2631. |
2632. Sarival Sosič: Vsaka slika je zgodbaSarival Sosič, 2020, predgovor, uvodnik, spremna beseda Opis: Akademski slikar Bojan Bensa tokrat predstavlja izbor slikarskih del vse od leta 1983 dalje pa do svojih zadnjih slik, ki so nastale v obdobju 2019 in tudi v začetku leta 2020. Razstava s poetičnim naslovom Pomembne zgodbe močno žarijo že v samem naslovu opredeli tisto najbolj izrazito polje Bensinega ustvarjanja kot so močne, živahne, tudi divje barve. In prav skozi sicer domišljeno, a tudi občasno impulzivno nebrzdano barvno silovitostjo, pred nami nastaja svet podob, svet prežet s figuraliko tako ljudi kot živali in predvsem likovni svet, ki niha med konkretnostjo oziroma naslonom na določene vsebine in med meditativnostjo z rahlo navezavo ali na magičnost ali celo na nadrealnost upodobljenega. Bensa v slike pogosto umešča neobičajna razmerja med človekom in živaljo, jih slikarsko preučuje, razvija in zelo intuitivno razširja v bolj celovit in konotativno bogat pripovedni sistem. V slikah se prepletajo številni podtoni, pojavljajo variabilna in razrahljana mesta, kjer se pomeni vedno znova izmikajo v področja naključnega, nedefiniranega, nepojasnjenega, slutečega in zelo skrivnostnega. Prikazane pozicije in približani odnosi človeka in živali ne izpostavljajo nobenega hierarhičnega razmerja, kjer bi figure človeka prevladovale, pač pa se med živalmi in ljudmi vzpostavlja enakovreden, privlačen, celo atraktiven in pristen odnos. Slikar razkriva primarnost, naravnost, nekakšno arhaičnost odnosov bitij, ki so se v razvoju verjetno zaradi človeka preveč oddaljili in se medsebojno pogostokrat izključevali. Bensa uresničuje podobe večinoma na kontemplativnih barvnih odnosih, saj tako pospešuje kontraste ter ustvarja potrebno dramatičnost likovne zgodbe ter določeno mero skrivnostnosti, ki mu je še posebej blizu. Predvsem daljni, neobičajno privlačni in tudi občasno težje razumljeni ter skrivnostni svet Azije, predvsem Japonske kulture, jo že od slikarjevega ustvarjalnega začetka dalje bistveni likovni sistem, ki tako vsebinsko kot tudi barvno gradi številne likovne serije.
In kakšna je nekoliko podrobneje analizirana Bensina likovna govorica? Umetnik sistematično preučuje razmerja med figurami umeščenimi v prostore, ki se na asociativni plasti povezujejo z znanimi okolji, hkrati pa je figuralni svet ujet v ali izmuzljivo ali pa točno določeno idejo, ki jo Bensa naprej spoznava in nato preučuje ter postopno razvija in povezuje z različnimi stopnjami bivanja in raznolikimi doživljaji iz osebnega življenja. Tako ustvarja vzporednosti med zgodbeno realnostjo in med zgodbeno mističnostjo, pri čemer vedno ostaja na ravninah prepoznavnosti in določene logičnosti, ki sliko zapakirajo v vabljivo barvno, vsebinsko likovno energijo, ki žari s sten in zaobjame gledalca ter ga popelje v svet likovne kontemplacije. Likovno polje umetnika se razvija skozi stopnjevano barvno učinkovanje, odkrivanje novih razmerij med barvno gostoto, likovno strukturo in dinamizmom oblik v prostoru. Tako so barvni nanosi narejeni ali v hitrih, sunkovitih gestah, z ekspresivnim značajem ali pa so premišljeni, umirjeni postopki nanašanja, prepletanja barv znotraj različnih vertikalnih in horizontalnih polj, tudi ostreje lomljenih linij, ki na takšen način izpostavijo poudarjeno ekspresivnost. Tako so barvne napetosti obravnavane tudi kot živahne raznolikosti svetlobno-barvnega plastenja.
Ključne besede: slikarsko plastenje, slika je zgodba, barvna uglašenost, močne barve v slikah, razmerje med figuro in prostorom, telo kot prizorišče osebnih in družbenih prepletanj
Objavljeno v RUNG: 20.07.2020; Ogledov: 2908; Prenosov: 0 |
2633. |
2634. Chemical characterization of PM2.5 and source apportionment of organic aerosol in New Delhi, IndiaAnna Tobler, Deepika Bhattu, Francesco Canonaco, Vipul Lalchandani, Ashutosh Shukla, Navaneeth Thamban, Suneeti Mishra, Atul Srivastava, Deewan Bisht, Suresh Tiwari, Surender Singh, Griša Močnik, Urs Baltensperger, Sachchida Tripathi, J. G. Slowik, André S. H. Prévôt, 2020, izvirni znanstveni članek Opis: Delhi is one of the most polluted cities worldwide and a comprehensive understanding and deeper insight into the air pollution and its sources is of high importance. We report 5 months of highly time-resolved measurements of non-refractory PM2.5 and black carbon (BC). Additionally, source apportionment based on positive matrix factorization (PMF) of the organic aerosol (OA) fraction is presented. The highest pollution levels are observed during winter in December/January. During that time, also uniquely high chloride concentrations are measured, which are sometimes even the most dominant NR-species in the morning hours. With increasing temperature, the total PM2.5 concentration decreases steadily, whereas the chloride concentrations decrease sharply. The concentrations measured in May are roughly 6 times lower than in December/January. PMF analysis resolves two primary factors, namely hydrocarbon-like (traffic-related) OA (HOA) and solid fuel combustion OA (SFC-OA), and one or two secondary factors depending on the season. The uncertainties of the PMF analysis are assessed by combining the random a-value approach and the bootstrap resampling technique of the PMF input. The uncertainties for the resolved factors range from ±18% to ±19% for HOA, ±7% to ±19% for SFC-OA and ±6 % to ±11% for the OOAs. The average correlation of HOA with eBCtr is R2 = 0.40, while SFC-OA has a correlation of R2 = 0.78 with eBCsf. Anthracene (m/z 178) and pyrene (m/z 202) (PAHs) are mostly explained by SFC-OA and follow its diurnal trend (R2 = 0.98 and R2 = 0.97). The secondary oxygenated aerosols are dominant during daytime. The average contribution during the afternoon hours (1 pm–5 pm) is 59% to the total OA mass, with contributions up to 96% in May. In contrast, the primary sources are more important during nighttime: the mean nightly contribution (22 pm–3 am) to the total OA mass is 48%, with contributions up to 88% during some episodes in April.
Ključne besede: New Delhi, PM2.5, Source apportionment, PMF
Objavljeno v RUNG: 20.07.2020; Ogledov: 2552; Prenosov: 0
Gradivo ima več datotek! Več... |
2635. Water reveals non-Arrhenius kinetics in protein folding experimentsArtem Badasyan, 2020, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Opis: Statistical theories describe systems in equilibrium, and cannot be used to study kinetics. However, the theo-
ries are based on coarse-grained parameters, that include assumptions regarding the underlying kinetics. If
such assumptions are incorrect, the theoretical expressions, used to process the experimental data, will not
fit. I report on one such case we have met within the application of Zimm-Bragg [1] theory to process folding
experiments, and discuss the reasons and consequences.
Studies of relaxation phenomena in glass-forming liquids by default account for the shift in temperature by
some value, corresponding to the glass formation temperature, .In particular, temperature
shift
appears in hydrated proteins because of the presence of partially glassy states giving rise to
non-
Arrhenius relaxation times log τ ~ [2].
A phenomenological approach was suggested
by Adam and Gibbs as early as in 1965 to describe
the sudden increase of viscosity and the slowing down of the collective modes in super-cooled liquids as the
temperature is approaching[3]. The key idea of Adam-Gibbs theory was to consider the supercooled liquid
as a set of clusters (cooperatively rearranging regions) of different sizes that change with temperature,
giving rise to the shift in re-
laxation time. The temperature shift factor is present in many theories
describing properties of water.
Thus, Truskett and Dill had to include the Adamm-Gibbs temperature
shift into their simple analytical model of water to achieve the agreement with experimental data on the tem-
perature dependence of self-diffusion coefficient [4]. Later, Schiro and Weik have summarised recent in vitro
and in silico experimental results regarding the role of hydration water in the onset of protein structural dy-
namics, and have reported the presence of super-Arrhenius relaxation region above the ”protein dynamic
transition” temperature [4]. Recently, Mallamace et al have used the Adam-Gibbs theory in their NMR meas-
urements of protein folding-unfolding in water [4] and to rationalise the complicated pressure-temperature
diagrams in these glass-forming systems.
Motivated by the considerations above, and taking into account the
relationship between the
unimolecular rate of folding in water and the relaxation time 45 , we
introduce the
tem-
perature shift into the formulas used to fit experimental data on hydrated polypeptides.
By doing so we resolve the paradox and complete the new method of processing the Circular Dichroism ex-
perimental data on protein folding
Ključne besede: water, protein folding, non-Arrhenius kinetics
Objavljeno v RUNG: 20.07.2020; Ogledov: 2670; Prenosov: 112
 Celotno besedilo (2,35 MB) |
2636. Electromagnetic emission of white dwarf binary mergersJorge Armando Rueda, Remo Ruffini, Yu Wang, Carlo Luciano Bianco, J.M. Blanco-Iglesias, Mile Karlica, P. Lorén-Aguilar, Rahim Moradi, Narek Sahakyan, 2019, izvirni znanstveni članek Opis: It has been recently proposed that the ejected matter from white dwarf (WD) binary mergers can produce transient, optical and infrared emission similar to the "kilonovae" of neutron star (NS) binary mergers. To confirm this we calculate the electromagnetic emission from WD-WD mergers and compare with kilonova observations. We simulate WD-WD mergers leading to a massive, fast rotating, highly magnetized WD with an adapted version of the smoothed-particle-hydrodynamics (SPH) code Phantom. We thus obtain initial conditions for the ejecta such as escape velocity, mass and initial position and distribution. The subsequent thermal and dynamical evolution of the ejecta is obtained by integrating the energy-conservation equation accounting for expansion cooling and a heating source given by the fallback accretion onto the newly-formed WD and its magneto-dipole radiation. We show that magnetospheric processes in the merger can lead to a prompt, short gamma-ray emission of up to ≈ 1046 erg in a timescale of 0.1-1 s. The bulk of the ejecta initially expands non-relativistically with velocity 0.01 c and then it accelerates to 0.1 c due to the injection of fallback accretion energy. The ejecta become transparent at optical wavelengths around ~ 7 days post-merger with a luminosity 1041-1042 erg s-1. The X-ray emission from the fallback accretion becomes visible around ~ 150-200 day post-merger with a luminosity of 1039 erg s-1. We also predict the post-merger time at which the central WD should appear as a pulsar depending on the value of the magnetic field and rotation period.
Ključne besede: Astrophysics - High Energy Astrophysical Phenomena
Objavljeno v RUNG: 20.07.2020; Ogledov: 2633; Prenosov: 0
Gradivo ima več datotek! Več... |
2637. On the GeV Emission of the Type I BdHN GRB 130427ARemo Ruffini, Rahim Moradi, Jorge Armando Rueda, Carlo Luciano Bianco, Christian Cherubini, Simonetta Filippi, Yen-Chen Chen, Mile Karlica, Narek Sahakyan, Yu Wang, She Sheng Xue, Laura Beccera, 2019, izvirni znanstveni članek Opis: We propose that the inner engine of a type I binary-driven hypernova (BdHN) is composed of Kerr black hole (BH) in a non-stationary state, embedded in a uniform magnetic field B_0 aligned with the BH rotation axis and surrounded by an ionized plasma of extremely low density of 10^−14 g cm−3. Using GRB 130427A as a prototype, we show that this inner engine acts in a sequence of elementary impulses. Electrons accelerate to ultrarelativistic energy near the BH horizon, propagating along the polar axis, θ = 0, where they can reach energies of ~10^18 eV, partially contributing to ultrahigh-energy cosmic rays. When propagating with $\theta \ne 0$ through the magnetic field B_0, they produce GeV and TeV radiation through synchroton emission. The mass of BH, M = 2.31M ⊙, its spin, α = 0.47, and the value of magnetic field B_0 = 3.48 × 10^10 G, are determined self consistently to fulfill the energetic and the transparency requirement. The repetition time of each elementary impulse of energy ${ \mathcal E }\sim {10}^{37}$ erg is ~10^−14 s at the beginning of the process, then slowly increases with time evolution. In principle, this "inner engine" can operate in a gamma-ray burst (GRB) for thousands of years. By scaling the BH mass and the magnetic field, the same inner engine can describe active galactic nuclei.
Ključne besede: black hole physics, binaries, gamma-ray burst, neutron stars, supernovae, Astrophysics - High Energy Astrophysical Phenomena
Objavljeno v RUNG: 20.07.2020; Ogledov: 2843; Prenosov: 0
Gradivo ima več datotek! Več... |
2638. Magnetic Fields and Afterglows of BdHNe: Inferences from GRB 130427A, GRB 160509A, GRB 160625B, GRB 180728A, and GRB 190114CJorge Armando Rueda, Remo Ruffini, Mile Karlica, Rahim Moradi, Yu Wang, 2020, izvirni znanstveni članek Opis: GRB 190114C is the first binary-driven hypernova (BdHN) fully observed from initial supernova (SN) appearance to the final emergence of the optical SN signal. It offers an unprecedented testing ground for the BdHN theory, which is here determined and further extended to additional gamma-ray bursts (GRBs). BdHNe comprise two subclasses of long GRBs, with progenitors a binary system composed of a carbon–oxygen star (COcore) and a neutron star (NS) companion. The COcore explodes as an SN, leaving at its center a newborn NS (νNS). The SN ejecta hypercritically accretes on both the νNS and the NS companion. BdHNe I are very tight binaries, where the accretion leads the companion NS to gravitationally collapse into a black hole (BH). In BdHN II, the accretion rate onto the NS is lower, so there is no BH formation. We observe the same afterglow structure for GRB 190114C and other selected examples of BdHNe I (GRB 130427A, GRB 160509A, GRB 160625B) and for BdHN II (GRB 180728A). In all cases, the afterglows are explained via the synchrotron emission powered by the νNS, and their magnetic field structures and their spin are determined. For BdHNe I, we discuss the properties of the magnetic field embedding the newborn BH, which was inherited from the collapsed NS and amplified during the gravitational collapse process, and surrounded by the SN ejecta.
Ključne besede: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology
Objavljeno v RUNG: 20.07.2020; Ogledov: 2606; Prenosov: 0
Gradivo ima več datotek! Več... |
2639. A new optical-based technique for real-time measurements of mineral dust concentration in PM10 using a virtual impactorLuka Drinovec, Jean Sciare, IASONAS STAVROULAS, Spiros Bezantakos, Michael Pikridas, FLORIN UNGA, Chrysanthos Savvides, Bojana Višnjić, Maja Remškar, Griša Močnik, 2020, izvirni znanstveni članek Opis: Atmospheric mineral dust influences Earth’s radiative
budget, cloud formation, and lifetime; has adverse
health effects; and affects air quality through the increase of
regulatory PM10 concentrations, making its real-time quantification
in the atmosphere of strategic importance. Only
few near-real-time techniques can discriminate dust aerosol
in PM10 samples and they are based on the dust chemical
composition. The online determination of mineral dust using
aerosol absorption photometers offers an interesting and
competitive alternative but remains a difficult task to achieve.
This is particularly challenging when dust is mixed with
black carbon, which features a much higher mass absorption
cross section. We build on previous work using filter photometers
and present here for the first time a highly timeresolved
online technique for quantification of mineral dust
concentration by coupling a high-flow virtual impactor (VI)
sampler that concentrates coarse particles with an aerosol absorption
photometer (Aethalometer, model AE33). The absorption
of concentrated dust particles is obtained by subtracting
the absorption of the submicron (PM1) aerosol fraction
from the absorption of the virtual impactor sample (VIPM1
method). This real-time method for detecting desert
dust was tested in the field for a period of 2 months (April and
May 2016) at a regional background site of Cyprus, in the
Eastern Mediterranean. Several intense desert mineral dust
events were observed during the field campaign with dust
concentration in PM10 up to 45 μgm
Ključne besede: aerosol absorption, mineral dust, on-line detection, air quality
Objavljeno v RUNG: 20.07.2020; Ogledov: 2751; Prenosov: 0
Gradivo ima več datotek! Več... |
2640. Substantial brown carbon emissions from wintertime residential wood burning over FranceYunjiang Zhang, Alexandre Albinet, Jean-Eudes Petit, Véronique Jacob, Florie Chevrier, Gregory Gille, Sabrina Pontet, Eve Chrétien, Marta Dominik-Sègue, Gilles Levigoureux, Griša Močnik, Valérie Gros, Jean-Luc Jaffrezo, Olivier Favez, 2020, izvirni znanstveni članek Opis: Brown carbon (BrC) is known to absorb light at subvisible wavelengths but its optical properties and sources are still poorly documented, leading to large uncertainties in climate studies. Here, we show its major wintertime contribution to total aerosol absorption at 370 nm (18–42%) at 9 different French sites. Moreover, an excellent correlation with levoglucosan (r2 = 0.9 and slope = 22.2 at 370 nm), suggesting important contribution of wood burning emissions to ambient BrC aerosols in France. At all sites, BrC peaks were mainly observed during late evening, linking to local intense residential wood burning during this time period. Furthermore, the geographic origin analysis also highlighted the high potential contribution of local and/or small-regional emissions to BrC. Focusing on the Paris region, twice higher BrC mass absorption efficiency value was obtained for less oxidized biomass burning organic aerosols (BBOA) compared to more oxidized BBOA (e.g., about 4.9 ± 0.2 vs. 2.0 ± 0.1 m2 g−1, respectively, at 370 nm). Finally, the BBOA direct radiative effect was found to be 40% higher when these two BBOA fractions are treated as light-absorbing species, compared to the non-absorbing BBOA scenario.
Ključne besede: Brown carbon, Multi sites, Residential wood burning, Mass absorption efficiency, France
Objavljeno v RUNG: 20.07.2020; Ogledov: 3042; Prenosov: 0
Gradivo ima več datotek! Več... |
