684 research outputs found
The missing Rheic Ocean magmatic arcs: Provenance analysis of Late Paleozoic
Early Carboniferous turbiditic sedimentary rocks in synorogenic basins located on both sides of the Rheic suture in
SW Iberiawere studied for provenance analysis. An enigmatic feature of this suture, which resulted from closure
of the Rheic Ocean with the amalgamation of Pangea in the Late Carboniferous, is that there are no recognizable
mid- to Late Devonian subduction-related magmatic rocks,which should have been generated during the process
of subduction, on either side of it. UâPb LAâICP-MS geochronology of detrital zircons from Early Carboniferous
turbidites in the vicinity of the Rheic suture in SW Iberia, where it separates the OssaâMorena Zone (with
Gondwana continental basement) to the north from the South Portuguese Zone (with unknown/Meguma?
continental basement) to the south, reveals the abundance of mid- to Late Devonian (51â81%) and Early
Carboniferous (13â25%) ages. The Cabrela andMĂ©rtola turbidites of the OssaâMorena and South Portuguese
zones, respectively, are largely devoid of older zircons, differing from the age spectra of detrital zircons in
the oldest (Late Devonian) strata in the underlying South Portuguese Zone, which contain abundant Cambrian
and Neoproterozoic ages. Mid- to Late Devonian zircons in the Cabrela Formation (age cluster at c. 391 Ma,
EifelianâGivetian transition) and MĂ©rtola Formation (age clusters at c. 369 Ma and at c. 387 Ma, Famennian
and Givetian respectively) are attributable to a source terrane made up of magmatic rocks with a simple
geological history lacking both multiple tectonic events and older continental basement. The terrane capa-
ble of sourcing sediments dispersed on both sides of the suture is interpreted to have been completely re-
moved by erosion in SW Iberia. Given that closure of the Rheic Ocean required subduction of its oceanic
lithosphere and the absence of significant arc magmatism on either side of the Rheic suture, we suggest:
1) the source of the zircons in the SW Iberia basins was a short-lived Rheic ocean magmatic arc, and
2) given the lack of older zircons in the SW Iberia basins, this short-lived arc was probably developed
in an intra-oceanic environment
Influence of season on plasmatic cortisol and IGF -I in dairy cows under thermal comfort.
Objectives: Access to evaporative cooling system can increase production in dairy cows due to improve thermal comfort. The aim of this study was to evaluate the impact of ambient temperature on thermoregulation, cortisol and IGF-I, and determine the efficiency of evaporative cooling system on the
physiological responses in different weather patterns.
Materials and Methods: 24 Holstein cows were housed in two groups with or without access to cooling system with fans and mist in the free-stall. The parameters analyzed were: rectal temperature (TR ), body surface (TS ), internal base of tail (TC ), respiratory rate (FR), cortisol and IGF-I during the
morning milking (700h) and afternoon (1430h) in five different weather patterns throughout the year (fall, winter, spring, dry summer and rainy summer).
Results: TR , TS , TC and FR were lower in the morning (P<0.01). Cooling system did not affect rectal temperature, with both groups had values below 38.56 over the year (P=0.11). We observed an upward trend (P<0.05) in
plasma cortisol concentrations between autumn and winter, starting the decline until the dry summer and a further increase during the rainy summer. A gradual increase of IGF-I happened between autumn until the dry summer,
and decreased during the rainy summer (P<0.05). Cortisol and IGF-I may have been influenced by light hours. TR showed a moderate and positive correlation (P <0.001) with the TS (0.46) and FR (0.35). The air temperature and THI showed positive moderate to high correlations with TR , TC , TS and FR (P <0.001).
Conclusions: The ambient temperature influences positively on the physiological variables, independent of the cooling system, but cooled animals kept milk production even during the summer. The plasma concentrations of cortisol and IGF-I may have been influenced by the seasons and the milk production
Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration
Extensive experimental data from high-energy nucleus-nucleus collisions were
recorded using the PHENIX detector at the Relativistic Heavy Ion Collider
(RHIC). The comprehensive set of measurements from the first three years of
RHIC operation includes charged particle multiplicities, transverse energy,
yield ratios and spectra of identified hadrons in a wide range of transverse
momenta (p_T), elliptic flow, two-particle correlations, non-statistical
fluctuations, and suppression of particle production at high p_T. The results
are examined with an emphasis on implications for the formation of a new state
of dense matter. We find that the state of matter created at RHIC cannot be
described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted
to Nuclear Physics A as a regular article; v3 has minor changes in response
to referee comments. Plain text data tables for the points plotted in figures
for this and previous PHENIX publications are (or will be) publicly available
at http://www.phenix.bnl.gov/papers.htm
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) and the direct CP asymmetry in B0 -> K*0 gamma
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1
of pp collision data collected by the LHCb experiment at a centre-of-mass
energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 ->
phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the
first uncertainty is statistical, the second is the experimental systematic
uncertainty and the third is associated with the ratio of fragmentation
fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the
branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x
10^{-5}.
The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with
the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/-
0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the
previous experimental results and theoretical expectations.Comment: 21 pages, 3 figues, 4 table
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