Research Collaborations and Scientific productivity among the Research Universities in South Africa

This study presents the share of 5 most productive South African institutions for the main stream scientific out put covering the 10 year periods of 1995-2004. This paper discusses the distribution of publications by institutions, Index of specialization, collaboration and pattern of co-authorship. The result shows that South African authors collaborate more frequently with international authors with a percentage of (73.99%) than did so for national collaboration which amount to (26.01%). This was confirmed statistically at the confidence level of P-value 0.025. A further non-parametric chi-square statistical analysis illustrated that there are significant differences in the proportion of co-authorship among the 5 institutions (p-value0.005)

Measurements of jet quenching with semi-inclusive charged jet distributions in Au+AuAu+Au collisions at sNN\sqrt{s_{NN}}=200 GeV

We report measurements of jet quenching in $Au+Au$ collisions at $\sqrt{s_{NN}}$=200 GeV, based on the semi-inclusive distribution of reconstructed charged particle jets recoiling from a high $p_T$ hadron trigger. Jets are reconstructed with the anti-k$_T$ algorithm ($R$=0.2 to 0.5), with low IR-cutoff of track constituents ($p_{T}>0.2$ GeV/c). Uncorrelated background is corrected using a novel mixed-event technique, with no fragmentation bias imposed by the correction procedure on the accepted recoil jet population. Corrected recoil jet distributions, reported in the range $0<p_{T,jet}^{ch}<30$ GeV/c, are used to measure jet yield suppression, jet energy loss, and intra-jet broadening. The first search for QCD Moli\`ere scattering of jets in hot QCD matter at RHIC is reported.Comment: Proceedings of the Quark Matter 2015 conferenc

Reply to the comment by Jacobs and Thorpe

Reply to a comment on "Infinite-Cluster geometry in central-force networks", PRL 78 (1997), 1480. A discussion about the order of the rigidity percolation transition.Comment: 1 page revTe

Assessment of clear and cloudy sky parameterizations for daily downwelling longwave radiation over different land surfaces in Florida, USA

Clear sky downwelling longwave radiation (Rldc) and cloudy sky downwelling longwave radiation (Rld) formulas were tested across eleven sites in Florida. The Brunt equation, using air vapor pressure and temperature measurements, provides the best Rldc estimates with a root mean square error of less than around 12 Wm−2 across all sites. The Crawford and Duchon\u27s cloudiness factor with Brunt equation is recommended for Rld calculations. This combined approach requires no local calibration and estimates Rld with a root mean square error of less than around 13 Wm−2 and squared correlation coefficients that typically exceed 0.9

Diagnosis of Local Land-Atmosphere Feedbacks in India

Following the convective triggering potential (CTP)–humidity index (HIlow) framework by Findell and Eltahir, the sensitivity of atmospheric convection to soil moisture conditions is studied for India. Using the same slab model as Findell and Eltahir, atmospheric conditions in which the land surface state affects convective precipitation are determined. For India, CTP–HIlow thresholds for land surface–atmosphere feedbacks are shown to be slightly different than for the United States. Using atmospheric sounding data from 1975 to 2009, the seasonal and spatial variations in feedback strength have been assessed. The patterns of feedback strengths thus obtained have been analyzed in relation to the monsoon timing. During the monsoon season, atmospheric conditions where soil moisture positively influences precipitation are present about 25% of the time. During onset and retreat of the monsoon, the south and east of India show more potential for feedbacks than the north. These feedbacks suggest that large-scale irrigation in the south and east may increase local precipitation. To test this, precipitation data (from 1960 to 2004) for the period about three weeks just before the monsoon onset date have been studied. A positive trend in the precipitation just before the monsoon onset is found for irrigated stations. It is shown that for irrigated stations, the trend in the precipitation just before the monsoon onset is positive for the period 1960–2004. For nonirrigated stations, there is no such upward trend in this period. The precipitation trend for irrigated areas might be due to a positive trend in the extent of irrigated areas, with land–atmosphere feedbacks inducing increased precipitation

The EET Horizontal Tails Investigation and the EET Lateral Controls Investigation

In the energy efficient transport (EET) Horizontal Tails Investigation, aerodynamic data were measured for five different horizontal tails on a full span model with a wide body fuselage. Three of the horizontal tails were low tail configurations and two were T tail configurations. All tails were tested in conjunction with two wings, a current wide body wing and a high aspect ratio supercritical wing. Local downwash angles and dynamic pressures in the vicinity of the tails were measured using a yaw head rake. The results provide a comparison of the aerodynamic characteristics of the two wing configurations at trimmed conditions for Mach numbers between 0.60 and 0.90. In the EET Lateral Controls Investigation, the control effectiveness of a conventional set of lateral controls was measured over a Mach number range from 0.60 to 0.90 on a high aspect ratio supercritical wing semispan model. The conventional controls included a high speed aileron, a low speed aileron, and six spoiler segments. The wing was designed so that the last 25% of the chord is removable to facilitate testing of various control systems. The current status and an indication of the data obtained in these investigations are presented