Results 21 to 30 of about 559,376 (319)

Palladium-Catalyzed Asymmetric Conjugate Addition of Arylboronic Acids to Five-, Six-, and Seven-Membered β-Substituted Cyclic Enones: Enantioselective Construction of All-Carbon Quaternary Stereocenters [PDF]

open access: yes, 2011
The first enantioselective Pd-catalyzed construction of all-carbon quaternary stereocenters via 1,4-addition of arylboronic acids to β-substituted cyclic enones is reported. Reaction of a wide range of arylboronic acids and cyclic enones using a catalyst
Gatti, Michele   +3 more
core   +2 more sources

On the identity of broad-shelled mussels (Mollusca, Bivalvia, Mytilus) from the Dutch delta region [PDF]

open access: yes, 2011
Late Quaternary (Eemian) deposits of the Netherlands contain shells that resemble those of living Mytilus galloprovincialis. Similar broad-shelled mytilids also occur in estuaries of the southwestern Netherlands together with slender individuals typical ...
Bos, M.M.   +9 more
core   +3 more sources

Additive Quaternary Codes Related to Exceptional Linear Quaternary Codes [PDF]

open access: yesIEEE Transactions on Information Theory, 2020
We study additive quaternary codes whose parameters are close to those of the extended cyclic [12; 6; 6]4-code or to the quaternary linear codes generated by the elliptic quadric in PG(3; 4) or its dual. In particular we characterize those codes in the category of additive codes and construct some additive codes whose parameters are better than those ...
Jurgen Bierbrauer   +2 more
openaire   +2 more sources

Morphology, biostratigraphy, and evolution of Pliocene-Pleistocene diatoms Proboscia barboi and Proboscia curvirostris

open access: yesGeologica Acta, 2019
Proboscia barboi and Proboscia curvirostris are two important diatom biostratigraphic markers from the high latitudes of the North Pacific and North Atlantic Oceans, dating back to the Pliocene-Pleistocene time.
J. Andrade   +3 more
doaj   +1 more source

THE ITALIAN QUATERNARY VOLCANISM

open access: yesAlpine and Mediterranean Quaternary, 2023
The peninsular and insular Italy are punctuated by Quaternary volcanoes and their rocks constitute an important aliquot of the Italian Quaternary sedimentary successions. Also away from volcanoes themselves, volcanic ash layers are a common and frequent feature of the Quaternary records, which provide us with potential relevant stratigraphic and ...
Stefano Branca1   +35 more
openaire   +5 more sources

Late Quaternary history of Lammefjorden, north-west Sjælland, Denmark

open access: yesGEUS Bulletin, 2020
Lammefjorden is a reclaimed fjord in north-west Sjælland, Denmark. Sediment cores from the area were collected to study its development after the last deglaciation, in particular the sea-level history.
Ole Bennike   +2 more
doaj   +1 more source

GEOMAGNETIC EXCURSION RECORD PRESERVED IN THE SPELEOTHEM FROM WESTERN CAUCASUS: FIRST DATA

open access: yesГеодинамика и тектонофизика, 2022
The study of the geomagnetic field evolution on minor timescales, in particular of such significant events as geomagnetic reversals and excursions, has acquired particular relevance nowadays due to the increased attention of mankind to the environment ...
D. A. Gavriushkin   +3 more
doaj   +1 more source

Polarization-Engineering in III-V Nitride Heterostructures: New Opportunities For Device Design [PDF]

open access: yes, 2010
The role of spontaneous and piezoelectric polarization in III-V nitride heterostructure devices is discussed. Problems as well as opportunities in incorporating polarization in abrupt and graded heterojunctions composed of binary, ternary, and quaternary
Albert   +14 more
core   +1 more source

Highly-crystallized quaternary chalcopyrite nanocrystals via a high-temperature dissolution–reprecipitation route [PDF]

open access: yes, 2011
Quaternary chalcopyrite (Cu2CoSnS4, Cu2ZnSnS4) nanocrystals displaying high crystallization and controlled morphology were synthesized via a high-temperature growth regime achieved by dissolution–reprecipitation of tailored ultrafine precursors in the ...
Balocchi, Andréa   +4 more
core   +2 more sources

Averages of Fourier coefficients of Siegel modular forms and representation of binary quadratic forms by quadratic forms in four variables

open access: yes, 2016
Let $-d$ be a a negative discriminant and let $T$ vary over a set of representatives of the integral equivalence classes of integral binary quadratic forms of discriminant $-d$.
A Earnest   +24 more
core   +1 more source

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