94 research outputs found
Mass absorption cross-section and absorption enhancement from long term black and elemental carbon measurements: A rural background station in Central Europe
Black carbon (BC) is a dominant aerosol light absorber, and its brown carbon (BrC) coating can enhance absorption and lead to uncertainties concerning the radiative forcing estimation. This study investigates the mass absorption cross-section of equivalent BC (MAC(eBC)) during a long-term field measurement (2013-2017) at a rural Central European site. The MAC enhancement factor (E-abs) and the contribution of BrC coatings to the absorption coefficient (B-abs) were estimated by combining different approaches. The annual mean B-abs and MAC(eBC) values decreased slightly over the measurement period associated with change in the submicron aerosol size distribution. Regardless of the wavelength, B-abs exhibited clear seasonal and diurnal variations, with higher values in winter when a higher absorption Angstromexponent (1.4) was observed due to the local biomass burning (BB). In contrast, MACeBC did not have a distinct temporal trend at 600 nm (7.84 +/- 2.79 m(2) g(-1)), while it showed a seasonal trend at 370 nm with higher values in winter (15.64 +/- 4.77 m(2) g(-1)). During this season, E-abs_(660) was 1.18 +/- 0.27 and did not exhibit any clear wavelength dependence, despite the influence of BB. During the study period, BrC-attributed absorption was observed in 31% of the samples, with a contribution of up to 40% of total Babs. In summer, the E-abs_(660) increased to 1.59 +/- 0.60, when a larger BC coating could be formed by secondary aerosol fractions. During this season, MAC(eBC)_ (660) and E-abs_(660) showed comparable source profiles that were mainly associated with aged air masses over central Europe, thereby supporting the fact that characteristics of coating materials formed during atmospheric aging are a major factor driving the MAC(eBC)_(660) measured at the regional background site. Further field investigations of the composition of BC coatings would help to better understand and estimate uncertainties related to the radiative effect of aerosols
Perzistentni, bioakumulativni i toksični spojevi u zemljama srednje i istočne Europe - najsuvremeniji izvještaj - izloženost ljudi
This review describes problems with persistent and bioaccumulative organic substances which posses toxic characteristics likely to cause adverse human health or environmental effects in countries of Central and Eastern Europe as far as human exposure is concerned. This paper is a part of a more detailed report on the subject.Ovaj pregledni rad dio je opsežna izvještaja koji opisuje probleme vezane uz perzistentne, bioakumulativne i toksične spojeve (PBT) u srednjoj i istočnoj Europi. Opisani su problemi izloženosti ljudi u zemljama srednje i istočne Europe perzistentnim i bioakumulativnim organskim spojevima koji imaju toksična svojstva, a koji mogu uzrokovati nepovoljne učinke na zdravlje ljudi
Perzistentni, bioakumulativni i toksični spojevi u zemljama srednje i istočne Europe - kritična mjesta
The sources and environmental levels of the PBTs in the countries of Central and Eastern Europe are broadly described. Most of the countries in the region produce and/or formulate pesticides. The pesticide registration is a primary requirement for import, production and distribution. The special attention must be given to unwanted pesticides. The problem of unwanted and expired pesticides pose the greatest danger to the natural environment and people which is brought about by the use of chemicals in agriculture in CEE countries. Countries still have not solve the problem of safety storage for PBTs and other chemicals classified as poisons and they have no special sites or facilities for destruction of these chemicals. This region has very specific problems of environmental pollution, which are the results of the recent wars. Destruction of industrial facilities and spilling of chemicals have the worst effect for the environment (Bosnia and Herzegovina, Croatia, Serbia and Montenegro).U radu su iscrpno opisani izvori i razine u okolišu perzistentnih bioakumulativnih i toksičnih spojeva (PBTs) u zemljama srednje i istočne Europe. U većini zemalja te regije proizvode se i/ili formuliraju pesticidi. Registracija pesticida osnovni je uvjet za uvoz, proizvodnju i distribuciju. Posebna pozornost mora se posvetiti nepoželjnim pesticidima. Nepoželjni pesticidi i oni kojima je istekao rok upotrebe najveća su opasnost za okoliš i ljude, uzrokovana primjenom kemijskih sredstava u poljoprivredi u zemljama srednje i istočne Europe. U većini zemalja još nije riješen problem sigurnosti skladištenja PBTs-a i ostalih kemikalija klasificiranih kao otrovi, a također nema posebnih mjesta ni ure|aja za uništavanje takvih kemikalija. Ova regija ima i specifičan problem onečišćenja okoliša kao posljedicu nedavnog rata. Razaranje industrijskih postrojenja i rasipanje kemikalija ima najgori učinak na okoliš (Bosna i Hercegovina, Hrvatska, Srbija i Makedonija)
Exploring the planetary boundary for chemical pollution
Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if “unacceptable global change” is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient evidence shows stresses on ecosystem and human health at local to global scales, suggesting that conditions are transgressing the safe operating space delimited by a PBCP. As such, current local to global pollution control measures are insufficient. However, while the PBCP is an important conceptual step forward, at this point single or multiple PBCPs are challenging to operationalize due to the extremely large number of commercial chemicals or mixtures of chemicals that cause myriad adverse effects to innumerable species and ecosystems, and the complex linkages between emissions, environmental concentrations, exposures and adverse effects. As well, the normative nature of a PBCP presents challenges of negotiating pollution limits amongst societal groups with differing viewpoints. Thus, a combination of approaches is recommended as follows: develop indicators of chemical pollution, for both control and response variables, that will aid in quantifying a PBCP(s) and gauging progress towards reducing chemical pollution; develop new technologies and technical and social approaches to mitigate global chemical pollution that emphasize a preventative approach; coordinate pollution control and sustainability efforts; and facilitate implementation of multiple (and potentially decentralized) control efforts involving scientists, civil society, government, non-governmental organizations and international bodies
On the Relationship Between the Optical Emission-Line and X-ray Luminosities in Seyfert 1 Galaxies
We have explored the relationship between the [O III] 5007 and the
2--10 keV luminosities for a sample of Broad- and Narrow-Line Seyfert 1
galaxies (BLSy1 and NLSy1, respectively). We find that both types of Seyferts
span the same range in luminosity and possess similar [O III]/X-ray ratios. The
NLSy1s are more luminous than BLSy1s, when normalized to their central black
hole masses, which is attributed to higher mass accretion rates. However, we
find no evidence for elevated [O III]/X-ray ratios in NLSy1s, which would have
been expected if they had excess EUV continuum emission compared to BLSy1s.
Also, other studies suggest that the gas in narrow-line regions (NLR) of NLSy1s
and NLSy1s span a similar range in ionization, contrary to what is expected if
those of the former are exposed to a stronger flux of EUV radiation. The
simplest interpretation is that, like BLSy1s, a large EUV bump is not present
in NLSy1s. However, we show that the [OIII]/X-ray ratio can be lowered as a
result of absorption of the ionizing continuum by gas close to the central
source, although there is no evidence that intrinsic line-of-sight absorption
is more common among NLSy1s, as would be expected if there were a larger amount
of circumnuclear gas. Other possible explanations include: 1) anisotropic
emission of the ionizing radiation, 2) higher gas densities in the NLR of
NLSy1s, resulting in lower average ionization, or 3) the presence of strong
winds in the the nuclei of NLSy1s which may drive off much of the gas in the
narrow-line region, resulting in lower cover fraction and weaker [O III]
emission.Comment: 18 pages, including 3 figures, 2 tables. Accepted for publication in
The Astrophysical Journa
Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease
Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.
Rozhovor Britských listů 584. Otrava řeky Bečvy: Problém, který se nevyšetřoval [Britské listy Interview 584. The poisoning of the Czech river Bečva: A problem that was not investigated]
The recent case of the poisoning of the Bečva River, in which tons of fish died, is symbolic evidence of the decay of the Czech state administration and the Czech judiciary. The authorities ruled out the guilt of the then Prime Minister Babiš's company Deza and arbitrarily imposed it on Energoaqua, which had nothing to do with the scandal. The case is now the subject of a lengthy legal process. In this Britské listy interview, Jan Čulík talks about the scandal with Professor Ivan Holoubek of the Research Centre for Toxic Compounds in the Environment. The interview was broadcast on the cable TV channel N8š region from Tuesday 28 March 2023
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