Dynamical Supersymmetry Breaking and Low Energy Gauge Mediation

Dynamical breaking of supersymmetry was long thought to be an exceptional phenomenon, but recent developments have altered this view. A question of great interest in the current framework is the value of the underlying scale of supersymmetry breaking. The "little hierarchy" problem suggests that supersymmetry should be broken at low energies. Within one class of models, low energy breaking be achieved as a consequence of symmetries, without requiring odd coincidences. The low energy theories are distinguished by the presence or absence of $R$ symmetries; in either case, and especially the latter one often finds modifications of the minimal gauge-mediated spectrum which can further ameliorate problems of fine tuning. Various natural mechanisms exist to solve the $\mu$ problem in this framework.Comment: 20 pages (minor change in referencing

NUE: Nano Science And Laboratory Experience (ScALE) at UMaine

This Nanotechnology Undergraduate Education (NUE) in Engineering program entitled, NUE: Nano Science And Laboratory Experience (ScALE) at UMaine , at the University of Maine, under the direction of Dr. Rosemary L. Smith, aims to introduce the basic concepts, applications, and implications of nanoscale science and engineering to all first-year engineering students at the University of Maine (UMaine). The proposed approach is to add nanoscience and nanoscale engineering content to the required \u27introduction to\u27 engineering courses offered by each engineering department. This content will be designed, developed and delivered as a \u27drop-in\u27 module, in collaboration with the instructors for each department\u27s course. This project further aims to enhance undergraduate education and training in nanoscale science and engineering by establishing a college-wide minor in Nanotechnology, developing an upper level course in nanoscience, and to broaden participation of 1st and 2nd year students from underrepresented groups in nanoscale research. The broader impacts of this project include improved student recruitment, retention, and future workforce preparation achieved through the intentional integration of research and education at the undergraduate level, professional development of Maine\u27s middle-school science teachers, the facilitation of new research and education collaborations among UMaine faculty with interests in nanoscale science and engineering, and the sharing of state-of-the-art instructional tools such as laboratory facilities and materials. Outreach activities will focus on increasing the interest of female students in engineering careers by developing mini-projects for high school students targeting nanotechnology applications to biomedicine and energy

MRI: ID-Development of a Hybrid Scanning Fluorescence and Sum Frequency Spectroscopy Imaging Microscope

With this award from the Major Research Instrumentation program (MRI), Michael Mason and colleagues from the Department of Chemistry at the University of Maine will develop a hybrid scanning fluorescence (FL) and sum frequency (SF) spectroscopy imaging microscope. The instrument will be constructed by the addition of sample scanning and FL capability to an existing broadband SF spectrometer. The SF NIR pump source will be used to excite SF at the sample interface, while a modulated Argon ion CW laser will excite FL. These collinear sources will give rise to spatially and temporally correlated SF and FL signals which will be separated and individually detected. The instrument will simultaneously measure the fluorescence and sum frequency to yield information about the localized dynamics of a single particle, i.e. protein, and spatially correlated structural information about the bulk material containing the particle. This yields information about the interaction between the particle and the bulk not accessible by any other method. The proposal will initially investigate test projects including the study of membrane domain structure and membrane-membrane interactions, e,g., correlation of the structure and dynamics of lipid and protein molecules within planar supported lipid bilayers. Successful development of this instrument could lead to major breakthroughs in several fields ranging from surface chemistry and biophysics to nanotechnology and cellular biology

Elevated aggrecan mRNA in early murine osteoarthritis

SummaryMale STR/ort mice develop osteoarthritis in the tibial articular cartilage. Low grade histological lesions first appear between 10–20 weeks of age. A previous study showed that the level of aggrecan, the major cartilage proteoglycan, is approximately twofold greater in the tibial cartilage of 16–19-week-old STR/ort mice compared with that in normal cartilage in control CBA mice. In the present investigation aggrecan gene transcription was investigated in 20-week-old STR/ort and CBA tibial cartilage using a quantitative reverse transcription-polymerase chain reaction (RT-PCR). The amount of aggrecan cDNA obtained from the STR/ort medial and lateral plateau was 2.8- and 4.6-fold greater per milligram of wet cartilage than that from the CBA tibial plateau. The difference was not due to differences in cellularity of tibial cartilage in the two strains and indicates that aggrecan gene transcription is elevated in early osteoarthritis

Foreground Predictions for the Cosmic Microwave Background Power Spectrum from Measurements of Faint Inverted Radio Sources at 5 GHz

We present measurements of a population of matched radio sources at 1.4 and 5 GHz down to a flux limit of 1.5 mJy in 7 sq. degs. of the NOAO Deep Field South. We find a significant fraction of sources with inverted spectral indices that all have 1.4 GHz fluxes less than 10 mJy, and are therefore too faint to have been detected and included in previous radio source count models that are matched at multiple frequencies. Combined with the matched source population at 1.4 and 5 GHz in 1 sq. deg. in the ATESP survey, we update models for the 5 GHz differential number counts and distributions of spectral indices in 5 GHz flux bins that can be used to estimate the unresolved point source contribution to the cosmic microwave background temperature anisotropies. We find a shallower logarithmic slope in the 5 GHz differential counts than in previously published models for fluxes < 100 mJy as well as larger fractions of inverted spectral indices at these fluxes. Because the Planck flux limit for resolved sources is larger than 100 mJy in all channels, our modified number counts yield at most a 10% change in the predicted Poisson contribution to the Planck temperature power spectrum. For a flux cut of 5 mJy with the South Pole Telescope and a flux cut of 20 mJy with the Atacama Cosmology Telescope we predict a ~30% and ~10% increase, respectively, in the radio source Poisson power in the lowest frequency channels of each experiment relative to that predicted by previous models.Comment: 14 pages, 9 figures, includes ApJ proof correction

Crossover and scaling in a two-dimensional field-tuned superconductor

Using an analysis similar to that of Imry and Wortis, it is shown that the apparent first order superconductor to metal transition, which has been claimed to exist at low values of the magnetic field in a two-dimensional field-tuned system at zero temperature,can be consistentlyinterpreted as a sharp crossover from a strong superconductor to an inhomogeneous state, which is a weak superconductor. The true zero-temperature superconductor to insulator transition within the inhomogenous state is conjectured to be that of randomly diluted XY model. An explaination of the observed finite temperature approximate scaling of resistivity close to the critical point is speculated within this model.Comment: 5 pages, 2 figures, corrected and modified according to referee Report

Supersymmetry and Its Dynamical Breaking

Abstract This article reviews the subject of supersymmetry and its breaking. The emphasis is on recent developments in metastable, dynamical supersymmetry breaking, which permit the construction of promising models of particle physics

Genus Two Partition and Correlation Functions for Fermionic Vertex Operator Superalgebras I

We define the partition and $n$-point correlation functions for a vertex operator superalgebra on a genus two Riemann surface formed by sewing two tori together. For the free fermion vertex operator superalgebra we obtain a closed formula for the genus two continuous orbifold partition function in terms of an infinite dimensional determinant with entries arising from torus Szeg\"o kernels. We prove that the partition function is holomorphic in the sewing parameters on a given suitable domain and describe its modular properties. Using the bosonized formalism, a new genus two Jacobi product identity is described for the Riemann theta series. We compute and discuss the modular properties of the generating function for all $n$-point functions in terms of a genus two Szeg\"o kernel determinant. We also show that the Virasoro vector one point function satisfies a genus two Ward identity.Comment: A number of typos have been corrected, 39 pages. To appear in Commun. Math. Phy