Fractional Quantum Hall Effect from Anomalies in WZNW Model

An approach to understand Fractional Quantum Hall Effect (FQHE) using anomalies is studied in this paper. More specifically, this is done by looking at the anomaly in the current conservation equation of a WZNW theory describing fields living at the edge of the two dimensional Hall sample. This WZNW theory itself comes from the non-Abelian bosonisation of fermions living at the edge. It is shown that this model can describe both integer and fractional quantization of conductivities in a unified manner.Comment: 14 pages, SU-4240-56

Living at the Edge: A Large Deviations Approach to the Outage MIMO Capacity

Using a large deviations approach we calculate the probability distribution of the mutual information of MIMO channels in the limit of large antenna numbers. In contrast to previous methods that only focused at the distribution close to its mean (thus obtaining an asymptotically Gaussian distribution), we calculate the full distribution, including its tails which strongly deviate from the Gaussian behavior near the mean. The resulting distribution interpolates seamlessly between the Gaussian approximation for rates $R$ close to the ergodic value of the mutual information and the approach of Zheng and Tse for large signal to noise ratios $\rho$. This calculation provides us with a tool to obtain outage probabilities analytically at any point in the $(R, \rho, N)$ parameter space, as long as the number of antennas $N$ is not too small. In addition, this method also yields the probability distribution of eigenvalues constrained in the subspace where the mutual information per antenna is fixed to $R$ for a given $\rho$. Quite remarkably, this eigenvalue density is of the form of the Marcenko-Pastur distribution with square-root singularities, and it depends on the values of $R$ and $\rho$.Comment: Accepted for publication, IEEE Transactions on Information Theory (2010). Part of this work appears in the Proc. IEEE Information Theory Workshop, June 2009, Volos, Greec

Living at the Edge: Religion, Capitalism, and the End of the Nation-State in Taiwan

This is a preprint (author's original) version of an article published in the journal Public Culture in 2000. The final version of this article may be found at http://dx.doi.org/10.1215/08992363-12-2-477 (login may be required)

Living at the Edge: American Low-Income Children and Families

By analyzing data from the Current Population Survey March Supplements, Living at the Edge explores the following questions about children in low-income families in the United States: What are the overall changes in the low-income and poverty rates for children over the past quarter century? How has the population of children in low-income families changed over the past decade? Which children are more likely to live in low-income families? How have changes in parental employment status affected the likelihood of children living in low-income families? What are the state by state variations in child low-income and poverty rates, and how have these changed in the last decade? How does a more inclusive definition of family income and expenses affect our understanding of the poverty and near-poverty rates of children in low-income families? This report helps document significant improvements in the child low-income rate as well as the significant decrease in the proportion of children who relied on public assistance during the 1990s. However, Living at the Edge also finds a notable increase in the share of children who lived in near-poor families (those with incomes between 100 and 200 percent of the poverty line) among children in low-income families during the 1990s. Many disadvantaged groups of children, including those with young parents, minority parents, parents with limited education, or unmarried parents, were less likely to live in poor or low-income families in the late 1990s than such children a decade earlier. The improvement in the child low-income rates of these disadvantaged groups was closely related to an increase in parental employment during the late 1990s. However, the low-income rate worsened for children whose more educated parent had a high-school diploma but no college education. For children of many disadvantaged social groups, parental employment appears to do less to protect them from economic hardship then it did a decade earlier. The groups that suffered the most in reduced economic security given parental employment status were those in the medium risk ranks (children in families with at least one parent between ages 25 to 39, children whose more educated parent had only has a high school diploma, and in father-only families). The report also notes that the official measure of poverty ignores the burden of medical and work related expenses as well as taxes and therefore tends to underestimate the share of children in near-poor and low-income families facing economic insecurity. Finally, we discuss the policy implications for our findings

Élet egy kisváros peremén = Living at the edge of a small town

Municipal governments and citizens continually shape and differentiate spaces. These spaces map social distances by their spatial isolation. Out of the three social housing blocks in a small town of the Great Plain, the lowest-status settlement’s history encompasses a former distinguished officers’ residence that turned into a Roma ghetto. Several factors played equally important roles in taking the social housing estate to a position on the edge, not only spatially but also socially: On the one hand, it was the demolition of the former settlements and the ensuing enforced mobility, the housing policy of the town and the unequal allocation of social housing units, on the other hand, it was the selection processes evolving in the marginalised block. In the eyes of the majority, the population of the settlement seems socially and ethnically homogenous and it is uniformly stigmatised by the local institutions and the other inhabitants. Analysing both financial stability and survival strategies of the block’s residents, we have found that families living there show rather large differences in this respect, and that they constitute a heterogeneous population. The settlement comprises people living in differing socio-economic conditions; one circle of families lives in a relatively stable situation with steady incomes, another is in unstable, uncertain circumstances, while there are indebted families living from one day to another and expecting their eviction from their tenement any time. Tenants identified with relatively stable backgrounds are both the ones that moved in first into the social housing block and the well embedded families who are gaining stability through their personal social networks. Whereas the situation of newcomers – those who recently moved in from predominantly lower-status areas of the town, temporary family shelters or from farm buildings in the outer areas – is the most unstable. However, even those families with the most stable financial background cannot afford to buy an independent home or rent a flat on the private market. Spatial and, consequently, social mobility is almost impossible for those occupants. Between families having lived side by side for years and decades, tight, sometimes familial relations are woven. These relations help in everyday survival but also keep those families isolated in their inner – hermetic - social network. In parallel with the marginalisation of the settlement, the binding connections that can advance the survival of these families became more and more important while linkages toward other social groups and the majority institutions that could foster spatial and social mobility are lost

An Anarchist's reflection on the political economy of everyday life

James Scott has written a detailed ethnography on the lives of the peoples of upland Southeast Asia who choose to escape oppressive government by living at the edge of their civilization. To the political economist the fascinating story told by Scott provides useful narratives in need of analytical exposition. There remains in this work a “plea for mechanism”; the mechanisms that enable social cooperation to emerge among individuals living outside the realm of state control. Social cooperation outside the formal rules of governance, nevertheless require “rules” of social intercourse, and techniques of “enforcement” to ensure the disciplining of opportunistic behavior.economic development; self-regulation; political economy; peasant economy

An anarchist’s reflection on the political economy of everyday life

James Scott has written a detailed ethnography on the lives of the peoples of upland Southeast Asia who choose to escape oppressive government by living at the edge of their civilization. To the political economist the fascinating story told by Scott provides useful narratives in need of analytical exposition. There remains in this work a “plea for mechanism”; the mechanisms that enable social cooperation to emerge among individuals living outside the realm of state control. Social cooperation outside the formal rules of governance, nevertheless require “rules” of social intercourse, and techniques of “enforcement” to ensure the disciplining of opportunistic behavior.economic development; self-regulation; political economy; peasant economy

Living at the edge: biogeographic patterns of habitat segregation conform to speciation by niche expansion in Anopheles gambiae

<p>Abstract</p> <p>Background</p> <p>Ongoing lineage splitting within the African malaria mosquito <it>Anopheles gambiae </it>is compatible with ecological speciation, the evolution of reproductive isolation by divergent natural selection acting on two populations exploiting alternative resources. Divergence between two molecular forms (M and S) identified by fixed differences in rDNA, and characterized by marked, although incomplete, reproductive isolation is occurring in West and Central Africa. To elucidate the role that ecology and geography play in speciation, we carried out a countrywide analysis of <it>An. gambiae </it>M and S habitat requirements, and that of their chromosomal variants, across Burkina Faso.</p> <p>Results</p> <p>Maps of relative abundance by geostatistical interpolators produced a distinct pattern of distribution: the M-form dominated in the northernmost arid zones, the S-form in the more humid southern regions. Maps of habitat suitability, quantified by Ecological Niche Factor Analysis based on 15 eco-geographical variables revealed less contrast among forms. M was peculiar as it occurred proportionally more in habitat of marginal quality. Measures of ecological niche breadth and overlap confirmed the mismatch between the fundamental and realized patterns of habitat occupation: forms segregated more than expected from the extent of divergence of their environmental envelope – a signature of niche expansion. Classification of chromosomal arm 2R karyotypes by multilocus genetic clustering identified two clusters loosely corresponding to molecular forms, with 'mismatches' representing admixed individuals due to shared ancestral polymorphism and/or residual hybridization. In multivariate ordination space, these karyotypes plotted in habitat of more marginal quality compared to non-admixed, 'typical', karyotypes. The distribution of 'typical' karyotypes along the main eco-climatic gradient followed a consistent pattern within and between forms, indicating an adaptive role of inversions at this geographical scale.</p> <p>Conclusion</p> <p>Ecological segregation between M and S is consistent with niche expansion into marginal habitats by chromosomal inversion variants during early lineage divergence; presumably, this process is promoted by inter-karyotype competition in the higher-quality core habitat. We propose that the appearance of favourable allelic combinations in other regions of suppressed recombination (e.g. pericentromeric portions defining speciation islands in <it>An. gambiae</it>) fosters development of reproductive isolation to protect linkage between separate chromosomal regions.</p

Postpartum cessation of urban space use by a female baboon living at the edge of the City of Cape Town

Species with slow life history strategies that invest in few offspring with extended parental care need to adapt their behavior to cope with anthropogenic changes that occur within their lifetime. Here we show that a female chacma baboon (Papio ursinus) that commonly ranges within urban space in the City of Cape Town, South Africa, stops using urban space after giving birth. This change of space use occurs without any significant change in daily distance traveled or social interactions that would be expected with general risk-sensitive behavior after birth. Instead, we suggest this change occurs because of the specific and greater risks the baboons experience within the urban space compared to natural space, and because leaving the troop (to enter urban space) may increase infanticide risk. This case study can inform methods used to manage the baboons' urban space use in Cape Town and provides insight into how life history events alter individuals' use of anthropogenic environments