Computing Optimal Morse Matchings

Morse matchings capture the essential structural information of discrete Morse functions. We show that computing optimal Morse matchings is NP-hard and give an integer programming formulation for the problem. Then we present polyhedral results for the corresponding polytope and report on computational results

Adoption by Lesbian and Gay People: The Use and Mis-Use of Social Science Research

In the past twenty years, openly lesbian and gay people have joined in the evolving national dialogue, within the law and elsewhere, about adoption. This Article considers the adoption dialogue, addressing in particular the facts and beliefs that sometimes form (both by informing and misinforming) the dialogue. Part I of this Article describes the ways in which lesbian and gay people confront adoption\u27s legal structures. Part II discusses the findings of social science research on parenting by lesbian and gay people. Part III reviews and analyzes some of the responses to this research. The Conclusion considers the nature of the discussions regarding the research and suggests a mode of reconstruction. I. The Legal Structures of Adoption The legal process of adoption intersects with the lives of lesbian and gay people in a variety of ways. The most common are (1) second parent adoptions in which a lesbian or gay person adopts the child of a partner, and (2) traditional adoptions, in which a lesbian or gay person adopts a foster child or a child whom the adoptive parent has previously not cared for. 1 The traditional form of adoption extinguishes the parental rights and obligations of the biological or legal parent so that the adoptive parent becomes the sole parent. Second parent adoption, however, leaves the parental rights of one legally recognized parent intact and creates a second legally recognized parent for the child. These adoptions have become fairly routine among children of heterosexual step-parents, though typically pursuant to ..

The human and mammalian cerebrum scale by computational power and information resistance

The cerebrum of mammals spans a vast range of sizes and yet has a very regular structure. The amount of folding of the cortical surface and the proportion of white matter gradually increase with size, but the underlying mechanisms remain elusive. Here, two laws are derived to fully explain these cerebral scaling relations. The first law holds that the long-range information flow in the cerebrum is determined by the total cortical surface (i.e., the number of neurons) and the increasing information resistance of long-range connections. Despite having just one free parameter, the first law fits the mammalian cerebrum better than any existing function, both across species and within humans. According to the second law, the white matter volume scales, with a few minor corrections, to the cortical surface area. It follows from the first law that large cerebrums have much local processing and little global information flow. Moreover, paradoxically, a further increase in long-range connections would decrease the efficiency of information flow.Comment: 15 pages, 2 figures; 3 supplement

Computing the Face Lattice of a Polytope from its Vertex-Facet Incidences

We give an algorithm that constructs the Hasse diagram of the face lattice of a convex polytope P from its vertex-facet incidences in time O(min{n,m}*a*f), where n is the number of vertices, m is the number of facets, a is the number of vertex-facet incidences, and f is the total number of faces of P. This improves results of Fukuda and Rosta (1994), who described an algorithm for enumerating all faces of a d-polytope in O(min{n,m}*d*f^2) steps. For simple or simplicial d-polytopes our algorithm can be specialized to run in time O(d*a*f). Furthermore, applications of the algorithm to other atomic lattices are discussed, e.g., to face lattices of oriented matroids.Comment: 14 pages; to appear in: Comput. Geom.; the new version contains some minor extensions and corrections as well as a more detailed treatment of oriented matroid

The use of drug calendars for the diagnosis of cutaneous drug eruptions in the age of electronic medical records

A morbilliform drug eruption is the most common condition leading to a dermatology consultation for a patient in the hospital. Timing is an important diagnostic tool since the onset of a skin rash usually takes place within days-to-weeks of the start of the implicated drug. A comprehensive, thorough, and reliable drug history by the clinician is essential. Therefore, to assist in the task of determining the causative medication of a new skin rash in a hospitalized patient, the creation of a drug calendar is recommended. The development of an electronic version of the drug calendar offers several benefits over the manual version. As the use of electronic medical records continues to become the standard in medicine, the electronic drug calendar will serve as an invaluable tool for the diagnosis of drug hypersensitivity