1,245 research outputs found
Pengaruh Model Eliciting Activities Terhadap Kreativitas Matematis Pada Siswa Kelas VIII Pada Satu Sekolah Di Kab. Karawang
This study is focused to determine how much influence the learning of mathematics using the model eliciting activities for students of class VIII mathematical creativity. Experimental method used in this study, with a one-sample design group design. The population is all eighth grade students at a school in Karawang, with a sample of 30 students through random sampling with replacement technique. The results obtained by the model eliciting activities provide a strong enough influence on mathematical creativity, which amounted to 64%, other factors caused by moderate variable
Simulation of brittle damage for fracture process of endodontically treated tooth
The mechanics of brittle damage in porcelain of an endodontically treated maxilla incisor tooth was simulated using finite element method (FEM). For this purpose a very complex composite structure of endodontically treated tooth is simulated under transverse loading. Three dimensional (3D) model of human maxilla incisor tooth root was developed based on Computed Tomography (CT) scan images. Crown, core cement, resin core, dental post, post cement and dentin were created using SolidWorks software, and then the model was imported into ABAQUS-6.9EF software for nonlinear behavior analysis. This study utilizes finite element method to simulate onset and propagation of crack in ceramic layer (porcelain) by the cause of both tension and compression loading related to complexity of the geometry of tooth implant. The simulation has been done using brittle damaged model available in ABAQUS/Explicit in quasi-static load condition. The load-displacement response of whole structure is measured from the top of porcelain by controlling displacement on a rigid rod. Crack initiated at the top of porcelain bellow the location of the rod caused by tension damage at equivalent load of 590 N. Damage in porcelain accounts for up to 63% reduction of whole structure stiffness from the undamaged state. The failure process in porcelain layer can be described by an exponential rate of fracture energy dissipation. This study demonstrated that the proposed finite element model and analysis procedure can be use to predict the nonlinear behavior of tooth implant
Nicholas Reactions in the Construction of Cyclohepta[de]naphthalenes and Cyclohepta[de]naphthalenones. The Total Synthesis of Microstegiol
The application of the Nicholas reaction chemistry of 2,7-dioxygenated naphthalenes in the synthesis of cyclohepta[de]napthalenes and in the synthesis of (±)-microstegiol (1) is presented. The substitution profile of Nicholas monosubstitution (predominantly C-1) and disubstitution reactions (predominantly 1,6-) on 2,7-dioxygenated napthalenes is reported. Application of a 1,8-dicondensation product and selected C-1 monocondensation products to the construction of cyclohepta[de]naphthalenes by way of ring closing metathesis and intramolecular Friedel−Crafts reactions, respectively, is described. Deprotection of the C-7 oxygen function to the corresponding naphthol allows tautomerization to cyclohepta[de]naphthalene-1-ones upon seven-membered-ring closure in most cases, and replacement of the C-2 oxygen function in the naphthalene by a methyl group ultimately allows the synthesis of (±)-microstegiol
Cyclohepta[de]naphthalenes and the Rearranged Abietane Framework of Microstegiol via Nicholas Reaction Chemistry
Nicholas reactions on 2,7-dioxygenated naphthalenes give C-1 monosubstitution and C-1/C-8 disubstitution in most cases. From gamma-carbonyl cation monocondensation product 3b or alkyne-unsubstituted dicondensation product 4a, cyclohepta[de]naphthalenes bearing no substituents, gem-dimethyl substituents, and a ketone function, and the rearranged abietane framework of microstegiol may be prepared
RefreshNet: Learning Multiscale Dynamics through Hierarchical Refreshing
Forecasting complex system dynamics, particularly for long-term predictions,
is persistently hindered by error accumulation and computational burdens. This
study presents RefreshNet, a multiscale framework developed to overcome these
challenges, delivering an unprecedented balance between computational
efficiency and predictive accuracy. RefreshNet incorporates convolutional
autoencoders to identify a reduced order latent space capturing essential
features of the dynamics, and strategically employs multiple recurrent neural
network (RNN) blocks operating at varying temporal resolutions within the
latent space, thus allowing the capture of latent dynamics at multiple temporal
scales. The unique "refreshing" mechanism in RefreshNet allows coarser blocks
to reset inputs of finer blocks, effectively controlling and alleviating error
accumulation. This design demonstrates superiority over existing techniques
regarding computational efficiency and predictive accuracy, especially in
long-term forecasting. The framework is validated using three benchmark
applications: the FitzHugh-Nagumo system, the Reaction-Diffusion equation, and
Kuramoto-Sivashinsky dynamics. RefreshNet significantly outperforms
state-of-the-art methods in long-term forecasting accuracy and speed, marking a
significant advancement in modeling complex systems and opening new avenues in
understanding and predicting their behavior
Nutritional Evaluation and Physicochemical Properties of Fermented Shirezh Dairy Product
Many of the Kurdish traditional dairy products have not been studied thoroughly so far though are still produced at small scale. Dow (sour butter milk) and Shirezh are among these products. Shirezh known to Iraqi Kurds as sour concentrated Dow. The characteristics of Shirezh and Dow were: pH (5.5, 4.05), acidity (2.13%, 1.10%), total solids (18.70%, 5.32%), ash (0.62%, 0.45%), fat (2.57%, 0.8%) and total protein (13.59%, 3.28%) respectively, furthermore the amino acids of Shirezh’s protein found in balanced and acceptable quality. The aim of this research is to introduce Shirezh and Dow to scientific literature and to determine their characterization and nutritional values. Keywords: Shirezh, Dow, Dairy, Fermented, Nutrition, Physicochemical, Amino acids
Does the institutional quality matter for renewable energy promotion in the OECD economies?
This study examines the effect of institutional quality on renewable energy promotion in the OECD economies. The study employs annual data from 1980 to 2014 on 18 OECD economies. The robust panel unit root tests show that all the considered variables have a similar order of integration, indicating that they are nonstationary at their levels but stationary at the first-order differences. The panel cointegration test with structural breaks and cross-section dependence confirms a long-run equilibrium association between institutional quality, renewable energy consumption, and control variables. The analysis of long-run estimations displays that better institutional quality makes a unique and substantial contribution to promoting renewable energy consumption. Overall, the study findings offer important policy implications highlighting the importance of institutional quality for the growth of renewable energy and a sustainable world
Hypoalbuminaemia predicts outcome in adult patients with congenital heart disease
Background In patients with acquired heart failure, hypoalbuminaemia is associated with increased risk of death. The prevalence of hypoproteinaemia and hypoalbuminaemia and their relation to outcome in adult patients with congenital heart disease (ACHD) remains, however, unknown. Methods Data on patients with ACHD who underwent blood testing in our centre within the last 14 years were collected. The relation between laboratory, clinical or demographic parameters at baseline and mortality was assessed using Cox proportional hazards regression analysis. Results A total of 2886 patients with ACHD were included. Mean age was 33.3 years (23.6–44.7) and 50.1% patients were men. Median plasma albumin concentration was 41.0 g/L (38.0–44.0), whereas hypoalbuminaemia (<35 g/L) was present in 13.9% of patients. The prevalence of hypoalbuminaemia was significantly higher in patients with great complexity ACHD (18.2%) compared with patients with moderate (11.3%) or simple ACHD lesions (12.1%, p<0.001). During a median follow-up of 5.7 years (3.3–9.6), 327 (11.3%) patients died. On univariable Cox regression analysis, hypoalbuminaemia was a strong predictor of outcome (HR 3.37, 95% CI 2.67 to 4.25, p<0.0001). On multivariable Cox regression, after adjusting for age, sodium and creatinine concentration, liver dysfunction, functional class and disease complexity, hypoalbuminaemia remained a significant predictor of death. Conclusions Hypoalbuminaemia is common in patients with ACHD and is associated with a threefold increased risk of risk of death. Hypoalbuminaemia, therefore, should be included in risk-stratification algorithms as it may assist management decisions and timing of interventions in the growing ACHD population
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