Read by QxMD icon Read

Dynamic systems theory

Wataru Koshibae, Naoto Nagaosa
An emergent topological particle in magnets, skyrmion, has several unique features distinct from the other magnetic textures such as domain wall, helical structure, and vortex. It is characterized by a topological integer called skyrmion number N sk , which counts how many times the directions of the magnetic moments wrap the unit sphere. This N sk gives the chiral nature of the skyrmion dynamics, and leads to the extremely small critical current density j c for the current-driven motion in terms of spin transfer torque effect...
April 20, 2018: Scientific Reports
Itziar Irurzun-Arana, Alvaro Janda, Sergio Ardanza-Trevijano, Iñaki F Trocóniz
Numerous problems encountered in computational biology can be formulated as optimization problems. In this context, optimization of drug release characteristics or dosing schedules for anticancer agents has become a prominent area not only for the development of new drugs, but also for established drugs. However, in complex systems, optimization of drug exposure is not a trivial task and cannot be efficiently addressed through trial-error simulation exercises. Finding a solution to those problems is a challenging task which requires more advanced strategies like optimal control theory...
April 19, 2018: PLoS Computational Biology
Andrew Wildman, Ernesto Martinez-Baez, John L Fulton, Gregory K Schenter, Carolyn I Pearce, Aurora Evelyn Clark, Xiaosong Li
Ion pairing within complex solutions and elec- trolytes is a difficult phenomenon to mea- sure and investigate, yet it has signicant im- pact upon macroscopic processes, such as crys- tal formation. Traditional methods of detect- ing and characterizing ion pairing are sensi- tive to contact ion pairs, may require min- imum concentrations that limit applicability, and can have difficulty in characterizing solu- tions with many components. Because of its element specicity and sensitivity to local en- vironment, X-ray absorption near edge struc- ture (XANES) is a promising tool for investi- gating ion pairing in complex solutions...
April 19, 2018: Journal of Physical Chemistry Letters
Asam Latif, Justin Waring, Deborah Watmough, Matthew J Boyd, Rachel A Elliott
Reconfiguration of the healthcare division of labour is becoming increasingly attractive in the context of increased patient demand and resource constraints. One example is the introduction of extended roles for pharmacists to provide patients additional support to manage their medicines, while also reducing work pressures experienced by other health professionals. Understanding how such policies are framed by those delivering and receiving care has been under-theorised. Using Goffman's frame theory, we examine one newly introduced community pharmacy service (New Medicines Service (NMS)) to illustrate how a policy intended to support patient medicine-taking through the extended roles of pharmacists is framed and where this deviates from its proposed aims...
April 19, 2018: Sociology of Health & Illness
Lluis L Trulla, Nicola Di Stefano, Alessandro Giuliani
In sixth century BC, Pythagoras discovered the mathematical foundation of musical consonance and dissonance. When auditory frequencies in small-integer ratios are combined, the result is a harmonious perception. In contrast, most frequency combinations result in audible, off-centered by-products labeled "beating" or "roughness;" these are reported by most listeners to sound dissonant. In this paper, we consider second-order beats, a kind of beating recognized as a product of neural processing, and demonstrate that the data-driven approach of Recurrence Quantification Analysis (RQA) allows for the reconstruction of the order in which interval ratios are ranked in music theory and harmony...
2018: Frontiers in Psychology
Steven Jan
While the "units, events and dynamics" of memetic evolution have been abstractly theorized (Lynch, 1998), they have not been applied systematically to real corpora in music. Some researchers, convinced of the validity of cultural evolution in more than the metaphorical sense adopted by much musicology, but perhaps skeptical of some or all of the claims of memetics, have attempted statistically based corpus-analysis techniques of music drawn from molecular biology, and these have offered strong evidence in favor of system-level change over time (Savage, 2017)...
2018: Frontiers in Psychology
Ali Momeni, Kasra Rouhi, Hamid Rajabalipanah, Ali Abdolali
Inspired by the information theory, a new concept of re-programmable encrypted graphene-based coding metasurfaces was investigated at terahertz frequencies. A channel-coding function was proposed to convolutionally record an arbitrary information message onto unrecognizable but recoverable parity beams generated by a phase-encrypted coding metasurface. A single graphene-based reflective cell with dual-mode biasing voltages was designed to act as "0" and "1" meta-atoms, providing broadband opposite reflection phases...
April 18, 2018: Scientific Reports
Karla Batista-García-Ramó, Caridad Ivette Fernández-Verdecia
How the human brain works is still a question, as is its implication with brain architecture: the non-trivial structure–function relationship. The main hypothesis is that the anatomic architecture conditions, but does not determine, the neural network dynamic. The functional connectivity cannot be explained only considering the anatomical substrate. This involves complex and controversial aspects of the neuroscience field and that the methods and methodologies to obtain structural and functional connectivity are not always rigorously applied...
April 18, 2018: Behavioral Sciences
Adam E A Fouda, Gregory I Purnell, Nicholas A Besley
Resonant inelastic soft x-ray scattering maps for the water molecule are simulated by combining quantum chemical calculations of x-ray spectroscopy with ab initio molecular dynamics. The resonant inelastic scattering intensity is computed using the Kramers-Heisenberg formalism which accounts for channel interference and polarisation anisotropy. Algebraic diagrammatic construction and density functional theory based approaches for the calculation of the x-ray transition energies and transition dipole moments of the absorption and emission processes are explored...
April 18, 2018: Journal of Chemical Theory and Computation
Ariana Torres-Knoop, Ivan Kryven, Verena Schamboeck, Piet D Iedema
In the printing, coating and ink industries, photocurable systems are becoming increasingly popular and multi-functional acrylates are one of the most commonly used monomers due to their high reactivity (fast curing). In this paper, we use molecular dynamics and graph theory tools to investigate the thermo-mechanical properties and topology of hexanediol diacrylate (HDDA) polymer networks. The gel point was determined as the point where a giant component was formed. For the conditions of our simulations, we found the gel point to be around 0...
April 18, 2018: Soft Matter
Alexander T J Barron, Jenny Huang, Rebecca L Spang, Simon DeDeo
The French Revolution brought principles of "liberty, equality, fraternity" to bear on the day-to-day challenges of governing what was then the largest country in Europe. Its experiments provided a model for future revolutions and democracies across the globe, but this first modern revolution had no model to follow. Using reconstructed transcripts of debates held in the Revolution's first parliament, we present a quantitative analysis of how this body managed innovation. We use information theory to track the creation, transmission, and destruction of word-use patterns across over 40,000 speeches and a thousand speakers...
April 17, 2018: Proceedings of the National Academy of Sciences of the United States of America
Matthew D Egbert, Juan Pérez-Mercader
Life and other dissipative structures involve nonlinear dynamics that are not amenable to conventional analysis. Advances are being made in theory, modeling, and simulation techniques, but we do not have general principles for designing, controlling, stabilizing, or eliminating these systems. There is thus a need for tools that can transform high-level descriptions of these systems into useful guidance for their modification and design. In this article we introduce new methods for quantifying the viability of dissipative structures...
April 17, 2018: Artificial Life
S Bonetti, A D Bragg, A Porporato
The drainage area is an important, non-local property of a landscape, which controls surface and subsurface hydrological fluxes. Its role in numerous ecohydrological and geomorphological applications has given rise to several numerical methods for its computation. However, its theoretical analysis has lagged behind. Only recently, an analytical definition for the specific catchment area was proposed (Gallant & Hutchinson. 2011 Water Resour. Res. 47 , W05535. (doi:10.1029/2009WR008540)), with the derivation of a differential equation whose validity is limited to regular points of the watershed...
March 2018: Proceedings. Mathematical, Physical, and Engineering Sciences
Amartya S Banerjee, Lin Lin, Phanish Suryanarayana, Chao Yang, John E Pask
We describe a novel iterative strategy for Kohn-Sham density functional theory calculations aimed at large systems (> 1000 electrons), applicable to metals and insulators alike. In lieu of explicit diagonalization of the Kohn-Sham Hamiltonian on every self-consistent field (SCF) iteration, we employ a two-level Chebyshev polynomial filter based complementary subspace strategy to: 1) compute a set of vectors that span the occupied subspace of the Hamiltonian; 2) reduce subspace diagonalization to just partially occupied states; and 3) obtain those states in an efficient, scalable manner via an inner Chebyshev-filter iteration...
April 16, 2018: Journal of Chemical Theory and Computation
Martin Peter Bircher, Ursula Rothlisberger
Linear-response time-dependent density functional theory (LR-TDDFT) has become a valuable tool in the calculation of excited states of molecules of various sizes. However, standard generalised gradient approximation (GGA) and hybrid exchange-correlation (xc) functionals often fail to correctly predict charge-transfer (CT) excitations with low orbital overlap, thus limiting the scope of the method. The Coulomb-attenuation method (CAM) in the form of the CAM-B3LYP functional has been shown to reliably remedy this problem in many CT systems, making accurate predictions possible...
April 16, 2018: Journal of Chemical Theory and Computation
Adele Diederich, Jennifer S Trueblood
Many phenomena in judgment and decision making are often attributed to the interaction of 2 systems of reasoning. Although these so-called dual process theories can explain many types of behavior, they are rarely formalized as mathematical or computational models. Rather, dual process models are typically verbal theories, which are difficult to conclusively evaluate or test. In the cases in which formal (i.e., mathematical) dual process models have been proposed, they have not been quantitatively fit to experimental data and are often silent when it comes to the timing of the 2 systems...
March 2018: Psychological Review
Oscar A Douglas-Gallardo, Cristián Gabriel Sánchez, Esteban Vöhringer-Martinez
Nowadays, the search for efficient methods able to reduce the high atmospheric carbon dioxide concentration has turned into a very dynamic research area. Several environmental problems have been closely associated with the high atmospheric level of this greenhouse gas. Here, a novel system based on the use of surface-functionalized silicon quantum dots (sf-SiQDs) is theoretically proposed as a versatile device to bind carbon dioxide. Within this approach, carbon dioxide trapping is modulated by a photoinduced charge redistribution between the capping molecule and the silicon quantum dots (SiQDs)...
April 14, 2018: Journal of Chemical Physics
Arvi Rauk
β-N-Methylamino-L-alanine (BMAA) is a neurotoxic agent implicated in ALS, Parkinson's and Alzheimer's diseases. It is produced by blue-green algae and could find its way via fish and seafood into the human food supply. Isolation from biological samples yields the compound in monomeric and protein-bound form. It has been suggested that the protein-bound fraction may result from genetic misincorporation into proteins in place of serine. Concomitant misfolding of the mutated proteins may be responsible for the neurological diseases...
April 12, 2018: Journal of Physical Chemistry. B
Gregory A Ross, Ariën S Rustenburg, Patrick B Grinaway, Josh Fass, John Damon Chodera
Biomolecular simulations are typically performed in an aqueous environment where the number of ions remains fixed for the duration of the simulation, generally with either a minimally neutralizing ion environment or a number of salt pairs intended to match the macroscopic salt concentration. In contrast, real biomolecules experience local ion environments where the salt concentration is dynamic and may differ from bulk. The degree of salt concentration variability and average deviation from the macroscopic concentration remains, as yet, unknown...
April 13, 2018: Journal of Physical Chemistry. B
Andrew J Wilson, Prashant K Jain
Oxygenic photosynthesis in nature occurs via water splitting catalyzed by the oxygen evolving complex (OEC) of photo-system II. To split water, the OEC cycles through a sequence of oxidation states (Si , i = 0-4), the structural mechanism of which is not fully understood under physiological conditions. We monitored the OEC in visible light-driven water-splitting action by using in-situ, aqueous-environment surface-enhanced Raman scattering (SERS). In the unexplored low-frequency region of SERS, we found dynamic vibrational signatures of water binding and splitting...
April 12, 2018: Journal of the American Chemical Society
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"