Even-odd alternation in mass spectrum of thymine and uracil clusters: Evidence of intracluster photodimerization

Multiphoton ionization of thymine and uracil clusters generated by a supersonic molecular beam gave rise to a remarkable alternation of mass spectral intensities between even- and odd-numbered clusters. Such alternation was observed in clusters of up to 30 molecules. Excitation to the two lowest electronically excited states seemed to be a strong prerequisite. In view of the well known photodimerization reaction of thymine and uracil in the bulk phase, it is proposed that such alternation in the mass spectral intensity resulted from formation of photodimer units within the cluster on intense UV irradiation. Several analogues of thymine with no known propensity for photodimerization in the bulk phase did not exhibit any sign of such alternation in the cluster mass spectrum. The intrinsic UV window for photodimerization, and hence photoinduced mammalian mutagenesis, was estimated to be approximately 210–280 nm, significantly narrower than the previously reported bulk values of 150–300 nm.

L'intercomprensione in Europa: una via per il plurilinguismo

Analisi del fenomeno dell'intercomprensione e dei suoi usi in ambito europeo. L'elaborato, strutturato in quattro parti, tratterà dell'Unione Europea e delle sue iniziative a sostegno del plurilinguismo, degli obiettivi dell'intercomprensione e dei suoi possibili usi, e infine dei progetti europei per favorire la diffusione di questo nuovo metodo didattico.

Sedimentology and paleontology on core Lz1104 from Lake Hjort, Greenland

Two sediment cores of 70 and 252 cm length were recovered from Hjort Sø, a small lake on Store Koldewey, Northeast Greenland, and studied with a multidisciplinary approach in order to reconstruct the local environmental history and to test the relevance of proxies for paleoenvironmental information. The basal sediments from the longer core are dominated by clastic matter, which was likely deposited during deglaciation of the lake basin. These clastic sediments are overlain by gyttja, which is also present throughout the shorter core. AMS radiocarbon dating was conducted on plant macrofossils of 11 samples from the gyttja in both cores. A reliable chronology was established for both cores, which dated the onset of organic accumulation at 9,500 cal. year BP. The Holocene temperature development, with an early to mid Holocene thermal maximum, is best reflected in the grain-size composition. Nutrient availability was apparently low during the early Holocene and led to low productivity in the lake and its vicinity. From ca. 7,000 cal. year BP, productivity in the lake increased significantly, probably induced by external nutrient input from goose excrements. From this time, micro- and macrofossil remains reflect relatively well the climate history of East Greenland, with a cooling during the middle Holocene, the medieval warming, and the Little Ice Age. The amount of organic matter in the sequence seems to be more affected by lake ice cover or by nutrient supply from the catchment than by temperature changes. The record from Hjort Sø thus reveals the difficulties in interpreting sedimentary records from high arctic regions.

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Philodicus, siue Dialogus de ptisana, eiusqu[ue] cremore non tantum pleuriticis, sed & morbis aliis exhibenda : in quo methodicè, ac per indicationes ad mentem Hippocratis, & Galeni omnia pertractantur; quaestionesq[ue] acutissimè, nouaq[ue] ratione disputantur, & resoluuntur ... /

Mode of access: Internet.

Historia ecclesiastica Veteris Testamenti in rem theologiae candidatorum, per sex mundi aetates ab orbe condito ad notale usque Jesu Christi ... : opus ex tribus tomis in unum volumen redactum /

Mode of access: Internet.

Bartholomaei de Moor veris oeconomiae animalis, seu potius humanae, principiis innixae pathologiae cerebri delineatio practica : in qua, morborum soporosorum, per notas characteristicas, distinctio nec non spasmorum accuratior distributio traditur.

Mode of access: Internet.

Sum[m]a diuersarum questionum medicinaliu[m] per ordine[m] alphabeti collectaru[m] Per magistru[m] Gabrielem de Taregua ... Aggregatio eiusde[m] de curis quaru[m]da[m] egritudinu[m] ... Textus Auicen[n]e per ordinem alphabeti in sente[n]tia per eundem reportatus ...

Mode of access: Internet.

D. Nicolai Bas et Galcerán ... Theatrum iurisprudentiae forensis valentinae, romanorum juri mirifice accommodatae; pars prima in duos tomos distributa; complectens perutiles, selectiores, practicabiliores que Forensis usus materias, [et] universam Praxim earum, quae, aut peraguntur in judicio summarie, aut per usum voluntariae jurisdictionis, cum formulis, [et] Libellis opportunis; tomus primus.

Mode of access: Internet.