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Number of results: 13
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Abstract

The Crassulaceae family mainly comprises herbaceous leaf succulents, some of which are used as ornamentals. The development of the embryo suspensor in Sedum reflexum L. was investigated using cytochemical methods, light and electron microscopy. The full development and functioning of the suspensor occurs during the late globular and heart-stage embryos. The suspensor consists of a large basal cell and a single row of 6-10 chalazal cells. The basal cell produces a branched haustorium which invades ovular tissues. The walls of the haustorium and the micropylar part of the basal cell form the wall ingrowths that are typical for transfer cells. The dense cytoplasm filling the basal cell is rich in profiles of endoplasmic reticulum, active dictyosomes, mitochondria, plastids, microtubules, bundles of microfilaments, microbodies and lipid droplets. The present work reveals that the suspensor structure in S. reflexum markedly differs from that found in other representatives of Crassulaceae. Ultrastructural analysis and cytochemical tests (including proteins, insoluble polysaccharides and lipids) indicate that in S. reflexum the embryo suspensor is involved mainly in absorption and transport of metabolites from the ovular tissues to the developing embryo proper via the chalazal suspensor cells.
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Abstract

We examined the development of the endosperm chalazal haustorium of Rhinanthus serotinus, using histochemical assays and light and electron microscopy. The chalazal haustorium is a huge single cell containing two enlarged nuclei. The nuclei are located in the middle of the haustorium cell. At the chalazal end of the haustorium cell structure, ultrastructural study revealed the presence of a transfer wall forming wall ingrowths. At all examined stages of haustorium cell development we identified insoluble polysaccharides, proteins, nucleic acids and lipid droplets. Macromolecules were especially abundant in the fully differentiated haustorium cell. Our results suggest that the endosperm chalazal haustorium is a site of intense metabolic activity
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Abstract

The paper presents results of numerical calculations and experimental data on the directional pattern of two 38-element parametric arrays composed of ultrasound sources. Two types of antenna arrays are considered, namely with parallel and coaxial connections of ultrasonic transducers (elements). The results of selecting and functional testing of unit elements are described in this paper. It is found that in the coaxial element connection of the antenna array, the level of side lobes is higher than that in the parallel element connection.
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Abstract

Some consider the multiculturality of Wrocław to be its obvious and socially legitimised “property”, whereas others view it as controversial and refutable construct. In the paper, we would like to investigate the multiculturality of the Lower Silesia’s capital taking into account its internal differentiation, which is mostly due to the adjudicating authorities – city authorities, its citizens and researchers — as well as observable dynamics. Hence, we propose to inspect the following: firstly, the real differentiation of the social structure of Wrocław’s inhabitants and its transformations related mostly to the influx of Ukrainians, who change the ethnic cityscape; secondly, the politics of municipal authorities regarding the promotion and strengthening of the city’s image as the multicultural, open and tolerant “meeting place”, as well as initiatives inscribed therein and other observable, contradictory events; thirdly, the evaluation of Wrocław’s multiculturality and its selected aspects performed by the city’s inhabitants and revealed in the research on this phenomenon in 2011 and in two editions of Social Diagnosis of Wrocław (2014 and 2017).
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Abstract

Newcastle disease (ND) is a highly contagious and economically important disease in the poultry industry caused by avian avulavirus-1, historically known as Newcastle disease virus (NDV). Control of ND primarily relies on prophylactic vaccination of flocks, and many vaccines are available on the market, both conventional and more recently introduced new generation recombinant types. To assess the protection level achieved by vaccination ELISA tests are typically used, they also are to track an infection with field strains in non-vaccinated flocks. Special modifications of ELISA can be used as a screening tool to detect infection in flocks vaccinated with new generation vaccines. In this study, we have developed an ELISA test for the detection of antibodies against the nucleoprotein (NP) of NDV and for differentiation of chickens vaccinated with commercial and prototype in-house recombinant vector vaccines from those infected with field NDV strains. The NP gene of LaSota NDV strain expressed in a baculovirus vector was used as a coating antigen in the ELISA. The developed test was optimized, validated and compared to other serological tests. The sensitivity, specificity and accuracy of recombinant NP protein-based ELISA were respectively 96.1%, 96.3%, and 96.2%. Inter-rater (kappa) agreement between the NP-ELISA and the gold standard HI test was calculated to be 0.995. In our comparisons, commercially available ELISA tests revealed different specificities ranging from 95.5–100% and sensitivities at variance, ranging from 90.1 to 99.0%. A high level of maternally derived antibodies was measured in the serum of 1-day-old broilers in the NP-ELISA assay. These antibodies had disappeared and were undetected at 3, 5 and 6 weeks post-vaccination but birds became positive again at 2 weeks after control infection with a velogenic NDV strain. In SPF chickens, antibodies against NP protein were detected only after a challenge. The recombinant NP protein-based ELISA test is sensitive, specific and accurate when compared to the gold standard HI test and commercially available kits. Moreover, the method could be also used for the differentiation between vaccinated and infected birds.
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Abstract

The present report describes the new occurrence of Tomato mosaic virus (ToMV) in cabbage, bean and Malva neglecta plants in Iran. In this study, sequence analyses of a partial RNA dependent RNA polymerases (RdRp) and complete movement protein (MP) and the coat protein (CP) nucleotide sequences of three new ToMV isolates collected from major crop fields in Iran revealed low genetic variation of RdRp gene compared to the CP and MP genes. The different topologies of the phylogenetic trees constructed, using available open reading frame (ORF1), ORF2 and ORF3 sequences from ToMV isolates, indicated different evolutionary constraints in these genomic regions. Statistical analysis also revealed that with the exception of CP other tested ToMV genes were under negative selection and the RdRp gene was under the strongest constraints. According to the phylogenetic tree it can be inferred from the nucleotide sequences of the complete CP and MP genes, that isolates from Iran and Egypt formed separate groups, irrespective of host origin. However, isolates clustered into groups with correlation to geographic origin but not the host. Analysis of the Ks *, Z* and Snn values also indicated genetic differentiation between ToMV populations. The Tajima’s D, Fu and Li’s statistical values were significantly negative for the RdRp gene of the Asian population which suggests the sudden expansion of ToMV in Asia. Taken together, the results indicate that negative selection and genetic drift were important evolutionary factors driving the genetic diversification of ToMV.
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Abstract

The aim of this study was to assess the biological effect of the product Jodis Concentrate (JC) on the rabbit ovaries by evaluating the folliculogenesis and expression of oocyte-specific growth differentiation factor 9 (GDF9). The experiment was conducted with 30 female two month old New Zealand rabbits that were the F1 offspring born to mothers differently treated with Jodis concentrate. The control group (n=10), consisted of F1 offspring born to mothers without iodine treatment, and was not supple- mented with JC. The first experimental group (n=10), consisted of F1 offspring born to mothers treated with JC during pregnancy and the suckling period, and was supplemented with JC daily at a dose of 2 ml/L drinking. The second experimental group (n=10), consisted of F1 offspring born to mothers without iodine treatment, and was also supplemented daily with the same dose of JC - 2 ml/L drinking. All groups were fed with total mixed ration for growing rabbits. The trial lasted 48 days. The ovaries were weighed and prepared for histological examination. The GDF9 protein expression in the ovary was determined by immunohistochemical analysis. The addition of JC to the drinking water of female rabbits led to more active development of the ovarian follicles from primordial to tertiary stage in both experimental groups. More intensive GDF9 protein expression in the oocytes and cumulus cells of rabbits, supplemented with JC was observed.
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Abstract

Zinc (II) removal using low-cost sorbents requires a proper process parametric study to determine its optimal performance characteristics. In this respect, the present study proposes a new modeling and simulation procedure for heavy metal removal system and is carried out to optimize input variables such as initial pH, adsorbent dosage, and contact time for biosorption of Zinc (II) by using bentonite. The proposed experimental system is cost-effective and requires less calculation for determining optimal values, i.e., input variables and their related removal capacity, Rem%. To optimize the adsorption process, cubic spline curve fitting and numerical differentiation techniques are used for required calculations. According to the proposed calculations, the removal capacity is calculated as 98.66%, while the optimal values are calculated as initial pH – 6.76, adsorbent dosage – 1.14 g L-1, contact time – 13 minutes. To evaluate the results, full factor experimental design and 3 way ANOVA test are used for comparison.
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Abstract

Although the explicit commutativitiy conditions for second-order linear time-varying systems have been appeared in some literature, these are all for initially relaxed systems. This paper presents explicit necessary and sufficient commutativity conditions for commutativity of second-order linear time-varying systems with non-zero initial conditions. It has appeared interesting that the second requirement for the commutativity of non-relaxed systems plays an important role on the commutativity conditions when non-zero initial conditions exist. Another highlight is that the commutativity of switched systems is considered and spoiling of commutativity at the switching instants is illustrated for the first time. The simulation results support the theory developed in the paper.
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Abstract

The present paper discusses the new Polish law on higher education in the context of the contrasted global and academic paradigms of university funding, governance, and organization. Its point of departure is the advent of international comparative data in higher education, the measurability of individuals, academic units and institutions in terms of research output, and the emergence of a new social contract between the state and universities. The key concepts used to evaluate the new law are competition in science, academic income structure and academic knowledge production structure, internationalists and locals in science, and vertical differentiation in national higher education systems. The new law is assessed in the context of the original reform proposal suggested by the national team of experts led by the present author and its long-term strategic choices are discussed in more detail, including a changing system of institutional evaluation, a revised system of academic degrees, and new excellence-focused national funding schemes.
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Abstract

Pedunculate and sessile oaks (Quercus robur L.; Q. petraea [Matt] Liebl.) often coexist in mixed forest stands. However, species-specific investigations and forest management actions in such populations require reliable methods of identification of the species status of individuals. We investigated genetic diversity and species differentiation of adult and naturally established seedling cohorts in a mixed forest stand composed of Q. robur and Q. petraea, located in the Jamy Nature Reserve in north-central Poland. Using nineteen nuclear microsatellite loci and a model-based clustering approach as a tool for species delineation, we efficiently identified 105 and 60 adults, as well as 191 and 456 seedlings of pedunculate and sessile oaks, respectively. While the adult trees of both species were randomly distributed throughout the sample plot, the seedlings demonstrated significant spatial clustering, which was particularly evident for Q. petraea. The two oak species exhibited similar levels of genetic diversity in adult and offspring cohorts. Inbreeding was found to be low and significant only at the stage of seedlings. The estimates of effective population size were higher for Q. robur than Q. petraea, despite the overall greater reproductive success of the later one. There was a significant level of differentiation between the studied oak species, as measured by Fst coefficient (0.084 – adults; 0.099 – seedlings). The results on genetic diversity and species differentiation obtained in the studied indigenous near-natural stand of Q. robur and Q. petraea could be considered as a reference for other population genetic studies of oaks.
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Abstract

In the complex RLC network, apart from the currents flows arising from the normal laws of Kirchhoff, other distributions of current, resulting from certain optimization criteria, may also be received. This paper is the development of research on distribution that meets the condition of the minimum energy losses within the network called energy-optimal distribution. Optimal distribution is not reachable itself, but in order to trigger it off, it is necessary to introduce the control system in current-dependent voltage sources vector, entered into a mesh set of a complex RLC network. For energy-optimal controlling, to obtain the control operator, the inversion of R(s) operator is required. It is the matrix operator and the dispersive operator (it depends on frequency). Inversion of such operators is inconvenient because it is algorithmically complicated. To avoid this the operator R(s) is replaced by the R’ operator which is a matrix, but non-dispersive one (it does not depend on s). This type of control is called the suboptimal control. Therefore, it is important to make appropriate selection of the R’ operator and hence the suboptimal control. This article shows how to implement such control through the use of matrix operators of multiple differentiation or integration. The key aspect is the distribution of a single rational function H(s) in a series of ‘s’ or ‘s⁻¹’. The paper presents a new way of developing a given, stable rational transmittance with real coefficients in power series of ‘s/s⁻¹՚. The formulas to determine values of series coefficients (with ‘s/s⁻¹’) have been shown and the conditions for convergence of differential/integral operators given as series of ‘s/s⁻¹’ have been defined.
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