Spatio-temporal variability of urban particulate matter using GIS: a lesson from COVID-19 restrictions

BACKGROUND AND OBJECTIVES: Air pollution and its associated health impacts have become a major concern worldwide, particularly in developing countries. Anthropogenic activities were significantly reduced during the COVID-19 pandemic, allowing for the opportunity for source reduction of air pollutants. A number of studies have been conducted in Dhaka, but most of them are concentrated on a single ground-monitoring station, making it impossible to draw a comprehensive pollution scenario for the entire city. In contrast, this study evaluated the spatio-temporal changes of urban Particulate Matters (PM) in 70 locations from five different land use categories. Hence, this study investigated the influence of the COVID-19 pandemic on PM1 (aerodynamic diameter ≤1 µm), PM2.5 (aerodynamic diameter ≤2.5 µm) and PM10 (aerodynamic diameter ≤10 µm) concentration during three specific time frames: November 2019 (Pre-lockdown), April 2020 (During lockdown), and November 2020 (Post-lockdown).METHODS: The data were collected through portable air quality meter (AEROQUAL 500) during lockdown (April 2020) and post-lockdown (November 2020) period.  Data set of pre-lockdowns (November 2019) was collected from Center for Atmospheric Pollution Studies (CAPS). The Tukey’s Post Hoc Multiple Comparison Test was conducted using Statistical Package for the Social Sciences (SPSSv26) to address the significant changes in air quality between the periods. Additionally, the GIS (Geographical Information System) platform was used to see the spatial and temporal variations of PMs over the city.FINDINGS: The study found that average ground level PM1, PM2.5 and PM10 concentration reduced by 75.1, 75.4, 69.6% and 41.1, 32.6, 29.2% respectively during lockdown compared to pre-lockdown and post-lockdown periods. Moreover, the reduction during lockdown was significant at α=0.05 level. The highest reduction was seen in residential areas from the pre-lockdown to lockdown period, whereas in the lockdown to post-lockdown phase that was found in the industrial areas. Interestingly, the northern part of Dhaka city was less polluted than the southern part in all three studied periods. Besides, the Dhaka city dwellers enjoyed comparatively good quality air in lockdown.CONCLUSION: This study suggested that land use-based source apportionment is required to eliminate the particulate concentration from Dhaka city. Besides, 24 hours continuous data is also important to understand the interaction between particulate concentration and climatic forces. Promoting cleaner transportation options, such as electric vehicles and public transportation is recommended as a means of reducing vehicle emissions. Furthermore, governments could consider implementing emissions regulations, setting limits on emissions, or mandating the use of cleaner fuels and technologies to reduce industrial pollution

Fine structure in the azimuthal transverse momentum correlations at sNN=200\sqrt{s_{NN}}=200 GeV using the event shape analysis

The experimental results on transverse momentum azimuthal hadron correlations at RHIC have opened a rich field for parton energy loss analysis in heavy-ion collisions. Recently, a considerable amount of work has beendevoted to study the shapes of the ``away-side'' jet which exhibit an interesting and unexpected ``double hump'' structure not observed in the analogous treatment of $pp$ data. Driven by the possibility that the latter result might just mean that such structure exists already in the case of $pp$ collisions, but that its relative intensity could be small, here we use the Event Shape Analysis to show that it is possible to identify and select well defined event topologies in $pp$ collisions, among which, a double hump structure for the away-side jet emerges. Using two shape parameters, the sphericity in the transverse plane and the recoil to analyze a sample of PYTHIA generated $pp$ collisions at $\sqrt{s_{NN}}=200$ GeV, we show that this structure corresponds to two jets emitted in the backward hemisphere. Finally, we show that Q-PYTHIA qualitatively reproduces the decrease in the yield of dijet events and the increase of the double hump structure in the away side observed in heavy ion collisions. The implications for the treatment of parton energy loss in heavy-ion collisions are discussedComment: 6 pages, 7 fugures: One figure was changed, references were added. This version will appear in Eur. Phys. J.

Evaluation of anti-nociceptive and anti-inflammatory activities of Piper sylvaticum (Roxb.) stem by experimental and computational approaches

Piper sylvaticum Roxb., (Family: Piperaceae), commonly known as pahaari peepal, is used in traditional medicine for the treatment of rheumatic pain, headache, asthma, chronic cough, diarrhea, and wounds. To provide scientific proof for its traditional use, the present study was designed to investigate the antinociceptive and anti-inflammatory properties of methanol extract of P. sylvaticum stem (MEPSS) in pain models. Additionally, computational studies viz. molecular docking, ADME and toxicological property predictions were performed to identify the potent phytochemicals of this plant for antinociceptive and anti-inflammatory activities with good oral bioavailability and safety features. Quantitative phytochemical analysis of MEPSS was performed using established protocols. The antinociceptive activity was determined using acetic acid and formalin test in mice at the doses of 200 and 400 mg/kg while paw edema induced by carrageenan used for anti-inflammatory activity. Molecular docking study was performed by Schrödinger Maestro 10.1 whereas the SwissADME and admetSAR were used for ADME and toxicity prediction respectively. The total phenolic and flavonoid contents of MEPSS were 93.39 and 53.74 mg gallic acid and quercetin equivalent/g of extract respectively. The methanol extract exhibited significant and dose-dependent antinociceptive and anti-inflammatory effects in experimental pain models. Also, our docking study showed that piperine, piperlonguminine, and sylvamide have the best binding affinities to cyclooxygenase enzymes with good ADME/T properties. This study confirmed that MEPSS possess significant antinociceptive and anti-inflammatory activities which could be due to the presence of phytochemicals and three bioactive compounds (piperine, piperlonguminine, and sylvamide) were found to be most effective in computational studies.</p

Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

We present first measurements of the evolution of the differential transverse momentum correlation function, {\it C}, with collision centrality in Au+Au interactions at $\sqrt{s_{NN}} = 200$ GeV. {\it C} exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations previously reported. We use the observed longitudinal broadening of the near-side peak of {\it C} with increasing centrality to estimate the ratio of the shear viscosity to entropy density, $\eta/s$, of the matter formed in central Au+Au interactions. We obtain an upper limit estimate of $\eta/s$ that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.

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

The inclusive transverse momentum ($p_{\rm T}$) distributions of primary charged particles are measured in the pseudo-rapidity range $|\eta|<0.8$ as a function of event centrality in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}=2.76$ TeV with ALICE at the LHC. The data are presented in the $p_{\rm T}$ range $0.15<p_{\rm T}<50$ GeV/$c$ for nine centrality intervals from 70-80% to 0-5%. The Pb-Pb spectra are presented in terms of the nuclear modification factor $R_{\rm{AA}}$ using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-$p_{\rm T}$ particles strongly depends on event centrality. In central collisions (0-5%) the yield is most suppressed with $R_{\rm{AA}}\approx0.13$ at $p_{\rm T}=6$-7 GeV/$c$. Above $p_{\rm T}=7$ GeV/$c$, there is a significant rise in the nuclear modification factor, which reaches $R_{\rm{AA}} \approx0.4$ for $p_{\rm T}>30$ GeV/$c$. In peripheral collisions (70-80%), the suppression is weaker with $R_{\rm{AA}} \approx 0.7$ almost independently of $p_{\rm T}$. The measured nuclear modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/284

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV

The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.Comment: Submitted to Physics Letters

Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV

A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femtobarns. Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO

Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV

Isolated photon production is measured in proton-proton and lead-lead collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80 GeV with the CMS detector at the LHC. The measured ET spectra are found to be in good agreement with next-to-leading-order perturbative QCD predictions. The ratio of PbPb to pp isolated photon ET-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities.Comment: Submitted to Physics Letters