Energy Dependence of the Delta Resonance: Chiral Dynamics in Action

There is an important connection between the low energy theorems of QCD and the energy dependence of the Delta resonance in pi-N scattering, as well as the closely related gamma^{*} N -> pi N reaction. The resonance shape is due not only to the strong pi-N interaction in the p wave but the small interaction in the s wave; the latter is due to spontaneous chiral symmetry breaking in QCD (i.e. the Nambu-Goldstone nature of the pion). A brief overview of experimental tests of chiral perturbation theory and chiral based models is presentedComment: 11 pages, 6 figures, Festschrift for S.N. yan

Farmers’ knowledge of the banana (Musa Sp.) agroforestry systems in Kiboga District, Central Uganda

Banana is a major food and cash crop in Uganda, particularly in the central and southwestern regions. However, production is still below attainable yields and at the same time declining due to a number of reasons, with low soil fertility being paramount. Few farmers use inorganic fertilizers, with majority of them relying mainly on organic supplements including integration of trees/shrubs. However, trees and shrubs exist on banana farms in undefined numbers and composition, with no spacing and canopy management recommendations. Also, there is limited information on farmers’ knowledge on these systems. A survey was, therefore, conducted on 70 randomly selected farms in Kiboga district, central Uganda to assess farmers’ knowledge of, as well as identify trees and shrubs species and banana cultivars in their agro-ecologies. A total of 1,558 trees and shrubs belonging to 40 species and 21 families were recorded in the study area (52 trees/shrubs per banana plantation). These were dominated by Jackfruit, Artocarpus heterophyllus (15%), Natal fig, Ficus natalensis (10%), Albizia, Albizia coriaria (10%) and mango, Mangifera indica (9%). Further, 1,779 banana mats belonging to nine (9) cultivars and three (3) genome groups were observed growing underneath these four commonest tree species (2.6 banana mats per tree). The highest number of banana mats was observed growing underneath F. natalensis (54%) and A. coriaria (42%). Most (87%) observed banana cultivars belonged to the cooking East African Highland Banana (Musa AAA-EAHB) and dominated by Ndibwabalangira (21%). Farmers reported 25 benefits they derive from banana-trees/shrubs integration; with shade and firewood (38%), as well as income and timber (35%) being the main benefits reported. They also reported that the highest percentage of benefits was derived from F. natalensis (44%) and A. coriaria (32%). Of the four (4) most prevalent tree species, A. coriaria (100%) and F. natalensis (96%) were reported as good companion plant to bananas, whereas, A. heterophyllus (99%) and M. indica (97%) were regarded as bad companion plants. Farmers preferred a tree that allows light penetration (96%), is compatible with bananas and other crops (87%) and has easily decomposable leaves (83%). Therefore, F. natalensis and A. coriaria should be integrated in banana agrosystems for soil fertility improvement whereas; A. heterophyllus and M. indica be planted on farm boundaries. However, the best-bet spacing and pruning regimes for these trees should be determined to minimize the negative attributes as much as possible.Keywords: Albizia coriaria, Artocarpus heterophyllus, banana cultivars, benefits, companions, Ficus natalensis, Mangifera indica, tree-specie

New Measurement of Compton Scattering from the Deuteron and an Improved Extraction of the Neutron Electromagnetic Polarizabilities

The electromagnetic polarizabilities of the nucleon are fundamental properties that describe its response to external electric and magnetic fields. They can be extracted from Compton-scattering data --- and have been, with good accuracy, in the case of the proton. In contradistinction, information for the neutron requires the use of Compton scattering from nuclear targets. Here we report a new measurement of elastic photon scattering from deuterium using quasimonoenergetic tagged photons at the MAX IV Laboratory in Lund, Sweden. These first new data in more than a decade effectively double the world dataset. Their energy range overlaps with previous experiments and extends it by 20 MeV to higher energies. An analysis using Chiral Effective Field Theory with dynamical \Delta(1232) degrees of freedom shows the data are consistent with and within the world dataset. After demonstrating that the fit is consistent with the Baldin sum rule, extracting values for the isoscalar nucleon polarizabilities and combining them with a recent result for the proton, we obtain the neutron polarizabilities as \alpha_n = [11.55 +/- 1.25(stat) +/- 0.2(BSR) +/- 0.8(th)] X 10^{-4} fm^3 and \beta_n = [3.65 -/+ 1.25(stat) +/- 0.2(BSR) -/+ 0.8(th)] X 10^{-4} fm3, with \chi^2 = 45.2 for 44 degrees of freedom.Comment: 6 pages, 3 figures, comments from Physical Review Letters Referees addresse

An Optical Readout TPC (O-TPC) for Studies in Nuclear Astrophysics With Gamma-Ray Beams at HIgS

We report on the construction, tests, calibrations and commissioning of an Optical Readout Time Projection Chamber (O-TPC) detector operating with a CO2(80%) + N2(20%) gas mixture at 100 and 150 Torr. It was designed to measure the cross sections of several key nuclear reactions involved in stellar evolution. In particular, a study of the rate of formation of oxygen and carbon during the process of helium burning will be performed by exposing the chamber gas to intense nearly mono-energetic gamma-ray beams at the High Intensity Gamma Source (HIgS) facility. The O-TPC has a sensitive target-drift volume of 30x30x21 cm^3. Ionization electrons drift towards a double parallel grid avalanche multiplier, yielding charge multiplication and light emission. Avalanche induced photons from N2 emission are collected, intensified and recorded with a Charge Coupled Device (CCD) camera, providing two-dimensional track images. The event's time projection (third coordinate) and the deposited energy are recorded by photomultipliers and by the TPC charge-signal, respectively. A dedicated VME-based data acquisition system and associated data analysis tools were developed to record and analyze these data. The O-TPC has been tested and calibrated with 3.183 MeV alpha-particles emitted by a 148Gd source placed within its volume with a measured energy resolution of 3.0%. Tracks of alpha and 12C particles from the dissociation of 16O and of three alpha-particles from the dissociation of 12C have been measured during initial in-beam test experiments performed at the HIgS facility at Duke University. The full detection system and its performance are described and the results of the preliminary in-beam test experiments are reported.Comment: Supported by the Richard F. Goodman Yale-Weizmann Exchange Program, ACWIS, NY, and USDOE grant Numbers: DE-FG02-94ER40870 and DE-FG02-97ER4103

Heterogeneity of CYP3A isoforms metabolizing erythromycin and cortisol

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109905/1/cptclpt19923.pd

Unitary Isobar Model - MAID2007

The unitary isobar model MAID2007 has been developed to analyze the world data of pion photo- and electroproduction. The model contains both a common background and several resonance terms. The background is unitarized according to the K-matrix prescription, and the 13 four-star resonances with masses below 2 GeV are described by appropriately unitarized Breit-Wigner forms. The data have been analyzed by both single-energy and global fits, and the transverse and longitudinal helicity amplitudes have been extracted for the four-star resonances below 2 GeV. Because of its inherent simplicity, MAID2007 is well adopted for predictions and analysis of the observables in pion photo- and electroproduction.Comment: 32 pages including 13 tables and 24 figure

Measurements of the \gamma * p --> \Delta(1232) reaction at low Q2

We report new p$(\vec{e},e^\prime p)\pi^\circ$ measurements in the $\Delta^{+}(1232)$ resonance at the low momentum transfer region utilizing the magnetic spectrometers of the A1 Collaboration at MAMI. The mesonic cloud dynamics are predicted to be dominant and appreciably changing in this region while the momentum transfer is sufficiently low to be able to test chiral effective calculations. The results disagree with predictions of constituent quark models and are in reasonable agreement with dynamical calculations with pion cloud effects, chiral effective field theory and lattice calculations. The reported measurements suggest that improvement is required to the theoretical calculations and provide valuable input that will allow their refinements