From 2D Integrable Systems to Self-Dual Gravity

We explain how to construct solutions to the self-dual Einstein vacuum equations from solutions of various two-dimensional integrable systems by exploiting the fact that the Lax formulations of both systems can be embedded in that of the self-dual Yang--Mills equations. We illustrate this by constructing explicit self-dual vacuum metrics on $\R^2\times \Sigma$, where $\Sigma$ is a homogeneous space for a real subgroup of SL(2, \C) associated with the two-dimensional system.Comment: 9 pages, LaTex, no figure

Cleft Extensions and Quotients of Twisted Quantum Doubles

Given a pair of finite groups $F, G$ and a normalized 3-cocycle $\omega$ of $G$, where $F$ acts on $G$ as automorphisms, we consider quasi-Hopf algebras defined as a cleft extension $\Bbbk^G_\omega\#_c\,\Bbbk F$ where $c$ denotes some suitable cohomological data. When $F\rightarrow \overline{F}:=F/A$ is a quotient of $F$ by a central subgroup $A$ acting trivially on $G$, we give necessary and sufficient conditions for the existence of a surjection of quasi-Hopf algebras and cleft extensions of the type $\Bbbk^G_\omega\#_c\, \Bbbk F\rightarrow \Bbbk^G_\omega\#_{\overline{c}} \, \Bbbk \overline{F}$. Our construction is particularly natural when $F=G$ acts on $G$ by conjugation, and $\Bbbk^G_\omega\#_c \Bbbk G$ is a twisted quantum double $D^{\omega}(G)$. In this case, we give necessary and sufficient conditions that Rep($\Bbbk^G_\omega\#_{\overline{c}} \, \Bbbk \overline{G}$) is a modular tensor category.Comment: LaTex; 14 page

Staple Food Consumption Patterns in Urban Zambia: Results from the 2007/2008 Urban Consumption Survey

• The Zambia Urban Consumption Survey, a survey of 1,865 urban households in Lusaka, Kitwe, Mansa, and Kasama, was conducted in August 2007 and February 2008 by the Central Statistical Office in collaboration with the Zambia Food Security Research Project. • Survey results indicate that in Lusaka and Kitwe, wheat has overtaken maize as the most important staple in terms of urban consumer expenditures. Maize is no longer the dominant staple food in urban Zambia, except among the poor. This finding is consistent with broader regional trends toward declining dependence on maize for urban staple food needs. • Hammer-milling services are readily available to the vast majority of urban households and in most cases their cheapest maize meal option is to obtain maize grain and have it custom-milled for a fee. However, maize grain is not consistently available in public markets during the lean season (December-March). GRZ could promote urban food security by ensuring that maize grain is available in public markets at all times. • In Kasama and Mansa, and particularly among relatively poor households, cassava is an important consumption item and serves as a buffer against high maize prices and poor maize grain availability during the lean season. • Supermarkets have only 5-17% of the market share for staple foods and are frequented mainly by wealthier households. Urban consumers are heavily dependent upon non-supermarket, informal retail outlets such as public markets and grocers for their staple food purchases. Policies and public investments to support these traditional retailers, help them operate more efficiently, and reduce the transaction costs they face may have higher payoffs for most urban consumers as well as smallholder farmers than policies presupposing the rapid takeover of supermarkets and other more formal retail channels.Zambia, food security, consumption, household, urban, Agricultural and Food Policy, Community/Rural/Urban Development, Consumer/Household Economics, Food Security and Poverty, International Development, q19,

Strong absorption and selective thermal emission from a mid-infrared metamaterial

We demonstrate thin-film metamaterials with resonances in the mid-infrared wavelength range. Our structures are numerically modeled and experimentally characterized by reflection and angularly-resolved thermal emission spectroscopy. We demonstrate strong and controllable absorption resonances across the mid-infrared wavelength range. In addition, the polarized thermal emission from these samples is shown to be highly selective and largely independent of emission angles from normal to 45 degrees. Experimental results are compared to numerical models with excellent agreement. Such structures hold promise for large-area, low-cost metamaterial coatings for control of gray- or black-body thermal signatures, as well as for possible mid-IR sensing applications.Comment: The following article has been submitted to Appl. Phys. Lett. After it is published, it will be found at http://apl.aip.org/. 14 pages including 4 figure page

Sexuality at the Bar: An Empirical Exploration into the Experiences of LGBT+ Barristers in England & Wales

The Bar of England & Wales is an historic, traditional institution of courtroom advocates and specialist advisers that can trace its origins back to the 13th century. As a field of study, there is comparatively little academic work on barristers. Where work has been done on the Bar, and in relation to diversity at the Bar, this has tended to focus either wholly or primarily on women barristers and suggests patterns of inequality, exclusion and forms of direct and indirect discrimination. Like the other branches of the legal profession in England and Wales, the Bar does not reflect the society it serves. In their world-first research, ‘Sexuality at the Bar’, Mason and Vaughan show a variety of complex practices which govern where (and when and how) LGBT+ members of the Bar feel comfortable being open about their sexuality as well as highlighting a significant number of LGBT+ barristers who have experienced work related bullying and/or discrimination. Their work also suggests an increasing role for Bar-specific LGBT+ networks and the value of LGBT+ role models, both at the Bar and in the judiciary

A Study of the Relationship Between Antivirus Regressions and Label Changes

AntiVirus (AV) products use multiple components to detect malware. A component which is found in virtually all AVs is the signature-based detection engine: this component assigns a particular signature label to a malware that the AV detects. In previous analysis [1-3], we observed cases of regressions in several different AVs: i.e. cases where on a particular date a given AV detects a given malware but on a later date the same AV fails to detect the same malware. We studied this aspect further by analyzing the only externally observable behaviors from these AVs, namely whether AV engines detect a malware and what labels they assign to the detected malware. In this paper we present the results of the analysis about the relationship between the changing of the labels with which AV vendors recognize malware and the AV regressions

Simulating Tsunami Inundation and Soil Response in a Large Centrifuge.

Tsunamis are rare, extreme events and cause significant damage to coastal infrastructure, which is often exacerbated by soil instability surrounding the structures. Simulating tsunamis in a laboratory setting is important to further understand soil instability induced by tsunami inundation processes. Laboratory simulations are difficult because the scale of such processes is very large, hence dynamic similitude cannot be achieved for small-scale models in traditional water-wave-tank facilities. The ability to control the body force in a centrifuge environment considerably reduces the mismatch in dynamic similitude. We review dynamic similitudes under a centrifuge condition for a fluid domain and a soil domain. A novel centrifuge apparatus specifically designed for exploring the physics of a tsunami-like flow on a soil bed is used to perform experiments. The present 1:40 model represents the equivalent geometric scale of a prototype soil field of 9.6 m deep, 21 m long, and 14.6 m wide. A laboratory facility capable of creating such conditions under the normal gravitational condition does not exist. With the use of a centrifuge, we are now able to simulate and measure tsunami-like loading with sufficiently high water pressure and flow velocities. The pressures and flow velocities in the model are identical to those of the prototype yielding realistic conditions of flow-soil interaction

Gastric perforation and pancreatitis manifesting after an inadvertent nissen fundoplication in a patient with superior mesenteric artery syndrome.

Superior mesenteric artery (SMA) syndrome is an uncommon but well-recognized clinical entity. It can lead to proximal small bowel obstruction and severe morbidity and mortality in lieu of late diagnosis and concomitant existing comorbidities. We report a 54-year-old female, with SMA syndrome which manifested itself after Nissen fundoplication along with two major complications. The diagnosis of SMA was established by clinical symptoms and radiological findings