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Ključne besede: cosmology, strong lensing, supernovae
Objavljeno v RUNG: 07.09.2023; Ogledov: 2531; Prenosov: 5
Celotno besedilo (18,56 MB)

Opis: Predicting variations in dissolved oxygen concentration (DO) is important for management and environmental monitoring of aquatic ecosystems. Regression analyses and univariate and multivariate time-series analyses based on autoregressive methods were performed to investigate oxygen conditions in the Pivka River, Slovenia. The monitoring site was established upstream where the river sinks into the karst cave Postojnska jama, which hosts one of the richest subterranean faunas yet studied worldwide. It was found that abnormal variations of DO started to be noticeable at values of DO < 3 mg/L and became more pronounced until the ecosystem reached fully anoxic conditions. The abnormal fluctuations during the critical summer period were due to environmental conditions, organic load and resident biota. Predictions for future detection of anomalies in DO values were made from stable residuals of the measured data, and it was demonstrated that the model could be used to obtain a reliable estimate for a short period, such as one day. The example presented an analysis pipeline based on specific and established threshold DO values, and it is particularly important for ecosystems with diversity hotspots where prolonged low DO values can pose a threat to their biota.
Ključne besede: karst (geology), aquatic ecosystems, dissolved oxygen, modelling, prediction
Objavljeno v RUNG: 05.09.2023; Ogledov: 3034; Prenosov: 8
Celotno besedilo (15,17 MB)
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Opis: Electrochemical chlorine evolution reaction is of central importance in the chlor-alkali industry, but the chlorine evolution anode is largely limited by water oxidation side reaction and corrosion-induced performance decay in strong acids. Here we present an amorphous CoOxCly catalyst that has been deposited in situ in an acidic saline electrolyte containing Co2+ and Cl- ions to adapt to the given electrochemical condition and exhibits ~100% chlorine evolution selectivity with an overpotential of ~0.1 V at 10 mA cm−2 and high stability over 500 h. In situ spectroscopic studies and theoretical calculations reveal that the electrochemical introduction of Cl- prevents the Co sites from charging to a higher oxidation state thus suppressing the O-O bond formation for oxygen evolution. Consequently, the chlorine evolution selectivity has been enhanced on the Cl-constrained Co-O* sites via the Volmer-Heyrovsky pathway. This study provides fundamental insights into how the reactant Cl-itself can work as a promoter toward enhancing chlorine evolution in acidic brine.
Ključne besede: catalyst synthesis, electrocatalysis, chlorine evolution
Objavljeno v RUNG: 04.09.2023; Ogledov: 4231; Prenosov: 8
Celotno besedilo (3,05 MB)
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Opis: The presence of several distinct minima in nearest-neighbor potentials in polymers makes it possible to describe polymer conformations in terms of discrete isomeric states, naturally leading to spin language. Using this general approach, a decade ago we have suggested the Hamiltonian formulation for the Zimm and Bragg model of protein conformations [1,2]. Later we have augmented the model by an oversimplified spin model for water, resulting in both cold and hot denaturations [3]. We construct the Statistical Mechanics for the model and get access to its Thermodynamics. Resulting order parameter and specific heat expressions are successfully fit to available experimental data [4]. Thanks to solid and traceable theoretical foundations, the procedure provides better quality fits as compared to the state-of-the-art two-state model, routinely used to process protein folding experiments.
Ključne besede: spin model, water, protein folding
Objavljeno v RUNG: 04.09.2023; Ogledov: 3129; Prenosov: 7
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Opis: Tina je 26. avgusta 2011 polna pričakovanj pristala v Združenih arabskih emiratih in ti so postali njen dom za skoraj desetletje. Na potopisnem predavanju bo spregovorila o tem, kako se je v pretežno muslimanski državi počutila kot študentka naravoslovja, kako ZAE spodbujajo razvoj kulturnih dejavnosti in zakaj je kar 80 % prebivalcev tujcev. In o znamenitostih: steklenih stolpnicah in blišču Dubaja, neskončnih puščavah Abu Dabija, konjih in kamelah za lepotna tekmovanja v Adžmanu, skalnih gorovjih v Ras Al Khaimah in Umm Al Quwainu ter lepotah Indijskega oceana v Fudžeiri.
Ključne besede: Abu Dabi, Dubaj, Sharjah, Fujairah, Ras al Khaimah, Umm al Quwain, Ajman
Objavljeno v RUNG: 01.09.2023; Ogledov: 1997; Prenosov: 6
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