Shadow and deflection angle of charged rotating black hole surrounded by perfect fluid dark matter

We analysed the shadow cast by charged rotating black hole (BH) in presence of perfect fluid dark matter (PFDM). We studied the null geodesic equations and obtained the shadow of the charged rotating BH to see the effects of PFDM parameter $\gamma$, charge $Q$ and rotation parameter $a$, and it is noticed that the size as well as the shape of BH shadow is affected due to PFDM parameter, charge and rotation parameter. Thus, it is seen that the presence of dark matter around a BH affects its spacetime. We also investigated the influence of all the parameters (PFDM parameter $\gamma$, BHs charge $Q$ and rotational parameter $a$) on effective potential, energy emission by graphical representation, and compare all the results with the non rotating case in usual general relativity. To this end, we have also explored the effect of PFDM on the deflection angle and the size of Einstein rings.

The Ethics of Religious Studies

This chapter argues that the study of religion lacks an “ethics of religious studies,” by which the author means a theoretical justification of the guild. Focusing on a 1971 report by Claude Welch, Graduate Education in Religion: A Critical Study, it targets Welch’s refusal to provide such a justification and explains its silence by referencing the long shadow cast by Protestant thinking about the dangers of self-justification. It is argued that Welch’s argument erects a firewall between the study of religion and the justification of that study, one that reinforces the commitment to value-neutrality that is described in chapter 1. To explain the field’s preoccupation with methodology, the chapter turns to Stephen Toulmin’s discussion of scientific disciplines and the importance of having a goal as a condition for organizing mature research. It concludes by sketching the outlines of scholarship in religious studies and the distinction between routine work and metadisciplinary work.

Drawing on an architecture of blindness: A critique of the visual privilege operating in architectural representation

<p><b>This thesis exhibits the visual medium of architectural representation destabilized and reinterpreted by locating blindness in architecture. What can blind drawing allow architects to see? </b></p> <p>As a primary medium of architectural representation, drawing is an agency through which architecture is conceptualised, developed and disseminated. Conventionally, drawings are generated and perceived through sight: they are visual projections. Such visual privilege reduces the subject of architectural representations to visible, physical elements of buildings, while invisible, and/or intangible aspects of architectural experience often lack consideration in drawing. The architectural design process can be described as the translation of architecture between the mediums of drawing and building. The context of representation describes this translation as shifting from conceptual to conventional drawing types. While the visual privilege constantly operates in both conceptual and conventional drawing, the differences between their visual languages enable them to describe different aspects of architectural experience. The main difference that this thesis explores is the strictly visual vocabulary of conventional drawing, and the ambiguous capacity of conceptual drawing, enabling it to reference both visual and non-visual aspects of architectural experience. </p> <p>This thesis places conceptual and conventional drawing in parallel, aiming to exaggerate their differences on paper, and what they represent in reality, highlighting where and how architecture risks being weakened during a course of translation. The first half challenges the visual privilege through blind drawing as an alternative mode of conceptual drawing, while the second half identifies invisible aspects of architectural experience that cannot be depicted through conventional drawing. In concluding the research, these differences also evidence opportunities offered by the dual capacity of architectural representation, which simultaneously depicts visible (and physical), and invisible (and intangible) elements. For example, a line as a wall, also defines invisible space either side of said wall – perhaps dotted by the warmth of morning sun and cooler patches of shadow cast by window mullions. This thesis addresses a shift away from the ingrained visual privilege thriving in architectural thought. While drawing remains an inevitably visual medium, the design process must consider both visual and non-visual aspects, equally incorporated by an architectural experience. To exploit the dual capacity of representation, such methods of drawing should encourage architects to draw as though they are blind.</p>

Drawing on an architecture of blindness: A critique of the visual privilege operating in architectural representation

<p><b>This thesis exhibits the visual medium of architectural representation destabilized and reinterpreted by locating blindness in architecture. What can blind drawing allow architects to see? </b></p> <p>As a primary medium of architectural representation, drawing is an agency through which architecture is conceptualised, developed and disseminated. Conventionally, drawings are generated and perceived through sight: they are visual projections. Such visual privilege reduces the subject of architectural representations to visible, physical elements of buildings, while invisible, and/or intangible aspects of architectural experience often lack consideration in drawing. The architectural design process can be described as the translation of architecture between the mediums of drawing and building. The context of representation describes this translation as shifting from conceptual to conventional drawing types. While the visual privilege constantly operates in both conceptual and conventional drawing, the differences between their visual languages enable them to describe different aspects of architectural experience. The main difference that this thesis explores is the strictly visual vocabulary of conventional drawing, and the ambiguous capacity of conceptual drawing, enabling it to reference both visual and non-visual aspects of architectural experience. </p> <p>This thesis places conceptual and conventional drawing in parallel, aiming to exaggerate their differences on paper, and what they represent in reality, highlighting where and how architecture risks being weakened during a course of translation. The first half challenges the visual privilege through blind drawing as an alternative mode of conceptual drawing, while the second half identifies invisible aspects of architectural experience that cannot be depicted through conventional drawing. In concluding the research, these differences also evidence opportunities offered by the dual capacity of architectural representation, which simultaneously depicts visible (and physical), and invisible (and intangible) elements. For example, a line as a wall, also defines invisible space either side of said wall – perhaps dotted by the warmth of morning sun and cooler patches of shadow cast by window mullions. This thesis addresses a shift away from the ingrained visual privilege thriving in architectural thought. While drawing remains an inevitably visual medium, the design process must consider both visual and non-visual aspects, equally incorporated by an architectural experience. To exploit the dual capacity of representation, such methods of drawing should encourage architects to draw as though they are blind.</p>

Shadow cast and quasinormal modes in f(R) gravity model inspired by Yang–Mills field

In this paper, the null geodesic equations are computed in [Formula: see text] space–time dimensions [Y. Younesizadeh, A. A. Ahmad, A. H. Ahmed, F. Younesizadeh, Ann. Phys. 420, 168246 (2020)] by using the concept of symmetries and Hamilton–Jacobi equation and Carter separable method. With these null geodesics in hand, we evaluate the celestial coordinates (x, y) and the radius [Formula: see text] of the BH shadow and represent it graphically. In addition, we have shown that the peak of this energy slowly shifts to lower frequencies and its height decreases with the increase in the YM magnetic charge ([Formula: see text]) values and decrease in the [Formula: see text] parameter ([Formula: see text]) values. In addition, we have analyzed the concept of effective potential barrier by transforming the radial equation of motion into standard Schrodinger form. The most important result derived from this study is that the height of this potential increases with increase in the YM magnetic charge ([Formula: see text]) values. Then, we study the quasinormal modes (QNMs) of these 4D black holes. For this purpose, we use the WKB approximation method upto third-order corrections. We have shown the perturbation’s decay in corresponding diagrams when the YM magnetic charge ([Formula: see text]) values and the [Formula: see text] parameter ([Formula: see text]) values change.

Shadow cast by a rotating and nonlinear magnetic-charged black hole in perfect fluid dark matter

In this paper, we derived an exact solution of the spherically symmetric Hayward black hole surrounded by perfect fluid dark matter (PFDM). By applying the Newman–Janis algorithm, we generalized it to the corresponding rotating black hole. Then, we studied the shadows of rotating Hayward black hole in PFDM. The apparent shape of the shadow depends upon the black hole spin [Formula: see text], the magnetic charge [Formula: see text] and the PFDM intensity parameter [Formula: see text]. The shadow is a perfect circle in the non-rotating case [Formula: see text] and a deformed one in the rotating case [Formula: see text]. For a fixed value of [Formula: see text], the size of the shadow increases with the increasing [Formula: see text], but decreases with the increasing [Formula: see text]. We further investigated the black hole emission rate. We found that the emission rate decreases with the increasing [Formula: see text] (or [Formula: see text]) and the peak of the emission shifts to lower frequency. Finally, we discussed the observational prospects corresponding to the supermassive black hole Sgr A[Formula: see text] at the center of the Milky Way.

Magufuli’s death offers limited reform opening

Significance The former vice-president took office after President John Magufuli died of heart complications following widespread rumours he had contracted COVID-19. Since coming to power in 2015, Magufuli dominated the ruling Chama Cha Mapinduzi (CCM) party and the Tanzanian political scene. Impacts The long shadow cast by Magufuli means the new government is unlikely to reverse his policies quickly. Growing party factionalism will likely exacerbate corruption, eroding some of the gains secured under Magufuli. Civil society groups and political exiles will wait to see how Samia intends to govern before resuming their activities.