Non-thermal photons and H2 formation in the early Universe

The cosmological recombination of H and He at z \sim 1000 and the formation of H2 during the dark ages produce a non-thermal photon excess in the Wien tail of the cosmic microwave background (CMB) blackbody spectrum. Here we compute the effect of these photons on the H- photodetachment and H2+ photodissociation processes. We discuss the implications for the chemical evolution of the Universe in the post-recombination epoch, emphasizing how important a detailed account of the full vibrational manifold of H2 and H2+ in the chemical network is. We find that the final abundances of H2, H2+, H3+ and HD are significantly smaller than in previous calculations that neglected the effect of non-thermal photons. The suppression is mainly caused by extra hydrogen recombination photons and could affect the formation rate of first stars. We provide simple analytical approximations for the relevant rate coefficients and briefly discuss the additional effect of dark matter annihilation on the considered reaction rates.Comment: 10 pages, 12 figures, 1 table; accepted for publication in MNRA

Novel perspectives in redox biology and pathophysiology of failing myocytes: modulation of the intramyocardial redox milieu for therapeutic interventions - A review article from the Working Group of Cardiac Cell Biology, Italian Society of Cardiology

The prevalence of heart failure (HF) is still increasing worldwide, with enormous human, social, and economic costs, in spite of huge efforts in understanding pathogeneticmechanisms and in developing effective therapies that have transformed this syndrome into a chronic disease. Myocardial redox imbalance is a hallmark of this syndrome, since excessive reactive oxygen and nitrogen species can behave as signaling molecules in the pathogenesis of hypertrophy and heart failure, leading to dysregulation of cellular calcium handling, of the contractile machinery, of myocardial energetics and metabolism, and of extracellular matrix deposition. Recently, following new interesting advances in understanding myocardial ROS and RNS signaling pathways, new promising therapeutical approaches with antioxidant properties are being developed, keeping in mind that scavenging ROS and RNS tout court is detrimental as well, since these molecules also play a role in physiological myocardial homeostasis

Modeling and predicting temporal patterns of web content changes

AbstractThe technologies aimed at Web content discovery, retrieval and management face the compelling need of coping with its highly dynamic nature coupled with complex user interactions. This paper analyzes the temporal patterns of the content changes of three major news websites with the objective of modeling and predicting their dynamics. It has been observed that changes are characterized by a time dependent behavior with large fluctuations and significant differences across hours and days. To explain this behavior, we represent the change patterns as time series. The trend and seasonal components of the observed time series capture the weekly and daily periodicity, whereas the irregular components take into account the remaining fluctuations. Models based on trigonometric polynomials and ARMA components accurately reproduce the dynamics of the empirical change patterns and provide extrapolations into the future to be used for forecasting

Secret Key Generation Based on AoA Estimation for Low SNR Conditions

In the context of physical layer security, a physical layer characteristic is used as a common source of randomness to generate the secret key. Therefore an accurate estimation of this characteristic is the core for reliable secret key generation. Estimation of almost all the existing physical layer characteristic suffer dramatically at low signal to noise (SNR) levels. In this paper, we propose a novel secret key generation algorithm that is based on the estimated angle of arrival (AoA) between the two legitimate nodes. Our algorithm has an outstanding performance at very low SNR levels. Our algorithm can exploit either the Azimuth AoA to generate the secret key or both the Azimuth and Elevation angles to generate the secret key. Exploiting a second common source of randomness adds an extra degree of freedom to the performance of our algorithm. We compare the performance of our algorithm to the algorithm that uses the most commonly used characteristics of the physical layer which are channel amplitude and phase. We show that our algorithm has a very low bit mismatch rate (BMR) at very low SNR when both channel amplitude and phase based algorithm fail to achieve an acceptable BMR

How to monitor and evaluate quality in adaptive heritage reuse projects from a well-being perspective: a proposal for a dashboard model of indicators to support promoters

Among the research discourse concerning cultural heritage in the post-COVID-19 phase, a greater awareness of the social value of heritage and its repercussions on collective well-being has emerged. This attention requires overcoming the top-down approach of public policies in favour of public–private partnership tools that are more effective at capturing the multidimensional components of value generated by cultural heritage. However, it is necessary to refine the tools used to evaluate and guide actions towards a perspective capable of integrating the conservation needs of the asset with collective well-being. This contribution investigates the calls for funding and public notices on the architectural heritage in Italy in the period from 2014–2020. In this field, the Third Sector is assuming a crucial role, showing specific attention to the issue of well-being consistent with its social goals. The calls were collected and structured in a database, with a specific focus on the calls aimed at adaptive heritage reuse that were categorised and analysed. Finally, the research proposed an assessment method based on a dashboard model of indicators to evaluate the quality of reuse interventions. The selected indicators consider both the production of plus-value in terms of improving well-being, and the need to bring the interventions on the existing architecture to a procedural circularity in line with the theoretical orientations of restoration

Determination of pesticides in the respirable fraction of airborne particulate matter by high-performance liquid chromatography–tandem mass spectrometry

Potential harmful effects of pesticides include risks to human health of workers involved in the wet spray application in cultivated areas. Inhalation exposure depends on several factors including pesticide concentrations in the respirable fraction of airborne particulate matter (PM4). To ensure a high level of protection, the use of tractors with cabins provides protection against dust, aerosols, and vapors. Since tractors not providing maximum protection are still in use, PM4 was sampled during spreading operations in agricultural fields inside and outside tractor cabins. Sample preparation technique based on accelerated solvent extraction and solid-phase extraction cleanup was optimized before analysis of nine pesticides in PM4. Meptyldinocap, deltamethrin, myclobutanil, fluopyram, methoxyfenozide, dimethomorph, fluopicolide, cyflufenamid, and metrafenone were simultaneously determined by high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC–ESI–MS–MS). The results demonstrated the efficacy of the tractor cabs used in the sampling sites. © 2017 Taylor & Francis

Smoke, alcohol and drug addiction and male fertility

In recent decades, the decline in human fertility has become increasingly more worrying: while therapeutic interventions might help, they are vexing for the couple and often burdened with high failure rates and costs. Prevention is the most successful approach to fertility disorders in males and females alike. We performed a literature review on three of the most common unhealthy habits - tobacco, alcohol and drug addiction - and their reported effects on male fertility. Tobacco smoking is remarkably common in most first-world countries; despite a progressive decline in the US, recent reports suggest a prevalence of more than 30% in subjects of reproductive age - a disturbing perspective, given the well-known ill-effects on reproductive and sexual function as well as general health. Alcohol consumption is often considered socially acceptable, but its negative effects on gonadal function have been consistently reported in the last 30 years. Several studies have reported a variety of negative effects on male fertility following drug abuse - a worrying phenomenon, as illicit drug consumption is on the rise, most notably in younger subjects. While evidence in these regards is still far from solid, mostly as a result of several confounding factors, it is safe to assume that cessation of tobacco smoking, alcohol consumption and recreational drug addiction might represent the best course of action for any couple trying to achieve pregnancy

Influencia de nanotubos de carbono em camadas ativas de dispositivos fotodetectores orgânicos

Orientadora: Lucimara Stolz RomanInclui apendiceDissertaçao (mestrado) - Universidade Federal do Paraná, Setor de Ciencias Exatas, Programa de Pós-Graduaçao em Física. Defesa: Curitiba, 2004Inclui bibliografi

Dispositivos fotovoltaicos orgânicos : estudo de camadas ativas e eletrodos

Orientadora: Profa. Dra. Lucimara Stoltz RomanTese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduaçao em Engenharia - PIPE. Defesa: Curitiba, 05/03/2010Bibliografia: fls. 102-103Área de concentraçao: Engenharia e ciencia dos materiaisResumo: Neste trabalho, apresentamos os estudos de eletrodos e camadas ativas no desenvolvimento de células solares orgânicas. O óxido de estanho (SnO ) apresenta características interessantes para a aplicação como eletrodo transparente: quando depositado em um substrato de vidro formando filme fino, apresenta-se semi-transparente ao espectro da luz visível e é capaz de conduzir eletricidade. A otimização das características elétricas é feita pela dopagem do óxido com flúor. Apresentamos resultados experimentais e teóricos na caracterização dos óxidos sem dopagem, com dopagem moderada e alta dopagem de flúor. Os dispositivos fotovoltaicos orgânicos foram caracterizados tendo como base dois polímeros conjugados: o politiofeno (PT) e um novo derivado de tiofeno, Poli(9,9'-dioctil-2,7-fluorenodiilvinileno-co-5,5’-(benzo[1,2,5]tiadiazol- 4,7diil)ditiofeno)(PFTBT). A deposição da camada ativa do primeiro polímero é feita por eletroquímica e os dispositivos foram feitos em estutura monocamda, apresentando bons resultados para eficiência quântica externa. A fabricação de dispositivos fotodectores permitiu a aplicação tecnológica dos dispositivos em matrizes de detecção posicional. As camadas ativas geradas pelo segundo polímero foram obtidas pelo processo de deposição por centrifugação de solução. Os resultados fotovoltaicos são apresentados em três estruturas diferentes: monocamada, bicamada e heterojunção de volume. Os dispositivos bicamada revelam-se mais eficiêntes que os de heterojunção. Uma das verificações desta diferença está na estimativa para a taxa de éxcitons gerados na camada ativa:este valor é maior para o caso de heterojunção, no entanto, a probabilidade destas cargas se dissociarem é menor quando comparada a dispositivos bicamada. Alguns nanocompósitos também foram estudados para a aplicação em fotovoltaicos: misturas de polímero conjugado com nanotubos de carbono e misturas de polímero conjugado com nanopartículas de ouro. No primeiro caso, dois polímeros foram estudados, o comerical Poli(3-hexil tiofeno) (P3HT) e o não-comercial Poli(9,9-dihexilfluorenodiil- vinileno-alt-1,4-fenilenovinileno) (PDHFPPV). A interação entre os diferentes polímeros e os nanotubos de carbono são apresentadas em termos da caracterização óptica e elétrica. A inserção de nanopartículas de ouro na matriz do polímero P3HT revela a diminuição de eficiência de foto-conversão quando estes materiais são estudados como camadas ativas em dispositivos fotovoltaicos. Este fato pode estar associado à dificuldade na transferência de cargas das nanopartículas para o polímero, devido a este apresentar camada passivadora de dodecanotióis.Abstract: In this work, we present studies of electrodes and active layers in the development of organic solar cells. The tin oxide (SnO2) presents interesting features for application as transparent electrode: when deposited on a glass substrate to form thin film, presents semi-transparent to visible light spectrum and is capable of conducting electricity. The optimization of electrical characteristics is made by doping the oxide with fluorine. We present experimental results and theoretical characterization of the oxides without doping, moderate doping and high doping of fluorine. The organic photovoltaics have been characterized based on two conjugated polymers: the polythiophene (PT) and a new derivative of thiophene, the poly (9,9 '- dioctyl-2 ,7-fluorenedyilvinylene-co-5, 5'-(benzo [ 1,2,5] thiadiazole-4, 7dyil) dithiophene) (PFTBT). The deposition of the active layer of the first polymer is made by electrochemistry and the devices were made in monolayer structure, showing good results for external quantum efficiency. The fabrication of fotodetectors devices allowed the application of technological devices in arrays of positional detection. The active layers generated by the second polymer were obtained by chemical deposition. Photovoltaic results are presented in three different structures: monolayer, bilayer and bulk heterojunction. Bilayer devices appear more efficient than the bulk heterojunction. One of the findings of this difference is the estimate for the rate of excitons generated in the active layer: this value is larger for the heterojunction case, however, the probability to exciton dissociation in free charges is lower when compared to bilayer devices. Nanocomposites were also studied for application in photovoltaics: mixtures of conjugated polymer with carbon nanotubes and mixtures of conjugated polymer with gold nanoparticles. Two polymers were studied in the first case, the commercial Poly (3- hexyl thiophene) (P3HT) and non-commercial poly (9,9-di-hexilfluorenodiil-vinylenealt- 1 ,4-phenylenevinylene) (PDHFPPV). The interaction between different polymers and carbon nanotubes are presented in terms of optical and electrical characterization. The insertion of gold nanoparticles in a polymer matrix P3HT show the decrease in efficiency of photo-conversion when these materials are studied as active layers in photovoltaic devices. This may be associated with difficulty in transferring charges from nanoparticles to the polymer, due to the passivating layer capping the nanoparticles