6,004 research outputs found
Inelaticity in hadron-nucleus collisions from emulsion chamber studies
The inelasticity of hadron-carbon nucleus collisions in the energy region
exceeding 100 TeV is estimated from the carbon-emulsion chamber data at Pamirs
to be . When combined with the recently presented data on
hadron-lead nucleus collisions taken at the same energy range it results in the
mass number dependence of inelasticity. The evaluated partial
inelasticity for secondary () interactions, ,
suggests that the second and higher interactions of the excited hadron inside
the nucleus proceed with only slight energy losses.Comment: LaTeX file and 5 LaTeX files with figures, 11 pages altogether.
Thoroughly rewritten and modified, one figure addded one removed. To be
published in Phys. Rev.
The Offline Software Framework of the Pierre Auger Observatory
The Pierre Auger Observatory is designed to unveil the nature and the origins
of the highest energy cosmic rays. The large and geographically dispersed
collaboration of physicists and the wide-ranging collection of simulation and
reconstruction tasks pose some special challenges for the offline analysis
software. We have designed and implemented a general purpose framework which
allows collaborators to contribute algorithms and sequencing instructions to
build up the variety of applications they require. The framework includes
machinery to manage these user codes, to organize the abundance of
user-contributed configuration files, to facilitate multi-format file handling,
and to provide access to event and time-dependent detector information which
can reside in various data sources. A number of utilities are also provided,
including a novel geometry package which allows manipulation of abstract
geometrical objects independent of coordinate system choice. The framework is
implemented in C++, and takes advantage of object oriented design and common
open source tools, while keeping the user side simple enough for C++ novices to
learn in a reasonable time. The distribution system incorporates unit and
acceptance testing in order to support rapid development of both the core
framework and contributed user code.Comment: 4 pages, 2 figures, presented at IEEE NSS/MIC, 23-29 October 2005,
Puerto Ric
Mechanical performance of geopolymeric mortars based on tunisian calcined clay, fly ash and metakaolin
Infrastructure rehabilitation represents a multitrillion dollar opportunity for the construction industry.
Since the majority of the existent infrastructures are Portland cement concrete based this means that concrete infrastructure rehabilitation is a hot issue to be dealt with. Geopolymers are novel inorganic binders with high potential to replace Portland cement based ones. So far very few studies in the geopolymer field have addressed the rehabilitation of deteriorated concrete structures. This paper discloses results of an investigation concerning the development geopolymeric repair mortars. The mortars are based on Tunisian clay coming from Medenine region, plus calcium hydroxide, sodium silicate and sodium hydroxide. Results show that the geopolymeric mortar has a high compressive strength and a lower unrestrained shrinkage performance as long as partial replacement by metakaolin is carried out. The results also show that Tunisian calcined clay based mortars have hydration products with typical geopolymeric phases
Antioxidant, Anti-5-lipoxygenase and Antiacetylcholinesterase Activities of Essential Oils and Decoction Waters of Some Aromatic Plants
The scavenging of free radicals and superoxide anion, the inhibition of 5-lipoxygenase and the antiacetylcholinesterase activities of essential oils and decoction waters of eight aromatic plants (Dittrichia viscosa, Foeniculum vulgare, Origanum vulgare, Salvia officinalis, Thymbra capitata, Thymus camphoratus, Thymus carnosus and Thymus mastichina) were studied. The essential oils were dominated by 1,8-cineole in S. officinalis (59%), T. mastichina (49%) and T. camphoratus (21%); borneol (20%) in T. carnosus; carvacrol in Thymbra capitata (68%); gamma-terpinene (49%) in O. vulgare; alpha-pinene (26%) in F. vulgare; and trans-nerolidol (8%) + beta-oplopenone (7%) in D. viscosa. O. vulgare decoction waters had the highest amount of phenols (45 +/- 3mg GAE/mL) while F. vulgare only had 5 +/- 0mg GAE/mL. The decoction waters showed higher radical scavenging activity than the essential oils. O. vulgare decoction water showed the best antioxidant activity (IC(50) = 3 +/- 0 mu g/mL), while the most effective essential oils were those of Thymbra capitata (IC(50) = 61 +/- 2 mu g/mL) and O. vulgare (IC(50) = 156 +/- 5 mu g/mL). Thymbra capitata (IC(50) = 6 +/- 0 mu g/mL) decoction water showed the best superoxide anion scavenging activity. F. vulgare decoction water and essential oil revealed the best 5-lipoxygenase inhibition capacity (IC(50) = 27 +/- 1 mu g/mL and IC(50) = 68 +/- 2 mu/mL, respectively). T. mastichina (IC(50) = 46 +/- 4 mu g/mL), S. officinalis (IC(50) = 51 +/- 4 mu g/mL), Thymbra capitata (IC(50) = 52 +/- 1 mu g/mL) and T. camphoratus (IC(50) = 137 +/- 2 mu g/mL) essential oils showed the best antiacetylcholinesterase activity
Variability of olive oil cultivar on stability during storage
The fatty acid composition and stability of three Portuguese monovarietal olive oils, Cobrancosa, Macanilha and Verdeal, was studied, maintaining the olive oils at 60 degrees C for 75 and 102 days, respectively. Oleic acid was the main fatty acid (64-69%) in three olive oils cultivars, followed by palmitic acid (15-18%). The highest percentages of palmitic acid were observed in Macanilha olive oil (17-18%). Linolenic acid content was 3%, on average. Storing the oils at 60 degrees C over 75 days did not affect the levels of fatty acids. Cobrancosa and Macanilha olive oils were more resistant to hydroperoxide formation than Verdeal olive oil, whereas this oil and that of Macanilha were more resistant to the degradation of those peroxides. Cobrancosa olive oil possessed higher levels of phenols and higher ability for scavenging free radicals than the remaining oils. a-Tocopherol content was higher in Cobrancosa and Macanilha oils than in Verdeal, but a similar high degradation of this vitamin was observed in all oils, disappearing after 5 to 8 days of storage at 60 degrees C
Welcome to the Twilight Zone: The Mid-Infrared Properties of Poststarburst Galaxies
We investigate the optical and Wide-field Survey Explorer (WISE) colors of
"E+A" identified post-starburst galaxies, including a deep analysis on 190
post-starbursts detected in the 2{\mu}m All Sky Survey Extended Source Catalog.
The post-starburst galaxies appear in both the optical green valley and the
WISE Infrared Transition Zone (IRTZ). Furthermore, we find that post-starbursts
occupy a distinct region [3.4]-[4.6] vs. [4.6]-[12] WISE colors, enabling the
identification of this class of transitioning galaxies through the use of
broad-band photometric criteria alone. We have investigated possible causes for
the WISE colors of post-starbursts by constructing a composite spectral energy
distribution (SED), finding that mid-infrared (4-12{\mu}m) properties of
post-starbursts are consistent with either 11.3{\mu}m polycyclic aromatic
hydrocarbon emission, or Thermally Pulsating Asymptotic Giant Branch (TP-AGB)
and post-AGB stars. The composite SED of extended post- starburst galaxies with
22{\mu}m emission detected with signal to noise >3 requires a hot dust
component to produce their observed rising mid-infrared SED between 12 and
22{\mu}m. The composite SED of WISE 22{\mu}m non-detections (S/N<3), created by
stacking 22{\mu}m images, is also flat, requiring a hot dust component. The
most likely source of this mid-infrared emission of these E+A galaxies is a
buried active galactic nucleus. The inferred upper limit to the Eddington
ratios of post-starbursts are 1e-2 to 1e-4, with an average of 1e-3. This
suggests that AGNs are not radiatively dominant in these systems. This could
mean that including selections able to identify active galactic nuclei as part
of a search for transitioning and post-starburst galaxies would create a more
complete census of the transition pathways taken as a galaxy quenches its star
formation.Comment: 13 pages, 11 figures, accepted for publication in the Astrophysical
Journa
- …