How far can stochastic and deterministic views be reconciled?

In this short note, we try to provide the reader with a brief pedagogical account of some similarities and differences between stochastic and deterministic processes. A short presentation of some basic notions related to the mathematical description of stochastic processes is also given. Our main aim is to illustrate the somehow surprising fact that the gap between the behaviour of stochastic and deterministic processes might, from a practical perspective, be much smaller than a priori expected.Comment: 8 pages, pedagogical note, proceedings of the conference "Chance at the Heart of the Cell" (Lyon, November 2011), to appear in Progress in Biophysics and Molecular Biolog

The Top Ten List of Gravitational Lens Candidates from the HST Medium Deep Survey

A total of 10 good candidates for gravitational lensing have been discovered in the WFPC2 images from the HST Medium Deep Survey (MDS) and archival primary observations. These candidate lenses are unique HST discoveries, i.e. they are faint systems with sub-arcsecond separations between the lensing objects and the lensed source images. Most of them are difficult objects for ground-based spectroscopic confirmation or for measurement of the lens and source redshifts. Seven are ``strong lens'' candidates which appear to have multiple images of the source. Three are cases where the single image of the source galaxy has been significantly distorted into an arc. The first two quadruply lensed candidates were reported in Ratnatunga et al 1995 (ApJL, 453, L5) We report on the subsequent eight candidates and describe them with simple models based on the assumption of singular isothermal potentials. Residuals from the simple models for some of the candidates indicate that a more complex model for the potential will probably be required to explain the full structural detail of the observations once they are confirmed to be lenses. We also discuss the effective survey area which was searched for these candidate lens objects.Comment: 26 pages including 12 figures and 10 tables. AJ Vol. 117, No.

World Peace and Gender Equality: Addressing UN Security Council Resolution 1325’s Weaknesses

The year 2020 marks the twentieth anniversary of the passage of United Nations Security Council Resolution (“UNSCR”) 1325, the most important moment in the United Nations’ efforts to achieve world peace through gender equality. Over the past several decades, the international community has strengthened its focus on gender, including the relationship between gender and international peace and security. National governments and the United Nations have taken historic steps to elevate the role of women in governance and peacebuilding. The passage of UNSCR 1325 in 2000 foreshadowed what many hoped would be a transformational shift in international law and politics. However, the promise of gender equality has gone largely unrealized, despite the uncontroverted connection between treatment of women and the peacefulness of a nation. This Article argues for the first time that to achieve international peace and security through gender equality, the United Nations Security Council should transition its approach from making recommendations and suggestions to issuing mandatory requirements under Chapter VII of the U.N. Charter. If the Security Council and the international community believe gender equality is the best indicator of sustainable peace, then the Security Council could make a finding under Article 39 with respect to ‘a threat to the peace’—States who continue to mistreat women and girls pose a threat to international peace and security. Such a finding would trigger the Security Council’s mandatory authority to direct States to take specific actions. In exercising its mandatory authority, the Security Council should organize, support, and train grassroots organizations and require States to do the same. It should further require States to produce a reviewable National Action Plan, detailing how each State will implement its responsibilities to achieve gender equality. The Security Council should also provide culturally sensitive oversight on domestic laws which may act as a restraint on true gender equality

Proposal for a Digital Archives Program at the Dr. Joann Rayfield Archives

A report submitted in April 2016 discussing the creation of an infrastructure for the collection and preservation of digital files by the archives of Illinois State University. Includes three possible strategies based on monetary cost and staff time, with hardware and software recommendations appropriate to each

BPS States, String Duality, and Nodal Curves on K3

We describe the counting of BPS states of Type II strings on K3 by relating the supersymmetric cycles of genus $g$ to the number of rational curves with $g$ double points on K3. The generating function for the number of such curves is the left-moving partition function of the bosonic string.Comment: 12 pages, harvma

Probability sum rules and consistent quantum histories

An example shows that weak decoherence is more restrictive than the minimal logical decoherence structure that allows probabilities to be used consistently for quantum histories. The probabilities in the sum rules that define minimal decoherence are all calculated by using a projection operator to describe each possibility for the state at each time. Weak decoherence requires more sum rules. They bring in additional variables, that require different measurements and a different way to calculate probabilities, and raise questions of operational meaning. The example shows that extending the linearly positive probability formula from weak to minimal decoherence gives probabilities that are different from those calculated in the usual way using the Born and von Neumann rules and a projection operator at each time.Comment: 14 pages, 2 figures, added discussion of tensor-product histories in response to Physics Letters A referee, corrected typ

A-twisted Landau-Ginzburg models

In this paper we discuss correlation functions in certain A-twisted Landau-Ginzburg models. Although B-twisted Landau-Ginzburg models have been discussed extensively in the literature, virtually no work has been done on A-twisted theories. In particular, we study examples of Landau-Ginzburg models over topologically nontrivial spaces - not just vector spaces - away from large-radius limits, so that one expects nontrivial curve corrections. By studying examples of Landau-Ginzburg models in the same universality class as nonlinear sigma models on nontrivial Calabi-Yaus, we obtain nontrivial tests of our methods as well as a physical realization of some simple examples of virtual fundamental class computations.Comment: 64 Pages, LaTe

GLSM's for partial flag manifolds

In this paper we outline some aspects of nonabelian gauged linear sigma models. First, we review how partial flag manifolds (generalizing Grassmannians) are described physically by nonabelian gauged linear sigma models, paying attention to realizations of tangent bundles and other aspects pertinent to (0,2) models. Second, we review constructions of Calabi-Yau complete intersections within such flag manifolds, and properties of the gauged linear sigma models. We discuss a number of examples of nonabelian GLSM's in which the Kahler phases are not birational, and in which at least one phase is realized in some fashion other than as a complete intersection, extending previous work of Hori-Tong. We also review an example of an abelian GLSM exhibiting the same phenomenon. We tentatively identify the mathematical relationship between such non-birational phases, as examples of Kuznetsov's homological projective duality. Finally, we discuss linear sigma model moduli spaces in these gauged linear sigma models. We argue that the moduli spaces being realized physically by these GLSM's are precisely Quot and hyperquot schemes, as one would expect mathematically.Comment: 57 pp, LaTeX; v3: refs added, material on weighted Grassmannians adde