss–Bonnet gravity by using astronomical observations (Glavan et al. in PRL 124:081301, 2020). In this paper, we first obtain the rotating Gauss–Bonnet black hole solution by using the Newman–Janis algorithm and then study the shadow cast by the nonrotating and rotating candidate Gauss–Bonnet black holes. The result indicates that positive metric parameter
α
shrinks the shadow, while negative one enlarges it. Meanwhile, both the distortion and ratio of two diameters of the shadow are found to increase with the metric parameter for certain spin. Comparing with the Kerr black hole, the shadow gets more distorted for
α
and less distorted for negative one. Furthermore, we calculate the angular diameter of the shadow by making use of the observation of M87*. The result indicates that negative metric parameter
α
in (−4.5, 0) is more favored. Since the negative energy appears for negative
α
, our results extends the study of Gauss–Bonnet gravity. We believe further study on the four-dimensional rotating black hole may shed new light on Gauss–Bonnet gravity.
Journal Article
Complexity growth rates for AdS black holes in massive gravity and f(R) gravity
The “complexity = action” duality states that the quantum complexity is equal to the action of the stationary AdS black hole within the Wheeler–DeWitt patch at late time approximation. We compute the action growth rates of the neutral and charged black holes in massive gravity and the neutral, charged and Kerr–Newman black holes in
f
(
R
) gravity to test this conjecture. Besides, we investigate the effects of the massive graviton terms, higher derivative terms and the topology of the black hole horizon on the complexity growth rate.
Journal Article
Equivalence of solutions between the four-dimensional novel and regularized EGB theories in a cylindrically symmetric spacetime
Recently, a novel four-dimensional Einstein–Gauss–Bonnet (EGB) theory was presented to bypass the Lovelock’s theorem and to give nontrivial effects on the four-dimensional local gravity. The main mechanism is to introduce a redefinition
α
→
α
/
(
D
-
4
)
and to take the limit
D
→
4
. However, this theory does not have standard four-dimensional field equations. Some regularization procedures are then proposed to address this problem (
http://arxiv.org/abs/2003.11552
,
http://arxiv.org/abs/2003.12771
,
http://arxiv.org/abs/2004.08362
,
http://arxiv.org/abs/2004.09472
,
http://arxiv.org/abs/2004.10716
). The resultant regularized four-dimensional EGB theory has the same on-shell action as the original theory. Thus it is expected that the novel four-dimensional EGB theory is equivalent to its regularized version. However, the equivalence of these two theories is symmetry-dependent. In this paper, we test the equivalence in a cylindrically symmetric spacetime. The well-defined field equations of the two theories are obtained, with which our follow-up analysis shows that they are equivalent in such spacetime. Cylindrical cosmic strings are then considered as specific examples of the metric. Three sets of solutions are obtained and the corresponding string mass densities are evaluated. The results reveal how the Gauss–Bonnet term in four dimensions contributes to the string geometry in the new theory.
Journal Article