Search results for "LOI"
showing 10 items of 4617 documents
Insights into the Mechanism of Anodic N–N Bond Formation by Dehydrogenative Coupling
2017
The electrochemical synthesis of pyrazolidine-3,5-diones and benzoxazoles by N-N bond formation and C,O linkage, respectively, represents an easy access to medicinally relevant structures. Electrochemistry as a key technology ensures a safe and sustainable approach. We gained insights in the mechanism of these reactions by combining cyclovoltammetric and synthetic studies. The electron-transfer behavior of anilides and dianilides was studied and led to the following conclusion: The N-N bond formation involves a diradical as intermediate, whereas the benzoxazole formation is based on a cationic mechanism. Besides these studies, we developed a synthetic route to mixed dianilides as starting m…
Highly Anisotropic Rhenium(IV) Complexes: New Examples of Mononuclear Single-Molecule Magnets
2013
The rhenium(IV) complex (NBu4)2[ReBr4(ox)] (1) (ox = oxalate and NBu4(+) = tetra-n-butylammonium cation) has been prepared and its crystal structure determined by X-ray diffraction. The structure is made up of discrete [ReBr4(ox)](2-) anions and bulky NBu4(+) cations. Each [ReBr4(ox)](2-) anion is surrounded by six NBu4(+) cations, which preclude any significant intermolecular contact between the anionic entities, the shortest rhenium···rhenium distance being 9.373(1) Å. Variable temperature dc and ac magnetic susceptibility measurements and field-dependent magnetization experiments on polycrystalline samples of 1 reveal the occurrence of highly anisotropic magnetically isolated Re(IV) cent…
Unexpected Scholl Reaction of 6,7,13,14-Tetraarylbenzo[k]tetraphene: Selective Formation of Five-Membered Rings in Polycyclic Aromatic Hydrocarbons
2016
Cyclodehydrogenation is a versatile reaction that has enabled the syntheses of numerous polycyclic aromatic hydrocarbons (PAHs). We now describe a unique Scholl reaction of 6,7,13,14-tetraarylbenzo[k]tetraphene, which "unexpectedly" forms five-membered rings accompanying highly selective 1,2-shift of aryl groups. The geometric and optoelectronic nature of the resulting bistetracene analogue with five-membered rings is comprehensively investigated by single-crystal X-ray, NMR, UV-vis absorption, and cyclic voltammetry analyses. Furthermore, a possible mechanism is proposed to account for the selective five-membered-ring formation with the rearrangement of the aryl groups, which can be ration…
THEMIS: A Parameter Estimation Framework for the Event Horizon Telescope
2020
This is an open access article.-- Full list of authors: Broderick, Avery E.; Gold, Roman; Karami, Mansour; Preciado-López, Jorge A.; Tiede, Paul; Pu, Hung-Yi; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Baloković, Mislav; Barrett, John; Bintley, Dan; Blackburn, Lindy; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chael, Andrew; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Conway, John E.; Cordes, James M.; Crew, Geoffrey B.; Cu…
Transferring deep learning models for cloud detection between Landsat-8 and Proba-V
2020
Abstract Accurate cloud detection algorithms are mandatory to analyze the large streams of data coming from the different optical Earth observation satellites. Deep learning (DL) based cloud detection schemes provide very accurate cloud detection models. However, training these models for a given sensor requires large datasets of manually labeled samples, which are very costly or even impossible to create when the satellite has not been launched yet. In this work, we present an approach that exploits manually labeled datasets from one satellite to train deep learning models for cloud detection that can be applied (or transferred) to other satellites. We take into account the physical proper…
Planktic foraminiferal changes in the western Mediterranean Anthropocene
2021
The increase in anthropogenic induced warming over the last two centuries is impacting marine environment. Planktic foraminifera are a globally distributed calcifying marine zooplankton responding sensitively to changes in sea surface temperatures and interacting with the food web structure. Here, we study two high resolution multicore records from two western Mediterranean Sea regions (Alboran and Balearic basins), areas highly affected by both natural climate change and anthropogenic warming. Cores cover the time interval from the Medieval Climate Anomaly to present. Reconstructed sea surface temperatures are in good agreement with other results, tracing temperature changes through the Co…
Using mosses as biomonitors to study trace element emissions and their distribution in six different volcanic areas
2017
Volcanoes emit SO2, CO2, and H2S, but also trace elements gases and particles such as As, Cd, Cr, Cu, Hg, Ni, Pb, and Sb. Active moss bag biomonitoring, an easy to apply and low budget method, was used to determine trace element release from volcanic areas of different geological context and climates. Exposure height variations (0.7â1.6 m above ground) due to different availability of natural tie points did not affect the results. Accumulation was linear for exposure durations from three days to nine weeks, so values were comparable by normalization to moss exposure time. Uncovered moss bags showed higher accumulation than co-exposed covered ones because of additional dust and wet deposit…
Priedaine: A Neolithic Site at the Head of the Gulf of Riga
2016
The Neolithic site of Priedaine in Jūrmala was excavated on a small scale in 2007–2008, yielding an assemblage of Comb Ceramics, along with unique wooden implements and fragments of pine-lath fishing structures. The environment and subsistence resources are indicated by plant macrofossil remains and a small faunal collection. Located by a palaeolake and also very close to the sea, the site, dated to c. 3700–3500 cal BC, would have been oriented towards aquatic resource exploitation. However, it had a wider range of functions, as indicated by the evidence of flint and amber processing. Key words: Neolithic, pottery, fishing gear, plant macro-remains, faunal remains, lake, coastal settlement.…
Obsidian from the Site of Piano dei Cardoni, Ustica (Palermo, Italy): Preliminary Results on the First Occupation of the Island
2021
Abstract New investigations on Ustica (Palermo, Sicily) originated from the need to improve our knowledge of the island’s archaeological and environmental heritage. Through field surveys, particular attention was paid to human occupation in the Neolithic phases and focused on the less investigated southern side of the island. The systematic survey of the area of Piano dei Cardoni in 2018 brought to light a new Middle/Late Neolithic site, already partially documented in the literature. The island was settled for the first time during these phases, as also testified from the area of Punta Spalmatore. The presence of Serra d’Alto, incised dark burnished, and Diana styles suggests that the site…
Connecting Gien Castle to its Landscape: Faunal, Environmental and Buildings Analyses (Loiret, France)
2021
International audience; Gien castle is a listed monument of French architectural heritage. Today it houses the National Museum of Hunting and its collection. Organised visits to the site have traditionally lacked any clear mention of the castle’s historical background. Recently, however, archaeological excavations and building analysis in 2011–2015 produced a wealth of new knowledge about the castle’s medieval origins and history, and about its relationship to its landscape. During the ninth and tenth centuries and then in the fifteenth century the castle occupied a strategically exceptional position reflecting the connection with its environment, notably the strong connection between the c…