Clustering of the Diffuse Infrared Light from the COBE DIRBE maps. III. Power spectrum analysis and excess isotropic component of fluctuations

The cosmic infrared background (CIB) radiation is the cosmic repository for energy release throughout the history of the universe. Using the all-sky data from the COBE DIRBE instrument at wavelengths 1.25 - 100 mic we attempt to measure the CIB fluctuations. In the near-IR, foreground emission is dominated by small scale structure due to stars in the Galaxy. There we find a strong correlation between the amplitude of the fluctuations and Galactic latitude after removing bright foreground stars. Using data outside the Galactic plane ($|b| > 20\deg$) and away from the center ($90\deg< l <270\deg$) we extrapolate the amplitude of the fluctuations to cosec$|b|=0$. We find a positive intercept of $\delta F_{\rm rms} = 15.5^{+3.7}_{-7.0},5.9^{+1.6}_{-3.7}, 2.4^{+0.5}_{-0.9}, 2.0^{+0.25}_{-0.5}$ nW/m2/sr at 1.25, 2.2,3.5 and 4.9 mic respectively, where the errors are the range of 92% confidence limits. For color subtracted maps between band 1 and 2 we find the isotropic part of the fluctuations at $7.6^{+1.2}_{-2.4}$ nW/m2/sr. Based on detailed numerical and analytic models, this residual is not likely to originate from the Galaxy, our clipping algorithm, or instrumental noise. We demonstrate that the residuals from the fit used in the extrapolation are distributed isotropically and suggest that this extra variance may result from structure in the CIB. For 2\deg< \theta < 15^\deg, a power-spectrum analysis yields firm upper limits of (\theta/5^\deg) \times\delta F_{\rm rms} (\theta) < 6, 2.5, 0.8, 0.5 nW/m2/sr at 1.25, 2.2, 3.5 and 4.9 mic respectively. From 10-100 mic, the upper limits <1 nW/m2/sr.Comment: Ap.J., in press. 69 pages including 24 fig

Mid-Infrared Emission from E+A Galaxies in the Coma Cluster

We have used ISO to observe at 12$\mu$m seven E+A galaxies plus an additional emission line galaxy, all in the Coma cluster. E+A galaxies lacking narrow emission lines have 2.2$\mu$m to 12$\mu$m flux density ratios or limits similar to old stellar populations (typical of early-type galaxies). Only galaxies with emission lines have enhanced 12$\mu$m flux density. Excess 12$\mu$m emission is therefore correlated with the presence of on-going star formation or an active galactic nucleus (AGN). By comparing the current star formation rates with previous rates estimated from the Balmer absorption features, we divide the galaxies into two groups: those for which star formation has declined significantly following a dramatic peak $\sim$ 1 Gyr ago; and those with a significant level of ongoing star formation or/and an AGN. There is no strong difference in the spatial distribution on the sky between these two groups. However, the first group has systemic velocities above the mean cluster value and the second group below that value. This suggests that the two groups differ kinematically. Based on surveys of the Coma cluster in the radio, the IRAS sources, and galaxies detected in H$\alpha$ emission, we sum the far infrared luminosity function of galaxies in the cluster. We find that star formation in late type galaxies is probably the dominant component of the Coma cluster far infrared luminosity. The presence of significant emission from intracluster dust is not yet firmly established. The member galaxies also account for most of the far infrared output from nearby rich clusters in general.Comment: AAS Latex, accepted for publication in Ap

Optimal Renormalization-Group Improvement of R(s) via the Method of Characteristics

We discuss the application of the method of characteristics to the renormalization-group equation for the perturbative QCD series within the electron-positron annihilation cross-section. We demonstrate how one such renormalization-group improvement of this series is equivalent to a closed-form summation of the first four towers of renormalization-group accessible logarithms to all orders of perturbation theory

The Gas Phase in a Low Metallicity ISM

Original article can be found at: http://journals.cambridge.org/ Copyright International Astronomical Union. DOI: 10.1017/S1743921308024927We present several results from our analysis of dwarf irregular galaxies culled from The HI Nearby Galaxy Survey (THINGS). We analyse the rotation curves of two galaxies based on “bulk” velocity fields, i.e. velocity maps from which random non–circular motions are removed. We confirm that their dark matter distribution is best fit by an isothermal halo model. We show that the star formation properties of dIrr galaxies resemble those of the outer parts of larger, spiral systems. Lastly, we study the large scale (3–D) distribution of the gas, and argue that the gas disk in dIrrs is thick, both in a relative, as well as in an absolute sense as compared to spirals. Massive star formation through subsequent supernova explosions is able to redistribute the bulk of the ISM, creating large cavities. These cavities are often larger, and longer–lived than in spiral galaxies.Peer reviewe

Hecke algebras with unequal parameters and Vogan's left cell invariants

In 1979, Vogan introduced a generalised $\\tau$ -invariant for characterising primitive ideals in enveloping algebras. Via a known dictionary this translates to an invariant of left cells in the sense of Kazhdan and Lusztig. Although it is not a complete invariant, it is extremely useful in describing left cells. Here, we propose a general framework for defining such invariants which also applies to Hecke algebras with unequal parameters.Comment: 15 pages. arXiv admin note: substantial text overlap with arXiv:1405.573

Density functional investigations of defect induced mid-gap states in graphane

We have carried out ab initio electronic structure calculations on graphane (hydrogenated graphene) with single and double vacancy defects. Our analysis of the density of states reveal that such vacancies induce the mid gap states and modify the band gap. The induced states are due to the unpaired electrons on carbon atoms. Interestingly the placement and the number of such states is found to be sensitive to the distance between the vacancies. Furthermore we also found that in most of the cases the vacancies induce a local magnetic moment.Comment: 15 page

Surface Tension, Interfacial Tension and Phase Behavior: Interactions of Surfactant/Polymer Solutions with Crude Oil

Advanced oil recovery techniques, beyond primary and secondary recovery, are required in order to produce additional oil in existing reservoir rock. Here, we evaluated a combination of polymer and surfactant aqueous solutions, in order to generate a working fluid capable of achieving high-performance enhanced oil recovery (EOR). In this recovery process, surfactant is added to the water flooding mixture in order to lower the interfacial tension between the oil and the water. If the interfacial tension can be decreased by ~1,000-fold, then the aqueous solution can mobilize and displace the oil. Moreover, a polymer is added to the aqueous solution in order to increase the viscosity of the working fluid. Aqueous solutions with a viscosity higher than the oil viscosity can produce a stable flow of oil. However, the exact combination and concentration needed for these two key components to be effective is dependent on each oil reservoir and requires several experiments and specific tuning in order to yield an effective design. In order to determine the optimal combination, the effects of the average molecular weight of the polymers, the surfactant chemistry, and their combinations in salt solutions (at varying salt concentrations) were investigated. Specifically, the surface tension of aqueous solutions against air and the interfacial tension against oil and the phase behavior of the polymer-surfactant systems were evaluated with a model hydrocarbon, dodecane, and with crude oil. By varying the molecular properties of the surfactant and the polymer, we found a technically promising surfactant-polymer combination for potential EOR application

Participatory Evaluation and Selection of Improved \u3ci\u3eUrochloa\u3c/i\u3e Grass Cultivars in Kenya

Low adoption of superior agricultural technologies has been attributed to insufficient attention given to farmers’ priorities and perceptions while developing technologies. There is therefore a need to involve farmers in development of new forage technologies in order to increase adoption. Participatory variety selection (PVS) was conducted on eight Urochloa grass cultivars in the coastal lowlands, eastern midlands, central highlands and northwestern highlands of Kenya to select cultivars that are more adaptable in each region. The eight Urochloa cultivars; U. brizantha cvs. Marandu, Xaraes, Piatã, MG4, U. decumbens cv. Basilisk, U. humidicola cvs. Llanero and Humidicola, and U. hybrid cv. Mulato II were evaluated against cultivated local grasses; Rhodes grass (Chloris gayana cv. KATR3) and Napier grass (Pennisetum purpureum cv. Kakamega 1). In each region, farmers were engaged in development of selection criteria through focus group discussions. For each criterion, farmers’ scored on individual grass cultivars using a Likert scale of 1 to 4 with higher scores indicating high cultivar preference. Farmers considered 12 to17 plant attributes in the selection of the most suitable forages for planting. The attributes included plant height, colour, spread, biomass among others. MG4 was the most preferred Urochloa cultivar in eastern midlands, central and northwestern highlands while Mulato II was most preferred in coastal lowlands. The study concluded that, the selected Urochloa cultivars met the farmers’ needs and were advanced for on-farm testing and evaluation for livestock benefits

SAR Levels for Irradiation by a Crumpled 900 MHz Flexible Diamond Dipole

In this work, the antenna performance and Specific Absorption Rate (SAR) levels in a homogeneous phantom exposed to 900 MHz flexible diamond dipole antenna are investigated under different crumpling deformation conditions. The numerical simulations of the realistic complex two dimensional crumpling are performed by using Finite Integration Technique (FIT) which is applied in Computer Simulation Technology (CST) Microwave Studio. The validation of results with the industry standard DASY4 robot SAR measurement system is made possible with the use of homogenous phantom model. The 1 g, 10 g and point SAR are enhanced by 28.33 %, 36.75 % and 9.55 % respectively due to the antenna crumpling deformation. The short length ripple investigated in this paper shows the highest relative SAR increment

Re-theorizing the “Structure–Agency” Relationship: Figurational Theory, Organizational Change and the Gaelic Athletic Association

This article illustrates how the figurational sociology associated with Norbert Elias provides an alternative theoretical framework for explaining the relationship between, ‘individualorganization- society’ and organizational change, and in so doing transverses what is conceived as a false dichotomy between structure and agency. Through an historical case study of the Gaelic Athletic Association in Ireland, the ‘individual-organization-society’ relationship is conceptualized as overlapping figurations and organizational change is explained as figurational dynamics—the shifting social interdependencies between the individuals and groups comprising an organization, between that organization and other organizations, between social groups on a higher level of integration and competition. In tandem with this, the article illustrates how changes in the sources of power and identity are connected with these figurational dynamics