Absorption spectra of poly-N-vinylcarbazole derivatives by experiment and simulation

Geometry molecular optimization and quantum chemical simulations of absorption spectra for newly synthesized poly-N-vinylcarbazole derivatives were performed using a semi-empirical approach. The studied polymers were modified by changing the positions of the carbazole group with respect to the polymer backbone. The absorption spectra were calculated for different numbers of PNVK monomers. A sufficient agreement between the calculated and experimentally measured spectra was observed. A change of the red shift absorption with respect to the blue shift was observed for cases when the number of monomers was higher than 4. The theoretical simulations indicate that this behavior is a consequence of the specific molecular structure of the considered molecules. The results demonstrate the potential of combined simulation and experimental studies in materials engineering and searching of new electro-luminescent materials

Predicting growth and development of pigeonpea: leaf area development

Relationships are developed that describe the processes of node production, leaf appearance and senescence, and leaf size in pigeonpea in relation to temperature, plant density and maturity type. The rate of node production until owering in relation to thermal time was found to be unaffected by season and plant density in the range of 4±33 plants mÿ2. Maturity type did not affect the rate of node production on the main stem or the rate of appearance of leaves on the plant. The rate of senescence of main-stem nodes in relation to thermal time was unaffected by plant density and growth duration. The functions developed in this paper can be used to predict the temporal changes in leaf area development in crop growth models

(Photo)physical properties of new molecular glasses end-capped with thiophene rings composed of diimide and imine units

New symmetrical arylene bisimide derivatives formed by using electron-donating-electron-accepting systems were synthesized. They consist of a phthalic diimide or naphthalenediimide core and imine linkages and are end-capped with thiophene, bithiophene, and (ethylenedioxy)thiophene units. Moreover, polymers were obtained from a new diamine, N,N′-bis(5- aminonaphthalenyl)naphthalene-1,4,5,8-dicarboximide and 2,5- thiophenedicarboxaldehyde or 2,2′-bithiophene-5,5′-dicarboxaldehyde. The prepared azomethine diimides exhibited glass-forming properties. The obtained compounds emitted blue light with the emission maximum at 470 nm. The value of the absorption coefficient was determined as a function of the photon energy using spectroscopic ellipsometry. All compounds are electrochemically active and undergo reversible electrochemical reduction and irreversible oxidation processes as was found in cyclic voltammetry and differential pulse voltammetry (DPV) studies. They exhibited a low electrochemically (DPV) calculated energy band gap (Eg) from 1.14 to 1.70 eV. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels and Eg were additionally calculated theoretically by density functional theory at the B3LYP/6-31G(d,p) level. The photovoltaic properties of two model compounds as the active layer in organic solar cells in the configuration indium tin oxide/poly(3,4-(ethylenedioxy)thiophene):poly(styrenesulfonate)/active layer/Al under an illumination of 1.3 mW/cm2 were studied. The device comprising poly(3-hexylthiophene) with the compound end-capped with bithiophene rings showed the highest value of Voc (above 1 V). The conversion efficiency of the fabricated solar cell was in the range of 0.69-0.90%

Comparative physical maps derived from BAC end sequences of tilapia (Oreochromis niloticus)

Background: The Nile tilapia is the second most important fish in aquaculture. It is an excellent laboratory model, and is closely related to the African lake cichlids famous for their rapid rates of speciation. A suite of genomic resources has been developed for this species, including genetic maps and ESTs. Here we analyze BAC endsequences to develop comparative physical maps, and estimate the number of genome rearrangements, between tilapia and other model fish species. Results: We obtained sequence from one or both ends of 106,259 tilapia BACs. BLAST analysis against the genome assemblies of stickleback, medaka and pufferfish allowed identification of homologies for approximately 25,000 BACs for each species. We calculate that rearrangement breakpoints between tilapia and these species occur about every 3 Mb across the genome. Analysis of 35,000 clones previously assembled into contigs by restriction fingerprints allowed identification of longer-range syntenies. Conclusions: Our data suggest that chromosomal evolution in recent teleosts is dominated by alternate loss of gene duplicates, and by intra-chromosomal rearrangements (~one per million years). These physical maps are a useful resource for comparative positional cloning of traits in cichlid fishes. The paired BAC end sequences from these clones will be an important resource for scaffolding forthcoming shotgun sequence assemblies of the tilapia genome. (Résumé d'auteur

The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni

Color and pigmentation patterns of animals are often targets of sexual selection because of their role in communication. Although conspicuous male traits are typically implicated with intersexual selection, there are examples where sex-specific displays play a role in an intrasexual context, e.g. when they serve as signals for aggression level and/or status. Here, we focus on the function of a conspicuous male ornament in the most species-rich tribe of cichlid fishes, the haplochromines. A characteristic feature of these ca. 1500 species are so-called egg-spots in form of ovoid markings on the anal fins of males, which are made up of carotenoid based pigment cells. It has long been assumed that these yellow, orange or reddish egg-spots play an important role in the courtship and spawning behavior of these maternal mouth-brooding fishes by mimicking the eggs of a conspecific female. The exact function of egg-spots remains unknown, however, and there are several hypotheses about their mode of action. To uncover the function of this cichlid-specific male ornament, we used female mate choice experiments and a male aggression test in the haplochromine species Astatotilapia burtoni. We manipulated the number and arrangement of egg-spots on the anal fins of males, or removed them entirely, and tested (1) female preference with visual contact only using egg-traps, (2) female preference with free contact using paternity testing with microsatellites and (3) male aggression. We found that females did not prefer males with many egg-spots over males with fewer egg-spots and that females tended to prefer males without egg-spots over males with egg-spots. Importantly, males without egg-spots sired clutches with the same fertilization rate as males with egg-spots. In male aggression trials, however, males with fewer egg-spots received significantly more attacks, suggesting that egg-spots are an important signal in intrasexual communication

Physical-mechanical properties of limestones from the Szachownica Cave

W artykule przedstawiono wyniki prac mających na celu poznanie fizyko-mechanicznych własności wapieni budujących jaskinię Szachownica, która jest drugim, co do wielkości siedliskiem nietoperzy w Polsce. Jaskinia pod wpływem działania czynników naturalnych oraz działalności człowieka podlega zaawansowanemu procesowi destrukcji. W oparciu o wyniki przeprowadzonych badań laboratoryjnych i pomiarów in situ sporządzono ekspertyzę dla Śląskiego Urzędu Wojewódzkiego. W ekspertyzie zaproponowano kilka wariantów zabezpieczenia jaskini, które mają na celu powstrzymanie postępującego procesu niszczenia jaskini i zachowania jej w stanie umożliwiającym pełnienie dotychczasowej jej funkcji w środowisku.In the paper, results were presented of works targeted on recognition of physical-mechanical properties of limestones forming Szachownica Cave being the second bat settlement in Poland with respect to its size. The cave is subjected to an advanced process of destruction under impact of natural factors as well as human activities. An opinion was developed for Silesian Voivodeship Office on the basis of laboratory tests and in situ measurements conducted. In the opinion, several variants of cave protection were proposed targeted on stopping of the cave destruction advancing process and preserving the cave in a state enabling a fulfillment of its functions it has been playing so far in the environment

Mega-Events and Heritage: The Experience of Five European Cities

In the past, many cities used mega-events as a strategy to boost development. The creation of new facilities and infrastructures for mega-events typically targeted areas of expansion outside of historic city fabric. Today, on the contrary, mega-event organizers are increasingly opting more for the re-use of existing facilities and areas. This paradigm shift represents both a potential opportunity and threat for heritage-rich cities in Europe. This book explores the relationships between the planning and implementation of mega-events and cultural heritage through the in-depth study of five cases: Genoa 2004 European Capital of Culture, Milan Expo 2015, Wrocław 2016 European Capital of Culture, Hull 2017 UK City of Culture, Pafos 2017 European Capital of Culture. The book draws on these case studies in order to spark further research and policy debate regarding the emerging opportunities and threats for context-specific policies and projects, for long-term urban development, for cooperation among actors and capacity building at different levels, for the multiple social and cultural identities that help heritage and cities to flourish