45 research outputs found
Some finite quotients of the mapping class group of a surface
No full textLet
S
S
be a smooth, oriented, compact surface of genus
p
⩾
2
p \geqslant 2
, and
Mod
p
{\operatorname {Mod} _p}
its Teichmüller modular group (or mapping class group). Let
T
1
(
S
)
{T_1}(S)
denote the unit tangent bundle, and let
n
n
be an integer dividing
2
p
−
2
2p - 2
.
Mod
p
{\operatorname {Mod} _p}
acts on the finite set
Φ
n
{\Phi _n}
, the elements of which are certain homomorphisms from
H
1
(
T
1
(
S
)
,
Z
n
)
{H_1}({T_1}(S),{{\mathbf {Z}}_n})
to
Z
n
{{\mathbf {Z}}_n}
. In previous work of the author, these homomorphisms arose as the topological description of the
n
n
th roots of the canonical bundle of the universal Teichmüller curve; however, a topological approach is taken here. The subgroups of
G
p
,
n
{G_{p,n}}
which leave all elements of
Φ
n
{\Phi _n}
fixed are subgroups of finite index in
Mod
p
{\operatorname {Mod} _p}
. Let
Q
n
=
Mod
p
/
G
p
,
n
{Q_n} = {\operatorname {Mod} _p}/{G_{p,n}}
. The elements of
Q
n
{Q_n}
are characterized algebraically.
Q
n
{Q_n}
is an extension of
(
2
Z
n
)
2
p
{(2{{\mathbf {Z}}_n})^{2p}}
by the symplectic group
Sp(p,
Z
n
)
{\text {Sp(p,}}{{\mathbf {Z}}_n})
(and in the case of
n
odd
,
Q
n
n \operatorname {odd}, {Q_n}
is a semidirect product).</p
Third order optical nonlinearity of graphene
No full textThis article was published in the New Journal of Physics, 2014 (16). Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.We perform a perturbative calculation of the third order optical conductivities of doped graphene, using approximations valid around the Dirac points and neglecting effects due to scattering and electron–electron interactions. In this limit analytic formulas can be constructed for the conductivities. We discuss in detail the results for third harmonic generation, the Kerr effect and two-photon carrier injection, parametric frequency conversion, and two-color coherent current injection. We find a complicated dependence on the chemical potential and photon energies. The linear dispersion causes resonances over a wide range of photon energies, and it is possible to obtain large optical nonlinearities by tuning the chemical potential.This work has been supported by the EU-FET grant GRAPHENICS (618086), by FWOVlaanderen which provides funding through the FWO project G.A002.13N and the Postdoctoraal Onderzoeker grant for N Vermeulen, by the Natural Sciences and Engineering Research Council of Canada, by VUB-Methusalem, VUB-OZR, and IAP-BELSPO under grant IAP P7-35
Master planned communities and the re-formation of cities for health and wellbeing
No full textMaster planned estates are a common feature of modern cities. This paper explores residents’ social practices to reveal connections between spatial and social features, daily routines and health and wellbeing.
AbstractMaster planned communities (MPCs) are designed to give residents a ‘complete living experience’ including access to educational facilities, shopping centres and parks. Although MPCs aspire to be suburban utopias much research focuses on identifying negative outcomes to reinforce notions that dreams of utopian futures are rarely realised. However, as a dynamic form of city re-formation, MPCs create an opportunity to ‘get it right’ by putting into practice lessons learnt from the past and principles of best practice planning. Selandra Rise is an MPC in Melbourne, Australia that has been designed to maximise the health and wellbeing of residents. Key elements incorporate access to nature, open space for physical activity, diverse housing, access to education, public transport, a local town centre and a focus on generating employment.
This paper presents the details of a study designed to measure the role of built, natural, social and economic environments in the health and wellbeing of residents, taking account of the key design features listed. Using a social practice approach rather than taking an individual behavioural stance, the research focuses on households as a unit of study to reveal the connection between spatial and social features, daily routines and health and wellbeing. The paper presents the methods, outlines findings to date, and reflects on potential policy implications for creating neighbourhoods and cities to improve social and physical health.
Presented at the International Making Cities Livable Conference –20-24 May, 2012, Portland, Oregon US
Cheshire Children's Fund learning mentor service: An evaluation
No full textThis report describes a learning mentor service based in a number of Chester primary schools and assesses whether the service is benefiting users, meeting Children's Fund objectives, and how the service is performing.Commissioned and funded by Cheshire Children's Fund
A full vectorial mapping of nanophotonic light fields
No full textLight is a union of electric and magnetic fields, and nowhere is the complex relationship between these fields more evident than in the near fields of nanophotonic structures. There, complicated electric and magnetic fields varying over subwavelength scales are generally present, which results in photonic phenomena such as extraordinary optical momentum, superchiral fields, and a complex spatial evolution of optical singularities. An understanding of such phenomena requires nanoscale measurements of the complete optical field vector. Although the sensitivity of near-field scanning optical microscopy to the complete electromagnetic field was recently demonstrated, a separation of different components required a priori knowledge of the sample. Here, we introduce a robust algorithm that can disentangle all six electric and magnetic field components from a single near-field measurement without any numerical modeling of the structure. As examples, we unravel the fields of two prototypical nanophotonic structures: a photonic crystal waveguide and a plasmonic nanowire. These results pave the way for new studies of complex photonic phenomena at the nanoscale and for the design of structures that optimize their optical behavior.QN/Quantum Nanoscienc
Statistics for Community Governance: The Yawuru Indigenous Population Survey, Western Australia
No full textThis article presents a case study of an exercise in Aboriginal community governance in Australia. It sets out the background events that led the Yawuru Native Title Holders Aboriginal Corporation in the town of Broome on Australia’s northwest coast to secure information for its own needs as an act of self-determination and essential governance, and it presents some of the key findings from that exercise. As the Indigenous rights agenda shifts from the pursuit of restitution to the management and implementation of benefits, those with proprietary rights are finding it increasingly necessary to build internal capacity for post-native title governance and community planning, including in the area of information retrieval and application. As an incorporated land-holding group, the Yawuru people of Broome are amongst the first in Australia to move in this area of information gathering, certainly in terms of the degree of local control, participation, and conceptual thinking around the logistics and rationale for such an exercise. An innovative addition has been the incorporation of survey output data into a Geographic Information System to provide for spatial analysis and a decision support mechanism for local community planning. In launching and administering the "Knowing our Community" household survey in Broome, the Yawuru have set a precedent in the acquisition and application of demographic information for internal planning and community development in the post-native title determination era
Enhanced Characterization of Membrane Protein Complexes by Ultraviolet Photodissociation Mass Spectrometry
No full textDevelopment of
chemical chaperones to solubilize membrane protein
complexes in aqueous solutions has allowed for gas-phase analysis
of their native-like assemblies, including rapid evaluation of stability
and interacting partners. Characterization of protein primary sequence,
however, has thus far been limited. Ultraviolet photodissociation
(UVPD) generates a multitude of sequence ions for the E. coli ammonia channel (AmtB), provides improved localization of a possible
post-translational modification of aquaporin Z (AqpZ), and surpasses
previous reports of sequence coverage for mechanosensitive channel
of large conductance (MscL). Variations in UVPD sequence ion abundance
have been shown to correspond to structural changes induced upon some
perturbation. Preliminary results are reported here for elucidating
increased rigidity or flexibility of MscL when bound to various phospholipids
Livros ilustrados: textos e imagens
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Literatura, Florianópolis, 2014.O objetivo desta dissertação é investigar o lugar que ocupam as ilustrações na produção atual de livros para crianças e jovens no que diz respeito ao seu papel narrativo dentro da obra e, principalmente, no que oferecem ao olhar sensível como possibilidade de leitura da imagem. Para tanto, analisarei as relações entre texto escrito e ilustração em livros editados no Brasil na atualidade, principalmente a partir dos anos 2000, atendo-me às ilustrações enquanto busco esclarecer questões poéticas, adensamentos e complexidades. A fim de refletir alguns aspectos referentes à literatura aliada às ilustrações, essa análise se dá a partir de três perspectivas diferentes. Primeiramente, considero a ilustração como elemento que amplia o texto e que se adapta a distintos contextos culturais, correntes estéticas ou ideologias, de acordo com a visão do artista que a executa. Em segundo lugar, aprofundo a noção de que a ilustração faz mais do que representar visualmente o texto escrito, considerando-a como elemento que transforma o texto original quando organizado nas páginas do livro. Para concluir, proponho que, além de ampliar e/ou transformar o texto, a ilustração pode ser vista como elemento polissêmico, gerador de imagens críticas que tocam a realidade sem, no entanto, se predispor a retratá-la de forma única, fechada e estanque. Quando falamos em imagem, tendemos a pensar em representações pictóricas, nas artes visuais, pintura, escultura, cinema. Mas também a literatura, e seus textos permeados de metáforas, sinédoques e metonímias, é imagem. É essa a noção que norteia este trabalho. Considerando que a ilustração ocupa formas diversas dentro de uma obra, busco entender como se dá a interação entre texto escrito e texto visual num livro. Esta dissertação de mestrado constitui uma tentativa de explorar essas questões que dizem respeito às imagens formadas pela combinação de palavra e ilustração num livro; constitui também uma reflexão acerca de distintas formas de publicação literária em que as ilustrações se relacionam com o texto escrito de maneiras diferentes. É, finalmente, uma tentativa de definir aquilo que alguns autores têm chamado de livro ilustrado contemporâneo. A análise do corpus revela que as ilustrações agem no interior da obra, recriam imagens. Ocupam, portanto, lugar de criação, abrindo frestas na própria linguagem para ampliar as possibilidades de leitura e a percepção do mundo.Abstract : This dissertation aims to understand the narrative role played by illustrations in contemporary Brazilian children's literature and, most importantly, what they offer as image reading possibilities to the critical and aesthetic reader. To achieve that, I analyze the relationships between written text and illustrations in books recently edited in Brazil, particularly those published since 2000. The word image is often associated with pictorial representations in the visual arts, however, children's literature, with its reliance on metaphors, sinedoques, and metonymies, is permeated with images. Firstly, I consider illustrations as elements that amplify the text, according to the artist's point of view. Secondly, I explore the notion that illustrations do more than visually represent the written text, by considering them as separate elements that transform the original text when both are jointly organized on the pages of a book. Finally, I propose the idea that besides amplifying and/or transforming the written text, illustrations can be considered as polysemic elements that generate critical images that "touch reality," although not intending to portray it in a closed, stagnant manner. The analysis of the selected works reveals that illustrations act from within the body of the work, recreating images. Therefore they occupy a creative space, as they open gaps in language to amplify the possibilities of interpreting reading and world perception
Growth, History, or Institutions? What Explains State Fragility in Sub-Saharan Africa
No full textWe explore the determinants of state fragility in sub-Saharan Africa. Controlling for a wide range of economic, demographic, geographic and istitutional regressors, we find that institutions, and in particular the civil liberties index and the number of revolutions, are the main determinants of fragility, even taking into account their potential endogeneity. Economic factors such as income growth and investment display a non robust impact after controlling for omitted variables and reverse causality. Colonial variables reflecting the history of the region display a marginal impact on fragility once institutions are accounted for.State fragility, Africa, institutions, colonial history.
