The Strangeness Physics Program at CLAS

An extensive program of strange particle production off the proton is currently underway with the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at Jefferson Laboratory. This talk will emphasize strangeness photo- and electroproduction in the baryon resonance region between W =1.6 and 2.5 GeV, where indications of s-channel structure are suggestive of high-mass baryon resonances coupling to kaons and hyperons in the final state. Precision measurements of cross sections and polarization observables are being carried out with both electron and real photon beams, both of which are available with high polarization at energies up to 6 GeV.Comment: 10 pages, 6 figures, N*2005 Conferenc

Experimental Evidence for the Pentaquark

The present experimental evidence for the existence of light pentaquarks is reviewed, including both positive and null results. I also discuss the CLAS experiments at Jefferson Laboratory that are forthcoming in the near future to address questions regarding existence, mass, width, and other quantum numbers of these five-quark baryon states.Comment: 6 pages, 5 figures, Electron-Nucleus Scattering VIII conferenc

Experimental L-band SST satellite communications/surveillance terminal study. Volume 4 - Aircraft antenna studies

Antenna requirements for supersonic transport satellite communications syste

Predictions of the emergence of vaccine-resistant hepatitis B in The Gambia using a mathematical model

Vaccine escape variants of hepatitis B virus (HBV) have been identified world-wide. A mathematical model of HBV transmission is used to investigate the potential pattern of emergence of such variants. Attention is focused on The Gambia as a country with high quality epidemiological data, universal infant immunization and in which escape mutants after childhood infections have been observed. We predict that a variant cannot become dominant for at least 20 years from the start of vaccination, even when using a vaccine which affords no cross protection. The dominant factor responsible for this long time scale is the low rate of infectious contacts between infected and susceptible individuals (we estimate the basic reproduction number of hepatitis B in The Gambia to be 1·7). A variant strain that achieves high prevalence will also take many years to control, and it is questionable whether emergence will be identifiable by sero-surveillance until of high prevalence. The sensitivity of the model predictions to epidemiological and demographic factors is explored

SOME EMPIRICAL METHODS OF ESTIMATING ADVERTISING EFFECTS IN DEMAND SYSTEMS: AN APPLICATION TO DRIED FRUITS

Two different methods of incorporating advertising effects into Almost Ideal Demand Systems (AIDS) are presented. Both advertising schemes are designed to allow theoretical restrictions to hold globally rather than at particular sample points. The models are estimated for California figs, prunes, and raisins. Empirical results indicate that generic advertising effects for these three dried fruits are generally weak when compared to price and total expenditure effects. Estimated cross-commodity effects also are relatively small except for the negative effect of raisin advertising on the quantity of prunes demanded.Demand and Price Analysis, Marketing,

Predictions of the emergence of vaccine-resistant hepatitis B in The Gambia using a mathematical model

Vaccine escape variants of hepatitis B virus (HBV) have been identified world-wide. A mathematical model of HBV transmission is used to investigate the potential pattern of emergence of such variants. Attention is focused on The Gambia as a country with high quality epidemiological data, universal infant immunization and in which escape mutants after childhood infections have been observed. We predict that a variant cannot become dominant for at least 20 years from the start of vaccination, even when using a vaccine which affords no cross protection. The dominant factor responsible for this long time scale is the low rate of infectious contacts between infected and susceptible individuals (we estimate the basic reproduction number of hepatitis B in The Gambia to be 1·7). A variant strain that achieves high prevalence will also take many years to control, and it is questionable whether emergence will be identifiable by sero-surveillance until of high prevalence. The sensitivity of the model predictions to epidemiological and demographic factors is explored

Experimental Status of Exotic Mesons and the GlueX Experiment

One of the unanswered and most fundamental questions in physics regards the nature of the confinement mechanism of quarks and gluons in QCD. Exotic hybrid mesons manifest gluonic degrees of freedom and their spectroscopy will provide the data necessary to test assumptions in lattice QCD and the specific phenomenology leading to confinement. Within the past two decades a number of experiments have put forth tantalizing evidence for the existence of exotic hybrid mesons in the mass range below 2 GeV. This talk represents an overview of the available data and what has been learned. In looking toward the future, the GlueX experiment at Jefferson Laboratory represents a new initiative that will perform detailed spectroscopy of the light-quark meson spectrum. This experiment and its capabilities will be reviewed.Comment: 10 pages, 8 figures, 2nd Meeting of the APS Topical Group on Hadron Physics GHP06, Nashville, TN (10/22-10/24/06

Study of continuum nuclear structure of 12C via (p,p'X) at intermediate energies

The inclusive 12C(p,p') and exclusive 12C(p,p'X) reactions have been studied with a beam energy of 156 MeV and for X = p and alpha. The study focuses on the (p,p'X) reaction mechanism and on the structure of 12C just above the particle-emission threshold, 14 < E_x < 28 MeV. Cross sections were simultaneously measured for all three reactions. The exclusive data were analyzed by making multiple-peak fits of the spectra and by Legendre-polynomial fits of the angular correlations. Multiple-peak fits were also made of the inclusive spectra. The resultant cross sections were compared to theoretical calculations. An analysis of the results shows that this region of E_x consists predominantly of resonant excitations, in contradiction to the findings of previous analyses.Comment: 12 pages, 4 figures, elsart style files, submitted to Physics Letters

Tingkah Laku Memijah, Potensi Reproduksi Ikan Betina, dan Optimasi Teknik Pemijahan Ikan Pelangi Iriatherina Werneri Meinken, 1974 [Spawning Behavior, Female Reproductive Potential And Breeding Technique Optimize Of Threadfin Rainbowfish...............

Informasi reproduksi ikan pelangi Iriatherina werneri pada wadah terkontrol masih sedikit diketahui. Oleh karena itu, diperlukan kajian mengenai tingkah laku memijah, potensi reproduksi ikan betina berdasarkan perbedaan pakan (buatan dan alami), dan optimasi teknik pemijahan. Kajian optimasi pemijahan meliputi pengamatan pengaruh perbedaan sistem pemijahan (massal atau individual), perbedaan rasio kelamin pemijahan jantan : betina (1:1, 1:2, dan 1:3), serta perbedaan ukuran betina (kecil, sedang, dan besar) untuk mendukung kegiatan budi daya. Hasil penelitian menunjukkan bah-wa pemijahan ikan pelangi terjadi pada 13-15 jam sejak pemasangan ikan jantan dan betina yang diawali oleh gerakan ikan jantan mengembangkan dan menguncupkan sirip. Telur yang dikeluarkan pada pemijahan massal berakhir dua jam lebih cepat dibandingkan pemijahan individual dan telur lebih serempak dikeluarkan pagi hari (94,92%). Ikan pelangi merupakan pemijah bertahap yang mampu memijah setiap hari selama 30 hari. Potensi jumlah telur dan larva yang di-hasilkan seekor betina dapat ditingkatkan masing-masing sebanyak empat kali lipat dan 14 kali lipat melalui pemberian pakan alami. Optimasi teknik pemijahan I. werneri dicapai dengan menggunakan sistem massal dengan rasio kelamin 1: 3 dan menggunakan ikan betina berukuran 26,98-35,76 mm