The Cyprus Institute

About: The Cyprus Institute is a other organization based out in Nicosia, Cyprus. It is known for research contribution in the topics: Aerosol & Environmental science. The organization has 418 authors who have published 1252 publications receiving 32586 citations.

Economic crisis detected from space: Air quality observations over Athens/Greece

Abstract: Received 30 November 2012; accepted 24 December 2012. [1] Using both satellite observations of tropospheric NO2 columns and a number of economic metrics, we investigate the impact of the economic crisis (from 2008 onward) on air quality over Greece, and Athens in particular. The multiannual analysis shows that NO2 columns over Athens have been significantly reduced in the range 30–40%. This decline is further supported by surface measurements of atmospheric NO2 mixing ratios. Additionally, the declining local concentrations of NO, CO, and SO2 are associated with an increase in ozone due to reduced titration by NO. In particular, regression analysis revealed that the reduction of NO2 (0.3 � 0.2ppbv y � 1 )a nd SO 2 (0.2 � 0.1ppbv y � 1 ) during the period 2000–2007, significantly accelerated during the economic crisis period (from 2008 onward), reaching 2.3 � 0.2ppbv y � 1 and 0.7 � 0.1ppbv y � 1 , respectively. The strong correlations between pollutant concentrations and economic indicators show that the economic recession has resulted in proportionally lower levels of pollutants in large parts of Greece. Citation: Vrekoussis, M., A. Richter, A. Hilboll, J. P. Burrows, E. Gerasopoulos, J. Lelieveld, L. Barrie, C. Zerefos, and N. Mihalopoulos (2013), Economic crisis detected from space: Air quality observations over Athens/Greece, Geophys. Res. Lett., 40,

Nucleon axial, tensor, and scalar charges and σ -terms in lattice QCD

Abstract: We determine the nucleon axial, scalar and tensor charges within lattice quantum chromodynamics including all contributions from valence and sea quarks. We analyze three gauge ensembles simulated within the twisted mass formulation at approximately physical value of the pion mass. Two of these ensembles are simulated with two dynamical light quarks and lattice spacing $a=0.094\text{ }\text{ }\mathrm{fm}$ and the third with $a=0.08\text{ }\text{ }\mathrm{fm}$ includes in addition the strange and charm quarks in the sea. After comparing the results among these three ensembles, we quote as final values our most accurate analysis using the latter ensemble. For the nucleon isovector axial charge we find 1.286(23) in agreement with the experimental value. We provide the flavor decomposition of the intrinsic spin $\frac{1}{2}\mathrm{\ensuremath{\Delta}}{\mathrm{\ensuremath{\Sigma}}}^{q}$ carried by quarks in the nucleon obtaining for the up, down, strange and charm quarks $\frac{1}{2}\mathrm{\ensuremath{\Delta}}{\mathrm{\ensuremath{\Sigma}}}^{u}=0.431(8)$, $\frac{1}{2}\mathrm{\ensuremath{\Delta}}{\mathrm{\ensuremath{\Sigma}}}^{d}=\ensuremath{-}0.212(8)$, $\frac{1}{2}\mathrm{\ensuremath{\Delta}}{\mathrm{\ensuremath{\Sigma}}}^{s}=\ensuremath{-}0.023(4)$ and $\frac{1}{2}\mathrm{\ensuremath{\Delta}}{\mathrm{\ensuremath{\Sigma}}}^{c}=\ensuremath{-}0.005(2)$, respectively. The corresponding values of the tensor and scalar charges for each quark flavor are also evaluated providing valuable input for experimental searches for beyond the standard model physics. In addition, we extract the nucleon $\ensuremath{\sigma}$-terms and find for the light quark content ${\ensuremath{\sigma}}_{\ensuremath{\pi}N}=41.6(3.8)\text{ }\text{ }\mathrm{MeV}$ and for the strange ${\ensuremath{\sigma}}_{s}=45.6(6.2)\text{ }\text{ }\mathrm{MeV}$. The y-parameter that is used in phenomenological studies we find $y=0.078(7)$.

COVID-19 lockdowns cause global air pollution declines with implications for public health risk

Abstract: The lockdown response to COVID-19 has caused an unprecedented reduction in global economic activity. We test the hypothesis that this has reduced tropospheric and ground-level air pollution concentrations using satellite data and a network of >10,000 air quality stations. After accounting for the effects of meteorological variability, we find remarkable declines in ground-level nitrogen dioxide (NO2: −29 % with 95% confidence interval −44% to −13%), ozone (O3: −11%; −20% to −2%) and fine particulate matter (PM2.5: −9%; −28% to 10%) during the first two weeks of lockdown (n = 27 countries). These results are largely mirrored by satellite measures of the troposphere although long-distance transport of PM2.5 resulted in more heterogeneous changes relative to NO2. Pollutant anomalies were related to short-term health outcomes using empirical exposure-response functions. We estimate that there was a net total of 7400 (340 to 14600) premature deaths and 6600 (4900 to 7900) pediatric asthma cases avoided during two weeks post-lockdown. In China and India alone, the PM2.5-related avoided premature mortality was 1400 (1100 to 1700) and 5300 (1000 to 11700), respectively. Assuming that the lockdown-induced deviations in pollutant concentrations are maintained for the duration of 2020, we estimate 0.78 (0.09 to 1.5) million premature deaths and 1.6 (0.8 to 2) million pediatric asthma cases could be avoided globally. While the state of global lockdown is not sustainable, these findings illustrate the potential health benefits gained from reducing “business as usual” air pollutant emissions from economic activities. Explore trends here: www.covid-19-pollution.zsv.co.za Significance statement The global response to the COVID-19 pandemic has resulted in unprecedented reductions in economic activity. We find that lockdown events have reduced air pollution levels by approximately 20% across 27 countries. The reduced air pollution levels come with a substantial health co-benefit in terms of avoided premature deaths and pediatric asthma cases that accompanied the COVID-19 containment measures.

Low-lying baryon spectrum with two dynamical twisted mass fermions

Abstract: The masses of the low-lying baryons are evaluated using two degenerate flavors of twisted mass sea quarks corresponding to pseudoscalar masses in the range of about 270\char21{}500 MeV. The strange valence quark mass is tuned to reproduce the mass of the kaon in the physical limit. The tree-level Symanzik improved gauge action is employed. We use lattices of spatial size 2.1 and 2.7 fm at two values of the lattice spacing with ${r}_{0}/a=5.22(2)$ and ${r}_{0}/a=6.61(3)$. We check for both finite volume and cutoff effects on the baryon masses. We performed a detailed study of the chiral extrapolation of the octet and decuplet masses using SU(2) $\ensuremath{\chi}\mathrm{PT}$. The lattice spacings determined using the nucleon mass at the physical point are consistent with the values extracted using the pion decay constant. We examine the issue of isospin symmetry breaking for the octet and decuplet baryons and its dependence on the lattice spacing. We show that in the continuum limit isospin breaking is consistent with zero, as expected. The baryon masses that we find after taking the continuum limit and extrapolating to the physical limit are in good agreement with experiment.

Modelling the global atmospheric transport and deposition of radionuclides from the Fukushima Dai-ichi nuclear accident

Abstract: . We modeled the global atmospheric dispersion and deposition of radionuclides released from the Fukushima Dai-ichi nuclear power plant accident. The EMAC atmospheric chemistry – general circulation model was used, with circulation dynamics nudged towards ERA-Interim reanalysis data. We applied a resolution of approximately 0.5 degrees in latitude and longitude (T255). The model accounts for emissions and transport of the radioactive isotopes 131 I and 137 Cs, and removal processes through precipitation, particle sedimentation and dry deposition. In addition, we simulated the release of 133 Xe, a noble gas that can be regarded as a passive transport tracer of contaminated air. The source terms are based on Chino et al. (2011) and Stohl et al. (2012); especially the emission estimates of 131 I are associated with a high degree of uncertainty. The calculated concentrations have been compared to station observations by the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO). We calculated that about 80% of the radioactivity from Fukushima which was released to the atmosphere deposited into the Pacific Ocean. In Japan a large inhabited land area was contaminated by more than 40 kBq m -2 . We also estimated the inhalation and 50-year dose by 137 Cs, 134 Cs and 131 I to which the people in Japan are exposed.