135 research outputs found
Identification of a hermit crab, Clibanarius signatus, in Hormuz Island: abundance, sex ratio and shell selection behaviors
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 2010â2011. 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
Experimental investigation of an ammonia-water-hydrogen diffusion absorption refrigerator
Diffusion absorption refrigeration (DAR) is a small-scale cooling technology that can be driven purely by thermal energy without the need for electrical or mechanical inputs. In this work, a detailed experimental evaluation was undertaken of a newly-proposed DAR unit with a nominal cooling capacity of 100~W, aimed at solar-driven cooling applications in warm climates. Electrical cartridge heaters were used to provide the thermal input which was varied in the range 150-700 W, resulting in heat source temperatures of 175--215 C measured at the generator. The cooling output during steady-state operation was determined from the power consumed by an electric heater used to maintain constant air temperature in an insulated box constructed around the evaporator. Tests were performed with the DAR system configured with the default manufacturer's settings (22 bar charge pressure and 30 % ammonia concentration). The measured cooling output (to air) across the range of generator heat inputs was 24--108 W, while the coefficient of performance (COP) range was 0.11--0.26. The maximum COP was obtained at a generator heat input of 300 W. Results were compared to performance predictions from a steady-state thermodynamic model of the DAR cycle, showing a reasonable level of agreement at the nominal design point of system, but noteworthy deviations at part-load/off-design conditions. Temperature measurements from the experimental apparatus were used to evaluate assumptions used in the estimation of the model state point parameters and examine their influence on the predicted system performance
Investigation the Relationship among Mobile Value-added Services Quality, Customer Satisfaction and the Continuance Intention: Case Study, Hamrah Avval Operator
Understanding the antecedents and consequences of customer satisfaction in the mobile communications market is important. This study explores the effects of service quality, trust and perceived value on customer satisfaction, which, in turn, affects continuance intention of mobile services. Service quality and customer satisfaction were measured by multiple dimensions. A research model was developed based on this multidimensional approach and was empirically examined with data collected from about one 237 users of mobile value-added services in Tehran university. Results show that all two dimensions of service quality (interaction quality and outcome quality) and perceived value have significant and positive effects on customer satisfaction while only one dimension of service quality (environment quality) and trust have no effect on customer satisfaction
Integrated modeling and validation for phase change with natural convection
Water-ice systems undergoing melting develop complex spatio-temporal
interface dynamics and a non-trivial temperature field. In this contribution,
we present computational aspects of a recently conducted validation study that
aims at investigating the role of natural convection for cryo-interface
dynamics of water-ice. We will present a fixed grid model known as the enthalpy
porosity method. It is based on introducing a phase field and employs mixture
theory. The resulting PDEs are solved using a finite volume discretization. The
second part is devoted to experiments that have been conducted for model
validation. The evolving water-ice interface is tracked based on optical images
that shows both the water and the ice phase. To segment the phases, we use a
binary Mumford Shah method, which yields a piece-wise constant approximation of
the imaging data. Its jump set is the reconstruction of the measured phase
interface. Our combined simulation and segmentation effort finally enables us
to compare the modeled and measured phase interfaces continuously. We conclude
with a discussion of our findings
The Ground State of Graphene and Graphene Disordered by Vacancies
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
Demonstration of the histopathological and immunohistochemical effects of a novel hemostatic agent, ankaferd blood stopper, on vascular tissue in a rat aortic bleeding model
Background: Ankaferd Blood StopperŸ(ABS) is a folkloric medicinal plant extract used as a hemostatic agent in traditional Turkish medicine. This experimental study investigated the histopathological and immunohistochemical effects of ABS on vascular tissue in a rat model of aortic bleeding.Methods: Four groups of 11 Wistar albino rats were used. The abdominal aortas of the rats were wounded; an ABS-soaked tampon was applied to rats in Groups 1 and 3, and a plain gauze tampon was applied to rats in Groups 2 and 4 until the bleeding stopped. The bleeding time was recorded. Immediately following sacrificing, the arteriotomy sites from Groups 1 and 2 were removed. The abdominal incisions in Groups 3 and 4 were closed following hemostasis. On Day 7 of the study, Group 3 and 4 rats were sacrificed and the abdominal aorta arteriotomy sites were removed for histopathological and immunohistochemical evaluation.Results: The mean bleeding time in 15 animals in Groups 2 and 4 was 4.9 ± 0.6 s, and in 22 animals in Groups 1 and 3 was 3.1 ± 0.6 s. Distal aortic occlusion was not observed on either Day 1 or 7 in any group. Significantly more widespread and dense endothelial nitric oxide synthase (eNOS) staining was observed in Group 1 animals than Group 2. On Days 1 and 7 after application of ABS, histopathological changes, consisting of necrosis, inflammation, and endothelial cell loss, in the rat abdominal aortas did not differ between Groups 1 and 2. The basophilic discoloration in the ABS group on the operation day was a result of a foreign body reaction and hemosiderin-loaded histiocyte accumulation, which occurred on Day 7.Conclusions: In this study, hemostasis was successfully achieved with ABS in rat abdominal aortas. No histopathological change was found in the rat abdominal aortas between the ABS and control groups on Days 1 and 7. Further studies on the long-term effects of foreign body reactions and hemosiderin-loaded histiocyte accumulation are required. © 2010 Kandemir et al; licensee BioMed Central Ltd
Livro didĂĄtico pĂșblico paranaense "lingua portuguesa e literatura" : o professor-autor e o gĂȘnero discursivo
Orientadora: Profa. Dra. Iara Bemquerer CostaAutor nĂŁo autorizou a divulgação do arquivo digitalTese (doutorado) - Universidade Federal do ParanĂĄ, Setor de CiĂȘncias Humanas, Letras e Artes, Programa de PĂłs-Graduação em Letras. Defesa: Curitiba, 23/04/2012Bibliografia: fls. 163-178Ărea 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 Paranaâs 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-PRâs 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 Paranaâs State Department of Education (SEED-PR), this attachment to the consolidated genre
A global experienceâsampling method study of wellâbeing during times of crisis: The CoCo project
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 âCoping with Coronaâ (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
A hybrid simulator model for the control of catastrophic external junctional haemorrhage in the military environment
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