1,561 research outputs found

    The wave numbers of supercritical surface tension driven Benard convection

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    The cell size or the wave numbers of supercritical hexagonal convection cells in primarily surface tension driven convection on a uniformly heated plate was studied experimentally in thermal equilibrium in thin layers of silicone oil of large aspect ratio. It was found that the cell size decreases with increased temperature difference in the slightly supercritical range, and that the cell size is unique within the experimental error. It was also observed that the cell size reaches a minimum and begins to increase at larger temperature differences. This reversal of the rate of change of the wave number with temperature difference is attributed to influences of buoyancy on the fluid motion. The consequences of buoyancy were tested with three fluid layers of different depth

    Primordial helium recombination III: Thomson scattering, isotope shifts, and cumulative results

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    Upcoming precision measurements of the temperature anisotropy of the cosmic microwave background (CMB) at high multipoles will need to be complemented by a more complete understanding of recombination, which determines the damping of anisotropies on these scales. This is the third in a series of papers describing an accurate theory of HeI and HeII recombination. Here we describe the effect of Thomson scattering, the 3^3He isotope shift, the contribution of rare decays, collisional processes, and peculiar motion. These effects are found to be negligible: Thomson and 3^3He scattering modify the free electron fraction xex_e at the level of several ×10−4\times 10^{-4}. The uncertainty in the 23Po−11S2^3P^o-1^1S rate is significant, and for conservative estimates gives uncertainties in xex_e of order 10−310^{-3}. We describe several convergence tests for the atomic level code and its inputs, derive an overall CℓC_\ell error budget, and relate shifts in xe(z)x_e(z) to the changes in CℓC_\ell, which are at the level of 0.5% at ℓ=3000\ell =3000. Finally, we summarize the main corrections developed thus far. The remaining uncertainty from known effects is ∼0.3\sim 0.3% in xex_e.Comment: 19 pages, 15 figures, to be submitted to PR

    Nearest neighbor - A new non-parametric test used for classifying spectral data

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    Nonparametric statistical interference program for spectral data classificatio

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    Business in Nebraska # 270 - March 1967

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    Nebraska\u27s Agricultural Exports (Dorothy Switzer) Importance of Nebraska as the 9th ranking state in the nation and 4th in the top-ranking region, the West North Central, in value of agricultural commodity shipments in fiscal 1965-66 has been revealed in a new study by the Economic Research Service of the I.S. Department of Agriculture. Because Nebraska is one of the ten leading states in farm exports in this country, which is in turn the world\u27s largest exporter of such commodities, explicit world market information pertaining to the state has long been sought. The significance of such information is considerable both to Nebraska farmers and to that part of the business community dependent, to whatever extent, upon the agricultural sector of the economy. Business Summary (E. L. Burgess) December\u27s dollar volume of business in Nebraska increased 2.2% over last year compared with a 4.0% increase for the U.S. Nebraska\u27s physical volume changes from last month +4.9% and +1.1% respectively. construction activity in Nebraska remained down from the previous year (-16.1%). The only other indicator showing a decline from a year ago for Nebraska was electricity produced (-1.6%)

    Business in Nebraska #283 - April 1968

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    Nebraska Educational Expenditures (Dorothy Switzer) In terms of expenditure, education is by far the leading function of state and local government. In terms of socio-economic progress in the modern world, attainment of high educational standards is obligatory. Educational expenditures in Nebraska in comparison to other states, therefore, become a matter of extreme urgency as we attempt to build a climate conducive to economic and business growth. Business Summary (E. L. Burgess) January\u27s dollar volume of business in Nebraska (Table I) rose 10.5% from January, 1967. Nebraska\u27s physical volume for the same period rose 6.3%. This indicates a significant rise in prices during this period. The U.S. dollar volume increased 8.8% and the physical volume increased 5.2%. Nebraska\u27s December, 1967, to January, 1968, changes in dollar volume and physical volume were +4.7% and +0.9%. January, 1967, to January, 1968, changes in the individual business indicators ranged from +1.0% for construction activity to +11.2% for life insurance sales and electricity produced. How Does Your City Grow? (E. D. Solberg

    Business in Nebraska #286 - July 1968

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    Implications of the Growth of Corporate Farming (Dorothy Switzer) Economic studies of farm size have shown that, as farm size increases, average costs either decrease, remain about the same, or increase slightly for very large farms- but still remain below average returns. If this were always so, large farms would be the most profitable, and it might be expected that the size distribution of farms would rapidly shift in this direction. But, as Wilcox reported to the Subcommittee on Antitrust and Monopoly, farm size has been increasing almost uniformly for all size categories. Of all farms, the largest 10 percent produced 44 percent of all farm production in 1949, 46 percent in 1959, and 48 percent in 1964. The smallest 20 percent of all farms produced about 3 percent in each of these years. Business Summary (E. L. Burgess) In April, retail sales (-3.0%) and construction activity (-27.5%) were the only Nebraska business indicators below April, 1967, levels. The indexes below. with April, 1960, equal to 100.0, indicate the extent of the decline in construction activity. Factory Farms or Family Farms (Everett E. Peterson and Glen Vollmar) Symposium on the Great Plains (Dorothy Switzer) Review

    Prolonged-acting, multi-targeting gallium nanoparticles potently inhibit growth of both HIV and mycobacteria in co-infected human macrophages.

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    Human immunodeficiency virus (HIV) infection and Mycobacterium tuberculosis (TB) are responsible for two of the major global human infectious diseases that result in significant morbidity, mortality and socioeconomic impact. Furthermore, severity and disease prevention of both infections is enhanced by co-infection. Parallel limitations also exist in access to effective drug therapy and the emergence of resistance. Furthermore, drug-drug interactions have proven problematic during treatment of co-incident HIV and TB infections. Thus, improvements in drug access and simplified treatment regimens are needed immediately. One of the key host cells infected by both HIV and TB is the mononuclear phagocyte (MP; monocyte, macrophage and dendritic cell). Therefore, we hypothesized that one way this can be achieved is through drug-targeting by a nanoformulated drug that ideally would be active against both HIV and TB. Accordingly, we validated macrophage targeted long acting (sustained drug release) gallium (Ga) nanoformulation against HIV-mycobacterium co-infection. The multi-targeted Ga nanoparticle agent inhibited growth of both HIV and TB in the macrophage. The Ga nanoparticles reduced the growth of mycobacterium and HIV for up to 15 days following single drug loading. These results provide a potential new approach to treat HIV-TB co-infection that could eventually lead to improved clinical outcomes

    Hydrogen Recombination with Multilevel atoms

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    Hydrogen recombination is one of the most important atomic processes in many astrophysical objects such as Type II supernova (SN~II) atmospheres, the high redshift universe during the cosmological recombination era, and H II regions in the interstellar medium. Accurate predictions of the ionization fraction can be quite different from those given by a simple solution if one takes into account many angular momentum sub-states, non-resonant processes, and calculates the rates of all atomic processes from the solution of the radiative transfer equation instead of using a Planck function under the assumption of thermal equilibrium. We use the general purpose model atmosphere code PHOENIX 1D to compare how the fundamental probabilities such as the photo-ionization probability, the escape probability, and the collisional de-excitation probability are affected by the presence of other metals in the environment, multiple angular momentum sub-states, and non-resonant processes. Our comparisons are based on a model of SN 1999em, a SNe Type II, 20 days after its explosion.Comment: 29 pages, 12 figures, MNRAS, in pres
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