Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in $|\eta|<0.8$ and $0.3 < p_T < 20$ GeV/$c$ are compared to the expectation in pp collisions at the same $\sqrt{s_{\rm NN}}$, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor $R_{\rm AA}$. The result indicates only weak medium effects ($R_{\rm AA} \approx$ 0.7) in peripheral collisions. In central collisions, $R_{\rm AA}$ reaches a minimum of about 0.14 at $p_{\rm T}=6$-7GeV/$c$ and increases significantly at larger $p_{\rm T}$. The measured suppression of high-$p_{\rm T}$ particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98

Production of pions, kaons and protons in pp collisions at s=900\sqrt{s}=900 GeV with ALICE at the LHC

The production of $\pi^+$, $\pi^-$, $K^+$, $K^-$, p, and pbar at mid-rapidity has been measured in proton-proton collisions at $\sqrt{s} = 900$ GeV with the ALICE detector. Particle identification is performed using the specific energy loss in the inner tracking silicon detector and the time projection chamber. In addition, time-of-flight information is used to identify hadrons at higher momenta. Finally, the distinctive kink topology of the weak decay of charged kaons is used for an alternative measurement of the kaon transverse momentum ($p_{\rm T}$) spectra. Since these various particle identification tools give the best separation capabilities over different momentum ranges, the results are combined to extract spectra from $p_{\rm T}$ = 100 MeV/$c$ to 2.5 GeV/$c$. The measured spectra are further compared with QCD-inspired models which yield a poor description. The total yields and the mean $p_{\rm T}$ are compared with previous measurements, and the trends as a function of collision energy are discussed.Comment: 24 pages, 18 captioned figures, 5 tables, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

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Effect of warming profile at the onset of incubation on early embryonic mortality in long stored broiler eggs

In 6 experiments, it was investigated whether the pattern of warming from storage temperature to incubation temperature affects early embryonic mortality in broiler eggs. The warming profile (WP) from 21°C to the final incubation temperature of 37.8°C was divided into 2 equal parts (above and below 29.4°C) and the duration of warming in both parts was varied (3 to 17 h). In all experiments, eggs were stored for 13 to 16 d at a storage temperature of 18±2°C. In experiment 1, embryo morphology was evaluated at several time points during a linear warming curve of 24 h from 21°C to an eggshell temperature (EST) of 37.8°C. Results from experiment 1 showed that during the 24 h of warming, embryos did not advance in morphological stage (P = 0.74).Results of experiment 2 and 3 showed that the duration of the WP below 29.4°C (3 to 17 h) had no effect on early embryonic mortality (P ≥ 0.77). Experiment 4 and 6 showed that in eggs from prime breeders, a slow WP (>12 h) above 29.4°C resulted in lower embryonic mortality during the first 2 d of incubation (on average 5.0%) compared to a fast WP of 3 to 6 h (on average 11.3%). In experiment 6, an interaction was found between WP and breeder flock age for embryonic mortality till day 7 of incubation (P = 0.002). Warming profile did not affect embryonic mortality during the first 7 d of incubation in eggs from the young breeder flock. However, in eggs from the prime breeder flock, a WP of 12 h in the first part of warming, followed by 17 h in the second part of warming (WP12-17) had 6.2% lower embryonic mortality in the first 7 d of incubation compared to WP12-3. It can be concluded that a slower WP above 29.4°C reduces early embryonic mortality in long stored eggs, especially those of prime breeder flocks. At this moment, it remains unclear which mechanisms are involved in this phenomenon.</p

Effect of warming profile at the onset of incubation on early embryonic mortality in long stored broiler eggs

In 6 experiments, it was investigated whether the pattern of warming from storage temperature to incubation temperature affects early embryonic mortality in broiler eggs. The warming profile (WP) from 21°C to the final incubation temperature of 37.8°C was divided into 2 equal parts (above and below 29.4°C) and the duration of warming in both parts was varied (3 to 17 h). In all experiments, eggs were stored for 13 to 16 d at a storage temperature of 18±2°C. In experiment 1, embryo morphology was evaluated at several time points during a linear warming curve of 24 h from 21°C to an eggshell temperature (EST) of 37.8°C. Results from experiment 1 showed that during the 24 h of warming, embryos did not advance in morphological stage (P = 0.74).Results of experiment 2 and 3 showed that the duration of the WP below 29.4°C (3 to 17 h) had no effect on early embryonic mortality (P ≥ 0.77). Experiment 4 and 6 showed that in eggs from prime breeders, a slow WP (>12 h) above 29.4°C resulted in lower embryonic mortality during the first 2 d of incubation (on average 5.0%) compared to a fast WP of 3 to 6 h (on average 11.3%). In experiment 6, an interaction was found between WP and breeder flock age for embryonic mortality till day 7 of incubation (P = 0.002). Warming profile did not affect embryonic mortality during the first 7 d of incubation in eggs from the young breeder flock. However, in eggs from the prime breeder flock, a WP of 12 h in the first part of warming, followed by 17 h in the second part of warming (WP12-17) had 6.2% lower embryonic mortality in the first 7 d of incubation compared to WP12-3. It can be concluded that a slower WP above 29.4°C reduces early embryonic mortality in long stored eggs, especially those of prime breeder flocks. At this moment, it remains unclear which mechanisms are involved in this phenomenon.</p