Collaborative Broadcast in O(log log n) Rounds

We consider the multihop broadcasting problem for $n$ nodes placed uniformly at random in a disk and investigate the number of hops required to transmit a signal from the central node to all other nodes under three communication models: Unit-Disk-Graph (UDG), Signal-to-Noise-Ratio (SNR), and the wave superposition model of multiple input/multiple output (MIMO). In the MIMO model, informed nodes cooperate to produce a stronger superposed signal. We do not consider the problem of transmitting a full message nor do we consider interference. In each round, the informed senders try to deliver to other nodes the required signal strength such that the received signal can be distinguished from the noise. We assume sufficiently high node density $\rho= \Omega(\log n)$. In the unit-disk graph model, broadcasting needs $O(\sqrt{n/\rho})$ rounds. In the other models, we use an Expanding Disk Broadcasting Algorithm, where in a round only triggered nodes within a certain distance from the initiator node contribute to the broadcasting operation. This algorithm achieves a broadcast in only $O(\frac{\log n}{\log \rho})$ rounds in the SNR-model. Adapted to the MIMO model, it broadcasts within $O(\log \log n - \log \log \rho)$ rounds. All bounds are asymptotically tight and hold with high probability, i.e. $1- n^{-O(1)}$.Comment: extended abstract accepted for ALGOSENSORS 201

CONDENSATION OF ETHYL ACETOACETATE WITH NAPHTHALENE-DIOLS - THE SYNTHESIS OF SOME NOVEL COUMARINS AND CHROMONES .1.

In Simonis reaction with ethyl acetoacetate naphthalene-2,6-diol gives 8-hydroxy-3-methyl-1 H-naphtho[2,1-b]pyran-l-one and naphthalene-2,7-diol gives the related 9-hydroxy isomer. In Pechman reactions, the former diet yields a coumarin, 8-hydroxy-1-methyl-3H-naphtho[2,1-b]-pyran-3-one, with the corresponding orientation, but the latter diol gives a coumarin, 8-hydroxy-4-methyl-2H-naphtho[2,3-b]-pyran-2-one, with an unusual linear annelation pattern

Fluorescence emission and photooxidation studies with 5,6-and 6,7-benzocoumarins and a 5,6-benzochromone under direct and concentrated sun

WOS: 0001787825000214-Methyl-8-hydroxy-benzo(6,7)coumarin, 1,4-methyl-6-hydroxy-benzo(5,6)coumarin, II, and 2-methyl-6-hydroxy-benzo(5,6)chromone, III, have shown similar absorption and fluorescence emission spectra. Fluorescence emission quantum yields for I and III are found to be very low, phi(f) = 0.02, but 4-methyl-6-hydroxy-benzo(5,6)coumarin, II, has a eight-fold higher fluorescence quantum yield of the other two specie, in acetonitrile solution, of = 0.16. Quenching of anthracene fluorescence emission by 1, II and III are found to give k(q) values of 1.0 x 10(7)-1.2 x 10(9) M-1 s(-1). Benzo(5,6)coumarin, II, which gives the most intense fluorescence also presents the highest quenching rate, k(q) = 1.2 x 10(9) M-1 s(-1). Experimentally determined k(q) values are seen to correlate well with the free energy of electron transfer (DeltaG(ET)) which are calculated to be in the range of -8.0 to -9.4 kcal/mol, where benzo(5,6)coumarin, II, gives the lowest free energy of electron transfer DeltaG(ET) = -9.4 kcal/mol. These results indicate that I-III behave as electron acceptor moieties toward a condensed aromatic ring, anthracene. The Stokes shift values of 88-105 mm and broad fluorescence emission bands respect to absorption-excitation bands, indicates a molecular structure change in the excited states of I-III. Fluorescence lifetimes of 0.1-0.9 ns in I-III, singlet oxygen quantum yields of 0.15 and 0.40 for I and II, respectively, may be taken as evidence of singlet-triplet intersystem crossings. The photooxidation products of alpha-terpinene, sensitised by II, under direct and concentrated sun light conditions that are mainly p-cymene and ascaridole. In accordance with literature data on coumarin derivatives, benzocoumarins also seem to produce singlet oxygen and beside singlet oxygen, in addition super oxide anion radical production appear to be dominant especially under concentrated sun light. Under direct sun light conditions ascaridole is the major product. Some by-products of alpha-terpinene photooxidation are also determined at GC-MS analysis. Those by-products are assumed to be generated from ascaridole decomposition. (C) 2002 Elsevier Science B.V All rights reserved

New Geosite Candidates at the Western Termination of the Büyük Menderes Graben and their Importance on Science Education

The Buyuk Menderes Graben (BMG) is one of the best-known and the largest geological structure of the West Anatolian Extensional Province. It includes two nature conservation parks and twelve cultural heritage sites within and in its vicinity. Four geologically distinct features/locations within and in the vicinity of the BMG have been previously enlisted as geosite candidates in the provisional Geological Heritage Inventory of Turkey compiled in 2002 by the Turkish Association for the Conservation of the Geological Heritage (JEMRKO): (1) the horst-graben structure of the Buyuk Menderes region itself, (2) the tafoni from the augen-gneiss from the east of Bafa Lake, (3) the zultanite crystals from the northeast of lbir Mountain, and (4) the tourmaline (dravite) crystals from the Camzal, Cine. In the current study, we are introducing additional three new geosite candidates at the western termination of the BMG with three different main geological subjects. The first one is the Yavansu Fault. Located 2 km south of the Kuadas village, it has a clearly exposed unique fault surface which is one of the best examples of structural indicators for the WAEP with respect to the normal faulting events. The second one is located in the Hisartepe Volcanics exposed between Kuadas and Soke, and consists of basaltic lava flows with remarkable prismatic cooling joints and a gorgeous feeder dome reaching up to 150 m height. Final suggestion is the Karina marine fan-delta complex located at the south-eastern border of the Dilek Peninsula National Park. This fan-delta complex is the largest one in the Western Anatolian scale and has remarkable paragon outcrops up to 20 m high between Doanbey and Karina Lagoon

Chromone: A valid scaffold in medicinal chemistry

Chromones are a group of naturally occurring compounds that are ubiquitous in nature, especially in plants. The word chromone is derived from the Greek word chroma, meaning “color”, which point out that many chromone derivatives can exhibit a diversity of colors.This work was supported by the Foundation for Science and Technology (FCT), Portugal (projects PTDC/QUI-QUI/113687/2009 and PEst-C/QUI/UI0081/2013). A.G. (SFRH/BD/43531/2008) and M.J.M. (SFRH/BD/61262/2009) thank FCT for grants