1,385 research outputs found

    Entropy of foliations with leafwise Finsler structure

    Full text link
    We extend the notion of the geometric entropy of foliation to foliated manifolds equipped with leafwise Finsler structure. We study the relation between the geometric entropy and the topological entropy of the holonomy pseudogroup. The case of foliated manifold with leafwise Randers structure. In this case the estimates for one dimensional foliation defined by a vector field in term of topological entropy of a flow are presented

    A small RNA response at DNA ends in Drosophila

    Get PDF
    Small RNAs have been implicated in numerous cellular processes, including effects on chromatin structure and the repression of transposons. We describe the generation of a small RNA response at DNA ends in Drosophila that is analogous to the recently reported double-strand break (DSB)-induced RNAs or Dicer- and Drosha-dependent small RNAs in Arabidopsis and vertebrates. Active transcription in the vicinity of the break amplifies this small RNA response, demonstrating that the normal messenger RNA contributes to the endogenous small interfering RNAs precursor. The double-stranded RNA precursor forms with an antisense transcript that initiates at the DNA break. Breaks are thus sites of transcription initiation, a novel aspect of the cellular DSB response. This response is specific to a double-strand break since nicked DNA structures do not trigger small RNA production. The small RNAs are generated independently of the exact end structure (blunt, 3â€Č- or 5â€Č-overhang), can repress homologous sequences in trans and may therefore—in addition to putative roles in repair—exert a quality control function by clearing potentially truncated messages from genes in the vicinity of the break

    Airborne magnetic technoparticles in soils as a record of Anthropocene

    Get PDF
    Airborne magnetic particles in soils were studied in sites located in various distances to industrial plants. Chemical and mineral composition of soil samples were analysed. The highest values of the Pollution Load Index (PLI) calculated for several elements were noted for sites relatively distant from industrial plants. Soil samples exposed for the deposition of airborne particles were examined by means of magnetization versus an external applied magnetic field as well as ^{52}Fe Mössbauer spectroscopy measurements showing a lack of correlation of the magnetic properties with total Fe content, which points toward a strong impact of the industrial activities. Magnetic fraction was extracted and studied using scanning electron microscopy with energy dispersive spectrometry. Two types of spherical particles were noted. Massive ones occurring in all sites and particles with a complex internal structure more abundant in sites situated closer to industrial plants. The presence of spherical magnetic particles formed in high temperature processes indicate their relatively long range transport in the atmosphere. Broad distribution, characteristic and easy for identification spherical form of these magnetic technoparticles, suggest that one can consider them as a record of the Anthropocene. Accumulation of such technoparticles is related to rapid industrialization in the post-World War II period

    Simulative Analysis of a New Type Wide Range Estimator of Protection Criterion Values

    Get PDF
    In the paper a new adaptive estimator of protection criterion values insensitive to wide range power system frequency changes is proposed and analysed. Its operation is based on a coarse calculation of signal frequency and appropriate correction of used orthogonal filters frequency responses as well as adaptation of chosen parameters of the measurement algorithm. The main features of the new method has been compared with standard criterion values estimators both theoretically and by simulations. The proposed estimators assure good accuracy of measurement within the frequency range from 5 to 95 Hz

    Comparison of Quality of Life Perceptions of Caregivers of Individuals With Intellectual Disabilities in the United States and the Czech Republic

    Get PDF
    Caregivers of individuals with disabilities in the United States have been reported to experience additional hardships than families with typical children as they attempt to balance family and work (Parish, Rose, Grinstein-Weiss, Richman, & Andrews, 2008). In this study, 31 caregivers of individuals with intellectual disabilities from the United States and 225 from the Czech Republic completed a qualitative quality of life survey. Similarities in the two groups were found in reported gains and losses from caregiving responsibilities. Differences in perceived spirituality, personal sense of peace and serenity, life optimism, ability to rejoice in life, personal life perspective, health, financial changes, changes in the family social life, feelings of enrichment, family caregiving responsibilities, and attitudes about the future were also revealed. The implications for supporting families through governmental programs and individualized services are discussed
    • 

    corecore