Inclusive transverse momentum spectra of primary charged particles in Pb–Pb collisions at sNN=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 |η|<0.8 and 0.3<pT<20 GeV/c are compared to the expectation in pp collisions at the same sNN, scaled by the number of underlying nucleon–nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAA. The result indicates only weak medium effects (RAA≈0.7) in peripheral collisions. In central collisions, RAA reaches a minimum of about 0.14 at pT=6–7 GeV/c and increases significantly at larger pT. The measured suppression of high-pT 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.
To evaluate and compare the mechanical resistance to tearing of the anterior lens capsule opening after staining with different concentrations of trypan blue in ex vivo porcine eyes.
Semmelweis ...University, and Budapest University of Technology and Economics, Budapest, Hungary.
Experimental study.
The study comprised 75 porcine eyes. The capsule was unstained in the Control Group (n = 25 eyes), 0.06% trypan blue was used to stain the capsule in Stained 1 Group (n = 25 eyes), and 0.1% trypan blue was used to stain the capsule in Stained 2 Group (n = 25 eyes). After capsulorhexis, the capsule openings were stretched with custom-designed testing equipment until they ruptured. The rupture force (RF), circumference stretching ratio (CSR), and secant modulus at 10 mN (SM10mN) and 50 mN (SM50mN) were evaluated.
In total, 75 eyes were enrolled. There were no statistically significant differences in the RF (P = .8924) or CSR (P = .3876) among the groups. There were no statistically significant differences in the SM10mN (P = .8215) or SM50mN (P = .4184) among the groups.
In this porcine eye model, the trypan blue concentrations that are routinely used in cataract surgery had no effect on capsular rim stability.
A
bstract
The elliptic flow coefficient (
v
2
) of identified particles in Pb-Pb collisions at
s
N
N
=
2.76
TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results ...were obtained with the Scalar Product method, a two-particle correlation technique, using a pseudo-rapidity gap of |Δ
η
|
>
0
.
9 between the identified hadron under study and the reference particles. The
v
2
is reported for
π
±
, K
±
, K
S
0
,
p
+
p
¯
,
ϕ
,
Λ
+
Λ
¯
,
Ξ
−
+
Ξ
¯
+
and
Ω
−
+
Ω
¯
+
in several collision centralities. In the low transverse momentum (
p
T
) region,
p
T
<
3 GeV/
c
,
v
2
(
p
T
) exhibits a particle mass dependence consistent with elliptic flow accompanied by the transverse radial expansion of the system with a common velocity field. The experimental data for
π
±
and the combined K
±
and K
S
0
results, are described fairly well by hydrodynamic calculations coupled to a hadronic cascade model (VISHNU) for central collisions. However, the same calculations fail to reproduce the
v
2
(
p
T
) for
p
+
p
¯
,
ϕ
,
Λ
+
Λ
¯
and
Ξ
−
+
Ξ
¯
+
. For transverse momentum values larger than about 3 GeV/
c
, particles tend to group according to their type, i.e. mesons and baryons. The present measurements exhibit deviations from the number of constituent quark (NCQ) scaling at the level of ±20% for
p
T
>
3 GeV/
c
.
The pT-differential production cross sections of the prompt charmed mesons D0, D+, D*+, and D+s and their charge conjugate in the rapidity interval –0.96 < ycms < 0.04 were measured in p–Pb ...collisions at a center-of-mass energy √sNN = 5.02 TeV with the ALICE detector at the LHC. The nuclear modification factor RpPb, quantifying the D-meson yield in p–Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15%–20% uncertainties with unity in the transverse momentum interval 1 < pT < 24 GeV/c. No significant difference among the RpPb of the four D-meson species is observed. The results are described within uncertainties by theoretical calculations that include initial-state effects. In conclusion, the measurement adds experimental evidence that the modification of the momentum spectrum of D mesons observed in Pb-Pb collisions with respect to pp collisions is due to strong final-state effects induced by hot partonic matter.
To evaluate and compare the mechanical properties of anterior capsule opening performed with femtosecond laser capsulotomy at different energy settings in ex vivo porcine anterior lens capsule ...specimens.
Twenty-five fresh porcine eyes per group were included in the study. Femtosecond laser capsulotomy was performed with three different pulse energy levels: 2 µJ (low energy group), 5 µJ (intermediate energy group), and 10 µJ (high energy group). The capsule openings were stretched with universal testing equipment until they ruptured. The morphologic profile of the cut capsule edges was evaluated using scanning electron microscopy.
The high energy group had significantly lower rupture force (108 ± 14 mN) compared to the intermediate energy group (118 ± 10 mN) (P < .05) and low energy group (119 ± 11 mN) (P < .05), but the difference between the intermediate energy and low energy groups was not significant (P = .9479). The high energy group had significantly lower circumference stretching ratio (144% ± 3%) compared to the intermediate energy group (148% ± 3%) (P < .05) and low energy group (148% ± 3%) (P < .05), but the difference between the intermediate energy group and low energy group was not significant (P = .9985). Scanning electron microscopy images showed that the edge was only serrated with low and intermediate energy, but additional signs of collagen melting and denaturation were observed at high energy.
Anterior capsule openings created at a high energy level were slightly weaker and less extensible than those created at low or intermediate levels, possibly due to the increased thermal effect of photo-disruption.
We report the transverse energy (ET) measured with ALICE at midrapidity in Pb-Pb collisions at sNN=2.76 TeV as a function of centrality. The transverse energy was measured using identified ...single-particle tracks. The measurement was cross checked using the electromagnetic calorimeters and the transverse momentum distributions of identified particles previously reported by ALICE. The results are compared to theoretical models as well as to results from other experiments. The mean ET per unit pseudorapidity (η), (dET/dη), in 0%-5% central collisions is 1737±6(stat.)±97(sys.) GeV. We find a similar centrality dependence of the shape of (dET/dη) as a function of the number of participating nucleons to that seen at lower energies. The growth in (dET/dη) at the LHC energies exceeds extrapolations of low-energy data. We observe a nearly linear scaling of (dET/dη) with the number of quark participants. With the canonical assumption of a 1 fm/c formation time, we estimate that the energy density in 0%-5% central Pb-Pb collisions at sNN=2.76 TeV is 12.3±1.0GeV/fm3 and that the energy density at the most central 80fm2 of the collision is at least 21.5±1.7GeV/fm3. This is roughly 2.3 times that observed in 0%-5% central Au-Au collisions at sNN=200 GeV.
Management practices can disturb ecological communities in grazing lands, which represent one-quarter of land surface. But three knowledge gaps exist regarding disturbances: disturbances potentially ...interact but are most often studied singly; experiments with multiple ecosystems as treatment units are rare; and relatively new metrics of phylogenetic community structure have not been widely applied. We addressed all three of these needs with a factorial experiment; 40 seasonal wetlands embedded in a Florida ranch were treated with pasture intensification, cattle exclosure, and prescribed fire. Treatment responses were evaluated through four years for aquatic beetle (Coleoptera: Adephaga) assemblages using classic ecological metrics (species richness, diversity) and phylogenetic community structure (PCS) metrics. Adephagan assemblages consisted of 23 genera representing three families in a well-resolved phylogeny. Prescribed fire significantly reduced diversity one year post-fire, followed by a delayed pasture × fire interaction. Cattle exclosure significantly reduced one PCS metric after one year and a delayed pasture × fence × fire interaction was detected with another PCS metric. Overall, effects of long-term pasture intensification were modified by cattle exclosure and prescribed fire. Also, PCS metrics revealed effects otherwise undetected by classic ecological metrics. Management strategies (e.g., "flash grazing," prescribed fires) in seasonal wetlands may successfully balance economic gains from high forage quality with ecological benefits of high wetland diversity in otherwise simplified grazing lands. Effects are likely taxon specific; multiple taxa should be similarly evaluated.
The Red carrying the news around the world: Most newspapers and journals worldwide (including Angewandte Chemie) are printed with Pigment Red 57:1. The crystal structures of this pigment in various ...hydration states have now been determined by X‐ray powder diffraction.
PDF
