scispace - formally typeset
Search or ask a question

Showing papers by "The Cyprus Institute published in 2017"


Journal ArticleDOI
TL;DR: In this article, for the first time, the non-perturbative renormalization for unpolarized, helicity and transversity quasi-PDFs in an RI-scheme was presented.

176 citations


Journal ArticleDOI
TL;DR: In this paper, a global chemistry-climate model has been used to study the impacts of pollutants released by agriculture on fine-particulate matter (PM2.5), with a focus on Europe, North America, East and South Asia.
Abstract: . A global chemistry-climate model has been used to study the impacts of pollutants released by agriculture on fine-particulate matter (PM2.5), with a focus on Europe, North America, East and South Asia. Simulations reveal that a relatively strong reduction in PM2.5 levels can be achieved by decreasing agricultural emissions, notably of ammonia (NH3) released from fertilizer use and animal husbandry. The absolute impact on PM2.5 reduction is strongest in East Asia, even for small emission decreases. Conversely, over Europe and North America, aerosol formation is not immediately limited by the availability of ammonia. Nevertheless, reduction of NH3 can also substantially decrease PM2.5 concentrations over the latter regions, especially when emissions are abated systematically. Our results document how reduction of agricultural emissions decreases aerosol pH due to the depletion of aerosol ammonium, which affects particle liquid phase and heterogeneous chemistry. Further, it is shown that a 50 % reduction of agricultural emissions could prevent the mortality attributable to air pollution by ∼ 250 000 people yr−1 worldwide, amounting to reductions of 30, 19, 8 and 3 % over North America, Europe, East and South Asia, respectively. A theoretical 100 % reduction could even reduce the number of deaths globally by about 800 000 per year.

146 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the determinants of resilience to economic crisis across European regions, and assessed regional economic resilience based on employment changes during 2008-2013, while socioeconomic determinants were analysed pre-crisis (2002-2007).
Abstract: The impact of the economic crisis has been highly asymmetric across the European regions. The objective of this paper is to investigate the determinants of resilience to economic crisis across European regions. Regional economic resilience was assessed based on employment changes during 2008–2013, while socioeconomic determinants were analysed pre-crisis (2002–2007). A highly heterogeneous pattern of resilience was observed within countries, while significant differences were also revealed between the continental northern-central regions and the southern periphery. A multilevel logistic regression model indicated the magnitude of country-effects on the performance of regional employment during crisis periods. Both EU-referenced and country-referenced regional resilience identified the positive effect of accessibility and the negative effect of a large manufacturing sector in the ability of regions to withstand recessionary shocks. Education and economic development level positively affected the re...

142 citations


Journal ArticleDOI
01 Aug 2017
TL;DR: In this article, shift-share and input-output models are combined to explore the resilience of Greek regions to economic crisis, showing that rural regions are more resistant to recessionary shocks than urban regions.
Abstract: Shift-share and input-output models are combined to explore the resilience of Greek regions to economic crisis. Model results indicate that rural regions are more resistant to recessionary shocks than urban regions. The analysis of the space-specific ability of sectors to withstand economic shocks portrayed the resilience of agriculture, while food industry, although its impact overtime declined, managed to increase its employment in seven out of thirteen regions. The tourism sector contracted but showed more resilience in the island regions than in the continental regions. The spatial heterogeneity in the effects of the recessionary shocks re-emphasizes the need for targeted and differentiated regional development policies.

138 citations


Journal ArticleDOI
TL;DR: In this article, the authors provided an analysis of the dependence of the bare unpolarized, helicity, and transversity isovector parton distribution functions (PDFs) from lattice calculations employing (maximally) twisted mass fermions.
Abstract: We provide an analysis of the $x$ dependence of the bare unpolarized, helicity, and transversity isovector parton distribution functions (PDFs) from lattice calculations employing (maximally) twisted mass fermions. The $x$ dependence of the calculated PDFs resembles the one of the phenomenological parameterizations, a feature that makes this approach very promising. Furthermore, we apply momentum smearing for the relevant matrix elements to compute the lattice PDFs and find a large improvement factor when compared to conventional Gaussian smearing. This allows us to extend the lattice computation of the distributions to higher values of the nucleon momentum, which is essential for the prospects of a reliable extraction of the PDFs in the future.

132 citations



Journal ArticleDOI
TL;DR: Within lattice QCD the nucleon spin carried by valence and sea quarks and gluons is determined using an ensemble of gauge configurations with two degenerate light quarks with mass fixed to approximately reproduce the physical pion mass.
Abstract: We determine within lattice QCD the nucleon spin carried by valence and sea quarks and gluons. The calculation is performed using an ensemble of gauge configurations with two degenerate light quarks with mass fixed to approximately reproduce the physical pion mass. We find that the total angular momentum carried by the quarks in the nucleon is ${J}_{u+d+s}=0.408(61{)}_{\text{stat}}(48{)}_{\text{syst}}$ and the gluon contribution is ${J}_{g}=0.133(11{)}_{\text{stat}}(14{)}_{\text{syst}}$, giving a total of ${J}_{N}=0.54(6{)}_{\text{stat}}(5{)}_{\text{syst}}$ that is consistent with the spin sum. For the quark intrinsic spin contribution, we obtain $\frac{1}{2}\mathrm{\ensuremath{\Delta}}{\mathrm{\ensuremath{\Sigma}}}_{u+d+s}=0.201(17{)}_{\text{stat}}(5{)}_{\text{syst}}$. All quantities are given in the modified minimal subtraction scheme at 2 GeV. The quark and gluon momentum fractions are also computed and add up to $⟨x{⟩}_{u+d+s}+⟨x{⟩}_{g}=0.804(121{)}_{\text{stat}}(95{)}_{\text{syst}}+0.267(12{)}_{\text{stat}}(10{)}_{\text{syst}}=1.07(12{)}_{\text{stat}}(10{)}_{\text{syst}}$, thus satisfying the momentum sum.

127 citations


Journal ArticleDOI
TL;DR: In this article, the authors present results on the nucleon axial and induced pseudoscalar form factors using an ensemble of two degenerate twisted mass clover-improved fermions with mass yielding a pion mass of
Abstract: We present results on the nucleon axial and induced pseudoscalar form factors using an ensemble of two degenerate twisted mass clover-improved fermions with mass yielding a pion mass of ${m}_{\ensuremath{\pi}}=130\text{ }\text{ }\mathrm{MeV}$. We evaluate the isovector and the isoscalar, as well as the strange and the charm axial form factors. The disconnected contributions are evaluated using recently developed methods that include deflation of the lower eigenstates, allowing us to extract the isoscalar, strange, and charm axial form factors. We find that the disconnected quark loop contributions are nonzero and particularly large for the induced pseudoscalar form factor.

111 citations


Journal ArticleDOI
TL;DR: The human behaviors and activities besides eating that can generate a flux of particles into the human mouth, the broad range of additional cultural and environmental information that can be obtained through the analysis and contextualisation of this material, and the implications of the additional pathways by which material can become embedded in dental calculus are explored.
Abstract: Dental calculus (mineralized dental plaque) was first recognised as a potentially useful archaeological deposit in the 1970s, though interest in human dental calculus as a resource material has increased sharply in the past few years. The majority of recent research has focused on the retrieval of plant microfossils embedded in its matrix and interpretation of these finds as largely the result of deliberate consumption of plant-derived food. However, while most of the material described in published works does represent food, dental calculus is in fact a "depositional environment" as material can enter the mouth from a range of sources. In this respect, it therefore represents an archaeological deposit that can also contain extensive non-dietary debris. This can comprise a wide variety of cultural and environmental material which reaches the mouth and can become embedded in dental calculus through alternative pathways. Here, we explore the human behaviors and activities besides eating that can generate a flux of particles into the human mouth, the broad range of additional cultural and environmental information that can be obtained through the analysis and contextualisation of this material, and the implications of the additional pathways by which material can become embedded in dental calculus.

98 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed a new approach for the HPC-LEAP joint doctorate program, which is based on the work of the RHIC Physics Fellow Program of the RIKEN BNL Research Center.
Abstract: National Science Foundation [ACI-1053575, PHY-1520996]; RHIC Physics Fellow Program of the RIKEN BNL Research Center; U.S. Department of Energy Office of Nuclear Physics [DE-SC-0011090, DE-FC02-06ER41444]; European Union [642069]; HPC-LEAP joint doctorate program; Office of Science of the U.S. Department of Energy [DE-AC02-05CH11231]

94 citations


Journal ArticleDOI
TL;DR: In this article, a comparison of energy dynamic and quasi-dynamic models with data from smart monitoring systems, indoor and outdoor environment measurements, power consumption and production data is performed to explore the performance gap between energy efficiency prediction in the design phase and measurements' evaluation in operational phase.

Journal ArticleDOI
TL;DR: In this article, the authors applied the recently introduced polarization lidar-photometer networking (POLIPHON) technique for the first time to triple-wavelength polarization LIDAR measurements at 355, 532, and 1064 nm.
Abstract: . We applied the recently introduced polarization lidar–photometer networking (POLIPHON) technique for the first time to triple-wavelength polarization lidar measurements at 355, 532, and 1064 nm. The lidar observations were performed at Barbados during the Saharan Aerosol Long-Range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) in the summer of 2014. The POLIPHON method comprises the traditional lidar technique to separate mineral dust and non-dust backscatter contributions and the new, extended approach to separate even the fine and coarse dust backscatter fractions. We show that the traditional and the advanced method are compatible and lead to a consistent set of dust and non-dust profiles at simplified, less complex aerosol layering and mixing conditions as is the case over the remote tropical Atlantic. To derive dust mass concentration profiles from the lidar observations, trustworthy extinction-to-volume conversion factors for fine, coarse, and total dust are needed and obtained from an updated, extended Aerosol Robotic Network sun photometer data analysis of the correlation between the fine, coarse and total dust volume concentration and the respective fine, coarse, and total dust extinction coefficient for all three laser wavelengths. Conversion factors (total volume to extinction) for pure marine aerosol conditions and continental anthropogenic aerosol situations are presented in addition. As a new feature of the POLIPHON data analysis, the Raman lidar method for particle extinction profiling is used to identify the aerosol type (marine or anthropogenic) of the non-dust aerosol fraction. The full POLIPHON methodology was successfully applied to a SALTRACE case and the results are discussed. We conclude that the 532 nm polarization lidar technique has many advantages in comparison to 355 and 1064 nm polarization lidar approaches and leads to the most robust and accurate POLIPHON products.

Journal ArticleDOI
01 Jan 2017-Geoderma
TL;DR: In this paper, a multiple-trees classification technique, namely Random Forest (RF), was applied to extend predictions from 1:25,000 legacy soil surveys (including WRB soil groups, soil depth and soil texture classes) to the larger area of Cyprus.

Journal ArticleDOI
TL;DR: In this article, a series of near real-time and off-line biomass burning tracers are analyzed during intense wood burning events in Athens, and the suitability of these tracers was evaluated when the prevailing meteorological conditions with low dispersion and deposition mechanisms (low wind speed, absence of precipitation) were associated with high biomass burning emissions at nighttime.

Journal ArticleDOI
TL;DR: In this paper, the effects of climate change on various atmospheric processes are considered throughout this paper, in addition to a dedicated section on temperature and precipitation, and the atmospheric chemistry of the region is increasingly becoming of utmost importance for the area under study.

Journal ArticleDOI
TL;DR: In this article, a statistical analysis of the microclimate variation during monitored hot periods is performed by the analysis of local weather parameters collected from a dedicated meteorological station, and numerical analysis of representative Italian residential buildings is carried out to determine the role of such phenomena on indoor thermal comfort and cooling energy requirements, by considering the consequences arising from heatwaves due to indoor overheating stress.

Journal ArticleDOI
TL;DR: In this article, the authors present an overview of lattice-QCD and global-analysis techniques used to determine unpolarized and polarized proton PDFs and their moments.
Abstract: In the framework of quantum chromodynamics (QCD), parton distribution functions (PDFs) quantify how the momentum and spin of a hadron are divided among its quark and gluon constituents. Two main approaches exist to determine PDFs. The first approach, based on QCD factorization theorems, realizes a QCD analysis of a suitable set of hard-scattering measurements, often using a variety of hadronic observables. The second approach, based on first-principle operator definitions of PDFs, uses lattice QCD to compute directly some PDF-related quantities, such as their moments. Motivated by recent progress in both approaches, in this document we present an overview of lattice-QCD and global-analysis techniques used to determine unpolarized and polarized proton PDFs and their moments. We provide benchmark numbers to validate present and future lattice-QCD calculations and we illustrate how they could be used to reduce the PDF uncertainties in current unpolarized and polarized global analyses. This document represents a first step towards establishing a common language between the two communities, to foster dialogue and to further improve our knowledge of PDFs.

Journal ArticleDOI
TL;DR: In this paper, the light, strange and charm nucleon scalar and tensor charges from lattice QCD were extracted directly at the physical point, and the renormalization was computed nonperturbatively for both isovector and isoscalar quantities.
Abstract: We present results on the light, strange and charm nucleon scalar and tensor charges from lattice QCD, using simulations with Nf=2 flavors of twisted mass clover-improved fermions with a physical value of the pion mass. Both connected and disconnected contributions are included, enabling us to extract the isoscalar, strange and charm charges for the first time directly at the physical point. Furthermore, the renormalization is computed nonperturbatively for both isovector and isoscalar quantities. We investigate excited state effects by analyzing several sink-source time separations and by employing a set of methods to probe ground state dominance. Our final results for the scalar charges are gSu=5.20(42)(15)(12), gSd=4.27(26)(15)(12), gSs=0.33(7)(1)(4), and gSc=0.062(13)(3)(5) and for the tensor charges gTu=0.794(16)(2)(13), gTd=-0.210(10)(2)(13), gTs=0.00032(24)(0), and gTc=0.00062(85)(0) in the MS¯ scheme at 2 GeV. The first error is statistical, the second is the systematic error due to the renormalization and the third the systematic arising from estimating the contamination due to the excited states, when our data are precise enough to probe the first excited state.

Book ChapterDOI
01 Jan 2017
TL;DR: In the Eastern Tropical Pacific (ETP) coral reef biogeography and ecology, a mean increase of 4.2 new species records per locality or an overall increase of 19.2 % in species richness during the past decade was reported.
Abstract: Advances in our knowledge of eastern tropical Pacific (ETP) coral reef biogeography and ecology during the past two decades are briefly reviewed. Fifteen ETP subregions are recognized, including mainland and island localities from the Gulf of California (Mexico) to Rapa Nui (Easter Island, Chile). Updated species lists reveal a mean increase of 4.2 new species records per locality or an overall increase of 19.2 % in species richness during the past decade. The largest increases occurred in tropical mainland Mexico, and in equatorial Costa Rica and Colombia, due mainly to continuing surveys of these under-studied areas. Newly discovered coral communities are also now known from the southern Nicaraguan coastline. To date 47 zooxanthellate scleractinian species have been recorded in the ETP, of which 33 also occur in the central/south Pacific, and 8 are presumed to be ETP endemics. Usually no more than 20–25 zooxanthellate coral species are present at any given locality, with the principal reef-building genera being Pocillopora, Porites, Pavona, and Gardineroseris. This compares with 62–163 species at four of the nearest central/south Pacific localities. Hydrocorals in the genus Millepora also occur in the ETP and are reviewed in the context of their global distributions. Coral community associates engaged in corallivory, bioerosion, and competition for space are noted for several localities. Reef framework construction in the ETP typically occurs at shallow depths (2–8 m) in sheltered habitats or at greater depths (10–30 m) in more exposed areas such as oceanic island settings with high water column light penetration. Generally, eastern Pacific reefs do not reach sea level with the development of drying reef flats, and instead experience brief periods of exposure during extreme low tides or drops in sea level during La Nina events. High rates of mortality during El Nino disturbances have occurred in many ETP equatorial areas, especially in Panama and the Galapagos Islands during the 1980s and 1990s. Remarkably, however, no loss of resident, zooxanthellate scleractinian species has occurred at these sites, and many ETP coral reefs have demonstrated significant recovery from these disturbances during the past two decades.

Journal ArticleDOI
TL;DR: In this article, the masses of low-lying baryons are evaluated using an ensemble with two degenerate light twisted mass clover-improved quarks with mass tuned to reproduce the physical pion mass.
Abstract: The masses of the low-lying baryons are evaluated using an ensemble with two degenerate light twisted mass clover-improved quarks with mass tuned to reproduce the physical pion mass. The Iwasaki improved gluonic action is employed. The coupling constant value corresponds to a lattice spacing of $a=0.0938(3)(2)\text{ }\text{ }\mathrm{fm}$, determined from the nucleon mass. We find that the clover term supresses isospin symmetry breaking as compared to our previous results using ${N}_{f}=2+1+1$ twisted mass fermions. The masses of the hyperons and charmed baryons evaluated using this ensemble are in agreement with the experimental values. We provide predictions for the mass of the doubly charmed ${\mathrm{\ensuremath{\Xi}}}_{cc}^{*}$, as well as of the doubly and triply charmed $\mathrm{\ensuremath{\Omega}}$s that have not yet been determined experimentally.

Journal ArticleDOI
TL;DR: The Global Aerosol Synthesis and Science Project (GASSP) as mentioned in this paper aims to improve the robustness of global aerosol models by combining new methodologies for quantifying model uncertainty, to create an extensive global dataset of aerosol in situ microphysical and chemical measurements, and to assess the uncertainty associated with comparing sparse point measurements with low-resolution models.
Abstract: The largest uncertainty in the historical radiative forcing of climate is caused by changes in aerosol particles due to anthropogenic activity. Sophisticated aerosol microphysics processes have been included in many climate models in an effort to reduce the uncertainty. However, the models are very challenging to evaluate and constrain because they require extensive in situ measurements of the particle size distribution, number concentration, and chemical composition that are not available from global satellite observations. The Global Aerosol Synthesis and Science Project (GASSP) aims to improve the robustness of global aerosol models by combining new methodologies for quantifying model uncertainty, to create an extensive global dataset of aerosol in situ microphysical and chemical measurements, and to develop new ways to assess the uncertainty associated with comparing sparse point measurements with low-resolution models. GASSP has assembled over 45,000 hours of measurements from ships and aircraft as well as data from over 350 ground stations. The measurements have been harmonized into a standardized format that is easily used by modelers and nonspecialist users. Available measurements are extensive, but they are biased to polluted regions of the Northern Hemisphere, leaving large pristine regions and many continental areas poorly sampled. The aerosol radiative forcing uncertainty can be reduced using a rigorous model–data synthesis approach. Nevertheless, our research highlights significant remaining challenges because of the difficulty of constraining many interwoven model uncertainties simultaneously. Although the physical realism of global aerosol models still needs to be improved, the uncertainty in aerosol radiative forcing will be reduced most effectively by systematically and rigorously constraining the models using extensive syntheses of measurements.

Journal ArticleDOI
TL;DR: In this paper, the authors employ the WRF-Chem model to study summertime air pollution and their impact on air quality over the eastern Mediterranean region of Cyprus, where the CYPHEX campaign took place in July 2014.
Abstract: . We employ the WRF-Chem model to study summertime air pollution, the intense photochemical activity and their impact on air quality over the eastern Mediterranean. We utilize three nested domains with horizontal resolutions of 80, 16 and 4 km, with the finest grid focusing on the island of Cyprus, where the CYPHEX campaign took place in July 2014. Anthropogenic emissions are based on the EDGAR HTAP global emission inventory, while dust and biogenic emissions are calculated online. Three simulations utilizing the CBMZ-MOSAIC, MOZART-MOSAIC, and RADM2-MADE/SORGAM gas-phase and aerosol mechanisms are performed. The results are compared with measurements from a dense observational network of 14 ground stations in Cyprus. The model simulates T2 m , Psurf , and WD10 m accurately, with minor differences in WS10 m between model and observations at coastal and mountainous stations attributed to limitations in the representation of the complex topography in the model. It is shown that the south-eastern part of Cyprus is mostly affected by emissions from within the island, under the dominant (60 %) westerly flow during summertime. Clean maritime air from the Mediterranean can reduce concentrations of local air pollutants over the region during westerlies. Ozone concentrations are overestimated by all three mechanisms (9 % ≤ NMB ≤ 23 %) with the smaller mean bias (4.25 ppbV) obtained by the RADM2-MADE/SORGAM mechanism. Differences in ozone concentrations can be attributed to the VOC treatment by the three mechanisms. The diurnal variability of pollution and ozone precursors is not captured (hourly correlation coefficients for O 3 ≤ 0.29). This might be attributed to the underestimation of NO x concentrations by local emissions by up to 50 %. For the fine particulate matter ( PM2.5 ), the lowest mean bias (9 µ g m −3 ) is obtained with the RADM2-MADE/SORGAM mechanism, with overestimates in sulfate and ammonium aerosols. Overestimation of sulfate aerosols by this mechanism may be linked to the SO2 oxidation in clouds. The MOSAIC aerosol mechanism overestimates PM2.5 concentrations by up to 22 µ g m −3 due to a more pronounced dust component compared to the other two mechanisms, mostly influenced by the dust inflow from the global model. We conclude that all three mechanisms are very sensitive to boundary conditions from the global model for both gas-phase and aerosol pollutants, in particular dust and ozone.

Journal ArticleDOI
TL;DR: In this article, a PM2.5-capable aerosol chemical speciation monitor (Q-ACSM) was deployed in urban Nanjing, China, for the first time to measure in situ non-refractory fine particle composition from 20 October to 19 November 2015, along with parallel measurements of submicron aerosol (PM1) species.
Abstract: . A PM2.5-capable aerosol chemical speciation monitor (Q-ACSM) was deployed in urban Nanjing, China, for the first time to measure in situ non-refractory fine particle (NR-PM2.5) composition from 20 October to 19 November 2015, along with parallel measurements of submicron aerosol (PM1) species by a standard Q-ACSM. Our results show that the NR-PM2.5 species (organics, sulfate, nitrate, and ammonium) measured by the PM2.5-Q-ACSM are highly correlated (r2 > 0.9) with those measured by a Sunset Lab OC / EC analyzer and a Monitor for AeRosols and GAses (MARGA). The comparisons between the two Q-ACSMs illustrated similar temporal variations in all NR species between PM1 and PM2.5, yet substantial mass fractions of aerosol species were observed in the size range of 1–2.5 µm. On average, NR-PM1−2.5 contributed 53 % of the total NR-PM2.5, with sulfate and secondary organic aerosols (SOAs) being the two largest contributors (26 and 27 %, respectively). Positive matrix factorization of organic aerosol showed similar temporal variations in both primary and secondary OAs between PM1 and PM2.5, although the mass spectra were slightly different due to more thermal decomposition on the capture vaporizer of the PM2.5-Q-ACSM. We observed an enhancement of SOA under high relative humidity conditions, which is associated with simultaneous increases in aerosol pH, gas-phase species (NO2, SO2, and NH3) concentrations and aerosol water content driven by secondary inorganic aerosols. These results likely indicate an enhanced reactive uptake of SOA precursors upon aqueous particles. Therefore, reducing anthropogenic NOx, SO2, and NH3 emissions might not only reduce secondary inorganic aerosols but also the SOA burden during haze episodes in China.

Journal ArticleDOI
TL;DR: In this paper, the performance of different convection and microphysics parameterizations of the weather research and forecasting model at very high horizontal resolutions (12, 4 and 1) was analyzed.

Journal ArticleDOI
TL;DR: In this article, the major chemical composition at four different urban background sites across the country (Paris, Creil, Metz and Lyon) allowed the investigation of spatiotemporal variabilities during a severe and large-scale particulate matter (PM) pollution episode.

Journal ArticleDOI
TL;DR: In this article, the authors present the light-scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, which are located mainly in Europe.
Abstract: This paper presents the light-scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, which are located mainly in Europe. The data include particle light scattering (σsp) and hemispheric backscattering (σbsp) coefficients, scattering Angstrom exponent (SAE), backscatter fraction (BF) and asymmetry parameter (g). An increasing gradient of σsp is observed when moving from remote environments (arctic/mountain) to regional and to urban environments. At a regional level in Europe, σsp also increases when moving from Nordic and Baltic countries and from western Europe to central/eastern Europe, whereas no clear spatial gradient is observed for other station environments. The SAE does not show a clear gradient as a function of the placement of the station. However, a west-to-east-increasing gradient is observed for both regional and mountain placements, suggesting a lower fraction of fine-mode particle in western/south-western Europe compared to central and eastern Europe, where the fine-mode particles dominate the scattering. The g does not show any clear gradient by station placement or geographical location reflecting the complex relationship of this parameter with the physical properties of the aerosol particles. Both the station placement and the geographical location are important factors affecting the intraannual variability. At mountain sites, higher σsp and SAE values are measured in the summer due to the enhanced boundary layer influence and/or new particle-formation episodes. Conversely, the lower horizontal and vertical dispersion during winter leads to higher σsp values at all low-altitude sites in central and eastern Europe compared to summer. These sites also show SAE maxima in the summer (with corresponding g minima). At all sites, both SAE and g show a strong variation with aerosol particle loading. The lowest values of g are always observed together with low σsp values, indicating a larger contribution from particles in the smaller accumulation mode. During periods of high σsp values, the variation of g is less pronounced, whereas the SAE increases or decreases, suggesting changes mostly in the coarse aerosol particle mode rather than in the fine mode. Statistically significant decreasing trends of σsp are observed at 5 out of the 13 stations included in the trend analyses. The total reductions of σsp are consistent with those reported for PM2.5 and PM10 mass concentrations over similar periods across Europe. © Author(s) 2018.

Journal ArticleDOI
TL;DR: In this article, the authors present results on the renormalization functions of the quark field and fermion bilinear with up to one covariant derivative for the twisted mass formulation and the Iwasaki-improved action.
Abstract: We present results on the renormalization functions of the quark field and fermion bilinears with up to one covariant derivative. For the fermion part of the action, we employ the twisted mass formulation with ${N}_{f}=2$ and ${N}_{f}=4$ degenerate dynamical quarks, while in the gluon sector, we use the Iwasaki-improved action. The simulations for ${N}_{f}=4$ have been performed for pion masses in the range of 390--760 MeV and at three values of the lattice spacing, $a$, corresponding to $\ensuremath{\beta}=1.90$, 1.95, 2.10. The ${N}_{f}=2$ action includes a clover term with ${c}_{\mathrm{sw}}=1.57551$ at $\ensuremath{\beta}=2.10$, and three ensembles at different values of ${m}_{\ensuremath{\pi}}$. The evaluation of the renormalization functions is carried out in the ${\mathrm{RI}}^{\ensuremath{'}}$ scheme using a momentum source. The nonperturbative evaluation is complemented with a perturbative computation, which is carried out at one-loop level and to all orders in the lattice spacing, $a$. For each renormalization function computed nonperturbatively, we subtract the corresponding lattice artifacts to all orders in $a$, so that a large part of the cutoff effects is eliminated. The renormalization functions are converted to the $\overline{\mathrm{MS}}$ scheme at a reference energy scale of $\ensuremath{\mu}=2\text{ }\text{ }\mathrm{GeV}$ after taking the chiral limit.

Journal ArticleDOI
TL;DR: In this paper, the low-lying glueball spectrum and various string tensions in SU(N ) lattice gauge theories in 2 + 1 dimensions were calculated and extrapolate the results to the continuum limit.
Abstract: We calculate the low-lying glueball spectrum and various string tensions in SU(N ) lattice gauge theories in 2 + 1 dimensions, and extrapolate the results to the continuum limit. We do so for for the range N ∈ [2, 16] so as to control the N -dependence with a useful precision. We observe a number of striking near-degeneracies in the various J PC sectors of the glueball spectrum, in particular between C = + and C = − states. We calculate the string tensions of flux tubes in a number of representations, and provide evidence that the leading correction to the N -dependence of the k-string tensions is ∝ 1/N rather than ∝ 1/N 2, and that the dominant binding of k fundamental flux tubes into a k-string is via pairwise interactions. We comment on the possible implications of our results for the dynamics of these gauge theories.

Journal ArticleDOI
TL;DR: In this article, an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV was used to derive the nucleon electromagnetic form factors.
Abstract: We present results for the nucleon electromagnetic form factors using an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV. We use multiple sink-source separations and three analysis methods to probe ground-state dominance. We evaluate both the connected and disconnected contributions to the nucleon matrix elements. We find that the disconnected quark loop contributions to the isoscalar matrix elements are small, giving an upper bound of up to 2% of the connected and smaller than its statistical error. We present results for the isovector and isoscalar electric and magnetic Sachs form factors and the corresponding proton and neutron form factors. By fitting the momentum dependence of the form factors to a dipole form or to the $z$ expansion, we extract the nucleon electric and magnetic radii, as well as the magnetic moment. We compare our results to experiment as well as to other recent lattice QCD calculations.

Journal ArticleDOI
TL;DR: In this paper, a wide range of fluxes was observed, ranging from 0.6 to 264'ng'm −2 ˚s −1 ǫ at optimal soil water content (20-30'% of water holding capacity, WHC).
Abstract: . Soil and biological soil crusts can emit nitrous acid (HONO) and nitric oxide (NO). The terrestrial ground surface in arid and semiarid regions is anticipated to play an important role in the local atmospheric HONO budget, deemed to represent one of the unaccounted-for HONO sources frequently observed in field studies. In this study HONO and NO emissions from a representative variety of soil and biological soil crust samples from the Mediterranean island Cyprus were investigated under controlled laboratory conditions. A wide range of fluxes was observed, ranging from 0.6 to 264 ng m −2 s −1 HONO-N at optimal soil water content (20–30 % of water holding capacity, WHC). Maximum NO-N fluxes at this WHC were lower (0.8–121 ng m −2 s −1) . The highest emissions of both reactive nitrogen species were found from bare soil, followed by light and dark cyanobacteria-dominated biological soil crusts (biocrusts), correlating well with the sample nutrient levels (nitrite and nitrate). Extrapolations of lab-based HONO emission studies agree well with the unaccounted-for HONO source derived previously for the extensive CYPHEX field campaign, i.e., emissions from soil and biocrusts may essentially close the Cyprus HONO budget.