Negative tension controls stability and structure of intermediate filament networks

Networks, whose junctions are free to move along the edges, such as two-dimensional soap froths and membrane tubular networks of endoplasmic reticulum are intrinsically unstable. This instability is a result of a positive tension applied to the network elements. A paradigm of networks exhibiting stable polygonal configurations in spite of the junction mobility, are networks formed by bundles of Keratin Intermediate Filaments (KIFs) in live cells. A unique feature of KIF networks is a, hypothetically, negative tension generated in the network bundles due to an exchange of material between the network and an effective reservoir of unbundled filaments. Here we analyze the structure and stability of two-dimensional networks with mobile three-way junctions subject to negative tension. First, we analytically examine a simplified case of hexagonal networks with symmetric junctions and demonstrate that, indeed, a negative tension is mandatory for the network stability. Another factor contributing to the network stability is the junction elastic resistance to deviations from the symmetric state. We derive an equation for the optimal density of such networks resulting from an interplay between the tension and the junction energy. We describe a configurational degeneration of the optimal energy state of the network. Further, we analyze by numerical simulations the energy of randomly generated networks with, generally, asymmetric junctions, and demonstrate that the global minimum of the network energy corresponds to the irregular configurations.

Hybrid inflation and waterfall field in string theory from D7-branes

We present an explicit string realisation of a cosmological inflationary scenario we proposed recently within the framework of type IIB flux compactifications in the presence of three magnetised D7-brane stacks. Inflation takes place around a metastable de Sitter vacuum. The inflaton is identified with the volume modulus and has a potential with a very shallow minimum near the maximum. Inflation ends due to the presence of “waterfall” fields that drive the evolution of the Universe from a nearby saddle point towards a global minimum with tuneable vacuum energy describing the present state of our Universe.

Penerapan Bat Algorithm Dalam Penyelsaian Kasus Travelling Salesman Problem (TSP) Pada Internship Program

This optimization is an optimization case that organizes all possible and feasible solutions in discrete form. One form of combinatorial optimization that can be used as material in testing a method is the Traveling Salesman Problem (TSP). In this study, the bat algorithm will be used to find the optimum value in TSP. Utilization of the Metaheuristic Algorithm through the concept of the Bat Algorithm is able to provide optimal results in searching for the shortest distance in the case of TSP. Based on trials conducted using data on the location of student street vendors, the Bat Algortima is able to obtain the global minimum or the shortest distance when compared to the nearest neighbor method, Hungarian method, branch and bound method.

Hydrogen Delocalization in an Asymmetric Biomolecule: The Curious Case of Alpha-Fenchol

Rotational microwave jet spectroscopy studies of the monoterpenol α-fenchol have so far failed to identify its second most stable torsional conformer, despite computational predictions that it is only very slightly higher in energy than the global minimum. Vibrational FTIR and Raman jet spectroscopy investigations reveal unusually complex OH and OD stretching spectra compared to other alcohols. Via modeling of the torsional states, observed spectral splittings are explained by delocalization of the hydroxy hydrogen atom through quantum tunneling between the two non-equivalent but accidentally near-degenerate conformers separated by a low and narrow barrier. The energy differences between the torsional states are determined to be only 16(1) and 7(1) cm−1hc for the protiated and deuterated alcohol, respectively, which further shrink to 9(1) and 3(1) cm−1hc upon OH or OD stretch excitation. Comparisons are made with the more strongly asymmetric monoterpenols borneol and isopinocampheol as well as with the symmetric, rapidly tunneling propargyl alcohol. In addition, the third—in contrast localized—torsional conformer and the most stable dimer are assigned for α-fenchol, as well as the two most stable dimers for propargyl alcohol.

ANALISIS PERKUATAN DAN PENANGANAN TIMBUNAN BADAN JALAN TOL TRANS SUMATERA SEKSI V PEKANBARU-DUMAI DENGAN STRUKTUR PILE EMBANKMENT

Jalan Tol Trans Sumatera Pekanbaru-Dumai merupakan ruas jalan tol utama karena digunakan untuk mobilisasi dan bisnis kota Pekanbaru-Dumai. Timbunan pada badan Jalan Tol Trans Sumatera merupakan faktor penting untuk struktur geoteknik di sekitar lereng yang berada di badan jalan tol. Timbunan tanah pada badan jalan tol digunakan untuk pencapaian elevasi akhir subgrade tanah. Pengaruh analisis stabilitas lereng serta penurunan konsolidasi tanah sangat berpengaruh pada analisis struktur geoteknik untuk timbunan tanah. Permasalahan yang terjadi adalah terjadi penurunan yang disertai kelongsoran sebagian lebar badan jalan di STA 79+ 615. Jalan Tol Trans Sumatera Seksi V Pekanbaru-Dumai dan box culvert tanah dasar mengalami penurunan. Kerusakan yang terjadi pada kedua lokasi berupa penurunan disertai retakan arah jalan dengan pergeseran tanah kearah samping (longsor). Analisis terhadap sisi geoteknik menggunakan perkuatan salah satunya menggunakan struktur pile embankment. Pada analisis perkuatan dan penanganan timbunan menggunakan struktur pile embankment akan dilakukan analisis faktor keamanan timbunan jalan. Parameter perkuatan dan penanganan timbunan tanah (sudut geser dalam, poisson ratio, kohesi, modulus elastisitas, dan muka air tanah) dapat digunakan untuk analisis struktur geoteknik berikutnya. Analisis perkuatan akan menggunakan aplikasi Plaxis (program analisis geoteknik dengan basis finite element method). Direncanakan untuk pile embankment dengan tipe spun pile dapat mencapai nilai safety factor 1,5 (faktor keamanan terhadap stabilitas global minimum SNI 8460-2017) dan mencapai nilai safety factor 1,1 (faktor keamanan terhadap beban gempa SNI 8460-2017) dengan dimensi spun pile diameter 60 cm, panjang efektif 10-12 meter dengan jarak spasi antar spun pile adalah 3 meter, dan tebal LTP (Load Transfer Platform) sebesar 1,8 meter.

Vibrational Spectroscopy of Homo- and Heterochiral Amino Acid Dimers: Conformational Landscapes

The homo- and heterochiral protonated dimers of asparagine with serine and with valine were investigated using infrared multiple-photon dissociation (IRMPD) spectroscopy. Extensive quantum-chemical calculations were used in a three-tiered strategy to screen the conformational spaces of all four dimer species. The resulting binary structures were further grouped into five different types based on their intermolecular binding topologies and subunit configurations. For each dimer species, there are eight to fourteen final conformational geometries within a 10 kJ mol−1 window of the global minimum structure for each species. The comparison between the experimental IRMPD spectra and the simulated harmonic IR features allowed us to clearly identify the types of structures responsible for the observation. The monomeric subunits of the observed homo- and heterochiral dimers are compared to the corresponding protonated/neutral amino acid monomers observed experimentally in previous IRMDP/rotational spectroscopic studies. Possible chirality and kinetic influences on the experimental IRMPD spectra are discussed.

Towards a Right to Learn: Concepts and Measurement of Global Education Poverty

The idea that children have a “right to education” has been widely accepted since the Universal Declaration of Human Rights in 1948 (United Nations, 1948) and periodically reinforced since. The “right to education” has always, explicitly or implicitly, encompassed a “right to learn.” Measures of schooling alone, such as enrollment or grade attainment, without reference to skills, capabilities, and competencies acquired, are inadequate for defining education or education poverty. Because of education’s cumulative and dynamic nature, education poverty needs an “early” standard (e.g., Grade 3 or 4 or age 8 or 10) and a “late” standard (e.g., Grade 10 or 12 or ages 15 and older). Further, as with all international poverty definitions, there needs to be a low, extreme standard, which is found almost exclusively in low- and middle-income countries and can inform prioritization and action, and a higher “global” standard, against which even some children in high income countries would be considered education poor but which is considered a reasonable aspiration for all children. As assessed against any proposed standard, we show there is a massive learning crisis: students spend many years in school and yet do not reach an early standard of mastery of foundational skills nor do they reach any reasonable global minimum standard by the time they emerge from school. The overwhelming obstacle to addressing education poverty today is not enrollment/grade attainment nor inequality in learning achievement, but the fact that the typical learning profile is just too shallow for children to reach minimum standards.

Utilising angle-dependent critical current data in the electromagnetic modelling of HTS coils

A detailed methodology is presented for modelling the electromagnetic characteristics of HTS coils using angle-dependent critical current data obtained from experimental measurements of real wire samples. The results of such an analysis are contrasted with those obtained using more prevalent approaches such as a global minimum critical current method or an elliptical field magnitude-dependent functional approximation. Several interesting design consequences of significance to real-world devices that emerge only when the full anisotropy of real wires is taken into account are outlined and discussed. These include the beneficial impact on various performance metrics of the adoption of mixed conductor windings, the importance of coil orientation in optimising device performance, and the potential opportunity to derive a specific design benefit from the targeted use of conductors possessing inclined planarity.

A Global Optimization Algorithm for Unconstrained Non-linear Optimization Problems Using Chaotic Neuron Map and Golden Number

This paper presents aninnovative global multi-variable optimization algorithm using one of the best chaotic sequences, the neuron map, a description of which is also provided in the paper. The algorithm uses neuron map in the first stage to move near the global minimum point, as well as in each iteration of the second stage of local search that is done using the N-dimensional golden section search algorithm. The generation and mapping of the neuron variables to the optimization variables along with the stagewise search for the global minimum is explained conscientiously in the work. Numerical results on some benchmark functions and the comparison with a latest state-of-the-art algorithm ispresented in order to demonstrate the efficiency of the proposed algorithm.

Constrained global optimization of multivariate polynomials using polynomial B-spline form and B-spline consistency prune approach

In this paper, we propose basic and improved algorithms based on polynomial B-spline form for constrained global optimization of multivariate polynomial functions. The proposed algorithms are based on a branch-and-bound framework. In improved algorithm we introduce several new ingredients, such as B-spline box consistency and B-spline hull consistency algorithm to prune the search regions and make the search more efficient. The performance of the basic and improved algorithm is tested and compared on set of test problems. The results of the tests show the superiority of the improved algorithm over the basic algorithm in terms of the chosen performance metrics. We compare optimal value of global minimum obtained using the proposed algorithms with CENSO, GloptiPoly and several state-of-the-art NLP solvers, on set of $11$ test problems. The results of the tests show the superiority of the proposed algorithm and CENSO solver (open source solver for global optimization of B-spline constrained problem) in that it always captures the global minimum to the user-specified accuracy.