Symplectic rational blowdowns

We prove that the rational blowdown, a surgery on smooth 4-manifolds introduced by Fintushel and Stern, can be performed in the symplectic category. As a consequence, interesting families of smooth 4-manifolds, including the exotic $K3$ surfaces of Gompf and Mrowka, admit symplectic structures.Comment: 12 pages; 4 figures; Latex2e documen

Generalized symplectic rational blowdowns

We prove that the generalized rational blowdown, a surgery on smooth 4-manifolds, can be performed in the symplectic category.Comment: Version 2: Correction of a minor error pointed out by an anonymous referee, correction of typos and improvement of exposition. Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol1/agt-1-26.abs.htm

A new symplectic surgery: the 3-fold sum

AbstractWe define a symplectic surgery along positively intersecting symplectic surfaces in 4-manifolds, the generalized symplectic sum, and prove an existence theorem for the special case of a 3-fold sum. With a slight generalization of the 3-fold sum, we show how to sum along immersed surfaces and indicate a relation between the sums and algebraic desingularization. We use images of the moment map for a torus acting in the neighborhood of intersection points to illustrate when it is possible to perform the proposed sums

Correspondence to Elizabeth ( Bessie ) McCaw Boggs Taylor, September 7, 1879 - May 22, 1887

Correspondence to Elizabeth ( Bessie ) McCaw Boggs Taylor, September 7, 1879 - May 22, 1887. Box 2, Folder 4.https://digitalcommons.wofford.edu/littlejohnboggs/1014/thumbnail.jp

How Women Living With HIV React and Respond to Learning About Canadian Law That Criminalises HIV Non-disclosure: ‘How Do You Prove That You Told?’

The Women, ART and the Criminalization of HIV Study is a qualitative, arts-based research study focusing on the impact of the HIV non-disclosure law on women living with HIV in Canada. The federal law requires people living with HIV to disclose their HIV-positive status to sexual partners before engaging in sexual activities that pose what the Supreme Court of Canada called a ‘realistic possibility of transmission’. Drawing on findings from seven education and discussion sessions with 48 women living with HIV regarding HIV non-disclosure laws in Canada, this paper highlights the ways in which women living with HIV respond to learning about the criminalisation of HIV non-disclosure. The most common emergent themes included: the way the law reproduces social and legal injustices; gendered experiences of intimate injustice; and the relationship between disclosure and violence against women living with HIV. These discussions illuminate the troubling consequences inherent in a law that is antithetical to the science of HIV transmission risk, and that fails to acknowledge the multiple barriers to HIV disclosure that women living with HIV experience. Women’s experiences also highlight the various ways the law contributes to their experiences of sexism, racism and other forms of marginalisation in society

A Fine-Structure Map of Spontaneous Mitotic Crossovers in the Yeast Saccharomyces cerevisiae

Homologous recombination is an important mechanism for the repair of DNA damage in mitotically dividing cells. Mitotic crossovers between homologues with heterozygous alleles can produce two homozygous daughter cells (loss of heterozygosity), whereas crossovers between repeated genes on non-homologous chromosomes can result in translocations. Using a genetic system that allows selection of daughter cells that contain the reciprocal products of mitotic crossing over, we mapped crossovers and gene conversion events at a resolution of about 4 kb in a 120-kb region of chromosome V of Saccharomyces cerevisiae. The gene conversion tracts associated with mitotic crossovers are much longer (averaging about 12 kb) than the conversion tracts associated with meiotic recombination and are non-randomly distributed along the chromosome. In addition, about 40% of the conversion events have patterns of marker segregation that are most simply explained as reflecting the repair of a chromosome that was broken in G1 of the cell cycle