Sygnalizacja wyników finansowych w polityce dywidendowej na rynku NewConnect

The aim of the paper was to give evidence whether changes of dividends could be considered as signals forecasting changes in future financial results. The sample consists of 42 companies listed on the NewConnect market in the years 2007–2016, paying regular dividends for at least 3 years. Using linear regression models, we show that dividend changes have a weak but positive effect on revenues changes, but they are insignificant when explaining changes in operating performance and net income. The paper fills a gap in empirical research on the Polish stock market, and especially the signalling function of dividends on NewConnect, which is characterised by a high degree of information asymmetry, has been examined for the first time.Celem artykułu jest sprawdzenie, czy zmiany w poziomie wypłacanych dywidend można uznać za informacje sygnalizujące zmiany w przyszłych wynikach finansowych (przychodach, zyskach operacyjnych, wyniku netto). Próba dotyczy 42 spółek notowanych na rynku NewConnect w latach 2007–2016, wypłacających regularnie dywidendę przez co najmniej 3 lata. Wykorzystując modele regresji liniowej, pokazano, że zmiany w poziomie wypłacanych dywidend pozytywnie wpływają na zmiany w przychodach, jednak w sposób nieistotny wyjaśniają zmiany wyników operacyjnych i wyników netto. Praca wypełnia lukę w badaniach empirycznych nad polskim rynkiem akcji – w szczególności po raz pierwszy zbadano funkcję sygnalizacyjną dywidend na rynku NewConnect, który charakteryzuje się wysokim poziomem asymetrii informacji

Polyphyly of the extinct family Oviparosiphidae and its implications forinferring aphid evolution (Hemiptera, Sternorrhyncha)

Aphidoidea, the so-called "true aphids" are one of the most challenging groups in terms of solving the phylogenetic relationships. Morphology-based analyses were strongly affected by widespread homoplasy, while the molecular-based attempts struggled with the lack of sufficient phylogenetic signal. Despite significant improvements, the higher classification still remains unresolved and rather controversial. However, the use of the fossil record, one of the most valuable sources of information, was mainly limited to calibration of a phylogenetic tree, without a direct inclusion into the analysis. The extinct family Oviparosiphidae has long been considered as the common ancestor of all recent Aphidoidea and it was used as a calibration point in several analyses, but it has been never analyzed in a phylogenetic context. The family has been treated as a monophyletic group purely based on the simultaneous presence of two abdominal structures, ovipositor and siphunculi. However, it has been shown recently that at least one more extinct lineage, present at the same time, was characterized by the same features. For these reasons, we performed a maximum parsimony analysis using morphological data for extinct aphid taxa to prove the monophyly of Oviparosiphidae. Our analysis shows that the presumed ancestor lineage of recent aphids is a polyphyletic group. Our results support the hypothesis of an early Mesozoic rapid radiation of aphids, which led to several different lineages characterized by both ovipositor and siphunculi. The results indicate the necessity of examining the other extinct families, and shows that the diversity of aphids before the Cretaceous Terrestrial Revolution (KTR) was higher than expected. Even though there is not enough data to perform a formal analysis, fossils seem to suggest a significant impact of the KTR on aphid diversification. Additionally, we have made a redescription of two genera and description of a new species, Vitimaphis subridens sp. nov

Genetic data of museum specimens allow for inferring evolutionary history of the cosmopolitan genus Sirthenea (Heteroptera: Reduviidae)

Among the 30 known genera within subfamily Peiratinae, only the genus Sirthenea has a cosmopolitan distribution. The results of our studies are the first comprehensive analysis concerning one of the representatives of mentioned subfamily based on joint phylogenetic analyses ofmolecular andmorphological data as well asmolecular dating. A total of 32 species were included into the dataset with all known species of the genus Sirthenea. Material of over 400 dry specimens was examined for the morphological part of this study. The cosmopolitan distribution of Sirthenea and the inaccessibility of specimens preserved in alcohol required the extraction of DNA from the dried skeletal muscles of specimens deposited in 24 entomological collections. The oldest specimens used for the successful extraction and sequencing were collected more than 120 years ago in India. We performed Bayesian Inference analyses of molecular and morphological data separately, as well as combined analysis. The molecular and morphological data obtained during our research verify the correlation of the divergence dates of all known Sirthenea species. Results of the relaxed molecular clock analysis of the molecular data show that, the genus Sirthenea started diverging in the Late Cretaceous into two clades, which subsequently began to branch off in the Paleocene. Our results of phylogenetic analyses suggest that the fossula spongiosa and its development could be one of the most important morphological characters in the evolution of the genus, most likely associated with the ecological niche inhabited by Sirthenea representatives. Confirmation of the results obtained in our studies is the reconciliation of the evolutionary history of Sirthenea with the biogeographical processes that have shaped current global distribution of the genus

Dependence of viscosity of suspensions of ceramic nanopowders in ethyl alcohol on concentration and temperature

This work presents results of measurements of viscosity of suspensions including yttrium oxide (Y(2)O(3)), yttrium aluminum garnet (Y(3)Al(5)O(12)) and magnesium aluminum spinel (MgAl(2)O(4)) nanopowders in ethanol. Nanoparticles used in our research were either commercially available (Baikowski) or nanopowders newly developed in the Institute of Ceramics and Building Materials in Warsaw, Poland. The study was conducted in a wide range of shear rates (0.01 to 2,000 s(−1)) and temperature interval from -15°C to 20°C. A Haake Mars 2 rheometer from Thermo Fisher, Germany, was used in the Biophysics Laboratory at Rzeszów University of Technology. Most of the samples show a non-Newtonian behaviour. It was confirmed with a Rheo-NMR system from Bruker that 10% by weight of Y(2)O(3) suspension is a non-Newtonian fluid. In this work, we also report an unexpected behaviour of the viscosity of some samples (Y(2)O(3) and Y(3)Al(5)O(12)) due to sedimentation effect

Trabecular bone score (TBS) as a noninvasive and complementary tool for clinical diagnosis of bone structure in endocrine disorders

Trabecular bone score (TBS) index has recently been obtained as a result of textural greyscale analysis of DXA images. Because it enables the assessment of bone microarchitectural texture, TBS may be useful in evaluating bone quality. This study explores the current knowledge of the use of TBS in patients with endocrine disorders with co-occurring bone structure changes. Currently, the clinical importance TBS was verified in terms of disorders of the growth hormone/insulin-like growth factor 1 (GH/IGF-I) axis, glucocorticoid excess, thyroid and parathyroid disease, as well as in diabetes mellitus type 1 and 2.It has been clarified that patients suffering from various endocrinopathies are a group in which TBS should be used routinely because it correlates with clinical factors and may improve patient management in various endocrine disorders.

SIMPLIFIED GRAPHICAL DOMAIN-SPECIFIC LANGUAGES FOR THE MOBILE DOMAIN – PERSPECTIVES OF LEARNABILITY BY NONTECHNICAL USERS

Increasing number of technologically advanced mobile devices causes the need for seeking methods of software development that would involve persons without or with highly limited programming skills. They could participate as domain experts or individual creators of personal appli-cations. Methods based on models might be the right answer, thus the author conducted workshops and surveys concerning perspectives of gra-phical modeling languages for the mobile domain. Research revealed that nontechnical users declared high learnability of simplified ones as well as the majority of them correctly read models in such languages

WYDAJNOŚĆ IMPLEMENTACJI PODSTAWOWYCH METOD CAŁKOWANIA W ŚRODOWISKU APP INVENTOR

This paper presents comparison of efficiency of basic integration methods implemented in App Inventor and Java for Android environment. Chosen methods (rectangle, trapezoidal and Simpson’s rules) were applied for linear, cubic and sine functions. Conducted experiment revealed that applications developed in App Inventor were significantly slower than in case of Java, which makes App Inventor unsuitable for applications involving intensive calculations.W niniejszym artykule dokonano porównania wydajności podstawowych metod całkowania zaimplementowanych w środowisku App Inventor oraz Java dla platformy Android. Wybrane metody (prostokątów, trapezów i Simpsona) zastosowano dla funkcji liniowej, sześciennej oraz sinusoidy. Rezultaty eksperymentu wykazały, że działanie algorytmów zaimplementowanych w App Inventor jest wielokrotnie wolniejsze niż w Java dla Android, co znacząco ogranicza przydatność środowiska App Inventor do tworzenia aplikacji realizujących obliczenia matematyczne

Revised concept of the fossil genus Oviparosiphum Shaposhnikov, 1979 with the description of a new genus (Hemiptera, Sternorrhyncha,Aphidomorpha)

This paper presents a revision of the aphid genus Oviparosiphum, which is known from the Cretaceous period. Redescriptions of two species: O. jakovlevi Shaposhnikov, 1979 and O. baissense Shaposhnikov & Wegierek, 1989 are made, and an updated diagnosis of this genus is provided. Oviparosiphum baissense is the type species of a newly described genus Archeoviparosiphum gen. n. Five other species of Oviparosiphum are also transferred to the new genus. The basis for their separation from Oviparosiphum is the structure of the siphunculi and ovipositor. A key is provided to the genera of Oviparosiphidae