31 research outputs found
Quantifying origin and character of long-range correlations in narrative texts
In natural language using short sentences is considered efficient for
communication. However, a text composed exclusively of such sentences looks
technical and reads boring. A text composed of long ones, on the other hand,
demands significantly more effort for comprehension. Studying characteristics
of the sentence length variability (SLV) in a large corpus of world-famous
literary texts shows that an appealing and aesthetic optimum appears somewhere
in between and involves selfsimilar, cascade-like alternation of various
lengths sentences. A related quantitative observation is that the power spectra
S(f) of thus characterized SLV universally develop a convincing `1/f^beta'
scaling with the average exponent beta =~ 1/2, close to what has been
identified before in musical compositions or in the brain waves. An
overwhelming majority of the studied texts simply obeys such fractal attributes
but especially spectacular in this respect are hypertext-like, "stream of
consciousness" novels. In addition, they appear to develop structures
characteristic of irreducibly interwoven sets of fractals called multifractals.
Scaling of S(f) in the present context implies existence of the long-range
correlations in texts and appearance of multifractality indicates that they
carry even a nonlinear component. A distinct role of the full stops in inducing
the long-range correlations in texts is evidenced by the fact that the above
quantitative characteristics on the long-range correlations manifest themselves
in variation of the full stops recurrence times along texts, thus in SLV, but
to a much lesser degree in the recurrence times of the most frequent words. In
this latter case the nonlinear correlations, thus multifractality, disappear
even completely for all the texts considered. Treated as one extra word, the
full stops at the same time appear to obey the Zipfian rank-frequency
distribution, however.Comment: 28 pages, 8 figures, accepted for publication in Information Science
Comparison of the yeast microbiota of different varieties of cool-climate grapes by PCR-RAPD
The yeast microbiota occurring on different varieties of grapes grown in cool-climate is not completely researched. Therefore, its identification is important to research. On the other hand, yeasts occurring in these fruits can be potentially used as starter cultures to obtain particularly demanded features in the production of wine. In addition, rapid methods for yeast identification allow to eliminate the contamination with pathogenic yeasts, which could cause the loss of wine production. The aim of the study was to isolate and identify the yeasts occurring on the surface of the different varieties of white and red grapes, grown in cool-climate of Poland. Also, the aim was to compare the qualitative and quantitative composition of yeasts on the tested grapes. The 84 cultures of yeasts were isolated, that were initially macroscopic and microscopic analyzed and the purity of cultures was rated on the WL medium. Identification of yeasts by PCR-RAPD was carried using the M13 primer. In the PCR-RFLP method ITS1 and ITS4 primers, as well as restriction enzymes HhaI, HinfI, HaeIII, were used. Preliminary identification of yeasts by standard methods produced results very different from the results obtained by molecular methods. Among the isolated microorganisms yeasts were dominating, but bacteria and molds were also present. Using the PCR-RAPD method most strains of yeasts were identified. Yeast microflora of different varieties of white and red grapes was very similar as the same species of yeasts were identified. Yeasts of the genus Saccharomyces were present in all varieties of grapes. The Rhodotorula mucilaginosa, Saccharomyces cerevisiae, Metschnikowia pulcherrima, Rhodotorula minuta, Pichia kluyveri, Hanseniaspora uvarum and Rhodotorula mucilaginosa were identified by PCR-RAPD. 4 of the 33 tested strains of yeasts were identified by PCR-RFLP. By PCR-RAPD only Hanseniaspora uvarum was identified. The quantity and quality of microorganisms living on the surface of grape fruits is very important for the process of winemaking. Yeasts influence the course of alcoholic fermentation, the flavor, aroma, and thus the quality of the produced wine. To a large extent their presence depends on the condition of the surface of the fruit. Many researchers reported significant differences between yeast microflora in grapes of Mediterranean and cool-climate vineyards. As they are expected to affect the final wine properties precise researching of the microflora of cool-climate grapes may lead to the isolation of new species of yeasts and thus the wines with unique characteristics can be obtained
Complex network analysis of literary and scientific texts
We present results from our quantitative study of statistical and network
properties of literary and scientific texts written in two languages: English
and Polish. We show that Polish texts are described by the Zipf law with the
scaling exponent smaller than the one for the English language. We also show
that the scientific texts are typically characterized by the rank-frequency
plots with relatively short range of power-law behavior as compared to the
literary texts. We then transform the texts into their word-adjacency network
representations and find another difference between the languages. For the
majority of the literary texts in both languages, the corresponding networks
revealed the scale-free structure, while this was not always the case for the
scientific texts. However, all the network representations of texts were
hierarchical. We do not observe any qualitative and quantitative difference
between the languages. However, if we look at other network statistics like the
clustering coefficient and the average shortest path length, the English texts
occur to possess more clustered structure than do the Polish ones. This result
was attributed to differences in grammar of both languages, which was also
indicated in the Zipf plots. All the texts, however, show network structure
that differs from any of the Watts-Strogatz, the Barabasi-Albert, and the
Erdos-Renyi architectures
Synergistic ROS-Associated antimicrobial activity of silver nanoparticles and gentamicin against "Staphylococcus epidermidis"
Introduction: Increasing bacteria resistance to antibiotics is a major problem of healthcare
system. There is a need for solutions that broaden the spectrum of bactericidal agents
improving the efficacy of commonly used antibiotics. One of the promising directions of
search are silver nanoparticles (obtained by different methods and displaying diversified
physical and chemical properties), and their combination with antibiotics.
Purpose: In this study, we tested the role of reactive oxygen species in the mechanism of
synergistic antibacterial activity of gentamicin and Tween-stabilized silver nanoparticles
against gentamicin-resistant clinical strains of Staphylococcus epidermidis.
Methods: Synergistic bactericidal activity of gentamicin and silver nanoparticles stabilized with
non-ionic detergent (Tween 80) was tested by the checkerboard titration method on microtiter
plates. Detection of reactive oxygen species was based on the chemiluminescence of luminol.
Results: Hydrophilic non-ionic surface functionalization of silver nanoparticles enabled the
existence of non-aggregated active nanoparticles in a complex bacterial culture medium.
Tween-stabilized silver nanoparticles in combination with gentamicin exhibited bactericidal
activity against multidrug-resistant biofilm forming clinical strains of Staphylococcus epidermidis. A synergistic effect significantly decreased the minimal inhibitory concentration of
gentamicin (the antibiotic with numerous undesirable effects). Gentamicin significantly
enhanced the generation of reactive oxygen species by silver nanoparticles.
Conclusion: Generation of reactive oxygen species by Tween-coated metallic silver nanoparticles was significantly enhanced by gentamicin, confirming the hypothesis of oxidative-associated
mechanism of the synergistic antibacterial effect of the gentamicin-silver nanoparticles complex
Czynniki ryzyka rozwoju migotania przedsionków, nie zawsze ciężkiej i nie zawsze izolowanej choroby serca
Dotychczas nie poznano dokładnych mechanizmów wpływających na powstanie migotania
przedsionków (AF). Każdorazowo klinicysta musi sobie odpowiedzieć na pytanie, czy ma do
czynienia z izolowanym AF czy wywołanym innymi zamaskowanymi zaburzeniami. Migotanie
przedsionków ma bowiem silne związki epidemiologiczne z innymi chorobami sercowo-naczyniowymi, takimi jak niewydolność serca, choroba wieńcowa, wady zastawkowe, cukrzyca
czy nadciśnienie tętnicze. W pracy omówiono tak zwane nowe czynniki ryzyka i mechanizmy,
w wyniku których prowadzą one do powstania migotania przedsionków. Na podstawie najnowszych
badań zaprezentowano obecny stan wiedzy o związku występowania AF z następującymi
zaburzeniami: zespołem metabolicznym i jego składowymi, bezdechem sennym oraz procesem
zapalnym. Opisano również niektóre aspekty wpływu stylu życia (spożycie alkoholu
i aktywność fizyczna) na pojawianie się epizodów migotania przedsionków. (Folia Cardiologica
Excerpta 2010; 5, 5: 285-291
Zagrożenia zdrowotne wśród dzieci i młodzieży. T. 1
Praca recenzowana / Peer-reviewed pape