It has been demonstrated that supplementation with the two main omega 3 polyunsaturated fatty acids (ω3 FAs), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), leads to modifications in ...the cardiac physiology. ω3 FAs can affect the membrane's lipid composition, as well as proteins' location and/or function. The Na+/H+ exchanger (NHE1) is an integral membrane protein involved in the maintenance of intracellular pH and its hyperactivity has been associated with the development of various cardiovascular diseases such as cardiac hypertrophy.
Our aim was to determine the effect of ω3 FAs on systolic blood pressure (SBP), lipid profiles, NHE1 activity, and cardiac function in spontaneously hypertensive rats (SHR) using Wistar rats (W) as normotensive control. After weaning, the rats received orally ω3 FAs (200 mg/kg body mass/day/ 4 months). We measured SBP, lipid profiles, and different echocardiography parameters, which were used to calculate cardiac hypertrophy index, systolic function, and ventricular geometry. The rats were sacrificed, and ventricular cardiomyocytes were obtained to measure NHE1 activity.
While the treatment with ω3 FAs did not affect the SBP, lipid analysis of plasma revealed a significant decrease in omega-6/omega-3 ratio, correlated with a significant reduction in left ventricular mass index in SHR.
The NHE1 activity was significantly higher in SHR compared with W. While in W the NHE1 activity was similar in both groups, a significant decrease in NHE1 activity was detected in SHRs supplemented with ω3 FAs, reaching values comparable with W. Altogether, these findings revealed that diet supplementation with ω3 FAs since early age prevents the development of cardiac hypertrophy in SHR, perhaps by decreasing NHE1 activity, without altering hemodynamic overload.
•The early and long-term administration of omega-3 fatty acids in SHR:•Does not modify the SBP.•Prevents the development of cardiac hypertrophy.•Avoids NHE1 hyperactivation characteristic of hypertrophied myocardium.•Decreases omega- 6/omega- 3 ratio in plasma.
Background
Fire scars are the primary source of physical evidence used to date past fires around the world, and to estimate parameters of historical fire regimes and fire-climate relationships. ...Despite an increase in studies about historical fire regimes and the relationship between fire and climate, these studies are still limited for Mexican forests. Our goal was to characterize the historical fire regime in two sites with different elevations, to assess changes in fire frequency, and to determine the relationship between fire regimes and climate patterns in a conifer-dominated forest in the Upper Nazas watershed of the Sierra Madre Occidental, Mexico. We were able to cross-date 50 fire-scarred samples of
Pinus arizonica
Engelm.,
P. strobiformis
Engelm.,
P. teocote
Schlecht. & Cham.,
P. durangensis
Martínez, and
Pseudotsuga menziesii
(Mirb.) Franco and identify a total of 596 fire scars.
Results
Evidences are compelling evidences on forest fires occurred frequently in the study area, starting in the mid eighteenth century and through the mid twentieth century. The season of fire occurrence was determined for 560 (94%) fire scars. Most fire scars at both of our sampling locations, found at low and high elevation sites, occurred in the spring (525, 93.8%) and only 6.2% occurred in the summer. The mean fire interval and Weibull median fire interval values were < 10 years for all fire-scar filter (all samples, ≥10% and ≥ 25%), and the average per-sample fire interval was < 25 years.
Conclusions
Our results suggest fire frequency has changed over time at our study site, becoming less common and less extensive since the 1950s. In addition, extensive fires occurred in dry years as indicated by low precipitation, negative NIÑO 3 Sea Surface Temperature (SST) values, and negative Palmer Drought Severity Index (PDSI) values. Fire frequencies must be maintained within the amplitude of their historical regime, with the objective of reducing the risk of severe fires and preserving ecological and hydrological benefits in the watershed.
Abstract The production yields of the Σ(1385) ± and Ξ(1530)0 resonances are measured in pp collisions at s $$ \sqrt{s} $$ = 13 TeV with ALICE. The measurements are performed as a function of the ...charged-particle multiplicity ⟨dN ch /dη⟩, which is related to the energy density produced in the collision. The results include transverse momentum (p T) distributions, p T-integrated yields, mean transverse momenta of Σ(1385) ± and Ξ(1530)0, as well as ratios of the p T-integrated resonance yields relative to yields of other hadron species. The Σ(1385) ± /π ± and Ξ(1530)0 /π ± yield ratios are consistent with the trend of the enhancement of strangeness production from low to high multiplicity pp collisions, which was previously observed for strange and multi-strange baryons. The yield ratio between the measured resonances and the long-lived baryons with the same strangeness content exhibits a hint of a mild increasing trend at low multiplicity, despite too large uncertainties to exclude the flat behaviour. The results are compared with predictions from models such as EPOS-LHC and PYTHIA 8 with Rope shoving. The latter provides the best description of the multiplicity dependence of the Σ(1385) ± and Ξ(1530)0 production in pp collisions at s $$ \sqrt{s} $$ = 13 TeV.
Abstract The ALICE Collaboration reports a search for jet quenching effects in high-multiplicity (HM) proton-proton collisions at s $$ \sqrt{s} $$ = 13 TeV, using the semi-inclusive ...azimuthal-difference distribution ∆φ of charged-particle jets recoiling from a high transverse momentum (high-p T,trig) trigger hadron. Jet quenching may broaden the ∆φ distribution measured in HM events compared to that in minimum bias (MB) events. The measurement employs a p T,trig-differential observable for data-driven suppression of the contribution of multiple partonic interactions, which is the dominant background. While azimuthal broadening is indeed observed in HM compared to MB events, similar broadening for HM events is observed for simulations based on the PYTHIA 8 Monte Carlo generator, which does not incorporate jet quenching. Detailed analysis of these data and simulations show that the azimuthal broadening is due to bias of the HM selection towards events with multiple jets in the final state. The identification of this bias has implications for all jet quenching searches where selection is made on the event activity.
Abstract Results on the transverse spherocity dependence of light-flavor particle production (π, K, p, ϕ, K*0, K S 0 $$ {\textrm{K}}_{\textrm{S}}^0 $$ , Λ, Ξ) at midrapidity in high-multiplicity pp ...collisions at s $$ \sqrt{s} $$ = 13 TeV were obtained with the ALICE apparatus. The transverse spherocity estimator S O p T = 1 $$ \left({S}_{\textrm{O}}^{p_{\textrm{T}}=1}\right) $$ categorizes events by their azimuthal topology. Utilizing narrow selections on S O p T = 1 $$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$ , it is possible to contrast particle production in collisions dominated by many soft initial interactions with that observed in collisions dominated by one or more hard scatterings. Results are reported for two multiplicity estimators covering different pseudorapidity regions. The S O p T = 1 $$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$ estimator is found to effectively constrain the hardness of the events when the midrapidity (|η| < 0.8) estimator is used. The production rates of strange particles are found to be slightly higher for soft isotropic topologies, and severely suppressed in hard jet-like topologies. These effects are more pronounced for hadrons with larger mass and strangeness content, and observed when the topological selection is done within a narrow multiplicity interval. This demonstrates that an important aspect of the universal scaling of strangeness enhancement with final-state multiplicity is that high-multiplicity collisions are dominated by soft, isotropic processes. On the contrary, strangeness production in events with jet-like processes is significantly reduced. The results presented in this article are compared with several QCD-inspired Monte Carlo event generators. Models that incorporate a two-component phenomenology, either through mechanisms accounting for string density, or thermal production, are able to describe the observed strangeness enhancement as a function of S O p T = 1 $$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$ .
Abstract Measurements of inclusive charged-particle jet production in pp and p-Pb collisions at center-of-mass energy per nucleon-nucleon collision s NN $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV and ...the corresponding nuclear modification factor R pPb ch jet $$ {R}_{\textrm{pPb}}^{\textrm{ch}\ \textrm{jet}} $$ are presented, using data collected with the ALICE detector at the LHC. Jets are reconstructed in the central rapidity region |η jet| < 0.5 from charged particles using the anti-k T algorithm with resolution parameters R = 0.2, 0.3, and 0.4. The p T-differential inclusive production cross section of charged-particle jets, as well as the corresponding cross section ratios, are reported for pp and p-Pb collisions in the transverse momentum range 10 < p T , jet ch $$ {p}_{\textrm{T},\textrm{jet}}^{\textrm{ch}} $$ < 140 GeV/c and 10 < p T , jet ch $$ {p}_{\textrm{T},\textrm{jet}}^{\textrm{ch}} $$ < 160 GeV/c, respectively, together with the nuclear modification factor R pPb ch jet $$ {R}_{\textrm{pPb}}^{\textrm{ch}\ \textrm{jet}} $$ in the range 10 < p T , jet ch $$ {p}_{\textrm{T},\textrm{jet}}^{\textrm{ch}} $$ < 140 GeV/c. The analysis extends the p T range of the previously-reported charged-particle jet measurements by the ALICE Collaboration. The nuclear modification factor is found to be consistent with one and independent of the jet resolution parameter with the improved precision of this study, indicating that the possible influence of cold nuclear matter effects on the production cross section of charged-particle jets in p-Pb collisions at s NN $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV is smaller than the current precision. The obtained results are in agreement with other minimum bias jet measurements available for RHIC and LHC energies, and are well reproduced by the NLO perturbative QCD Powheg calculations with parton shower provided by Pythia8 as well as by Jetscape simulations.
Abstract Long- and short-range correlations for pairs of charged particles are studied via two-particle angular correlations in pp collisions at s $$ \sqrt{s} $$ = 13 TeV and p–Pb collisions at s NN ...$$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV. The correlation functions are measured as a function of relative azimuthal angle ∆φ and pseudorapidity separation ∆η for pairs of primary charged particles within the pseudorapidity interval |η| < 0.9 and the transverse-momentum interval 1 < p T < 4 GeV/c. Flow coefficients are extracted for the long-range correlations (1.6 < |∆η| < 1.8) in various high-multiplicity event classes using the low-multiplicity template fit method. The method is used to subtract the enhanced yield of away-side jet fragments in high-multiplicity events. These results show decreasing flow signals toward lower multiplicity events. Furthermore, the flow coefficients for events with hard probes, such as jets or leading particles, do not exhibit any significant changes compared to those obtained from high-multiplicity events without any specific event selection criteria. The results are compared with hydrodynamic-model calculations, and it is found that a better understanding of the initial conditions is necessary to describe the results, particularly for low-multiplicity events.
Abstract The transverse momentum (p T) and centrality dependence of the nuclear modification factor R AA of prompt and non-prompt J/ψ, the latter originating from the weak decays of beauty hadrons, ...have been measured by the ALICE collaboration in Pb–Pb collisions at s NN $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV. The measurements are carried out through the e+e − decay channel at midrapidity (|y| < 0.9) in the transverse momentum region 1.5 < p T < 10 GeV/c. Both prompt and non-prompt J/ψ measurements indicate a significant suppression for p T > 5 GeV/c, which becomes stronger with increasing collision centrality. The results are consistent with similar LHC measurements in the overlapping p T intervals, and cover the kinematic region down to p T = 1.5 GeV/c at midrapidity, not accessible by other LHC experiments. The suppression of prompt J/ψ in central and semicentral collisions exhibits a decreasing trend towards lower transverse momentum, described within uncertainties by models implementing J/ψ production from recombination of c and c ¯ $$ \overline{\textrm{c}} $$ quarks produced independently in different partonic scatterings. At high transverse momentum, transport models including quarkonium dissociation are able to describe the suppression for prompt J/ψ. For non-prompt J/ψ, the suppression predicted by models including both collisional and radiative processes for the computation of the beauty-quark energy loss inside the quark-gluon plasma is consistent with measurements within uncertainties.
Abstract Correlations in azimuthal angle extending over a long range in pseudorapidity between particles, usually called the “ridge” phenomenon, were discovered in heavy-ion collisions, and later ...found in pp and p–Pb collisions. In large systems, they are thought to arise from the expansion (collective flow) of the produced particles. Extending these measurements over a wider range in pseudorapidity and final-state particle multiplicity is important to understand better the origin of these long-range correlations in small collision systems. In this Letter, measurements of the long-range correlations in p–Pb collisions at s NN $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV are extended to a pseudorapidity gap of ∆η ~ 8 between particles using the ALICE forward multiplicity detectors. After suppressing non-flow correlations, e.g., from jet and resonance decays, the ridge structure is observed to persist up to a very large gap of ∆η ~ 8 for the first time in p–Pb collisions. This shows that the collective flow-like correlations extend over an extensive pseudorapidity range also in small collision systems such as p–Pb collisions. The pseudorapidity dependence of the second-order anisotropic flow coefficient, v 2(η), is extracted from the long-range correlations. The v 2(η) results are presented for a wide pseudorapidity range of –3.1 < η < 4.8 in various centrality classes in p–Pb collisions. To gain a comprehensive understanding of the source of anisotropic flow in small collision systems, the v 2(η) measurements are compared with hydrodynamic and transport model calculations. The comparison suggests that the final-state interactions play a dominant role in developing the anisotropic flow in small collision systems.
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