203 research outputs found
A Formal Treatment of Generalized Preferential Attachment and its Empirical Validation
Generalized preferential attachment is defined as the tendency of a vertex to
acquire new links in the future with respect to a particular vertex property.
Understanding which properties influence link acquisition tendency (LAT) gives
us a predictive power to estimate the future growth of network and insight
about the actual dynamics governing the complex networks. In this study, we
explore the effect of age and degree on LAT by analyzing data collected from a
new complex-network growth dataset. We found that LAT and degree of a vertex
are linearly correlated in accordance with previous studies. Interestingly, the
relation between LAT and age of a vertex is found to be in conflict with the
known models of network growth. We identified three different periods in the
network's lifetime where the relation between age and LAT is strongly positive,
almost stationary and negative correspondingly
Developing a “values teaching responsibility perception scale” for prospective teachers
In this study a measurement device that could be used to determine the values teaching responsibility perceptions of prospective teachers was aimed to be developed. For this purpose, literature on values teaching was investigated and the views of prospective teachers were taken and a 46 itemed item pool was prepared. The items were reorganized according to expert views and 46 item preliminary form was prepared. This preliminary form was applied to 274 prospective teachers 206 of whom were female and 62 were male studying in different grades and departments of Gazi University Gazi Faculty of Education in 2018-2019 academic year Autumn semester. Validity and reliability analyses were conducted on the data set obtained from the application. The data set was applied first Exploratory Factor Analysis (EFA) for construct validity and then Confirmatory Factor Analysis (CFA). Confirmatory Factor Analysis (CFA) was applied on a different group of 352 prospective teachers 278 of whom were female and 80 male. At the end of exploratory factor analysis, a scale form consisting of 35 items and 4 sub-dimensions was obtained. The four factor structure about the scale explains the 61.46% of the total variance. According to the reliability analysis Cronbach alpha reliability coefficient for the overall scale is .97, for sub-dimensions respectively as .93, .93, .88 and .84. The model fit indices for the scale at the end of the confirmatory factor analysis are determined as RMSEA, .064; χ2/df=2.1; SRMR=.06; IFI=.90; CFI=.90. Values obtained from this shows that the scale construct is validated
FRESH CONCRETE PROPERTIES AND COMPRESSIVE STRENGTH OF SELF COMPACTING CONCRETES WITH SILICA FUME AND FLY ASH
Kendiliğinden yerleşen betonlar (KYB), geleneksel betona oranla işlenebilirlik, işçilik maliyetindeki azalmalar ve yüksek dayanım gibi önemli faydalar sağlayan beton teknolojisindeki gelişmelerdendir. KYB üretiminde yüksek oranda su azaltıcı süperakışkanlaştırıcı kimyasal katkılar, fazla miktarda toz malzeme ve/veya viskozite düzenleyici katkı maddesi kullanılmalıdır. Kendiliğinden yerleşme yeteneği; doldurma yeteneği, ayrışmaya karşı direnç ve geçiş yeteneği olmak üzere 3 parametre ile karakterize edilebilir. KYB üretiminde toz malzeme olarak genellikle kireçtaşı tozu, uçucu kül, granüle yüksek fırın cürufu ve silis dumanı kullanılmaktadır. Bu çalışmada mineral katkı maddesi olarak çimento yerine ağırlıkça % 5, % 10 ve % 15 oranlarında silis dumanı ve % 25, % 40 ve % 55 oranlarında uçucu kül kullanılarak KYB üretilmiş ve taze beton özellikleri ile sertleşmiş betonların 3, 7 ve 28 günlük basınç dayanımları belirlenmiştir. silis dumanı ilavesi basınç dayanımlarında artışa yol açarken uçucu kül katkılı betonlarda dayanım azalmaları tespit edilmiştir. En yüksek basınç dayanımı değeri 88 MPa değeri ile %15 silis dumanı kullanılarak üretilen betonlardan elde edilmiştir.Self Compacting Concrete, is one of the developments in concrete technology, which have important benefitsas workability, labor cost reductions and high-strength, compared to traditional concrete. In SCC production, high-range water reducing super plasticizer chemical additives, powder material and/or viscosity regulators additive must be used. Self-settlement capability may be characterized with 3 parameters; filling ability, resistance to decomposition and, passing ability between reinforcement bars. Limestone powder, fly ash, granulated blast furnace slag and silica fume is used as a powder material in SCC production. In this study SCC were produced with using silica fume instead of cement by weight, by the ratios of 5%, 10% and 15%, and fly ash with the ratios of 25%, 40% and 55%. Fresh concrete properties and 3, 7 and 28 days compressive strengths were determined. While SF increased compressive strength, addition of fly ash, on the contrary, decreased it. The highest compressive strength was observed from the concrete specimens with using 15% silica fume, with the value of 88 MPa. 
Overview of diagnosis and management of paediatric headache. Part I: diagnosis.
Headache is the most common somatic complaint in children and adolescents. The evaluation should include detailed history of children and adolescents completed by detailed general and neurological examinations. Moreover, the possible role of psychological factors, life events and excessively stressful lifestyle in influencing recurrent headache need to be checked. The choice of laboratory tests rests on the differential diagnosis suggested by the history, the character and temporal pattern of the headache, and the physical and neurological examinations. Subjects who have any signs or symptoms of focal/progressive neurological disturbances should be investigated by neuroimaging techniques. The electroencephalogram and other neurophysiological examinations are of limited value in the routine evaluation of headaches. In a primary headache disorder, headache itself is the illness and headache is not attributed to any other disorder (e.g. migraine, tension-type headache, cluster headache and other trigeminal autonomic cephalgias). In secondary headache disorders, headache is the symptom of identifiable structural, metabolic or other abnormality. Red flags include the first or worst headache ever in the life, recent headache onset, increasing severity or frequency, occipital location, awakening from sleep because of headache, headache occurring exclusively in the morning associated with severe vomiting and headache associated with straining. Thus, the differential diagnosis between primary and secondary headaches rests mainly on clinical criteria. A thorough evaluation of headache in children and adolescents is necessary to make the correct diagnosis and initiate treatment, bearing in mind that children with headache are more likely to experience psychosocial adversity and to grow up with an excess of both headache and other physical and psychiatric symptoms and this creates an important healthcare problem for their future life
Winds observed in the Northern European seas with wind lidars, meteorological masts and satellite
The Importance Of Schools’ Sport Promotion In Society,
This study aims to generalize of school sports in the society, and this indicates how it impresses
to the achievement of sporty.The universe of the research constitues physical education teachers
work at schools of Ministry of National Education. The sample of research constitutes is
composed twenty-six female and one hundred-two male physical education teachers, who work
in the center of Elazig. A questionnaire is applied as a data collection device, these rates and
frequency values of the questionnaire data are considered, and these values put into tables.
Consequently, physical education teachers participated in this research stated that; %85.1 (109
people) considers that school sports would be affective for spreading schools in society, %68 has
economic problems in sportive facilities, %95.3 thinks that hours of physical education courses
are not adequate, %83 considers that sports organizations among schools would be benefical for
national sports
Mechanisms of gut epithelial barrier impairment caused by food emulsifiers polysorbate 20 and polysorbate 80
Background
The rising prevalence of many chronic diseases related to gut barrier dysfunction coincides with the increased global usage of dietary emulsifiers in recent decades. We therefore investigated the effect of the frequently used food emulsifiers on cytotoxicity, barrier function, transcriptome alterations, and protein expression in gastrointestinal epithelial cells.
Methods
Human intestinal organoids originating from induced pluripotent stem cells, colon organoid organ‐on‐a‐chip, and liquid–liquid interface cells were cultured in the presence of two common emulsifiers: polysorbate 20 (P20) and polysorbate 80 (P80). The cytotoxicity, transepithelial electrical resistance (TEER), and paracellular‐flux were measured. Immunofluorescence staining of epithelial tight‐junctions (TJ), RNA‐seq transcriptome, and targeted proteomics were performed.
Results
Cells showed lysis in response to P20 and P80 exposure starting at a 0.1% (v/v) concentration across all models. Epithelial barrier disruption correlated with decreased TEER, increased paracellular‐flux and irregular TJ immunostaining. RNA‐seq and targeted proteomics analyses demonstrated upregulation of cell development, signaling, proliferation, apoptosis, inflammatory response, and response to stress at 0.05%, a concentration lower than direct cell toxicity. A proinflammatory response was characterized by the secretion of several cytokines and chemokines, interaction with their receptors, and PI3K‐Akt and MAPK signaling pathways. CXCL5, CXCL10, and VEGFA were upregulated in response to P20 and CXCL1, CXCL8 (IL‐8), CXCL10, LIF in response to P80.
Conclusions
The present study provides direct evidence on the detrimental effects of food emulsifiers P20 and P80 on intestinal epithelial integrity. The underlying mechanism of epithelial barrier disruption was cell death at concentrations between 1% and 0.1%. Even at concentrations lower than 0.1%, these polysorbates induced a proinflammatory response suggesting a detrimental effect on gastrointestinal health
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Effect of cobalt nanoparticles on mechanical properties of Sn–58Bi solder joint
Brittle phases are responsible for crack formation and propagation in tin–bismuth (Sn–58Bi) solder material. The purpose of this work is to investigate the effects of various cobalt (Co) nanoparticle (NP) concentrations on the tensile properties of the Sn–58Bi solder matrix. Different aging times were studied to find out the effect of Co NP on ultimate tensile strength. Tin–bismuth solder joints of different Co NP concentrations of 0%, 0.5%, 1%, and 2% were prepared. The reflow process was done at 180 °C for 1 min. Scanning Electron Microscopy and Energy-Dispersive X-ray spectroscopy were used to analyze the solder joints. The tensile test was carried out for the Sn–58Bi and Sn–58Bi–xCo (x = 0.5, 1, and 2) solder joints. The tensile test was run before and after aging time. The tensile results reveal that the addition of Co NP increased the tensile strength significantly at different concentrations of Co NP. The Tensile test revealed that ductility was improved as the temperature was increased. As the aging time increased, the ultimate tensile strength of all samples decreased
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