Non-supersymmetric Orientifolds of Gepner Models

Starting from a previously collected set of tachyon-free closed strings, we search for N=2 minimal model orientifold spectra which contain the standard model and are free of tachyons and tadpoles at lowest order. For each class of tachyon-free closed strings -- bulk supersymmetry, automorphism invariants or Klein bottle projection -- we do indeed find non-supersymmetric and tachyon free chiral brane configurations that contain the standard model. However, a tadpole-cancelling hidden sector could only be found in the case of bulk supersymmetry. Although about half of the examples we have found make use of branes that break the bulk space-time supersymmetry, the resulting massless open string spectra are nevertheless supersymmetric in all cases. Dropping the requirement that the standard model be contained in the spectrum, we find chiral tachyon and tadpole-free solutions in all three cases, although in the case of bulk supersymmetry all massless spectra are supersymmetric. In the other two cases we find truly non-supersymmetric spectra, but a large fraction of them are nevertheless partly or fully supersymmetric at the massless level.Comment: 13 pages, 4 figure

Classification of Simple Current Invariants

We summarize recent work on the classification of modular invariant partition functions that can be obtained with simple currents in theories with a center (Z_p)^k with p prime. New empirical results for other centers are also presented. Our observation that the total number of invariants is monodromy-independent for (Z_p)^k appears to be true in general as well. (Talk presented in the parallel session on string theory of the Lepton-Photon/EPS Conference, Geneva, 1991.)Comment: 8 page

Social Constraint, Social Support and Psychological Functioning in Rural and Nonrural Cancer Survivors

This cross-sectional study identified the nature and strength of the relationship between social and psychological functioning, and explored if these relationships differ as a function of environmental and personal characteristics. Participants (n=87) consist of breast, prostate, colorectal, lung, and head and neck cancer survivors who were diagnosed within the past five years. Cancer survivors were recruited through a cancer registry and outpatient clinics. Data collection involved questionnaire and medical records review. In linear regression models for distress, social constraint demonstrated a stronger relationship with general distress (β = .37 vs. β = -.26), anxiety and depression (β = .65 vs. βs = -.21 to .-30) and cancer-specific distress (β =.62 vs. β = -.15) than social support. In the wellbeing models, social support demonstrated a stronger relationship with life satisfaction (β = .56 vs. β = -.15) and global mental health (β = .38 vs. β = -.37) than social constraint; no significant associations were found for cancer-specific wellbeing outcomes. The environmental and personal characteristics significantly moderated the relationship between social and psychological functioning in a few regression models. Results support the interrelationship between social and psychological functioning in cancer survivors, and sheds light on the complexities of these relationships

The Transition to College Process in PR-CETP Scholars

This article describes a study about the experiences of a group of students during the transition from high school to college. The students are future teachers who evidenced a high level of academic achievement in high school and received merit scholarships from the Puerto Rico Collaborative for Excellence in Teacher Preparation (PR-CETP). Two groups of students were compared: those who sustained a high GPA during their freshman year, and those who did not and, therefore, no longer qualified for the scholarship. The study was carried out through focused interviews with eight students, from three universities, four of whom maintained the scholarship and four who did not. Findings indicate that the main problems encountered were academic and social, and that the students received support from their families during the entire process. Regarding formal support, they pointed out that they felt highly satisfied with the services provided by PR-CETP and the universities, but they also pointed out (particularly those who lost the scholarship) that they needed additional services from the universities. They suggested, for example, better tutoring, and social activities among the scholars. The interviewed students, in general, consider that they faced the transition successfully since most of them described their academic, emotional, and social status as satisfactory at the time of the interviews

Magnetoelectric Cr_2 O_3 and relativity theory

Relativity theory is useful for understanding the phenomenology of the magnetoelectric effect of the antiferromagnet chromium sesquioxide Cr_2 O_3 in two respects: (i) One gets a clear idea about the physical dimensions of the electromagnetic quantities involved, in particular about the dimensions of the magnetoelectric moduli that we suggest to tabulate in future as dimensionless relative quantities; (ii) one can recognize and extract a temperature dependent, 4-dimensional pseudoscalar from the data of magnetoelectric experiments with Cr_2 O_3. This pseudoscalar piece of Cr_2 O_3 is odd under time reflections and parity transformations and is structurally related ("isomorphic") to the gyrator of electric network theory, the axion of particle physics, and the perfect electromagnetic conductor of electrical engineering.Comment: 9 pages latex, seminar at the Workshop on Magnetoelectric Interaction Phenomena in Crystals (MEIPIC-6), 25-28 Jan. 2009, Santa Barbara, US

Constraints on extra dimensions from precision molecular spectroscopy

Accurate investigations of quantum level energies in molecular systems are shown to provide a test ground to constrain the size of compactified extra dimensions. This is made possible by the recent progress in precision metrology with ultrastable lasers on energy levels in neutral molecular hydrogen (H$_2$, HD and D$_2$) and the molecular hydrogen ions (H$_2^+$, HD$^+$ and D$_2^+$). Comparisons between experiment and quantum electrodynamics calculations for these molecular systems can be interpreted in terms of probing large extra dimensions, under which conditions gravity will become much stronger. Molecules are a probe of space-time geometry at typical distances where chemical bonds are effective, i.e. at length scales of an \AA. Constraints on compactification radii for extra dimensions are derived within the Arkani-Hamed-Dimopoulos-Dvali framework, while constraints for curvature or brane separation are derived within the Randall-Sundrum framework. Based on the molecular spectroscopy of D$_2$ molecules and HD$^+$ ions, the compactification size for seven extra dimensions (in connection to M-theory defined in 11 dimensions) of equal size is shown to be limited to $R_7 < 0.6 \mu$m. While limits on compactification sizes of extra dimensions based on other branches of physics are compared, the prospect of further tightening constraints from the molecular method is discussed

Modelling inflation in China - a regional perspective

We model provincial inflation in China during the reform period. In particular, we are interested in the ability of the hybrid New Keynesian Phillips Curve (NKPC) to capture the inflation process at the provincial level. The study highlights differences in inflation formation and shows that the NKPC provides a reasonable description of the inflation process only for the coastal provinces. A probit analysis suggests that the forwardlooking inflation component and the output gap are important inflation drivers in provinces that have advanced most in marketisation of the economy and have most likely experienced excess demand pressures. These results have implications for the relative effectiveness of monetary policy across the Chinese provinces. JEL Classification: E31, C22China, GMM, inflation, New Keynesian Phillips curve, Regional

Arnold Hirsch Collection of Ernest N. \u27Dutch\u27 Morial Oral History Interviews, 1987: A Finding Aid

This finding aid of interviews is drawn from the Arnold R. Hirsch Collection at the Amistad Research Center. Between 1987 and 1994, historian Arnold Hirsch interviewed New Orleans’ first black mayor, Ernest Morial, and others related to that crucial era in New Orleans political history. This collection consists of 37 audiocassettes tapes that contain oral history interviews conducted by Arnold Hirsch with various New Orleanians who were active in city government and political activism. This project-based thesis covers the research and construction of the finding aid completed for this collection during an internship at the Amistad Research Center, as well as the metadata collected and created for the collection. This collection and finding aid are being housed at the Amistad Research Center