General Static N=2 Black Holes

We find general static BPS black hole solutions for general N=2, d=4 supergravity theories with an arbitrary number of vector multiplets. These solutions are completely specified by the K\"ahler potential of the underlying special K\"ahler geometry and a set of constrained harmonic functions.Comment: Latex, 7 pages, typos corrected, version to appear in MPL

Black Holes and Flop Transitions in M-Theory on Calabi-Yau Threefolds

We present fivedimensional extreme black hole solutions of M-theory compactified on Calabi-Yau threefolds and study these solutions in the context of flop transitions in the extended Kahler cone. In particular we consider a specific model and present black hole solutions, breaking half of N=2 supersymmetry, in two regions of the extended Kahler cone, which are connected by a flop transition. The conditions necessary to match both solutions at the flop transition are analysed. Finally we also discuss the conditions to obtain massless black holes at the flop transition.Comment: 19 pp, LaTe

Conformal Solutions Of Duality Invariant 2D Magnetohydrodynamic Turbulence

We consider possible conformal field theory (CFT) descriptions of the various inertial ranges that exist in $2d$ duality invariant Magnetohydrodynamics. Such models arise as effective theories of dyonic plasmas in 3 dimensions in which all fields are independent of the third coordinate. We find new constraints on the allowed CFT's compared to those that may describe turbulence in $2d$ plasmas of electric charges only. The predictions from CFT concerning equipartition of energy amongst the electric and magnetic fields are discussed, and quantities exhibiting universal scaling are derived.Comment: Latex, 8 page

Duality Invariant Magnetohydrodynamics And Dyons

The theory of magnetohydrodynamics is extended to the cases of a plasma of separate magnetic and electric charges, as well as to a plasma of dyons respectively. In both these cases the system possesses electric-magnetic duality symmetry. In the former case we find that because of the existence of two independent generalized Ohm's law equations, the limit of infinite electric and magnetic conductivity results in the vanishing of both electric and magnetic fields, as well as the corresponding currents. In the dyonic case, we find that the resulting duality-invariant system of equations are equivalent to those of ordinary MHD, after suitable field redefinitions.Comment: 11 pages, late

Branes and Fluxes in D=5 Calabi-Yau Compactifications of M-Theory

We discuss Poincare three-brane solutions in D=5 M-Theory compactifications on Calabi-Yau (CY) threefolds with G-fluxes. We show that the vector moduli freeze at an attractor point. In the case with background flux only, the spacetime geometry contains a zero volume singularity with the three-brane and the CY space shrinking simultaneously to a point. This problem can be avoided by including explicit three-brane sources. We consider two cases in detail: a single brane and, when the transverse dimension is compactified on a circle, a pair of branes with opposite tensions.Comment: 14 pages, final versio

Meeting the standards during a global pandemic: A mixed methods study of FEPAC accredited forensic science educational programs

Introduction: Standardization is used to ensure consistency and reduce variability within a given field such as forensic education. Evaluating how Forensic Science Education Programs Accreditation Commission’s (FEPAC) programs met select standards during a public health crisis may help us to understand its impact. To this end, an explanatory sequential mixed methods design employing Grounded Theory was utilized. The purpose of this study was to evaluate FEPAC accredited masters’ programs and how accreditation standards were met with a focus on the effect of a global pandemic in four core areas.Methods: Twenty-one FEPAC masters’ programs were identified. Qualtrics was used to collect data on core standards, followed by qualitative interviews to further expand on initial findings. Interview data was analyzed with ATLAS.ti to identify themes in responses to questions. Procedures and materials were approved by Oklahoma State University Institutional Review Board.Results: Of the 21 programs, 13 (~62%) of program directors completed the survey. Pre-pandemic, ~77% of programs offered traditional education (Core 1) with only 23% offering online courses. No programs offered online formats for more than 25% of courses. March 2020 through 2020-2021 academic year, there was variability in the number of courses offered online from 25-100% of program’s coursework. Respondents indicated moving forward a decrease in in-person courses with 62% and increase in online courses at 31%. Prior to March 2020, 100% specified that all laboratory courses were offered in in-person settings. Following March 2020, 62% in-person, 31% hybrid, and 8% offered online laboratory courses. All (100%) responded that laboratory courses would return to be offered in-person after the pandemic. All (100%) of program directors responded that they did not lose faculty members directly due to the pandemic (Core 2). Professional involvement (Core 3) remained relatively unchanged with slight shifts after March 2020. Changes to institutional support (Core 4) were identified with 54% of budgets remaining the same, 31% decreased funding, and only 8% of programs experiencing an increase in support or were not sure (8%). Post- questionnaire interviews revealed overarching themes including: Impact of the Global Pandemic, Challenges, Faculty and Student Interaction, Professional Involvement, Perceptions of Online Learning, Learning, and Positive Effects.Conclusion: Overall, programs experienced impacts to their course offerings (lecture and laboratory) due to the global pandemic. However, most programs returned to pre-pandemic approaches (i.e., in-person coursework). Professional involvement for students and faculty was not significantly impacted; however, institutional support was reported to have increased or decreased for almost 39% of the programs. Themes identified focused on students receiving the training and education needed for degree completion (education, professionalism, available faculty, and resources) and the challenges the pandemic had on faculty and students

Five Dimensional Minimal Supergravities and Four Dimensional Complex Geometries

We discuss the relation between solutions admitting Killing spinors of minimal supergravities in five dimensions and four dimensional complex geometries. In the ungauged case (vanishing cosmological constant \Lambda=0) the solutions are determined in terms of a hyper-Kahler base space; in the gauged case (\Lambda<0) the complex geometry is Kahler; in the de Sitter case (\Lambda>0) the complex geometry is hyper-Kahler with torsion (HKT). In the latter case some details of the derivation are given. The method for constructing explicit solutions is discussed in each case.Comment: 8 pages. Contribution to the Proceedings of the Spanish Relativity Meeting 2008 in Salamanca, Spai

Inverse problems with hybrid lenses

We design lenses composed of a combination of standard freeform refracting surface and flat metasurface refracting an arbitrary incident field into a collimated beam with a fixed direction. In the near-field case, we study the existence of such lenses refracting a bright object into a predefined image at the target

Origin and Function of Thy-1+ Dendritic Epidermal Cells in Mice

The epidermis of normal mouse skin incorporates a newly-recognized population of dendritic cells which express relatively large amounts of the cell surface glycoprotein, Thy-1 antigen. These cells, termed Thy-1+dEC, are distinct from both epidermal Langerhans cells (LC) and melanocytes, and they populate cutaneous sites in surface densities which range to as high as 580 cells/mm2, approximately two-thirds that of LC. Studies of lethally irradiated mice which were reconstituted with semiallogeneic bone marrow cells and mice which received grafts of semiallogeneic skin have demonstrated that some, if not all, Thy-1+dEC are of bone marrow origin, and that they are capable of migrating into epidermis from a vascular source. Thy-1+dEC expressed both asialo GM1 and a cell surface determinant recognized by the monoclonal antibody 20–10–5S, further suggesting their functions will be included among those normally ascribed to lymphoreticular cells. Isolation of epidermal cells with the Fluorescence Activated Cell Sorter (FACS) was successful in producing relatively pure populations of Thy-1+dEC and LC. Such technological advances as this should facilitate testing several hypotheses concerning the ultimate function of these cells, including the possibilities that they are antigen-presenting cells which selectively activate down-regulating signals, T lymphocytes, natural killer (NK) cells, or natural suppressor (NS) cells