Resonant third harmonic generation of KrF laser in Ar gas

Investigations of emission of harmonics from argon gas jet irradiated by 700 fs, 5 mJ pulses from a KrF laser are presented. Harmonics conversion was optimized by varying the experimental geometry and the nozzle size. For the collection of the harmonic radiation silicon and solar-blind diamond semiconductor detectors equipped with charge preamplifiers were applied. The possibility of using a single-crystal CVD diamond detector for separate measurement of the 3rd harmonic in the presence of a strong pumping radiation was explored. Our experiments show that the earlier suggested 0.7% conversion efficiency can really be obtained, but only in the case when phase matching is optimized with an elongated gas target length corresponding to the length of coherence

Progress on lead-free metal halide perovskites for photovoltaic applications: a review

ABSTRACT: Metal halide perovskites have revolutionized the field of solution-processable photovoltaics. Within just a few years, the power conversion efficiencies of perovskite-based solar cells have been improved significantly to over 20%, which makes them now already comparably efficient to silicon-based photovoltaics. This breakthrough in solution-based photovoltaics, however, has the drawback that these high efficiencies can only be obtained with lead-based perovskites and this will arguably be a substantial hurdle for various applications of perovskite-based photovoltaics and their acceptance in society, even though the amounts of lead in the solar cells are low. This fact opened up a new research field on lead-free metal halide perovskites, which is currently remarkably vivid. We took this as incentive to review this emerging research field and discuss possible alternative elements to replace lead in metal halide perovskites and the properties of the corresponding perovskite materials based on recent theoretical and experimental studies. Up to now, tin-based perovskites turned out to be most promising in terms of power conversion efficiency; however, also the toxicity of these tin-based perovskites is argued. In the focus of the research community are other elements as well including germanium, copper, antimony, or bismuth, and the corresponding perovskite compounds are already showing promising properties. GRAPHICAL ABSTRACT: [Image: see text

Neural processing of natural sounds

Natural sounds include animal vocalizations, environmental sounds such as wind, water and fire noises and non-vocal sounds made by animals and humans for communication. These natural sounds have characteristic statistical properties that make them perceptually salient and that drive auditory neurons in optimal regimes for information transmission.Recent advances in statistics and computer sciences have allowed neuro-physiologists to extract the stimulus-response function of complex auditory neurons from responses to natural sounds. These studies have shown a hierarchical processing that leads to the neural detection of progressively more complex natural sound features and have demonstrated the importance of the acoustical and behavioral contexts for the neural responses.High-level auditory neurons have shown to be exquisitely selective for conspecific calls. This fine selectivity could play an important role for species recognition, for vocal learning in songbirds and, in the case of the bats, for the processing of the sounds used in echolocation. Research that investigates how communication sounds are categorized into behaviorally meaningful groups (e.g. call types in animals, words in human speech) remains in its infancy.Animals and humans also excel at separating communication sounds from each other and from background noise. Neurons that detect communication calls in noise have been found but the neural computations involved in sound source separation and natural auditory scene analysis remain overall poorly understood. Thus, future auditory research will have to focus not only on how natural sounds are processed by the auditory system but also on the computations that allow for this processing to occur in natural listening situations.The complexity of the computations needed in the natural hearing task might require a high-dimensional representation provided by ensemble of neurons and the use of natural sounds might be the best solution for understanding the ensemble neural code

ANKLE ULTRASOUND TENOSYNOVITIS IS A SIGNIFICANT PREDICTOR OF DAS28 – DEFINED RHEUMATOID ARTHRITIS ACTIVITY

Objective. The study aimed to observe the frequency of ultrasound-defined tenosynovitis in ankle tendon and to evaluate the relationship of ankle tenosynovitis with clinical examination and rheumatoid arthritis (RA) activity measures. Methods. RA patients were recruited in 2018 in the random order of presentation from the out-patient clinic. On the same day of inclusion, all patients underwent clinical examination, laboratory tests (inflammatory markers), ankle ultrasound and patient-reported outcomes. Results. the study included 183 patients with established RA, mostly women (86.3%), with mean age of 57.3 years. The most frequent tenosynovitis was observed in the tibialis posterior tendon (TP; 40.4%), followed by the peroneus longus (23.0%) and peroneus brevis (18.0%) tendons. Compared to patients without TP tenosynovitis, patients with TP tenosynovitis had significantly higher titres of rheumatoid factors (RF; median of 123 IU/mL compared to 64 IU/mL; p = 0.023). Clinically tender (55.2%) and swollen (30.6%) ankles were 4.2 and respectively 11.6 times more likely to reveal tenosynovitis on ultrasound. The presence of ankle tenosynovitis was associated with higher disease activity measures. DAS28 increased proportionally and significantly with the number of ankles with tenosynovitis, the grade of ankle tenosynovitis and power Doppler activity. The absence of ankle tenosynovitis independently and significantly decreased DAS28 with 1.2 points (p < 0.001). Conclusions. the most frequent ankle tenosynovitis observed in RA patients involves the TP tendon, which is associated with higher titres of RF. Swollen ankles are more specific and better predictors of ultrasound-defined ankle tenosynovitis, which has a directly proportional relationship with disease activity in RA. Disease activity scores should include clinical evaluation of ankles and ultrasound information

Bonding Scheme and Optical Properties in BiM 2 O 2 (PO 4 ) (M=Cd, Mg, Zn); Experimental and Theoretical Analysis

International audienc

Underwater Muse. Il parimonio è di tutti (anche sott'acqua)

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