All two dimensional links are null homotopic

We show that any number of disjointly embedded 2-spheres in 4-space can be pulled apart by a link homotopy, ie, by a motion in which the 2-spheres stay disjoint but are allowed to self-intersect.Comment: 18 pages. Published copy, also available at http://www.maths.warwick.ac.uk/gt/GTVol3/paper10.abs.htm

Ape: An Expert System for Automatic Programming from Abstract Specifications of Data Types and Algorithms

The APE (Automatic Programming Expert) system constructs executable and efficient programs from algebraic specifications of abstract data types, and abstract algorithms given as conditional term-rewrite-rule-systems with terms built up from operation symbols of the abstract data types involved. The APE is an experimental system devised to develop methods for codifying a rather Broad extent of programming knowledge required to construct implementations of data types and algorithms. For data type specifications, the APE admits hidden operations, conditional axioms, and parameterized data types. The APE automatically implements algebraic specifications of all commonly known data types in terms of clusters of INTERLISP-functions. The APE constructs executable implementations of a variety of sorting and searching algorithms. As an experimental prototype, the APE demonstrates that a knowledge-based programming paradigm provides a useful tool for partially automating an important phase of software development

Neural Classifier Systems for Histopathologic Diagnosis

Neural network and statistical classification methods were applied to derive an objective grading for moderately and poorly differentiated lesions, based on characteristics of the nuclear placement patterns. Using a multilayer network after abbreviated training as a feature extractor followed by a quadratic Bayesian classifier allowed grade assignment agreeing with visual diagnostic consensus in 96% of fields from the training set of 500 fields, and a 77% of 130 fields of a test set

Single-Channel and whole-cell electrophysiological characterizations of L-Type Cav1.2 Calcium channel splice variants: Relevance to cardiac and nervous system functions

Ph.DDOCTOR OF PHILOSOPH

Brief mindful yoga intervention fails to prevent depression-related outcomes after a dysphoric affect induction

ObjectivesThis study was designed to test whether a brief mindful yoga intervention can prevent depression-related responses to dysphoric events.MethodsOne-hundred-75 undergraduate participants were assigned to one of four conditions in a single-session study. Three conditions received a dysphoric affect induction. Before the induction, participants completed a 20-minute intervention consisting of (a) mindful yoga, (b) stretching, or (c) relaxation control. The fourth condition consisted of a neutral affect induction to examine the validity of the dysphoric affect induction. We hypothesized that compared to relaxation control and stretching, mindful yoga participants would show less: (H1) state depressed affect; (H2) rumination; and (H3) attentional bias toward depression-related words.ResultsValidity checks indicated that the dysphoric affect induction led to greater state depressed affect and rumination, but not attentional bias. Compared to relaxation control, mindful yoga did not show less state depression, rumination, or attentional bias. The stretching group showed less depression and rumination.ConclusionsThe results do not provide support for mindful yoga in preventing depression-related reactivity. It may be that when given in a brief, one-time dose, stretching is the better choice for preventing negative outcomes from a subsequent dysphoric experience

Brief mindful yoga intervention fails to prevent depression-related outcomes after a dysphoric affect induction

ObjectivesThis study was designed to test whether a brief mindful yoga intervention can prevent depression-related responses to dysphoric events.MethodsOne-hundred-75 undergraduate participants were assigned to one of four conditions in a single-session study. Three conditions received a dysphoric affect induction. Before the induction, participants completed a 20-minute intervention consisting of (a) mindful yoga, (b) stretching, or (c) relaxation control. The fourth condition consisted of a neutral affect induction to examine the validity of the dysphoric affect induction. We hypothesized that compared to relaxation control and stretching, mindful yoga participants would show less: (H1) state depressed affect; (H2) rumination; and (H3) attentional bias toward depression-related words.ResultsValidity checks indicated that the dysphoric affect induction led to greater state depressed affect and rumination, but not attentional bias. Compared to relaxation control, mindful yoga did not show less state depression, rumination, or attentional bias. The stretching group showed less depression and rumination.ConclusionsThe results do not provide support for mindful yoga in preventing depression-related reactivity. It may be that when given in a brief, one-time dose, stretching is the better choice for preventing negative outcomes from a subsequent dysphoric experience

Signals for Supersymmetry at HERA

We consider the baryon parity signals at HERA for the case of the MSSM production mechanisms and the decays via the lepton number violating couplings $L_iQ{\bar D}$. We can probe very small Yukawa couplings \lam' \gsim 3\cdot 10^{-6}, limited only by the decay length of the LSP. We assume the LSP to be the lightest neutralino and study its decays in detail. We present the matrix element squared for the tree-level decay amplitude of a generally mixed neutralino explicitly. We find that the branching fraction to charged leptons strongly depends on the SUSY parameters and can differ significantly from the naively expected $50\%$. The SUSY mass reaches of the studied processes in the ZEUS detector at HERA were found to be: (m({\tilde e}, {\tilde \nu})+m({\tilde q}))\leq 170\gev, 195\gev and 205\gev for the $L_\tau Q{\bar D}, L_\mu Q{\bar D}$ and $L_e Q{\bar D}$ couplings respectively. These are well above existing limits on R-parity violating (\rpv) SUSY from previous experiments. We conclude that HERA offers a {\it very promising} discovery potential for \rpv\ SUSY.Comment: 23 pages, plus 12 uuencoded figures upon request, preprint ETH-TH/94-1