261 research outputs found
Domestic insurers in Poland and the global crisis
The article contains the analysis of the impact of global crisis on Polish insurance sector. The main areas of the crisis impact on the activity of Polish insurance companies has so far been the change in the assets value and the associated decline in the profitability of investment activity. The danger arising from the economic downturn has not been realized so far in the Polish insurance sector. Although the premium written is high, the structure of the portfolio in life insurances is changing. In 2008, however, a significant retreat from saving insurance policies with capital funds in the direction of structured products is observed. A significant increase in premiums written resulted in a good financial situation of Polish insurance companies. Despite the turmoil in financial markets it also seems that solvency of Polish insurance sector is unthreatened as measured by statutory ratios.insurance companies, Polish insurance market, global crisis
Sibilant harmony in Santiago Tzâutujil (Mayan)
We analyze sibilant harmony in the Santiago AtitlĂĄn dialect of Tzâutujil (Mayan), a phenomenon that was briefly described by Dayley (1985). Novel data show that the obligatory harmony process (i) is asymmetrical (triggered only by [+ant] sibilants), (ii) progressive, and (iii) applies long-distance. Furthermore, we argue that the process is not stem-controlled. In contextualizing the phenomenon within the typology of sibilant harmony (Hansson 2010), we conclude that it is unique. Finally, we suggest that Santiago Tzâutujil sibilant harmony has been stable diachronically because the target segment /Ê/ is always in the stressed syllable, thus being salient in the input during acquisition
Coordination without grammar-internal feature resolution
Morphological agreement with coordinate phrases involves a computation that takes as its input a set of features from each conjunct and outputs exactly one resolved set of features (number, person, grammatical gender/noun class, commonly labelled phi-features). Such resolution is typically taken to be grammar-internal because it relies on other grammar-internal ingredients (phi-features, agreement, coordination), and at least in some instances seems to follow systematic rules that may be captured by familiar grammatical operations. Exceptions to these apparent rules, if not ignored altogether, have received disparate analyses depending on the language, framework, and the particular features involved. In this thesis, I argue that it is such exceptions that are illuminating, and that the appearance of rigid rules is misleading. Treating variation in agreement with coordinate phrases as exceptional with respect to the otherwise deterministic output rules either delays the task of explaining the surface data, or risks weakening the language competence theory by adding the baroque stipulations that a purely grammar-internal treatment would require. Phi-agreement with coordinate phrases is subject to inter- and intra-speaker variability and ineffability; such variation is widespread in the worldâs languages, even the ones with limited phi-agreement morphology like English. I therefore reject the grammar-internal approach to agreement with coordinate phrases and argue instead that the agreement morphology we observe on the surface is due to grammar-external mechanisms being recruited to determine the resulting agreement morphology. Under this approach, systematicity in agreement with coordinations is only apparent and can be manipulated. The reason a grammar-internal mechanism is unavailable is because it would have to take place on the agreeing head (e.g., Infl0 or v0), and what we know about agreement between a syntactic head and multiple arguments (e.g., from omnivorous agreement and the Person Case Constraint) renders it ill-suited for the task of coordination resolution
Tetrathiafulvalene-Based Architectures: From Guests Recognition to Self-Assembly
The tetrathiafulvalene (TTF) unit has been successfully used for an incredibly broad range of applications. Beyond the well-established conducting properties of the corresponding cation-radical salts, this unit has appeared as a key redox-active component for various applications supported by its remarkable redox properties: a high Ï-donating ability and occurrence of three stable redox states. This article reviews the main contribution of the group of Angers to this field, highlighting results obtained in terms of redox-sensing as well as efforts carried out to reach new self-assembled TTF-based architectures
An electron-rich three dimensional receptor based on a calixarene-tetrathiafulvalene assembly
The synthesis of a calix[4]arene scaffold persubstituted with four redox-active tetrathiafulvalene (TTF) moieties at the lower rim is described. This assembly strongly binds sodium cation, and the binding process is accompanied by a conformational change of the receptor, as shown from NMR titration and by an X-ray diffraction led on the complex. This dynamic behavior remarkably results in a modification of the electrochemical response of TTF probes, which behave independently after sodium complexation
Teaching Strategies for Improving Algebra Knowledge in Middle and High School Students
This practice guide provides three recommendations for teaching algebra to students in middle school and high school. Each recommendation includes implementation steps and solutions for common roadblocks. The recommendations also summarize and rate supporting evidence. This guide is geared toward teachers, administrators, and other educators who want to improve their studentsâ algebra knowledge.https://lib.dr.iastate.edu/edu_books/1000/thumbnail.jp
Synthesis of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) derivatives functionalised with two, four or eight hydroxyl groups
Short synthetic routes to a range of BEDT-TTF derivatives functionalised with two, four or eight hydroxyl groups are reported, of interest because of their potential for introducing hydrogen bonding between donor and anion into their radical cation salts. The cycloaddition of 1,3-dithiole-2,4,5-trithione with alkenes to construct 5,6-dihydro-1,3-dithiolo[4,5-b]1,4-dithiin-2-thiones is a key step, with homo- or hetero-coupling procedures and O-deprotection completing the syntheses. The first synthesis of a single diastereomer of tetrakis(hydroxymethyl)BEDT-TTF, the cis, trans product, was achieved by careful choice of O-protecting groups to facilitate separation of homo- and hetero-coupled products. Cyclisation of the trithione with enantiopure 1R,2R,5R,6R-bis(O,O-isopropylidene)hex-3-ene-1,2,5,6-tetrol (from D-mannitol) gave two separable diastereomeric thiones, which can be transformed to enantiomeric BEDT-TTF derivatives with four or eight hydroxyl groups
Synergistic topological and supramolecular control of Diels-Alder reactivity based on a tunable self-complexing hos-guest molecular switch
International audienceCompartmentalization and bindingâtriggered conformational change regulate many metabolic processes in living matter. Here, we have synergistically combined these two biorelevant processes to tune the DielsâAlder (DA) reactivity of a synthetic selfâcomplexing hostâguest molecular switch CBPQT4+âFu, consisting of an electronârich furan unit covalently attached to the electronâdeficient cyclobis(paraquatâpâphenylene) tetrachloride (CBPQT4+, 4Clâ) host. This design allows CBPQT4+âFu to efficiently compartmentalize the furan ring inside its host cavity in water, thereby protecting it from the DA reaction with maleimide. Remarkably, the selfâcomplexed CBPQT4+âFu can undergo a conformational change through intramolecular decomplexation upon the addition of a stronger binding molecular naphthalene derivative as a competitive guest, triggering the DA reaction upon addition of a chemical regulator. Remarkably, connecting the guest onto a thermoresponsive lower critical solution temperature (LCST) copolymer regulator controls the DA reaction on command upon heating and cooling the reaction media beyond and below the cloud point temperature of the copolymer, representing a rare example of decreased reactivity upon increasing temperature. Altogether, this work opens up new avenues towards combined topological and supramolecular control over reactivity in synthetic constructs enabling control over reactivity through molecular regulators or even mild temperature variations
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