Coherence in Large-Scale Networks: Dimension-Dependent Limitations of Local Feedback

We consider distributed consensus and vehicular formation control problems. Specifically we address the question of whether local feedback is sufficient to maintain coherence in large-scale networks subject to stochastic disturbances. We define macroscopic performance measures which are global quantities that capture the notion of coherence; a notion of global order that quantifies how closely the formation resembles a solid object. We consider how these measures scale asymptotically with network size in the topologies of regular lattices in 1, 2 and higher dimensions, with vehicular platoons corresponding to the 1 dimensional case. A common phenomenon appears where a higher spatial dimension implies a more favorable scaling of coherence measures, with a dimensions of 3 being necessary to achieve coherence in consensus and vehicular formations under certain conditions. In particular, we show that it is impossible to have large coherent one dimensional vehicular platoons with only local feedback. We analyze these effects in terms of the underlying energetic modes of motion, showing that they take the form of large temporal and spatial scales resulting in an accordion-like motion of formations. A conclusion can be drawn that in low spatial dimensions, local feedback is unable to regulate large-scale disturbances, but it can in higher spatial dimensions. This phenomenon is distinct from, and unrelated to string instability issues which are commonly encountered in control problems for automated highways.Comment: To appear in IEEE Trans. Automat. Control; 15 pages, 2 figure

Grounded Theory of Consumer Loyalty: A Perspective through Video Game Addiction

Game addiction has become an extremely important topic in psychology researchers, particularly in understanding and explaining why individuals become addicted (to video games). In previous studies, effect of online game addiction on social responsibilities, health problems, government action, and the behaviors of individuals to purchase and the causes of making individuals addicted on the video games has been discussed. Extending these concepts in marketing, it could be argued than the phenomenon could enlighten and extending our understanding on consumer loyalty. This study took the Grounded Theory approach, and found that motivation, satisfaction, fulfillments, exploration and achievements to be part of the important elements that builds consumer loyalty

Isolation and characterization of microsatellite loci from two inbreeding bark beetle species (Coccotrypes)

We developed 14 microsatellite markers in Coccotrypes carpophagus and 14 in C. dactyliperda. These loci will be used for studying genetic structure and the level of inbreeding in populations in the Canary Islands and Madeira. As a result of long-term inbreeding, genetic variability is relatively low in these bark beetle species. We found one to five alleles per locus in 29 C. carpophagus and 41 C. dactyliperda from various localities. Eleven of the markers developed for C. carpophagus amplified in C. dactyliperda and seven of the markers developed for C. dactyliperda amplified in C. carpophagus

Computer-aided approaches reveal trihydroxychroman and pyrazolone derivatives as potential inhibitors of SARS-CoV-2 virus main protease

COVID-19 was declared a pandemic by the World Health Organization (WHO) in March 2020. The disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The aim of this study is to target the SARS-CoV-2 virus main protease (Mpro) via structure-based virtual screening. Consequently, > 580,000 ligands were processed via several filtration and docking steps, then the top 21 compounds were analysed extensively via MM-GBSA scoring and molecular dynamic simulations. Interestingly, the top compounds showed favorable binding energies and binding patterns to the protease enzyme, forming interactions with several key residues. Trihydroxychroman and pyrazolone derivatives, SN02 and SN18 ligands, exhibited very promising binding modes along with the best MM-GBSA scoring of –40.9 and –41.2 kcal mol–1, resp. Hence, MD simulations for the ligand-protein complexes of SN02 and SN18 affirmed the previously attained results of the potential inhibition activity of these two ligands. These potential inhibitors can be the starting point for further studies to pave way for the discovery of new antiviral drugs for SARS-CoV-2

The Effects of Adhering to ACSM Physical Activity Guidelines on Female University Employees

Despite the well-established benefits of regular physical activity (PA), 50.9% of Americans do not meet the American College of Sports Medicine (ACSM) guidelines for cardiorespiratory, resistance, and flexibility exercise. Physical inactivity, low cardiovascular fitness (CVF), obesity and body fat percentage (BF%) are risk factors for increased cardiometabolic morbidity and mortality. Universities, despite the increased educational awareness, create sedentary environments that do not promote PA, thus jeopardizing their employees’ health. PURPOSE: To educate university employees about the health-related benefits of PA and the time frame is needed to start seeing changes by meeting the minimum of the ACSM PA guidelines. METHODS: Female physical inactive university employees were targeted (Age 40 ± 11 yrs, Body weight 76.9 ± 4.4 kg). Participants underwent basic anthropometric (body weight, waist circumference, waist hip ratio), mean arterial pressure, body composition (using bioelectric impedance analysis) measurements, and a submaximum oxygen consumption test (using a Bruce protocol) as baseline measurements. Participants were given the ACSM guidelines and instructed to follow these for 12 weeks. No other control was made on participants’ lifestyle factors between the pre- and post-measurements, other than the day before to replicate their diet, PA and sleep patterns. They were given a Fitbit(c) tracker to record and monitor their PA activity levels so they meet the weekly PA guidelines. This is an ongoing funded project from the Advancement of Interprofessional Collaboration and Education (ADVICE) project, and the reported results reflect pre- and post-values from end of week 1 to end of week 4 (N=4). Thus, all measurements were repeated after 4 weeks of the intervention. One-way factorial ANOVA by time was used to detect changes between Week 1 and Week 4. Significance was set at p \u3c 0.05. All analyses were performed using SPSS(c). RESULTS: BF% was significantly reduced by 38.8% (F1,5 = 9.943, p = .025, η2 = .665). All the remaining examined variables were improved by week-4 presenting practical but were not statistically significant (p \u3e .005). Lean mass was increased by 15.6%, mean arterial pressure was reduced by 9.6%, waist circumference was reduced by 5.7%, waist hip ratio was reduced by 20.7%, minutes of being physically active were increased by 13.7%, and predicted maximum oxygen consumption was increased by 4%. CONCLUSION: Following the ACSM PA guidelines for just 4 weeks and increasing the minutes of being physically by 13.7% it was enough to improve BF% and other associated cardiometabolic disease risk factors. Even though these results represent preliminary data from small sample size the practical significance of this study is that university employees can improve their risks factors for cardiometabolic morbidity and mortality by adhering to the ACSM PA guidelines for even 4 weeks

Multi-scale modelling of strongly heterogeneous 3D composite structures using spatial Voronoi tessellation

Abstract3D composite materials are characterized by complex internal yarn architectures, leading to complex deformation and failure development mechanisms. Net-shaped preforms, which are originally periodic in nature, lose their periodicity when the fabric is draped, deformed on a tool, and consolidated to create geometrically complex composite components. As a result, the internal yarn architecture, which dominates the mechanical behaviour, becomes dependent on the structural geometry. Hence, predicting the mechanical behaviour of 3D composites requires an accurate representation of the yarn architecture within structural scale models. When applied to 3D composites, conventional finite element modelling techniques are limited to either homogenised properties at the structural scale, or the unit cell scale for a more detailed material property definition. Consequently, these models fail to capture the complex phenomena occurring across multiple length scales and their effects on a 3D composite’s mechanical response. Here a multi-scale modelling approach based on a 3D spatial Voronoi tessellation is proposed. The model creates an intermediate length scale suitable for homogenisation to deal with the non-periodic nature of the final material. Information is passed between the different length scales to allow for the effect of the structural geometry to be taken into account on the smaller scales. The stiffness and surface strain predictions from the proposed model have been found to be in good agreement with experimental results.The proposed modelling framework has been used to gain important insight into the behaviour of this category of materials. It has been observed that the strain and stress distributions are strongly dependent on the internal yarn architecture and consequently on the final component geometry. Even for simple coupon tests, the internal architecture and geometric effects dominate the mechanical response. Consequently, the behaviour of 3D woven composites should be considered to be a structure specific response rather than generic homogenised material properties

Identification of the Cellular Mechanisms That Modulate Trafficking of Frizzled Family Receptor 4 (FZD4) Missense Mutants Associated With Familial Exudative Vitreoretinopathy

Citation: Milhem RM, Ben-Salem S, AlGazali L, Ali BR. Identification of the cellular mechanisms that modulate trafficking of frizzled family receptor 4 (FZD4) missense mutants associated with familial exudative vitreoretinopathy. Invest Ophthalmol Vis Sci. 2014;55:3423-3431. DOI:10.1167/ iovs.14-13885 PURPOSE. Fifteen missense mutations in the frizzled family receptor 4 (FZD4) reported to cause familial exudative vitreoretinopathy (FEVR) were evaluated to establish the pathological cellular mechanism of disease and to explore novel therapeutic strategies. METHODS. The mutations were generated by site-directed mutagenesis and expressed in HeLa and COS-7 cell lines. Confocal fluorescence microscopy and N-glycosylation profiling were used to observe the subcellular localization of the mutant proteins relative to wild-type (WT). Polyubiquitination studies were used to establish the involvement of the proteasome. Culturing at reduced temperatures and incubation in the presence of chemical compounds were used to enhance mutant protein processing and exit out of the endoplasmic reticulum (ER). RESULTS. Confocal fluorescence microscopy of the mutants showed three distinct subcellular localizations, namely, a plasma membrane pattern, an ER pattern, and a mixed pattern to both compartments. Confocal fluorescence microscopy and N-glycosylation profiling established the predominant ER localization of P33S, G36N, H69Y, M105T, M105V, C181R, C204R, C204Y, and G488D mutants. Coexpression of these mutants with WT FZD4 showed the inability of the mutants to trap WT FZD4. Culturing the expressing cells at reduced temperatures or in the presence of chemical agents directed at ameliorating protein misfolding resulted in partial rescue of trafficking defects observed for M105T and C204Y mutants. CONCLUSIONS. Defective trafficking resulting in haploinsufficiency is a major cellular mechanism for several missense FEVR-causing FZD4 mutants. Our findings indicate that this trafficking defect might be correctable for some mutants, which may offer opportunities for the development of novel therapeutics approaches for this condition

Impact of dielectric separation on transition point and accessible flow enthalpy of inductive plasmas

In order to develop inductive electric propulsion systems towards flight-ready status, an investigation into the influence of the dielectric separation between plasma and inductive coil has been conducted. This was completed by varying the wall thickness of the thruster discharge tube. The investigation assessed discharges of argon and an argon-nitrogen mixture. Additionally, results of a similar investigation utilising air have been included for comparison. The sum of these investigations showed two contrasting trends. The argon condition exhibited a preference for thicker walls, with transitions to the higher inductive regime occurring at lower input powers with increasing wall thickness. Results for Ar:N2 and air showed the opposite, with system thermal power increasing with decreasing wall thicknesses. This behaviour has been proposed to include contributions of both the mechanical dielectric separation caused by the choice of chamber wall thickness, and the gasdynamic dielectric separation owing to the discharge thermal boundary laye