73 research outputs found

    Identification of a hermit crab, Clibanarius signatus, in Hormuz Island: abundance, sex ratio and shell selection behaviors

    Get PDF
    In order to establish a complete list of the hermit crab species in the southern coast of Iran and also determine some of their biological characteristics in the intertidal zones of Hormuz Island, a seasonal sampling collection was conducted in 6 intertidal stations during the years 2010–2011. The 542 collected samples were found to be Clibanarius signatus, which identified in the island. Comparing the samples with the metatypical hermit crab samples in the Zoological Museum, University of Tehran, verified the species. The one ways ANOVA with LSD test showed a significant difference (p < 0.05) in the abundance of the species in some stations, but seasonal changes did not significantly affect the abundance. Male-female sex ratio was 1/52 male: 1 female. Seasonal study of sexes (male, non-ovigerous female, ovigerous female) confirmed that species did not have a particular spawning season, nevertheless the spawning increased in summer. The shell selection behaviors showed that the hermit crab uses the shells of 36 gastropod species (24 genera) for protecting its abdominal section

    The Ground State of Graphene and Graphene Disordered by Vacancies

    Full text link
    Graphene clusters consisting of 24 to 150 carbon atoms and hydrogen termination at the zigzag boundary edges have been studied, as well as clusters disordered by vacancy(s). Density Function Theory and Gaussian03 software were used to calculate graphene relative stability, desorption energy, band gap, density of states, surface shape, dipole momentum and electrical polarization of all clusters by applying the hybrid exchange-correlation functional Beke-Lee-Yang-Parr. Furthermore, infrared frequencies were calculated for two of them. Different basis sets, 6-31g**, 6-31g* and 6-31g, depending on the sizes of clusters are considered to compromise the effect of this selection on the calculated results. We found that relative stability and the gap decreases according to the size increase of the graphene cluster. Mulliken charge variation increase with the size. For about 500 carbon atoms, a zero HOMO-LUMO gap amount is predicted. Vacancy generally reduces the stability and having vacancy affects the stability differently according to the location of vacancies. Surface geometry of each cluster depends on the number of vacancies and their locations. The energy gap changes as with the location of vacancies in each cluster. The dipole momentum is dependent on the location of vacancies with respect to one another. The carbon-carbon length changes according to each covalence band distance from the boundary and vacancies. Two basis sets, 6-31g* and 6-31g**, predict equal amount for energy, gap and surface structure, but charge distribution results are completely different.Comment: 21 pages, 14 figures, 2 table

    Livro didático público paranaense "lingua portuguesa e literatura" : o professor-autor e o gênero discursivo

    Get PDF
    Orientadora: Profa. Dra. Iara Bemquerer CostaAutor não autorizou a divulgação do arquivo digitalTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Humanas, Letras e Artes, Programa de Pós-Graduação em Letras. Defesa: Curitiba, 23/04/2012Bibliografia: fls. 163-178Área de concentração :Resumo: Esta pesquisa descritivo-explicativa tem como objetivo averiguar a relacao dialogica entre o Livro Didatico Publico Paranaense \Lingua Portuguesa e Literatura. (LDP-PR) e os livros representantes do genero discursivo Livro Didatico de Lingua Portuguesa (LD-LP). A partir de uma perspectiva socio-historico-discursiva e empregando fontes bibliografica e documental, desenvolvemos esta pesquisa em duas etapas. Na primeira, procuramos efetuar uma reflexao teorica sobre os Generos Discursivos (BAKHTIN) e sobre como a abordagem sociointeracionista se apropria desta concepcao bakhtiniana e discute a questao da didatizacao dos generos (SCHNEUWLY e DOLZ). Na segunda, aplicamos estes pressupostos ao LDP-PR com o intuito de averiguar o encaminhamento didatico dado aos textos de generos discursivos empregados neste material didatico. A partir desta averiguacao do conteudo tematico do LDP-PR, realizada pelo trabalho com as praticas de leitura, escrita e oralidade, buscamos sustentacao para a analise deste LD como um exemplar do genero LD-LP. Nossos resultados mostram que o LDP-PR inova na escolha do conteudo tematico, mas mantem o estilo (marcado pelo emprego de discursos injuntivos, explicativos e expositivos) e a construcao composicional (de textualidade multimodal) tipicos do genero LD-LP. Creditamos a autoria multipla (constituida por professores da rede escolar), marcada pela experiencia reduzida e a merce da Secretaria de Estado da Educacao do Parana (SEED-PR) este apego ao genero consolidado.Abstract: This descriptive-explanatory research aims to investigate the dialogic relationship between the Parana‘s Public Textbook "Portuguese and Literature" (LDP-PR) and the representative books of the discursive genre of Portuguese Textbook (LP-LD). From a socio-historic-discursive perspective and by the use of bibliographical and documentary sources, we developed this research in two stages. In the first one, we carried out a theoretical reflection about the Discursive Genres (BAKHTIN) and how the social interactionist approach appropriates this Bakhtinian concept and discusses the issue of making genre educational (SCHNEUWLY and DOLZ). In the second one, we applied these assumptions to the LDP-PR with the intent of investigating the educational directions given to the texts of discursive genres employed in such a teaching materials. From this investigation of the LDP-PR‘s thematic contents, performed through the work with reading, writing and speaking skills practices, we sought support for the analysis of this LD as an exemplar of the LD-LP genre. Our results reveal that the LDP-PR innovates the choice of the thematic content but retains the style (marked by the use of injunctive, explanatory and expository discourses) and compositional construction (multimodal textuality) that is typical of the LD-LP genre. We attribute to the multiple authorship (made up of teachers from the public educational system), marked by limited experience and at the mercy of the Parana‘s State Department of Education (SEED-PR), this attachment to the consolidated genre

    A global experience‐sampling method study of well‐being during times of crisis: The CoCo project

    Get PDF
    We present a global experience-sampling method (ESM) study aimed at describing, predicting, and understanding individual differences in well-being during times of crisis such as the COVID-19 pandemic. This international ESM study is a collaborative effort of over 60 interdisciplinary researchers from around the world in the “Coping with Corona” (CoCo) project. The study comprises trait-, state-, and daily-level data of 7490 participants from over 20 countries (total ESM measurements = 207,263; total daily measurements = 73,295) collected between October 2021 and August 2022. We provide a brief overview of the theoretical background and aims of the study, present the applied methods (including a description of the study design, data collection procedures, data cleaning, and final sample), and discuss exemplary research questions to which these data can be applied. We end by inviting collaborations on the CoCo dataset

    Numerical and experimental investigations of diffusion absorption refrigeration systems for use with low temperature heat sources

    No full text
    he diffusion absorption refrigeration (DAR) cycle is a technology of increasing interest thanks to its suitab ility for providing cooling from a thermal energy input in a range of applications . It can be distinguished from other absorption refrigeration cycles by its employment of a thermally - driven bubble pump to circulate the working fluid , which gives it an ability to operate entirely off - grid without an electricity input . In this work , we present results from an experimental campaign aimed at characteri s ing the performance of a prototype ammonia - water - hydrogen D AR system with a nominal cooling capacity of 100 W, over a range of operating conditions, specifically with a view of adapt ing the system for use in low - temperature applications. In the experiments, the heat input to the DAR generator is provided over a ra ng e of temperatures from 175 to 215 °C by using electrical cartridge heaters. The system is charged to 22 bar, and the ammonia mass concentration of the working fluid mixture is 30%. The resulting coefficient of performance (COP) of the system is measured in the range 0.12 to 0.26 . A new methodology for the selection of optimal working - fluid mixtures using the state - of - the - art, statistical associating fluid theory (SAFT) approach implemented within the process modelling software gPROMS ® is also presented. The experimental results will be used for future validation of a thermodynamic model of the cycle. Finally, the performance of the system in a solar application is investigated, with a thermal input provided by an array of evacuated tube heat pipe solar collectors. The system pressure and condensation temperature are found to be key factors in determining the performance of solar - DAR system s

    Preparation of decellularized three dimentional scaffolds as the model for tissue engineering and their functional assessments in vitro application of blastema tissue

    No full text
    Tissue engineering is based on three main factors including scaffolds, cells and growth factors. Natural scaffolds derived from decellularized tissues and organs have been successfully used in tissue engineering. Decellularization studies have shown that natural scaffolds which maintaine their main structure and properties could be a suitable tool for studying cellular behaviors and preparation of such scaffolds is an important part of future research in biology that may have extensive applications in regenerative medicine and tissue engineering. Blastema tissue which is produced after injuries in some organisms has embryonic cell characteristics, and can be a suitable model for evaluation of cell behaviors in various tissues. In this review, the process of decellularization, process involved in preparation of 3D scaffolds derived from extracellular matrix of various tissues including cartilage, bone, gingiva, aorta and bladder, and assessment of their interactions with blastema tissue under in vitro conditions are discussed.   Keywords: Tissue engineering, Blastema tissue, Regenerative.
    corecore