The Structure and C=C Vibrational Frequencies of the all- trans Polyenes C2nH2n+2(n=2-15), C2nH2n(Me)2(n=2-13), and C2nH2n(tert-Butyl)2(n=2-5): Computational Results

Carbon-carbon bond lengths and C=C vibrational frequencies are reported for the linear, all-trans unsubstituted C2nH2n+2 (n=2-15), methyl capped C2nH2nMe2 (n=2-13), and tert-butyl capped C2nH2n(tert-butyl)2 (n=2-5) polyenes (C2h) calculated at the B3LYP/6-311++G(d,p) level. The C=C/C-C bond length alternation remains evident at this level for the unsubstituted and methyl capped polyenes as the chain length increases; the center-most difference in the length of the C-C/C=C bonds is ~0.06 Å for C30H32 and C26H26Me2. The Ag, in-phase, harmonic C=C Raman frequency for the unsubstituted polyenes decreases from 1699.2 cm-1 (n = 2) to 1528.9 cm-1 (n=15); the anharmonic frequency decreases from 1651.5 cm-1 (n = 2) to 1547.7 cm-1 (n = 8). The harmonic C=C frequency for the methyl capped polyenes decreases from 1717.9 cm-1 (n = 2) to 1539.6 cm- 1 (n= 13), and the anharmonic C=C frequency decreases from 1675.0 cm-1 (n = 2) to 1562.8 cm-1 (n = 7)

Bose-Einstein Condensation in the Relativistic Ideal Bose Gas

The Bose-Einstein condensation (BEC) critical temperature in a relativistic ideal Bose gas of identical bosons, with and without the antibosons expected to be pair-produced abundantly at sufficiently hot temperatures, is exactly calculated for all boson number-densities, all boson point rest masses, and all temperatures. The Helmholtz free energy at the critical BEC temperature is found to be lower, thus implying that the omission of antibosons always leads to the computation of a metastable state.Comment: 10 pages, 4 figure

Participatory Evaluation of Integrated Pest and Soil Fertility Management Options Using Ordered Categorical Data Analysis

During participatory rural appraisals, farmers at the Lake Victoria basin of Kenya and Uganda identified Striga, stemborer and declining soil fertility as three major constraints to maize production To reduce food insecurity, several innovative integrated technologies to address these constraints have been developed, including push-pull (maize intercropped with Desmodium and surrounded by napier grass), maize-soybean and maize-crotalaria rotations, and Imazapyrresistant (IR) maize seed coated with the herbicide. To let farmers evaluate the new technologies, 12 demonstration trials, comparing the different technologies, were established in four villages in Siaya and Vihiga districts (Western Kenya) and two villages in Busia (Uganda). These evaluations, where farmers' appreciation and feedback on the technology are captured, are an important step in technology development. During field days at the end of short rainy seasons of 2003 and 2004, 504 farmers individually observed and rated each treatment under the different cropping systems, with and without IR maize, and with and without fertilizer, with a maize continuous monocrop as control. Farmers scored each of the 16 treatments on an ordered scale of five categories: very poor, poor, average, good, and very good. The treatments were scored for each of the criteria farmers has previously determined (including yield, resistance to Striga and stemborer, and improvement of soil fertility). Analysis of the evaluation, using ordinal regression, show significant differences in farmers' preference by year and site. There was, however, little effect of farm and farmer characteristics such as farm size and gender of the observer. Ordinal regression of farmers' scores are not as intuitive and also bit cumbersome to use, but they have a better theoretical foundation than other methods, in particular the use of means. This paper shows how the method can be used, and concludes that, with some effort, it is a convenient way to analyse farmers' ranking of a large number of options.farmers' preference, technologies, ordinal regression, Crop Production/Industries,

The radial variation of HI velocity dispersions in dwarfs and spirals

Gas velocity dispersions provide important diagnostics of the forces counteracting gravity to prevent collapse of the gas. We use the 21 cm line of neutral atomic hydrogen (HI) to study HI velocity dispersion and HI phases as a function of galaxy morphology in 22 galaxies from The HI Nearby Galaxy Survey (THINGS). We stack individual HI velocity profiles and decompose them into broad and narrow Gaussian components. We study the HI velocity dispersion and the HI surface density, as a function of radius. For spirals, the velocity dispersions of the narrow and broad components decline with radius and their radial profiles are well described by an exponential function. For dwarfs, however, the profiles are much flatter. The single Gaussian dispersion profiles are, in general, flatter than those of the narrow and broad components. In most cases, the dispersion profiles in the outer disks do not drop as fast as the star formation profiles, derived in the literature. This indicates the importance of other energy sources in driving HI velocity dispersion in the outer disks. The radial surface density profiles of spirals and dwarfs are similar. The surface density profiles of the narrow component decline more steeply than those of the broad component, but not as steep as what was found previously for the molecular component. As a consequence, the surface density ratio between the narrow and broad components, an estimate of the mass ratio between cold HI and warm HI, tends to decrease with radius. On average, this ratio is lower in dwarfs than in spirals. This lack of a narrow, cold HI component in dwarfs may explain their low star formation activity.Comment: Accepted for publication in The Astronomical Journal, 13 pages, 10 figures, 4 table

The Maize Green Revolution in Kenya Revisited

The maize green revolution, which increased maize yields through the use of improved varieties and fertilizer, has stalled since the mid-eighties in Kenya. This paper examines whether the stagnation of yields continued in the 1990s in spite of the implementation of the maize liberalization policies by the Kenya Government. Analysis of farm level surveys from 1992 and 2002 indicates slight increases in the use of improved maize varieties and fertilizer, but a substantial decrease in the intensity of fertilizer use. The econometric analysis suggests that the intensity of fertilizer use has a major effect on yield. The use of improved maize varieties, however, did not affect yield, suggesting that there are local varieties for some areas that do as well as improved varieties. Research is needed to develop improved varieties for some areas, and also needed for the development of alternative affordable soil fertility measures.green revolution, maize, adoption, soil fertility, Kenya, Crop Production/Industries, International Development,

Quando o currículo se torna passarela para a diferença

Viver de múltiplas formas (n)o currículo é o tema principal deste trabalho. A partir de quatro cenas narrativas sobre desfiles de moda realizados por alunos do ensino médio numa escola pública do Recife, tecemos as linhas principais do texto buscando recompor a forma como aquelas ações coletivas habitavam o currículo de maneira singular, afetando significativamente as experiências de gênero e sexualidade daquelas pessoas. Compreendemos currículo como significante que remete a um espaço-tempo enunciativo em constante (re)formulação a partir de processos de hibridização cultural. Pontuamos a importância das interpelações subjetivas para a composição de elementos “novos” e/ou “desconhecidos” no tecido curricular e como isso pode ser entendido enquanto uma abertura desse campo à passagem da diferença, que desloca e recria os ideais de educação a partir da significação de outras vivências

A Deep 150 MHz GMRT Survey in Eridanus

We present results of a 150 MHz survey of a field centered on Epsilon Eridani, undertaken with the Giant Metrewave Radio Telescope (GMRT). The survey covers an area with a diameter of 2 deg, has a spatial resolution of 30" and a noise level of 3.1 mJy at the pointing centre. These observations provide a deeper and higher resolution view of the 150 MHz radio sky than the 7C survey (although the 7C survey covers a much larger area). A total of 113 sources were detected, most are point-like, but 20 are extended. We present an analysis of these sources, in conjunction with the NVSS (at 1.4 GHz) and VLSS (at 74 MHz). This process allowed us to identify 5 Ultra Steep Spectrum (USS) radio sources that are candidate high redshift radio galaxies (HzRGs). In addition, we have derived the dN/dS distribution for these observations and compare our results with other low frequency radio surveys.Comment: 12 pages, 11 figures, 3 tables, accepted for publication in MNRA

A thrips vector of tomato spotted wilt virus responds to tomato acylsugar chemical diversity with reduced oviposition and virus inoculation.

There is increasing evidence that acylsugars deter insect pests and plant virus vectors, including the western flower thrips (WFT), Frankliniella occidentalis (Pergande), vector of tomato spotted wilt virus (TSWV). Acylsugars are sugar-polyesters composed of saturated, un-saturated, and variously branched short and long chain fatty acids (FAs) esterified to a glucose (acylglucose) or sucrose (acylsucrose) moiety. We sought to understand how acylsucrose amount and composition of associated FA profiles interacted to mediate resistance to WFT oviposition and TSWV inoculation on tomato leaves. Towards this goal, we examined WFT oviposition and TSWV inoculation behavior on tomato lines bred to exude varying amounts of acylsucrose in association with diverse FA profiles. Our data show that as acylsucrose amounts increased, WFT egg-laying (oviposition) decreased and TSWV inoculation was suppressed. Western flower thrips also responded to FA profiles that included iC4, iC11, nC12 and nC10 FA. These findings support improving acylsugar-mediated resistance against WFT by breeding tomatoes exuding greater amounts of acylsucrose associated with specific FA profiles. We show that increasing acylsucrose amount output by type IV trichomes and selecting for particular FA profiles through advanced breeding profoundly affects WFT behavior in ways that benefit management of WFT as direct pests and as TSWV vectors

Quantization of maximally-charged slowly-moving black holes

We discuss the quantization of a system of slowly-moving extreme Reissner-Nordstrom black holes. In the near-horizon limit, this system has been shown to possess an SL(2,R) conformal symmetry. However, the Hamiltonian appears to have no well-defined ground state. This problem can be circumvented by a redefinition of the Hamiltonian due to de Alfaro, Fubini and Furlan (DFF). We apply the Faddeev-Popov quantization procedure to show that the Hamiltonian with no ground state corresponds to a gauge in which there is an obstruction at the singularities of moduli space requiring a modification of the quantization rules. The redefinition of the Hamiltonian a la DFF corresponds to a different choice of gauge. The latter is a good gauge leading to standard quantization rules. Thus, the DFF trick is a consequence of a standard gauge-fixing procedure in the case of black hole scattering.Comment: Corrected errors in the gauge-fixing procedur