Dualisation of the D=7 Heterotic String

The dualisation and the first-order formulation of the D=7 abelian Yang-Mills supergravity which is the low energy effective limit of the D=7 fully Higssed heterotic string is discussed. The non-linear coset formulation of the scalars is enlarged to include the entire bosonic sector by introducing dual fields and by constructing the Lie superalgebra which generates the dualized coset element.Comment: 20 page

Intersectional tension: a qualitative study of the effects of the COVID-19 response on survivors of violence against women in urban India

OBJECTIVES: There is a concern worldwide that efforts to address the SARS-CoV-2 pandemic have affected the frequency and intensity of domestic violence against women. Residents of urban informal settlements faced particularly stringent conditions during the response in India. Counsellors spoke with registered survivors of domestic violence in Mumbai, with two objectives: to understand how the pandemic and subsequent lockdown had changed their needs and experiences, and to recommend programmatic responses. DESIGN: Qualitative interviews and framework analysis. SETTING: A non-government support programme for survivors of violence against women, providing services mainly for residents of informal settlements. PARTICIPANTS: During follow-up telephone counselling with survivors of violence against women who had previously registered for support and consented to the use of information in research, counsellors took verbal consent for additional questions about the effects of COVID-19 on their daily life, their ability to speak with someone, and their counselling preferences. Responses were recorded as written notes. RESULTS: The major concerns of 586 clients interviewed between April and July 2020 were meeting basic needs (financial stress, interrupted livelihoods and food insecurity), confinement in small homes (family tensions and isolation with abusers) and limited mobility (power imbalances in the home and lack of opportunity for disclosure and stress relief). A major source of stress was the increased burden of unpaid domestic care, which fell largely on women. CONCLUSION: The COVID-19 pandemic has increased the burden of poverty and gendered unpaid care. Finance and food security are critical considerations for future response, which should consider inequality, financial support, prioritising continued availability of services for survivors of violence and expanding access to social networks. Decision-makers must be aware of the gendered, intersectional effects of interventions and must include residents of informal settlements who are survivors of domestic violence in the planning and implementation of public health strategies

Landslide Inventory in an Urban Setting in the Context of Chittagong Metropolitan Area, Bangladesh

Chittagong Metropolitan Area (CMA) is vulnerable to landslide hazards with an increasing trend in frequency and damage. Devastating landslides have hit CMA repeatedly in recent years. Under a project financed through ICIMOD of Nepal, detail survey has been conducted to prepare an inventory of landslides in CMA. Landslide events have been observed to occur at times of much higher rainfall amount compared to the monthly average. Moreover, rapid urbanization, increased population density, improper land-use, cutting of hills, indiscriminate deforestation and agricultural practices are aggravating the landslide vulnerability in CMA. A landslide inventory is helpful for landslide modelling, runoff modelling and urban land-use planning. A three step methodology, identifying past landslide events from news archive, information from local people and satellite image interpretation has been followed. An inventory of 57 landslide events has been prepared which includes landslide locations, types, dimension, activity, potential causes of landslides, triggering mechanism and slope stabilizing mechanism. This inventory is expected to be a useful resource for future landslide studies in this port city of Bangladesh

Kac-Moody Symmetries of Ten-dimensional Non-maximal Supergravity Theories

A description of the bosonic sector of ten-dimensional N=1 supergravity as a non-linear realisation is given. We show that if a suitable extension of this theory were invariant under a Kac-Moody algebra, then this algebra would have to contain a rank eleven Kac-Moody algebra, that can be identified to be a particular real form of very-extended D_8. We also describe the extension of N=1 supergravity coupled to an abelian vector gauge field as a non-linear realisation, and find the Kac-Moody algebra governing the symmetries of this theory to be very-extended B_8. Finally, we discuss the related points for the N=1 supergravity coupled to an arbitrary number of abelian vector gauge fields

Locating Boosted Kerr and Schwarzschild Apparent Horizons

We describe a finite-difference method for locating apparent horizons and illustrate its capabilities on boosted Kerr and Schwarzschild black holes. Our model spacetime is given by the Kerr-Schild metric. We apply a Lorentz boost to this spacetime metric and then carry out a 3+1 decomposition. The result is a slicing of Kerr/Schwarzschild in which the black hole is propagated and Lorentz contracted. We show that our method can locate distorted apparent horizons efficiently and accurately.Comment: Submitted to Physical Review D. 12 pages and 22 figure

Kaluza-Klein electrically charged black branes in M-theory

We present a class of Kaluza-Klein electrically charged black p-brane solutions of ten-dimensional, type IIA superstring theory. Uplifting to eleven dimensions these solutions are studied in the context of M-theory. They can be interpreted either as a p+1 extended object trapped around the eleventh dimension along which momentum is flowing or as a boost of the following backgrounds: the Schwarzschild black (p+1)-brane or the product of the (10-p)-dimensional Euclidean Schwarzschild manifold with the (p+1)-dimensional Minkowski spacetime.Comment: 16 pages, uses latex and epsf macro, figures include

U-duality and M-Theory

This work is intended as a pedagogical introduction to M-theory and to its maximally supersymmetric toroidal compactifications, in the frameworks of 11D supergravity, type II string theory and M(atrix) theory. U-duality is used as the main tool and guideline in uncovering the spectrum of BPS states. We review the 11D supergravity algebra and elementary 1/2-BPS solutions, discuss T-duality in the perturbative and non-perturbative sectors from an algebraic point of view, and apply the same tools to the analysis of U-duality at the level of the effective action and the BPS spectrum, with a particular emphasis on Weyl and Borel generators. We derive the U-duality multiplets of BPS particles and strings, U-duality invariant mass formulae for 1/2- and 1/4-BPS states for general toroidal compactifications on skew tori with gauge backgrounds, and U-duality multiplets of constraints for states to preserve a given fraction of supersymmetry. A number of mysterious states are encountered in D<=3, whose existence is implied by T-duality and 11D Lorentz invariance. We then move to the M(atrix) theory point of view, give an introduction to Discrete Light Cone Quantization (DLCQ) in general and DLCQ of M-theory in particular. We discuss the realization of U-duality as electric-magnetic dualities of the Matrix gauge theory, display the Matrix gauge theory BPS spectrum in detail, and discuss the conjectured extended U-duality group in this scheme.Comment: 132 pages, 37 tables, Latex2e; v3: minor corrections, text reformatted, update of refs, note added about boundaries of M-theory moduli space, final version to appear in Phys. Rep