Vegetation Analysis of Urban Ethnic Markets Shows Supermarket Generalists and Chinatown Ethnic-specialist Vendors

researchThe growing cultural diversity in the United States calls attention to ethnobotanical studies of urban ethnic food markets. These venues illustrate dynamic interactions between people and plants. A market survey of the Chinatown markets in Honolulu, Hawai`i was conducted to collect empirical data on this culturally rich urban area. The objectives included: (1) To analyze the food plant richness of selected Chinatown markets in comparison to local mainstream supermarkets; and (2) To test the use of vegetation analysis to describe the structure of these markets (e.g., “ethnic markets”). Surveys and mapping of food plants at three market areas in Chinatown and three mainstream supermarkets were conducted between February and March 2006. Microsoft Excel and the Community Analysis Package programs were used to analyze and compare plant richness and the structure of vendors and markets. In all of the markets combined, 291 “fresh” food plant varieties were recorded, representing 42 plant families and a group of fungi. The mainstream supermarkets were more rich in varieties of food plants than the Chinatown market area (mean ± s, 144 ± 21 vs. 95 ± 23, p=0.05, Mann-Whitney U test). Allium cepa L. and Allium sativum L. were ubiquitous. The Mainstream market group contained significantly more sweet-fruits than the Chinatown market areas. Agglomerate cluster analyses revealed groupings of mainstream supermarkets, Chinatown market areas; further analysis of the Chinatown areas defined culturally identified “Filipino,” “Vietnamese,” and specialty fruits vendors. Mainstream supermarkets may be viewed as “generalists” while the Chinatown market areas and vendors may be viewed as “specialists” for an ethnic or cultural group or food plant commodity

Infrared and Raman spectra of LiV2O5 single crystals

The phonon dynamics of LiV2O5 single crystals is studied using infrared and Raman spectroscopy techniques. The infrared-active phonon frequencies and dielectric constants are obtained by oscillator fitting procedure of the reflectivity data measured at room temperature. The Raman scattering spectra are measured at room temperature and at T=10 K in all nonequivalent polarized configurations. The assignment of the phonons is done by comparing the infrared and Raman spectra of LiV2O5 and NaV2O5. The factor-group-analysis of the LiV2O5 crystal symmetry and of its constituent layers is performed to explain the symmetry properties of the observed modes. We concluded that layer symmetry dominates in the vibrational properties of this compound.Comment: 10 pages, 5 figure

Isotropic Conductivity of Two-Dimensional Three-Component Symmetric Composites

The effective dc-conductivity problem of isotropic, two-dimensional (2D), three-component, symmetric, regular composites is considered. A simple cubic equation with one free parameter for $\sigma_{e}(\sigma_1,\sigma_2,\sigma_3)$ is suggested whose solutions automatically have all the exactly known properties of that function. Numerical calculations on four different symmetric, isotropic, 2D, three-component, regular structures show a non-universal behavior of $\sigma_{e}(\sigma_1,\sigma_2,\sigma_3)$ with an essential dependence on micro-structural details, in contrast with the analogous two-component problem. The applicability of the cubic equation to these structures is discussed. An extension of that equation to the description of other types of 2D three-component structures is suggested, including the case of random structures. Pacs: 72.15.Eb, 72.80.Tm, 61.50.AhComment: 8 pages (two columns), 8 figures. J. Phys. A - submitte

Anomalous Lattice Vibrations of Single and Few-Layer MoS2

Molybdenum disulfide (MoS2) of single and few-layer thickness was exfoliated on SiO2/Si substrate and characterized by Raman spectroscopy. The number of S-Mo-S layers of the samples was independently determined by contact-mode atomic-force microscopy. Two Raman modes, E12g and A1g, exhibited sensitive thickness dependence, with the frequency of the former decreasing and that of the latter increasing with thickness. The results provide a convenient and reliable means for determining layer thickness with atomic-level precision. The opposite direction of the frequency shifts, which cannot be explained solely by van der Waals interlayer coupling, is attributed to Coulombic interactions and possible stacking-induced changes of the intralayer bonding. This work exemplifies the evolution of structural parameters in layered materials in changing from the 3-dimensional to the 2-dimensional regime.Comment: 14 pages, 4 figure

Mechanical and Electronic Properties of MoS2_2 Nanoribbons and Their Defects

We present our study on atomic, electronic, magnetic and phonon properties of one dimensional honeycomb structure of molybdenum disulfide (MoS$_2$) using first-principles plane wave method. Calculated phonon frequencies of bare armchair nanoribbon reveal the fourth acoustic branch and indicate the stability. Force constant and in-plane stiffness calculated in the harmonic elastic deformation range signify that the MoS$_2$ nanoribbons are stiff quasi one dimensional structures, but not as strong as graphene and BN nanoribbons. Bare MoS$_2$ armchair nanoribbons are nonmagnetic, direct band gap semiconductors. Bare zigzag MoS$_2$ nanoribbons become half-metallic as a result of the (2x1) reconstruction of edge atoms and are semiconductor for minority spins, but metallic for the majority spins. Their magnetic moments and spin-polarizations at the Fermi level are reduced as a result of the passivation of edge atoms by hydrogen. The functionalization of MoS$_2$ nanoribbons by adatom adsorption and vacancy defect creation are also studied. The nonmagnetic armchair nanoribbons attain net magnetic moment depending on where the foreign atoms are adsorbed and what kind of vacancy defect is created. The magnetization of zigzag nanoribbons due to the edge states is suppressed in the presence of vacancy defects.Comment: 11 pages, 5 figures, first submitted at November 23th, 200

Oxidation and metal-insertion in molybdenite surfaces: evaluation of charge-transfer mechanisms and dynamics

Molybdenum disulfide (MoS2), a layered transition-metal dichalcogenide, has been of special importance to the research community of geochemistry, materials and environmental chemistry, and geotechnical engineering. Understanding the oxidation behavior and charge-transfer mechanisms in MoS2 is important to gain better insight into the degradation of this mineral in the environment. In addition, understanding the insertion of metals into molybdenite and evaluation of charge-transfer mechanism and dynamics is important to utilize these minerals in technological applications. Furthermore, a detailed investigation of thermal oxidation behavior and metal-insertion will provide a basis to further explore and model the mechanism of adsorption of metal ions onto geomedia

Market Survey Research: A model for ethnobotanical education

educationEthnobiological imperatives in education and NSF initiatives for improving excellence in science, technology, engineering and mathematics (STEM) education for all students were addressed by the development of a research oriented, market survey ethnobotanical project developed with the involvement of undergraduate students. This market survey project presents a model for Ethnobiological and STEM education that is adaptable to educational institutions and communities world-wide. Collaboration among users of the model and synthesis of results would provide an international look at the biocomplexity of markets systems. Students gained experience in scientific research, including: observation and forming hypothesis, collection and analysis of data, and dissemination of results. Students practiced ethnobotanical research skills, including: developing and applying an informed consent statement, producing herbarium vouchers, interacting with cultural representatives. Survey materials and hypotheses were modified during the research period to maximize our efforts. Students co-authored with instructor two publications resulting from the research involvement. The instructor gained experience by involving students in research and application of the instructor’s research to an undergraduate ethnobotanical project. Challenges are discussed, as well as recommendations synthesized from these experiences and from reviews of other student-research studies

Investigation of Unsteady/Quasi-Steady Scramjet Behavior using High-Speed Visualization Techniques

Experiments are carried out in the HEG (High Enthalpy Shock Tunnel Göttingen) wind-tunnel to obtain detailed measurements on the HyShot II scramjet configuration at equivalence ratios close to the incipient choking point at simulated 28-km altitude flight conditions. Diagnostic techniques include time-resolved pressure measurements and simultaneous high-speed schlieren and OH* chemiluminescence imaging. Similar to previous experiments at higher equivalence ratios, the onset of choking is signaled by the formation of an unsteady shock train that initially propagates up the duct. The shock motion then slows, however, and a quasi-steady topology develops with the shock lodged at a position that depends strongly on the equivalence ratio (the position lying further upstream for higher equivalence ratios). This topology persists until the conclusion of the steady test time. Based on these measurements, a value for the critical choking equivalence ratio, i.e., that at which the shock train first appears, in the range of 0.38-0.39 is determined. High-speed temperature sensitive paint measurements are also carried out on the model intake ramp to provide global information on the boundary-layer transition behavior