Search results for "peni"

Phosphasalen group IV metal complexes: synthesis, characterization and ring opening polymerization of lactide.

2020

International audience; We report the synthesis of a series of Zr and Ti complexes bearing phosphasalen which differs from salen by the incorporation of two P atoms in the ligand backbone. The reaction of phosphasalen proligands (1a-1c)H2 with Zr(CH2Ph)4 led to different products depending on the nature of the N,N-linker in the ligand. In case of ethylene-linked phosphasalen, octahedral Zr complex 2a formed as a single stereoisomer in trans geometry. With the phenylene linker, it was shown by dynamic NMR spectroscopy that complex 2b exists as a mixture of trans and cis-β isomers in solution, both enantiomers (Δ and Λ) of the cis-β isomer being in fast equilibrium with respect to the NMR tim…

Ring opening polymerization of d,l-lactide and ε-caprolactone catalysed by (pyrazol-1-yl)copper(ii) carboxylate complexes

2021

1,2-Bis{(3,5-dimethylpyrazol-1-yl)methyl}benzene (L) reacts with [Cu(OAc)2] and C6H5COOH, 4-OH-C6H4COOH, 2-Cl-C6H4COOH and (3,5-NO2)2-C6H3COOH to afford the copper complexes [Cu2(C6H5COO)4(L)2] (1), [Cu2(4-OH-C6H4COO)4(L)2] (2), [Cu2(2-Cl-C6H4COO)4(L)2]n (3) and [Cu{(3,5-NO2)2-C6H3COO}2L]n (4) which are characterised by IR, mass spectrometry, elemental analyses, and X-ray crystallography. The structural data revealed two geometries that are adopted by the complexes: (i) paddle wheel in 1, 2·7H2O, 3 and (ii) regular chains in 3 and 4. Magnetic studies show strong antiferromagnetic couplings in the paddle wheel complexes and a weak antiferromagnetic coupling in the monometallic chain one. Cat…

The complementary structural studies of the double metal cyanide type catalysts for the ring opening polymerization of the oxiranes

2016

Thematic vent opening probability maps and hazard assessment of small-scale pyroclastic density currents in the San Salvador volcanic complex (El Sal…

2021

The San Salvador volcanic complex (El Salvador) and Nejapa-Chiltepe volcanic complex (Nicaragua) have been characterized by a significant variability in eruption style and vent location. Densely inhabited cities are built on them and their surroundings, including the metropolitan areas of San Salvador (∼2.4 million people) and Managua (∼1.4 million people), respectively. In this study we present novel vent opening probability maps for these volcanic complexes, which are based on a multi-model approach that relies on kernel density estimators. In particular, we present thematic vent opening maps, i.e., we consider different hazardous phenomena separately, including lava emission, small-scale…

Biological and microclimatic monitoring for conservation of cultural heritage: a case study at the De Rossi room of the Palatina library in Parma

2019

Biological particles in heritage-related indoor environments (museums, libraries, archives) represent a hazard to artifacts (biodeteriogenic action), operators and visitors’ health. The aim of the study was to evaluate environmental biological contamination and microclimate conditions in different periods of the year in De Rossi room of the historical Palatina Library in Parma. Microclimatic measurements were recorded continuously for a period ranging from 11 to 17 days in: January–February, May and September 2017. Monitoring of bacterial and fungal contamination was performed for air by active and passive sampling and by nitrocellulose membranes on shelves and manuscripts. Microorganisms w…

L’ évolution des assemblages lithiques des niveaux du Paléolithique moyen de l’Abrigo de la Quebrada (Valencia, Espagne)

2018

L’Abrigo de la Quebrada propose une séquence stratigraphique importante, avec neuf niveaux dont sept présentent des preuves d’occupation appartenant au Paléolithique moyen. De plus, l’existence d’un niveau stérile, le VI, séparant les niveaux supérieurs (II à V) des niveaux inférieurs (VII à IX), permet d’évaluer, dans une perspective diachronique, les changements constatés sur les différentes matiàres premières et sur les systémes de débitage employés pour chacune de ces deux grandes phases. Ces donne´ es sont compare´ es a` d’autres sites contemporains, dans le but d’e´valuer les normes technologiques et la gestion des ressources des ne´ andertaliens dans la zone ge´ographique de la re´gi…

A 1286‐year hydro‐climate reconstruction for the Balkan Peninsula

2018

We present a June-July drought reconstruction based on the standardized precipitation index (SPI) for the Balkan Peninsula over the period 730-2015 CE. The reconstruction is developed using a compo ...

Sello alimentario romano relacionado con Juno Sospita procedente del SE Hispano

2017

Roman alimentary stamps have an iconography that sometimes is difficult to interpret. In this paper, some valuations on the images displayed on both sides of one of these objects, namely an example belonging to a private collection in Murcia, are offered. In its original publication a relation to agrarian cults through motifs that would refer to the goddess Ceres was proposed. However, it is a composition having its closest parallels in a series of Roman Republican coins issued in 64 bc by Lucio Roscio Fabato. These denarii are mainly linked to Juno Sospita and secondarily also to the Egyptian cults of Mediterranean expansion. Therefore we evaluate the possibility that such religious intera…

Dead wood gathering among Neanderthal groups: Charcoal evidence from Abric del Pastor and El Salt (Eastern Iberia)

2017

International audience; We present here a new approach combining the microscopic characterization of fungal decay features and the fragmentation degree of the charcoal remains from Middle Palaeolithic combustion structures: features H4 and H11 from Abric del Pastor, unit IV (>75 ka BP) and features H50 and H57 from El Salt, unit Xb (ca. 52 ka BP), Eastern Iberia. The observation of wood degradation patterns that occurred prior to charring followed by their quantitative analysis according to previous experimental studies revealed differences between the alteration degrees of the firewood used in the hearths, highlighting the existence of firewood acquisition criteria based on dead wood gathe…

Revisiting the Epipalaeolithic-Neolithic Transition in the Extreme NW of Africa : The Latest Results of the Chronological Sequence of the Cave of Kaf…

2021

[EN] This study focuses on the chronostratigraphic sequence of the Cave of Kaf Taht el-Ghar (Dar Ben Karrich, Tétouan, Morocco) excavated in 2012 in the framework of the AGRIWESTMED research project. The broad sequence reveals a series of occupations ranging from the Pleistocene (Moroccan Aterian) to recent historical times. Our research identifies a rich Early Neolithic phase (sixth millennium cal BC) containing the earliest pottery and domesticated animal and plant remains in the western Maghreb. However, this Early Neolithic level is not an immediate successor of the last traces of the Epipalaeolithic hunter-gatherer occupation, which started at the end of the Younger Dryas (10,900–9700 …