142 research outputs found
Riemann Surfaces of genus g with an automorphism of order p prime and p>g
The present work completes the classification of the compact Riemann surfaces
of genus g with an analytic automorphism of order p (prime number) and p > g.
More precisely, we construct a parameteriza- tion space for them, we compute
their groups of uniformization and we compute their full automorphism groups.
Also, we give affine equations for special cases and some implications on the
components of the singular locus of the moduli space of smooth curves of genus
g.Comment: 28 pages, 5 figure
A series of coverings of the regular n-gon
We define an infinite series of translation coverings of Veech's double-n-gon
for odd n greater or equal to 5 which share the same Veech group. Additionally
we give an infinite series of translation coverings with constant Veech group
of a regular n-gon for even n greater or equal to 8. These families give rise
to explicit examples of infinite translation surfaces with lattice Veech group.Comment: A missing case in step 1 in the proof of Thm. 1 b was added. (To
appear in Geometriae Dedicata.
A Tonnetz Model for pentachords
This article deals with the construction of surfaces that are suitable for
representing pentachords or 5-pitch segments that are in the same class.
It is a generalization of the well known \"Ottingen-Riemann torus for triads of
neo-Riemannian theories. Two pentachords are near if they differ by a
particular set of contextual inversions and the whole contextual group of
inversions produces a Tiling (Tessellation) by pentagons on the surfaces. A
description of the surfaces as coverings of a particular Tiling is given in the
twelve-tone enharmonic scale case.Comment: 27 pages, 12 figure
Bullets over ballots: Islamist groups, the state and electoral violence in Egypt and Morocco
This article is concerned with state-sponsored electoral violence in liberalized autocracies. The first section of the paper identifies a number of variables that can help explain the decision calculus of authoritarian incumbents to deploy force against strong electoral challengers. The second section then examines these propositions with reference to Egypt and Morocco. Drawing on recent parliamentary elections in both countries the article questions why, despite facing the challenge of political Islam, the two regimes differed so markedly in their willingness to manipulate the polls by recourse to violence. Whilst the Egyptian authorities decided to abrogate all pretence of peaceful elections in favour of violent repression against the Muslim Brotherhood candidates and sympathizers, no such tactics were deployed by the ruling elite in Morocco. We suggest that three principal factors influenced the regimes' response to this electoral challenge: (1) the centrality of the elected institution to authoritarian survival; (2) the availability of alternative electioneering tools; and (3) the anticipated response of the international community. The article concludes by suggesting that in order to understand better when and how states deploy violence in elections, we need to focus on a more complex set of factors rather than simply on the electoral potency of key opposition challengers or the authoritarian nature of the state
Neither participation nor revolution: the strategy of the Moroccan Jamiat al-Adl wal-Ihsan
Scholars and students of Islamist movements are divided over the issue of Islamists' commitment to democracy and a number of studies have attempted to discover the true nature of Islamist parties. This paper rejects this approach and argues that the behaviour of Islamist parties can be better understood through an analysis of the constraints and opportunities that their surrounding environment provides. Specifically, the paper aims at explaining the choice of the Moroccan Jamiat al-Adl wal-Ihsan neither to participate in institutional politics nor to undertake violent actions to transform the regime. This is done through an examination of its relations with the other political actors. The paper argues that Jamiat al-Adl wal-Ihsan's behaviour is as much the product of rational thinking as it is of ideology and provides evidence to support this claim. Such findings are important not only in the Moroccan context, but contribute to a growing literature claiming that Islamist movements should be treated as rational political actors operating under 'environmental' constraints and opportunities
Complement C3 Inhibitor Pegcetacoplan for Geographic Atrophy Secondary to Age-Related Macular Degeneration : A Randomized Phase 2 Trial
Copyright © 2019 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.Peer reviewedPublisher PD
Egyptian Satirical Graphics on Social Media after the Arab Spring
This paper investigates Egyptian digital forms of satirical graphics mostly published on Social Media by cartoonists and amateurs after the Arab Spring. These include: webcomics memes, and Graphic Interchange Format (GIF). The paper will focus on two Facebook pages as a case study: Asa7be Sarcasm Society and Islam Gawish's Elwarka/The Paper. With this aim in mind, I will show how these forms of political satire incorporate, cinema, theatre, religion, western elements and pan-Arabism to express a political view in a creative manner to appeal to a more diverse and broad audience. The first part of the paper provides a brief discussion of Arabic/Egyptian satire with specific reference to political cartoons and Egyptian youth activism on social media (specifically Facebook). It will also introduce the concept of satirical graphics and some of its concrete applications. The second part describes the methodology and provides an analysis of the case study
Purely (Non-)Strongly Real Beauville Groups
We discuss Beauville groups whose corresponding Beauville surfaces
are either always strongly real or never strongly real producing several
infinite families of examples
Is vulnerability to climate change gendered? And how? Insights from Egypt
Most climate change literature tends to downplay the gendered nature of vulnerability. At best, gender is discussed in terms of the male-female binary, seen as opposing forces rather than in varying relations of interdependency. Such construction can result in the adoption of maladaptive culturally unfit gender-blind policy and interventions. In Egypt, which is highly vulnerable to climate change, gender analysis of vulnerability is almost non-existent. This paper addresses this important research gap by asking and drawing on a rural Egyptian context âHow do the gendered relational aspects of menâs and womenâs livelihoods in the household and community influence vulnerability to climate change?â. To answer this question, I draw on gender analysis of social relations, framed within an understanding of sustainable livelihoods. During 16 months of fieldwork, I used multiple ethnographic methods to collect data from two culturally and ethnically diverse low-income villages in Egypt. My main argument is that experiences of climate change are closely intertwined with gender and wider social relations in the household and community. These are shaped by local gendered ideologies and cultures that are embedded in conjugal relations, kinship and relationship to the environment, as compared across the two villages. In this paper, I strongly argue that vulnerability to climate change is highly gendered and therefore gender analysis should be at the heart of climate change discourses, policy and interventions
25th RCOphth Congress, President's Session paper:25 years of progress in medical retina
The quarter century since the foundation of the Royal College of Ophthalmologists has coincided with immense change in the subspecialty of medical retina, which has moved from being the province of a few dedicated enthusiasts to being an integral, core part of ophthalmology in every eye department. In age-related macular degeneration, there has been a move away from targeted, destructive laser therapy, dependent on fluorescein angiography to intravitreal injection therapy of anti-growth factor agents, largely guided by optical coherence tomography. As a result of these changes, ophthalmologists have witnessed a marked improvement in visual outcomes for their patients with wet age-related macular degeneration (AMD), while at the same time developing and enacting entirely novel ways of delivering care. In the field of diabetic retinopathy, this period also saw advances in laser technology and a move away from highly destructive laser photocoagulation treatment to gentler retinal laser treatments. The introduction of intravitreal therapies, both steroids and anti-growth factor agents, has further advanced the treatment of diabetic macular oedema. This era has also seen in the United Kingdom the introduction of a coordinated national diabetic retinopathy screening programme, which offers an increasing hope that the burden of blindness from diabetic eye disease can be lessened. Exciting future advances in retinal imaging, genetics, and pharmacology will allow us to further improve outcomes for our patients and for ophthalmologists specialising in medical retina, the future looks very exciting but increasingly busy
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