The correlations between different moments of two flow amplitudes, extracted with the recently developed asymmetric cumulants, are measured in Pb-Pb collisions at $\sqrt {s_{NN}}$ = 5.02 TeV recorded ...by the ALICE detector at the CERN Large Hadron Collider. The magnitudes of the measured observables show a dependence on the different moments as well as on the collision centrality, indicating the presence of nonlinear response in all even moments up to the eighth. Furthermore, the higher-order asymmetric cumulants show different signatures than the symmetric and lower-order asymmetric cumulants. Comparisons with state-of-the-art event generators using two different parametrizations obtained from Bayesian optimization show differences between data and simulations in many of the studied observables, indicating a need for further tuning of the models behind those event generators. These results provide new and independent constraints on the initial conditions and transport properties of the system created in heavy-ion collisions.
A
bstract
The production of strange hadrons (
$$ {\textrm{K}}_{\textrm{S}}^0 $$
K
S
0
, Λ, Ξ
±
, and Ω
±
), baryon-to-meson ratios (Λ
/
$$ {\textrm{K}}_{\textrm{S}}^0 $$
K
S
0
, Ξ
/
$$ ...{\textrm{K}}_{\textrm{S}}^0 $$
K
S
0
, and Ω
/
$$ {\textrm{K}}_{\textrm{S}}^0 $$
K
S
0
), and baryon-to-baryon ratios (Ξ
/
Λ, Ω
/
Λ, and Ω
/
Ξ) associated with jets and the underlying event were measured as a function of transverse momentum (
p
T
) in pp collisions at
$$ \sqrt{s} $$
s
= 13 TeV and p Pb collisions at
$$ \sqrt{s_{\textrm{NN}}} $$
s
NN
= 5
.
02 TeV with the ALICE detector at the LHC. The inclusive production of the same particle species and the corresponding ratios are also reported. The production of multi-strange hadrons, Ξ
±
and Ω
±
, and their associated particle ratios in jets and in the underlying event are measured for the first time. In both pp and p–Pb collisions, the baryon-to-meson and baryon-to-baryon yield ratios measured in jets differ from the inclusive particle production for low and intermediate hadron
p
T
(0.6–6 GeV/
c
). Ratios measured in the underlying event are in turn similar to those measured for inclusive particle production. In pp collisions, the particle production in jets is compared with P
ythia
8 predictions with three colour-reconnection implementation modes. None of them fully reproduces the data in the measured hadron
p
T
region. The maximum deviation is observed for Ξ
±
and Ω
±
which reaches a factor of about six. The event multiplicity dependence is further investigated in p−Pb collisions. In contrast to what is observed in the underlying event, there is no significant event-multiplicity dependence for particle production in jets. The presented measurements provide novel constraints on hadronisation and its Monte Carlo description. In particular, they demonstrate that the fragmentation of jets alone is insufficient to describe the strange and multi-strange particle production in hadronic collisions at LHC energies.
The ALICE Collaboration reports a differential measurement of inclusive jet suppression using pp and Pb–Pb collision data at a center-of-mass energy per nucleon–nucleon collision $\sqrt{s_{NN}}=5.02$ ...TeV. Charged-particle jets are reconstructed using the anti-$k_T$ algorithm with resolution parameters R=0.2, 0.3, 0.4, 0.5, and 0.6 in pp collisions and R=0.2, 0.4, 0.6 in central (0–10%), semi-central (30–50%), and peripheral (60–80%) Pb–Pb collisions. A novel approach based on machine learning is employed to mitigate the influence of jet background. This enables measurements of inclusive jet suppression in new regions of phase space, including down to the lowest jet $p_T$ ≥ 40 GeV/c at R=0.6 in central Pb–Pb collisions. This is an important step for discriminating different models of jet quenching in the quark–gluon plasma. The transverse momentum spectra, nuclear modification factors, derived cross section, and nuclear modification factor ratios for different jet resolution parameters of charged-particle jets are presented and compared to model predictions. A mild dependence of the nuclear modification factor ratios on collision centrality and resolution parameter is observed. The results are compared to a variety of jet-quenching models with varying levels of agreement.
International comparative studies, investigating whether disease incidence or prevalence rates differ between populations and, if so, which factors explain the observed differences, have made ...important contributions to the understanding of disease aetiology in many areas. In Phase I of the International Study of Asthma and Allergies in Childhood (ISAAC), the prevalence rates of symptoms of asthma, allergic rhinitis and atopic eczema in 13-14-yr-olds, assessed by standardised questionnaires, were found to differ >20-fold between the 155 study centres around the world. Phase II of ISAAC aims to identify determinants of these differences by studying informative populations. A detailed study protocol was developed for use in community-based random samples of children aged 9-11 yrs. The study modules include standardised questionnaires with detailed questions on the occurrence and severity of symptoms of asthma, allergic rhinitis and atopic eczema, their clinical management, and a broad range of previous and current exposure conditions. In addition, standardised protocols were applied for examination of flexural dermatitis, skin-prick testing, bronchial challenge with hypertonic saline, blood sampling for immunoglobulin E analyses and genotyping, and dust sampling for assessment of indoor exposures to allergens and endotoxin. To date, ISAAC II field work had been completed or started in 30 study centres in 22 countries. The majority of centres are in countries that participated in International Study of Asthma and Allergies in Childhood Phase I and reflect almost the full range of the observed variability in Phase I prevalence rates.
•Analysis of brGDGT distributions in global peat dataset.•Correlation of brGDGT distributions with peat pH and mean annual air temperature.•Development of peat-specific temperature and pH proxies.
...Glycerol dialkyl glycerol tetraethers (GDGTs) are membrane-spanning lipids from Bacteria and Archaea that are ubiquitous in a range of natural archives and especially abundant in peat. Previous work demonstrated that the distribution of bacterial branched GDGTs (brGDGTs) in mineral soils is correlated to environmental factors such as mean annual air temperature (MAAT) and soil pH. However, the influence of these parameters on brGDGT distributions in peat is largely unknown. Here we investigate the distribution of brGDGTs in 470 samples from 96 peatlands around the world with a broad mean annual air temperature (−8 to 27°C) and pH (3–8) range and present the first peat-specific brGDGT-based temperature and pH calibrations. Our results demonstrate that the degree of cyclisation of brGDGTs in peat is positively correlated with pH, pH=2.49×CBTpeat+8.07 (n=51, R2=0.58, RMSE=0.8) and the degree of methylation of brGDGTs is positively correlated with MAAT, MAATpeat (°C)=52.18×MBT5me′−23.05 (n=96, R2=0.76, RMSE=4.7°C). These peat-specific calibrations are distinct from the available mineral soil calibrations. In light of the error in the temperature calibration (∼4.7°C), we urge caution in any application to reconstruct late Holocene climate variability, where the climatic signals are relatively small, and the duration of excursions could be brief. Instead, these proxies are well-suited to reconstruct large amplitude, longer-term shifts in climate such as deglacial transitions. Indeed, when applied to a peat deposit spanning the late glacial period (∼15.2kyr), we demonstrate that MAATpeat yields absolute temperatures and relative temperature changes that are consistent with those from other proxies. In addition, the application of MAATpeat to fossil peat (i.e. lignites) has the potential to reconstruct terrestrial climate during the Cenozoic. We conclude that there is clear potential to use brGDGTs in peats and lignites to reconstruct past terrestrial climate.
Because of heavy dependence on fish, Amazonian riparian communities are chronically exposed to high levels of methylmercury (MeHg). We studied fish–MeHg exposure (total hair-Hg, HHg) as a determinant ...of neurocognitive scores of children living in two geographically distant, culturally distinct and isolated poor communities of non-urban environments: Amazonian riverines (Riparians,
n
=
38) of the Puruzinho Lake community in the Rio Madeira Basin and rural agrarians from Iúna, Espírito Santo (Agrarians,
n
=
32). Nutritional status was estimated by anthropometry (Z-scores) and individual cognitive abilities were assessed by the Wechsler Intelligence Scale for Children-III (WISC-III) and the Human Figure Drawings (HFD), both validated versions for Brazilian children. Anthropometric assessment showed slightly elevated Z-scores for the Agrarian children (not statistically significant) but median HHg concentrations were 14.4 and 0.25
μg
g
−1 respectively for Riparian and Agrarian children (
p
=
0.000). Despite paradoxical MeHg exposures, both groups showed comparable HFD scores but very poor performance in WISC-III test battery; median of sum of WISC-III subtests scores (ΣTOT) were 17.9 and 28.6 (
p
<
0.000) for Riparian and Agrarian children, respectively (percentage scale). Spearman correlation between nutritional status (attained growth) and psychometric scores were statistically significant between height-for-age Z-score and Object Assembly subtest (
r
=
0.269;
p
=
0.043), ΣTOT (
r
=
0.319;
p
=
0.016), Performance-IQ (
r
=
0.311;
p
=
0.019) and Perceptual Organization Index scores (
r
=
0.302;
p
=
0.023). In these isolated communities there are stronger determinants of neurocognitive poor performance than MeHg exposure. Global strategies for reducing human exposure to MeHg by curtailing fish consumption are unrealistic options for riverine subsistence populations and are not justifiable to prevent low cognitive scores.
Highlights • Effectiveness of influenza vaccines was evaluated in Spain in the 2014–2015 season. • Inpatient and outpatient cases with confirmed influenza were the outcome variable. • The overall ...effect of the influenza subunit vaccine in the current season was low. • Split influenza vaccine in the two previous seasons showed considerable protection. • The results suggest interference between both vaccine types.
The dependence of f0(980) production on the final-state charged-particle multiplicity in p–Pb collisions at $\sqrt{s_{NN}}$= 5.02 TeV is reported. The production of f0(980) is measured with the ALICE ...detector via the f0(980) → π+π– decay channel in a midrapidity region of –0.5 < y < 0. Particle yield ratios of f0(980) to π and K*(892)0 are found to be decreasing with increasing charged-particle multiplicity. The magnitude of the suppression of the f0(980)/π and f0(980)/K*(892)0 yield ratios is found to be dependent on the transverse momentum pT, suggesting different mechanisms responsible for the measured effects. Furthermore, the nuclear modification factor QpPb of f0(980) is measured in various multiplicity ranges. The QpPb shows a strong suppression of the f0(980) production in the pT region up to about 4 GeV/c. The results on the particle yield ratios and QpPb for f0(980) may help to understand the late hadronic phase in p–Pb collisions and the nature of the internal structure of f0(980) particle.
A
bstract
The measurement of the production of charm jets, identified by the presence of a D
0
meson in the jet constituents, is presented in proton–proton collisions at centre-of-mass energies of
$$ ...\sqrt{s} $$
s
= 5.02 and 13 TeV with the ALICE detector at the CERN LHC. The D
0
mesons were reconstructed from their hadronic decay D
0
→ K
−
π
+
and the respective charge conjugate. Jets were reconstructed from D
0
-meson candidates and charged particles using the anti-
k
T
algorithm, in the jet transverse momentum range 5
< p
T
,
chjet
<
50 GeV/
c
, pseudorapidity |
η
jet
|
<
0
.
9 −
R
, and with the jet resolution parameters
R
= 0
.
2
,
0
.
4
,
0
.
6. The distribution of the jet momentum fraction carried by a D
0
meson along the jet axis
$$ \left({z}_{\Big\Vert}^{\textrm{ch}}\right) $$
z
‖
ch
was measured in the range 0
.
4
<
$$ {z}_{\Big\Vert}^{\textrm{ch}} $$
z
‖
ch
<
1
.
0 in four ranges of the jet transverse momentum. Comparisons of results for different collision energies and jet resolution parameters are also presented. The measurements are compared to predictions from Monte Carlo event generators based on leading-order and next-to-leading-order perturbative quantum chromodynamics calculations. A generally good description of the main features of the data is obtained in spite of a few discrepancies at low
p
T
,
chjet
. Measurements were also done for
R
= 0
.
3 at
$$ \sqrt{s} $$
s
= 5
.
02 and are shown along with their comparisons to theoretical predictions in an appendix to this paper.
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