Calabi-Yau manifolds from pairs of non-compact Calabi-Yau manifolds

Most of Calabi-Yau manifolds that have been considered by physicists are complete intersection Calabi-Yau manifolds of toric varieties or some quotients of product types. Purpose of this paper is to introduce a different and rather new kind of construction method of Calabi-Yau manifolds by pasting two non-compact Calabi-Yau manifolds. We will also in some details explain a curious and mysterious similarity with construction of some $G_2$-manifolds (also called Joyce manifolds), which are base spaces for M-theory.Comment: 10 pages. Accepted for publication in JHE

Factors Influencing the Intention to Quit Drinking Alcohol Among African American/Black Pregnant Women

Factors influencing the intention to quit drinking alcohol among pregnant African American/Black women in San Bernardino and Riverside counties, California were investigated using the theory of planned behavior. Qualitative data were collected via focus groups from 22 pregnant women to ascertain behavioral outcomes, normative, and control beliefs associated with drinking during pregnancy. These data were used to develop a quantitative questionnaire. One hundred forty eight questionnaires were analyzed. Most of the women (86%) reported current alcohol use and 14% were former users. When adjusted for attenuation the correlation of intention with perceived control was .89, attitude .80, and subjective norm .77 all of which were statistically significant. The prediction of these three from their underlying beliefs provides insight into factors which may need to be changed to reduce alcohol use by pregnant African American/ Black women

A New Method for Searching for Free Fractional Charge Particles in Bulk Matter

We present a new experimental method for searching for free fractional charge in bulk matter; this new method derives from the traditional Millikan liquid drop method, but allows the use of much larger drops, 20 to 100 mm in diameter, compared to the traditional method that uses drops less than 15 mm in diameter. These larger drops provide the substantial advantage that it is then much easier to consistently generate drops containing liquid suspensions of powdered meteorites and other special minerals. These materials are of great importance in bulk searches for fractional charge particles that may have been produced in the early universe.Comment: 17 pages, 5 figures in a singl PDF file (created from WORD Doc.). Submitted to Review of Scientific Instrument

Ward-Takahashi Identity with External Field in Ladder QED

We derive the Ward-Takahashi identity obeyed by the fermion-antifermion-gauge boson vertex in ladder QED in the presence of a constant magnetic field. The general structure in momentum space of the fermion mass operator with external electromagnetic field is discussed. Using it we find the solutions of the ladder WT identity with magnetic field. The consistency of our results with the solutions of the corresponding Schwinger-Dyson equation ensures the gauge invariance of the magnetic field induced chiral symmetry breaking recently found in ladder QED.Comment: new references(refs.10,11) added, 18 pages, Late

Hybrid Formalism, Supersymmetry Reduction, and Ramond-Ramond Fluxes

The supersymmetric hybrid formalism for Type II strings is used to study partial supersymmetry breaking in four and three dimensions. We use worldsheet techniques to derive effects of internal Ramond-Ramond fluxes such as torsions, superpotentials and warping.Comment: Harvmac. No figure

Damping Rates and Mean Free Paths of Soft Fermion Collective Excitations in a Hot Fermion-Gauge-Scalar Theory

We study the transport coefficients, damping rates and mean free paths of soft fermion collective excitations in a hot fermion-gauge-scalar plasma with the goal of understanding the main physical mechanisms that determine transport of chirality in scenarios of non-local electroweak baryogenesis. The focus is on identifying the different transport coefficients for the different branches of soft collective excitations of the fermion spectrum. These branches correspond to collective excitations with opposite ratios of chirality to helicity and different dispersion relations. By combining results from the hard thermal loop (HTL) resummation program with a novel mechanism of fermion damping through heavy scalar decay, we obtain a robust description of the different damping rates and mean free paths for the soft collective excitations to leading order in HTL and lowest order in the Yukawa coupling. The space-time evolution of wave packets of collective excitations unambiguously reveals the respective mean free paths. We find that whereas both the gauge and scalar contribution to the damping rates are different for the different branches, the difference of mean free paths for both branches is mainly determined by the decay of the heavy scalar into a hard fermion and a soft collective excitation. We argue that these mechanisms are robust and are therefore relevant for non-local scenarios of baryogenesis either in the Standard Model or extensions thereof.Comment: REVTeX, 19 pages, 4 eps figures, published versio

Pediatric diabetes consortium T1D New Onset ( NeOn ) study: clinical outcomes during the first year following diagnosis

Objective There have been few prospective, multicenter studies investigating the natural history of type 1 diabetes ( T1D ) from the time of diagnosis. The objective of this report from the Pediatric Diabetes Consortium ( PDC ) T1D New Onset ( NeOn ) study was to assess the natural history and clinical outcomes in children during the first year after diagnosis of T1D . Research design and methods: Clinical measures from the first year following diagnosis were analyzed for 857 participants (mean age 9.1 yr, 51% female, 66% non‐Hispanic White) not participating in an intervention study who had a HbA1c result at 12 months. Results Mean HbA1c ± SD was 102 ± 25 mmol/mol (11.4 ± 2.3%) at diagnosis, 55 ± 12 mmol/mol (7.2 ± 1.1%) at 3 months, 56 ± 15 mmol/mol (7.3 ± 1.3%) at 6 months and 62 ± 16 mmol/mol (7.8 ± 1.5%) at 12 months from diagnosis. A severe hypoglycemic ( SH ) event occurred in 31 (4%) participants (44 events, 5.2 events per 100 person‐years). Diabetic ketoacidosis ( DKA ) not including diagnosis occurred in 10 (1%) participants (13 events, 1.5 events per 100 person‐years). Conclusions After onset of T1D , mean HbA1c reaches its nadir at 3–6 months with a gradual increase through 12 months. SH and DKA are uncommon but still occur during the first year with T1D . Data from large cohorts, such as the PDC T1D NeOn study, provide important insights into the course of T1D during the first year following diagnosis, which will help to inform the development of models to target future interventions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107374/1/pedi12068.pd