Three-Dimensional Hard Dumbbell Solid Free Energy Calculation Via the Fluctuating Cell Model

Determination of the solid–liquid phase transition point of a molecular substance requires calculation of the free energy in both phases. Progress has been made on this problem by modeling molecules as fused hard spheres and adding attraction and electric multipole moments perturbatively. The solid free energy of hard heteronuclear dumbbells of bond length L ^*, used to model diatomic molecules, can in principle be calculated exactly via the Frenkel–Ladd method, but this is computationally intensive. Use of Lennard Jones–Devonshire fixed cells to calculate free energy is much simpler computationally but is an approximation. The fluctuating cell model is investigated as an alternative intermediate method which is still computationally simpler than the Frenkel–Ladd method. As was found earlier in two dimensions, for small L ^* the simple cell model is in better agreement with Frenkel–Ladd than the fluctuating cell model, but for larger L ^* the fluctuating cell model is in better agreement. The probability distributions of free volumes are also analyzed and show different functional behavior for near-zero bond length and appreciable bond length.     

Investigating the relationships among instructional strategies and learning styles in online environments

This exploratory study tests the assertion that instructional strategies that match field-dependence status of students are most effective. The study conducted with 12 graduate students registered in a graduate level online course. An online version of the Psychological Differentiation Inventory was used to measure the field-dependence status of students. Students’ perceived learning outcomes, their effort and involvement, and level of interaction that they perceived in online course module were measured through an online questionnaire. Results suggested that matches between students’ learning styles and instructional strategies did not affect learner perception of their own learning outcomes, level of effort and involvement, and level of interactions in the course. Data also indicated that no single instructional strategy, among three instructional strategies tested, emerged as superior for high and low field-dependent online students.     

A bivariate fuzzy time series model to forecast the TAIEX

Fuzzy time series models have been applied to forecast various domain problems and have been shown to forecast better than other models. Neural networks have been very popular in modeling nonlinear data. In addition, the bivariate models are believed to outperform the univariate models. Hence, this study intends to apply neural networks to fuzzy time series forecasting and to propose bivariate models in order to improve forecasting. The stock index and its corresponding index futures are taken as the inputs to forecast the stock index for the next day. Both in-sample estimation and out-of-sample forecasting are conducted. The proposed models are then compared with univariate models as well as other bivariate models. The empirical results show that one of the proposed models outperforms the many other models.     

A geometric solution to the simultaneous bounded domain stabilization problem

This paper presents an algorithmic method for solving the two-plant simultaneous bounded domain stabilization problem for SISO LTI systems. This problem has no closed form solution. The solution provides robust performance in the presence of sensor or actuator failure, or other major parameter changes. Vidyasagar (1987) studied a similar problem involving partially bounded stability domains. However, stability with respect to partially bounded domains only partially bound performance characteristics, such as control energy and transient response. The current investigation gives necessary conditions for simultaneous bounded domain stability and demonstrates a geometry-based solution algorithm which can be automated. The possible solutions to the problem and the admissible solutions are represented as sets of points in Euclidean space. The solution to the problem is found by using computational geometric techniques to detect points in the intersection of these two sets, if there is one, and deducing the simultaneous stabilizing compensator design from the points found in the intersection.     

A Linear Approach for Experimental Dynamic Parameter Estimation of Planar Mechanisms

Because of joint constraints, not all standard dynamic parameters of amechanism affect its dynamic response. The set with the minimum numberof standard dynamic parameters or linear combinations of standarddynamic parameters that is sufficient to uniquely determine the dynamicresponse of the mechanism is defined as a set of base dynamicparameters. Accurate knowledge of base dynamic parameters is crucial foraccurate dynamic analysis. This paper presents a new experimental methodto estimate base dynamic parameters based on linearized dynamic modelsand frequency analysis techniques. Rather than using traditionaltrajectories, the system to be estimated is excited with a hammer forcecausing oscillation in several small neighborhoods that are optimized.It is locally treated as a linear system. Base dynamic parameters areextracted from the frequency response function (accelerance). It isshown that all base dynamic parameters of nonlinear systems can beestimated with this new method. This is a general method that can beused in the estimation of general mechanisms. The method is successfullytested on a computer simulated response of a planar four-bar mechanismin four optimal spring-loaded static equilibrium positions with 10 dB ofsuperimposed noise.     

Activation of Notch3 in Renal Tubular Cells Leads to Progressive Cystic Kidney Disease

Background: Polycystic kidney disease (PKD) is a genetic disorder affecting millions of people worldwide that is characterized by fluid-filled cysts and leads to end-stage renal disease (ESRD). The hallmarks of PKD are proliferation and dedifferentiation of tubular epithelial cells, cellular processes known to be regulated by Notch signaling. Methods: We found increased Notch3 expression in human PKD and renal cell carcinoma biopsies. To obtain insight into the underlying mechanisms and the functional consequences of this abnormal expression, we developed a transgenic mouse model with conditional overexpression of the intracellular Notch3 (ICN3) domain specifically in renal tubules. We evaluated the alterations in renal function (creatininemia, BUN) and structure (cysts, fibrosis, inflammation) and measured the expression of several genes involved in Notch signaling and the mechanisms of inflammation, proliferation, dedifferentiation, fibrosis, injury, apoptosis and regeneration. Results: After one month of ICN3 overexpression, kidneys were larger with tubules grossly enlarged in diameter, with cell hypertrophy and hyperplasia, exclusively in the outer stripe of the outer medulla. After three months, mice developed numerous cysts in proximal and distal tubules. The cysts had variable sizes and were lined with a single- or multilayered, flattened, cuboid or columnar epithelium. This resulted in epithelial hyperplasia, which was observed as protrusions into the cystic lumen in some of the renal cysts. The pre-cystic and cystic epithelium showed increased expression of cytoskeletal filaments and markers of epithelial injury and dedifferentiation. Additionally, the epithelium showed increased proliferation with an aberrant orientation of the mitotic spindle. These phenotypic tubular alterations led to progressive interstitial inflammation and fibrosis. Conclusions: In summary, Notch3 signaling promoted tubular cell proliferation, the alignment of cell division, dedifferentiation and hyperplasia, leading to cystic kidney diseases and pre-neoplastic lesions.     

Extracellular Vesicle Measurements with Nanoparticle Tracking Analysis: A Different Appreciation of Up and Down Secretion

As is the case with most eucaryotic cells, cancer cells are able to secrete extracellular vesicles (EVs) as a communication means towards their environment and surrounding cells. EVs are represented by microvesicles and smaller vesicles called exosomes, which are known for their involvement in cancer aggressiveness. The release of such EVs requires the intervention of trafficking-associated proteins, mostly represented by the RAB-GTPases family. In particular, RAB27A is known for its role in addressing EVs-to-be secreted towards the the plasma membrane. In this study, shRNAs targeting RAB27A were used in colorectal (CRC) and glioblastoma (GB) cell lines in order to alter EVs secretion. To study and monitor EVs secretion in cell lines’ supernatants, nanoparticle tracking analysis (NTA) was used through the NanoSight NS300 device. Since it appeared that NanoSight failed to detect the decrease in the EVs secretion, we performed another approach to drop EVs secretion (RAB27A-siRNA, indomethacin, Nexihnib20). Similar results were obtained i.e., no variation in EVs concentration. Conversely, NTA allowed us to monitor EVs up-secretion following rotenone treatment or hypoxia conditions. Therefore, our data seemed to point out the insufficiency of using only this technique for the assessment of EVs secretion decrease.     

Preventing and Reducing Bushfire Arson in Australia: A Review of What is Known

Bushfires are the leading cause of death and injuries from natural disasters in Australia, are responsible for hundreds of millions dollars in economic losses every year and seriously affect the country’s ecosystems. National data shows that half of these fires are deliberately lit with a significant proportion of these ignitions due to arson. This indicates the importance of arson research in any attempt to reduce unplanned fires. Strategies to prevent bushfire arson are examined from a criminological perspective. Much of the research on bushfire arson to date has focussed on identifying the motivations of arsonists and the paper shows the lack of utility of this approach. The difficulty of screening arsonists from employment with fire agencies is also discussed. More productive strategies include identifying and working with communities with high arson potential and early interventions with known arsonists or those at high risk of becoming one. The deterrence value of higher penalties is examined. The paper concludes that better data on bushfire ignitions and working with high risk communities and individuals offer the best chance of minimising bushfire ignitions in Australia at the present time.     

Serious Games

This special issue showcases developments in serious games that can have an impact on future research, development, and application of computer graphics and related techniques. The articles demonstrate the games' rich potential, spanning from health and culture applications to novel interaction techniques and support for 3D player data visualization.