820 research outputs found
Aerolastic tailoring and integrated wing design
Much has been learned from the TSO optimization code over the years in determining aeroelastic tailoring's place in the integrated design process. Indeed, it has become apparent that aeroelastic tailoring is and should be deeply embedded in design. Aeroelastic tailoring can have tremendous effects on the design loads, and design loads affect every aspect of the design process. While optimization enables the evaluation of design sensitivities, valid computational simulations are required to make these sensitivities valid. Aircraft maneuvers simulated must adequately cover the plane's intended flight envelope, realistic design criteria must be included, and models among the various disciplines must be calibrated among themselves and with any hard-core (e.g., wind tunnel) data available. The information gained and benefits derived from aeroelastic tailoring provide a focal point for the various disciplines to become involved and communicate with one another to reach the best design possible
The Impact of Hosting a Major Sport Event on the South African Economy
The impact of the sporting industry on economic decision making has increased dramatically since the global media explosion in the 1980s. Tourism and advertising revenues generated by these mega-events have become a major boost to the economies of hosting nations. In addition, globalisation has placed great emphasis on the importance of foreign direct investment (FDI), especially to developing countries. This paper seeks to examine the impact of the pre-event phase expenditure attributed to the hosting of the 2010 FIFA World Cup on the South African economy. In this phase, expenditure is mainly geared towards the construction and improvement of infrastructure required to successfully host the event. Using a Computable General Equilibrium (CGE) model developed specifically for the South African economy, the impact of the pre-event phase on the local economy is measured. It is found that there is a positive impact on most macroeconomic variables, including GDP and employment. With the potential economic benefits of the event and post-event phases of the World Cup also taken into account, it can be concluded with relative certainty that the impact of hosting a mega-event on the South African economy is beneficial towards achieving higher economic growth and development. In addition to analysing the impact of the 2010 FIFA World Cup, the outcomes are also used to briefly examine the feasibility of South Africa’s bid to host the 2011 IRB World Cup and the 2016 Olympic Games.computable general equilibrium, mega-events, economic development
NASA tungsten reactor radiation chemistry studies Final report
Cadmium sulfate poison control solutions for tungsten water moderated reacto
Ship-borne aerosol profiling with lidar over the Atlantic Ocean: from pure marine conditions to complex dust–smoke mixtures
The multi-wavelength Raman lidar PollyXT has been
regularly operated aboard the research vessel Polarstern on
expeditions across the Atlantic Ocean from north to south and vice versa. The
lidar measurements of the RV Polarstern cruises PS95 from
Bremerhaven, Germany, to Cape Town, Republic of South Africa (November 2015),
and PS98 from Punta Arenas, Chile, to Bremerhaven, Germany (April/May 2016),
are presented and analysed in detail. The latest set-up of
PollyXT allows improved coverage of the marine boundary
layer (MBL) due to an additional near-range receiver.Three case studies provide an overview of the aerosol detected over the
Atlantic Ocean. In the first case, marine conditions were observed near South
Africa on the autumn cruise PS95. Values of optical properties
(depolarisation ratios close to zero, lidar ratios of 23 sr at 355 and
532 nm) within the MBL indicate pure marine aerosol. A layer of dried marine
aerosol, indicated by an increase of the particle depolarisation ratio to
about 10 % at 355 nm (9 % at 532 nm) and thus confirming the
non-sphericity of these particles, could be detected on top of the MBL. On
the same cruise, an almost pure Saharan dust plume was observed near the
Canary Islands, presented in the second case. The third case deals with
several layers of Saharan dust partly mixed with biomass-burning smoke
measured on PS98 near the Cabo Verde islands. While the MBL was partly mixed
with dust in the pure Saharan dust case, an almost marine MBL was observed in
the third case.A statistical analysis showed latitudinal differences in the optical
properties within the MBL, caused by the down-mixing of dust in the tropics
and anthropogenic influences in the northern latitudes, whereas the optical
properties of the MBL in the Southern Hemisphere correlate with typical
marine values. The particle depolarisation ratio of dried marine layers
ranged between 4 and 9 % at 532 nm.Night measurements from PS95 and PS98 were used to illustrate the potential
of aerosol classification using lidar ratio, particle depolarisation ratio at
355 and 532 nm, and Ångström exponent. Lidar ratio and particle
depolarisation ratio have been found to be the main indicator for particle
type, whereas the Ångström exponent is rather variable.</p
SESQUITERPENE LACTONES FROM PERITYLE EMORYI
Abstract-The extract of the aerial parts of Perityle emoryi gave, in addition to seven known sesquiterpene lactones, six new germacranolides and a guaianolide as well as a further thymol derivative together with several known ones and two labdanes. The structures were elucidated by high field 'H NMR spectroscopy. The chemotaxonomic aspects are discussed briefly
Processing of Thionin Precursors in Barley Leaves by a Vacuolar Proteinase
Thionins are synthesized as precursors with a signal peptide and a long C-terminal acidic peptide that is post-translationally processed. A fusion protein including the maltose-binding protein from Eschrrichia coli (MalE), thionin DG3 froin barley leaves, and its acidic C-terminal peptide has been used to obtain antibodies that recognize both domains of the precursor. In barley leaf sections. mature thionins accuinulated in the vacuolar content, while the acidic peptide was not detected in any cell fraction. Brefeldin A and inonensin inhibited processing of the precursor but its export from the microsomal fraction was not inhibited. Both purified vacuoles aiid an acid (pH 5.5) extract from leaves processed the fusion protein into a MalE-thionin and an acidic peptide fragment. A 70-kDa proteinase that effected this cleavage was purified froin the acid extract. Processing of the fusion protein by both lysed vacuoles and the purified proteinase was inhibited by Zn2+ and by Cu2+, but not by inhibitors of the previously described vacuolar processing thiol or aspartic proteinases. In vivo processing of the thionin precursor in leaf sections was also inhibited by Zn+, and Cu2+, Variants of the fusion protein with altered processing sites that represented thme of thionin precursors from different taxa were readily processed by the proteinase, whereas changing the polarity of either the C-terminal or N-terminal residues of the processing site prevented cleavage by the proteinase
Continuous vertical aerosol profiling with a multi-wavelength Raman polarization lidar over the Pearl River Delta, China
A dataset of particle optical properties of the highly polluted
atmosphere over the Pearl River Delta (PRD), Guangzhou, China, is presented
in this paper. The data were derived from the measurements of a
multi-wavelength Raman and depolarization lidar PollyXT and a
co-located AERONET sun photometer. The measurement campaign was conducted
from November 2011 to mid-June 2012. These are the first Raman lidar
measurements in the PRD that lasted for several months.
A mean value of aerosol optical depth (AOD) of 0.54 ± 0.33 was observed
by the sun photometer at 500 nm in the polluted atmosphere over this
megacity for the whole measurement period. The lidar profiles frequently show
lofted aerosol layers, which reach altitudes of up to 2 to 3 km
and, especially during the spring
season, up to 5 km. These layers contain between 12 and 56 % of the
total AOD, with the highest values in spring. The aerosol types in these
lofted layers are classified by their optical properties. The observed lidar
ratio values range from 30 to 80 sr with a mean value of
48.0 ± 10.7 sr at 532 nm. The linear particle depolarization ratio at
532 nm lies mostly below 5 %, with a mean value of
3.6 ± 3.7 %. The majority of the Ångström exponents lie
between 0.5 and 1.5, indicating a mixture of fine- and coarse-mode aerosols.
These results reveal that mostly urban pollution particles mixed with
particles produced from biomass and industrial burning are present in the
atmosphere above the Pearl River Delta. Trajectory analyses show that these
pollution mixtures arise mainly from local and regional sources
Increased glutamine in leaves of poplar transgenic with pine GS1a caused greater anthranilate synthetase α-subunit (ASA1) transcript and protein abundances: an auxin-related mechanism for enhanced growth in GS transgenics?
The initial reaction in the pathway leading to the production of indole-3-acetic acid (IAA) in plants is the reaction between chorismate and glutamine to produce anthranilate, catalysed by the enzyme anthranilate synthase (ASA; EC 4.1.3.27). Compared with non-transgenic controls, leaves of transgenic poplar with ectopic expression of the pine cytosolic glutamine synthetase (GS1a; EC 6.3.1.2) produced significantly greater glutamine and significantly enhanced ASA α-subunit (ASA1) transcript and protein (approximately 130% and 120% higher than in the untransformed controls, respectively). Similarly, tobacco leaves fed with 30 mM glutamine and 2 mM chorismate showed enhanced ASA1 transcript and protein (175% and 90% higher than controls, respectively). Furthermore, free IAA was significantly elevated both in leaves of GS1a transgenic poplar and in tobacco leaves fed with 30 mM glutamine and 2 mM chorismate. These results indicated that enhanced cellular glutamine may account for the enhanced growth in GS transgenic poplars through the regulation of auxin biosynthesis
Thiarubrine A, a bioactive constituent of Aspilia (Asteraceae) consumed by wild chimpanzees
Two African species of Aspilia (Asteraceae), which are used medicinally by man and which are eaten by wild chimpanzees in an unusual manner, were found to contain the potent antibiotic thiarubrine A as a major leaf phytochemical. Its presence in leaf material strengthens the view that the feeding behavior of wild chimpanzees is related to special physiological or pharmacological effects on the animals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42789/1/18_2005_Article_BF02004537.pd
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