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The A(e,e{prime}K{sup +})YX reaction on H, D, {sup 3}He, and {sup 4}He was investigated in Hall C at CEBAF. Data were obtained for Q{sup 2} {approx} 0.35 and 0.5 GeV{sup 2} at 3.245 GeV. The missing mass spectra for both H and D are fitted with Monte-Carlo simulations incorporating peaks corresponding to {Lambda} production on the proton and {Sigma} production on both the proton and neutron. For D, the cross section ratio {Sigma}{sup 0}/{Sigma}{sup {minus}} {approx} 2, and excess yield close to the thresholds for {Lambda} and {Sigma} production can be attributed to final-state interactions that are compared to the data. The analysis of the data for the He targets is in a more preliminary state with broader quasi-free peaks resulting from the higher Fermi momenta. Evidence for bound {Lambda}-hypernuclear states is seen and other structure may be present.

A detailed investigation of the basic hyperon-nucleon interactions in nuclei is one of the aims of Experiment 91-016, approved with high priority at CEBAF, to study the electroproduction of kaons on targets of deuterium, {sup 3}He, and {sup 4}He. Inasmuch as both the electron and K{sup +} are particles that interact relatively weakly with nucleons, electroproduction of light hypernuclei provides a low-distortion method for investigating the fundamental interactions between nucleons, {Alpha}`s, and {Epsilon}`s in few-body systems. In particular, the (e,e`K{sup +}) reactions on cryogenic targets of D, {sup 3}He, and {sup 4}He will be studied at incident electron energies near 3 GeV with coincident detection of the emergent e and K{sup +} in the HMS and SOS magnetic spectrometers in Hall C. Construction of the He target, operating at {approximately}10 atm, {approximately}50 K and capable of dissipating {approximately}30 W, is expected to be complete prior to commencement of production runs in Hall C. The first data runs for E91-016, expected to begin late in FY 1995, will also be the basis for a doctoral thesis at Hampton University. In addition to providing new information on the phases of hyperon-nucleon interactions, measurements of cross sections for hypernuclear formation, and interference phenomena,more » the data may provide evidence for the presence of bound {Epsilon}`s and strange di-baryonic states that are the subject of considerable theoretical discussion.« less

A newly obtained data sample of inclusive electron-nucleon scattering from both hydrogen and deuterium targets is analyzed. These JLab data span the nucleon resonance region up to four-momentum transfers of 5 (GeV/c){sup 2} . The data are found to follow an average scaling curve. The inclusion of low-momentum transfer data yields a scaling curve resembling deep inelastic neutrino-nucleus scattering data, suggesting a sensitivity to valencelike structure only. (c) 2000 The American Physical Society.

A challenge facing America is the development of human capital, especially for the rapidly growing hospitality industry. Few studies have investigated high school students’ perceptions of hospitality careers, especially those of ethnic minorities in the US. This survey discovered significant differences between the perceptions of Anglo and minority students in Arizona. Surprisingly, although minority students often had less knowledge about hospitality jobs, they often had more interest in those jobs and in education and training programs for hospitality careers. The industry can capitalize on minority students’ interest, and enable them to pursue careers that will integrate the ranks of hospitality management.

The first measurements of the differential cross section for the d(gamma,p)n reaction up to 4.0 GeV were performed at Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. We report the cross sections at the proton center-of-mass angles of 36, 52, 69 and 89 degrees. These results are in reasonable agreement with previous measurements at lower energy. The 89 and 69 degree data show constituent-counting-rule behavior up to 4.0 GeV photon energy. The 36 and 52 degree data disagree with the counting rule behavior. The quantum chromodynamics (QCD) model of nuclear reactions involving reduced amplitudes disagrees with the present data., Comment: 5 pages (REVTeX), 1 figure (postscript)

This study surveyed employment trends in Arizona's Native American casinos and discovered that only at the level of hourly line employees do Native Americans edge out non-Native Americans. In management positions, non-Native Americans continue to outnumber Native Americans. Moreover, a recent decrease in new Native American entry-level managers bodes poorly for tribal self-management. Those trends appear to be a function of tribe size and, according to casino human-resources directors, the lack of managerial skills in most tribal populations. Human-resources officers indicated they were relatively unlikely to find qualified Native American applicants for senior and midlevel management, somewhat more likely to find qualified Native Americans for entry-level management, and considerably more likely to find them for hourly entry-level jobs. Thus all Arizona tribes need to make greater efforts, through mentoring and management-development programs, to increase substantially the numbers of Native Americans in casino management positions. The record of promoting Native Americans to management has been mixed. Of those casinos that provided opening-year versus current-year figures, Native Americans made some advances into senior-management positions since the opening of those casinos. In fact, Native Americans now outnumber non-Native Americans as senior managers at selected casinos (although not for the entire sample). At the level of hourly employees, the percentage of Native Americans has also increased. In the case of entry-level managers, however, the percentage of Native Americans has decreased, from 50 percent at opening to 39 percent today.

The (e,e'p) reaction was studies on targets of C, Fe, and Au at momentum transfers squared Q{sup 2} of 0.6, 1.3, 1.8 and 3.3 GeV{sup 2} in a region of kinematics dominated by quasifree electron-proton scattering. Missing energy and missing momentum distributions are reasonably well described by plane wave impulse approximation calculations with Q{sup 2} and A dependent corrections that measure the attenuation of the final state protons.

Mexico today is a major tourism power and its potential in resorts, ecotourism, touring, cruises, and other growing sectors of the industry is bright. But the country is threatened by mounting political, economic, and social problems which could undermine that promise. Mexico has become an increasingly unsafe place to visit. Street crime, drug trafficking, rebel activity, and government corruption have continued to grow. These threats to tourism can only be made worse by a political system in disarray. This paper examines the promise and the problems of Mexican tourism, especially problems exacerbated by political instability in this tourism dependent destination.

The A(e,e'K+)X reaction has been investigated at Jefferson Laboratory. Data were taken for Q2 {approx_equal} 0.35 GeV2 at a beam energy of 3.245 GeV for 1H,3He and 4He targets. Evidence for {lambda}-hypernuclear bound states is seen for 3,4He targets. This is the first time that the electroproduction of these hypernuclei has been observed.

Electroproduction of the {omega} meson was investigated in the {sup 1}H(e,e{sup '}p){omega} reaction. The measurement was performed at a four-momentum transfer Q{sup 2}{approx_equal}0.5 GeV{sup 2}. Angular distributions of the virtual photon-proton center-of-momentum cross sections have been extracted over the full angular range. These distributions exhibit a strong enhancement over t-channel parity exchange processes in the backward direction. According to a newly developed electroproduction model, this enhancement provides significant evidence of resonance formation in the {gamma}*p{yields}{omega}p reaction channel.

The A(e,e'K+)YX reaction has been investigated in Hall C at Jefferson Laboratory for 6 different targets. Data were taken for Q2)approx 0.35 and 0.5 GeV2) at a beam energy of 3.245GeV for 1)H, 2)H, 3)He, 4)He, C and Al targets. The missing mass spectra are fitted with Monte Carlo simulations taking into account the production of Lambda and Sigma0) hyperon production off the proton, and Sigma-) off the neutron. Models for quasifree production are compared to the data, excess yields close to threshold are attributed to FSI. Evidence for Lambda-hypernuclear bound states is seen for 3,4)He targets.

Inclusive electron scattering data are presented for ^2H, C, Fe, and Au targets at an incident electron energy of 4.045 GeV for a range of momentum transfers from Q^2=1 to 7 (GeV/c)^2. Data were taken at Jefferson Laboratory for low values of energy loss, corresponding to values of Bjorken x ≳ 1. The structure functions do not show scaling in x in this range, where inelastic scattering is not expected to dominate the cross section. The data do show scaling, however, in the Nachtmann variable ξ. This scaling appears to be the result of Bloom- Gilman duality in the nucleon structure function combined with the Fermi motion of the nucleons in the nucleus. The resulting extension of scaling to larger values of ξ opens up the possibility of accessing nuclear structure functions in the high-x region at lower values of Q^2 than previously believed.

A newly-obtained sample of inclusive electron-nucleon scattering data has been analyzed for precision tests of quark-hadron duality. The data are in the nucleon resonance region, and span the range 0.3 < Q{sup 2} < 5.0 (GeV/c){sup 2}. Duality is observed both in limited and extended regions around the prominent resonance enhancements. Higher twist contributions to the F{sub 2} structure function are found to be minimal on average, even in the low Q{sub 2} regime of approximately 0.5 (GeV/c){sup 2}. The proton magnetic form factor, extracted from purely inelastic data assuming duality, is in good agreement with the direct measurements. In all cases, duality appears to be a non-trivial property of the nucleon structure function.

A separation of the longitudinal and transverse 12 C(e, e8p) cross sections in the quasifree region has been performed in parallel kinematics at Q 2 of 0.64 and 1.8 GeV 2 for initial proton momentum ,80 MeV. The separated transverse and longitudinal spectral functions at Q 2 50.64 GeV 2 show significant differences for missing energy between 25 and 60 MeV indicating a breakdown in the single nucleon knockout picture. The transverse spectral functions exhibit definite momentum transfer dependence.

The differential cross section for ^2H(γ,d)π^0 has been measured at deuteron center-of-mass angles of 90° and 136°. This work reports the first data for this reaction above a photon energy of 1 GeV, and permits a test of the apparent constituent counting rule and reduced nuclear amplitude behavior as observed in elastic ed scattering. Measurements were performed up to a photon energy of 4.0 GeV, and are in good agreement with previous lower energy measurements. Overall, the data are inconsistent with both constituent-counting rule and reduced nuclear amplitude predictions.

Inclusive electron scattering is measured with 4.045 GeV incident beam energy from C, Fe and Au targets. The measured energy transfers and angles correspond to a kinematic range for Bjorken $x > 1$ and momentum transfers from $Q^2 = 1 - 7 (GeV/c)^2$. When analyzed in terms of the y-scaling function the data show for the first time an approach to scaling for values of the initial nucleon momenta significantly greater than the nuclear matter Fermi-momentum (i.e. $> 0.3$ GeV/c)., 5 pages TEX, 5 Postscript figures also available at http://www.krl.caltech.edu/preprints/OAP.html

We present an improved method for handling off-shell effects in deep inelastic nuclear scattering. With a firm understanding of the effects of the nuclear wave function, including these off-shell corrections as well as binding and nucleon-nucleon correlations, we can begin to examine the role of QCD in nuclei through an analysis of the moments of the nuclear structure function. Our analysis is aimed at extracting the Q^2 dependence of the moments of the nucleon structure function by using the recent high x world Iron data and by properly removing nuclear effects from the perturbative contribution. In addition, we compare quantitatively the behavior of the extracted moments with a simple O(1/Q^2) phenomenological form and we determine the mass term for this parametrization., Comment: 13 pages, 3 figures, submitted to Physics Letters B

Jefferson Lab experiment E91-013 measured the energy dependence of proton propagation in nuclei, using the quasi-free (e, e{prime}p) reaction. The ratios of the experimental (e, e{prime}p) cross-sections integrated over the quasi-free region to PWIA calculations are presented as a function of momentum transfer, (0.6 < Q{sup 2} < 3.3 GeV{sup 2}) and target nucleus (C, Fe and Au). As a first step towards a longitudinal and transverse separation of the quasi-free cross-section, a super ratio of the measured to the calculated cross-sections at forward and backward angles is presented.

The determination of appropriate space transportation technologies and operating modes is discussed with respect to both lunar and Mars missions. Three levels of activity are set forth to examine the sensitivity of transportation preferences including 'minimum,' 'full science,' and 'industrialization and settlement' categories. High-thrust-profile missions for lunar and Mars transportation are considered in terms of their relative advantages, and transportation options are defined in terms of propulsion and braking technologies. Costs and life-cycle cost estimates are prepared for the transportation preferences by using a parametric cost model, and a return-on-investment summary is given. Major technological needs for the programs are listed and include storable propulsion systems; cryogenic engines and fluids management; aerobraking; and nuclear thermal, nuclear electric, electric, and solar electric propulsion technologies.

Direct measurements confirm that the magnetized plasma perpendicular dielectric constant has a linear dependence on the plasma density for fixed magnetic field, as predicted by magnetohydrodynamic (MHD) theory. In experiments performed on the Maryland Centrifugal Experiment (MCX) [R. F. Ellis, A. B. Hassam, S. Messer, and B. R. Osborn, Phys. Plasmas, 8, 2057 (2001)], line-averaged hydrogen plasma electron density is measured using a Mach–Zehnder interferometer. For small rotational Alfven Mach numbers, the measured size of the perpendicular plasma dielectric constant is also in agreement with MHD theory. Plasma density in the range of (1–8)×1020m−3 and relative perpendicular plasma dielectric constant of the order of 106 are measured.

Partial amino acid sequences for selected amelogenin polypeptides isolated from the developing enamel of cow, pig and human foetuses are reported. It was found that there was an identity of sequence for the initial 28 residues of the polypeptides analysed, irrespective of their origin or size. A tyrosine-rich polypeptide was shown to be the N-terminal fragment of the principal higher-molecular-weight amelogenins, although a leucine-rich polypeptide of similar size was not identified in any other amelogenin structure. The findings demonstrate a striking degree of sequence conservation for the amelogenin proteins of the extracellular enamel matrix and support the concept of a discrete fragmentation of an initial 30 000 Da amelogenin molecule during the mineralization of the enamel.

A government budget in most industrial countries is a reasonably accurate statement of that government's fiscal intentions for the coming year. In less industrialized countries, however, the budget is often not a very accurate indicator of what the government will do. From the 1930s until the 1980s, the Mexican national government budgeted like a non-industrial country in certain ways. In particular, projected spending and actual spending bore little resemblance to each other. From 1933 until at least 1982, the Mexican government always spent more than it indicated in its formal budget, sometimes as much as 50 to 100 percent more. Moreover, the “excess” was spent in semi-secrecy with full public disclosure usually not occurring until years later. This paper examines the aggregate pattern of this budgetary gap and its strategic use by Mexican presidents.

Gelatin-binding material was isolated from a human plasma cryoprecipitate by affinity chromatography on gelatin-Sepharose. Individual fragments of fibronectin with Mr = 170,000, 100,000, and 80,000 and a mixture of fragments with Mr = 205,000 and 190,000 (200K fraction) were isolated from this material. These fragments reacted with antifibronectin and with antibodies to a gelatin-binding Mr = 70,000 tryptic fragment of fibronectin. They all shared the same NH2-terminal amino acid sequence. The 205K and 190K fragments bound also to heparin-Sepharose, whereas the smaller fragments did not. The 200K fraction and the 170K fragment mediated cell attachment when used to coat plastic, whereas the 100K and 80K fragments were inactive in this assay. Further digestion of the 205K and 190K fragments with chymotrypsin yielded separate sets of smaller fragments that bound to either gelatin-Sepharose or heparin-Sepharose, as well as fragments that did not show either of these binding activities but mediated cell attachment. Since the NH2-terminal ends of the 205K, 190K, 100K, and 80K fragments are the same, the results define the order of the active sites in the fibronectin molecule as gelatin-binding site, cell attachment site, and heparin-binding site.

The Negro protest against segregated public ac commodations and facilities is a reform social movement which seeks total desegregation of all facets of American life. The protest is analyzed in terms of ideology, tactics and strategy, leadership, and membership. Basic conclusions are that, al though nonviolent direct action was a successful means of mass nonco-operation with segregation, tactics were dictated by ex pediency and not by a master plan of strategy; that protest organizations conflict over tactics and credit; that biracial com mittees have become an important tactic for diminishing racial tension; that all social classes are potential sources of members for protest organizations; and that Negro leaders no longer re quire white support. While the Civil Rights Act altered the structural basis of segregation, programs to improve the indi vidual Negro are needed. Changes in the race relations pattern depend upon interracial communication, leadership unity in the white versus the Negro community, the willingness of Negroes to protest, and the racial climate within the community.

When racial status becomes an uncontrollable obstacle to social mobility, one important reaction is hostility toward the dominant group. Since overt hostility is severely punished in the South, it must often be covert. From this level, it gains one avenue of expression in the Negro conceptions of white people. These data reveal that lower-class Negroes are more unfavorable in their stereotyped conceptions of white people than either the middle or the upper classes and that middle-class Negroes possess the most favorable conceptions.

Gelatin-binding material was isolated from a human plasma cryoprecipitate by affinity chromatography on gelatin-Sepharose. Individual fragments of fibronectin with Mr = 170,000, 100,000, and 80,000 and a mixture of fragments with Mr = 205,000 and 190,000 (200K fraction) were isolated from this material. These fragments reacted with antifibronectin and with antibodies to a gelatin-binding Mr = 70,000 tryptic fragment of fibronectin. They all shared the same NH2-terminal amino acid sequence. The 205K and 190K fragments bound also to heparin-Sepharose, whereas the smaller fragments did not. The 200K fraction and the 170K fragment mediated cell attachment when used to coat plastic, whereas the 100K and 80K fragments were inactive in this assay. Further digestion of the 205K and 190K fragments with chymotrypsin yielded separate sets of smaller fragments that bound to either gelatin-Sepharose or heparin-Sepharose, as well as fragments that did not show either of these binding activities but mediated cell attachment. Since the NH2-terminal ends of the 205K, 190K, 100K, and 80K fragments are the same, the results define the order of the active sites in the fibronectin molecule as gelatin-binding site, cell attachment site, and heparin-binding site.

The amino acid sequences of a leucine-rich amelogenin polypeptide (LRAP) and a tyrosine-rich amelogenin polypeptide (TRAP), isolated from foetal bovine enamel matrix, were determined. Both LRAP and TRAP occurred in two forms; in each case, one of the molecular species appeared to be shortened at the COOH terminus by 2 and 4 residues, respectively. A striking finding was that LRAP and TRAP had identical sequences for the first 33 residues but were almost completely different for the remaining 12 amino acids.

The first measurements of differential cross sections for deuteron photo-disintegration at photon energies up to 4 GeV were performed at the Thomas Jefferson National Accelerator Facility early in 1996. Cross section results for D(γ,p)n at proton center of mass angle of 35°, 53° and 90° will be presented. These results are in good agreement with previous measurements at low energy and extend to higher energies where data were previously unavailable. The 90° degree data show behavior consistent with the constituent counting rules up to 4 GeV and are also in fair agreement with the asymptotic meson exchange model. The 37° and 53° data do not show clear signs of counting rule behavior, although a threshold in transverse momentum for the onset of scaling cannot be excluded.

During the past ten Oears, the changing character of the Negro's relative and absolute suffrage status in Arkansas has been possibly greater than at any comparable period since Emancipation. The various factors involved in the problem of Negro suffrage expansion are an integral part of the overt political, social, and economic structures and the covert or psychological correlates of the dynamic racial power system.' In race relations, differential social power carries unequal access to the opportunities and rewards of society serving both as a determinant and as a consequence2 of unequal power distribution. While it is likely that some power inequalities characterize every group relationship, the political structure emerges from the unique set of socio-economic factors which underlie the historical development of the society. Thus, this treatment of the suffrage status of 'the Arkansas Negro describes the inequality of political power within the complex system of Negro-white group relationships. We shall delineate specifically in this paper Negro and white socio-cultural'and